pH Response Research Articles

Biopolymeric sensor based on natural deep eutectic solvents for monitoring meat spoilage

Ensuring food safety by monitoring freshness is crucial, particularly for high-protein meat products susceptible to spoilage. Smart packaging with pH-sensitive indicators, using natural pigments such as anthocyanin, provides a cost-effective and non-invasive solution. In this work, a novel colorimetric pH sensor based on biopolymer and natural deep eutectic solvents (NADES) is proposed. The NADES composed by Betaine: Glycerol: Water (BGH) was used for the anthocyanin extraction from Brassica oleracea (Purple Cabbage, PC), using the ultrasonic “one-step” method and BGH extraction efficiency was compared with water. Then, the BGH extract was mixed with different concentrations of xanthan gum (XG) 5, 10, 15 and 20%. The biopolymeric materials were characterized in terms of structure, mechanical properties, stability and pH response. The combination containing 10 % of xanthan gum (PC-BGH-XG10) presented suitable features to be used as a sensor. Thus, PC-BGH-XG10 was applied for real-time monitoring of meat spoilage. Interestingly colour changes were visible to the naked eye and they were successfully correlated with microbiological assays. To the best of our knowledge, this is the first integration of NADES and xanthan gum in the development of a colorimetric pH sensor. The proposed approach represents a green strategy for in-situ control of packaged foods intended for final consumption.

Harnessing chemical functionality of xylan hemicellulose towards carbohydrate polymer-based pH/magnetic dual-responsive nanocomposite hydrogel for drug delivery

This study reports a pH/magnetic dual-responsive hemicellulose-based nanocomposite hydrogel with nearly 100 % carbohydrate polymer-based and biodegradable polymer compositions for drug delivery. We synthesized pure Fe3O4 magnetic nanoparticles (Fe3O4 MNPs) using a co-precipitation method, then engineering xylan hemicellulose (XH), acrylic acid, poly(ethylene glycol) diacrylate, and Fe3O4 to synthesize the pH/magnetic dual-responsive hydrogel (Fe3O4@XH-Gel), through graft polymerization on XH with in-situ doping Fe3O4 MNPs initiated by the ammonium persulfate/tetramethylethylenediamine redox system. Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR), X-ray diffractometry (XRD), scanning electron microscopy and energy dispersive spectrometer (SEM-EDS), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET), swelling gravimetric analysis, vibrating sample magnetometer (VSM) were employed to analyze the hydrogel's chemical structures, morphologies, pH-responsive behaviors, and magnetic responsiveness characteristics, mechanical and rheological properties, as well as cytotoxicity and biodegradability. The results indicate that the Fe3O4@XH-Gel exhibited excellent dual responsiveness to pH and magnetism. Furthermore, an emphasis was placed on the in-depth analysis of the pH response mechanism. Finally, we utilized this cutting-edge hydrogel to investigate the controlled-release behavior of two model drugs, Acetylsalicylic acid and Theophylline. The hydrogel demonstrated exceptional controlled release attributes, positioning it as a potential carrier for targeted drug delivery, particularly to the gastrointestinal conditions.

Genetic background influences mineral accumulation in rice straw and grains under different soil pH conditions

Mineral element accumulation in plants is influenced by soil conditions and varietal factors. We investigated the dynamic accumulation of 12 elements in straw at the flowering stage and in grains at the mature stage in eight rice varieties with different genetic backgrounds (Japonica, Indica, and admixture) and flowering times (early, middle, and late) grown in soil with various pH levels. In straw, Cd, As, Mn, Zn, Ca, Mg, and Cu accumulation was influenced by both soil pH and varietal factors, whereas P, Mo, and K accumulation was influenced by pH, and Fe and Ni accumulation was affected by varietal factors. In grains, Cd, As, Mn, Cu, Ni, Mo, Ca, and Mg accumulation was influenced by both pH and varietal factors, whereas Zn, Fe, and P accumulation was affected by varietal factors, and K accumulation was not altered. Only As, Mn, Ca and Mg showed similar trends in the straw and grains, whereas the pH responses of Zn, P, K, and Ni differed between them. pH and flowering time had synergistic effects on Cd, Zn, and Mn in straw and on Cd, Ni, Mo, and Mn in grains. Soil pH is a major factor influencing mineral uptake in rice straw and grains, and genetic factors, flowering stage factors, and their interaction with soil pH contribute in a combined manner.

