Antiblood Cell Adhesion of Mussel-Inspired Chondroitin Sulfate- and Caffeic Acid-Modified Polycarbonate Membranes.

We fabricated a mussel-inspired hemocompatible polycarbonate membrane (PC) modified by the cross-linking of chondroitin sulfate and caffeic acid polymer using CA-CS via a Schiff base and Michael addition reaction and named it CA-CS-PC. The as-fabricated CA-CS-PC membrane shows excellent hydrophilicity with a water contact angle of 0° and a negative surface charge with a zeta potential of -32 mV. The antiadhesion property of the CA-CS-modified PC membrane was investigated by enzyme-linked immunosorbent assay (ELISA), using human plasma protein fibrinogen adsorption studies, and proved to have excellent antiadhesion properties, because of the lower fibrinogen adsorption. In addition, the CA-CS-PC membrane also shows enhanced hemocompatibility. Finally, blood cell attachment tests of the CA-CS-PC membrane were observed by CLSM and SEM, and the obtained results proved that CA-CS-PC effectively resisted cell adhesion, such as platelets and leucocytes. Therefore, this work disclosed a new way to design a simple and versatile modification of the membrane surface by caffeic acid and chondroitin sulfate and apply it for cell adhesion.

Plasmonic surface-enhanced Raman scattering nano-substrates for detection of anionic environmental contaminants: Current progress and future perspectives.

Surface-enhanced Raman scattering spectroscopy (SERS) is a powerful technique of vibrational spectroscopy based on the inelastic scattering of incident photons by molecular species. It has unique properties such as ultra-sensitivity, selectivity, non-destructivity, speed, and fingerprinting properties for analytical and sensing applications. This enables SERS to be widely used in real-world sample analysis and basic plasmonic mechanistic studies. However, the desirable properties of SERS are compromised by the high cost and low reproducibility of the signals. The development of multifunctional, stable and reusable nano-engineered SERS substrates is a viable solution to circumvent these drawbacks. Recently, plasmonic SERS active nano-substrates with various morphologies have attracted the attention of researchers due to promising properties such as the formation of dense hot spots, additional stability, tunable and controlled morphology, and surface functionalization. This comprehensive review focused on the current advances in the field of SERS active nanosubstrates suitable for the detection and quantification of anionic environmental pollutants. The common fabrication methods, including the techniques for morphological adjustments and surface modification, substrate categories, and the design of nanotechnologically fabricated plasmonic SERS substrates for anion detection are systematically presented. Here, the need for the design, synthesis, and functionalization of SERS nano-substrates for anions of great environmental importance is explained in detail. In addition, the broad categories of SERS nano-substrates, namely colloid-based SERS substrates and solid-support SERS substrates are discussed. Moreover, a brief discussion of SERS detection of certain anionic pollutants in the environment is presented. Finally, the prospects in the fabrication and commercialization of pilot-scale handheld SERS sensors and the construction of smart nanosubstrates integrated with novel amplifying materials for the detection of anions of environmental and health concern are proposed.

Fluorine-Free Superhydrophobic Covalent-Organic-Polymer Nanosheet Coating for Selective Dye and Emulsion Separation.

Covalent organic polymer nanosheets (COPNs) endowed with porous networks and large surface areas in their structures offer great advantages over other materials in addressing environmental problems. In this study, fluorine-free superhydrophobic COPNs were designed and applied to selective dye absorption. Notably, COPNs selectively adsorb dyes with a high hydrophobic index (HI) and reject low HI dyes with maximum adsorption capacities of 361 and 263 mg/g for crystal violet and methylene blue, respectively. The adsorption isotherm model showed that the COPNs follow the Langmuir adsorption isotherm model and pseudo-second-order kinetics. Next, we explored the superhydrophobicity of the COPNs by in situ fabrication with melamine sponge (COPNs-MS), which incorporates the superhydrophobicity of COPNs [water contact angle (WCA) of >150°] with the structure and flexibility of the MS skeleton. The COPNs-MS shows various oil-adsorbing properties with good adsorption capacity (from 60 to 120 g/g) and also effectively separates various surfactant-stabilized emulsions with a separation efficiency of over 99%. The as-fabricated COPNs-MS retains its superhydrophobicity in various solvents and hazardous conditions (WCA ≥ 150°) and exhibits good flame retardancy and excellent compression properties with excellent antifouling property due to the superhydrophobic COPN coating. Furthermore, COPNs-MS also demonstrates excellent recyclability because the strong COPN coating in the MS skeleton retains its hydrophobicity. Therefore, our fluorine-free superhydrophobic COPNs are not only capable of selective dye adsorption but also exhibit very good oil adsorption and surfactant-stabilized emulsion separation performance.

