Cross-linking Ratio Research Articles

Formulation, Characterization, Anti-Inflammatory and Cytotoxicity Study of Sesamol-Laden Nanosponges.

Sesamol (SES) possesses remarkable chemotherapeutic activity, owing to its anti-inflammatory and antioxidant potential. However, the activity of SES is mainly hampered by its poor physicochemical properties and stability issues. Hence, to improve the efficacy of this natural anti-inflammatory and cytotoxic agent, it was loaded into β-cyclodextrin nanosponges (NS) prepared using different molar ratios of polymer and crosslinker (diphenyl carbonate). The particle size of SES-laden NS (SES-NS) was shown to be in the nano range (200 to 500 nm), with a low polydispersity index, an adequate charge (-17 to -26 mV), and a high payload. Field emission scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy were used to characterize the bioactive-loaded selected batch (SES-NS6). This batch of nanoformulations showed improved solubilization efficacy (701.88 µg/mL) in comparison to bare SES (244.36 µg/mL), polymer (β-CD) (261.43 µg/mL), and other fabricated batches. The drug release data displayed the controlled release behavior of SES from NS. The findings of the egg albumin denaturation assay revealed the enhanced anti-inflammatory potential of SES-NS as compared to bare SES. Further, the cytotoxicity assay showed that SES-NS was more effective against B16F12 melanoma cell lines than the bioactive alone. The findings of this assay demonstrated a reduction in the IC50 values of SES-NS (67.38 μg/mL) in comparison to SES (106 μg/mL). The present investigation demonstrated the in vitro controlled release pattern and the enhanced anti-inflammatory and cytotoxic activity of SES-NS, suggesting its potential as a promising drug delivery carrier for topical delivery.

Monitoring of silica colloidal crystal-embedded chitosan hydrogel films swelling and its drug release application

The hydrogels, because of their swelling properties in response to the environmental stimulus, are being widely considered for the design of controlled drug release systems. To meet the need for developing effective drug delivery methods, we developed special silica colloidal crystal (SCC)-embedded chitosan hydrogel films. The SCC films served as an interference substrate and drug storage layer, while the chitosan hydrogel served as a cover to regulate the drug release. The optical interferometry was performed to dynamically monitor the volume phase transition of chitosan hydrogel response to pH stimulation. Furthermore, the effects of crosslinking ratio and hydrogel thickness on the swelling properties of chitosan hydrogel were also evaluated. More importantly, the pH-responsive swelling of chitosan hydrogel was used to slowly release indomethacin. This system may provide support for drug delivery studies, therefore further expected to apply in the enhancement of the treatment efficiency of new drug therapies.

Synthesis and characterization of gelatin/lignin hydrogels as quick release drug carriers for Ribavirin

In this study, hydrogels based on gelatin and lignin were fabricated as efficient drug carriers for Ribavirin. The obtained hydrogels were characterized by scanning electron microscopy (SEM), ATR-FTIR spectroscopy, differential scanning calorimetry (DSC), mechanical compression and rheometry. Results showed that the pore structure, viscoelastic behavior and swelling ability significantly influenced by varying lignin content and crosslinker ratio. By increasing the crosslinker N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) content, the pore size became smaller, while increasing the lignin content resulted in larger pores. In addition, all hydrogels show strong shear thinning behavior. Ribavirin was used as a drug model, and its release rate was enhanced by increasing lignin content in the binary hydrogel structure. A higher Ribavirin cumulative release was observed for gelatin/lignin with higher lignin content (3 %) hydrogel. These findings emphasize the chemical composition on the structure and the release behavior of lignin-containing hydrogels.

