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Bioactive glass nanoparticles (BGNs) are well-recognized multifunctional biomaterials for bone tissue regeneration due to their capability to stimulate various cellular processes through released biologically active ions. Understanding the correlation between BGN composition and cellular responses is key to developing clinically usable BGN-based medical devices. This study investigated the influence of CaO content of binary SiO 2 -CaO BGNs (CaO ranging from 0 to 10 mol%) on osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) and in vivo bone regeneration in zebrafish osteoporosis model. The results showed that BGNs could promote osteogenic differentiation of rBMSCs by indirectly releasing active ions or directly interacting with rBMSCs by internalization. In both situations, BGNs of a higher CaO content could promote the osteogenic differentiation of rBMSCs to a greater extent. The internalized BGNs could activate the transcription factors RUNX2 and OSX, leading to the expression of osteogenesis-related genes. The results in the zebrafish osteoporosis model indicated that the presence of BGNs of higher CaO contents could enhance bone regeneration and rescue dexamethasone-induced osteoporosis to a greater extent. These findings demonstrate that BGNs can stimulate osteogenic differentiation of rBMSCs by releasing active ions or internalization. A higher CaO content facilitates osteogenesis and bone regeneration of zebrafish as well as relieving dexamethasone-induced osteoporosis. The zebrafish osteoporosis model can be a potent tool for evaluating the in vivo bone regeneration effects of bioactive materials. Bioactive glass nanoparticles (BGNs) are increasingly used as fillers of nanocomposites or as delivery platforms of active ions to regenerate bone tissue. Various studies have shown that BGNs can enhance osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) by releasing active ions. However, the correlation between BGN composition and cellular responses and in vivo bone regeneration effect has still not been well investigated. Establishment of a suitable in vivo animal model for investigating this correlation is also challenging. The present study reports the influence of CaO content in binary SiO 2 -CaO BGNs on osteogenic differentiation of BMSCs extracellularly and intracellularly. This study also demonstrates the suitability of zebrafish osteoporosis model to investigate in vivo bone regeneration effect of BGNs. [Display omitted] [ABSTRACT FROM AUTHOR]

As liposomes have been widely explored as drug delivery carriers over the past decades, they are one of the most promising platforms due to their biocompatibility and versatility for surface functionalization. However, to improve the specific design of liposomes for future biomedical applications such as nanovaccines, it is necessary to understand how these systems interact with cell membranes, as most of their potential applications require them to be internalized by cells. Even though several investigations on the cellular uptake of liposomes were conducted, the effect of the liposome membrane properties on internalization in different cell lines remains unclear. Here, we demonstrate how the cellular uptake behavior of liposomes can be driven towards preferential interaction with dendritic cells (DC2.4) as compared to macrophages (RAW264.7) by tuning the lipid composition with varied molar ratios of the lipid 1,2-dioleoyl- sn -glycero-3-phosphoethanolamine (DOPE). Cellular internalization efficiency was analyzed by flow cytometry, as well as liposome-cell membrane co-localization by confocal laser scanning microscopy. The corresponding proteomic analysis of the protein corona was performed in order to unravel the possible effect on the internalization. The obtained results of this work reveal that it is possible to modulate the cellular uptake towards enhanced internalization by dendritic cells just by modifying the applied lipids and, thus, mainly the physico-chemical properties of the liposomes. In the field of nanomedicine, it is of key importance to develop new specific and efficient drug carriers. In this sense, liposomes are one of the most widely known carrier types and used in clinics with good results. However, the exact interaction mechanisms of liposomes with cells remain unclear, which is of great importance for the design of new drug delivery platforms. Therefore, in this work we demonstrate that cellular uptake depends on the lipid composition. We are able to enhance the uptake in a specific cell type just by tuning the content of a lipid in the liposome membrane. This finding could be a step towards the selective design of liposomes to be internalized by specific cells with promising applications in biomedicine. [Display omitted] [ABSTRACT FROM AUTHOR]

Biopolymeric nanoparticles like chitosan, gelatin, alginate, and chitosan-alginate were prepared using different methods to deliver drugs to the brain. The hydrodynamic size of the synthesised nanoparticles ranged from 49 nm to 383 nm for the concentration of nanoparticles studied. The zeta potential measurements ranged from −1.71 mV to +26 mV for the synthesised nanoparticles. Structural characterisation by XRD and FT IR indicated encapsulation of lithium. The porous structure of chitosan nanoparticles with lithium was observed by HR SEM. The nanoformulations were evaluated for in vitro proliferation study using MTT assay using the PC 12 cell lines, and the cellular uptake of the nanoformulations was assessed using ICP-OES. Cellular uptake of lithium carbonate in chitosan nanoparticles showed the maximum cellular uptake by the PC 12 cells with 70.63% compared to other groups. Chitosan nanoparticles in the present study seem to be an ideal carrier of lithium. [ABSTRACT FROM AUTHOR]

The central nervous system (CNS) is protected by the blood-brain barrier (BBB), which acts as a physical barrier to regulate and prevent the uptake of endogenous metabolites and xenobiotics. However, the BBB prevents most non-lipophilic drugs from reaching the CNS following systematic administration. Therefore, there is considerable interest in identifying drug carriers that can maintain the biostability of therapeutic molecules and target their transport across the BBB. In this regard, upconversion nanoparticles (UCNPs) have become popular as a nanoparticle-based solution to this problem, with the additional benefit that they display unique properties for in vivo visualization. The majority of studies to date have explored basic spherical UCNPs for drug delivery applications. However, the biophysical properties of UCNPs, cell uptake and BBB transport have not been thoroughly investigated. In this study, we described a one-pot seed-mediated approach to precisely control longitudinal growth to produce bright UCNPs with various aspect ratios. We have systematically evaluated the effects of the physical aspect ratios and PEGylation of UCNPs on cellular uptake in different cell lines and an in vivo zebrafish model. We found that PEGylated the original UCNPs can enhance their biostability and cell uptake capacity. We identify an optimal aspect ratio for UCNP uptake into several different types of cultured cells, finding that this is generally in the ratio of 2 (length/width). This data provides a crucial clue for further optimizing UCNPs as a drug carrier to deliver therapeutic agents into the CNS. The central nervous system (CNS) is protected by the blood-brain barrier (BBB), which acts as a highly selective semipermeable barrier of endothelial cells to regulate and prevent the uptake of toxins and pathogens. However, the BBB prevents most non-lipophilic drugs from reaching the CNS following systematic administration. The proposed research is significant because identifying the aspect ratio of drug carriers that maintains the biostability of therapeutic molecules and targets their transport across the blood-brain barrier (BBB) is crucial for designing an efficient drug delivery system. Therefore, this research provides a vital clue for further optimizing UCNPs as drug carriers to deliver therapeutic molecules into the brain. [Display omitted] [ABSTRACT FROM AUTHOR]

DNA nanotechnology has yielded remarkable advances in composite materials with diverse applications in biomedicine. The specificity and predictability of building 3D structures at the nanometer scale make DNA nanotechnology a promising tool for uses in biosensing, drug delivery, cell modulation, and bioimaging. However, for successful translation of DNA nanostructures to real-world applications, it is crucial to understand how they interact with living cells, and the consequences of such interactions. In this review, we summarize the current state of knowledge on the interactions of DNA nanostructures with cells. We identify key challenges, from a cell biology perspective, that influence progress towards the clinical translation of DNA nanostructures. We close by providing an outlook on what questions must be addressed to accelerate the clinical translation of DNA nanostructures. Self-assembled DNA nanostructures (DNs) offers unique opportunities to overcome persistent challenges in the nanobiotechnology field. However, the interactions between engineered DNs and living cells are still not well defined. Critical systematization of current cellular models and biological responses triggered by DNs is a crucial foundation for the successful clinical translation of DNA nanostructures. Moreover, such an analysis will identify the pitfalls and challenges that are present in the field, and provide a basis for overcoming those challenges. [Display omitted] [ABSTRACT FROM AUTHOR]

