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Glutathione (GSH) consumption-enhanced cancer therapies represent important potential cancer treatment strategies. Herein, we developed a new multifunctional diselenide-crosslinked hydrogel with glutathione peroxidase (GPx)-like catalytic activity for GSH depletion-enhanced glucose oxidase (GOx)-mediated tumor starvation and hypoxia-activated chemotherapy. By increasing acid and H 2 O 2 during GOx-induced tumor starvation, the degradation of the multiresponsive scaffold could be promoted, which led to accelerated release of the loaded drugs. Meanwhile, the overproduced H 2 O 2 led to accelerated intracellular GSH consumption under the cascade catalysis of small molecular selenides released from the degraded hydrogel, further enhancing the curative effect of in situ H 2 O 2 and subsequent multimodal cancer treatment. Following the GOx-induced amplification of hypoxia, tirapazamine (TPZ) was transformed into the highly toxic benzotriazinyl radical (BTZ·), exhibiting enhanced antitumor activity. This GSH depletion-augmented cancer treatment strategy effectively boosted GOx-mediated tumor starvation and activated the hypoxia drug, leading to significantly enhanced local anticancer efficacy. There has been a growing interest in depleting intracellular GSH as a potential strategy for improving ROS-based cancer therapy. Herein, a bioresponsive diselenide-functionalized dextran-based hydrogel with GPx-like catalytic activity was developed for GSH consumption-enhanced local starvation- and hypoxia-activated melanoma therapy. Results showed that the overproduced H 2 O 2 led to accelerated intracellular GSH consumption under the cascade catalysis of small molecular selenides released from the degraded hydrogel, further enhancing the curative effect of in situ H 2 O 2 and subsequent multimodal cancer treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Addressing the challenge of poor wound healing in chronic wounds remains complex, as the underlying physiological mechanisms are still not fully understood. Traditional wound dressings often fail to meet the specific needs of the chronic wound healing process. Recently, considerable interest has shifted toward employing biomacromolecule-based smart wound dressings to facilitate wound healing. These stimuli-responsive dressings have undergone substantial development to manage local drug delivery, demonstrating promising therapeutic effects in treating chronic wound defects. They have displayed improved drug release profiles both in vitro and in vivo. Recently, there have been advancements in the development of innovative dual and multi-stimuli responsive dressings that react to combinations of signals including pH-temperature, pH-enzyme, pH-ROS, pH-glucose, pH-NIR, and multiple stimuli. This paper offers an in-depth review of recent progress in responsive wound dressings based on biomacromolecules, with a specific focus on their design, drug release capabilities, and therapeutic advantages. [ABSTRACT FROM AUTHOR]

Bilirubin (BR) is among the most potent endogenous antioxidants that originates from the heme catabolic pathway. Despite being considered as a dangerous and cytotoxic waste product at high concentrations, BR has potent antioxidant effects leading to the reduction of oxidative stress and inflammation, which play an important role in the development and progression of cancer. The purpose of this study is to introduce PEGylated BR nanoparticles (NPs), themselves or in combination with other anti-cancer agents. BR is effective when loaded into various nanoparticles and used in cancer therapy. Interestingly, BRNPs can be manipulated to create stimuli-responsive carriers providing a sustained and controlled, as well as on-demand, release of drug in response to internal or external factors such as reactive oxygen species, glutathione, light, enzymes, and acidic pH. This review suggests that BRNPs have the potential as tumor microenvironment-responsive delivery systems for effective targeting of various types of cancers. [Display omitted] [ABSTRACT FROM AUTHOR]

Spinal cord injury (SCI) is a debilitating condition that can result in significant functional impairment and loss of quality of life. There is a growing interest in developing new therapies for SCI, and hydrogel-based multimodal therapeutic strategies have emerged as a promising approach. They offer several advantages for SCI repair, including biocompatibility, tunable mechanical properties, low immunogenicity, and the ability to deliver therapeutic agents. This article provides an overview of the recent advances in hydrogel-based therapy strategies for SCI repair, particularly within the past three years. We summarize the SCI hydrogels with varied characteristics such as phase-change hydrogels, self-healing hydrogel, oriented fibers hydrogel, and self-assembled microspheres hydrogel, as well as different functional hydrogels such as conductive hydrogels, stimuli-responsive hydrogels, adhesive hydrogel, antioxidant hydrogel, sustained-release hydrogel, etc. The composition, preparation, and therapeutic effect of these hydrogels are briefly discussed and comprehensively evaluated. In the end, the future development of hydrogels in SCI repair is prospected to inspire more researchers to invest in this promising field. Various types of hydrogels, including phase-change hydrogels, self-healing hydrogel, oriented fibers hydrogel, and self-assembled microspheres hydrogel, as well as different functional hydrogels such as conductive hydrogels, stimuli-responsive hydrogels, are employed as biological scaffolds, combined with stem cells, exosomes, and neurotrophic factors, in the treatment of SCI. [Display omitted] [ABSTRACT FROM AUTHOR]

Intelligent nanomedicines integrated with stimuli-responsive components enable on-demand customizable treatment options which would improve therapeutic outcome and reduce systemic toxicity. In this work, we explore the synergistic therapeutic potential of photodynamic therapy and immunometabolic modulation to achieve tumour regression and to trigger an adaptive immunity to prevent tumour recurrence. The therapeutic potential of the fabricated Bioengineered Immunomodulatory Organelle targeted Nanozymes (BIONs) was tested on 3D printed mini-brains which could effectively recapitulate the biologically relevant interactions between glioblastoma cells and macrophages. In the presence of glioblastoma organotypic brain slices, activated BIONs upregulated the cell surface expression of CD86, a costimulatory molecule and CD83, maturation marker, on monocyte derived dendritic cells, suggesting its ability to elicit a strong immune response. Furthermore, the antigen pulsed dendritic cells by chemotaxis and transendothelial migration readily relocate into the draining lymph node where they present the antigenic cargo to enable the proliferation of T lymphocytes. The stealth and tunable catalytic activity of BIONs prevent ROS mediated diseases such as acute kidney injury by providing environment dependent protection without compromising on its promising anti-cancer activity. [Display omitted] [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) play a crucial role in the design of novel materials. The ionic nature of ILs provides numerous advantages in drug delivery, acting as a green solvent or active ingredient to enhance the solubility, permeability, and binding efficiency of drugs. They could also function as a structuring agent in the development of nano/micro particles for drug delivery, including micelles, vesicles, gels, emulsion, and more. This review summarize the ILs and IL-based gel structures with their advanced drug delivery applications. The first part of review focuses on the role of ILs in drug formulation and the applications of ILs in drug delivery. The second part of review offers a comprehensive overview of recent drug delivery applications of IL-based gel. It aims to offer new perspectives and attract more attention to open up new avenues in the biomedical applications of ILs and IL-based gels. [Display omitted] • Discussion on the classification and properties of ionic liquids, along with their key roles in drug formulation. • Identification of the properties and applications of ionic liquids and ionogels in various delivery methods. • Exploration of the classification, preparation, processing methods, and biomedical characteristics of ionogel. • Highlighting the challenges associated with ionic liquids and ionogels in drug delivery. [ABSTRACT FROM AUTHOR]

