Search

Osteoarthritis (OA) is the most prevalent chronic joint disorder and is a major cause of disability among the elderly population. The degeneration and damage of articular cartilage associated with OA can result in a diminished range of motion in joints, subsequently impacting fundamental activities such as ambulation, standing, and grasping objects. In severe cases, it may culminate in disability. Traditional pharmacological treatments are often accompanied by various side effects, while invasive surgical procedures increase the risk of infection and thrombosis. Consequently, identifying alternative new methods for OA treatment remains a formidable challenge. With advancements in responsive hydrogel drug delivery platforms, an increasing number of strategies have emerged to enhance OA treatment protocols. Injectable response hydrogel drug delivery platforms show many advantages in treating OA, including improved biocompatibility, prolonged drug release duration, elevated drug loading capacity and enhanced sensitivity. This article reviews the recent progress of injectable responsive hydrogel drug delivery platform for OA treatment over the past few years. These innovative methodologies present new strategies and directions for future OA treatment while summarizing a series of challenges faced during the clinical transformation of injectable response hydrogel drug delivery platforms. Overall, injectable responsive hydrogel drug delivery platforms show great potential in treating OA, especially regarding improving drug retention time and stimulus-responsive release at the lesion sites. These innovative methods provide new hope for future OA treatment and point the way for clinical applications. [ABSTRACT FROM AUTHOR]

Four-dimensional printing refers to a process through which a 3D printed object transforms from one structure into another through the influence of an external energy input. Self-folding structures have been extensively studied to advance 3D printing technology into 4D using stimuli-responsive polymers. Designing and applying self-folding structures requires an understanding of the material properties so that the structural designs can be tailored to the targeted applications. Poly(N-iso-propylacrylamide) (PNIPAM) was used as the thermo-responsive material in this study to 3D print hydrogel samples that can bend or fold with temperature changes. A double-layer printed structure, with PNIPAM as the self-folding layer and polyethylene glycol (PEG) as the supporting layer, provided the mechanical robustness and overall flexibility to accommodate geometric changes. The mechanical properties of the multi-material 3D printing were tested to confirm the contribution of the PEG support to the double-layer system. The desired folding of the structures, as a response to temperature changes, was obtained by adding kirigami-inspired cuts to the design. An excellent shape-shifting capability was obtained by tuning the design. The experimental observations were supported by COMSOL Multiphysics® software simulations, predicting the control over the folding of the double-layer systems. [ABSTRACT FROM AUTHOR]

In cancer therapy, it is essential to selectively release cytotoxic agents into the tumor to prevent the adverse effects associated with anticancer drugs. Thus, in this study, a stimuli-sensitive polymer–drug conjugate was synthesized for selective drug release. Doxorubicin (DOX) and docetaxel (DTX) were conjugated onto novel poly(jasmine lactone) based copolymer via a thioketal (TK) linker. In addition, a photosensitizer (chlorin e6) was attached to the polymer, which served as a reactive oxygen species generator to cleave the TK linker. The conjugate is readily self-assembled into micelles less than 100 nm in size. Micelles demonstrate a notable increase in their ability to cause cell death when exposed to near-infrared (NIR) light on MDA-MB-231 breast cancer cells. The increase in cytotoxicity is higher than that observed with the combination of free DOX and DTX. The accumulation of DOX in the nucleus after release from the micelles (laser irradiation) was also confirmed by confocal microscopy. In the absence of light, micelles did not show any toxicity while the free drugs were found toxic irrespective of the light exposure. The obtained results suggest the targeted drug delivery potential of micelles regulated by the external stimuli, i.e., NIR light. [ABSTRACT FROM AUTHOR]

Monoolein cubic phase incorporating poly(dimethylaminoethyl methacrylate-co-phenyl vinyl sulfide) (P(DMAEMA-co-PVS)) and indocyanine green (ICG, a photosensitizer) was prepared as a multiple-responsive carrier. P(DMAEMA-co-PVS), prepared by a free radical polymerization, was air/water interface-active and it exhibited lower critical solution temperature (LCST). The polymer increased in its LCST by H2O2 treatment, possibly because of the hydrolytic detachment of DMAEMA pendant, evidenced by 1H NMR and FT-IR spectroscopy. Water channels surrounded by lipid matrix, characteristic of cubic phase, was observed on TEM photos and the inclusion of the additives (e.g., P(DMAEMA-co-PVS) had little effect on the structure. The cubic phases increased their thermal stability upon the inclusion of the polymer chains and they maintained their integrity once the temperature was kept below 60 °C, supported by the polarized optical microscopy and the differential scanning calorimetry. The release of a cargo (i.e., fluorescent dextran) was suppressed at body temperature (37 °C) at the H2O2 concentration of normal tissue (e.g., 0.000002%), possibly due to an entangled network structure formed by the thermally induced inter/intramolecular hydrophobic interaction of the polymer chains. The release was markedly promoted at the H2O2 concentration of tumor tissue (e.g., 0.0034%), possibly because the thermally induced hydrophobic interaction can be weakened by the hydrolytic degradation. In addition, the release was significantly enhanced by NIR irradiation. The cubic phase would be used as a drug carrier which releases its payload at a target site in a selected manner in answering to H2O2 and NIR irradiation. [ABSTRACT FROM AUTHOR]

Hydrogels comprise of a group of crosslinked hydrophilic polymeric materials which are capable of absorbing and holding large quantities of water in their three-dimensional network structure without undergoing dissolution. More importantly, the ability of 'smart' hydrogels to respond to certain environmental changes e.g. pH, heat, light, magnetic field, biomolecules have set them apart as a unique class of materials. A combination of several such useful and unique properties have resulted in a tremendous progress toward development of advanced hydrogel-based materials, as is evident from an explosive amount of research publications available in this area over the last few decades. Owing particularly to their biocompatibility and biodegradability, hydrogels have become a material of prime importance in context to a wide range of applications starting from simple contact lenses to more complex ones e.g. in tissue repair, drug delivery, sensors, 3D bioprinting, soft robotics and agriculture. This review includes i) an overview of hydrogels and its classifications based on source, structure, crosslinking mechanism and stimuli responsiveness, ii) detailed discussion on some of the most advanced research works being carried out in the field over the last few years in context to few smart applications that have become the need of the hour, particularly in the domain of biomedical applications. [ABSTRACT FROM AUTHOR]

This work demonstrates our effort to develop stimuli responsive cellulose films for the detection of dimethyl amines, a biogenic amine, released during food decomposition. Herein, we demonstrate that thin layer deposition of polydiacetylene‐zinc oxide nanosheets (PDA‐ZnO) on cellulose (CE) paper yields a stimuli responsive strip exhibiting strong thermochromism and solvatochromism against dimethyl amine. The incorporation of Zn nanoclusters within the composite plays an essential role in achieving reversible thermochromism while strong intermolecular interactions promote adsorption of PDA‐ZnO on cellulose paper. X‐ray diffraction and infrared spectroscopy reveal that the Zn2+ ions intercalate with PDA bilayer and strongly interact with the carboxylate headgroup of PDA. Furthermore, the reversible thermochromism persist when the nanosheets are deposited on cellulose (CE) paper when assembling PDA‐ZnO−CE paper. In addition, PDA‐ZnO−CE displayed selective solvatochromism allowing the utilization of the paper in the detection of dimethyl amine as it displayed a distinct and remarkable purple to orange colour transition. In particular, the response of the PDA‐ZnO−CE paper in several other organic solvents was poor as no transitions were observed hence its selectivity towards dimethylamine. In conclusion, the incorporation of PDA‐ZnO on cellulose paper is a step forward towards designing of a stimuli responsive packaging material that can detect biogenic amines released during food decomposition thereby preventing food poisoning. [ABSTRACT FROM AUTHOR]