Multifunctional skin dressings synthesized via one‐pot photopolymerization: Advancing wound healing and infection prevention strategies

AbstractIn the field of wound healing treatment, the development of new materials is essential to cover multiple functions, such as acceleration of the healing process, prevention of infection and response to stimuli, especially if they present lower costs or are easier to manufacture. These properties are of great importance to prompt skin cicatrization. In this work, new multifunctional skin dressings for wound healing and infection prevention are developed based on new hydrogel materials. The dressings are produced via a straightforward and environmentally friendly one‐pot photopolymerization manufacturing process utilizing vitamin B2 aqueous solutions as sensitizer, and energy‐efficient blue light sources. These dressings exhibit a high swelling capacity, pH and temperature responsiveness, biocompatibility, antimicrobial activity in the absence of conventional antibiotics, and are capable of promoting wound healing. The formulation is based on the combination of three monomers: 2‐((methacryloyloxy)ethyl)trimethylammonium chloride, methacrylic acid and N‐vinyl caprolactam. Collagen, hyaluronic acid, and essential oil of hop are added to enhance antimicrobial properties and stimulate regenerative cellular processes. In vivo experiments have demonstrated that pristine dressings are superior in promoting collagen and fibroblast regeneration and accelerating cicatrization as compared to dressings containing natural products. The dressing embedded with hop also displayed antimicrobial characteristics. The preparation and testing of these new efficient wound dressings are described. This study is distinctive in its integration of environmentally conscious manufacturing techniques with innovative material formulations, resulting in superior wound dressings that are both cost‐effective and highly functional. By achieving enhanced healing and infection prevention without the employment of conventional antibiotics, this work represents a substantial advancement in sustainable and effective wound care management.

Albumin incorporation into recognising layer of HER2-specific magnetic nanoparticles as a tool for optimal targeting of the acidic tumor microenvironment

Cancer is unquestionably a global healthcare challenge, spurring the exporation of novel treatment approaches. In recent years, nanomaterials have garnered significant interest with the greatest hopes for targeted nanoformulations due to their cell-specific delivery, improved therapeutic efficacy, and reduced systemic toxicity for the organism. The problem of successful clinical translation of nanoparticles may be related to the fact that most in vitro tests are performed at pH values of normal cells and tissues, ranging from 7.2 to 7.4. The extracellular pH values of tumors are characterized by a shift to a more acidic region in the range of 5.6–7.0 and represent a crucial target for enhancing nanoparticle delivery to cancer cells. Here we show the method of non-active protein incorporation into the surface of HER2-targeted nanoparticles to achieve optimal cellular uptake within the pH range of the tumor microenvironment. The method efficacy was confirmed in vitro and in vivo showing the maximum binding of nanoparticles to cells at a pH value 6.4. Namely, fluorescent magnetic nanoparticles, modified with HER2-recognising affibody ZHER2:342, with proven specificity in terms of HER2 recognition (with 62-fold higher cellular uptake compared to control nanoparticles) were designed for targeting cancer cells at slightly acidic pH values. The stabilizing protein, namely, bovine serum albumin, one of the major blood components with widespread availability and biocompatibility, was used for the decoration of the nanoparticle surface to alter the pH response of the targeting magnetic conjugates. The optimally designed nanoparticles showed a bell-shaped dependency of interaction with cancer cells in the pH range of 5.6–8.0 with maximum cellular uptake at pH value 6.4 close to that of the tumor microenvironment. In vivo experiments revealed that after i.v. administration, BSA-decorated nanoparticles exhibited 2 times higher accumulation in tumors compared to magnetic nanoparticles modified with affibody only. Thus, we demonstrated a valid method for enhancing the specificity of targeted nanoparticle delivery to cancer cells without changing the functional components of nanoparticles.

An Insulin-Modified pH-Responsive Nanopipette Based on Ion Current Rectification.