Application of molecularly imprinted electrochemical sensor for trace analysis of Metribuzin herbicide in food samples

Metribuzin (MTZ) is an important herbicide widely used in fields and represents a big threat to the environment and health. Herein, an electrochemical sensor was designed for its detection in commercial product (Egyscor® 70%), spiked tomatoes and potatoes samples with recovery values ranging from 97.12 to 103.41%. Bulk-polymerized MTZ molecularly imprinted polymer (MIP) was developed, using itaconic acid (functional monomer), ethylene glycol dimethacrylate (cross-linker) at an optimum molar ratio 1:5:30, respectively. Differential pulse voltammetry was used to examine the optimization variables of the MIP based sensor such as the variation of (template: monomer: cross-linker) ratio, accumulation time, multi walled carbon nanotubes amount, pH and scan rate, while cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the sensor. The sensor showed selective adsorption ability and a good linearity over the concentration range of 0.2 ng/mL to 21.429 µg/mL, with LOD and LOQ of 0.1 pg/mL and 0.3 pg/mL, respectively.

Synthesis, Characterization, and Swelling Properties of a New Highly Absorbent Hydrogel Based on Carboxymethyl Guar Gum Reinforced with Bentonite and Silica Particles for Disposable Hygiene Products.

Superabsorbent polymers derived from petroleum have been widely used as the primary component of high-water-absorption disposable sanitary products. However, environmental concerns as well as unstable market prices influence the quality of disposable hygiene products. The development of superabsorbent polymers from natural, non-petroleum-derived materials has become more predominant. In the present study, two borax-cross-linked carboxymethyl guar-based superabsorbents with bentonite (CMG-Bt) and fumed silica particle reinforcement (CMG-Bt-Si) were synthesized. The materials have been fully characterized by various techniques. The swelling behavior was studied through free swelling capacity (FSC) and centrifuge retention capacity (CRC). The swelling kinetics and urea absorption capacity were further analyzed. The effects of the cross-linking ratio, mineral clay, silica particles, and pH of the liquids on the swelling properties of the superabsorbents have been studied. The incorporation of silica particles demonstrated a positive effect on water uptake reaching 78.63 and 41.09 g/g of FSC and CRC, respectively, at an optimum pH of 6.8. The optimum swelling kinetics were attributed to CMG-Bt-Si of 5 wt % silica particle content, indicating a velocity parameter (ζ) of 41 s in saline solution. Finally, the highest swelling values were obtained at 10, 10, and 5 wt % for the cross-linking ratio, bentonite content, and silica particle content, respectively; in addition, the absorption of urea by the CMG-Bt-Si material was also confirmed.

Thermally remendable, weldable, and recyclable epoxy network crosslinked with reversible Diels-alder bonds

The development of epoxy resins through Diels-Alder crosslinking is challenging: the synthesis is complex, and the mechanical properties are hindered by the brittleness of these bonds. In this work, an epoxy/amine resin with different Diels-Alder crosslinking ratios is manufactured, achieving a simplified route that enhances both sustainability and industrial transferability. The curing temperatures are carefully studied, defining a two-step method (100 °C, 6 h + 60 °C, 12 h) that generates the thermo-reversible resins dispending the use of solvents or intermediate oligomers synthesis. Besides NMR, FTIR, and DSC characterization, the influence of Diels-Alder bonds on mechanical properties is analyzed. The addition of Diels-Alder crosslinking up to a 0.6 ratio of the stoichiometry provides an epoxy with an optimal compromise between recyclability and mechanical properties. Using this ratio, the effect of Diels-Alder crosslinking and disengagement is analyzed through DMTA and microhardness, demonstrating the network reversibility and the feasibility of this techniques to monitor its evolution. • Diels-Alder resins are manufactured without solvents or intermediate prepolymers. • Diels-Alder crosslinked networks show repeatable thermal reversibility. • Diels-Alder reversibility is measured through DMTA and microhardness for first time. • Medium Diels-Alder contents exhibit both reversibility and mechanical properties. • The synthetized resins show self-healing, thermal forming, and recycling capabilities.