Nanotechnology-enabled pesticide delivery systems have been widely studied and show great prospects in modern agriculture. Nanodelivery systems not only achieve the controlled release of agrochemicals but also possess many unique characteristics. This study presents the development of a pH-responsive pesticide nanoformulation utilizing hollow mesoporous silica nanoparticles (HMSNs) as a nanocarrier. The nanocarrier was loaded with the photosensitive pesticide prochloraz (Pro) and then combined with ZnO quantum dots (ZnO QDs) through electrostatic interactions. ZnO QDs serve as both the pH-responsive gatekeeper and the enhancer of the pesticide. The results demonstrate that the prepared nanopesticide exhibits high loading efficiency (24.96%) for Pro. Compared with Pro technical, the degradation rate of Pro loaded in HMSNs@Pro@ZnO QDs was reduced by 26.4% after 24 h ultraviolet (UV) exposure, indicating clearly improved photostability. In a weak acidic environment (pH 5.0), the accumulated release of the nanopesticide after 48 h was 2.67-fold higher than that in a neutral environment. This indicates the excellent pH-responsive characteristic of the nanopesticide. The tracking experiments revealed that HMSNs can be absorbed by rice leaves and subsequently transported to other tissues, indicating their potential for effective systemic distribution and targeted delivery. Furthermore, the bioactivity assays confirmed the fungicidal efficacy of the nanopesticide against rice blast disease. Therefore, the constructed nanopesticide holds great prospect in nanoenabled agriculture, offering a novel strategy to enhance pesticide utilization. [ABSTRACT FROM AUTHOR]

Cancer therapy currently focuses on personalized targeted treatments. A promising approach uses stimuli-responsive biomaterials for site-specific drug release, such as pH- and redox-triggered polymer nanocomposites. These materials respond to the tumor microenvironment, enhance efficacy, and reduce off-target effects. Cancer cells with anomalous properties such as acidic cytosolic pH and elevated redox potential are targeted by these biomaterials. An imbalance in ions and biological thiols in the cytoplasm contributes to tumor growth. Functionalized polymer nanocomposites with large surface areas and specific targeting outperform conventional small-molecule materials. To overcome problems such as low bioavailability, uncontrolled drug release, and poor cell penetration, multifunctional nanomaterials make it easier for drugs to enter certain cellular or subcellular systems. High therapeutic efficacy is achieved through surface functionalization, site-specific targeting, and the use of stimuli-responsive components. In particular, pH and redox dual-stimuli-based polymeric nanocomposites for cancer therapeutics have scarcely been reported. This article provides recent progress in pH- and redox-responsive polymer nanocomposites for site-specific drug delivery in cancer therapy. It explores the design principles, fabrication methods, mechanisms of action, and prospects of these dual-stimuli-responsive biomaterials. [ABSTRACT FROM AUTHOR]

Copyright of Coatings & Protection / Tuceng yu Fanghu is the property of Coating & Protection Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Functional membranes based on stimuli-responsive block copolymers have attracted significant attention in the field of membrane separations, which can adjust the pore sizes and the surface properties in response to environmental stimuli. However, it was inconvenient to synthesize stimuli-responsive block copolymers due to the complexity and inefficiency of the synthesis process. In this work, pH- and thermal-responsive triblock copolymers were synthesized by the one-pot method to modify PVDF membranes. The modified membranes exhibit good hydrophilicity, and the contact angle of M2 decreased from 74° to 0° within 20 s. Surprisingly, the water flux of the blend membrane is approximately 24 times and 33 times higher than that of the pure membrane, respectively. Besides, the modified membranes also exhibit good pH and thermal response, and superior fouling-tolerant performance. Overall, these multi-responsive block copolymers synthesized by a simple one-pot method have enormous potential for controlled size separation, flux regulation, and many other fields. [ABSTRACT FROM AUTHOR]

Cancer has remained one of the leading causes of death worldwide, with a lack of effective treatment. The intrinsic shortcomings of conventional therapeutics regarding tumor specificity and non-specific toxicity prompt us to look for alternative therapeutics to mitigate these limitations. In this regard, we developed multifunctional bimetallic (FeCo) bi-MIL-88B-FC MOFs modified with folic acid--conjugated chitosan (FC) as drug delivery systems (DDS) for targeted delivery of 5-Fluorouracil (5-FU). The bi-MIL-88B nanocarriers were characterized through various techniques, including powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, thermogravimetric analysis, and Fourier transform infrared spectroscopy. Interestingly, 5-FU@bi-MIL-88B-FC showed slower release of 5-FU due to a gated effect phenomenon endowed by FC surface coating compared to un-modified 5-FU@bi-MIL-88B. The pH-responsive drug release was observed, with 58% of the loaded 5-FU released in cancer cells mimicking pH (5.2) compared to only 24.9% released under physiological pH (5.4). The in vitro cytotoxicity and cellular internalization experiments revealed the superiority of 5-FU@bi-MIL-88B-FC as a highly potent targeted DDS against folate receptor (FR) positive SW480 cancer cells. Moreover, due to the presence of Fe and Co in the structure, bi-MIL-88B exhibited peroxidase-like activity for chemodynamic therapy. Based on the results, 5-FU@bi-MIL-88B-FC could serve as promising candidate for smart DDS by sustained drug release and selective targeting. [ABSTRACT FROM AUTHOR]

Hydrogels based on dynamic covalent bonds have unique properties and are competent in many biomedical fields. However, critical issues such as biocompatibility, mechanical properties, and stimulus responsiveness are required to be solved. It is also expected to develop a simple preparation method with mild conditions. Based on these objectives, chitosan (CS), sodium alginate (SA) and 2‐formylphenylboronic acid (2‐FPBA) are used to prepare the dynamic covalent bond hydrogels within minutes neither chemical medications nor severe conditions. Benefiting from the imine borate and boronic ester bonds both formed in the hydrogels, the hydrogels are stable, injectable, and of efficient self‐healing properties. The damage‐recovery process can be repeated for more than 6 cycles. The microstructure of the hydrogels recoded by atomic force microscopy (AFM) is consistent with the mechanical properties and both of them could be affected by the concentrations of SA and 2‐FPBA. Moreover, the dynamic hydrogels are responsive to pH values and oxidative environment. When the model drug 5‐fluorouracil (5‐FU) is loaded in the dynamic hydrogels, the release profiles are sustainable and present significant differences with various stimuli. These dynamic covalent bond hydrogels have a promising prospect in tissue engineering and drug delivery. [ABSTRACT FROM AUTHOR]