Preparation of thermosensitive PNIPAm-based copolymer coated cytodex 3 microcarriers for efficient nonenzymatic cell harvesting during 3D culturing.

Enzymatic detachment of cells might damage important features and functions of cells and could affect subsequent cell-based applications. Therefore, nonenzymatic cell detachment using thermosensitive polymer matrix is necessary for maintaining cell quality after harvesting. In this study, we prepared thermosensitive PNIPAm-co-AAc-b-PS and PNIPAm-co-AAm-b-PS copolymers and low critical solution temperature (LCST) was tuned near to body temperature. Then, spin coated polymer films were prepared for cell adhesion and thermal-induced cell detachment. The alpha-step analysis and scanning electron microscope image of the films suggested that the thickness of the films depends on the molecular weight and concentration which ranged from 206 to 1330 nm for PNIPAm-co-AAc-b-PS and 97.5-497 nm for PNIPAm-co-AAm-b-PS. The contact angles of the films verified that the polymer surface was moderately hydrophilic at 37°C. Importantly, RAW264.7 cells were convincingly proliferated on the films to a confluent of >80% within 48 h and abled to detach by reducing the temperature. However, relatively more cells were grown on PNIPAm-co-AAm-b-PS (5%w/v) films and thermal-induced cell detachment was more abundant in this formulation. As a result, PNIPAm-co-AAm-b-PS (5%w/v) was further used to coat commercial cytodex 3 microcarriers for 3D cell culturing and interestingly enhanced cell detachment with preserved potential of recovery was observed at a temperature of below LCST. Thus, surface modification of microcarriers with thermosensitive PNIPAm-co-AAm-b-PS could be vital strategy for nonenzymatic cell detachment and to achieve adequate number of cells with maximum cell viability and functionality.

PAMAM G4.5 dendrimers for targeted delivery of ferulic acid and paclitaxel to overcome P-glycoprotein-mediated multidrug resistance.

In this study, we prepared ferulic acid (FA) and paclitaxel (PTX) co-loaded polyamidoamine (PAMAM) dendrimers conjugated with arginyl-glycyl-aspartic acid (RGD) to overcome P-glycoprotein (P-gp)-mediated multidrug resistance (MDR). FA was released in greater extent (80%) from the outer layer of the dendrimers compared with PTX (70%) from the interior of the dendrimers. FA improved intracellular availability of PTX via P-gp modulation in drug-resistant cells. In vitro drug uptake data show higher PTX delivery with RGD-PAMAM-FP than with PAMAM-FP in drug resistant KB CH-R 8-5 cell lines. This indicates that RGD facilitates intracellular PTX accumulation through active targeting in multidrug-resistant KB CH-R 8-5 cells. The terminal deoxynucleotidyl transferase 2'-deoxyuridine 5'-triphosphate nick-end labeling assay data and membrane potential analysis in mitochondria confirm the enhanced anticancer potential of RGD-PAMAM-FP nanoaggregates in drug-resistant cells. We also confirmed by the increased protein levels of proapoptotic factors such as caspase 3, caspase 9, p53, and Bax after treatment with RGD-PAMAM-FP nanoaggregates and also downregulates antiapoptotic factors. Hence, FA-PTX co-loaded, RGD-functionalized PAMAM G4.5 dendrimers may be considered as an effective therapeutic strategy to induce apoptosis in P-gp-overexpressing, multidrug-resistant cells.

Amperometric determination of ecotoxic N-methyl-p-aminophenol sulfate in photographic solution and river water samples based on graphene oxide/CeNbO4 nanocomposite catalyst.