α-cyanostilbene derivatives, known as AIE molecules, have the potential to serve as optical recorders and vapor sensor by altering the molecular aggregation and / or stacking models. Despite the significant scientific and technological importance of the correlation between molecular stacking modes and modulated optical properties, relevant research remains scarce. Herein, two thermodynamically stable crystalline phase (BCr and GCr) were found for a biphenyl-based cyanostilbenic compound, DSB-SQ , condensed from its solution. Uniquely, the BCr demonstrated reversible mechanochromism and irreversible thermalchromism, whereas GCr remained unaffected by exposure to light, heat, grinding, etc. The discoloration process was correlated with the variation of local dipole coupling modes during the phase transition, leading to a significant change in π-π overlap and delocalization of excited states. Finally, the BCr was doped with polyvinyl alcohol (PVA) to prepare a composite membrane with dynamic information storage and encryption function. [Display omitted] [ABSTRACT FROM AUTHOR]

Lung cancer is one of the major causes of cancer-related deaths worldwide. Stimuli-responsive polymers and nanoparticles, which respond to exogenous or endogenous stimuli in the tumor microenvironment, have been widely investigated for spatiotemporal chemotherapeutic drug release applications for cancer chemotherapy. We developed glutathione (GSH)-responsive polyurethane nanoparticles (GPUs) using a GSH-cleavable disulfide bond containing polyurethane that responds to elevated levels of GSH within lung cancer cells. The polyurethane nanoparticles were fabricated using a single emulsion and mixed organic solvent method. Cisplatin-loaded GSH-sensitive nanoparticles (CGPU) displayed a GSH-dose dependent release of cisplatin. In addition, a significant reduction in in vitro survival fraction of A549 lung cancer cells was observed compared to free cisplatin of equivalent concentration (survival fraction of ~0.5 and ~0.7, respectively). The in vivo biodistribution studies showed localization of fluorescently labeled GPUs (~7% of total injected dose per gram tissue) in the lung tumor regions after mouse-tail IV injections in xenograft A549 lung tumor models. The animals exposed to CGPUs also exhibited the inhibition of lung tumor growth compared to animals administered with saline (tumor growth rate of 1.5 vs. 13 in saline) and free cisplatin (tumor growth rate of 5.9) in mouse xenograft A549 lung tumor models within 14 days. These nanoparticles have potential to be used for on-demand drug release for an enhanced chemotherapy to effectively treat lung cancer. Unlabelled Image • Glutathione is abundantly available in lung cancer microenvironment. • Biodegradable polyurethane nanoparticles were fabricated via a single emulsion with a mixed organic solvent. • GSH-sensitive degradable polyurethane nanoparticles (GPUs) released encapsulated cisplatin in response to elevated glutathione levels. • Cisplatin loaded GPUs significantly reduced tumor growth in a subcutaneous A549 lung tumor mouse model compared to the free cisplatin. [ABSTRACT FROM AUTHOR]

[Display omitted] The advent of 3D printing technology in the 1980s enabled the fabrication of patient-specific products with precise shape, size, and complexity. A variety of 3D printing techniques, such as direct ink writing by extrusion, particle fusion printing, light-induced printing, volumetric bioprinting, and inkjet printing, have been explored recently for the purpose of developing desired 3D printed objects. Among these techniques, direct ink writing has been used extensively due to its affordability, ease of use, potential for scaling up, and faster speed. This approach saves time and resources while allowing for the flexible use of various materials. The lack of a variety of varied printing inks, however, continues to be an impediment to its widespread commercial use. Owing to their quick gelling behaviour, extrudability, and shape fidelity, injectable hydrogels have become interesting alternatives for printing inks. Hydrogel inks can be developed by either natural or synthetic polymers, or a combination of the both, to achieve the desired rheological and mechanical properties utilizing various strategies of crosslinking and incorporation of nanoparticles like nanoclay, bioactive glass, graphene oxide and silica nanoparticles. Further, various stimuli responsive hydrogel inks responding to various external stimuli (such as temperature, pH, magnetic field) can be developed to prepare engineered biostructures that can be used in healthcare sector. This review provides a spotlight on recent advancement in developing hydrogel inks and their different physicochemical aspects for developing desired engineered biostructures. Finally, we discuss the opportunities of 4D printing, current difficulties and future prospects for hydrogel inks-based 3D printing to emphasize the significant scope for future innovations. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract This study shows how highly branched poly(N -isopropyl acrylamide) (HB-PNIPAM) with a chain pendant solvatochromic dye (Nile red) could provide a fluorescence signal, as end groups bind to bacteria and chain segments become desolvated, indicating the presence of bacteria. Vancomycin was attached to chain ends of HB-PNIPAM or as pendant groups on linear polymers each containing Nile red. Location of the dye was varied between placement in the core of the branched polymer coil or the outer domains. Both calorimetric and fluorescence data showed that branched polymers responded to binding of both the peptide target (D-Ala-D-Aa) and bacteria in a different manner than analogous linear polymers; binding and response was more extensive in the branched variant. The fluorescence data showed that only segments located in the outer domains of branched polymers responded to binding of Gram-positive bacteria with little response when linear analogous polymer or branched polymer with the dye in the inner core was exposed to Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Nanocarriers based on β-Cyclodextrin modified with Maleic anhydride and NIPAM for dual, pH and temperature responsive drug release are reported. • Multiple functionalities conjugated to magnetic nanoparticle platform in two step one pot synthesis with urethane /urea linkages. • Simultaneous loading and release of Doxorubicin and Curcumin. • Endocytosis monitored by fluorescence. • Targeted cancer cell death in vitro manifested by significant tumor regression in vivo. Abstract Multifunctional nanoconjugates possessing an assortment of key functionalities such as magnetism, florescence, cell-targeting, pH and thermo-responsive features were developed for dual drug delivery. The novelty lies in careful conjugation of each of the functionality with magnetic Fe 3 O 4 nanoparticles by virtue of urethane linkages instead of silica in a simple one pot synthesis. Further β-cyclodextrin (CD) was utilized to carry hydrophobic as well as hydrophilic drug. Superlative release of DOX could be obtained under acidic pH conditions and elevated temperature, which coincides with the tumor microenvironment. Mathematical modelling studies revealed that the drug release kinetics followed diffusion mechanism for both hydrophobic drug and hydrophilic drug. A number of fluorophores onto a single nanoparticle produced a strong fluorescence signal to optically track the nanoconjugates. Enhanced internalization due to folate specificity could be observed by fluorescence imaging. Further their accumulation driven by magnet near tumor site led to magnetic hyperthermia. in vitro studies confirmed the nontoxicity and hemocompatibility of the nanoconjugates. Remarkable cell death was observed with drug-loaded nanoconjugates at very low concentrations in cancer cells. The internalization and cellular uptake of poor bioavailable anticancer agent curcumin were found to be remarkably enhanced on dosing the drug loaded nanoconjugates as compared to free curcumin. Site specific drug delivery due to folate conjugation and subsequent significant suppression in tumor growth was demonstrated by in vivo studies. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Stimuli responsive chitosan PVP hydrogel are prepared for wound healing applications. • Thermal analysis showed hydrogel as thermally more stable than individual chitosan and PVP. • Antimicrobial analysis revealed antibacterial activity against E. coli. • The hydrogels showed responsive swelling behavior against different media. • The distinctive pH behavior of hydrogels showed significant release profile (91.2%) of silver sulfadiazine in PBS. Abstract Stimuli responsive chitosan (CS) and poly (N-vinyl-2-pyrrolidone) (PVP) have attained hydrogel properties in the presence of 74% neutralized poly acrylic acid (PAA) which can be exploited for wound healing applications. The FTIR spectra confirmed the presence of all specific functional groups and the developed interactions in the hydrogels. The thermal analysis explained that the hydrogel samples are thermally more stable than individual chitosan and PVP. The antimicrobial analysis revealed that all the samples show antibacterial activity against E. coli and the biodegradation analysis is performed to confirm the hydrogels degradation. The hydrogels showed enhanced responsive swelling behavior against different media depending upon the amount of PVP. The %age swelling in water is decreased with the increase in the amount of PVP. The most considerable swelling behavior is observed against pH, as they manifested low swelling at acidic pH and high swelling at neutral pH while at pH 8, the prominent values are obtained. This distinctive behavior of hydrogels and their biocompatibility made them pertinent to drug delivery and their release profile is examined spectrophotometrically using silver sulfadiazine (antibiotic for burnt wounds) showed 91.2% of drug release for a period of 1 h in phosphate buffer saline (PBS) in a consistent and controlled manner. [ABSTRACT FROM AUTHOR]