Development of efficient and low cost electrocatalysts has been an important area of research in the field of materials chemistry. In this regard metal‐organic gels (MOGs) are one of the promising materials and they are being utilized for various materials applications including energy conversion and storage. Electrochemical applications of the MOGs are still in its infancy and further studies are required for exploration of structure‐property correlation that is crucial for targeted and efficient materials design. Herein we report multi stimuli responsive MOGs containing a tris‐tetrazole‐tri‐amido based organic ligand. The self‐assembly of the threefold symmetric ligand with Co(II)/Ni(II) acetates results in the MOGs with distinct morphological and structural characteristics, regardless of containing the same organic ligand. These MOGs were synthesized by direct mixing of the precursors under ambient conditions. The xerogels of these MOGs (Co‐MOG′ and Ni‐MOG′) exhibit excellent OER performance as the Co‐MOG′ and Ni‐MOG′ shows the overpotential of 312 mV and 418 mV at 10 mA/cm2 in an alkaline electrolyte. Electrocatalytic performance of the xerogels were correlated to their structural features like distinct morphology and porosity of the material that facilitates the mass transfer and maximum exposure to the electrochemical active sites. Importantly, this work demonstrates the functional application of MOGs as electrocatalysts for OER and the effect of metal ion, porosity and morphology on their overall performance. [ABSTRACT FROM AUTHOR]

Stimuli‐responsive or smart materials have recently shown a significant impact on the frontier of material science and engineering. The exponential development of synthetic host molecules (SHMs) over the last decades and their corresponding host–guest chemistry, have empowered researchers with new opportunities to design and construct tailored or guest‐specific smart materials. In this Minireview, we present the recent advancements in synthetic host based smart materials, ranging from the fabrication strategies to the state‐of‐art applications including adsorption, separation, luminescence, self‐healing and actuation. The role that the host–guest chemistry plays in these systems is highlighted throughout to give a better prospective of the available possibilities for emerging materials of future economies. [ABSTRACT FROM AUTHOR]

Stimuli‐responsive or smart materials have recently shown a significant impact on the frontier of material science and engineering. The exponential development of synthetic host molecules (SHMs) over the last decades and their corresponding host–guest chemistry, have empowered researchers with new opportunities to design and construct tailored or guest‐specific smart materials. In this Minireview, we present the recent advancements in synthetic host based smart materials, ranging from the fabrication strategies to the state‐of‐art applications including adsorption, separation, luminescence, self‐healing and actuation. The role that the host–guest chemistry plays in these systems is highlighted throughout to give a better prospective of the available possibilities for emerging materials of future economies. [ABSTRACT FROM AUTHOR]

The last decade has seen a meteoric rise in studies investigating polymeric aggregates as nanocarriers. When it comes to morphology, size, functionality, and immunostability, polymeric nanocarriers (PNCs) are unparalleled. With characteristics such as large surface area to volume ratio, amphiphilic nano‐environment, non‐toxic components, chemically modifiable composition, external surface alteration potential, uniform particle size, and stimuli‐dependent self‐assembly, PNCs have emerged as strong candidates for therapeutic applications. The article reviews the latest research on different challenges and strategies for targeted drug delivery and shall serve as guide to the researchers in designing site‐specific nanocarriers for application in future. The review systematically discusses the fundamental structural variation of the nanocarriers with emphasis on the influence of chemical alterations and the resulting effects on functionality; addresses the difficulties encountered with modes of administration; target selectivity and stimulus response. [ABSTRACT FROM AUTHOR]

Deoxyribonucleic acid (DNA) hydrogels are a unique class of programmable, biocompatible materials able to respond to complex stimuli, making them valuable in drug delivery, analyte detection, cell growth, and shape‐memory materials. However, unmodified DNA hydrogels in the literature are very soft, rarely reaching a storage modulus of 103 Pa, and they lack functionality, limiting their applications. Here, a DNA/small‐molecule motif to create stiff hydrogels from unmodified DNA, reaching 105 Pa in storage modulus is used. The motif consists of an interaction between polyadenine and cyanuric acid—which has 3‐thymine like faces—into multimicrometer supramolecular fibers. The mechanical properties of these hydrogels are readily tuned, they are self‐healing and thixotropic. They integrate a high density of small, nontoxic molecules, and are functionalized simply by varying the molecule sidechain. They respond to three independent stimuli, including a small molecule stimulus. These stimuli are used to integrate and release DNA wireframe and DNA origami nanostructures within the hydrogel. The hydrogel is applied as an injectable delivery vector, releasing an antisense oligonucleotide in cells, and increasing its gene silencing efficacy. This work provides tunable, stimuli‐responsive, exceptionally stiff all‐DNA hydrogels from simple sequences, extending these materials' capabilities. [ABSTRACT FROM AUTHOR]

For effective treatment of various diseases, pharmaceutical world require smart drug delivery systems in order to improve bioavailability, bio-degradability, site specific delivery and controlled release of drug. For this purpose, stimuli-responsive hydrogel comprised of polysaccharides chitosan and pectin, synthetic polymer polyvinylalcohol (PVA) and environment friendly coupling agent 3-aminopropyl (diethoxy)methylsilane (3-APDEMS) was fabricated. These polymers were blended and crosslinked with varying amount of crosslinker via solution casting technique. FTIR characterization elucidated the presence of chitosan, pectin and PVA functional groups as well as newly developed chemical and physical bondings. TGA showed increase in thermal stability with increase in the concentration of crosslinker. Swelling analysis depicted the successful crosslinking of polymeric chains as the swelling decreased with increase in crosslinker concentration. The change in swelling of hydrogels with change in pH of buffer media indicated the pH-dependent response of prepared stimuli responsive hydrogel. Hydrophilicity (72°) and porosity (79%) of prepared hydrogels were investigated. Furthermore, in vitro biodegradation, antibacterial and cytotoxicity analyses were also performed. The accumulative drug release was conducted in phosphate buffer saline solution and found that more than 90% of ceftriaxone was released in 180 min in controlled way that makes them ideal candidate for drug delivery and controlled release application. [ABSTRACT FROM AUTHOR]

Stimuli‐responsive polymer networks like microgels and hydrogels possess a variety of properties that need to be analyzed for their rational design and successful application in the targeted field of interest. Nanoscale characterization of gels can be achieved by highly selective and sensitive techniques including high‐resolution NMR spectroscopy, relaxometry, and diffusometry. This review is focusing on recent results using 1H and 13C 1D and 2D NMR techniques, which give chemically site‐selective information about the polymer network revealing the interplay between structure and dynamics of polymer networks at the nanoscale level. By that, NMR can allow to obtain information about i) internal structure, ii) stimuli‐induced phase transition, iii) mesh size, and iv) aggregation of microgels and hydrogels. The rational design of responsive microgels and hydrogels with application in drug delivery, cell carrier systems, catalysis, actuators, and as antibacterial agent can be made, if crucial polymer network properties can be correlated with cross‐linking density, type of cross‐link interactions, electrical charges, hydrophobic nano‐structuring, and dispersion concentration. [ABSTRACT FROM AUTHOR]