The electronic conductivity of the metal oxides is generally increased by hybridization of highly conductive carbon supportive materials. In this present work, we have demonstrated a novel one-pot preparation of cerium niobate (CeNbO4) nanoparticles embedded with graphene oxide (GO/CeNbO4) composite, for ultrasensitive detection of the photographic developing agent, metol (MTL). The as-prepared GO/CeNbO4 was analyzed by various characterization techniques. The intensive characterization techniques were used to affirm the detailed structural moiety, size, morphology, and surface area of GO/CeNbO4. The GO/CeNbO4 modified glassy carbon electrode (GCE) affords a superior electrocatalytic activity toward MTL. The obtained amperometric response on the GO/CeNbO4/GCE holding an extremely low level detection of 10 nM and superior sensitivity of 10.97 µA µM-1 cm-2 toward MTL detection. Besides, the GO/CeNbO4/GCE also gives excellent selectivity, stability, repeatability, and reproducibility. We achieved excellent recovery results in real photographic solution and river water samples analysis with great accuracy. This work offers a novel insight into the growth of the carbon-based niobate family with electrochemical sensor applications.

Synthesis of hierarchically porous 3D polymeric carbon superstructures with nitrogen-doping by self-transformation: a robust electrocatalyst for the detection of herbicide bentazone.

Bentazone (BEZ) is one of the utmost selective problematic contact-past herbicide with high toxicity for humans owing to feasible contamination of surface and ground water. In this work, an electrochemical sensor has been developed for the sensitive detection of BEZ, based on hierarchically porous three-dimensional (3D) carbon superstructures (CS)-modified electrodes. The CSs (namely, CSHEX, CSPY, CSACN, and CSNOS) were prepared by the pyrolysis process from organic porous polyacrylonitrile (PAN) superstructure particles (namely, PANHEX, PANPY, PANACN, and PANNOS) obtained by free radical polymerization method using different solvents (hexane, pyridine, acetonitrile, and also no solvent). The assembly with the working electrode of CSs causes the electrocatalytic BEZ oxidation by rapid electron transfer compared to the PAN superstructures and bare electrodes. Intriguingly, compared to all electrodes, CSHEX-modified electrode showed the superior electrochemical detection of BEZ at a working potential of 0.99 V (vs. Ag/AgCl), very low detection limit (0.002 µM), wide dynamic linear range (0.03 to 200 µM), high sensitivity (9.95 µA µM-1 cm-2), and excellent reliability. The advanced sensors displayed an intensification of oxidation peak current of BEZ with high selectivity, remarkable sensitivity, and reproducibility for BEZ detection and received satisfactory outcomes designating the application of sensors for the determination of BEZ in river water samples.

Glutathione and cystamine functionalized MoS2core-shell nanoparticles for enhanced electrochemical detection of doxorubicin.

Two-dimensional (2D) MoS2core-shell nanoparticles were synthesized using an eco-friendly surface functionalization-agent with L-glutathione and cystamine (L-GSH-MoS2-CYS) using ultrasonic frequency of 20-25 kHz. The novel modified electrode was evaluated for the electrochemical detection of doxorubicin (DOX), through cyclic and differential pulse voltammetric techniques. The electro-catalytic oxidation currents of DOX exhibited a linear relationship in the concentration ranges 0.1-78.3 and 98.3-1218 µM, with a detection limit of 31 nM. A sensitivity of 0.017µA µM-1 cm-2 was acquired at 0.48 V. The fabricated L-GSH-MoS2-CYS modified electrode showed excellent precision, selectivity, repeatability, and reproducibility during the determination of DOX levels in blood serum samples. Thus, the fabricated L-GSH-MoS2-CYS/GCE modified electrode has potential for clinical applications for optimization of chemotherapeutic drugs owing to its selectivity, ease of preparation, and long-term stability. Graphical abstract.

Photo-Responsive Supramolecular Micelles for Controlled Drug Release and Improved Chemotherapy.