The development and comparison of latent fingerprint (LFP) are crucial for the detection and identification of LFP. However, research on stable, clear, and no background interference's fluorescent materials for LFP recognition are scarce. In this study, lignin-derived carbon dots (CDs) with orange red emission were synthesized and combined with polyvinyl alcohol (PVA) matrix for identification of LFP and ink-free printing. The physicochemical and microstructure of the CDs and CDs/PVA nanocomposite have been precisely elucidated by TEM, FT-IR, XPS, SEM, and TGA to verify the reaction of CDs with PVA forming hydrogen bonds. The effect of CDs on the mechanical properties of PVA nanocomposite was studied. The tensile strength and elongation at break of PVA nanocomposite were increased by 113.01 % and 175.26 %, respectively. The shape memory and fluorescence properties of CDs/PVA nanocomposite were studied under different conditions such as water, acid, alkali and heat. The fluorescence intensity of CDs/PVA nanocomposites was enhanced due to the deprotonation of CDs surface under alkaline conditions. By coating CDs/PVA solution on LFP, a stable fluorescent fingerprint with clear ridge details was formed on the composite film, and it is applied to letterpress printing and gravure printing, enabling personal identification and ink-free printing. Obviously, the nanocomposite film prepared herein has multiple functions, providing potential for the design and manufacture of advanced all-round personal information identification and encryption applications in extremely harsh high temperature and strong alkaline environments. [Display omitted] • Lignin-derived tangerine carbon dots were prepared by a solvothermal method. • Lignin-derived CDs/PVA nanocomposites were formed by compositing CDs with PVA. • Transfer, collection and detection of LFPs and ink-free printing were realized. [ABSTRACT FROM AUTHOR]

The chemotherapeutic drug of doxorubicin (DOX) has witnessed widespread applications for treating various cancers. DOX-treated dying cells bear cellular modifications which allow enhanced presentation of tumor antigen and neighboring dendritic cell activation. Furthermore, DOX also facilitate the immune-mediated clearance of tumor cells. However, disadvantages such as severe off-target toxicity, and prominent hydrophobicity have resulted in unsatisfactory clinical therapeutic outcomes. The effective delivery of DOX drug molecules is still challenging despite the rapid advances in nanotechnology and biomaterials. Huge progress has been witnessed in DOX nanoprodrugs owing to their brilliant benefits such as tumor stimuli-responsive drug release capacity, high drug loading efficiency and so on. This review summarized recent progresses of DOX prodrug-based nanomedicines to provide deep insights into future development and inspire researchers to explore DOX nanoprodrugs with real clinical applications. [Display omitted] • DOX nanoprodrugs have been applied for the treatment of various kinds of cancers, such as ovarian, breast, lung and leukemia among others. • DOXnanoprodrugs possess various advantages, such as tumor stimuli-responsive drug release capacity, high drug loading, among others. • Mechanisms of stimuli-responsive DOX release have been summarized. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lanthanide-based hydrogel possessed reversible luminescent switching property. • Dual-stimuli luminescent switching enables flexible anti-counterfeiting designs. • Advanced luminescent hydrogel effectively protects data security. The development of data protection materials with low cost is still challenging in the era of big data and artificial intelligence. Herein, the luminescent hydrogel with luminescent switching property was prepared by the introduction of lanthanide complex into poly(vinyl alcohol) gelation matrix. The developed luminescent hydrogel showed good reversible luminescent switching behavior under the stimulation of HCl/NH 3 and Fe3+/EDTA2-, respectively. It enables the hydrogel to be applied as reversible data security storage material with low cost. The results showed that the input and erasure of data was reversible. Moreover, the fabricated data was invisible under daylight whereas it was visible under UV light. It is suitable for data protection. Furthermore, the combination of dual-stimuli was demonstrated to improve the security level of data effectively. The hydrogel also exhibited good stability against UV irradiation. The findings suggested that the stimuli-responsive luminescent hydrogel has potential application in data protection. [ABSTRACT FROM AUTHOR]

Abstract Orally administrable drug delivery vehicles are developed to manage incurable inflammatory bowel disease (IBD), however, their therapeutic outcomes are compromised by the side effects of systemic drug exposure. Herein, we use hyaluronic acid functionalized porous silicon nanoparticle to bridge enzyme-responsive hydrogel and pH-responsive polymer, generating a hierarchical structured (nano-in-nano-in-micro) vehicle with programmed properties to fully and sequentially overcome the multiple obstacles for efficiently delivering drugs locally to inflamed sites of intestine. After oral administration, the pH-responsive matrix protects the embedded hybrid nanoparticles containing drug loaded hydrogels against the spatially variable physiological environments of the gastrointestinal tract until they reach the inflamed sites of intestine, preventing premature drug release. The negatively charged hybrid nanoparticles selectively target the inflamed sites of intestine, and gradually release drug in response to the microenvironment of inflamed intestine. Overall, the developed hierarchical structured and programmed vehicles load, protect, transport and release drugs locally to inflamed sites of intestine, contributing to superior therapeutic outcomes. Such strategy could also inspire the development of numerous hierarchical structured vehicles by other porous nanoparticles and stimuli-responsive materials for the local delivery of various drugs to treat plenty of inflammatory gastrointestinal diseases, including IBD, gastrointestinal cancers and viral infections. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Anthracene-substituted acylhydrazone derivative ( AHP-T8 ) exhibits multi-stimuli-responsive fluorescence switching behaviors. The AHP-T8 exhibits mechanofluorochromism in that grinding and heating could change the emission colors. The transformation of crystalline features and amorphous state between the xerogel and ground states might be attributed to the mechanochromic luminescence properties. Protonation-deprotonation has a significant effect on the frontier molecular orbitals, resulting in AHP-T8 exhibiting remarkable and reversible acid/base stimulated fluorescence switching properties in both organogel and solid state. The multi-stimuli responsive fluorescence properties reveal that AHP-T8 may be a potential candidate for applications in sensing, security label and a fluorescence indicator for acids/bases. [ABSTRACT FROM AUTHOR]