This study aimed to develop a smart cotton fabric with wetting and water vapor permeability properties stimulated by a certain temperature. N-vinyl caprolactam (VCL) based poly(2-hydroxyethyl-6-(vinyl amino)hexanoate) (PHEVAH) polymer was evaluated as a potential polymer to bear this desired properties and synthesized by free radical addition polymerization. HEVAH monomer was produced by hydrolyzing VCL with ethylene glycol in toluene to open its ring structure and obtain a new monomer with a different functional group. The produced polymer was grafted to a cotton fabric using 1,2,3,4-butanetetracarboxylic acid. The synthesis of the PHEVAH polymer with average molecular weight of 4000 g/mole was confirmed by 1 H-NMR spectroscopy. The lowest critical solution temperature (LCST) was found to be about 34 °C, which is slightly higher than its equivalents in the literature. The surface morphology of the fabrics coated by the polymer was investigated by SEM images. The temperature-sensitive hydrophilicity and wettability of the fabrics were determined by wetting time and water uptake tests, and contact angle measurements. At temperatures above the LCST of the polymer, the hydrophilic character of the fabrics turned to hydrophobic and therefore surface contact angles increased and water uptake values decreased. The vapor permeability of the fabrics treated with polymer solution at low concentration was significantly higher than that of the untreated fabric. Consequently, the fabrics were able to control water vapor permeability upon temperature stimulated hydrophilic to hydrophobic character and therefore porosity resulting from swelling or shrinkage of the polymer molecules. Besides, PHEVAH polymer formed a flexible coating on the fabric surface and did not increase the bending rigidity of the fabrics. [ABSTRACT FROM AUTHOR]

Herein, we report a stimuli-responsive hydrogel with inhibitory activity against Escherichia coli prepared by chemical crosslinking of carboxymethyl chitosan (CMCs) and hydroxyethyl cellulose (HEC). The hydrogels were prepared by esterification of chitosan (Cs) with monochloroacetic acid to produce CMCs which were then chemically crosslinked to HEC using citric acid as the crosslinking agent. To impart a stimuli responsiveness property to the hydrogels, polydiacetylene-zinc oxide (PDA-ZnO) nanosheets were synthesized in situ during the crosslinking reaction followed by photopolymerization of the resultant composite. To achieve this, ZnO was anchored on carboxylic groups in 10,12-pentacosadiynoic acid (PCDA) layers to restrict the movement of the alkyl portion of PCDA during crosslinking CMCs and HEC hydrogels. This was followed by irradiating the composite with UV radiation to photopolymerize the PCDA to PDA within the hydrogel matrix so as to impart thermal and pH responsiveness to the hydrogel. From the results obtained, the prepared hydrogel had a pH-dependent swelling capacity as it absorbed more water in acidic media as compared to basic media. The incorporation of PDA-ZnO resulted in a thermochromic composite responsive to pH evidenced by a visible colour transition from pale purple to pale pink. Upon swelling, PDA-ZnO-CMCs-HEC hydrogels had significant inhibitory activity against E. coli attributed to the slow release of the ZnO nanoparticles as compared to CMCs-HEC hydrogels. In conclusion, the developed hydrogel was found to have stimuli-responsive properties and inhibitory activity against E. coli attributed to zinc nanoparticles. [ABSTRACT FROM AUTHOR]

Timolol Maleate is used as a first-line treatment for open-angle glaucoma. It has low bioavailability and poor therapeutic effects because of the rapid precorneal removal of the conventional formulation. A study has found a selection of container closure that was safe, efficient, and stable for the formulation of multi-stimuli-responsive ocular sustained in situ hydrogels. The timolol maleate in situ gelling method was optimized and characterized in order to obtain desired quality attributes. Bulk preparations were autoclave sterilized (121 °C, 15 pressure for 20 min) and then filled into a specified container closing system. An accelerated stability analysis was carried out on optimized ocular formulation in accordance with ICH guidelines. The degradation rate for the optimized ocular formulation was found to be exceptionally low (1998 × 10−4 day−1) during stability testing. From the stability results, in situ gelling systems may assigned two years of shelf life. [ABSTRACT FROM AUTHOR]

Stimuli-responsive synthetic polypeptide-containing block copolymers have received considerable attention in recent years. Especially, unique thermo-induced sol–gel phase transitions were observed for elaborately-designed amphiphilic diblock copolypeptides and a range of poly(ethylene glycol) (PEG)-polypeptide block copolymers. The thermo-induced gelation mechanisms involve the evolution of secondary conformation, enhanced intramolecular interactions, as well as reduced hydration and increased chain entanglement of PEG blocks. The physical parameters, including polymer concentrations, sol–gel transition temperatures and storage moduli, were investigated. The polypeptide hydrogels exhibited good biocompatibility in vitro and in vivo , and displayed biodegradation periods ranging from 1 to 5 weeks. The unique thermo-induced sol–gel phase transitions offer the feasibility of minimal-invasive injection of the precursor aqueous solutions into body, followed by in situ hydrogel formation driven by physiological temperature. These advantages make polypeptide hydrogels interesting candidates for diverse biomedical applications, especially as injectable scaffolds for 3D cell culture and tissue regeneration as well as depots for local drug delivery. This review focuses on recent advances in the design and preparation of injectable, thermo-induced physically crosslinked polypeptide hydrogels. The influence of composition, secondary structure and chirality of polypeptide segments on the physical properties and biodegradation of the hydrogels are emphasized. Moreover, the studies on biomedical applications of the hydrogels are intensively discussed. Finally, the major challenges in the further development of polypeptide hydrogels for practical applications are proposed. [ABSTRACT FROM AUTHOR]

Lung cancer is one of the most common cancers, affecting more than 2.1 million people across the globe every year. A very high occurrence and mortality rate of lung cancer have prompted active research in this area with both conventional and novel forms of therapies including the use of nanomaterials based drug delivery agents. Specifically, the unique physico-chemical and biological properties of porous nanomaterials have gained significant momentum as drug delivery agents for delivering a combination of drugs or merging diagnosis with targeted therapy for cancer treatment. This review focuses on the emergence of nano-porous materials for drug delivery in lung cancer. The review analyses the currently used nanoporous materials, including inorganic, organic and hybrid porous materials for delivering drugs for various types of therapies, including chemo, radio and phototherapy. It also analyses the selected research on stimuli-responsive nanoporous materials for drug delivery in lung cancer before summarizing the various findings and projecting the future of emerging trends. This review provides a strong foundation for the current status of the research on nanoporous materials, their limitations and the potential for improving their design to overcome the unique challenges of delivering drugs for the treatment of lung cancer. [ABSTRACT FROM AUTHOR]