The use of small interfering RNAs (siRNAs) has been under investigation for the treatment of several unmet medical needs, including acute lung injury/acute respiratory distress syndrome (ALI/ARDS) wherein siRNA may be implemented to modify the expression of pro-inflammatory cytokines and chemokines at the mRNA level. The properties such as clear anatomy, accessibility, and relatively low enzyme activity make the lung a good target for local siRNA therapy. However, the translation of siRNA is restricted by the inefficient delivery of siRNA therapeutics to the target cells due to the properties of naked siRNA. Thus, this review will focus on the various delivery systems that can be used and the different barriers that need to be surmounted for the development of stable inhalable siRNA formulations for human use before siRNA therapeutics for ALI/ARDS become available in the clinic. The pulmonary administration of siRNA in an appropriate delivery vector seems promising to treat undruggable lung diseases such as acute lung injury/acute respiratory distress syndrome ALI/ARDS. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] Cutaneous melanoma is one of the most common malignant skin cancer with high lethality. Chemotherapy and photothermal therapy are important and extensively studied treatment modalities for melanoma. However, these therapies still face some challenges, which severely restrict their further applications, such as unsatisfactory efficacy of monotherapy, nonspecific uptake and release during drug delivery, and unexpected adverse effects from system administration. Recently, the strategies of collaboration, functional modification, stimuli-responsive design, and topical administration all show great prospect for solving above problems. In this research, a multifunctional nanoparticle-integrated dissolving microneedle drug delivery system was constructed, in which the nanoparticles were prepared based on the framework with the incorporation of photothermal agent (CuS) into Zeolitic imidazolate framework-8 and functionalized by hyaluronic acid. This system can co-load multi-modal drugs, improve specific uptake and distribution of targeted tumor, deliver drug locally, and release drug intelligently and spatiotemporally, thereby promising a low-dose administration with high efficiency. The high inhibiting tumor performance and excellent systematic safety were verified both in vitro and in vivo. Together, this smart design overcame the drawbacks of monotherapy and conventional system administration. We believe the nanoparticle-integrated dissolving microneedles will be in prospect of clinical application for more superficial tumors with further delicate optimization. Melanoma is one of the most common skin cancers with high lethality. Extensively studied chemotherapy and photothermal therapy still face some challenges, such as the limited therapeutic efficacy and the severe system adverse effects. In order to overcome these drawbacks, the multifunctional nanoparticle-integrated dissolving microneedles (DMNs) were designed. Especially, the nanoparticles could co-load multi-modal drugs, improve specific uptake, and release drug intelligently and spatiotemporally. The microneedles could increase the drug accumulation in tumor, thus achieving excellent therapeutic efficacy and reducing side effects. This system paved the way to a less invasive, more focused and efficient therapeutic strategy for melanoma therapy. [ABSTRACT FROM AUTHOR]

As the driving force of tumor progression, cancer stem cells (CSCs) hold much lower cellular stiffness than bulk tumor cells across many cancer types. However, it remains unclear whether low cell stiffness can be harnessed in nanoparticle-based therapeutics for CSC targeting. We report that breast CSCs exhibit much lower stiffness but considerably higher uptake of nitrogen-doped graphene quantum dots (N-GQDs) than bulk tumor cells. Softening/stiffening cells enhances/suppresses nanoparticle uptake through activating/inhibiting clathrin- and caveolae-mediated endocytosis, suggesting that low cell stiffness mediates the elevated uptake in soft CSCs that may lead to the specific elimination. Further, soft CSCs enhance drug release, cellular retention, and nuclear accumulation of drug-loaded N-GQDs by reducing intracellular pH and exocytosis. Remarkably, drug-loaded N-GQDs specifically eliminate soft CSCs both in vitro and in vivo , inhibit tumor but not animal growth, and reduce the tumorigenicity of xenograft cells. Our findings unveil a new mechanism by which low cellular stiffness can be harnessed in nanoparticle-based strategies for specific CSC elimination, opening a new paradigm of cancer mechanomedicine. Low cell stiffness is associated with high malignancy of tumor cells and thus serves as a mechanical hallmark of CSCs. However, it remains unclear whether cellular stiffness can be exploited for specific targeting of soft CSCs. This work reports that soft CSCs exhibit high N-GQD uptake compared to stiff tumor cells, which is regulated by cellular stiffness. Further, soft CSCs have enhanced drug release, cellular retention, and nuclear accumulation of drug-loaded N-GQDs, which enable the specific elimination of malignant CSCs both in vitro and in vivo with minimal side effect. In summary, our study demonstrates that CSC's low stiffness can be harnessed as a mechanical target for specific eradication, which provides a new paradigm of cancer mechanomedicine. [Display omitted] [ABSTRACT FROM AUTHOR]

Radio-sensitization is highly desired to reduce side-effect of the harsh dose of radiation therapy (RT), for which nanoparticles with high atomic number elements provide a promising tool. However, insufficient knowledge on utilizing the interaction between nanoparticles and cancerous cells hampers the improvement of therapeutic outcome. We herein employed NaGdF 4 :Yb,Er nano-crystals as the sensitizer, and modified them with a tumor targeting agent and a mitochondria targeting moiety, separately and jointly, to achieve varied extent of mitochondrial accumulation. We observed that NaGdF 4 :Yb,Er nano-crystal, even unmodified with targeting ligands, is effective for radio-sensitization. Furthermore, the extent of mitochondrial targeting was responsible for sensitization efficiency both in vitro and in vitro. By RNA sequencing technique, the result was ascribed to the reactive oxygen species (ROS) mediated TNF-JNK pathway and cell cycle arrest besides breaking DNA, in contrast to only DNA damage only with those untargeted nanoparticles. Our work indicated that ROS generated by the irradiation can be utilized by activating an alternative apoptotic pathway with mitochondrial targeting nanoparticles, and therefore may suggest an approach for the enhancement of radio-sensitization. Radiosensitization by nanoparticles could reduce the burden of cancer due to lowering the dose of radiation therapy and reducing side-effect. How to fully utilize the interactions of irradiation-nanoparticles-biotissues remains a challenge for improving the outcome of radiosensitization. In this manuscript, by modifying tumor-targeting and mitochondria-targeting ligands on nanoparticles, separately and jointly, we demonstrated that the radiosensitization efficiency of NaGdF 4 :Yb,Er nanoparticle depends on the extent of accumulation near mitochondria. By RNA-seq technique, the RT sensitization with mitochondrial targeting was ascribed to ROS-mediated TNF-JNK pathway and cell cycle arrest, in contrast to only DNA breaks with untargeted nanoparticles. The results suggested a strategy for better utilization of the energy of therapeutic irradiation and demonstrate that subcellular targeting is a potent factor for designing nanoparticulate radiosensitizers. [Display omitted] [ABSTRACT FROM AUTHOR]

Uptake and intracellular trafficking of nanoparticles are tightly regulated by their interactions with cellular organelles and physiological microenvironment. Although the dynamic physicochemical reactions at the interface of nanoparticles and cells ultimately determine the intracellular distribution and fate, microscopic tracing and quantitative analysis of the nanoparticles have been hampered by the limited resolution associated with individual nanoparticle trafficking. Herein, we report spatiotemporal investigations on autophagic clearance of biodegradable iron oxide-silica core-shell nanoparticles in terms of intracellular trafficking and ionic dissolution at a single cell level using multimodal imaging systems. By combining transmission electron microscopy and super-resolution confocal laser scanning microscopy with fluorescence correlation spectroscopy, the complementary imaging analysis exclusively shows the intracellular uptake, endosomal fusion and biodegradative clearance, leading to identify the step-by-step endocytic transport pathway and autophagic degradation pathways. Tracing the intracellular trafficking of nanoparticles reveals that they are spontaneously transported from endosomes to lysosomes, and transiently stimulate autophagy while maintaining cell viability. While protecting iron oxide core, the silica shell is gradually degraded during endocytosis and autophagic clearance, resulting in ionic dissolution of iron oxide in acidic environment. Moreover, burst reduction of ferric ions by adding ascorbic acid readily triggers acute ferroptosis owing to rapid supplement of ferrous ions and Fenton reaction in cancer cells. The complementary imaging strategy provides insights into the design of biocompatible nanomedicines for cellular delivery and the degradative mechanisms beyond the intracellular fate. [Display omitted] • Complementary imaging enables systematic investigations of intracellular trafficking of nanoparticles at single cell-level. • Upon endocytic uptake, a few freely-diffusing nanoparticles are observed, but ultimately merged to endosomal vesicles. • Biodegradable silica shell of the nanoparticle is cleared through autophagy formation in perinuclear region within 24 hr. • Acute ferroptosis is readily triggered by burst reduction of ferric ions released from iron oxide nanoparticles with ascorbic acid. [ABSTRACT FROM AUTHOR]

Nowadays, microRNA is considered an attractive strategy for the effective treatment of cancer. A significant delivery of microRNA for cancer therapy remains a significant obstacle to target cancer cells. The restoring microRNA-1296 (miR-1296) has immense therapeutic efficacy in triple-negative breast cancer (TNBC). TNBC is an aggressive subtype of breast tumors with the progression of malignant transformation. This study aimed to develop a cationic nanoliposome that can serve as a miR-1296 carrier and studied its efficiency in TNBC. The efficacy of miR-1296 liposomes was evaluated on its apoptotic effect, cellular uptake, and potential chemotherapy sensitization in the TNBC cell line (MDA-MB-231). For in vitro viability study, the apoptotic effect was performed to validate protein expression using Alamar blue kit and western blot. The transfection of miR-1296 into TNBC cells was also investigated using cisplatin as a TNBC resistance drug. The fluorescent miR-1296-cy3 liposome was used for cellular uptake study. The miR-liposome was successfully prepared with a particle size of 123.6 ± 1.3 nm and encapsulation efficiency of 94.33%. A dose of 0.5 uM has significantly reduced the viability of MDA-MB-231 to be 33.45%±5.29 (P < 0.001). This result was validated by down-expression of CCND1, and PARP1, the miR-1296 receptor, and apoptosis marker. The image of the miR-1296-cy3 liposome showed cytoplasmic intracellular localization. It was found high sensitization of TNBC cell line for miR-1296 liposome compared to cisplatin (P < 0.001). Future in vivo research may answer questions concerning safety and stability. This study demonstrates that miR-191 liposomes may have promising clinical applications for TNBC therapy. [ABSTRACT FROM AUTHOR]

