Optimized design of quaternary amino-functionalized chitosan fibers for ultra-high diclofenac adsorption from wastewater.

The extraction of non-steroidal anti-inflammatory drugs (NSAIDs) from water bodies is imperative due to the potential harm to humans and the ecosystem caused by NSAID-contaminated water. Quaternary amino-functionalized epichlorohydrin cross-linked chitosan fibers (QECFs), an economical and eco-friendly adsorbent, were successfully prepared using a simple and gentle method for efficient diclofenac (DCF) adsorption. Additionally, the optimized factors for the preparation of QECFs included epichlorohydrin concentration, pH, temperature, and (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHTAC) concentration. QECFs demonstrated excellent adsorption performance for DCF across a broad pH range of 7-12. The calculated maximum adsorption capacity and the amount of adsorbed DCF per adsorption site were determined to be 987.5 ± 20.1 mg/g and 1.2 ± 0.2, respectively, according to the D-R and Hill isotherm models, at pH 7 within 180 min. This performance surpassed that of previously reported adsorbents. The regeneration of QECFs could be achieved using a 0.5 mol/L NaOH solution within 90 min, with QECFs retaining their original fiber form and experiencing only a 9.18% reduction in adsorption capacity after 5 cycles. The Fourier transform infrared spectrometer and X-ray photoelectron spectroscopy were used to study the characterization of QECFs, the preparation mechanism of QECFs, and the adsorption mechanism of DCF by QECFs. Quaternary ammonium groups (R4N+) were well developed in QECFs through the reaction between amino/hydroxyl groups on chitosan and CHTAC, and approximately 0.98 CHTAC molecule with 0.98 R4N+ group were immobilized on each chitosan monomer. Additionally, these R4N+ on QECFs played a crucial role in the removal of DCF.

Facile crosslinking methods for water-durable oven-dried cellulose nanofibril foams and their application as dye adsorbents.

The potential applications of cellulose nanofibril-based foam materials can be expanded by their enhanced water durability. This study proposes two crosslinking methods to improve the water durability of the oven-dried carboxymethylated cellulose nanofibril (CMCNF) foam. The first method involves the addition of a crosslinker, polyamideamine epichlorohydrin. The second method is the self-crosslinking of CMCNFs via heat treatment at 140 °C for less than an hour, which is a simple way to crosslink CMCNF-based materials. Both crosslinking methods resulted in excellent water durability and wet resilience of the foams, which also exhibited high water absorbency. Furthermore, neither method affected the structural nor mechanical properties of the oven-dried CMCNF foams. In particular, self-crosslinking by heat treatment proved to be as effective as using a crosslinking agent. Compared to the freeze-dried foam, the oven-dried foam exhibited slower methylene blue (MB) dye adsorption but a higher maximum adsorption capacity (238-250 mg/g), attributed to the closed pore structure and a larger specific surface area. In addition, the isotherm and reusability of the foam for MB adsorption were investigated. These crosslinking processes expanded the potential use of oven-dried CMCNF foams as adsorbents for cationic dyes.

Synergic binding of rhodamine-B and heavy metal ions onto polyethyleneimine grafted freeze-dried chitosan/epichlorohydrin composite beads and possible mechanism.

This paper reports a synergic binding technique of dye and cadmium/lead ions onto freeze-dried modified chitosan beads (GCCS), in this work modified chitosan beads was applied in binary solution. Chitosan beads (CS) composite was produced and polyethyleneimine was grafted onto the backbone of the developed composite. The beads were analyzed utilizing different analytical techniques such as Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). The model applied in pH equilibrium was found to justify the adsorption of pollutants onto the adsorbent. The model was established from 2 equilibrium calculations, one justifying the acid-base attributes of the modified beads, the other elucidating the adsorption of the adsorbates onto the beads, and a mass balance of the various arrangement of nitrogen in the adsorbent. The excellent fit of the Pseudo-second order and intra-particle diffusion kinetic model shows that chemical binding might be the rate-limiting step. The adsorption isotherms were well represented by the Langmuir and Temkin models at a temperature of 45 °C. The maximum binding capacities (Qmax) from the Langmuir model were observed to be 390, 315 and 278 mg/g for the adsorption of dye, lead and cadmium ions respectively`. However, it was found to be higher in the binary system with the same applicable conditions. The correlation was analyzed utilizing various models and lines of best fit were obtained. Synergic effect was observed from the experimental results acquired from the adsorption of Rhodamine B (RHB) and adsorbates. These findings show the formation of fresh binding sites during simultaneous binding process.

