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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]

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.

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]

Abstract Smart molecules have attracted increasing attention due to their transformative role in creating the next generation of smart structures and devices. Smart bistable coordination complexes are a class of functional complexes which have two stable states that can be reversibly switched in response to external stimuli. Such bistable molecules play a vital role in various applications, such as sensors, data storage, spintronics, smart windows, optical switches, information encryption and decryption, displays, actuators, etc. Herein, the recent research studies into the development of these smart bistable metal coordination complexes are reviewed. According to the different external stimuli, these smart bistable coordination systems have been classified and summarized, including light‐responsive systems, thermally‐responsive systems, electrically‐responsive systems, mechanically‐responsive systems, and some other cases. These systems are further subdivided according to the changes in signals (e.g., color, fluorescence, spin state, crystalline phase) under external stimuli. The design principles of each type of smart bistable metal complexes as well as their broad and innovative applications are comprehensively described. Finally, the challenges and opportunities in this field are briefly analyzed and discussed.

Abstract Chirality is a fundamental property in nature, which is essential for the existence and survival of living organisms. Smart responsive chiroptical materials have garnered increasing attention due to their unique structural characteristics and potential applications. Among these, azobenzene (Azo), as a typical photoresponsive chromophore, plays a crucial role in constructing and controlling chiral structures. The unique cis‐trans isomerization, liquid crystallinity, and other physicochemical properties allow for a wide range of tunability in stimuli‐responsive chiroptical materials. Herein, we review the research studies in the field of chiral/achiral Azo building blocks for multilevel chiral generation as well as chiral switching, and summarize the recent advances on the applications of the chiral Azo structures from micro to macro levels. Finally, we aim to provide an overview of the potential challenges and new research opportunities for the development of novel smart responsive chiroptical materials.

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.

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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]

We previously reported that amphiphilic peptides containing one Lys and two His in the hydrophilic domain—KHHAAAAAA7 (KHHA7)—formed ternary complexes with intermediate metal ions and a poorly water-soluble anticancer drug—paclitaxel (Ptx)—which improved the water dispersibility of Ptx. In this study, the effect of ternary complexes of KHHA7 on cell viability is evaluated in vitro using HeLa cells. The ternary complexes reduced the cell viability by approximately 60%, suggesting that complex formation enhanced the cytotoxicity by increasing the water dispersibility of Ptx. Furthermore, the novel amphiphilic short peptides KHHAAAAAAW (KHHA6W) and KHHAAAWAAA (KHHA3WA3) were synthesized by Fmoc solid phase synthesis as dispersants for Ptx. These peptides differed from KHHA7 owing to the presence or absence of Trp and its position. The change in amino acid residues from Ala to Trp and the position of Trp in the hydrophobic domain of the amphiphilic peptide had little effect on the water dispersibility of Ptx.

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]

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]

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]

The complexity of the tumor microenvironment (TME) severely hinders the therapeutic effects of various cancer treatment modalities. The TME differs from normal tissues owing to the presence of hypoxia, low pH, and immune-suppressive characteristics. Modulation of the TME to reverse tumor growth equilibrium is considered an effective way to treat tumors. Recently, polymeric nanomedicines have been widely used in cancer therapy, because their synthesis can be controlled and they are highly modifiable, and have demonstrated great potential to remodel the TME. In this review, we outline the application of various stimuli responsive polymeric nanomedicines to modulate the TME, aiming to provide insights for the design of the next generation of polymeric nanomedicines and promote the development of polymeric nanomedicines for cancer therapy.

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.

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]

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.

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.

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]

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]

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]

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]

[Display omitted] Cesium lead halide perovskite quantum dots (QDs) have attracted immense attention for luminescent materials due to their narrow emission bands and color-tunable emission. However, indispensable surface ligands originating from ligand-assisted synthesis strategies severely deteriorate the stability and luminescence properties of QDs since these ligands have a highly dynamic binding. Herein, we used a green fluorescence BODIPY molecule containing thiol (named SH-BDP) to regulate the CsPbBr 3 QDs surface by ligand regulation. Density functional theory calculations proved that the SH-BDP molecule could bind to the exposed Pb of CsPbBr 3 QDs stronger than traditional ligands to form stable SH-BDP-QDs. Moreover, the SH-BDP fixed on the CsPbBr 3 QDs surface can improve water and light resistance. It also served as a knob to tune their luminescence properties and the reversible thermal-stimuli response. Finally, the multi-response property of SH-BDP-QDs was realized under polar solvent or heat along with UV light. In addition, we used the SH-BDP-QDs to create various anti-counterfeiting labels; several luminous modes were achieved under different external stimuli, which improved the quality of the optical anti-counterfeiting labels and ensured information security. This work indicates the immense potential of surface ligand manipulation in improving the stability and multi-stimuli-responsive optical encoding of perovskite quantum dots. [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]

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]

Biologically occurring non-canonical di-α-amino acids were converted into new di-N-carboxyanhydride (di-NCA) monomers in reasonable yields with high purity. Five different di-NCAs were separately copolymerized with tert-butyl-l-glutamate NCA to obtain covalently crosslinked copolypeptides capable of forming hydrogels with varying crosslinker density. Comparison of hydrogel properties with residue structure revealed that different di-α-amino acids were not equivalent in crosslink formation. Notably, l-cystine was found to produce significantly weaker hydrogels compared to l-homocystine, l-cystathionine, and l-lanthionine, suggesting that l-cystine may be a sub-optimal choice of di-α-amino acid for preparation of copolypeptide networks. The di-α-amino acid crosslinkers also provided different chemical stability, where disulfide crosslinks were readily degraded by reduction, and thioether crosslinks were stable against reduction. This difference in response may provide a means to fine tune the reduction sensitivity of polypeptide biomaterial networks.

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]

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]

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]