A copper mesh with dendritic copper-oxide core-shell structure is prepared using an additive-free electrochemical deposition strategy for on-demand oil-water separation. Electrochemical manipulation of the oxidation state of the copper oxide shell phase results in opposite affinities towards water and oil. The copper mesh can be tuned to manifest both superhydrophobic and superoleophilic properties to enable oil-removal. Conversely, switching to superhydrophilic and underwater superoleophobic allows water-removal. These changes correspond to the application of small reduction voltages (<1.5 V) and subsequent air drying. In the oil-removal mode, heavy oil selectively passes through the mesh while water is retained; in water-removal mode, the mesh allows water to permeate but blocks light oil. The smart membrane achieved separation efficiencies higher than 98% for a series of oil-water mixtures. The separation efficiency remains high with less than 5% variation after 30 cycles of oil-water separation in both modes. The switchable wetting mechanism is demonstrated with the aid of microstructural and electrochemical analysis and based on the well-known Cassie-Baxter and Wenzel theories. The selective removal of water or oil from the oil-water mixtures is driven solely by gravity and yields high efficiency and recyclability. The potential applications for the relevant technologies include oil spills cleanup, fuel purification, and wastewater treatment. [ABSTRACT FROM AUTHOR]

While providing the ability to magnetically enhance delivery rates, ferrogels have not been able to produce the various types of regulated delivery profiles likely needed to direct complex biological processes. For example, magnetically triggered release after prolonged periods of payload retention have not been demonstrated and little has been accomplished towards remotely controlling release rate through alterations in the magnetic signal. Also, strategies do not exist for magnetically coordinating multi-drug sequences. The purpose of this study was to develop these capabilities through improved ferrogel design and investigating how alterations in the magnetic signal impact release characteristics. Results show that delivery rate can be remotely regulated using the frequency of magnetic stimulation. When using an optimized biphasic ferrogel design, stimulation at optimized frequencies enabled magnetically triggered deliveries after a delay of 5 days that were 690- to 1950-fold higher than unstimulated baseline values. Also, a sequence of two payloads was produced by allowing one payload to initially diffuse out of the ferrogel, followed by magnetically triggered release of a different payload on day 5. Finally, it was demonstrated that two payloads could be sequentially triggered for release by first stimulating at a frequency tuned to preferentially release one payload (after 24 h), followed by stimulation at a different frequency tuned to preferentially release the other payload (After 4 days). The strategies developed here may expand the utility of ferrogels in clinical scenarios where the timing and sequence of biological events can be tuned to optimize therapeutic outcome. [ABSTRACT FROM AUTHOR]

Non-communicable diseases including cancer, cardiovascular disease, diabetes, and neuropathy are chronic in nature. Treatment of these diseases with traditional delivery systems is limited due to lack of site-specificity, non-spatiotemporal release and insufficient doses. Numerous responsive delivery systems which respond to both physiological and external stimuli have been reported in the literature. However, effective strategies incorporating a multifactorial approach are required to control these complex wounds. This can be achieved by fabricating spatiotemporal release systems, multimodal systems or dual/multi-stimuli responsive delivery systems loaded with one or more bioactive components. Critically, these next generation stimuli responsive delivery systems that are at present not feasible are required to treat chronic wounds. This review provides a critical assessment of recent developments in the field of responsive delivery systems, highlighting their limitations and providing a perspective on how these challenges can be overcome. [ABSTRACT FROM AUTHOR]

Ion gels and self-healing gels prepared using ionic liquids (ILs) and deep eutectic solvents (DESs) have been largely investigated in the past years due to their remarkable applications in different research areas. Herewith we provide an overview on the ILs and DESs used for the preparation of ion gels, highlight the preparation and physicochemical characteristics of stimuli responsive gel materials based on co-polymers and biopolymers, with special emphasis on polysaccharides and discuss their applications. Overall, this review summarizes the fundamentals and advances in ion gels with switchable properties prepared using ILs or DESs, as well as their potential applications in electrochemistry, in sensing devices and as drug delivery vehicles. [ABSTRACT FROM AUTHOR]

Semiconductor Quantum dots (QD) has gained substantial interest in biological applications during the past decades. ZnO QDs do not include heavy metal ions, are favorable in some applications. However, ZnO QDs obtained via classic sol-gel route are unstable in water and are lack of functional groups that could be conjugated with bioactive molecules. In this paper, ZnO quantum dots (QDs) were synthesized using Zinc methacrylate as starting material. Zinc methacrylate, N-Isopropylacrylamide, N- tert -butyl acrylamide and (N-(3-aminopropyl) methacrylamide hydrochloride were copolymerized and refluxed within alkaline ethanol solution; ZnO@polymer QDs were generated in situ . Composition and photoluminescence of the obtained QDs were investigated. The QDs were utilized for labeling of bacteria E. coli. Results indicate that the emission wavelengths of the QDs were tuned in the scope of 440–482 nm; the photoluminescence of the QDs was stable in water for 15 days, ZnO composition in the QD is 7.25%, size of the QDs were in the range of 2.5–4 nm, and the QDs have binding ability to E. coli. [ABSTRACT FROM AUTHOR]

[Display omitted] • pH-Responsive supramolecular self-assembly of cinnamaldehyde (Cin) was constructed. • The obtained self-assembly was almost nonvolatile and had excellent surface activity. • The self-assembly with desirable stability could respond to the acidity environments. • The self-assembly exhibited good activities against different plant pathogenic fungi. • The self-assembly had environmental compatibility and biosafety to the plants. Plant essential oils have enormous potential in the management of crop disease for their easy availability, biocompatibility, biodegradability, and excellent antimicrobial activities. However, these substances usually show poor performance in practical applications due to the poor stability caused by their volatilization and oxidation. Herein, taking advantage of the biological characteristics that some plant pathogenic microorganisms can acidify microenvironment, a pH-responsive supramolecular self-assembly based on the Schiff base complex of cinnamaldehyde (Cin) and branched polyethylenimine (BPEI) was constructed through multiple covalent and noncovalent interactions. The results showed that the formation and physicochemical properties of the self-assembly were positively correlated with the molecular weight of BPEI. Combined with the stability, particle size, zeta potential, self-assembly rates, and morphological characteristics in different systems, BPEI with an average molecular weight of 10,000 (BPEI 10 k) was a preferable choice to push the formation of the self-assembly and the optimum mass ratio of Cin to BPEI 10 k was 3:4. The prepared spherical nanoparticles had low volatility, good surface activity, and high stability and could respond to acidic environments to release Cin by a Fickian diffusion or a non-Fickian behavior. The self-assembly exhibited superior activities against plant pathogenic fungi, desirable environmental compatibility, and convincing biosafety to the plants. These findings would provide guidance for achieving efficient utilization of aldehyde-containing plant essential oil and exploring a useful approach for sustainable plant disease management. [ABSTRACT FROM AUTHOR]