Current advances of immunotherapy have greatly changed the way of cancer treatment. At the same time, a great number of nanoparticle-based cancer immunotherapies (NBCIs) have also been explored to elicit potent immune responses against tumors. However, few NBCIs are nearly in the clinical trial which is mainly ascribed to a lack understanding of in vivo fate of nanoparticles (NPs) for cancer immunotherapy. NPs for cancer immunotherapy mainly target the immune organs or immune cells to enable efficient antitumor immune responses. The physicochemical properties of NPs including size, shape, elasticity and surface properties directly affect their interaction with immune systems as well as their in vivo fate and therapeutic effect. Hence, systematic analysis of the physicochemical properties and their effect on in vivo fate is urgently needed. In this review, we first recapitulate the fundamentals for the in vivo fate of NBCIs including physio-anatomical features of lymphatic system and strategies to modulate immune responses. Moreover, we highlight the effect of physicochemical properties on their in vivo fate including lymph nodes (LNs) drainage, cellular uptake and intracellular transfer. Challenges and opportunities for rational design of NPs for cancer immunotherapy are also discussed in detail. Physicochemical properties including size, shape, elasticity, surface charge and surface ligand influence the in vivo fate of NBCIs, including LNs drainage, cellular uptake and intracellular transfer. [Display omitted] [ABSTRACT FROM AUTHOR]

Exosomes (extracellular vesicles/EVs) participate in cell–cell communication and contain bioactive molecules, such as microRNAs. However, the detailed characteristics of secreted EVs produced by cells grown under low pH conditions are still unknown. Here, we report that low pH in the cell culture medium significantly affected the secretion of EVs with increased protein content and zeta potential. The intracellular expression level and location of stably expressed GFP‐fused CD63 (an EV tetraspanin) in HeLa cells were also significantly affected by environmental pH. In addition, increased cellular uptake of EVs was observed. Moreover, the uptake rate was influenced by the presence of serum in the cell culture medium. Our findings contribute to our understanding of the effect of environmental conditions on EV‐based cell–cell communication. [ABSTRACT FROM AUTHOR]

In this paper, Doxil coupled with anti-CD133 monoclonal antibodies made by either routine or optimized post-insertion technique, were compared with respect to their size, drug leakage, release pattern and the number of antibodies conjugated per single liposome. The results demonstrated that the number of antibodies conjugated per liposome in the optimized post-insertion technique was almost two times more than those in the routine post-insertion method. However, the drug release and leakage pattern was almost similar between the two methods. Furthermore, anti-tumor activity and therapeutic efficacy of the preferred CD133–targeted Doxil with Doxil was compared in terms of their in vitro binding, uptake, internalization and cytotoxicity against HT-29 (CD133+) and CHO (CD133-) cells. Flow cytometry analyses and confocal laser scanning microscopy results exhibited a significantly higher cellular uptake, binding and internalization of CD133-targeted Doxil in CD+133 cells relative to Doxil. Cytotoxicity results revealed a lower in vitro inhibitory concentration for CD133–targeted Doxil compared to Doxil. However, CHO (CD133-) cells displayed a similar uptake and in vitro cytotoxicity for both CD133-Doxil and non-targeted Doxil. Therefore, the results of this study can exhibit that specific recognition and binding of antibodies with CD133 receptors on HT-29 cells can result in enhanced cellular uptake, internalization and cytotoxicity. The research suggests further investigation for in vivo studies and may offer proof-of-principle for an active targeting concept. [ABSTRACT FROM AUTHOR]

The reduction of survival motor neuron (SMN) protein causes spinal muscular atrophy (SMA), an autosomal recessive neuromuscular disease. Nusinersen is an antisense oligonucleotide, approved by the FDA, which specifically binds to the repressor within SMN2 exon 7 to enhance exon 7 inclusion and augment production of functional SMN protein. Nusinersen is the first new oligonucleotide- based drug targeting the central nervous system for the treatment of SMA. This review of nusinersen will discuss its action mechanism, cellular uptake, trafficking mechanisms, and administration approaches to cross the blood-brain barrier. Furthermore, nusinersen clinical trials will be assessed in terms of pharmacokinetics, tolerability and safety, the clinical outcomes of multiple intrathecal doses, and a discussion on the primary and secondary endpoints. [ABSTRACT FROM AUTHOR]

Nano-sized objects such as liposomes are modified by adsorption of biomolecules in biological fluids. The resulting corona critically changes nanoparticle behavior at cellular level. A better control of corona composition could allow to modulate uptake by cells. Within this context, in this work, liposomes of different charge were prepared by mixing negatively charged and zwitterionic lipids to different ratios. The series obtained was used as a model system with tailored surface properties to modulate corona composition and determine the effects on liposome interactions with cells. Uptake efficiency and uptake kinetics of the different liposomes were determined by flow cytometry and fluorescence imaging. Particular care was taken in optimizing the methods to isolate the corona forming in human serum to prevent liposome agglomeration and to exclude residual free proteins, which could confuse the results. Thanks to the optimized methods, mass spectrometry of replicate corona isolations showed excellent reproducibility and this allowed semi-quantitative analysis to determine for each formulation the most abundant proteins in the corona. The results showed that by changing the fraction of zwitterionic and charged lipids in the bilayer, the amount and identity of the most abundant proteins adsorbed from serum differed. Interestingly, the formulations also showed very different uptake kinetics. Similar approaches can be used to tune lipid composition in a systematic way in order to obtain formulations with the desired corona and cell uptake behavior. Liposomes and other nano-sized objects when introduced in biological fluids are known to adsorb biomolecules forming the so-called nanoparticle corona. This layer strongly affects the subsequent interactions of liposomes with cells. Here, by tuning lipid composition in a systematic way, a series of liposomes with tailored surface properties has been prepared to modulate the corona forming in human serum. Liposomes with very different cellular uptake kinetics have been obtained and their corona was identified in order to determine the most enriched proteins on the different formulations. By combining corona composition and uptake kinetics candidate corona proteins associated with reduced or increased uptake by cells can be identified and the liposome formulation can be tuned to obtain the desired uptake behavior. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Understanding interactions between nanoparticles and model membranes is relevant to functional nano-composites and the fundamentals of nanotoxicity. In this study, the effect of polyamidoamine (PAMAM) dendrimers as model nanoparticles (NP) on the mesophase behaviour of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) has been investigated using high-pressure small-angle X-ray scattering (HP-SAXS). The pressure-temperature (p − T) diagrams for POPE mesophases in excess water were obtained in the absence and presence of G2 and G4 polyamidoamine (PAMAM) dendrimers (29 Å and 45 Å in diameter, respectively) at varying NP-lipid number ratio (ν = 0.0002–0.02) over the pressure range p = 1–3000 bar and temperature range T = 20–80 °C. The p − T phase diagram of POPE exhibited the L β , L α and H II phases. Complete analysis of the phase diagrams, including the relative area pervaded by different phases, phase transition temperatures (T t) and pressures (p t), the lattice parameters (d -spacing), the pressure-dependence of d -spacing (Δ d /Δ p), and the structural ordering in the mesophase as gauged by the Scherrer coherence length (L) permitted insights into the size- and concentration-dependent interactions between the dendrimers and the model membrane system. The addition of dendrimers changed the phase transition pressure and temperature and resulted in the emergence of highly swollen lamellar phases, dubbed L β-den and L α-den. G4 PAMAM dendrimers at the highest concentration ν = 0.02 suppressed the formation of the H II phase within the temperature range studied, whereas the addition of G2 PAMAM dendrimers at the same concentration promoted an extended mixed lamellar region in which L α and L β phases coexisted. Using high pressure small angle X-ray scattering in the pressure range 1–3000 bar and temperature range 20–60 °C, we have studied interactions between PAMAM dendrimers (as model nanoparticles) and POPE lipid mesophases (as model membranes). We report the pressure-temperature phase diagrams for the dendrimer-lipid mesophases for the first time. We find that the dendrimers alter the phase transition temperatures (T t) and pressures (p t), the lattice parameters (d -spacing), and the structural order in the mesophase. We interpret these unprecedented results in terms of the fluidity of the lipid membranes and the interactions between the dendrimers and the membranes. Our findings are of fundamental relevance to the field of nanotoxicity and functional nanomaterials that integrate nanoparticles and organized lipid structures. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Surface modification to obtain high dispersion stability and biocompatibility is a key factor for bio-application of upconversion nanoparticles (UCNPs). A systematic study of UCNPs modified with four hydrophilic molecules separately, comparing their dispersion stability in biological buffers and cellular biocompatibility is reported here. The results show that carboxyl-functionalized UCNPs (modified by 3,4-dihydrocinnamic acid (DHCA) or poly(monoacryloxyethyl phosphate (MAEP)) with negative surface charge have superior even-distribution in biological buffers compared to amino-functionalized UCNPs (modified by (aminomethyl)phosphonic (AMPA) or (3-Aminopropyl)triethoxysilane (APTES)) with positive surface charge. Subsequent investigation of cellular interactions revealed high levels of non-targeted cellular uptake of the particles modified with either of the three small molecules (AMPA, APTES, DHCA) and high levels of cytotoxicity when used at high concentrations. The particles were seen to be trapped as particle-aggregates within the cellular cytoplasm, leading to reduced cell viability and cell proliferation, along with dysregulation of the cell cycle as assessed by DNA content measurements. The dramatically reduced proportion of cells in G 1 phase and the slightly increased proportion in G 2 phase indicates inhibition of M phase, and the appearance of sub-G 1 phase reflects cell necrosis. In contrast, MAEP-modified UCNPs are bio-friendly with increased dispersion stability in biological buffers, are non-cytotoxic, with negligible levels of non-specific cellular uptake and no effect on the cell cycle at both low and high concentrations. MAEP-modified UCNPs were further functionalized with streptavidin for intracellular microtubule imaging, and showed clear cytoskeletal structures via their upconversion luminescence. Upconversion nanoparticles (UCNP) are an exciting potential nanomaterial for bio-applications. Their anti-Stokes luminescence makes them especially attractive to be used as imaging probes and thermal therapeutic reagents. Surface modification is the key to achieving stable and compatible hydrophilic-UCNPs. However, the lack of criteria to assess molecular ligands used for ligand exchange of nanoparticles has hampered the development of surface modification, and further limits UCNP's bio-application. Herein, we report a systematic comparative study of modified-UCNPs with four distinct hydrophilic molecules, assessing each particles' colloidal stability in biological buffers and their cellular biocompatibility. The protocol established here can serve as a potential guide for the surface modification of UCNPs in bio-applications. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The present study focused on the bioaccumulation and cytotoxicities of Cd2+, CdSe quantum dots (QDs) and CdSe/ZnS QDs in Escherichia coli (E. coli , represents prokaryotic system) and Phanerochaete chrysosporium (P. chrysosporium , represents eukaryotic system), respectively. Two types of QDs were characterized by transmission electron microscopy (TEM) and dynamic light scattering. The inductively coupled plasma optical emission spectrometer results showed that the bioaccumulation amounts of CdSe QDs by E. coli and P. chrysosporium were larger than those of CdSe/ZnS QDs due to the smaller particle size and less negative surface charges of CdSe QDs. Confocal microscopy and TEM results showed that there was an interaction between QDs and cells, and QDs have entered into the cells eventually, leading to the change of cell morphology. Plasma membrane fluidities and membrane H+-ATPase activities of E. coli and P. chrysosporium decreased gradually with the increasing concentrations of Cd2+, CdSe and CdSe/ZnS QDs. Results of the cell viabilities and intracellular reactive oxygen species levels indicated that the induced cytotoxicities were decreased as follows: CdSe QDs > CdSe/ZnS QDs > Cd2+. These findings suggested that the cytotoxicity of QDs was not only attributed to their heavy metal components, but also related to their nanosize effects which could induce particle-specific toxicity. The above results offer valuable information for exploring the cytotoxicity mechanism of QDs in prokaryote and eukaryote. Image 1 • CdSe QDs were more easily absorbed by cells as compared to CdSe/ZnS QDs. • P. chrysosporium was more sensitive to Cd2+, CdSe and CdSe/ZnS QDs than E. coli. • The intracellular ROS level was dependent on the intracellular concentration of QDs. [ABSTRACT FROM AUTHOR]

