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Novel co-operative immuno-photodynamic therapy nanoparticles, targeting tumor-associated macrophages, modulating the tumor microenvironment, and preventing tumor metastasis by skewing TAMs to M1-like cells, have been developed.

Injectable dermal fillers, which are used for various plastic surgery purposes, are experiencing explosive growth in the market due to increasing interest in appearance management. Hyaluronic acid (HA) hydrogels have been considered an ideal material for fillers due to their high-water retention, biodegradability, and biocompatibility. However, their application is limited by shortcomings in durability and persistence caused by rapid enzymatic degradation. Therefore, in this study, we introduce acetylated hyaluronic acid-divinyl sulfone (AcHA-DVS) hydrogels for novel approach to improving the physical properties and gel retention time of HA. The AcHA-DVS hydrogels showed significant advantages in terms of longevity and performance as dermal fillers compared to HA-DVS hydrogels. These results suggest that our new AcHA-DVS hydrogel is a promising biomaterial for use as an injectable filler or scaffold of tissue engineering.

In an immunosuppressive tumor microenvironment, tumor-associated macrophages (TAMs) are the most abundant cells displaying pro-tumorigenic M2-like phenotypes, encouraging tumor growth and influencing the development of resistance against conventional therapies. TAMs are highly malleable. They can be repolarized into tumoricidal M1-like cells. In this study, we report the synthesis of novel co-operative immuno-photodynamic nanoparticles involving TAM self-targeting acrylic acid grafted mannan (a polysaccharide) conjugated with the chlorin e6 (Ce6) photosensitizer and then loaded with resiquimod (R848), a toll-like receptor (TLR7/8) agonist. The mannan conjugated Ce6 loaded with R848 (MCR) as bioconjugate nanoparticles demonstrated selective targeting of anti-inflammatory M2-like cells. Using photodynamic therapy they were repolarized to pro-inflammatory M1-like cells with combined effects of reactive oxygen species (ROS)-triggered intracellular signaling and a small-molecule immunostimulant. The MCR also demonstrated a TAM-directed adaptive immune response, inhibited tumor growth, and prevented metastasis. Our results indicate that these MCR nanoparticles can effectively target TAMs and modulate them for cancer immunotherapy.

Three-dimensional (3D) culture systems that provide a more physiologically similar environment than conventional two-dimensional (2D) cultures have been extensively developed. Previously we have provided a facile method for the formation of 3D spheroids using non-adhesive N-hexanoyl glycol chitosan (HGC) hydrogel-coated dishes, but with limitations such as low gel stability and weak mechanical properties. In this study, chemically crosslinked hydrogels were prepared by photocrosslinking of methacrylated HGCs (M-HGCs), and their spheroid-forming abilities were evaluated for long-term 3D cell cultures. The M-HGC hydrogels demonstrated not only enhanced gel stability, but also good spheroid-forming abilities. Furthermore, the M-HGC-coated dishes were effective in generating spheroids of larger size and higher cell density depending on the crosslinking density of the M-HGCs. These results indicate that our hydrogel-coated dish system could be widely applied as an effective technique to produce cell spheroids with customized sizes and densities that are essential for tissue engineering and drug screening.

Dopamine-modified hyaluronic acid (DA-HA) has been initially developed as an efficient coating and adhesion material for industrial uses. However, the biological activity and safety of DA-HA in the brain have not been explored yet. Here, we report a series of evidence that DA-HA exhibits similar functionality as dopamine (DA), but with much lower toxicity arising from autoxidation. DA-HA shows very little autoxidation even after 48-hour incubation. This is profoundly different from DA and its derivatives including L-DOPA, which all induce severe neuronal death after pre-autoxidation, indicating that autoxidation is the cause of neuronal death. Furthermore, in vivo injection of DA-HA induces significantly lower toxicity compared to 6-OHDA, a well-known oxidized and toxic form of DA, and alleviates the apomorphine-induced rotational behavior in the 6-OHDA animal model of Parkinson’s disease. Our study proposes that DA-HA with DA-like functionalities and minimal toxicity can be an effective therapeutic substitute for L-DOPA in Parkinson’s disease.