[Display omitted] • Simple blade coating technique to achieve large-scale self-assembly of graphene oxide (GO) flakes into anisotropic films with gradient structures and controlled patterning. • Statistical analysis method utilizing scanning electron microscopy images for the characterization of materials with macroscopic surface morphology. • Sensing/actuation behavior, responding to external stimuli such as temperature, humidity, and light. • Robust and flexible materials are suitable for application as integral building elements in the bioinspired design of sustainable smart housing and green constructs. Sustainable structural design, utilizing material to imitate natural biological systems, presents both promise and challenges. By avoiding interfacial problems encountered in composite counterparts, such designs offer self-adaptive materials for smart housing and green architecture, etc. In this study, we demonstrate the feasibility of large-scale self-assembly of graphene oxide (GO) flakes into anisotropic films through a simple blade coating technique. Through the application of blade coating to a highly concentrated nematic GO suspension, we successfully fabricate GO films with morphological gradient and patterning. Additionally, we propose a statistical analysis method utilizing scanning electron microscopy (SEM) images for the characterization of materials with macroscopic surface morphology. Furthermore, we explore the application of these GO films as low-dimensional soft actuators, revealing their outstanding stimuli-responsive performance and self-adaptation to environment. Such robust and flexible films can be used as integral building elements in the bioinspired design of sustainable smart housing facilitating remote robotization and sensing capabilities. [ABSTRACT FROM AUTHOR]

The ability to control drug release at a specific physiological target enables the possibility of an enhanced therapeutic effect with reduced off-target toxic side effects. The discipline of controlled drug release has grown to include most areas of medicine with examples in the literature of targeted drug delivery to the majority of organs within the human body. In addition, a variety of external stimuli used to meditate the drug release process have also been investigated. Nonetheless, the concurrent real time monitoring of drug release has not been widely studied. In this manuscript, we present a novel micellar drug delivery system that is not only capable of releasing its cargo when stimulated by light but also provides a real time analysis of the amount of cargo remaining. Controlled drug release from the delivery system was mediated by physicochemical changes of a spiropyran-merocyanine photochromic dyad, while drug quantification was enabled using a Förster Resonance Energy Transfer (FRET) relationship between the photochrome and a co-encapsulated BODIPY fluorophore. The percentage of drug released from the delivery system was significantly greater (24%) when exposed to light irradiation compared to an analogous control maintained in the dark (5%). Furthermore, the fluorescence read-out capability also enabled the drug-release process to be followed in living cells with a significantly reduced fluorescence emission observed for those cells incubated with the delivery system and exposed to light irradiation compared to control cells maintained in the dark. Combined, these results highlight the utility of this approach to theranostic drug delivery with the potential of light-triggered released together with a fluorescence read-out to enable quantification of the drug release process. [ABSTRACT FROM AUTHOR]

Many biomolecules, such as proteins and genes, are presently used as therapeutics. However, their delivery to target sites inside cells is challenging because of their large molecular size, difficulties to pass cellular membranes and their susceptibility for enzymatic and chemical degradation. Nanogels, three-dimensional networks of hydrophilic polymers, are attractive carrier systems for these biotherapeutics because they protect the biologicals against degradation and, importantly, facilitate cell internalization. Furthermore, the development of responsive nanogel delivery systems has resulted in particles that release their payloads due to a certain physiological trigger inside cells, such as in the cytosol or endocytic compartments. This paper reviews and discusses the use of nanogels, with special emphasis on biologically responsive systems, for intracellular delivery of biotherapeutics. [ABSTRACT FROM AUTHOR]

Polymer composites containing stimuli responsive small molecules have been explored for various applications, including patterning and data storage. Phthalocyanines (Pc) have been widely synthesized and used as dyes, catalysts, and optical limiting materials, as well as active components in modern organic electronic devices. The solubility of Pcs and miscibility with a polymer matrix require the use of covalently attached alkyl side chains that rarely serve any other purpose than solubility. Herein we report a polymer composite with a novel cobalt (II) Pc dye with alkyl chains connected through a photolabile linker. The materials are synthesized using standard reactions and characterized by FTIR, MALDI, and absorption and emission spectroscopies. Upon UV irradiation in solution or in the polymer films, the alkyl groups are cleaved rendering the Pc core insoluble and turning on fluorescence of the small molecule byproduct. This observation is in direct contrast to treatment of similar Pc molecules that lack the photoresponsive group. PMMA and PDMS films are patterned with resolution down to 250 μm using only 0.1 wt% of our tailored Pc molecule. This work presents a fundamental method for patterning in polymer films by tuning the solubility, color, and fluorescence of a Pc based system and could ultimately be used for sensing, data storage, or pigmentation. [ABSTRACT FROM AUTHOR]

Cancer is considered to be one of the leading causes of morbidity and mortality worldwide and nanotechnology was shown to have a unique potential to enhance the therapeutic performance of anti-cancer agents. A novel dual stimuli-responsive polyethylene glycol (PEG) block copolymer was synthesized for the decoration and stabilization of gold nanoparticles (NPs) to carry multiple anti-cancer drugs, doxorubicin (DOX), methotrexate (MTX) and 6-mercaptopurine (MP). DOX, MTX and MP were successfully loaded (the loading capacity of 37%, 12%, and 49%, respectively) into the NPs by ionic interaction (DOX and MTX) and disulphide-covalent bond formation (MP) in the polymeric shell of NPs. Furthermore, the triggered drugs release ability of NPs was shown through the comparison of simulated physiological and tumor tissue environments. The enhanced efficiency of the developed NPs and their targeted performance via MTX (target ligand of folate receptors) decoration were illustrated through the various cell cytotoxicity studies such as MTT assay, DAPI staining, and flow cytometry on various cancer cell lines with different levels of folate receptors. Our proposed idea in simultaneous delivery of three cytotoxic drugs with our newly designed PEGylated gold NPs may provide promising and novel prospect in cancer therapy. [ABSTRACT FROM AUTHOR]