An investigation on nematic-isotropic phase transition, viscosity and diffusion coefficient of liquid crystalline elastomers at different temperatures using molecular dynamics simulation

The most considerable feature of liquid crystalline elastomers (LCEs) is nematic-isotropic phase transition which has severe effects on their properties such as crystallinity, viscosity, and diffusion coefficient. The aim of this work is to investigate the phase transition temperature of LCEs based on 4-bis-[4-(3-acryloyloxypropypropyloxy) benzoyloxy]-2-methylbenzene as monomer using a coarse-grained molecular dynamics simulation. In this regard, by assessing the crystallinity as a function of temperature, the most suitable ratio of crosslinker to other components including monomer and flexible spacer is 50 %; thereby, obtaining the highest nematic phase percentage around 60 %. At this condition, the nematic-isotropic phase transition temperature is predicted 360 K. Besides the crystallinity studies, the viscosity and diffusion coefficient against temperature show that the nematic-isotropic phase transition temperature has significant influence on the variations of structural and dynamic properties of LCEs.

Sustainable lignin precursors for tailored porous carbon-based supercapacitor electrodes

Sustainable materials are attracting a lot of attention since they will be critical in the creation of the next generation of products and devices. In this study, hydrogels were effectively synthesized utilizing lignin, a non-valorised biopolymer from the paper industry. This study proposes a method based on utilizing lignin to create highly swollen hydrogels using poly(ethylene) glycol diglycidyl ether (PEGDGE) as a crosslinking agent. The influence of different crosslinker ratios on the structural and chemical properties of the resultant hydrogels was investigated. Pore size was observed to be lowered when the amount of crosslinker was increased. The inclusion of additional hydrophilic groups in the hydrogel network decreased the swelling capacity of the hydrogels as the crosslinking density increases. These precursor materials were carbonised and electrochemically tested for application as electrodes for supercapacitors with capacitance characterized as a function of crosslinker ratio.

Novel biodegradable molecularly imprinted polymer nanoparticles for drug delivery of methotrexate anti-cancer; synthesis, characterization and cellular studies.

Recently biodegradable nanoparticles are the center of attention for the development of drug delivery systems. Molecularly imprinted polymer (MIP) is an interesting candidate for designing drug nano-carriers. MIP-based nanoparticles could be used for cancer treatment and exhibited the potential to fill gaps regarding to ligand-based nanomaterials. Also, the presence of a cross-linker can play an essential role in nanoparticle stability and physicochemical properties of nanoparticles after synthesis. In this research, a biodegradable drug delivery system based on MIP nanoparticles was prepared using a biodegradable cross-linker (dimethacryloyl hydroxylamine, DMHA) for methotrexate (MTX). A hydrolysable functional group CO-O-NH-CO was added to the crosslinking agent to increase the final biodegradability of the polymer. Firstly, a biodegradable cross-linker was synthesized. Then, the non-imprinted polymers were prepared through mini-emulsion polymerization in the absence of a template; and efficient particle size distribution was determined. Finally, methotrexate was placed in imprinted polymers to achieve the desired MIP. Different types of MIPs were synthesized using different molar ratios of template, cross-linker, and functional monomer, and the optimal molar ratio was obtained at 1:4:20, respectively. HNMR successfully confirmed the chemical structure of the cross-linker. According to SEM images, nanoparticles had a spherical shape with a smooth surface. The imprinted nanoparticles showed a narrow size distribution with an average of 120nm at a high ratio of cross-linker. The drug loading and entrapment efficiency were 6.4% and 92%, respectively. The biodegradability studies indicated that the nanoparticles prepared by DMHA had a more degradability rate than ethylene glycol dimethacrylate as a conventional cross-linker. Also, the polymer degradation rate was higher in alkaline environments. Release studies in physiological and alkaline buffer showed an initial burst release of a quarter of loaded MTX during the day and a 70% release during a week. The Korsmeyer-Peppas model described the release pattern. The cytotoxicity of MTX loaded in nanoparticles was studied on the MCF-7 cell line, and the IC50 was 3.54μg/ml. It was demonstrated that nanoparticles prepared by DMHA have the potential to be used as biodegradable drug carriers for anticancer delivery. Synthesis schema of molecular imprinting of methotrexate in biodegradable polymer based on dimethacryloyl hydroxylamine cross-linker, for use as nanocarrier anticancer delivery to breast tumor.