Tumor metastasis is associated with high mortality in breast cancer patients. Although photothermal therapy (PTT) has arisen as a promising anticancer treatment approach, PTT-based monotherapies still fail to eradicate advanced cancers due to the immunosuppressive microenvironment. Herein, we synthesized drug-dye-lipid-like micelles composed of thermoresponsive poloxamer conjugated with linoleic acid (PCLA) loaded with a chemotherapeutic drug doxorubicin (DOX) and a near-infrared dye IR-780 (PCLA-ID) to enhance antitumor immunity against progressive metastatic breast cancers. Intravenous administration of sub-100 nm sized PCLA-ID in breast tumor-bearing mice followed by local laser irradiation eliminated not only primary tumors, but also untreated distant tumors (abscopal effect). The combinatorial treatment of apoptosis-inducing PCLA-ID, which contained DOX at a subtherapeutic dose, and PTT augmented the maturation of tumor-draining lymph nodes, the upregulation of cytotoxic T lymphocytes, and the suppression of regulatory T cells in untreated secondary tumors. These events prevented lung metastasis in tumor-bearing mice after re-challenging with a second injection of breast cancer cells. We conclude that PCLA-ID nanoparticles can enhance immunogenic cell death, representing a promising strategy for triggering immune responses against advanced metastatic breast cancers.

Laser-induced graphene (LIG) typically exhibits a mesostructure with a small specific surface area, which is detrimental to the electrochemical performance of micro-supercapacitors (MSCs). Herein, ...

Bioactivatable polymer nanoparticles (NPs) have attracted considerable attention as a prospective cancer therapy. Herein, we describe bioactivatable reactive oxygen species (ROS)-sensitive prodrug NPs designed to elicit spatiotemporally controlled, phototriggered chemo-photodynamic therapy. First, an effective anticancer agent, doxorubicin (DOX), was conjugated to poly(ethylene glycol) (PEG) via an ROS-responsive degradable thioketal (TK) linker. The resulting amphiphilic PEG-DOX conjugate (PEG-TK-DOX) self-assembled into a bioactivatable ROS-responsive NP system could efficiently encapsulate a hydrophobic photodynamic therapy (PDT) agent, pheophorbide A (PhA), with good colloidal stability and unimodal size distribution. Second, after the selective retention of NPs in the tumor, the site-specific release of DOX and PhA was spatiotemporally controlled, initially by endogenous ROS and subsequently by exogenous ROS produced during PDT. The locoregional treatment not only photoactivates PhA molecules to generate cytotoxic ROS but also triggers an ROS cascade, which accelerates the release of DOX and PhA via the ROS-mediated structural destruction of NPs, resulting in an enhanced anticancer therapeutic effect. This prodrug-NP system may function as an effective nanomedicine platform, working synergistically to maximize the efficacy of the combination of chemotherapy and photodynamic therapy with a remote-controlled release mechanism. STATEMENT OF SIGNIFICANCE: Photodynamic therapy (PDT) is a noninvasive therapy involving local ROS generation through the activation of photosensitizer (PS) molecules induced via external irradiation with near-infrared (NIR) light. Combinational therapies with PDT could synergistically enhance the therapeutic efficacy and overcome the limitations of monotherapy. In this study, we describe bioactivatable reactive oxygen species (ROS)-sensitive prodrug nanoparticles designed to elicit spatiotemporally controlled, photo triggered chemo-photodynamic therapy. Upon accumulation in tumor by enhanced permeation and retention (EPR) effect, the nanoparticles exhibited target-specific release of chemo-drug and photosensitizer in a spatiotemporally controlled cascade manner by endogenous ROS in the initial stage and the excessive production of exogenous ROS during PDT, leading to a further ROS cascade that accelerates the release of therapeutic cargo.

Cell culture technology has evolved into three-dimensional (3D) artificial tissue models for better reproduction of human native tissues. However, there are some unresolved limitations that arise due to the adhesive properties of cells. In this study, we developed a hexanoyl glycol chitosan (HGC) as a non-cell adhesive polymer for scaffold-based and -free 3D culture. The uniform cell distribution in a porous scaffold was well maintained during the long culutre period on the HGC-coated substrate by preventing ectopic adhesion and migration of cells on the substrate. In addition, when culturing many spheroids in one dish, supplementation of the culture medium with HGC prevented the aggregation of spheroids and maintained the shape and size of spheroids for a long culture duration. Collectively, the use of HGC in 3D culture systems is expected to contribute greatly to creating excellent regenerative therapeutics and screening models of bioproducts.