Development of stimuli-responsive supramolecular micelles that enable high levels of well-controlled drug release in cancer cells remains a grand challenge. Here, we encapsulated the antitumor drug doxorubicin (DOX) and pro-photosensitizer 5-aminolevulinic acid (5-ALA) within adenine-functionalized supramolecular micelles (A-PPG), in order to achieve effective drug delivery combined with photo-chemotherapy. The resulting DOX/5-ALA-loaded micelles exhibited excellent light and pH-responsive behavior in aqueous solution and high drug-entrapment stability in serum-rich media. A short duration (1-2 min) of laser irradiation with visible light induced the dissociation of the DOX/5-ALA complexes within the micelles, which disrupted micellular stability and resulted in rapid, immediate release of the physically entrapped drug from the micelles. In addition, in vitro assays of cellular reactive oxygen species generation and cellular internalization confirmed the drug-loaded micelles exhibited significantly enhanced cellular uptake after visible light irradiation, and that the light-triggered disassembly of micellar structures rapidly increased the production of reactive oxygen species within the cells. Importantly, flow cytometric analysis demonstrated that laser irradiation of cancer cells incubated with DOX/5-ALA-loaded A-PPG micelles effectively induced apoptotic cell death via endocytosis. Thus, this newly developed supramolecular system may offer a potential route towards improving the efficacy of synergistic chemotherapeutic approaches for cancer.

Synthesis of "Dahlia-Like" Hydrophilic Fluorescent Carbon Nanohorn as a Bio-Imaging PROBE.

Carbon nanohorns (CNH) were synthesized by a simple conventional hydrothermal method in this study. The CNHs were prepared by the chemical oxidation from the carbonation of Nafion (catalyst) with heparin (carbon resource). The formation of CNH involved two major steps, as described followed. First, the formation of carbon nanorice (CNR) was achieved by carbonation and self-assembly of heparin inside the Nafion structure. Second, the further oxidation of CNR resulted the heterogeneous and porous micelle domains showed at the outer layer of the CNR particles. These porous domains exhibited hydrophobic carbon and resulted self-assembly of the CNR to form the structure of CNHs. The resulting CNHs aggregated into a "dahlia-like" morphology with fluorescence in a diameter of 50-200 nm. The "dahlia-like" CNH showed better fluorescence (450nm) than CNR particles because of the presence of more structural defect. These findings suggest that the hydrophilic fluorescent carbon nanohorns (HFCNHs) synthesized in this study have the potential to be used for in vitro bio-imaging.

Synthesis and Characterization of Dual-Sensitive Fluorescent Nanogels for Enhancing Drug Delivery and Tracking Intracellular Drug Delivery.

Here, dual-sensitive fluorescent branched alginate-polyethyleneimine copolymer (bAPSC) nanogels were synthesized from thiolated alginate and stearoyl-derivatized branched polyethyleneimine. The formation of bAPSC conjugates was confirmed through proton nuclear magnetic resonance and Fourier transform infrared spectroscopy, whereas dynamic light scattering was used to measure the particle size and ζ potential of the nanogels. The fluorescent properties of the nanogels were confirmed through fluorescent spectroscopy and microscopy. In addition to the excitation-dependent fluorescence behavior, the fluorescence emission intensity of bAPSC was altered by both pH and γ-irradiation. This intensity was higher at a lower pH than at a higher pH, and it slightly decreased after γ-irradiation. The drug loading and encapsulation efficiency of bAPSC were 25.9% and 11.2%, respectively. An in vitro drug release study revealed that the synthesized nanogels release their doxorubicin (Dox) contents in a time-dependent manner, and the drug release was higher after 96 h of incubation. Approximately 43.74% and 88.36% of Dox was released after 96 h of incubation at pH 5.5 in the absence and presence of glutathione (GSH), respectively. However, relatively lower drug release, approximately 21.6% and 16%, was observed in the presence and absence of GSH at pH 7.4, respectively. Fluorescence microscopy confirmed that Dox-loaded bAPSC nanogels were internalized by HeLa cells, and drug distribution was easily tracked using fluorescent materials without additional probing agents. Moreover, cellular cytotoxicity and hemolysis results revealed less cytotoxicity and hemocompatibility of the synthesized nanogels, confirming that they are the most favorable alternative drug carriers for drug delivery systems.

Drug Carrier for Photodynamic Cancer Therapy.