PEGylation strategy has been widely used to enhance colloidal stability of polycation/DNA nanoparticles (NPs) for gene delivery. To investigate the effect of polyethylene glycol (PEG) terminal groups on the transfection properties of these NPs, we synthesized DNA NPs using PEG- g -linear polyethyleneimine (l PEI) with PEG terminal groups containing alkyl chains of various lengths with or without a hydroxyl terminal group. For both alkyl- and hydroxyalkyl-decorated NPs with PEG grafting densities of 1.5, 3, or 5% on l PEI, the highest levels of transfection and uptake were consistently achieved at intermediate alkyl chain lengths of 3 to 6 carbons, where the transfection efficiency is significantly higher than that of nonfunctionalized l PEI/DNA NPs. Molecular dynamics simulations revealed that both alkyl- and hydroxyalkyl-decorated NPs with intermediate alkyl chain length exhibited more rapid engulfment than NPs with shorter or longer alkyl chains. This study identifies a new parameter for the engineering design of PEGylated DNA NPs. The effect of PEG terminal groups in the interactions of PEGylated DNA nanoparticles with cells is investigated through an integrated experimental and computational approach. For nanoparticles with alkyl/hydroxyalkyl PEG terminal group, the highest transfection efficiency and cellular uptake levels occur at intermediate alkyl chain length. Subtle changes in PEG terminal groups significantly affect gene expression and cellular uptake levels. Unlabelled Image [ABSTRACT FROM AUTHOR]

Delivery matrices in foods need to be carefully designed for optimal delivery and to ensure that beneficial compounds are subsequently absorbed in the gut. It has been found that polysaccharide coating improved the cellular uptake of liposomes, but there is a lack of research on the effect of digestion on the cellular uptake of polysaccharide-coated liposomes. Herein, the sodium alginate-coated liposomes were prepared, combination of Caco-2, HT29 and Caco-2/HT29 cell models were used to assess the effect of digestion behavior on the bioavailability. Where, the bioavailability of digested liposomes was 1.60 times higher than that of undigested liposomes. Specifically, digestion firstly improved the ability of liposomes to penetrate the mucus layer by 1.43-fold. Secondly, digestion improved the uptake of liposomes into the intestinal cells by about 1.33-fold. Next, cellular uptake mechanisms were explored using uptake inhibition experiments. Proteomics and metabolic process experiments showed that liposomes pass intact through the small intestinal epithelium into the somatic circulation. This work suggested that digestive behavior enhanced liposome bioavailability in terms of penetration through the cellular mucus layer as well as uptake capacity. These results deepen the understanding of the specific role of digestion on polysaccharide-modified liposomes and favor a better design of delivery systems. [Display omitted] • Digested SA-CP-Lip could successfully transport through the Caco-2/HT29 model. • Digestion improves cellular uptake of SA-CP-Lip. • The absorption of SA-CP-Lip was dominated by endocytosis of reticulin and caveolin. • Digested SA-CP-Lip could across the mucus layer of small intestinal epithelial cells. • Digested SA-CP-Lip might enter the humoral circulation. [ABSTRACT FROM AUTHOR]

Highlights • Surface coating affects cytotoxicity of silver nanoparticles (AgNP) in neural stem cells. • Surface coating has impact on uptake efficiency of AgNP into neural stem cells. • All AgNP demonstrated dose response effects. • All AgNP were taken up by macropinocytosis. Abstract The rapid development and widespread applications of nanotechnology necessitates the design towards safe nanoparticles. Surface structure is among the most important physicochemical characteristics of metallic nanoparticles affecting their mode of action in certain biological or environmental compartments. This study aimed to investigate how different surface coatings affect the cytotoxicity and cellular uptake of silver nanoparticles (AgNPs) in murine neural stem cells (mNSCs). Different AgNPs were prepared by stabilisation with surface coatings encompassing sodium bis(2-ethylhexyl)-sulfosuccinate (AOT), cetyltrimethylammonium bromide (CTAB), poly(vinylpyrrolidone) (PVP), poly- l -lysine (PLL), and bovine serum albumin (BSA). The obtained results revealed that AgNPs stabilized with different surface coating caused different cytotoxicity effects and internalization pattern in mNSCs. Macropinocytosis was determined as the main uptake mechanism in mNSCs for all of the tested AgNP types. These findings contribute to the overall knowledge essential to the safety assessment of novel nanomaterials. [ABSTRACT FROM AUTHOR]