We prepared a new injectable thermogel to enhance the efficiency of inner ear delivery of dexamethasone (DEX). Hexanoyl glycol chitosan (HGC) was synthesized and evaluated as an amphiphilic thermogel (T

Due to increasing safety and intracellular delivery concerns about hydrophilic polymers in amphiphilic polymer-based nanoparticles (NPs), this study investigates small hydrophilic molecule-stabilized NPs for effective intracellular delivery with multiorganelle targetability and dual responsiveness to acidic pH/glutathione (GSH). In the construction of small hydrophilic molecule-stabilized NP (MSPCL-NP), the A-B-A-type amphiphilic polymer (MSPCL-P) is composed of two short hydrophilic carboxylate-capped disulfide derivatives (A) that replace hydrophilic polymers and assist in providing colloidal stability and preventing antibody (e.g., at least anti-PEG antibody)-mediated specific interactions and complement activation in the plasma and a hydrophobic multiple disulfide-containing poly(ε-caprolactone) block (B) that carries hydrophobic drugs. The carboxylates on the surface of MSPCL-NP target the acidic extratumoral/endolysosomal milieu by sensing and buffering acidic pH values, and the hydrophobic carboxylic acids improve adsorptive endocytosis and effective endosomal escape. Multiple disulfide linkages selectively target cytosolic GSH, resulting in rapid drug release from the destroyed MSPCL-NP via the cleavage of disulfide bonds in MSPCL-P. Doxorubicin (DOX)-loaded NP (DOX@MSPCL-NP) exerts strong effects on killing cells in vitro and inhibits tumor growth in HCT116 xenograft tumor-bearing mice. In conclusion, the multifunctionality and multispatial targetability of MSPCL-NP might effectively overcome various sequential drug delivery hurdles, ranging from blood circulation to drug release. Furthermore, the introduction of small hydrophilic molecules represents a potential strategy to make self-assembled NPs without the use of hydrophilic polymers.

Thermogels have been extensively utilized as one of representative in situ forming hydrogel systems for biomedical applications. However, most thermogels often suffer from a weak mechanical strength and low physical stability. To overcome these intrinsic weaknesses of conventional thermogels, we developed a new in situ crosslinkable thermogel system with enhanced and tunable physicochemical properties. Thermosensitive N-hexanoyl glycol chitosans (HGCs) were synthesized by N-hexanoylation of glycol chitosan and further modified to yield methacrylated HGCs (M-HGCs) and thiolated HGCs (SH-HGCs). A mixture of M-HGCs and SH-HGCs (M/SH-HGCs) retained not only their thermogelling properties but also their reactive functionalities for chemical crosslinking at physiological temperature. Compared to conventional thermogels, the M/SH-HGC thermogels showed enhanced mechanical properties due to physical and chemical crosslinking mechanisms. The physicochemical properties of the M/SH-HGC thermogels were characterized in terms of the sol–gel transition temperature, gelation time, mechanical strength, and biodegradability. They showed negligible toxicity in cells, and the in situ crosslinking step did not affect cell viability. These results suggest that our crosslinkable thermogel system is useful not only as a new in situ forming hydrogel but also as a biomaterial for various biomedical applications due to its thermogelling characteristics and enhanced and tunable physicochemical properties.

Mitochondrial drug delivery systems require development of highly selective mitochondria-targeting carriers. In this study, we report that mitochondria targeting sequence (MTS)-hybrid cationic oligopeptide, MTS-H3R9, shows the dual role of a mitochondria targeting vector along with anticancer effect for cancer therapy. In cytotoxicity assays, MTS-H3R9 was shown to be more effective than MTS. MTS-H3R9 showed significant cell penetration and internalization activity compared to that of MTS along with more efficient escape from lysosome to the cytosol. We showed efficient targeting of MTS-H3R9 to mitochondria in HeLa cell line. Furthermore, we exhibited anticancer agent properties that mitochondrial-accumulated MTS-H3R9 caused cell death by reactive oxygen species generation and loss of mitochondrial membrane potential. MTS-H3R9 exhibited dramatically increased anticancer activity in 3D spheroids as well as in a 2D culture model. We demonstrated that MTS-H3R9 provides dual potentials both as a vehicle for targeted delivery and as a cancer treatment agent for therapeutic applications.

BACKGROUND: Iron oxide nanoparticles (IONPs) are excellent candidates for biomedical imaging because of unique characteristics like enhanced colloidal stability and excellent in vivo biocompatibility. Over the last decade, material scientists have developed IONPs with better imaging and enhanced optical absorbance properties by tuning their sizes, shape, phases, and surface characterizations. Since IONPs could be detected with magnetic resonance imaging, various attempts have been made to combine other imaging modalities, thereby creating a high-resolution imaging platform. Composite IONPs (CIONPs) comprising IONP cores with polymeric or inorganic coatings have recently been documented as a promising modality for therapeutic applications. METHODS: In this review, we provide an overview of the recent advances in CIONPs for multimodal imaging and focus on the therapeutic applications of CIONPs. RESULT: CIONPs with phototherapeutics, IONP-based nanoparticles are used for theranostic application via imaging guided photothermal therapy. CONCLUSION: CIONP-based nanoparticles are known for theranostic application, longstanding effects of composite NPs in in vivo systems should also be studied. Once such issues are fixed, multifunctional CIONP-based applications can be extended for theranostics of diverse medical diseases in the future.