Synthesis of cross-linked carboxymethyl cellulose and poly (2-acrylamido-2-methylpropane sulfonic acid) hydrogel for sustained drug release optimized by Box-Behnken Design

This research aims to fabricate and characterize chemically crosslinked CMC/PVP-co-poly (AMPS) based hydrogel for the sustained release of model drug metoprolol tartrate through the free radical polymerization technique. Box-Behnken Design was used to optimize CMC/PVP-co-poly (AMPS) hydrogel by varying the content of reactants such as; polymers (CMC and PVP), monomer (AMPS), and crosslinker (EGDMA). Carboxymethyl cellulose (CMC) was crosslinked chemically with AMPS with a constant ratio of PVP by the ethylene glycol dimethacrylate as the crosslinker in the presence of sodium hydrogen sulfite (SHS)/ammonium peroxodisulfate (APS) as initiators. After developing CMC-based hydrogels using different polymers, monomer, and crosslinker concentrations, this study encompassed dynamic swelling, sol–gel fraction, drug release and chemical characterizations such as FTIR, XRD, TGA, DSC, and SEM. In vitro drug release and swelling were performed at 1.2 and 6.8 pH to determine the sustained release pattern and pH-responsive behavior. These parameters depended on the crosslinker, polymer, and monomer ratios used in the formulation development. XRD, SEM, and FTIR showed the successful grafting of constituents resulting in the formation of a stable hydrogel. DSC and TGA confirmed the thermodynamic stability of the hydrogel. Hydrogel swelling was increased with an increase in the ratio of monomer; however, an increase in the ratio of polymer and crosslinker decreased the hydrogel swelling. In vitro gel fraction and drug release also depended on polymer, monomer, and crosslinker ratios. The fabricated CMC/PVP-co-poly (AMPS) hydrogels constituted a potential system for sustained drug delivery.

Shaping polyelectrolyte composites for heavy metals adsorption from wastewater: Experimental assessment and equilibrium studies

Design of core/shell composite microparticles for loading/release of organic/inorganic pollutants is of great interest in wastewater treatment. As compared to the classic layer-by-layer strategy, the new approach presented in this study introduced higher organic shell amounts in one-pot deposition step, with less material and energy consumption and lack of toxic by-products formation. Herein, one weak polycation (polyethyleneimine) and two weak polyanions were directly deposited onto silica surface through precipitation of an in-situ formed interpolyelectrolyte coacervate, followed by selective crosslinking with glutaraldehyde and extraction of polyanion chains, confirmed by electrokinetic measurements and FTIR spectra of composites. Twelve composite sorbents were synthesized and tested for adsorption of cadmium, as model heavy metal ion. It was demonstrated that the high sorption occurred onto four newly synthesized composites which is correlated to the deposited shell amount, dependent on the deposition method, polyanion nature and crosslinking ratio. The Cd2+ sorbed amount increased with the polyelectrolyte deposited amount and with the accessibility toward active sorption site, less cross-linked composite shells sorbing higher amounts as compared to strong cross-linked shells, the molar ratio [active site]:[Cd2+] ranging from 16:1 to 26:1. The best fitting of four isotherm (Langmuir, Freundlich, Sips and Toth) and four kinetics (pseudo-first order, pseudo-second order, modified Freundlich and Elovich) models was assessed by the sum of normalized errors, based on different nonlinear regression error functions, and by the Hannah-Quinn information criterion. In general, the best agreement with the experimental data was found for Toth isotherm and the pseudo-second order kinetic model. Efficient regeneration of the sorbents was possible at least three times. The competitive effect of Pb2+ and Ni2+ ions was also studied in simulated and real systems. Silica composite sorbents with polyethyleneimine chains as major component of the shell could be very promising in wastewater treatment processes.