Metal-Organic Frameworks (MOFs) have emerged as a promising biomedical material due to its unique features such as high surface area, pore volume, variable pore size, flexible functional groups, and excellent efficiency for drug loading. In this review, we explored the use of novel and smart metal organic frameworks as drug delivery vehicles to discover a safer and more controlled mode of drug release aiming to minimize their side effects. Here, we systematically discussed the background of MOFs following a thorough review on structural and physical properties of MOFs, their synthesis techniques, and the important characteristics to establish a strong foundation for future research. Furthermore, the current status on the potential applications of MOF-based stimuli-responsive drug delivery systems, including pH-, ion-, temperature-, light-, and multiple responsive systems for the delivery of anticancer drugs has also been presented. Lastly, we discuss the prospects and challenges in implementation of MOF-based materials in the drug delivery. Therefore, this review will help researchers working in the relevant fields to enhance their understanding of MOFs for encapsulation of various drugs as well as their stimuli responsive mechanism. [Display omitted] • Current status on applications of MOFs as anticancer drug delivery system reviewed. • MOFs exhibit versatile surface properties, thermal stability, and biodegradability. • Stimuli-responsive approaches enhances release of drugs at targeted tumor site. • Challenges and future directions of DDSs based on MOF are thoroughly discussed. • MOFs are promising candidate for future drug delivery applications. [ABSTRACT FROM AUTHOR]

Excessive fouling and wetting phenomenon during long term membrane distillation (MD) cause membrane degradation and lead to consistent need for membrane replacement. Hence, effective cleaning of fouled membrane is imperative to recover its performance without compromising structural integrity. In this work, poly(N-isopropylacrylamide) (PNIPAM) hydrogel was coated on the hydrophobic PTFE support via spray coating (SC) method to fabricate membrane with switchable wettability for membrane cleaning. By using bovine serum albumin (BSA) and sodium alginate (SA) as model foulants, the antifouling property of hydrogel coated membrane (HCM) was evaluated. Furthermore, chemical-less thermal cleaning on the fouled HCM membrane using water at different temperature was tested to determine its water flux recovery. The interchanging hydrophilic/hydrophobic properties of PNIPAM around its LCST facilitated the foulants removal. It was found that the PNIPAM layer could fully coat the membrane and the flux of HCM performance can be recovered by up to 59.58% and 73.66% after subjecting to fouling by bovine serum albumin (BSA) and sodium alginate (SA). Surface free energy study also showed that hydrogel incorporation could ease the removal of BSA and SA upon water cleaning and does not contribute to wetting phenomenon. [Display omitted] • Spray coating of preheated hydrogels on PTFE membrane for thermoresponsive properties. • Thermal actuation of hydrogels allows higher flux recovery of BSA/SA fouled membrane. • Fouling and cleaning tendencies evaluated via surface free energy changes. • No wetting phenomenon of HCM evaluated via temperature polarization coefficient. [ABSTRACT FROM AUTHOR]

A versatile drug delivery carrier that responds to external stimuli was synthesized via the emulsion polymerization process. This simple two-step process was carried out by using Poly (Methyl Methacrylate) as a soft template and a series of monomers, with desired properties, as coating monomers. It is noteworthy that during shell fabrication (2nd step) an inner cavity is created inside the nanocontainers that can be used as a host for small drug molecules. The thermo-, pH- and redox sensitive monomers used in the coating procedure were Dimethyl Amino Ethyl Methacrylate (DMAEMA), Acrylic Acid (AA) and N,N ′-(disulfanediylbis(ethane-2,1-diyl))bis(2-methylacrylamide) (Disulfide or DS), respectively. It has to be noted that DMAEMA is also pH- sensitive and acts synergistically with AA. The surface of the multi-stimuli nanocontainers was functionalized with magnetite nanoparticles in order to induce an alternating magnetic field (AMF) sensitivity. By using AMF in various strenghts and frequencies, the temperature of the final multi-stimuli nanocontainers (Q-NCs) can be increased in a controlled manner resulting in the Hyperthermia phenomenon. Loading and release studies were carried out using the anthracycline drug, Doxorubicin, aiming at the confirmation of the release mechanism. [ABSTRACT FROM AUTHOR]

Nuclear magnetic resonance (NMR) studies of acid-induced conformational switching ( trans / cis isomerization) of N , N -diarylamides bearing a pyridine moiety indicated that the trans / cis conformational preference of these amides is dependent on the relative π-electron densities of the two N -aromatic parts, and can be controlled by protonation or deprotonation of pyridine. [ABSTRACT FROM AUTHOR]

Bottom-up fabrication of functional supramolecular systems from discrete molecular building blocks is a flourishing endeavor in contemporary science and nanotechnology. Here we present the synthesis and reversible disassembly and reassembly of adual-stimuli responsive linear supramolecular polymer constructed by host-guest molecular recognition. The formation of the supramolecular polymer is driven by exceptional selective complexation property of azobenzene with β-cyclodextrin and 4,4´-bipyridinium with sulfonatocalix[4]arene, which ensures the polymer’s controlled and orthogonal responsiveness to light irradiation and redox process. The supramolecular polymerization was confirmed by 1 H NMR spectroscopy, dynamic light scattering (DLS) measurement, atomic force microscopy (AFM), and transmission electron microscopy (TEM), and its reversible photo and redox dual-responsive disassembly and reassembly behavior was as certained by UV–vis absorption spectra, cyclic voltammetry (CV), and TEM. This is the first example of a supramolecular polymer capable of reversible disassembly and reassembly driven by light and redox process, involving solely non-covalent orthogonal molecular recognition, which can be recognized by naked eyes. [ABSTRACT FROM AUTHOR]

Despite the impressive progress in forward osmosis (FO) membranes and pilot scale testing of FO process, lack of draw solutes that can be efficiently regenerated is still a limiting factor for more prolific commercial applications of FO technology. In the past decade, a large variety of draw solutes have been investigated. While many promising concepts were discussed, efforts are still needed to search for an ‘ideal’ draw solute which could enable the next breakthrough in FO technology. Besides giving a critical review on the development of FO draw solutes, we attempt to clarify some of the most important issues about draw solutes, to define the criterion for draw solutes, and to offer insights into challenges and opportunities concerning their future development. We intentionally avoid very detailed discussion on the issue of viability of FO, which was covered in several earlier reviews. Draw solutes are categorized into either non-responsive or responsive type according to their response toward external stimuli, such as heat and electromagnetic field. While the focus is on responsive draw solutes whose regeneration relies on their smart response to stimuli, non-responsive draw solutes are also discussed not only for a historic reason, but also for the valuable lessons learnt from these earlier systematic studies. [ABSTRACT FROM AUTHOR]

Spurred by significant progress in materials chemistry and drug delivery, charge-reversal nanocarriers are being developed to deliver anticancer formulations in spatial-, temporal- and dosage-controlled approaches. Charge-reversal nanoparticles can release their drug payload in response to specific stimuli that alter the charge on their surface. They can elude clearance from the circulation and be activated by protonation, enzymatic cleavage, or a molecular conformational change. In this review, we discuss the physiological basis for, and recent advances in the design of charge-reversal nanoparticles that are able to control drug biodistribution in response to specific stimuli, endogenous factors (changes in pH, redox gradients, or enzyme concentration) or exogenous factors (light or thermos-stimulation). [ABSTRACT FROM AUTHOR]