The properties of nanopipettes largely rely on the materials introduced onto their inner walls, which allow for a vast extension of their sensing capabilities. The challenge of simultaneously enhancing the sensitivity and selectivity of nanopipettes for pH sensing remains, hindering their practical applications. Herein, we report insulin-modified nanopipettes with excellent pH response performances, which were prepared by introducing insulin onto their inner walls via a two-step reaction involving silanization and amidation. The pH response intensity based on ion current rectification was significantly enhanced by approximately 4.29 times when utilizing insulin-modified nanopipettes compared with bare ones, demonstrating a linear response within the pH range of 2.50 to 7.80. In addition, insulin-modified nanopipettes featured good reversibility and selectivity. The modification processes were monitored using the I-V curves, and the relevant mechanisms were discussed. The effects of solution pH and insulin concentration on the modification results were investigated to achieve optimal insulin introduction. This study showed that the pH response behavior of nanopipettes can be greatly improved by introducing versatile molecules onto the inner walls, thereby contributing to the development and utilization of pH-responsive nanopipettes.

Optimizing alginate dressings with allantoin and chemical modifiers to promote wound healing

Wound healing requires diverse functionalities in dressings, and conventional materials often fall short in water absorption and moisture regulation. Natural sodium alginate is popular in wound dressings due to its excellent film-forming ability, biocompatibility, ionic crosslinking, and pH responsiveness. However, it has limitations in physical stability and solubility in aqueous environments. This study enhanced alginate dressings by incorporating allantoin and treating with calcium chloride and citric acid to improve physicochemical properties and mechanical performance. Treatments for S2 to S5 prevented dissociation and maintained integrity, with suitable water absorption (363 %–442 %) and water vapor transmission rates (612.53–715.39 g × m2 × day−1). The treatments also improved tensile strength (44.90–55.19 MPa). S2 had the highest migration ratio (52.71 %) of L929 cells and wound healing rates for mice skin (86.6 %), indicating that calcium chloride treatment is beneficial. All dressings (S1 to S5) exhibited low cytotoxicity against L929 cells and low hemolysis ratios, indicating good biocompatibility. Higher allantoin content improved wound healing efficacy. This study provides valuable insights for the design and development of alginate dressings in wound repair, expanding allantoin's application in wound healing.

Copper peroxide loaded gelatin/oxide dextran hydrogel with temperature and pH responsiveness for antibacterial and wound healing activity

Bacterial infection and tissue hypoxia always prevent wound healing, so multifunctional platforms with antimicrobial and oxygen-supplying functions were developed. However, they face many difficulties such as complex preparation and low oxygen release. To address this challenge, a copper peroxide loaded gelatin/oxide dextran hydrogel (CGO) was prepared. Surprisingly, CGO hydrogel as a wound dressing not only had good biocompatibility, injectivity, and mechanical properties, but also exhibited mild photothermal properties, temperature responsiveness, and pH responsiveness. After being applied to wounds infected with bacteria, CGO hydrogel released copper peroxide under near-infrared laser irradiation, which produced copper ions and hydrogen peroxide, combined with PTT to kill bacteria. After the bacteria were cleared from the wound and the pH of the wound was changed to be acidic, CGO hydrogel released copper peroxide via pH response. Copper ions and oxygen produced from copper peroxide accelerated wound healing by promoting angiogenesis. The multi-responsive and multi-mode treatment platform provided a potential strategy for treating bacteria-infected wounds.

Synthesis, characterization and stability of crosslinked chitosan-maltodextrin pH-sensitive nanogels

Polysaccharide-based nanogels offer a wide range of chemical compositions and are of great interest due to their biodegradability, biocompatibility, non-toxicity, and their ability to display pH, temperature, or enzymatic response. In this work, we synthesized monodisperse and tunable pH-sensitive nanogels by crosslinking, through reductive amination, chitosan and partially oxidized maltodextrins, by keeping the concentration of chitosan close to its overlap concentration, i.e. in the dilute and semi-dilute regime. The chitosan/maltodextrin nanogels presented sizes ranging from 63 ± 9 to 279 ± 16 nm, showed quasi-spherical and cauliflower-like morphology, reached a ζ-potential of +36 ± 2 mV and maintained a colloidal stability for up to 7 weeks. It was found that the size and surface charge of nanogels depended both on the oxidation degree of maltodextrins and chitosan concentration, as well as on its degree of acetylation and protonation, the latter tuned by pH. The pH-responsiveness of the nanogels was evidenced by an increased size, owed to swelling, and ζ-potential when pH was lowered. Finally, maltodextrin-chitosan biocompatible nanogels were assessed by cell viability assay performed using the HEK293T cell line.