Highly Improved Chiral-Selective Resolution in Pillar[5]arene-Functionalized Molecularly Imprinted Membranes

It is a challenging task to achieve the effective separation of chiral compounds under simple and rapid conditions. In order to solve this problem, this study used the molecularly imprinted membrane (MIM) technology developed on the basis of biological semi-permeable membranes, using S-triadimefon as the template molecule, and successfully prepared MIMs by photo-initiated polymerization. By adding macrocyclic molecular 1,4-bis(allyloxy)pillar[5]arene as a functional monomers, the effectiveness of the chiral recognition sites of the target molecules is improved, thereby improving the chiral selectivity of the MIM and optimizing the molar ratio of template molecules, monomers, and cross-linkers. On this basis, the separation effect of non-MIM (NIM), single-monomer MIM (MIM-I), and two-monomer MIM (MIM-II) on triadimefon enantiomers was investigated. It was found that the enantiomer excess (e. e.) % value of MIM-I is larger than that of NIM, but the value of MIM-I is still very low. When pillar[5]arene, a macrocyclic molecule was added as the second monomer, its e. e. % increased from 27.4 to 84.8%.

Degradable and Non-Degradable Chondroitin Sulfate Particles with the Controlled Antibiotic Release for Bacterial Infections.

Non-degradable, slightly degradable, and completely degradable micro/nanoparticles derived from chondroitin sulfate (CS) were synthesized through crosslinking reactions at 50%, 40%, and 20% mole ratios, respectively. The CS particles with a 20% crosslinking ratio show total degradation within 48 h, whereas 50% CS particles were highly stable for up to 240 h with only 7.0 ± 2.8% weight loss in physiological conditions (pH 7.4, 37 °C). Tobramycin and amikacin antibiotics were encapsulated into non-degradable CS particles with high loading at 250 g/mg for the treatment of corneal bacterial ulcers. The highest release capacity of 92 ± 2% was obtained for CS-Amikacin particles with sustainable and long-term release profiles. The antibacterial effects of CS particles loaded with 2.5 mg of antibiotic continued to render a prolonged release time of 240 h with 24 ± 2 mm inhibition zones against Pseudomonas aeruginosa. Furthermore, as a carrier, CS particles significantly improved the compatibility of the antibiotics even at high particle concentrations of 1000 g/mL with a minimum of 71 ± 7% fibroblast cell viability. In summary, the sustainable delivery of antibiotics and long-term treatment of bacterial keratitis were shown to be afforded by the design of tunable degradation ability of CS particles with improved biocompatibility for the encapsulated drugs.

Factors Affecting the Analytical Performance of Magnetic Molecularly Imprinted Polymers.

During the last few years, separation techniques using molecular imprinting polymers (MIPs) have been developed, making certain improvements using magnetic properties. Compared to MIP, Magnetic molecularly imprinted polymers (MMIPs) have high selectivity in sample pre-treatment and allow for fast and easy isolation of the target analyte. Its magnetic properties and good extraction performance depend on the MMIP synthesis step, which consists of 4 steps, namely magnetite manufacture, magnetic coating using modified components, polymerization and template desorption. This review discusses the factors that will affect the performance of MMIP as a selective sorbent at each stage. MMIP, using Fe3O4 as a magnetite core, showed strong superparamagnetism; it was prepared using the co-precipitation method using FeCl3·6H2O and FeCl2·H2O to obtain high magnetic properties, using NH4OH solution added for higher crystallinity. In magnetite synthesis, the use of a higher temperature and reaction time will result in a larger nanoparticle size and high magnetization saturation, while a higher pH value will result in a smaller particle size. In the modification step, the use of high amounts of oleic acid results in smaller nanoparticles; furthermore, determining the correct molar ratio between FeCl3 and the shielding agent will also result in smaller particles. The next factor is that the proper ratio of functional monomer, cross-linker and solvent will improve printing efficiency. Thus, it will produce MMIP with high selectivity in sample pre-treatment.