Photodynamic therapy (PDT) is a non-invasive combinatorial therapeutic modality using light, photosensitizer (PS), and oxygen used for the treatment of cancer and other diseases. When PSs in cells are exposed to specific wavelengths of light, they are transformed from the singlet ground state (S0) to an excited singlet state (S1-Sn), followed by intersystem crossing to an excited triplet state (T1). The energy transferred from T1 to biological substrates and molecular oxygen, via type I and II reactions, generates reactive oxygen species, (¹O2, H2O2, O2*, HO*), which causes cellular damage that leads to tumor cell death through necrosis or apoptosis. The solubility, selectivity, and targeting of photosensitizers are important factors that must be considered in PDT. Nano-formulating PSs with organic and inorganic nanoparticles poses as potential strategy to satisfy the requirements of an ideal PDT system. In this review, we summarize several organic and inorganic PS carriers that have been studied to enhance the efficacy of photodynamic therapy against cancer.

Doxorubicin-loaded Polymeric Biotin-PEG-SeSe-PBLA Micelles with surface Binding of Biotin-Mediated Cancer Cell Targeting and Redox-Responsive Drug release for enhanced anticancer efficacy.

Biotin receptors are overexpressed in various cancer cell types, essential in tumor development, metabolism, and metastasis. Chemotherapeutic agents may be more effective and have fewer adverse effects if they specifically target the biotin receptors on cancer cells. Polymeric micelles (PMs) with nanoscale size via the EPR effect to accumulate near tumor tissue. We utilized the solvent exchange technique to crate polymeric Biotin-PEG-SeSe-PBLA micelles. This underwent self-assembly to create uniformly dispersed PMs with a hydrodynamic diameter of 81.54 ± 0.23 nm. The resulting PMs characterized by 1HNMR, 13CNMR, FTIR, and Raman spectroscopy. PMs exhibited a high efficacy of Doxorubicin encapsulation (EE) and loading content (DLC), with values of 5.93 wt% and 74.32 %, respectively. DOX@Biotin-PEG-SeSe-PBLA micelles showed optimal DOX release, around 89 % and 74 % in 10 mM glutathione and 0.1 % H2O2, respectively, within 72 hours, in the simulated cancer redox pool. Fascinatingly, the blank Biotin-PEG-SeSe-PBLA micelles did not affect the HaCaT or HeLa cell lines; approximately 85 % of the cells were metabolically active. Contrarily, at a 5 µg/ml concentration, DOX@Biotin-PEG-SeSe-PBLA specifically inhibited the proliferation of roughly 76 % of HeLa cells and 11 % of HaCaT cells. The fluorescence microscopy results demonstrated that biotin-decorated micelles were more successfully internalized by HeLa cells, which overexpress the biotin receptor, than by non-targeted micelles in vitro. In summary, the diselenide-linked Biotin-PEGSeSe-PBLA formed smart PMs that could offer DOX specific to cancer cells with precision and are physiologically durable.

Mucin-mediated mucosal retention via end-terminal modified Pluronic F127-based hydrogel to increase drug accumulation in the lungs.

Noninvasive lung drug delivery is critical for treating respiratory diseases. Pluronic-based copolymers have been used as multifunctional materials for medical and biological applications. However, the Pluronic F127-based hydrogel is rapidly degraded, adversely affecting the mechanical stability for prolonged drug release. Therefore, this study designed two thermosensitive copolymers by modifying the Pluronic F127 terminal groups with carboxyl (ADF127) or amine groups (EDF127) to improve the viscosity and storage modulus of drug formulations. ß-alanine and ethylenediamine were conjugated at the terminal of Pluronic F127 using a two-step acetylation process, and the final copolymers were characterized using 1H nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectra. According to the 1H NMR spectra, Pluronic F127 was functionalized to form ADF127 and EDF127 with 85 % and 71 % functionalization degrees, respectively. Rheological studies revealed that the ADF127 (15 wt%) and EDF127 (15 wt%) viscosities increased from 1480 Pa.s (Pluronic F127) to 1700 Pa.s and 1800 Pa.s, respectively. Furthermore, the elastic modulus of ADF127 and EDF127 increased, compared with that of native Pluronic F127 with the addition of 5 % mucin, particularly for ADF127, thereby signifying the stronger adhesive nature of ADF127 and EDF127 with mucin. Additionally, ADF127 and EDF127 exhibited a decreased gelation temperature, decreasing from 33 °C (Pluronic F127 at 15 wt%) to 24 °C. Notably, the in vitro ADF127 and EDF127 drug release was prolonged (95 %; 48 h) by the hydrogel encapsulation of the liposome-Bdph combined with mucin, and the intermolecular hydrogen bonding between the mucin and the hydrogel increased the retention time and stiffness of the hydrogels. Furthermore, ADF127 and EDF127 incubated with NIH-3T3 cells exhibited biocompatibility within 2 mg/mL, compared with Pluronic F127. The nasal administration method was used to examine the biodistribution of the modified hydrogel carrying liposomes or exosomes with fluorescence using the IVIS system. Drug accumulation in the lungs decreased in the following order: ADF127 > EDF127 > liposomes or exosomes alone. These results indicated that the carboxyl group-modified Pluronic F127 enabled well-distributed drug accumulation in the lungs, which is beneficial for intranasal administration routes in treating diseases such as lung fibrosis.