When a therapeutic molecule is administered into a biological system, it faces numerous barriers on its way to the target site. While a portion of the administered dose can overcome these barriers, localize to the targeted site, and provide a therapeutic effect, the vast majority either accumulates off-target sites or is excreted without pharmacological benefit. Current drug delivery research aims to address this problem by protecting therapeutic molecules from the biological milieu so that they can minimize off-target toxicity, while concomitantly overcoming the associated barriers to effectively reach the location of interest. In this review, we focus biomaterials and bioengineering approaches that have potential to overcome intracellular barriers. We discuss the various systems/materials developed so far to deliver drugs and genes and the major challenges that remain unmet. Finally, we provide outlook on the importance of subcellular targeting drug delivery and give an overview on potential approaches ...

The current 2D culture model systems developed for drug screening are not sufficient to reflect the characteristics of in vivo solid tumors. Therefore, more effective in vitro tumor model systems must be developed for translational studies on therapeutic drug screening and testing. Herein, we report a new ultra-low adhesion (ULA) hydrogel for generating 3D cancer cell spheroids as tumor models in vitro. N-octanoyl glycol chitosan (OGC) was synthesized and coated onto the surface of a typical cell culture dish. Cell spheroids were effectively formed on the OGC-coated surface, and phenotypes of the tumor cells were well maintained during culture. More importantly, U373-MG cells cultured on OGC-coated plates were more resistant to doxorubicin than cells cultured on typical plates. Our OGC-based ULA system may offer a convenient method for 3D cell culture to provide enhanced performance in cancer research, drug screening and toxicology.

Multistimuli-responsive nanomedicines present great potential for cancer therapy, as they can be featured as simple, selective, and smart carriers that can release their payload on-demand. In this study, we prepared a multifunctional polymeric vesicular nanocarrier (PVN) based on robust and triple stimuli-responsive micelles that could encapsulate chemotherapeutic drugs (doxorubicin (DOX)) and photothermal agents (IR780 iodide) for combined chemo-photothermal therapy. The size of the PVNs was stable and uniform (∼100 nm), and its DOX and IR780 loading were high: 26.5 and 16.4 wt %, respectively. Further in vitro investigations suggested that the DOX/IR780 coloaded PVNs presented controlled drug release kinetics upon costimulation with specific endogenous stimuli. Upon laser irradiation, DOX/IR780 coloaded PVNs exhibited prominent photothermal cytotoxicity toward murine colon cancer (CT-26) cells. Intracellular uptake assays indicated that DOX/IR780 coloaded PVNs could be readily uptaken by CT-26 cells, resulting in the release of DOX within the cytoplasm of the cells in response to laser irradiation.

Biofunctional polymers have been widely used to enhance the proliferation and functionality of stem cells. Here, we report the development of a new biofunctional polymer, octanoyl glycol chitosan (OGC), and demonstrate its effects on the cell cycle and stem cell function using tonsil-derived mesenchymal stem cells (TMSCs). OGC treatment (100 μg/mL) significantly increased the proliferation of TMSCs, which could be attributed to cyclin D1 up-regulation in the G1 phase of the cell cycle. Additionally, OGC enhanced the ability of TMSCs to differentiate into adipocytes, chondrocytes, and osteoblasts. Taken together, this new biofunctional polymer, OGC, can promote stemness and osteogenesis, as well as induce stem cell proliferation by enhancing the intracellular metabolic rate and regulating the cell cycle. Thus, in the future, OGC could be a potential therapeutic additive for improving stem cell function.

Discovering and developing ideal cell culture methods is important for cell biology, drug development, and cell therapy. Recent studies have explored and demonstrated the use of nanoscale structures and patterns that influence cell behavior, such as 3D scaffolds. In this study, we analyzed the effects of nanopatterned-surface dishes using chondrocytes as model cells. Chondrocytes grown on nanopatterned dishes exhibited rounded shapes. Interestingly, chondrocytes have a lower COL10 mRNA level when cultured using nanopatterned dishes. The nanopatterned dishes induced G0-/G1-phase cell cycle arrest and reduced the rate of proliferation. Our results suggest that nanoscale structures can directly control cellular behaviors and can be used for chondrocyte cell culture without causing chondrocytes to lose their functions. These results help to elucidate cellular responses and behaviors in native-like environments, and this information can be used to improve human health.