Keratin-PNIPAM Hybrid Microgels: Preparation, Morphology and Swelling Properties.

Combinations of synthetic polymers, such as poly(N-isopropylacrylamide) (PNIPAM), with natural biomolecules, such as keratin, show potential in the field of biomedicine, since these hybrids merge the thermoresponsive properties of PNIPAM with the bioactive characteristics of keratin. This synergy aims to produce hybrids that can respond to environmental stimuli while maintaining biocompatibility and functionality, making them suitable for various medical and biotechnological uses. In this study, we exploit keratin derived from wool waste in the textile industry, extracted via sulfitolysis, to synthesize hybrids with PNIPAM microgel. Utilizing two distinct methods-polymerization of NIPAM with keratin (HYB-P) and mixing preformed PNIPAM microgels with keratin (HYB-M)-resulted in hybrids with 20% and 25% keratin content, respectively. Dynamic light scattering (DLS) and transmission electron microscopic (TEM) analyses indicated the formation of colloidal systems with particle sizes of around 110 nm for HYB-P and 518 nm for HYB-M. The presence of keratin in both systems, 20% and 25%, respectively, was confirmed by spectroscopic (FTIR and NMR) and elemental analyses. Distinct structural differences were observed between HYB-P and HYB-M, suggesting a graft copolymer configuration for the former hybrid and a complexation for the latter one. Furthermore, these hybrids demonstrated temperature responsiveness akin to PNIPAM microgels and pH responsiveness, underscoring their potential for diverse biomedical applications.

A novel pH-sensitive drug carrier system based on 18-crown ether-6/sodium alginate for curcumin/nido-carborane encapsulation: Studies of release properties, cell imaging and bioactivity evaluation

Curcumin's remarkable anti-tumor action has drawn a lot of interest, however its low bioavailability, poor targeting, and poor water solubility restrict its therapeutic potential. Two fluorescent polymers based on curcumin/nido-carborane-crown ether were produced using a two-phase technique in this study: Cur/Carborane-C/SA (encapsulated with sodium alginate) and Cur/Carborane-C (without sodium alginate). Cur/Carborane-C/SA was thought to be the most promising polymer with anti-tumor properties. The drug delivery method based on the polymer created by tris (3-aminoethyl) amine (TAEA) and 18-crown ether-6 in combination with sodium alginate offers a novel approach to curcumin encapsulation technology. Nido-carborane improves the targeting of curcumin and its tumor-cell-inhibiting properties. Good fluorescence qualities were shown by Cur/Carborane-C/SA's fluorescence quantum yield of 0.119 %. According to in vitro drug release data, the polymer performed well for pH response release at 5.0. The TEM and particle size data demonstrated that curcumin produced uniformLy sized, difficult to agglomerate nanoparticles with a particle size of less than 300 nm. The polymer exhibited a substantial affinity and inhibition of HCT-116 and HeLa cells, with an inhibition rate that may reach 78.3 %, according to the findings of the cytotoxicity assay and cell imaging. As a result, it is anticipated that the produced Cur/Carborane-C/SA would provide a new pH-responsive drug carrier system for curcumin intended for use in cancer treatment.