Thermosensitive hydrogel from oligopeptide-containing amphiphilic block copolymer: effect of peptide functional group on self-assembly and gelation behavior.

We reveal that a slight change in the functional group of the oligopeptide block incorporated into the poloxamer led to drastically different hierarchical assembly behavior and rheological properties in aqueous media. An oligo(L-Ala-co-L-Phe-co-ß-benzyl L-Asp)-poloxamer-oligo(ß-benzyl-L-Asp-co-L-Phe-co-L-Ala) block copolymer (OAF-(OAsp(Bzyl))-PLX-(OAsp(Bzyl))-OAF, denoted as polymer 1), which possessed benzyl group on the aspartate moiety of the peptide block, was synthesized through ring-opening polymerization. The benzyl group on aspartate was then converted to carboxylic acid to yield oligo(L-Ala-co-L-Phe-co-L-Asp)-poloxamer-oligo(L-Asp-co-L-Phe-co-L-Ala) (OAF-(OAsp)-PLX-(OAsp)-OAF, denoted as polymer 2). Characterization of the peptide secondary structure in aqueous media by circular dichroism revealed that the oligopeptide block in polymer 1 exhibited mainly an α-helix conformation, whereas that in polymer 2 adopted predominantly a ß-sheet conformation at room temperature. The segmental dynamics of the PEG in polymer 1 remained essentially unperturbed upon heating from 10 to 50 °C; by contrast, the PEG segmental motion in polymer 2 became more constrained above ca. 35 °C, indicating an obvious change in the chemical environment of the block chains. Meanwhile, the storage modulus of the polymer 2 solution underwent an abrupt increase across this temperature, and the solution turned into a gel. Wet-cell TEM observation revealed that polymer 1 self-organized to form microgel particles of several hundred nanometers in size. The microgel particle was retained as the characteristic morphological entity such that the PEG chains did not experience a significant change of their chemical environment upon heating. The hydrogel formed by polymer 2 was found to contain networks of nanofibrils, suggesting that the hydrogen bonding between the carboxylic acid groups led to an extensive stacking of the ß sheets along the fibril axis at elevated temperature. The in vitro cytotoxicity of the polymer 2 aqueous solution was found to be low in human retinal pigment epithelial cells. The low cytotoxicity coupled with the sol-gel transition makes the corresponding hydrogel a good candidate for biomedical applications.

Plasmonic nanoparticle-based surface-enhanced Raman spectroscopy-guided photothermal therapy: emerging cancer theranostics.

Optical imaging modalities have emerged as a keystone in oncological research, capable of providing molecular and cellular information on cancer with the advantage of being minimally invasive toward healthy tissues. Photothermal therapy (PTT) has shown great potential, with the exceptional advantages of high specificity and noninvasiveness. Combining surface-enhanced Raman spectroscopy (SERS)-based optical imaging with PTT has shown tremendous potential in cancer theranostics (therapeutics + diagnosis). This comprehensive review article provides up-to-date information by exploring recent works focused mainly on the development of plasmonic nanoparticles for medical applications using SERS-guided PTT, including the fundamental principles behind SERS and the plasmon heating effect for PTT.