Transmission of sodium chloride in PDMS membrane during Pervaporation based on polymer relaxation

Polydimethylsiloxane (PDMS) composite membrane is used for treating pharmaceutical wastewater containing NaCl and solvent. In this study, the influence of feed concentrations of NaCl and isobutanol, process temperature and membrane microstructures on salt rejection are evaluated. Microstructures of PDMS membrane before and after separation are characterized by nuclear magnetic resonance (NMR), energy dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Positron annihilation life-time spectroscopy (PALS). The PV results show that NaCl will not spontaneously enter PDMS membrane without isobutanol. However, while NaCl feed concentration is 13 wt%, salt rejection of PDMS membrane drops from 100% to 99.09% with increasing feed concentration of isobutanol (up to 7 wt%). On the contrary, a higher temperature increases salt rejection of PDMS membrane and NaCl permeation through PDMS membrane is not through a vapor permeate process. Due to the relaxation of PDMS polymer chain, when PDMS cross-linking ratio is 0.1, the salt rejection increases from 99.87% to 100% with its thickness increasing from 10 μm to 17.5 μm. While the cross-linking ratio rises to 0.2, the salt rejection is 100% with the PDMS layer thickness of 10 μm. The relationship between relaxation of polymer chains and transport of NaCl in PDMS membrane is an excellent guidance and will be beneficial for the treatment of saline organic wastewater.

Preparation of matrix-grafted graphene/poly(poly(ethylene glycol) methyl ether methacrylate) nanocomposite gel polymer electrolytes by reversible addition-fragmentation chain transfer polymerization for lithium ion batteries

A structural design and appropriate morphology of polymer-functionalized graphene oxide are occupied to optimize nanocomposite polymer electrolytes. The nanocomposite gel polymer electrolytes (GPEs) based on poly(poly (ethylene glycol) methyl ether methacrylate and RAFT agent-functionalized graphene oxide [P(PEGMA/GO-S-(thiobenzoyl)thioglycolic acid (STTA))] have been successfully prepared by in-situ polymerization method in different ratio of GO-STTA and crosslinking by poly(ethylene glycol) diallyl (PEGDA). The P(PEGMA/GO-STTA) GPE with 0.5 wt% of GO-STTA exhibited a high ionic conductivity of 5.5 mS cm−1 at room temperature, a superior lithium transfer number (t+) value of 0.61, and electrochemical window up 4.7 V. The GPE based P(PEGMA/GO-STTA0.5%) indicated 92% coulombic efficiency, the charge capacity value of 191.7 mAh g−1, and capacity retention was about 92% after 100 cycles at 0.1C. P(PEGMA/GO-STTA) GPEs showed great potential for lithium ion battery with high safety and long cycle life.

Superporous poly(β-Cyclodextrin) cryogels as promising materials for simultaneous delivery of both hydrophilic and hydrophobic drugs

Here, one step, simple preparation of superporous p(β-cyclodextrin) (p(β-CD)) cryogels in the presence of various ratios of crosslinker, divinyl sulfone (DVS) e.g., 100, 150, 200% mole with respect to the mole ratio of 6 hydroxyl groups on β-CD unit under cryogenic conditions were reported for the first time. The swelling properties, and hydrolytic degradation of p(β-CD) cryogels was directly related to the used crosslinker ratio. It was observed that the p(β-CD) cryogels showed higher swelling% in DMSO and DMF than in DI water. The prepared p(β-CD)-1 cryogel that was 100% crosslinked exhibited 14 ± 3.7%, 34 ± 4.8%, and 45 ± 6.2% weight losses within 20 days in pH 5.4, 7.4, and 9.0 buffer solutions, respectively. An acceptable hemolysis index of < 5% and a blood coagulation index, >89% were observed for the p(β-CD) cryogels at 1 mg/mL concentrations. Additionally, the potential useability of p(β-CD) cryogels as in vitro drug delivery systems for both hydrophilic vancomycin, and hydrophobic tetracycline as model drugs were individually illustrated at pH 7.4 in PBS. The cumulative drug release from p(β-CD) cryogels, in sustained release profiles with 76.7 ± 9.0 mg/g of vancomycin (89.9 ± 10.5% of the loaded amount) and 146.5 ± 19.4 mg/g tetracycline g (83.1 ± 6.3% of the loaded amount) were attained in 6 and 54 h, respectively at pH 7.4 in PBS. Most importantly, p(β-CD) cryogels exhibited simultaneous loading and releasing the ability for both hydrophilic vancomycin, and hydrophobic tetracycline drugs by concurrently releasing 37.0 ± 2.7 mg/g (23.4 ± 1.8% of the loaded amount), and 36.3 ± 1.3 mg/g (23.6 ± 0.8% of the loaded amount), respectively at pH 7.4 (PBS) in 10 h.