Stimuli responsive lipids, which enable control over the formation, transformation, and disruption of supramolecular assemblies, are of interest for biosensing, diagnostics, drug delivery, and basic transmembrane protein studies. In particular, spatiotemporal control over a supramolecular structure can be achieved using light activated compounds to induce significant supramolecular rearrangements. As such, a family of cationic lipids are described which undergo a permanent switch in charge upon exposure to 365 nm ultraviolet (UV) light to enable the capture of negatively charged nucleic acids within the self-assembled supramolecular structure of the lipids and subsequent release of these macromolecules upon exposure to UV light and disruption of the assemblies. The lipids are composed of either two different tripeptide head groups, Lysine–Glycine–Glycine (KGG) and Glycine–Glycine–Glycine (GGG) and three different hydrocarbon chain lengths (C 6 , C 10 , or C 14 ) terminated by a UV light responsive 1-(2-nitrophenyl)ethanol (NPE) protected carboxylic acid. The photolysis of the NPE protected lipid is measured as a function of time, and the resulting changes in net molecular charge are observed using zeta potential analysis for each head group and chain length combination. A proof of concept study for the capture and release of both linear DNA (calf thymus) and siRNA is presented using an ethidium bromide quenching assay where a balance between binding affinity and supramolecular stability are found to be the key to optimal nucleic acid capture and release. [ABSTRACT FROM AUTHOR]

Laser-generated-focused ultrasound (LGFU) holds promise for the high-precision ultrasound therapy owing to its tight focal spot, broad frequency band, and stable excitation with minimal ultrasound-induced heating. We here report the development of the LGFU as a stimulus for promoted drug release from microgels integrated with drug-loaded polymeric nanoparticles. The pulsed waves of ultrasound, generated by a carbon black/polydimethylsiloxane (PDMS)-photoacoustic lens, were introduced to trigger the drug release from alginate microgels encapsulated with drug-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles. We demonstrated the antibacterial capability of this drug delivery system against Escherichia coli by the disk diffusion method, and antitumor efficacy toward the HeLa cell-derived tumor spheroids in vitro . This novel LGFU-responsive drug delivery system provides a simple and remote approach to precisely control the release of therapeutics in a spatiotemporal manner and potentially suppress detrimental effects to the surrounding tissue, such as thermal ablation. [ABSTRACT FROM AUTHOR]

Here, we have designed and synthesized a novel cationic amphiphilic stimuli-responsive azobenzene-aminoglycoside (a small molecule) conjugate, Azo-AG 5 , and characterized it by UV and FTIR. Light responsive nature of Azo-AG 5 was assessed under UV–vis light. Self- assembly of Azo-AG 5 in aqueous solutions into nanostructures and their ability to act as drug carrier were also investigated. The nanostructures of Azo-AG 5 showed average hydrodynamic diameter of ∼255 nm with aminoglycoside moiety (neomycin) and 4-dimethylaminoazobenzene forming hydrophilic shell and hydrophobic core, respectively. In the hydrophobic core, eosin and aspirin were successfully encapsulated. Dynamic light scattering (DLS) measurements demonstrated that the nanoassemblies showed expansion and contraction on successive UV and visible light irradiations exhibiting reversible on–off switch for controlling the drug release behavior. Similar behavior was observed when these nanostructures were subjected to pH-change. In vitro drug release studies showed a difference in UV and visible light-mediated release pattern. It was observed that the release rate under UV irradiation was comparatively higher than that observed under visible light. Further, azoreductase-mediated cleavage of the azo moiety in Azo-AG 5 nanoassemblies resulted in the dismantling of the structures into aggregated microstructures. Azo-AG 5 nanostructures having positive surface charge (+9.74 mV) successfully interacted with pDNA and retarded its mobility on agarose gel. Stimuli responsiveness of nanostructures and their on–off switch like behavior ensure the great potential as controlled drug delivery systems and in other biomedical applications such as colon-specific delivery and gene delivery. [ABSTRACT FROM AUTHOR]

Stimuli responsive double hydrophilic diblock copolymers poly( N -isopropylacrylamide)- b -poly( N , N -dimethylaminopropylacrylamide) (PNIPAM- b -PDMPA) with constant degree of polymerization (DP) of PNIPAM (=127) and varying DP of PDMPA (=31 and 66) were synthesized by RAFT polymerization, and characterized by NMR, FTIR and GPC. In dilute aqueous solutions, the copolymers remain as unimers in equilibrium with loosely bound aggregates and form aggregates with PNIPAM core in the presence of NaCl or at temperatures above the LCST of PNIPAM. However, at higher temperatures i.e. above cloud point temperature (CPT) of PNIPAM 127 - b -PDMPA 66 , core–shell micelles are formed with PNIPAM core. The CPT of both block copolymers decrease in the presence of NaCl and in acidic pH, but increases with increase in DP of PDMPA. The copolymer showed enhanced surface activity in the presence of NaCl. The temperature dependent micellization observed from NMR is supported by turbidity and fluorescence. PDMPA is highly protonated in acidic pH; cryo-TEM and SANS confirm the formation of threadlike micelles in the presence of SDS. [ABSTRACT FROM AUTHOR]

A new series of 3,6-dimethyl-pyrazine-2,5-dicarboxylic acid derivatives were synthesized and both their gelation abilities and thermotropic properties were studied. These compounds are efficient organogelators and easily form stable gels in many organic solvents. Moreover, they are room temperature liquid crystals, which all show hexagonal columnar mesophase. Results of 1 H nuclear magnetic resonance ( 1 H NMR), Fourier transform infrared spectroscopy (FTIR) and ultra-violet-visible spectroscopy (UV) showed the driving forces of gelation are intra-hydrogen bonding, π–π stacking and van der Waals interaction. On the other hand, the intra-hydrogen bonding may be essential to the formation of mesophase. A Teas plot was constructed to estimate the gel formation of four synthesized pyrazinecarboxamides in organic solvents. [ABSTRACT FROM AUTHOR]

A well-defined, dual temperature- and pH-responsive drug carrier was synthesized through the radical copolymerization of methacrylic acid, N -isopropylacrylamide, and an N -(methacryloyl)glycylglycine 4-nitrophenyl ester. When the anticancer agent gemcitabine or antibiotic sulfamethoxazole was conjugated with a polymer and heated beyond its low critical solution temperature (40 °C), a dual temperature- and pH-induced phase transition was observed. This temperature was considered ideal for activating drug aggregation under hyperthermic and acidic conditions. The structure and properties of polymer drugs were investigated using nuclear magnetic resonance, Fourier transform infrared spectrometry, ultraviolet–visible absorption, transmission electron microscopy, and gel permeation chromatography. At a critical micelle concentration of 1 mg/mL, both polymer drugs formed micellar structures with diameters ranging from 50 nm to 150 nm, based on TEM image. These micelles exhibited higher pharmacological efficacy than the free drug alone did, and the cytotoxicity at the target site was substantially enhanced compared with that of the polymer–drug conjugate formed under normal physiological conditions. [ABSTRACT FROM AUTHOR]