Tumor microenvironment (TME)-responsive nanocarrier systems that keep the photosensitizer (PS) inactive during systemic circulation and then efficiently release or activate the PS in response to unique TME conditions have attracted much attention. Herein, we report novel TME-responsive, self-quenched polysaccharide nanoparticles (NPs) with a reactive oxygen species (ROS)-sensitive cascade. The PS, pheophorbide A (PhA), was conjugated to a water-soluble glycol chitosan (GC) through an ROS-sensitive thioketal (TK) linker. The amphiphilic GC-TK-PhA conjugates could arrange themselves into NPs and remain photoinactive due to their self-quenching effects. Upon reaching the ROS-rich hypoxic core of the tumor tissue, the NPs release the PS in a photoactive form by efficient, ROS-sensitive TK bond cleavage, thus generating potent phototoxic effects. Following near-infrared irradiation, the increase in locoregional ROS levels further accelerates the release and activation of PS. These cascade reactions caused a significant reduction in the tumor volume, demonstrating good antitumor potential.

A multifunctional nanomedicine combining magnetic resonance imaging (MRI) and photodynamic therapy (PDT) functionalities is a promising integrated platform that allows for targeted drug delivery, noninvasive monitoring of therapeutic responses, and simultaneous cancer diagnosis and treatment. A hybrid nanoparticle (NP) system with a core/shell-structured magnetic iron oxide/gold (Fe3O4/Au) NP and a photosensitizer (PS)-conjugated heparin surface layer is investigated as a novel multifunctional carrier in PDT. A thiolated heparin–pheophorbide a (PhA) conjugate (H–PhA), which is a macromolecular PS, is synthesized and introduced onto the NP surface through a gold–thiol interaction. The photoactivity of the PhA moieties on the NP surface is significantly suppressed by the quenching effect of the Fe3O4/Au NP. However, their photoactivity can be restored in a glutathione (GSH)-rich intracellular environment, which allows GSH-mediated switchable photoactivity in the hybrid NP system. As a result, marked phototoxicity and strong fluorescence signals are observed in NP-treated A549 cells under light irradiation. In an animal tumor model, Fe3O4/Au/H–PhA NPs are efficacious in photodynamic cancer treatment and exhibit prolonged circulation characteristics, enhanced tumor specificity, and higher therapeutic efficacy compared with free PhA. In addition, in vitro MRI studies reveal that the NPs could potentially serve as MRI contrast agents in cancer diagnosis and may be used to monitor the photodynamic treatment response used to accurately guide light irradiation. The present findings show that the Fe3O4/Au/H–PhA NP is a promising nanomedicine platform in PDT and cancer diagnosis.

Photo/pH dual-responsive amphiphilic diblock copolymers with alkyne functionalized pendant o-nitrobenzyl ester group are synthesized using poly(ethylene glycol) as a macroinitiator. The pendant alkynes are functionalized as aldehyde groups by the azide-alkyne Huisgen cycloaddition. The anticancer drug doxorubicin (DOX) molecules are then covalently conjugated through acid-sensitive Schiff-base linkage. The resultant prodrug copolymers self-assemble into nanomicelles in aqueous solution. The prodrug nanomicelles have a well-defined morphology with an average size of 20-40 nm. The dual-stimuli are applied individually or simultaneously to study the release behavior of DOX. Under UV light irradiation, nanomicelles are disassembled due to the ONB ester photocleavage. The light-controlled DOX release behavior is demonstrated using fluorescence spectroscopy. Due to the pH-sensitive imine linkage the DOX molecules are released rapidly from the nanomicelles at the acidic pH of 5.0, whereas only minimal amount of DOX molecules is released at the pH of 7.4. The DOX release rate is tunable by applying the dual-stimuli simultaneously. In vitro studies against colon cancer cells demonstrate that the nanomicelles show the efficient cellular uptake and the intracellular DOX release, indicating that the newly designed copolymers with dual-stimuli-response have significant potential applications as a smart nanomedicine against cancer.

Thermogels that undergo temperature-dependent sol-gel transition have recently attracted attention as a promising biomaterial for injectable tissue engineering. However, conventional thermogels usually suffer from poor physical properties and low cell binding affinity, limiting their practical applications. Here, a simple approach for developing a new thermogel with enhanced physical properties and cell binding affinity is proposed. This thermogel (AcHA/HGC) was obtained by simple blending of a new class of polysaccharide-based thermogel, N-hexanoyl glycol chitosan (HGC), with a polysaccharide possessing good cell binding affinity, acetylated hyaluronic acid (AcHA). Gelation of AcHA/HGC was initially triggered by the thermosensitive response of HGC and gradually intensified by additional physical crosslinking mechanisms between HGC and AcHA, resulting in thermo-irreversible gelation. Compared to the thermos-reversible HGC hydrogel, the thermo-irreversible AcHA/HGC hydrogel exhibited enhanced physical stability, mechanical properties, cell binding affinity, and tissue compatibility. These results suggest that our thermo-irreversible hydrogel is a promising biomaterial for injectable tissue engineering.