Abstract Humans are likely exposed to cadmium sulfide nanomaterials (CdS NMs) due to the increasing environmental release and in vivo application of these materials, which tend to accumulate and cause toxic effects in human lungs, particularly by interrupting the physiological functions of macrophage cells. Here, we showed that protein corona played an essential role in determining cellular uptake and cytotoxicity of CdS NMs in macrophages. Protein-coated CdS NMs enhanced the expression of FcγRIIB receptors on the cell surface, and the interaction between this receptors and proteins inhibited cellular uptake of CdS NMs while triggering cell apoptosis via the AKT/Caspase 3 signaling pathway. Cytotoxicity of CdS NMs was greatly alleviated by coating the nanomaterials with polyethylene glycol (PEG), because PEG decreased the adsorption of proteins that interact with the FcγRIIB receptors on cell surface. Overall, our research demonstrated that surface modification, particularly protein association, significantly affected cellular response to CdS NMs, and cellular uptake may not be an appropriate parameter for predicting the toxic effects of these nanomaterials in human lungs. Graphical abstract fx1 Highlights • Protein corona determined the cellular uptake and cytotoxicity of nano-CdS in lungs. • Protein-coated nano-CdS enhanced expression of FcγRIIB receptor on the cell surface. • Protein-receptor interaction triggered the AKT/Caspase 3 pathway of cell apoptosis. • Cytotoxicity may not be predicted by cellular uptake of nano-CdS in lung cells. [ABSTRACT FROM AUTHOR]

Abstract The delivery of nanoparticles through receptor-mediated cell interactions has nowadays a major attention in the area of drug targeting applications. This specific kind of targeting is mediated by localized receptors impeded into the target site with subsequent drugs internalization. Hence, this type of interaction would diminish side effects and enhance drug delivery efficacy to the target site. Somatostatin receptors (SSTRs) are one type of G protein-coupled receptors, which could be active targeted for various purposes. There are five SSTRs types (SSTR1-5) which are localized at various organs in the body and spread into different tissues. SSTRs could be considered as a promising target to various nanoparticles which is facilitated when nanoparticles are modified through specific ligand or coating to allow better binding. This review discusses the exploration of SSTRs for active targeting of nanoparticles with certain emphasize on their interaction at the cellular level. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Poly(ethylene glycol) (PEG) has been extensively used to coat the surface of nanocarriers to improve their physicochemical properties and allow the grafting of targeting moieties. Still, to date there is no common agreement on the ideal PEG coverage-density or length to be used for optimum vector performance. In this study, we aimed to investigate the impact of both PEG density and length on the vectoring capacity of neuron-targeted gene-carrying trimethyl chitosan nanoparticles. The non-toxic fragment from the tetanus toxin (HC) was coupled to a 5 kDa heterobifunctional PEG (HC-PEG 5k) reactive for the thiol groups inserted into the polymer backbone and grafted at different densities onto the nanoparticles. Internalization and transfection studies on neuronal versus non-neuronal cell lines allowed to determine the PEG density of 2 mol% of PEG chains per mol of primary amine groups as the one with superior biological performance. To enhance HC exposure and maximize cell-nanoparticle specific interaction, NPs containing different ratios of HC-PEG 5k and 2 kDa methoxy-PEG at the same grafting density were produced. By intercalating HC-PEG 5k with methoxy-PEG 2k we attained the best performance in terms of internalization (higher payload delivery into cells) and transfection efficiency, using twice lower amount of HC. This outcome highlights the need for fine-tuning of PEG-modified nanoparticles towards the achievement of optimal targeting. Statement of Significance The amount and exposure of targeting moieties at a nanoparticle surface are critical parameters regarding the targeting potential of nanosized delivery vectors. However, to date, few studies have considered fundamental aspects impacting the ligand-receptor pair interaction, such as the effect of spacer chain length, flexibility or conformation. By optimizing the PEG spacer density and chain length grafted into nanoparticles, we were able to establish the formulation that maximizes cell-nanoparticle specific interaction and has superior biological performance. Our work shows that the precise adjustment of the PEG coverage-density presents a significant impact on the selectivity and bioactivity of the developed formulation, emphasizing the need for the fine-tuning of PEG-modified nanoparticles for the successful development of the next-generation nanomedicines. [ABSTRACT FROM AUTHOR]

Graphical abstract Schematic form of the proposed mechanisms for CLA and CLB induced apoptosis in SGC-7901 cells. CLA, [1–9-NαC]-linusorb B3; CLB, [1–9-NαC]-linusorb B2. Highlights • [1–9-NαC]-linusorb B3 showed higher absorption than [1–9-NαC]-linusorb B2. • [1–9-NαC]-linusorb B3 induced more obvious apoptosis on SGC-7901 cells than [1–9-NαC]-linusorb B2. • Both intrinsic and extrinsic pathway might be involved in [1–9-NαC]-linusorb B3-induced apoptosis. • Extrinsic pathway might be involved in [1–9-NαC]-linusorb B2-induced apoptotic process. Abstract The aim of this study was to investigate the cellular uptake and antitumor activity of 2 different structural flaxseed orbitides ([1–9-NαC]-linusorb B2 containing methionine residue and [1–9-NαC]-linusorb B3 containing isoleucine residue) in SGC-7901 cells as well as its underlying molecule mechanism. Results showed that the absorption efficiency of [1–9-NαC]-linusorb B3 was higher than that of [1–9-NαC]-linusorb B2. Besides, through the evaluation of mitochondrial membrane potential (Δφm), cytochrome c (Cyt C) release, caspase, death receptor activation and cleavage of PARP, we found that [1–9-NαC]-linusorb B3 exhibited more obvious apoptosis induction on SGC-7901 cells than [1–9-NαC]-linusorb B2. Interestingly, [1–9-NαC]-linusorb B3-induced cell apoptosis might involve a mitochondrial- and death receptor-mediated intrinsic and extrinsic pathway; however, [1–9-NαC]-linusorb B2 induced cell apoptosis by the activation of Fas, FasL, caspase 8 as well as caspase 3 instead of Bax, Cyt C , tBid and caspase 9, suggesting that extrinsic pathway might be involved in the apoptotic process. [ABSTRACT FROM AUTHOR]

The interaction of nanocarriers with blood plasma components influences the biological response, and therefore, it needs to be controlled. Whereas protein adsorption to nanocarriers has been investigated to a large extent, the role of lipid interaction for drug delivery and its biological effect is not yet clear. However, lipids represent an important constituent of blood plasma and are usually bound in the form of lipoproteins. Because already for many nanocarrier systems an enrichment of apolipoproteins in their protein corona was reported, we examine the interaction of lipoproteins with nanocarriers. If interaction occurs in terms of lipoprotein adsorption, two scenarios are possible: adsorption of intact lipoprotein complexes or disintegration of the complexes with adsorption of the single components. To investigate the interaction and clarify which scenario occurs, polymeric model nanoparticles and different lipoprotein types have been studied by isothermal titration calorimetry, transmission electron microscopy, and other methods. Our data indicate that upon contact with polymeric nanoparticles, disintegration of lipoproteins and adsorption of lipids occurs. Further, the effect of lipoprotein adsorption on cell uptake has been examined, and a major effect of the lipoproteins has been found. Statement of Significance It is now well accepted that nanomaterials developed as diagnostic or therapeutic carrier systems need to be well characterized in terms of biological responses inside an organism. Many studies have already shown that proteins adsorb to the surface of a nanomaterial and create a new interface that define the identity of the material. However, the presence of other surface-active components of the blood plasma and how they interact with nanomaterials has been much less investigated. Thus, this study aims at providing a significant contribution to understanding the interaction mechanism between lipoproteins and nanomaterials. Since lipoproteins transport a high amount of lipids, which are surface-active molecules, the demonstrated interactions can go as far as complete lipoprotein disintegration. [ABSTRACT FROM AUTHOR]

Plastics have been used for about 100 years, and daily-use products composed of plastics are now prevalent. As a result, humans are very easily exposed to the plastic particles generated from the daily-use plastics. However, studies on cellular uptake of nanoplastics in "human cells" have only recently begun to attract attention. In previous studies, definitions of nanoplastics and microplastics were vague, but recently, they have been considered to be different and are being studied separately. However, nanoplastics, unlike plastic particles of other sizes such as macro- and microplastics, can be absorbed by human cells, and thus can cause various risks such as cytotoxicity, inflammation, oxidative stress, and even diseases such as cancer82, 83. and diabetes (Fan et al., 2022; Wang et al., 2023). Thus, in this review, we defined microplastics and nanoplastics to be different and described the potential risks of nanoplastics to human caused by cellular uptake according to their diverse factors. In addition, during and following plastic product usage a substantial number of fragments of different sizes can be generated, including nanoplastics. Fragmentation of microplastics into nanoplastics may also occur during ingestion and inhalation, which can potentially cause long-term hazards to human health. However, there are still few in vivo studies conducted on the health effect of nanoplastics ingestion and inhalation. [Display omitted] • Continuous exposure of microplastics may pose health risk through cellular uptake. • Nanoplastics can be readily generated by the in vivo fragmentation of microplastics. • The cellular uptake mechanism of the diverse factors of nanoplastics is reviewed. • Studies on the nanoplastics are still insufficient and need to be further explored. [ABSTRACT FROM AUTHOR]