Electromerism is a very well‐known phenomenon in transition metal chemistry. In main group chemistry, this concept has only started getting attention recently. We report stimuli responsive low‐valent silicon compounds exhibiting electromerism. A mixed‐valent silaiminyl‐silylene 1, [LSi−Si(NDipp)L] (L=PhC(NtBu)2), was synthesized in a single step from amidinate‐chlorosilylene. Compound 1 has two interconnected Si atoms in formally +I and +III oxidation states. Upon treatment with Lewis acidic CuIX (X=mesityl, Cl, Br, I), electron redistribution occurs resulting in the formation of [{LSi(NDipp)Si(L)}−CuX], in which both silicon atoms are in the +II formal oxidation state. Removal of the copper center from [{LSi(NDipp)Si(L)}−CuX] by using a Lewis basic carbene led to reformation of the precursor [LSi−Si(NDipp)L]. Thus, the process is fully reversible. This showcases the first example of Lewis acid/base‐induced reversible electromerism in silicon chemistry. [ABSTRACT FROM AUTHOR]

Electromerism is a very well‐known phenomenon in transition metal chemistry. In main group chemistry, this concept has only started getting attention recently. We report stimuli responsive low‐valent silicon compounds exhibiting electromerism. A mixed‐valent silaiminyl‐silylene 1, [LSi−Si(NDipp)L] (L=PhC(NtBu)2), was synthesized in a single step from amidinate‐chlorosilylene. Compound 1 has two interconnected Si atoms in formally +I and +III oxidation states. Upon treatment with Lewis acidic CuIX (X=mesityl, Cl, Br, I), electron redistribution occurs resulting in the formation of [{LSi(NDipp)Si(L)}−CuX], in which both silicon atoms are in the +II formal oxidation state. Removal of the copper center from [{LSi(NDipp)Si(L)}−CuX] by using a Lewis basic carbene led to reformation of the precursor [LSi−Si(NDipp)L]. Thus, the process is fully reversible. This showcases the first example of Lewis acid/base‐induced reversible electromerism in silicon chemistry. [ABSTRACT FROM AUTHOR]

Purpose: In this study, fabrication of polymer and cotton fabric exhibiting stimuli-responsive wetting and water vapor permeability features together with antibacterial activity was aimed. Design/methodology/approach: Temperature and pH-responsive poly(N-isopropyl acrylamide-graft-chitosan) (PNIPAM-g-CS) copolymer were produced via the free radical addition polymerization method and fixed to the cotton fabric using butane tetracarboxylic acid (BTCA) cross-linker by double-bath impregnation method. The chemical structure of the graft copolymer was characterized by Fourier-transform infrared spectroscopy (FT-IR) spectroscopy and H-Nuclear magnetic resonance (1H NMR) analyses. Thermo-responsive behavior of the fabric was investigated by wetting time and water uptake tests, contact angle measurement and surface energy calculation. Additionally, antibacterial activity of the fabric treated with copolymer was studied against S. aureus bacterium. Findings: PNIPAM-g-CS graft copolymer was synthesized successfully, which had lower critical solution temperature (LCST) value of 32 °C and exhibited thermo-responsive property. The treated fabrics exhibited hydrophilic character at temperatures below the LCST and hydrophobic character at temperatures above the LCST. It was found that polymer-coated fabric could have regulated the water vapor permeability by the change in its pore size and hydrophilicity depending on the temperature. Additionally, treated fabric displayed a pH-responsive water absorption behavior and strong antibacterial activity against S.aureus bacterium. Originality/value: In the study, it has been shown that the cotton fabrics can be fabricated which have antibacterial activity and capable of pH and temperature responsive smart moisture/water management by application of copolymer. It is thought that the fabric structures developed in the study will be promising in the production of medical textile structures where antibacterial activity and thermophysiological comfort are important. [ABSTRACT FROM AUTHOR]

Cancer seriously threatens human health. Surgery, radiotherapy and chemotherapy are the three pillars of traditional cancer treatment, with targeted therapy and immunotherapy emerging over recent decades. Standard drug regimens are mostly executed via intravenous injection (IV), especially for chemotherapy agents. However, these treatments pose severe risks, including off-target toxic side effects, low drug accumulation and penetration at the tumor site, repeated administration, etc., leading to inadequate treatment and failure to meet patients' needs. Arising from these challenges, a local regional anticancer strategy has been proposed to enhance therapeutic efficacy and concomitantly reduce systemic toxicity. With the advances in biomaterials and our understanding of the tumor microenvironment, in situ stimulus-responsive hydrogels, also called smart hydrogels, have been extensively investigated for local anticancer therapy due to their injectability, compatibility and responsiveness to various stimuli (pH, enzyme, heat, light, magnetic fields, electric fields etc.). Herein, we focus on the latest progress regarding various stimuli that cause phase transition and drug release from smart hydrogels in local regional anticancer therapy. Additionally, the challenges and future trends of the reviewed in situ smart hydrogels for local drug delivery are summarized and proposed. [ABSTRACT FROM AUTHOR]

Systemic treatments for rheumatoid arthritis are associated with many side effects. This study aimed to minimize the side effects associated with the systemic administration of leflunomide (LEF) by formulating LEF-loaded emulsomes (EMLs) for intra-articular administration. Additionally, EMLs were loaded with supramagnetic nanoparticles (SPIONs) to enhance joint localization, where a magnet was placed on the joint area after intra-articular administration. Full in vitro characterization, including colloidal characteristics, entrapment efficiency, and in vitro release were conducted besides the in vivo evaluation in rats with adjuvant-induced arthritis. In vivo study included joint diameter measurement, X-ray radiographic analysis, RT-PCR analysis, Western blotting, ELISA for inflammatory markers, and histopathological examination of dissected joints. The particle size and entrapment efficiency of the selected LEF SPION EMLs were 198.2 nm and 83.7%, respectively. The EMLs exhibited sustained release for 24 h. Moreover, in vivo evaluation revealed LEF SPION EMLs to be superior to the LEF suspension, likely due to the increase in LEF solubility by nanoencapsulation that improved the pharmacological effects and the use of SPION that ensured the localization of EMLs in the intra-articular cavity upon administration. [ABSTRACT FROM AUTHOR]

Over the last couple of decades, stimuli-responsive supramolecular gels comprising synthetic short peptides as building blocks have been explored for various biological and material applications. Though a wide range of stimuli has been tested depending on the structure of the peptides, light as a stimulus has attracted extensive attention due to its non-invasive, non-contaminant, and remotely controllable nature, precise spatial and temporal resolution, and wavelength tunability. The integration of molecular photo-switch and low-molecular-weight synthetic peptides may thus provide access to supramolecular self-assembled systems, notably supramolecular gels, which may be used to create dynamic, light-responsive "smart" materials with a variety of structures and functions. This short review summarizes the recent advancement in the area of light-sensitive peptide gelation. At first, a glimpse of commonly used molecular photo-switches is given, followed by a detailed description of their incorporation into peptide sequences to design light-responsive peptide gels and the mechanism of their action. Finally, the challenges and future perspectives for developing next-generation photo-responsive gels and materials are outlined. [ABSTRACT FROM AUTHOR]