본 연구에서는 친수성 poly(ethylene glycol)(PEG)와 소수성 항암제인 독소루비신(DOX)의 화학적 결합에 의해 합성된 PEG-DOX conjugate를 이용하여 암 진단 및 치료가 가능한 자성 나노입자를 제조하고자 하였다. 양친매성 PEG-DOX는 수용액 내에서 자기조립 특성을 보이고, 10 ㎚ 내외의 자성 나노입자(SPION)에 대해 높은 봉입능 및 봉입률을 보였다. 제조된 PEG-DOX/SPION 나노입자는 ~100 ㎚의 균일한 사이즈 분포를 가지며 phantom 실험을 통해 조영제로서의 가능성을 확인하였다. 세포독성평가에서 DOX에 비해 낮은 독성을 보였고 최대내성용량(MTD) 평가실험에서 사망 개체가 발생하지 않았다. 결과적으로, 고함량의 항암제와 SPION으로 구성된 본 나노입자 시스템은 낮은 독성, MR 조영 특성, 수동적 및 자성 표적화능 등 다양한 생기능성을 기반으로 암 진단 및 치료에 유용한 테라그노스틱 제형에 응용될 수 있을 것으로 기대한다.

The use of injectable hydrogel formulations have been suggested as a promising strategy for the treatment of degenerative disc disease to both restore the biomechanical function and reduce low back pain. In this work, a new thermo-sensitive injectable hydrogels with tunable thermo-sensitivity and enhanced stability were developed with N-hexanoylation of glycol chitosan (GC) for treatment of degenerative disc disease, and their physico-chemical and biological properties were evaluated. The sol-gel transition temperature of the hydrogels was controlled in a range of 23–56 °С, depending on the degree of hexanoylation and the polymer concentration. In vitro and in vivo tests showed no cytotoxicity and no adverse effects in a rat model. The hydrogel filling of the defective IVD site in an ex vivo porcine model maintained its stability for longer than 28 days. These results suggest that the hydrogel can be used as an alternative material for treatment of disc herniation.

The development of biologically targeted contrast agents for X-ray computed tomography (CT) imaging remains a major challenge. Here, we investigated a green chemistry-based synthesis of lymph node-targeted mannan-capped gold nanoparticles (M-GNPs) as a CT contrast agent. In this study, mannan was used as a reducing and stabilizing agent for gold nanoparticles (AuNPs). M-GNPs were readily internalized by antigen-presenting cells (APCs) through mannose receptors-mediated endocytosis. The M-GNPs, which had a spherical morphology, had an average diameter of 9.18±0.71nm and surface plasmon resonance (SPR) absorption spectra with maximal absorption at 522nm. The M-GNPs displayed a concentration-based X-ray attenuation property with a maximum Hounsfield unit (HU) value of 303.2±10.83. The local administration of M-GNPs led to significantly enhanced X-ray contrast for the imaging of popliteal lymph nodes. These findings demonstrated that M-GNPs can be used as biologically targeted contrast agents for CT imaging.

We report a biocompatible and in situ cross-linkable hydrogel derived from hyaluronic acid via a bioorthogonal reaction and confirm the clinical potential of our hydrogel through in vivo cartilage regeneration. Gelation is attributed to copper-free click reactions between an azide and dibenzyl cyclooctyne. HA-PEG4-DBCO was synthesized and cross-linked via 4-arm PEG azide. The effects of the ratio of HA-PEG4-DBCO to 4-arm PEG azide on the gelation time, microstructure, surface morphology, equilibrium swelling, and compressive modulus were examined. The potential of a hydrogel as an injectable scaffold was demonstrated by the encapsulation of chondrocytes within the hydrogel matrix in vitro and in vivo. The results demonstrated that the hydrogel supported cell survival, and the cells regenerated cartilaginous tissue. In addition, these characteristics provide potential opportunities for the use of injectable hydrogels in tissue engineering applications.