Melanoidins make the major contribution to the antioxidative activity (AA) of vinegar. Elucidation on partial groups vital to AA helps to positively control the AA of vinegar melanoidins without suffering from thorough structural revelation of melanoidins. The melanoidin bound compounds (MBC) that are non-covalently attached to the melanoidin skeletons contribute to 89% of the cellular antioxidant activity of vinegar melanoidins, where modification by digestion and cellular uptake are no longer overlooked. MBC contains a respectable amount of phenolics and renders at least 85% of the proximal-gastrointestinal-tract bioavailable phenolics attributable to vinegar melanoidins, as evidenced by LC-MS 2 analysis of cellular uptake and trans-enterocyte transport. We propose that MBC play a determinant role in the AA of vinegar melanoidins and thus could serve as a target to optimise the AA of vinegar melanoidins and even of vinegar. [ABSTRACT FROM AUTHOR]

Knowledge of delivery system transport through epidermal cell monolayer is vital to improve skin permeation and bioavailability. Recently, nanostructured lipid carriers (NLCs) have gained great attention for transdermal delivery due to their biocompatibility, high drug payload, occlusive properties and skin hydration effect. However, the nanocarriers transport related mechanisms in epidermal epithelial cells are not yet understood. In this research, the internalization and transport pathways of the NLCs across the epidermal epithelial cell monolayer (HaCaT cells) were investigated. The 250 nm sized witepsol/miglyol NLCs, prepared by hot homogenization had reduced cytotoxicity and no effect on the integrity of cell membrane in human HaCaT keratinocytes. The internalization was time-, concentration- and energy-dependent, and the uptake of NLCs was a vesicle-mediated process by macropinocytosis and clathrin-mediated pathways. 3% of NLCs were found at the apical membrane side of the HaCaT monolayer through exocytosis mechanism. Additionally, the endoplasmic reticulum, Golgi apparatus and microtubules played crucial roles in the transport of NLCs out of HaCaT cells. NLCs were transported intact across the human keratinocytes monolayer, without disturbing the tight junction’s structure. From the transcytosis data only approximately 12% of the internalized NLCs were passed from the apical to the basolateral side. The transcytosis of NLCs throughout the HaCaT cell monolayer towards the basolateral membrane side requires the involvement of the endoplasmic reticulum, Golgi apparatus and microtubules. Our findings may contribute to a systematic understanding of NLCs transport across epidermal epithelial cell monolayers and their optimization for clinical transdermal application. Statement of Significance Transdermal drug delivery is a challenging and growing area of clinical application. Lipid nanoparticles such as nanostructured lipid carriers (NLCs) have gained wide interest for transdermal drug delivery. However these nanocarriers’ interactions with epidermal epithelial barrier are yet unknown. Unveiling the mechanisms involved in NLCs transport across the epidermal epithelial monolayers will contribute with valuable information to achieve enhanced skin permeability, superior bioavailability and consequently improved therapeutic effect. With our present work we could certainly provide researchers and clinicians guidance for the design of optimized transdermal delivery systems, based on the nanomaterials and biological interactions. [ABSTRACT FROM AUTHOR]

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The ability of exosomes to elicit specific cellular responses suggests that they may be increasingly used as therapeutics. Their vesicular nature makes them suitable as potential nanocarriers for drugs or nucleic acids delivery. Here we address the question whether the method of preparation of enriched exosomal fractions can affect their uptake by cells and their ability to trigger a response. We compared ultracentrifugation and polymer-based precipitation methods on supernatants of glioma-associated stem cells isolated from a high-grade glioma patient. We determined particle size distributions after purification and their correlation with uptake, proliferation and migration in glioblastoma cell cultures. Our findings indicate that polymer-based precipitation leads to smaller particle size distributions, faster uptake by target cells and increased cellular motility. The different effect that isolation method-dependent populations of particles have on cell motility suggests their size distribution could also profoundly affect exosomes therapeutic potential. [ABSTRACT FROM AUTHOR]

Differentiation of stem cells is influenced by many factors, yet uptake of the magnetic particles with or without magnetic field is rarely tackled. In this study, iron oxide nanoparticles-loaded bovine serum albumin (BSA) (Fe 3 O 4 /BSA) particles were prepared, which showed a spherical morphology with a diameter below 200 nm, negatively charged surface, and tunable magnetic property. The particles could be internalized into bone marrow mesenchymal stem cells (MSCs), and their release from the cells was significantly retarded under external magnetic field, resulting in almost twice intracellular amount of the particles within 21 d compared to that of the magnetic field free control. Uptake of the Fe 3 O 4 /BSA particles enhanced significantly the osteogenic differentiation of MSCs under a static magnetic field, as evidenced by elevated alkaline phosphatase (ALP) activity, calcium deposition, and expressions of collagen type I and osteocalcin at both mRNA and protein levels. Therefore, uptake of the Fe 3 O 4 /BSA particles brings significant influence on the differentiation of MSCs under magnetic field, and thereby should be paid great attention for practical applications. Statement of Significance Differentiation of stem cells is influenced by many factors, yet uptake of the magnetic particles with or without magnetic field is rarely tackled. In this study, iron oxide nanoparticles-loaded bovine serum albumin (BSA) (Fe 3 O 4 /BSA) particles with a diameter below 200 nm, negatively charged surface, tunable Fe 3 O 4 content and subsequently adjustable magnetic property were prepared. The particles could be internalized into bone marrow mesenchymal stem cells (MSCs), and their release from the cells was significantly retarded under external magnetic field. Uptake of the Fe 3 O 4 /BSA particles enhanced significantly the osteogenic differentiation of MSCs under a constant static magnetic field, while the magnetic particles and external magnetic field alone do not influence significantly the osteogenic differentiation potential of MSCs regardless of the uptake amount. The results demonstrate a potential magnetic manipulation method for stem cell differentiation, and also convey the significance of careful evaluation of the safety issue of magnetic particles in real an application situation. [ABSTRACT FROM AUTHOR]

Using assistant reagents to improve the pharmaceutical performance of cisplatin (CDDP) has been one of promising strategies. Owing to their extraordinary properties, graphene quantum dots (GQDs) have shown great potentials in biomedical applications. Here we demonstrate that the combination of GQDs with CDDP can effectively enhance the cytotoxicity, cell cycle arrest, and DNA fragmentation that induced by CDDP. We also found that the GQDs improved the interaction of CDDP with DNA. Combing these results with our previous finding that graphene oxide could enhance the permeability of the cells, we believe GQDs improve the pharmaceutical performance of CDDP via first increasing its cellular uptake through improving the cell permeability, and then reinforcing its interaction with DNA once it is inside cells. The remarkable enhancement to CDDP cellular uptake in CDDP resistant cells further specifies that GQDs can increase chemotherapy efficacy of anticancer drugs that are suboptimal due to the drug resistance. [ABSTRACT FROM AUTHOR]

Micelles self-assembled from drug-conjugated polymers indicate advantages in alleviating the premature release before reaching the intended site. Hyaluronic acid (HA) is known to specifically bind with a transmembrane glycoprotein CD44, overexpressed in many types of cancerous cells, and can also be served as micelle carriers. However, an excess amount of drug conjugation to HA backbone may be detrimental to the receptor-mediated cellular uptake. Up to now, the effect of conjugation densities of drugs has never been determined on the physical properties and biological performance of resulting micelles. In the current study, camptothecin (CPT) was conjugated on HA through 3,3′-dithiodipropionic acid to self-assemble into reduction-sensitive micelles. The substitution degrees of CPT on HA backbone were tuned from around 4–20%, to clarify the effects on the cellular uptake efficiency and cytotoxicities of micelles, as well as the tumor accumulation and antitumor efficacy. The CPT substitution degree of around 15% on HA resulted in micelles with a higher cytotoxicity to 4T1 cells and achieved a better balance between the cellular uptake and reduction-triggered drug release, compared with other micelles. In contrast to a fast kidney clearance and an even distribution in major organs after intravenous injection of free CPT, the optimized micelles were accumulated in tumors, livers and lungs. The micelle content indicated a significant decrease in livers after 24 h, while that in tumors displayed a significant increase to 4.9% of the injection dose. The tumor accumulation of micelles led to strong tumor suppression with minimal systemic toxicity. The in situ tumor inhibition and the accumulation of micelles in liver and lungs inhibited tumor metastasis to these tissues. It demonstrates a feasible strategy to develop drug-HA conjugate micelles with a concise and tunable structure for tumor targeting and reduction-triggered release. Statement of Significance Hyaluronic acid (HA) can be served as micelle carriers and targeting ligands to tumor cells. However, the effects of drug conjugation densities on the physical profile and biological performance of resulting micelles have never been investigated. In the current study, camptothecin is conjugated on HA with reduction-sensitive linkers, and the substitution degrees of camptothecin on HA backbone vary from around 4–20%. The micelles with a substitution degree of around 15% achieve a better balance between the cellular uptake and reduction-triggered drug release and a higher cytotoxicity than others. It demonstrates a feasible strategy to develop drug-HA conjugate micelles with a concise and tunable structure for tumor targeting and reduction-triggered release. [ABSTRACT FROM AUTHOR]