In this work, using supramolecular polyurethanes theories, two polycaprolactone-based polyurethanes with 2-ureido-4-[1H]-pyrimidinone (UPy) motifs capable of forming quadruple hydrogen bonds were synthetized and characterized, focusing our attention on their capability to show thermally activated shape-memory response. In particular, 1H NMR analyses confirmed the chemical structure of the supramolecular polyurethanes, while DSC showed their totally amorphous morphology. DMTA in tensile mode was used to study their thermally activated shape-memory properties. In our case, the UPy units are the switching domains while the network formed by the segregated hard segments is the permanent domain obtained materials with excellent shape-memory response at both 100 and 85 °C. These materials are promising for multi-responsive materials where bio-based and potentially recyclable polymers with excellent shape-memory properties are needed. [ABSTRACT FROM AUTHOR]

Traditional open surgery complications are typically due to trauma caused by accessing the procedural site rather than the procedure itself. Minimally invasive surgery allows for fewer complications as microdevices operate through small incisions or natural orifices. However, current minimally invasive tools typically have restricted maneuverability, accessibility, and positional control of microdevices. Thermomagnetic-responsive microgrippers are microscopic multi-fingered devices that respond to temperature changes due to the presence of thermal-responsive polymers. Polymeric devices, made of poly(N-isopropylacrylamide-co-acrylic acid) (pNIPAM-AAc) and polypropylene fumarate (PPF), self-fold due to swelling and contracting of the hydrogel layer. In comparison, soft metallic devices feature a pre-stressed metal bilayer and polymer hinges that soften with increased temperature. Both types of microdevices can self-actuate when exposed to the elevated temperature of a cancerous tumor region, allowing for direct targeting for biopsies. Microgrippers can also be doped to become magnetically responsive, allowing for direction without tethers and the retrieval of microdevices containing excised tissue. The smaller size of stimuli-responsive microgrippers allows for their movement through hard-to-reach areas within the body and the successful extraction of intact cells, RNA and DNA. This review discusses the mechanisms of thermal- and magnetic-responsive microdevices and recent advances in microgripper technology to improve minimally invasive surgical techniques. [ABSTRACT FROM AUTHOR]

Design and fabrication of freestanding chiro‐photonic crystal film with the ability to change color over the whole visible light spectrum is appealing for anticounterfeiting technology and smart labels. Utilizing a newly synthesized light‐responsive molecular motor functionalized with cholesterol (chol‐MM) on the rotor, novel light‐controlled photonic crystal is prepared by doping the novel chol‐MM into liquid crystals (LCs). Thanks to the liquid crystalline cholesterol substituent, the chol‐MM can be triggered by visible light (420 nm). At the same time, the miscibility of chol‐MM in LC matrix is significantly enhanced. Integrating the chol‐MM with thermochromic hydrogen‐bonded LC matrix, thermal and light dual‐responsive cholesteric LC (CLC) material is prepared, in which the nanoscale helical pitch is tunable by photo‐induced molecular motions of chol‐MM. More importantly, utilizing UV‐initiated polymerization of the visible light‐modulated CLC material, structural colored photonic crystal films with arbitrary colorful patterns are fabricated. Such freestanding helical nanostructured labels have potential in the application of encrypted communication and anticounterfeiting. [ABSTRACT FROM AUTHOR]

The present study aimed to develop a stable interconnected matrix as a sustained release drug delivery material. Arabinoxylan (AX) was extracted from ispaghula husk and then crosslinked with different concentrations, i.e., 0.5, 1.0, and 1.5 g of CaCl2 per 0.25 g of AX. The crosslinking was confirmed through Fourier transform infrared spectroscopy. The swelling capacity of crosslinked AX (CL-AX) was evaluated against buffer solutions of pH 1.2, 6.8, 7.4, and water. The swelling capacity increased from pH 1.2 to pH 7.4 and followed the second order swelling kinetics. The swelling study also revealed that CL-AX with 1.0 g CaCl2 showed maximum swelling capacity. The swelling–deswelling (on–off switching) behavior of CL-AX was evaluated in water–ethanol, water–0.9% NaCl solution, and buffer solutions of pH 7.4–1.2 and showed responsive swelling–deswelling behavior. Scanning electron microscopy revealed a highly porous nature of CL-AX with a mesh of thin fibrous networking. Hemocompatibility studies of CL-AX revealed its non-thrombogenic and nonhemolytic attributes. The CL-AX matrix tablet prolonged the release of enalapril maleate for 24 h, and the drug release followed the zero order kinetics and super case-II transport mechanism. Therefore, CL-AX can be recognized as a stimuli responsive and hemocompatible biomaterial with sustained drug release potential. [ABSTRACT FROM AUTHOR]

Protein therapeutics have become increasingly popular for the treatment of a variety of diseases owing to their specificity to targets of interest. However, challenges associated with them have limited their use for a range of ailments, including the limited options available for local controlled delivery. To address this challenge, degradable hydrogel microparticles, or microgels, loaded with model biocargoes were created with tunable release profiles or triggered burst release using chemistries responsive to endogenous or exogeneous stimuli, respectively. Specifically, microfluidic flow-focusing was utilized to form homogenous microgels with different spontaneous click chemistries that afforded degradation either in response to redox environments for sustained cargo release or light for on-demand cargo release. The resulting microgels were an appropriate size to remain localized within tissues upon injection and were easily passed through a needle relevant for injection, providing means for localized delivery. Release of a model biopolymer was observed over the course of several weeks for redox-responsive formulations or triggered for immediate release from the light-responsive formulation. Overall, we demonstrate the ability of microgels to be formulated with different materials chemistries to achieve various therapeutic release modalities, providing new tools for creation of more complex protein release profiles to improve therapeutic regimens. [ABSTRACT FROM AUTHOR]

Bacterial biofilm infections have been threatening the human's life and health globally for a long time because they typically cause chronic and persistent infections. Traditional antibiotic therapies can hardly eradicate biofilms in many cases, as biofilms always form a robust fortress for pathogens inside, inhibiting the penetration of drugs. To address the issues, many novel drug carriers emerged as promising strategies for biofilm treatment. Among them, stimuli-responsive nanocarriers have attracted much attentions for their intriguing physicochemical properties, such as tunable size, shape and surface chemistry, especially smart drug release characteristic. Based on the microenvironmental difference between biofilm infection sites and normal tissue, many stimuli, such as bacterial products accumulating in biofilms (enzymes, glutathione, etc.), lower pH and higher H2O2 levels, have been employed and proved in favor of "on-demand" drug release for biofilm elimination. Additionally, external stimuli including light, heat, microwave and magnetic fields are also able to control the drug releasing behavior artificially. In this review, we summarized recent advances in stimuli-responsive nanocarriers for combating biofilm infections, and mainly, focusing on the different stimuli that trigger the drug release. 摘要: 细菌生物膜常造成长期, 顽固的感染, 因此长久以来都严重威胁着全球人类的生命健康。 由于生物膜会为内部病原体建造其保护性屏障, 阻碍药物的渗透, 因此传统的抗生素疗法通常难以根除生物膜。 为了解决这一问题, 研究人员构建了许多新型的药物载体, 以作为颇具前景的生物膜治疗策略。 其中, 刺激响应型纳米载体具有有趣的物理-化学性质, 例如尺寸, 形状和表面化学可调节的性质, 特别是智能药物释放性质, 因此吸引了人们的广泛关注。 根据生物膜感染位置和正常组织之间的微环境差异, 人们利用多种刺激物, 比如生物膜内积累的细菌产物 (酶, 谷胱甘肽等), 低pH和高H2O2水平, 来设计药物的"按需释放"以清除生物膜。 此外, 包括光, 热, 微波和磁场在内的外源刺激, 也可以用于人工控制药物的释放行为。 本篇综述中, 我们总结了刺激响应型纳米载体在对抗细菌生物膜中的最新进展, 并着重于引发药物释放的多种刺激物。 [ABSTRACT FROM AUTHOR]