A series of poly(N-isopropylacrylamide)30-SS-block-(cyclic-poly(L-lysine)n)-block-SS-poly(N-isopropylacrylamide)30 (n = 10, 20, 30) synthetic polymer polypeptide bio-conjugates have been synthesized for enhanced chemo-photothermal therapy. A combination of reversible addition-fragmentation chain transfer polymerization, click cycloaddition reaction, and ring-opening polymerization of α-amino acid N-carboxyanhydrides is utilized in the synthesis of a tadpole-shaped block copolymer. All the copolymers are self-assembled to nanoparticles in aqueous solutions, which are stabilized using a terephthalaldehyde crosslinker with successfully encapsulating doxorubicin (DOX) and IR780 dye. The polymer nanomicelles exhibited excellent drug loading capacity and efficiency. The in vitro drug release profiles demonstrate that the maximum release of DOX is achieved in pH 5.0 at 42 °C, in the presence of a glutathione intracellular mimic environment. IR780 dye significantly induces photothermal cytotoxicity to HT29 colon cancer lines under near-infrared laser irradiation. The new two-tailed tadpole-shaped synthetic polymer polypeptide bioconjugates exhibiting potential chemo-photothermal therapeutic effect thus appear to be a promising platform for anticancer therapy.

Polymeric micelles with simultaneous bioimaging, drug delivery monitoring, and effective delivery of therapeutic agents to target sites have attracted increasing attention in cancer therapy. In this study, a new biodegradable, pH-responsive, aggregation-induced emission (AIE)-active polycarbonate brush-like polymer was developed by combining ring-opening polymerization with click reaction. The anticancer drug, doxorubicin (DOX), was covalently conjugated to the polymer backbone via acid-sensitive Schiff base linkage, resulting in the pH-sensitive controlled release of DOX. The prodrug polymer self-assembled into nanomicelles in an aqueous solution, as confirmed using dynamic light scattering and transmission electron microscopy. Fluorescence imaging results demonstrated that prodrug micelles could be traced owing to the AIE features of micelles. In vitro drug release studies showed that DOX release was faster in acidic conditions (pH 5.0), whereas only a minimal amount of DOX was released in a physiological environment (pH 7.4). In summary, these smart prodrug micelles could be promising candidates for simultaneous intracellular imaging and cancer therapy.

Various nanopatterning techniques have been developed to improve cell proliferation and differentiation efficiency. As we previously reported, nanopillars and pores are able to sustain human pluripotent stem cells and differentiate pancreatic cells. From this, the nanoscale patterns would be effective environment for the co-culturing of epithelial and mesenchymal cell types. Interestingly, the nanopatterning selectively reduced the proliferative rate of mesenchymal cells while increasing the expression of adhesion protein in epithelial type cells. Additionally, co-cultured cells on the nanopatterning were not negatively affected in terms of cell function metabolic ability or cell survival. This is in contrast to conventional co-culturing methods such as ultraviolet or chemical treatments. The nanopatterning appears to be an effective environment for mesenchymal co-cultures with typically low proliferative rates cells such as astrocytes, neurons, melanocytes, and fibroblasts without using potentially damaging treatments.

Nanorobots are safe and exhibit powerful functionalities, including delivery, therapy, and diagnosis. Therefore, they are in high demand for the development of new cancer therapies. Although many studies have contributed to the progressive development of the nanorobot system for anticancer drug delivery, these systems still face some critical limitations, such as potentially toxic materials in the nanorobots, unreasonable sizes for passive targeting, and the lack of several essential functions of the nanorobot for anticancer drug delivery including sensing, active targeting, controlling drug release, and sufficient drug loading capacity. Here, we developed a multifunctional nanorobot system capable of precise magnetic control, sufficient drug loading for chemotherapy, light-triggered controlled drug release, light absorption for photothermal therapy, enhanced magnetic resonance imaging, and tumor sensing. The developed nanorobot system exhibits an in vitro synergetic antitumor effect of photothermal therapy and chemotherapy and outstanding tumor-targeting efficiency in both in vitro and in vivo environments. The results of this study encourage further explorations of an efficient active drug delivery system for cancer treatment and the development of nanorobot systems for other biomedical applications.