Carbon quantum dots (CQDs), unlike semiconductor quantum dots, possess fine biocompatibility, excellent upconversion properties, high photostability and low toxicity. Here, we report multifunctional CQDs which were developed using alginate, 3% hydrogen peroxide and double distilled water through a facile, eco-friendly and inexpensive one-step hydrothermal carbonization route. In this reaction, the alginate served as both the carbon source and the cationization agent. The resulting CQDs exhibited strong and stable fluorescence with water-dispersible and positively-charged properties which could serve as an excellent DNA condensation. As non-viral gene vector being used for the first time, the CQDs showed considerably high transfection efficiency (comparable to Lipofectamine2000 and significantly higher than PEI, p < 0.05) and negligible toxicity. The photoluminescence properties of CQDs also permitted easy tracking of the cellular-uptake. The findings showed that both caveolae- and clathrin-mediated endocytosis pathways were involved in the internalization process of CQDs/pDNA complexes. Taken together, the alginate-derived photoluminescent CQDs hold great potential in biomedical applications due to their dual role as efficient non-viral gene vectors and bioimaging probes. Statement of Significance This manuscript describes a facile and simple one-step hydrothermal carbonization route for preparing optically tunable photoluminescent carbon quantum dots (CQDs) from a novel raw material, alginate. These CQDs enjoy low cytotoxicity, positive zeta potential, excellent ability to condense macromolecular DNA, and most importantly, notably high transfection efficiency. The interesting finding is that the negatively-charged alginate can convert into positively charged CQDs without adding any cationic reagents. The significance of this study is that the cationic carbon quantum dots play dual roles as both non-viral gene vectors and bioimaging probes at the same time, which are most desirable in many fields of applications such as gene therapy, drug delivery, and bioimaging. [ABSTRACT FROM AUTHOR]

To solve the contradiction between long circulation time and effective intracellular drug release, redox and pH-responsive drug delivery system was developed by incorporated redox-sensitive disulfide linkage between poly(amidoamine) dendrimers (PAMAM) and poly(ethylene glycol) (PEG). Doxorubicin (DOX) was loaded into the hydrophobic core of the conjugates to prepare PAMAM-SS-PEG/DOX complexes (PSSP/DOX). In vitro release studies suggested that DOX release from PSSP/DOX complexes followed an redox and acid-triggered manner and increased with increasing PEGylation degree. In vitro cytotoxicity of PSSP/DOX complexes against B16 tumor cells increased with, while cellular uptake decreased with increasing PEGylation degree. Further, intracellular DOX release observation and measurement indicate that the intracellular DOX release played a critical role for the cytotoxicity of DOX-loaded PSSP conjugates. In addition, cellular entry mechanism of the PSSP/DOX study demonstrated that both clathrin- and caveolae-mediated endocytosis were the primary pathways for cellular entry of PSSP/DOX. Finally, in vivo study of PSSP/DOX complexes in B16 tumor-bearing mice indicate that PSSP/DOX could significantly improve antitumor efficiency and present a good safety. The redox and pH-responsive drug delivery system has been demonstrated to be a promising candidate for solid tumor therapy. Statement of Significance In previous research, pH-sensitive diblock polymer of poly(ethylene glycol)-poly(2,4,6-trimethoxybenzylidene-pentaerythritol carbonate) (PEG-PTMBPEC) was synthesized to facilitate the intracellular anticancer drug release. However, the nanoparticles based on PEG-PTMBPEC get into the tumor cells just relying on the EPR-mediated passive targeting resulting in the low drug accumulation. Therefore, cRGD peptide modified PEG-PTMBPEC polymeric micelles were developed for specific targeted delivery of doxorubicin (DOX) to neovascular cells and tumor cells simultaneously. The precise intracellular target site and effective drug concentration will contribute to enhancing the antitumor toxicity and reducing the systematic toxicity of DOX. The cRGD modified pH-sensitive micellar system is a promising vehicle for intracellular drug delivery to αvβ3 integrin receptor overexpressed tumor cells and neovascular cells. [ABSTRACT FROM AUTHOR]

Narrowly dispersed zwitterionic poly(amido amine) (PAA) nanogels with a diameter of approximately 100 nm were prepared by a high-yielding and surfactant-free, inverse nanoprecipitation of PAA polymers. The resulting, negatively charged, nanogels ( PAA-NG1 ) were functionalized with N , N -dimethylethylenediamine via EDC/NHS coupling chemistry. This resulted in nanogels with a positive surface charge ( PAA-NG2 ). Both types of nanogels were fluorescently labelled via isothiocyanate coupling. PAA-NG1 displays high colloidal stability both in PBS and Fetal Bovine Serum solution. Moreover, both nanogels exhibit a distinct zwitterionic swelling profile in response to pH changes. Cellular uptake of FITC-labelled nanogels with RAW 264.7, PC-3 and COS-7 cells was evaluated by fluorescence microscopy. These studies showed that nanogel surface charge greatly influences nanogel–cell interactions. The PAA polymer and PAA-NG1 showed minimal cell toxicity as was evaluated by MTT assays. The findings reported here demonstrate that PAA nanogels possess interesting properties for future studies in both drug delivery and imaging. Statement of significance The use of polymeric nanoparticles in biomedical applications such as drug delivery and imaging, shows great potential for medical applications. However, these nanoparticles are often not stable in biological environments. Zwitterionic polymers have shown excellent biocompatibility, but these materials are not easily degradable in biological environments. With the aim of developing a nanoparticle for drug delivery and imaging we synthesized a biomimetic and readily biodegradable zwitterionic polymer, which was incorporated into nanogels. These nanogels showed excellent stability in the presence of serum and minimal cytotoxicity, which was tested in three cell lines. Because of their negative surface charge and excellent serum stability, these nanogels are therefore promising carriers for drug delivery and molecular imaging. [ABSTRACT FROM AUTHOR]

There is an emerging interest in the applications of luminescent transition metal complexes as biological probes and imaging reagents due to their interesting photophysical properties, which include high photostability, long emission lifetimes, large Stokes' shifts, and highly environment-sensitive emission. The involvement of heavy metal implies that the quantitation of cellular uptake can be conveniently performed by inductively coupled plasma mass spectrometry. For more than a decade, we have developed a number of luminescent transition metal complexes that carry a reactive functional group for bioconjugation. Additionally, we have incorporated different biological substrates within transition metal complexes that show highly environment-sensitive emission and exploited them as noncovalent probes for biomolecules such as nucleic acids and proteins. In the past several years, we have also developed an interest in the cellular studies of related complexes. Different functional moieties have been appended to luminescent transition metal complexes with a variety of spacer-arms to afford new cellular reagents. The functional moieties include biotin, indole, estradiol, alkyl and fluorous chains, intercalating units, dendritic skeleton, reactive functional groups such as isothiocyanate and aldehyde, ion and molecule sensing units, polymeric chains such as poly(ethylene glycol) and poly(ethyleneimine), carbohydrates, and chemical probes for bioorthogonal labeling. In this chapter, we have summarized the molecular design and photophysical properties of a selection of these metal complexes developed in our laboratory. The cellular uptake, cytotoxicity, intracellular trafficking and localization, and the potential biological applications (such as sensing, bioimaging, and photoinduced cytotoxicity) of these complexes have been described. [ABSTRACT FROM AUTHOR]

It is acknowledged that physico-chemical features of nanoparticles have a major impact on their uptake, and especially their surface charge. A widespread observation is that positively charged nanoparticles are more uptaken by cells than neutral or negatively charged nanoparticles. The reason commonly evoked is the favorable electrostatic interactions with negatively charged cell membrane. However, this explanation seems simplistic as it does not take into account a fundamental element: the nanoparticle protein corona. This adds a new level of complexity in the interactions with biological systems that cannot be any more limited to electrostatic binding. [ABSTRACT FROM AUTHOR]

Monodisperse spherical silica nanoparticles (SNPs) with diameters of 20–200 nm were employed to study size, dose, and cell-type dependent cytotoxicity in A549 and HepG2 epithelial cells and NIH/3T3 fibroblasts. These uniform SNPs of precisely controlled sizes eliminated uncertainties arising from mixed sizes, and uniquely allowed the probing of effects entirely size-dependent. Cell viability, membrane disruption, oxidative stress, and cellular uptake were studied. The extent and mechanism of SNP cytotoxicity were found to be not only size and dose dependent, but also highly cell type dependent. Furthermore, the 60 nm SNPs exhibited highly unusual behavior in comparison to particles of other sizes tested, implying interesting possibilities for controlling cellular activities using nanoparticles. Specifically, the 60 nm SNPs were preferentially endocytosed by cells and, at high doses, caused a disproportionate decrease in cell viability. The present work may help elucidate certain contradictions among existing results on nanoparticle-induced cytotoxicity. From the Clinical Editor Silica nanoparticles are being investigated in many research areas for their use in clinical applications. Nonetheless, the relationship between particle size and potential toxicity remains to be elucidated. In this article, the authors studied the biological effects of spherical SNPs with precise diameters between 20 and 200 nm on three different cell types and their results should provide more data on safety for better drug design. [ABSTRACT FROM AUTHOR]