Bridging papermaking and hydrogel production: Nanoparticle-loaded cellulosic hollow fibers with pitted walls as skeleton materials for multifunctional electromagnetic hydrogels

Electromagnetic hydrogels have attracted significant attention due to their vast potential in soft robotics, biomedical engineering, and energy harvesting. To facilitate future commercialization via large-scale industrial processes, we present a facile concept that utilizes the specialized knowledge of papermaking to fabricate hydrogels with multifunctional electromagnetic properties. The principles of papermaking wet end chemistry, which involves the handling of interactions among cellulosic fibers, fines, polymeric additives, and other components in aqueous systems, serves as a key foundation for this concept. Notably, based on these principles, the versatile use of chemical additives in combination with cellulosic materials enables the tailored design of various products. Our methodology exploits the unique hierarchically pitted and hollow tube-like structures of papermaking grade cellulosic fibers with discernible pits, enabling the incorporation of magnetite nanoparticles through lumen loading. By combining microscale softwood-derived cellulosic fibers with additives, we achieve dynamic covalent interactions that transform the cellulosic fiber slurry into an impressive hydrogel. The cellulosic fibers act as a skeleton, providing structural support within the hydrogel framework and facilitating the dispersion of nanoparticles. In accordance with our concept, the typical hydrogel exhibits combined attributes, including electrical conductivity, self-healing properties, pH responsiveness, and dynamic rheologic behavior. Our approach not only yields hydrogels with interesting properties but also aligns with the forefront of advanced cellulosic material applications. These materials hold the promise in remote strain sensing devices, electromagnetic navigation systems, contactless toys, and flexible electronic devices. The concept and findings of the current work may shed light on materials innovation based on traditional pulp and paper processes. Furthermore, the facile processes involved in hydrogel formation can serve as valuable tools for chemistry and materials education, providing easy demonstrations of principles for university students at different levels.

Theranostic nanoparticles ZIF-8@ICG for pH/NIR-responsive drug-release and NIR-guided chemo-phototherapy against non-small-cell lung cancer

This study leverages nanotechnology by encapsulating indocyanine green (ICG) and paclitaxel (Tax) using zeolitic imidazolate frameworks-8 (ZIF-8) as a scaffold. This study aims to investigate the chemo-photothermal therapeutic potential of ZIF-8@ICG@Tax nanoparticles (NPs) in the treatment of non-small cell lung cancer (NSCLC). An “all-in-one” theranostic ZIF-8@ICG@Tax NPs was conducted by self-assembly based on electrostatic interaction. First, the photothermal effect, stability, pH responsiveness, drug release, and blood compatibility of ZIF-8@ICG@Tax were evaluated through in vitro testing. Furthermore, the hepatic and renal toxicity of ZIF-8@ICG@Tax were assessed through in vivo testing. Additionally, the anticancer effects of these nanoparticles were investigated both in vitro and in vivo. Uniform and stable chemo-photothermal ZIF-8@ICG@Tax NPs had been successfully synthesized and had outstanding drug releasing capacities. Moreover, ZIF-8@ICG@Tax NPs showed remarkable responsiveness dependent both on pH in the tumor microenvironment and NIR irradiation, allowing for targeted drug delivery and controlled drug release. NIR irradiation can enhance the tumor cell response to ZIF-8@ICG@Tax uptake, thereby promoting the anti-tumor growth in vitro and in vivo. ZIF-8@ICG@Tax and NIR irradiation have demonstrated remarkable synergistic anti-tumor growth properties compared to their individual components. This novel theranostic chemo-photothermal NPs hold great potential as a viable treatment option for NSCLC.Graphical A novel nano-theranostic platform was developed by encapsulating indocyanine green and paclitaxel within a zeolitie imidazolate framework-8 (ZIF-8). This chemo-phototherapic agent demonstrated accurate tumor targeting and effective suppression effects on both tumor growth in non-small cell lung cancer.

A dual-signals fluorometric and colorimetric peptide-based probe for Cu(II) and glyphosate detection and its application for bioimaging and water testing