Hofmeister effect-based soaking strategy for gelatin hydrogels with adjustable gelation temperature, mechanical properties, and ionic conductivity.

As a natural polymer with good biocompatibility, gelatin hydrogel has been widely used in the field of biomedical science for a long time. However, the lack of suitable gelation temperature and mechanical properties often limit the clinical applicability in diverse and complex environments. Here, we proposed a strategy based on the Hofmeister effect that gelatin hydrogels were soaked in the appropriate concentration of sodium sulfate solution, and the change in molecular chain interactions mainly guided by kosmotropic ions resulted in a comprehensive adjustment of multiple properties. A series of gelatin hydrogels treated with different concentrations of the salt solution gave rise to microstructural changes, which brought a decrease in the number and size of pores, a wide range of gelation temperature from 32 °C to 46 °C, a stress enhancement of about 40 times stronger to 0.8345 MPa, a strain increase of about 7 times higher to 238.05 %, and a certain degree of electrical conductivity to be utilized for versatile applications. In this regard, for example, we prepared microneedles and obtained a remarkable compression (punctuation) strength of 0.661 N/needle, which was 55 times greater than those of untreated ones. Overall, by integrating various characterizations and suggesting the corresponding mechanism behind the phenomenon, this method provides a simpler and more convenient performance control procedure. This allowed us to easily modulate the properties of the hydrogel as per the intended purpose, revealing its vast potential applications such as smart sensors, electronic skin, and drug delivery.

Fabrication and characterization of hybrid eco-friendly high methoxyl pectin/gelatin/TiO2/curcumin (PGTC) nanocomposite biofilms for salmon fillet packaging.

Hybrid eco-friendly nanocomposite films were fabricated by blending high-methoxyl pectin, gelatin, TiO2, and curcumin through the solution casting method. Various concentrations (0-5 wt%) of TiO2 nanoparticles (TNPs) and curcumin as an organic filler were added to the blend solutions. A high TNP concentration affected the surface morphology, roughness, and compactness of the films. Additionally, 3D mapping revealed the nanoparticle distribution in the film layers. Moisture content, water solubility, and light transmittance reduced dramatically with increasing TNP content, in accordance with the water vapor and oxygen permeabilities. X-ray diffraction revealed that the films were semicrystalline nanocomposites, and the thermal properties of the films increased when 5 wt% of TNPs was incorporated into the blend solution. Fourier-transform infrared and Raman analyses revealed interactions among biopolymers, nanoparticles, and organic fillers through hydrogen bonding. The shelf life of fresh salmon fillets was prolonged to six days for all groups, revealed by total viable counts and psychrotrophic bacteria counts, and the pH of the salmon fillets could be extended until the sixth day for all groups. Biodegradation assays demonstrated a significant weight loss in the nanocomposite films. Therefore, a nanocomposite film with 5 wt% TNPs could potentially be cytotoxic to NIH 3T3 cells.

Multifunctional thermosensitive hydrogel based on alginate and P(NIPAM-co-HEMIN) composites for accelerated diabetic wound healing.

Non-healing wounds in patients with diabetes are a concerning issue associated with amputation and a high mortality rate. These wounds are exacerbated by oxidative stress and microbial infections resulting from hyperglycemia. Therefore, advanced materials for repairing wound beds must be identified urgently. This paper introduces a topically applicable composite hydrogel with thermosensitive properties and presents the antibacterial and antioxidant activities in mice with diabetes-induced wounds. This composite is developed by combining poly N-isopropyl acrylamide (NIPAM)-copolymerized HEMIN (NIPAM-co-HEMIN) and amine-modified alginate (ALG-EDA) biomaterials, with Ag nanoparticles (AgNPs) incorporated into the system as an antibacterial agent. Results of antibacterial tests show that the p(NIPAM-co-HEMIN)/ALG-EDA/AgNP composite system is effective against E. coli and S. aureus. Additionally, the AgNP composite exhibits low cellular toxicity in NIH3T3 and CT-2A cell lines. The wounds in diabetic mice treated with the composite system healed in <12 days, and the composite system accelerated the healing process by increasing collagen synthesis. In conclusion, the biocomposite reported herein is highly promising for repairing diabetic skin wounds and treating infections caused by bacterial microbes.