Chitosan cross-linked and grafted with epichlorohydrin and 2,4-dichlorobenzaldehyde as an efficient adsorbent for removal of Pb(II) ions from aqueous solution.

Epichlorohydrin-modified chitosan-Schiff base composite (CS/24Cl/ECH) prepared via the one-pot reaction as characterized by Fourier transform Infra-Red spectroscopy (FT-IR), X-ray powder diffraction (XRD), Differential scanning calorimetry (DSC) and Scanning electron microscope (SEM). Its removal ability of Pb(II) ions from aqueous solution was investigated. The adsorption of Pb(II) ions carried out at different initial pH, dose of CS/24-Cl/ECH, contact time and co-existing ions. The maximum adsorption capacity of Pb(II) ions was 170 mg/g. Finally, based on the absorption results, the adsorption of Pb(II) ions was fitted by single-layer Langmuir isotherm model and the pseudo-second-order (PSO) kinetics model. The absorption mechanism of Pb(II) ions was controlled by chemical coordination Pb(II) ions with the active sites on the surface of CS/24Cl/ECH composite. Also, CS/24Cl/ECH showed excellent recyclable efficiency up to 5 cycle and potential sorbent for other heavy metal ions.

Cross-linked chitosan-epichlorohydrin/bentonite composite for reactive orange 16 dye removal: Experimental study and molecular dynamic simulation.

Chitosan/bentonite beads (CsB) composites were prepared from chitosan (Cs) and bentonite (B) and cross-linked with epichlorohydrin for removal of reactive orange 16 (RO16) and methylene blue (MB). The adsorption results have shown that the (Cs20B80), 20 % wt of (Cs) and 80 % (B), was selected as the best adsorbent for (MB) and (RO16) dyes. SEM, EDX, FTIR, BET, and pHpzc were implemented to investigate the features of Cs, B, and Cs20B80 samples. The influence of contact time (0-72 h), initial RO16 concentration (15-300 mg/L), temperature (30, 40, and 50 °C), the quantity of adsorbent (1-4 g/L), ion strength (0.1-1 M), and solution pH (3-10) on RO16 adsorption onto Cs20B80 were explored. The pseudo-second-order and the Langmuir models fit adequately the adsorption kinetic results and the isotherms ones respectively. Also, the maximal monolayer capacities calculated using the non-linear form of the Langmuir isotherm are 55.27, 55.29, and 70.80 mg/g, at 30, 40 and 50 °C. Based to the statistical physics model, the RO16 could be retained on the surface of Cs20B80 through a non-parallel orientation. The RO16 adsorption process is endothermic and natural, as demonstrated by thermodynamic studies. After three regeneration cycles, the Cs20B80 composite has shown an adsorption capacity of around 20 % compared to the initial one. The adsorption energy of RO16 onto Cs, B, and Cs20B80 examined using the Monte Carlo simulation method (MC) ranged from -164.8 to -303.7 (kcal/mol), showing the potential of the three adsorbants for RO16 dye. Also, the process of adsorption of RO16 dye on the surface of Cs20B80 composite indicates several kinds of physical interactions, involving electrostatic interaction, hydrogen bonding, and π-π interactions, this finding was proved theoretically via molecular dynamic simulations.

Binary additives of polyamide epichlorohydrin-nanocellulose for effective valorization of used paper.