Recently, we presented a strategy for packaging peptides as side‐chains in high‐density brush polymers. For this globular protein‐like polymer (PLP) formulation, therapeutic peptides were shown to resist proteolytic degradation, enter cells efficiently and maintain biological function. In this paper, we establish the role charge plays in dictating the cellular uptake of these peptide formulations, finding that peptides with a net positive charge will enter cells when polymerized, while those formed from anionic or neutral peptides remain outside of cells. Given these findings, we explored whether cellular uptake could be selectively induced by a stimulus. In our design, a cationic peptide is appended to a sequence of charge‐neutralizing anionic amino acids through stimuli‐responsive cleavable linkers. As a proof‐of‐concept study, we tested this strategy with two different classes of stimuli, exogenous UV light and an enzyme (a matrix metalloproteinase) associated with the inflammatory response. The key finding is that these materials enter cells only when acted upon by the stimulus. This approach makes it possible to achieve delivery of the polymers, therapeutic peptides or an appended cargo into cells in response to an appropriate stimulus. [ABSTRACT FROM AUTHOR]

Peptide-based drug delivery systems have many advantages when compared to synthetic systems in that they have better biocompatibility, biochemical and biophysical properties, lack of toxicity, controlled molecular weight via solid phase synthesis and purification. Lysosomes, solid lipid nanoparticles, dendrimers, polymeric micelles can be applied by intravenous administration, however they are of artificial nature and thus may induce side effects and possess lack of ability to penetrate the blood-brain barrier. An analysis of nontoxic drug delivery systems and an establishment of prospective trends in the development of drug delivery systems was needed. This review paper summarizes data, mainly from the past 5 years, devoted to the use of peptide-based carriers for delivery of various toxic drugs, mostly anticancer or drugs with limiting bioavailability. Peptide-based drug delivery platforms are utilized as peptide–drug conjugates, injectable biodegradable particles and depots for delivering small molecule pharmaceutical substances (500 Da) and therapeutic proteins. Controlled drug delivery systems that can effectively deliver anticancer and peptide-based drugs leading to accelerated recovery without significant side effects are discussed. Moreover, cell penetrating peptides and their molecular mechanisms as targeting peptides, as well as stimuli responsive (enzyme-responsive and pH-responsive) peptides and peptide-based self-assembly scaffolds are also reviewed. [ABSTRACT FROM AUTHOR]

Donor-acceptor Stenhouse adducts (DASAs) are a photo-switch class that undergoes triene cyclisation in response to visible light. Herein, electrochemical oxidation is demonstrated as an effective alternative stimulus for the triene cyclisation commonly associated with photo-switching. [ABSTRACT FROM AUTHOR]

Microbial growth and fluctuations in environmental conditions have been shown to cause microbial contamination and deterioration of food. Thus, it is paramount to develop reliable strategies to effectively prevent the sale and consumption of contaminated or spoiled food. Responsive packaging systems are designed to react to specific stimuli in the food or environment, such as microorganisms or temperature, then implement an informational or corrective response. Informative responsive packaging is aimed at continuously monitoring the changes in food or environmental conditions and conveys this information to the users in real time. Meanwhile, packaging systems with the capacity to control contamination or deterioration are also of great interest. Encouragingly, corrective responsive packaging attempting to mitigate the adverse effects of condition fluctuations on food has been investigated. This packaging exerts its effects through the triggered release of active agents by environmental stimuli. In this review, informative and corrective responsive packaging is conceptualized clearly and concisely. The mechanism and characteristics of each type of packaging are discussed in depth. This review also summarized the latest research progress of responsive packaging and objectively appraised their advantages. Evidently, the mechanism through which packaging systems respond to microbial contamination and associated environmental factors was also highlighted. Moreover, risk concerns, related legislation, and consumer perspective in the application of responsive packaging are discussed as well. Broadly, this comprehensive review covering the latest information on responsive packaging aims to provide a timely reference for scientific research and offer guidance for presenting their applications in food industry. [ABSTRACT FROM AUTHOR]

Chemotherapy using single drug is not successful now a days due to the emergence of multidrug-resistant cancer cells. In the present work, Methotrexate (MTX) and Mitomycin C (MMC) loaded hydrogel sensitive to both reduction and pH are prepared and well characterized using various instrumentation techniques like FTIR, XRD, SEM and TEM. The drug loading and encapsulation efficiencies (DEE and DLE) of MTX are found to be 90.5 and 54.3% respectively and for MMC the value is 95.1 and 62.7% respectively. Invitro cytotoxicity and Apoptosis studies confirm the increased anticancer activity and selectivity of the novel carrier. [ABSTRACT FROM AUTHOR]

Acid stimulus responsive stealthy nanoparticles were prepared by utilizing three types of copolymers, i.e. acid cleavable polycaprolactone-polyethyleneimine-polyethylene glycol (PCL-PEI-PEG), acid charge reversal polycaprolactone-polyethyleneimine (PCL-PEI), and ligand containing polycaprolactone-polyethyleneimine-folate (PCL-PEI-Fol). FTIR, NMR, and UV-visible spectroscopy confirmed the formation of these copolymers. Acid cleavable property of PCL-PEI-PEG copolymer was examined by FTIR. The formation of nanoparticles was determined by DLS and SEM. Aggregation, structural destabilization, and charge reversibility of nanoparticles at low pH were evaluated by DLS, SEM, and Zeta analyzer, respectively. MTT assay was used to evaluate anticancer effect of nanoparticles. Overall, nanoparticles exhibited improved cytotoxic activity against MCF-7 cancer cells. [ABSTRACT FROM AUTHOR]

Developing safe and efficient delivery systems for therapeutic biomacromolecules is a long‐standing challenge. Herein, we report a newly developed combinatorial library of cholesteryl‐based disulfide bond‐containing biodegradable cationic lipidoid nanoparticles. We have identified a subset of this library which is effective for protein and mRNA delivery in vitro and in vivo. These lipidoids showed comparable transfection efficacies but much lower cytotoxicities compared to the Lpf2k in vitro. In vivo studies in adult mice demonstrated the successful delivery of genome engineering protein and mRNA molecules in the skeletal muscle (via intramuscular injection), lung and spleen (via intravenous injection), and brain (via lateral ventricle infusion). [ABSTRACT FROM AUTHOR]