Simple synthesis of cellulose hydrogels based on the direct dissolution of cellulose in tetrabutylphosphonium hydroxide followed by crosslinking

AbstractCellulose‐based hydrogels are valuable sustainable materials with significant potential applications in biomedical fields such as cell therapy, hemostasis, wound healing, tissue transplantation, regeneration technology, and drug delivery carrier to cells. In contrast to previous studies, the standard synthesis procedure needs high temperature, low cellulose concentration, and many additives. Here cellulose‐based hydrogels with a high cellulose concentration are produced at room temperature. The one‐pot preparation of chemical hydrogels involves the dissolution of cellulose in tetrabutylphosphonium hydroxide followed by epichlorohydrin crosslinking. The effects of the wide range of microcrystalline cellulose concentrations and the crosslinker ratio on swelling properties and crosslink density under different conditions are investigated. The hydrogels are characterized using Fourier transform infrared spectroscopy and X‐ray diffraction. The morphology of hydrogels is examined through scanning electron microscope. The transparency of hydrogel is determined by ultraviolet–visible (UV–vis) spectrophotometer.

Effect of Exposure to Acidic Food Items on Dentin Characteristics: An ATR-FTIR Study

ATR-FTIR spectroscopy is a powerful technique for unraveling the fine features of dentin; however, its use in the analysis of eroded dentin remains underexplored. Herein, the impact of different acidic food products (a soft drink, vinegar, and yogurt) on dentin was investigated using ATR-FTIR spectroscopy. The durations of exposure were one, three, and seven days. One-way and two-way analyses of variance were employed to analyze differences in mean values among groups, followed by Dunnett’s and Tukey’s tests. After exposure, the mineral-to-matrix ratio in the three media was significantly lower than that in the control group. The carbonate-to-phosphate ratio and extent of crosslinking increased considerably after exposure to all media; however, the crystallinity index values decreased relative to that in the control group. These findings imply that ATR-FTIR may be an effective noninvasive technique for detecting erosion-induced changes in dentin, having a significant clinical impact on dental care.

Electrospun nanofibers based on carboxymethyl cellulose/polyvinyl alcohol as a potential antimicrobial wound dressing

In this work, citric acid-based quantum dots (CA-QDs) as a novel and safe crosslinked agent was applied in different feeding ratios (5–15 wt%) to synthesize carboxymethyl cellulose/polyvinyl alcohol (CMC/PVA) nanofibers (NFs) for the first time. Colistin (CL) as an antibacterial agent was also loaded (2 w/w%) during the synthesizing process of CMC/PVA electrospun NFs to trigger antimicrobial properties. The morphological, hydrophilic, and mechanical properties of the prepared NFs were fully investigated with different techniques. The electrospun NFs with crosslinking ratios of 10 wt% CA-QDs revealed appropriate mechanical properties. According to cell culture data, the prepared NFs demonstrated good cytocompatibility against HFF-1 cells (over 80% cell viability). Remarkably, CL-loaded NFs showed desired antibacterial efficacy against S. aureus, E. coli, K. pneumoniae, and P. aeruginosa with 1.0–1.4, 1.3–1.4, 0.8–1.0, and 1.3–1.5 cm inhibition zones, respectively. These outcomes suggested that the fabricated NFs can be useful as wound healing scaffolds.