This paper presents a binary reinforcement system of polyamide polyamine epichlorohydrin with nanocellulose (PAE-NC) for effectively modification of the reclaimed fibres for paper production, and based on the improvement of physical and mechanical properties of cellulosic fibres together with PAE-NC self-crosslinking networks, the strengthening mechanisms of recycled papers are examined. The PAE-NC binary system was applied directly to old corrugated container (OCC) and softwood bleached kraft pulp (SWBKP), and handsheets are prepared with varying amounts of PAE/NC/PAE-NC, namely 0.05, 0.1, 0.3, 0.5, 0.75, 1.0, 1.5, 2.0 wt% (dry pulp). The results showed that the studied additives improved the performance of recycled fibres, whether SWBKP or OCC pulp, and handsheets in solely or combined mechanisms except for the air permeability of the handsheets. The treatment of PAE-NC combination was significantly more effective than those of PAE or NC alone for both OCC and SWBKP, although the combined PAE-NC treatment results in better performance enhancement for OCC than SWBKP handsheets, and the NC alone is more effective than PAE for SWBKP recycled paper and conversely for OCC recycled paper. SEM observations further confirmed that the combined PAE-NC addition treatment imparted a relatively uniform surface structure to the handsheet.

Epichlorohydrin and tripolyphosphate-crosslinked chitosan-kaolin composite for Auramine O dye removal from aqueous solutions: Experimental study and DFT calculations.

Chitosan (Ch, a natural polymer) and kaolin (K, a natural mineral) composite (Ch-K) was produced with the help of two crosslinkers, epichlorohydrin and tripolyphosphate, and then moulded into uniform beads in tripolyphosphate solution. The synthesis was proved by the analyses involving FT-IR and SEM-EDX. The beads were then used as the natural adsorbent for removal of the auramine O (AO), a frequently-used industrial dye, in aqueous solutions. Adsorbent performance of the Ch-K composite for AO dye molecules was optimized: 500 mg L-1 at pH 7.5 at 25 °C. The Langmuir model found 0.118 mol kg-1 for the maximum adsorption capacity of the Ch-K and the D-R isotherm model showed that the nature of the adsorption process was physical. Kinetics of the adsorption could be explained by using both IPD (intraparticle diffusion) and PSO (pseudo second order) models. Thermodynamic parameters demonstrated that the behaviour of the adsorption was an endothermic and spontaneous. The activity of the composite adsorbent was recovered (88%) after the five sequential adsorption/desorption cycles. Supported by experimental findings, the results obtained from in silico modeling at M06-2X/6-31+G (d,p) level helped hypothesise a mechanism for the formation of the Ch-K composite, and shed some light onto the adsorption behaviour of AO dye by assuming several favourable intermolecular interactions.

Preparation, Characterization and Evaluation of the Anti-Inflammatory Activity of Epichlorohydrin-ß-Cyclodextrin/Curcumin Binary Systems Embedded in a Pluronic®/Hyaluronate Hydrogel.

Curcumin (Cur) is an anti-inflammatory polyphenol that can be complexed with polymeric cyclodextrin (CD) to improve solubility and bioavailability. The aim of the present work was to prepare a CurCD hydrogel to treat inflammatory skin conditions. Epichlorohydrin-ß-CD (EpißCD) was used as polymeric CD. To characterize the binary system, solid-state and in-solution studies were performed. Afterwards, an experimental design was performed to optimize the hydrogel system. Finally, the CurEpißCD hydrogel system was tested for anti-inflammatory activity using a HaCat psoriasis cell model. Co-grinded Cur/EpißCD binary system showed a strong interaction and Curcumin solubility was much improved. Its combination with Pluronic® F-127/hyaluronate hydrogel demonstrated an improvement in release rate and Curcumin permeation. After testing its anti-inflammatory activity, the system showed a significant reduction in IL-6 levels. Hydrogel-containing CurEpißCD complex is a great alternative to treat topical inflammatory diseases.

Preparation and properties of novel bio-based epoxy resin thermosets from lignin oligomers and cardanol.