Developing safe and efficient delivery systems for therapeutic biomacromolecules is a long‐standing challenge. Herein, we report a newly developed combinatorial library of cholesteryl‐based disulfide bond‐containing biodegradable cationic lipidoid nanoparticles. We have identified a subset of this library which is effective for protein and mRNA delivery in vitro and in vivo. These lipidoids showed comparable transfection efficacies but much lower cytotoxicities compared to the Lpf2k in vitro. In vivo studies in adult mice demonstrated the successful delivery of genome engineering protein and mRNA molecules in the skeletal muscle (via intramuscular injection), lung and spleen (via intravenous injection), and brain (via lateral ventricle infusion). [ABSTRACT FROM AUTHOR]

Synthetic materials that mimic the ability of natural occurring features to self‐actuate in response to different stimuli have wide applications in soft robotics, microdevices, drug delivery, regenerative medicine, and sensing. Here, unexpected and counter‐intuitive findings are presented in which a strongly polyelectrolytic hydrogel repels from strong polar solvents upon partial exposure (e.g., partial hydration by water). This repulsion drives the actuation and self‐folding of the gel, which results in rapid formation of different three‐dimensional shapes by simply placing the corresponding two‐dimensional films on water. A detailed investigation into the role of hydrogel chemistry, pH, and morphology on hydration‐triggered actuation behavior of the gels and their nanocomposites is described. Finally, a computational model is developed in order to further elucidate mechanisms of actuation. Modeling partial hydration as a repulsive driving force, it tracks the evolution of the shape of the thin film that results from restoring elastic forces. Taken together, the results indicate that an interplay between elastic and Coulombic repulsive forces leads to seemingly unexpected behavior of actuation of strongly polyelectrolytic gels away from polar solvents, leading to a novel and simple fabrication strategy for diverse 3D devices. [ABSTRACT FROM AUTHOR]

Novel thermal- and pH-responsive hollow nanocapsules (HNCaps) were fabricated through the grafting of a thiol-end capped PNIPAAm-b-PAA by thiol-ene "click" reaction onto PMMA HNCaps. The lowest critical solution temperature (LCST) of the fabricated HNCaps was obtained as 38–40°C. The fabricated nanosystem was loaded with doxorubicin hydrochloride (Dox), and its drug loading and encapsulation efficiencies were obtained as 62 and 53%, respectively. The in vitro stimuli-responsive drug release behavior of the fabricated nanomedicine was investigated extensively. The anticancer activity of the drug-loaded HNCaps was evaluated using MTT assay against MCF7 cells. The results exhibited excellent potential of nanosystem as a drug delivery system (DDS) for cancer chemotherapy. Novel thermal- and pH-responsive poly(methyl metacrylate)-grafted-[poly(N-isopropylacrylamide-block-acrylic acid)] hollow nanocapsules were fabricated as "smart" anticancer drug delivery system (DDS). [ABSTRACT FROM AUTHOR]

Proteinosome, characterized by an inner aqueous cavity wrapped by membrane with embedded protein, is one of the most attractive structures, has huge potential applications on drug delivery, tissue engineering, catalysis, synthetic biology, artificial cells, engineering of the biomachines, biosensors, and biodevices, etc. Here, inspired by polyphenol chemistry, a facile and universal method is presented to fabricate the diverse proteinosomes, with independence on the amino acid sequence, isoelectric points, molecular weight (Mw), wettability, and functional domains of applied proteins. Besides, the materials employed here are green and cost‐effective, and the method developed here is efficient and easily operated without any expensive equipments. The proteinosomes and the mechanism of generating proteinosomes are well characterized and analyzed by various techniques. The permeability of generated proteinosomes is underlined, which not only shows dependence on the applied proteins but also the Mw of diffused molecules. In addition, the permeability can be reversibly switched on/off in 100% by environmental pH. Capitalizing the facility and university of this method, it is believed it paves the way of the proteinosomes to multiple potential applications, such as drug delivery, micro‐/nanoreactors, tissue engineering, catalysis, biosensor, etc. [ABSTRACT FROM AUTHOR]

Conventional tumor-targeted drug delivery systems (DDSs) face challenges, such as unsatisfied systemic circulation, low targeting efficiency, poor tumoral penetration, and uncontrolled drug release. Recently, tumor cellular molecules-triggered DDSs have aroused great interests in addressing such dilemmas. With the introduction of several additional functionalities, the properties of these smart DDSs including size, surface charge and ligand exposure can response to different tumor microenvironments for a more efficient tumor targeting, and eventually achieve desired drug release for an optimized therapeutic efficiency. This review highlights the recent research progresses on smart tumor environment responsive drug delivery systems for targeted drug delivery. Dynamic targeting strategies and functional moieties sensitive to a variety of tumor cellular stimuli, including pH, glutathione, adenosine-triphosphate, reactive oxygen species, enzyme and inflammatory factors are summarized. Special emphasis of this review is placed on their responsive mechanisms, drug loading models, drawbacks and merits. Several typical multi-stimuli responsive DDSs are listed. And the main challenges and potential future development are discussed. [ABSTRACT FROM AUTHOR]

Chemodynamic therapy (CDT) takes the advantages of Fenton‐type reactions triggered by endogenous chemical energy to generate highly cytotoxic hydroxyl radicals. As a novel modality for cancer treatment, CDT shows minimal invasiveness and high tumor specificity by responding to the acidic and the highly concentrated hydrogen peroxide microenvironment of tumor. The CDT approach for spatiotemporal controllable reactive oxygen species generation exhibits preferable therapeutic performance and satisfying biosafety. In this review article, we summarized the recent advances of stimuli‐activatable nanomedicines for CDT. We also overviewed the strategies for augmenting CDT performance, including increasing the catalytic efficacy through rational design of the nanomaterials, modulating the reaction condition, inputting external energy field, and regulating the tumor microenvironment. Furthermore, we discussed the potential and challenges of stimuli‐activatable nanomedicine for clinical translation and future development of CDT. This article is categorized under:Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic DiseaseNanotechnology Approaches to Biology > Nanoscale Systems in BiologyDiagnostic Tools > In Vivo Nanodiagnostics and Imaging [ABSTRACT FROM AUTHOR]

Bioinspired actuators with stimuli-responsive and deformable properties are being pursued in fields such as artificial tissues, medical devices and diagnostics, and intelligent biosensors. These applications require that actuator systems have biocompatibility, controlled deformability, biodegradability, mechanical durability, and stable reversibility. Herein, we report a bionic actuator system consisting of stimuli-responsive genetically engineered silk-elastin-like protein (SELP) hydrogels and wood-derived cellulose nanofibers (CNFs), which respond to temperature and ionic strength underwater by eco-friendly methods. Programmed site-selective actuation can be predicted and folded into three-dimensional (3D) origami-like shapes. The reversible deformation performance of the SELP/CNF actuators was quantified, and complex spatial transformations of multilayer actuators were demonstrated, including a biomimetic flower design with selective petal movements. Such actuators consisting entirely of biocompatible and biodegradable materials will offer an option toward constructing stimuli-responsive systems for in vivo biomedicine soft robotics and bionic research. [ABSTRACT FROM AUTHOR]