Chitosan-catechol, inspired from mussel-adhesive-proteins, is characterized by the formation of an adhesive membrane complex through instant bonding with serum proteins not found in chitosan. Using this intrinsic property, chitosan-catechol is widely applied for hemostatic needles, general hemostatic materials, nanoparticle composites, and 3D printing. Despite its versatility, the practical use of chitosan-catechol in the clinic is limited due to its undesired immune responses. Herein, a catechol-conjugated glycol chitosan is proposed as an alternative hemostatic hydrogel with negligible immune responses enabling the replacement of chitosan-catechol. Comparative cellular toxicity and in vivo skin irritation between chitosan-catechol and glycol chitosan-catechol are evaluated. Their immune responses are also assessed using histological analysis after subcutaneous implantation into mice. The results show that glycol chitosan-catechol significantly attenuates the immune response compared with chitosan-catechol; this finding is likely due to the antibiofouling effect of ethylene glycol groups and the reduced adhesion of immune cells. Finally, the tissue adhesion and hemostatic ability of glycol chitosan-catechol hydrogels reveal that these ethylene glycol groups do not dramatically modify the adhesiveness and hemostatic ability compared with nonglycol chitosan-catechol. This study suggests that glycol chitosan-catechol can be a promising alternative to chitosan-catechol in various biomedical fields such as hemostatic agents.

In the present study, a novel synthetic tissue adhesive material capable of sealing wounds without the use of any crosslinking agent was developed by conjugating thermosensitive hexanoyl glycol chitosan (HGC) with gallic acid (GA). The degree of N-gallylation was manipulated to prepare GA-HGCs with different GA contents. GA-HGCs demonstrated thermosensitive sol-gel transition behavior and formed irreversible hydrogels upon natural oxidation of the pyrogallol moieties in GA, possibly leading to GA-HGC crosslinks through intra/intermolecular hydrogen bonding and chemical bonds. The GA-HGC hydrogels exhibited self-healing properties, high compressive strength, strong tissue adhesive strength and biodegradability that were adjustable according to the GA content. GA-HGCs also presented excellent biocompatibility and wound healing effects. The results of in vivo wound healing efficacy studies on GA-HGC hydrogels indicated that they significantly promote wound closure and tissue regeneration by upregulating growth factors and recruiting fibroblasts compared to the untreated control group.

The process of evaluating the efficacy and toxicity of drugs is important in the production of new drugs to treat diseases. Testing in humans is the most accurate method, but there are technical and ethical limitations. To overcome these limitations, various models have been developed in which responses to various external stimuli can be observed to help guide future trials. In particular, three-dimensional (3D) cell culture has a great advantage in simulating the physical and biological functions of tissues in the human body. This article reviews the biomaterials currently used to improve cellular functions in 3D culture and the contributions of 3D culture to cancer research, stem cell culture and drug and toxicity screening.

Herein, we developed a facile one-pot approach to prepare amphiphilic aggregation-induced emission (AIE)-active hyperbranched fluorescent nanoparticles with a core–shell structure. This was conducted via the addition reaction between tetraphenylethylene (TPE)-OH, isophorone diisocyanate, and hyperbranched polyglycidol (HPG) using a one-pot method. The resultant AIE-active hyperbranched polymer structure was characterized by 1H nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The amphiphilic AIE-active polymer was prone to self-assemble in an aqueous solution to form core–shell type nanoparticles with a TPE core and hydroxyl groups on the core surface. The self-assembly of nanoparticles in the aqueous solution was characterized using dynamic light scattering, ultraviolet–visible spectroscopy, fluorescence spectroscopy, and transmission electron microscopy. Aggregation behavior of TPE-HPG polymer in water and diethyl ether was studied by dissipative particle dynamics simulation. Furthermore, these TPE-HPG nanoparticles exhibited a strong blue luminescence in the aqueous solution due to the aggregation of the AIE feature of TPE. These polymeric nanoparticles showed high water solubility, good photostability, and biological imaging properties. The cell viability assay and confocal microscopy imaging results suggested that the TPE-HPG fluorescent polymeric organic nanoparticles (FPNs) have low cytotoxicity and excellent biocompatibility. Thus, TPE-HPG FPNs are excellent candidates for biomedical applications.

The major limitations of typical thermogelling polymers for practical applications are low gel stability and weak mechanical properties under physiological conditions. In this study, we have synthesized a new polysaccharide-based thermogelling polymer that can be photo-crosslinked by UV irradiation to form a mechanically resilient and elastic hydrogel. Methacrylated hexanoyl glycol chitosan (M-HGC), was synthesized by a series of chemical modifications, N-hexanoylation and N-methacrylation, of glycol chitosan (GC). Various M-HGC polymers with different methacryl group contents were synthesized and their thermogelling and photo-crosslinkable properties were evaluated. The M-HGCs demonstrated a thermo-reversible sol-gel transition behavior in aqueous solutions. The thermally-induced hydrogels could be chemically crosslinked by UV-triggered photo-crosslinking. From the cytotoxicity studies using MTT and the live/dead assay, the M-HGC hydrogels showed non-cytotoxicity. These photo-crosslinkable thermogelling M-HGC polymers may hold great promises for various biomedical applications, such as an injectable delivery system and 3D cell culture.