Engineering nanoparticles (NPs) for immune modulation require a thorough understanding of their interaction(s) with cells. Gold NPs (AuNPs) were coated with polyethylene glycol (PEG), polyvinyl alcohol (PVA) or a mixture of both with either positive or negative surface charge to investigate uptake and cell response in monocyte-derived dendritic cells (MDDCs). Inductively coupled plasma optical emission spectrometry and transmission electron microscopy were used to confirm the presence of Au inside MDDCs. Cell viability, (pro-)inflammatory responses, MDDC phenotype, activation markers, antigen uptake and processing were analyzed. Cell death was only observed for PVA-NH 2 AuNPs at the highest concentration. MDDCs internalize AuNPs, however, surface modification influenced uptake. Though limited uptake was observed for PEG-COOH AuNPs, a significant tumor necrosis factor-alpha release was induced. In contrast, (PEG + PVA)-NH 2 and PVA-NH 2 AuNPs were internalized to a higher extent and caused interleukin-1beta secretion. None of the AuNPs caused changes in MDDC phenotype, activation or immunological properties. From the Clinical Editor This team of authors investigated the influence of gold nano-particles with different surface modifications on immunological properties in monocyte-derived dendritic cells. AuNPs triggered responses in these cells that has to be further investigated in terms of development of novel vaccine carriers. [ABSTRACT FROM AUTHOR]

• Oncocalixone A exhibits autofluorescence. • OncoA appears to have multicolor properties. • The encapsulation of oncoA in nanoparticles allows the evaluation of cell capture through fluorescence microscopy. • The fluorescence intensity of oncoA shows to be higher than that of rhodamine. Oncocalyxone A (oncoA) is a quinone extracted from the Cordia oncocalyx plant. This compound has pharmacological properties, such as anti-inflammatory, analgesic, and cytotoxic activities, among others. OncoA presents a similar chemical structure to doxorubicin, a drug used in cancer treatment, which possesses an intrinsic fluorescence explored in various studies, including those using doxorubicin-loaded nanoparticles. Thus, due to the chemical structural similarity, the question arose whether oncoA could also show autofluorescence. Therefore, this study proposed to characterize the absorption and emission spectral profiles of oncoA and analyze if this compound could be used as a fluorescent probe. For this, fucoidan-coated polyisobutylcyanoacrylate (PIBCA) nanoparticles containing oncoA were prepared, and an uptake study was performed using a human metastatic breast cancer cell line (MDA-MB-231 cells). OncoA presented a maximum emission wavelength in the blue region, near 430 nm, at 350 nm excitation, compatible with standard microscope optics. Fluorescence microscopy analyses showed that oncoA-loaded PIBCA nanoparticles were internalized by MDA-MB-231 cells under incubation times as shorter as 15 min. According to these findings, oncoA-encapsulated nanoparticles are promising fluorescent probes and could be useful for cellular uptake studies. [ABSTRACT FROM AUTHOR]

The present work reports the construction of a drug delivery nanovehicle via a pH-sensitive assembly strategy for improved cellular internalization and intracellular drug liberation. Through spontaneous formation of boronate linkage in physiological conditions, phenylboronic acid-modified cholesterol was able to attach onto catechol-pending methoxypoly(ethylene glycol)-block-poly(l-lysine). This comb-type polymer can self-organize into a micellar nanoconstruction that is able to effectively encapsulate poorly water-soluble agents. The blank micelles exhibited negligible in vitro cytotoxicity, yet doxorubicin (DOX)-loaded micelles could effectively induce cell death at a level comparable to free DOX. Owing to the acid-labile feature of the boronate linkage, a reduction in environmental pH from pH 7.4 to 5.0 could trigger the dissociation of the nanoconstruction, which in turn could accelerate the liberation of entrapped drugs. Importantly, the blockage of endosomal acidification in HeLa cells by NH4Cl treatment significantly decreased the nuclear uptake efficiency and cell-killing effect mediated by the DOX-loaded nanoassembly, suggesting that acid-triggered destruction of the nanoconstruction is of significant importance in enhanced drug efficacy. Moreover, confocal fluorescence microscopy and flow cytometry assay revealed the effective internalization of the nanoassemblies, and their cellular uptake exhibited a cholesterol dose-dependent profile, indicating the contribution of introduced cholesterol functionality to the transmembrane process of the nanoassembly. [ABSTRACT FROM AUTHOR]

We synthesize highly crystalline citrate-coated iron oxide superparamagnetic nanoparticles that are stable and readily dispersible in water by an extremely fast microwave-assisted route and investigate the uptake of magnetic nanoparticles by endothelial cells. Nanoparticles form large aggregates when added to complete endothelial cell medium. The size of the aggregates was controlled by adjusting the ionic strength of the medium. The internalization of nanoparticles into endothelial cells was then investigated by transmission electron microscopy, magnetometry and chemical analysis, together with cell viability assays. Interestingly, a sevenfold more efficient uptake was found for systems with larger nanoparticle aggregates, which also showed significantly higher magnetic resonance imaging effectiveness without compromising cell viability and functionality. We are thus presenting an example of a straightforward microwave synthesis of citrate-coated iron oxide nanoparticles for safe endothelial progenitor cell labeling and good magnetic resonance cell imaging with potential application for magnetic cell guidance and in vivo cell tracking. [ABSTRACT FROM AUTHOR]

Abstract: Multilayered microcapsules of chitosan and biomimetic elastin-like recombinamers (ELRs) were prepared envisaging the intracellular delivery of active agents. Two ELRs containing either a bioactive RGD sequence or a scrambled non-functional RDG were used to construct two types of functionalized polymeric microcapsules, both of spherical shape ∼4μm in diameter. Cell viability studies with human mesenchymal stem cells (hMSCs) were performed using microcapsule/cell ratios between 5:1 and 100:1. After 3 and 72h of co-incubation, no signs of cytotoxicity were found, but cells incubated with RGD-functionalized microcapsules exhibited higher viability values than RDG cells. The internalization efficacy and bioavailability of encapsulated DQ-ovalbumin were assessed by monitoring the fluorescence changes in the cargo. The data show that surface functionalization did not significantly influence internalization by hMSCs, but the bioavailability of DQ-ovalbumin degraded faster when encapsulated within RGD-functionalized microcapsules. The microcapsules developed show promise for intracellular drug delivery with increased drug efficacy. [Copyright &y& Elsevier]

Abstract: We have performed a series of in vitro tests proposed for the reliable assessment of safety associated with nanoparticles-cell interaction. A thorough analysis of toxicity of three different coating iron oxide nanoparticles on HeLa cells has been carried out including, methyl thiazol tetrazolium bromide (MTT) and Trypan blue exclusion tests, cell morphology observation by optical and Scanning Electron Microscopy (SEM), study of cytoskeletal components, analysis of cell cycle and the presence of reactive oxygen species (ROS). We have quantified magnetic nanoparticle internalization, determined possible indirect cell damages and related it to the nanoparticle coating. The results confirm a very low toxicity of the analyzed iron oxide nanoparticles into HeLa cells by multiple assays and pave the way for a more successful cancer diagnostic and treatment without secondary effects. From the Clinical Editor: In this paper, three different iron oxide nanoparticles are studied and compared from the standpoint of safety and toxicity in HeLa cells, demonstrating low toxicity for each preparation, and paving the way to potential future clinical applications. [Copyright &y& Elsevier]

Abstract: The major goal of this study was to create easy-to-use, reusable substrates capable of storing any peptides or bioactive molecules for a desired period of time until cells uptake them without the need for bioactive molecule or peptide-specific techniques. Nanopore arrays of uniform size and distribution were machined into fused silica substrates using femtosecond laser ablation and loaded with peptides by simple adsorption. The nanopore substrates were validated by examining the effect of N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) loaded nanopores on macrophage phagocytosis and intracellular production of reactive oxygen species (ROS) with and without the pro-inflammatory lipopolysaccharide (LPS). Our results demonstrated that nanopores were generated in a uniform array fashion. Ac-SDKP peptides were stably stored in nanopores and internalized by macrophages. Significant reductions in ROS production and phagocytosis in macrophages were observed over control substrates, even in combination with LPS stimulation, indicating that loading Ac-SDKP peptides in pores significantly improved the anti-inflammatory effects. From the Clinical Editor: This team of scientists intended to create easy-to-use, reusable substrates for storing peptides or bioactive molecules for a desired period of time before cellular uptake occurs, and without the need for bioactive molecule or peptide-specific techniques. They demonstrate the successful generation of nanopores in a uniform array that stably stores Ac-SDKP peptides in the nanopores. When peptides were internalized by macrophages, significant reductions in ROS production and phagocytosis were observed, indicating improved anti-inflammatory effects. [Copyright &y& Elsevier]