We report here a simple, versatile bi-cell-based platform for preparing crosslinked polymeric hydrogel thin films. Briefly, a nanoporous membrane is used to separate two solutions: one containing crosslinking molecules and the other containing oligomers. The crosslinking molecule diffuses through the membrane and reacts with the oligomer to form a polymeric film at the surface of the nanopore membrane. In this paper, a proof-of-concept experiment is described using crosslinkers with imidoester moieties (dimethyl 3,3'-dithiobispropionimidate (DTBP) or dimethyl suberimidate (DMS)) and chitosan oligomers. Crosslinking with DTBP or DMS also conferred degradability to the chitosan film. The film formation was confirmed and its morphology examined with electron microscopy. The chitosan film degradation was quantified by monitoring the transport of gold nanoparticles through the chitosan film after a degradation treatment. The film synthesis method presented here can potentially be used to prepare functional hydrogel thin films for biosensors, coatings and drug delivery systems in an inexpensive, high-throughput manner. [ABSTRACT FROM AUTHOR]

A dual environmentally responsive polymer with a highly fouling-resistant surface has been developed using poly[(hydroxyethyl methacrylate-g-benzoic acid)-co-(dimethylaminoethyl methacrylate-g-2-chloro-3', 4'-dihydroxyacetophenone)] [poly[(HEMA-BA)-co-(DMAEMA-CCDP)], P1] as a coating material. The redox-sensitive disulfide containing amine end-capped Pluronic [(Plu-S-S-NH2), P2] was then introduced over the P1 surface via the formation of a pH-dependent benzoic imine bond, where the polyethylene glycol (PEG) acts as an antifouling agent. The successful adhesion of P1 and the deposition of P2 onto the P1-coated substrate were ascertained with X-ray photoelectron spectroscopy (XPS). In vitro cell adhesion followed by scanning electron microscopy (SEM) indicated an excellent antifouling nature of the P2 layer. Consequently, the reattachment of Hela cells was strongly observed when P2 layered on P1-coated substrates (P1-P2) was pretreated at lower pH and high redox conditions. The P1-P2 bilayer-coated substrate has exhibited a great advantage in its effective antifouling behaviors with well-tuned cell attachment and detachment. [ABSTRACT FROM AUTHOR]

The phase diagram of the pseudo-ternary aqueous 1-propanol (50:50 H2O:1-propanol by weight), ionic liquid acrylate, 1-(11-acryloyloxyundecyl)-3-methyl imidazolium tetrafluorborate (ILBF4), and methyl methacrylate (MMA) system is mapped for weight fractions of ILBF4 less than 0.75 at 25 °C and at 60 °C. The mapped region is composed of a very large single-phase microemulsion domain and an appreciable multi-phase (emulsion) domain. This emulsion domain shrinks in size with increasing temperature, in contrast to the homologous bromide system (ILBr) with an emulsion domain that is insensitive to temperature. Microemulsion polymerization of the 0.70/0.15/0.15 composition in this solvent/ILBF4/MMA system produces a solvogel that is further examined for its solvent and anion stimuli responsiveness. Aqueous-DMSO solvent exchange of the PF6- exchanged materials shows nearly reversible, but dissipative behavior on a macro-scale. Transformation of transparent gel to open cell porous material by anion exchange with PF6- is found to exhibit a (third) long time-scale behavior, wherein anion exchange is limited by ionic diffusion through condensed polymeric chains. The accompanying spinodal decomposition is also demonstrated to be driven by an amphiphilic anion, bis(2-ethylhexyl)sulfosuccinate, with interesting material effects to produce more pliable porous material than obtained by exchange with PF6-. Thermal and solvent annealing treatments show that these porous materials can be activated to lower their internal specific surface area, while retaining free volume available for stimuli-induced poration. [ABSTRACT FROM AUTHOR]

Abstract: Layer-by-layer assembled polyelectrolyte capsules with well-controlled architectures and great versatility have been the subject of great interest, due to their unique advantages and tremendous potentials of being excellent candidates in multidisciplinary fields. UV light responsive microcapsules, as one class of the stimuli responsive capsules, possess the abilities to active their functionalities by responding to the UV stimulus remotely without requirement of direct contact or interaction. Therefore, any advances in this field will be of great value for the establishment of approaches to fabricate UV responsive polyelectrolyte capsules for desired uses. This review presents current development of UV responsive capsules, with emphasis on the underlying design strategies and their potential applications as delivery vesicles. In particular, UV-stimulated capsule functionalities, such as cargo encapsulation, release and combined multifunctionalities by the multilayers, have been addressed. [Copyright &y& Elsevier]

Highlights: [•] Micropatterned photoresponsive ionogel microstructures using phosphonium ionic liquids. [•] Stimuli responsive materials actuated using light irradiation. [•] Characterisation of the swelling and shrinking behaviour of the ionogel microstructures. [•] Influence of surface-area-to-volume ratio on the swelling/shrinking kinetics. [•] [P6,6,6,14][NTf2] ionogel exhibits the greatest swelling 180% and the fastest shrinkage rate. [ABSTRACT FROM AUTHOR]

Highlights: [•] Stimuli-responsive magnetoliposomes (dMLs) were designed for low dose chemotherapy. [•] SPIO nanoparticles provided a bilayer trigger for intracellular doxorubicin release. [•] High dML uptake was observed in Huh-7 cell line in vitro. [•] dMLs exhibited low cytotoxicity unless activated by an external RF field. [•] Huh-7 treatment was due to doxorubicin release and not local hyperthermia. [Copyright &y& Elsevier]

Abstract: A series of new low molecular organogelators (LMOGs) with thermotropic mesophase were synthesized via the reaction of 3,6-dimethyl-pyrazine-2,5-dicarboxylic acid with p-alkoxyl anilines. These compounds readily formed stable gels in a variety of organic solvents and their self-assembly behavior, structure–property relationship were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), 1H nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR) and ultra-violet–visible spectroscopy (UV). The results showed a combination of intra-hydrogen bonding, π–π stacking and van der Waals interaction resulted in the aggregation of the organogelators to form three-dimension fibrous networks. The gels formed were multi-responsive to environmental stimuli, such as temperature, fluorinion, and shear stress. More importantly, all the organogelators exhibited thermotropic hexagonal column mesophase as revealed by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and variable temperature XRD studies. A control compound was synthesized and its gelling ability was also checked. [Copyright &y& Elsevier]

Highlights: [•] Synthesis of pH and hyperthermia sensitive magnetic microspheres (pH-HMMs). [•] In vitro toxicological study in HEK-293 cell line. [•] Dynamic in vivo imaging and biodistribution study. [•] Loading and release study. [Copyright &y& Elsevier]

Abstract: Stimuli-sensitive layer-by-layer (LbL) self-assembly systems have generated much interest among researchers worldwide due to the simplicity of the process by which they are produced and their numerous applications in drug delivery. LbL self-assembly systems involve simple alternative adsorption of oppositely charged polyelectrolytes on core materials and are thus considered to be promising tools for drug delivery and biosensing. Here, we discuss the latest findings from research into LbL systems, with special emphasis on drug delivery systems. This review highlights various stimuli-responsive LbL systems and their targeting and biosensory applications. For the convenience of readers, these stimuli-responsive LbL systems are classified as exogenous stimuli-responsive LbL systems and endogenous stimuli-responsive LbL systems. [Copyright &y& Elsevier]