A novel dual-signal fluorometric and colorimetric probe FMDH (5-FAM-Met-Asp-His-NH2), incorporating a tripeptide (Met-Asp-His-NH2) linked to 5-carboxyfluorescein (5-FAM), was firstly synthesised. FMDH demonstrated exceptional selectivity and sensitivity, rapid response, wide pH response range and robust anti-interference capabilities for monitoring Cu2+. This was achieved through a distinctive naked-eye colorimetric and fluorescent quenching behaviour. A good linearity within the range of 0–3 μM (R2 = 0.9914) was attained, and the limit of detection (LOD) for Cu2+ was 47.4 nM. Furthermore, the FMDH-Cu2+ ensemble responded to glyphosate with notable selectivity and sensitivity. A good linear correlation (R2 = 0.9926) was observed at the lower concentration range (2.4–7.8 μM) and achieving a detection limit as low as 29.9 nM. The response time of FMDH with Cu2+ and glyphosate were less than 20 s, and the pH range of 7–11 that was suitable for practical application under physiological pH conditions. MTT assays confirmed that FMDH offers good permeability and low toxicity, facilitating successful application in imaging analysis of Cu2+ and glyphosate in living cells and zebrafish. In addition, FMDH was employed in the detection of these analytes in real water samples. Cost-effective, highly sensitive and easily prepared FMDH-impregnated test strips were developed for the efficient visual detection of Cu2+ and glyphosate under 365 nm UV light. Increasing concentrations of Cu2+ and glyphosate resulted in notable colour changes under 365 nm UV light, enabling visual semi-quantitative analysis via a smartphone colour-analysis App.

Construction of biomimetic camouflaged neutrophil membrane nanoparticles for precise delivery and augmented glioma cancer treatment

Developing novel nanomedicine formulations that successfully penetrate the blood-brain barrier (BBB) to treat and diagnose glioma effectively is still a significant obstacle. This study presents the development of polymer nanogels camouflaged with macrophage membranes. The nanogels are loaded with manganese dioxide (MnO2) and carboplatin. They are designed for the treatment of glioma using a combination of chemotherapy and chemodynamic therapy (CDT). The precipitation polymerization process was used to create redox-responsive poly(caprolactone) (PCL) nanogels (NGs). These NGs were then loaded with MnO2 and physically encapsulated with carboplatin. The resulting nanogels had an average diameter of 102.52 nm and were covered with macrophage membranes to provide excellent stability. The developed NGs exhibit redox and pH responsiveness, releasing carboplatin and Mn(II) in a controlled manner. NGs may effectively deplete glutathione (GSH) in the tumour milieu. The Mn(II) generated in this process enhances the effectiveness of the loaded carboplatin by exerting its chemotherapeutic action and promoting the formation of reactive oxygen species to improve the efficiency of CDT. The results of our study show a very efficient and promising nanomedicine platform for the treatment and diagnosis of glioma, a type of cancer. This platform is self-adaptive, cooperative, and based on NG technology. Furthermore, this platform can potentially be used for other challenging types of cancer.

Smart hydrogel catalyst with tunable activity for 4-nitrophenol reduction at different temperatures and pH

In this study, a novel method is introduced for preparing the poly (N-isopropylacrylamideco-methacrylic acid) (PNIPAM) hydrogel catalyst (PNMC-Ag) with embedded silver nanoparticles (Ag NPs), by employing in situ reduction of Ag+ in polymeric network. The prepared hydrogel catalyst exhibits both thermal and pH responsiveness, facilitating precise control of catalytic efficiency in reducing pollutants such as 4-nitrophenol (4-NP) under varying environmental conditions. The embedded Ag NPs demonstrate remarkable stability against self-aggregation due to their confinement within the polymeric network, thus maintaining their exceptional catalytic performance over time. Leveraging the dual-responsive nature of the PNMC-Ag catalyst, tunable catalytic activity can be achieved by adjusting the temperature and pH of the reaction environment. Specifically, the Ag NPs-hydrogel catalyst exhibits high catalytic activity (21 min, 98.5%) in low-temperature ([Formula: see text]< 32°C) at neutral pH and alkaline (pH = 9) conditions at room temperature, while its activity is attenuated in high-temperature ([Formula: see text]> 32°C) at neutral pH or acidic (pH [Formula: see text]4) environments at room temperature owing to the hydrogel’s thermal and pH-responsive characteristics. This distinctive feature enables precise control over the catalytic reaction, offering an effective approach for the removal of 4-NP from wastewater using a noble-metal-containing stimuli-responsive hydrogel (SRH) catalyst. Overall, this work represents a significant step towards the development of intelligent catalytic materials with superior environmental remediation capabilities.

Dual electro-/pH-responsive nanoparticle/hydrogel system for controlled delivery of anticancer peptide

An electro-chemo-responsive carrier has been engineered for the controlled release of a highly hydrophilic anticancer peptide, CR(NMe)EKA (Cys-Arg- N-methyl-Glu-Lys-Ala). Remotely controlled on demand release of CR(NMe)EKA, loaded in electro-responsive poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles, has been achieved by applying electrical stimuli consisting of constant positive (+0.50 V) or negative voltages (−0.50 V) at pre-defined time intervals. In addition, after loading CR(NMe)EKA/PEDOT nanoparticles into an injectable pH responsive hydrogel formed by phenylboronic acid grafted to chitosan (PBA-CS), the efficiency of the controlled peptide release has increased approximately by a factor of 2.6. The hydration ratio of such hydrogel is significantly lower in acidic environments than in neutral and basic media, which has been attributed to the dissociation of the boronate bonds between polymer chains. Hence, the electro-controlled peptide release from PBA-CS/CR(NMe)EKA/PEDOT hydrogels, in the acidic environment of tumors, combines the effects of the oxidation and reduction of PEDOT chains on the interactions with the peptide and the carrier, with the peptide concentration gradient at the interface between the collapsed hydrogel and the release medium. Furthermore, the peptide released by electro-stimulation preserved its bioactivity assessed by promoting human prostate cancer cells death. Overall, this work is a promising attempt to develop a carrier platform for small hydrophilic anticancer peptides, which delivery rationale is synergistically regulated by the electrical and pH responsiveness of the carrier.

Preparation of microencapsulated phase change materials for use in feminine hygiene napkins based on pH response

Preparation of microencapsulated phase change materials for use in feminine hygiene napkins based on pH response

A Promising Compound for Green Multiresponsive Materials Based on Acyl Carrier Protein.

A gel that exhibits intrinsically multiple-responsive behavior was prepared from an oligopeptide and studied. ACP(65-74) is an active decapeptide fragment of acyl carrier protein. We investigated 3% w/v ACP(65-74)-NH2 self-healing physical gels in water, glycerol carbonate (GC), and their mixtures. The morphology was investigated by optical, birefringence, and confocal laser scanning microscopy, circular dichroism, Fourier transform infrared, and fluorescence spectroscopy experiments. We found that all samples possess pH responsiveness with fully reversible sol-to-gel transitions. The rheological properties depend on the temperature and solvent composition. The temperature dependence of the gels in water shows a peculiar behavior that is similar to that of thermoresponsive polymer solutions. The results reveal the presence of several β-sheet structures and amyloid aggregates, offering valuable insights into the fibrillation mechanism of amyloids in different solvent media.

In Situ Preparation of Star-Shaped Protein-"Smart" Polymer Conjugates with pH and Thermo-Dual Responsibility for Bacterial Separation.

To achieve effective separation and enrichment of bacteria, a novel synthetic scheme was developed to synthesize star-style boronate-functionalized copolymers with excellent hydrophilicity and temperature and pH responsiveness. A hydrophilic copolymer brush was synthesized by combining surface-initiated atom-transfer radical polymerization with amide reaction using bovine serum albumin as the core. The copolymer brush was further modified by introducing and immobilizing fluorophenylboronic acids through an amide reaction, resulting in the formation of boronate affinity material BSA@poly(NIPAm-co-AGE)@DFFPBA. The morphology and organic content of BSA@poly(NIPAm-co-AGE)@DFFPBA were systematically characterized. The BSA-derived composites demonstrated a strong binding capacity to both Gram-positive and Gram-negative bacteria. The binding capabilities of the affinity composite to Staphylococcus aureus and Salmonella spp. were 195.8 × 1010 CFU/g and 79.2 × 1010 CFU/g, respectively, which indicates that the novel composite exhibits a high binding capability to bacteria and shows a particularly more significant binding capacity toward Gram-positive bacteria. The bacterial binding of BSA@poly(NIPAm-co-AGE)@DFFPBA can be effectively altered by adjusting the pH and temperature. This study demonstrated that the star-shaped affinity composite had the potential to serve as an affinity material for the rapid separation and enrichment of bacteria in complex samples.