A series of lignin-based epoxy resins (LEPs) were prepared by the reaction of epichlorohydrin with lignin oligomers derived from partial reductive depolymerization of lignin. To overcome the high viscosity and brittleness defects in practical applications, the LEPs were blended with renewable epoxied cardanol glycidyl ether (ECGE) and then cured with methyltetrahydrophthalic anhydride (MeTHPA) to form high-performance epoxy thermosets. The effects of degree of lignin depolymerization, chemical composition of lignin oligomers and dosage of ECGE on thermal and mechanical properties of the cured products were investigated. The LEP/MeTHPA thermosets exhibited good thermal and mechanical properties. Especially, by separating monomer-rich fractions from lignin oligomers, the thermal and mechanical properties of the cured product were improved obviously. Notably, the incorporation of ECGE also possessed a positive effect on reinforcing and toughening the cured products. With 20 wt% ECGE loadings, the tensile, flexural and impact strength of the cured product reached the maximum value of 77 MPa, 115 MPa and 14 kJ/m2, respectively, which were equivalent to the commercial bisphenol A epoxy resins thermosets. These findings indicated that the novel bio-based epoxy resins from lignin oligomers and cardanol could be utilized as renewable alternatives for BPA epoxy resins.

Preparation of Cross-linked Chitosan Quaternary Ammonium Salt Hydrogel Films Loading Drug of Gentamicin Sulfate for Antibacterial Wound Dressing.

Hydrogels, possessing high biocompatibility and adaptability to biological tissue, show great usability in medical applications. In this research, a series of novel cross-linked chitosan quaternary ammonium salt loading with gentamicin sulfate (CTMCSG) hydrogel films with different cross-linking degrees were successfully obtained by the reaction of chitosan quaternary ammonium salt (TMCS) and epichlorohydrin. Fourier transform infrared spectroscopy (FTIR), thermal analysis, and scanning electron microscope (SEM) were used to characterize the chemical structure and surface morphology of CTMCSG hydrogel films. The physicochemical property, gentamicin sulphate release behavior, cytotoxicity, and antibacterial activity of the CTMCSG against Escherichia coli and Staphylococcus aureus were determined. Experimental results demonstrated that CTMCSG hydrogel films exhibited good water stability, thermal stability, drug release capacity, as well as antibacterial property. The inhibition zone of CTMCSG hydrogel films against Escherichia coli and Staphylococcus aureus could be up to about 30 mm. Specifically, the increases in maximum decomposition temperature, mechanical property, water content, swelling degree, and a reduction in water vapor permeability of the hydrogel films were observed as the amount of the cross-linking agent increased. The results indicated that the CTMCSG-4 hydrogel film with an interesting physicochemical property, admirable antibacterial activity, and slight cytotoxicity showed the potential value as excellent antibacterial wound dressing.

Highly selective removal and recovery of Ni(II) from aqueous solution using magnetic ion-imprinted chitosan nanoparticles.

Nickel (Ni) is one of the most common heavy metals. In this study, nano-sized magnetic ion-imprinted polymers (MIIPs) were synthesized using chitosan as the functional monomer, and used for selective adsorption and recovery of Ni(II) from solutions. The results showed MIIPs possessed high sorption selectivity for Ni(II), and the change in pH (5.0-9.0) exerted insignificant influence on the ion adsorption, allowing almost complete elution and recovery of adsorbed Ni(II) ions by using 0.5% EDTA-Na solution. Moreover, the sorption capacity of the recycled MIIPs decreased by only about 10% after 15 adsorption-desorption cycles. The time required for establishing the adsorption equilibrium was less than 1 h. The sorption process was predominant and endothermic, and could be well described by both Langmuir isotherm model and pseudo-second-order kinetic model. Therefore, the synthesized MIIPs was a suitable adsorbent for highly selective, fast and efficient removal and recovery of low-concentration Ni(II) ions from wastewaters.

Chitin-hydroxyapatite-collagen composite scaffolds for bone regeneration.

Bone defect is usually difficult to recover quickly, and bone scaffold transplantation is considered to be an effective method. Biomaterials have a wide range of application prospects in bone tissue repair, and the two key problems are the selection of materials and cells. The object of this study was to discuss the structural characteristics of bone scaffold materials and their effects on bone repair in vivo. The chitin-hydroxyapatite (HAP)-collagen composite scaffolds (CHCS) was prepared with epichlorohydrin (ECH) as crosslinking agent. The structure was characterized and the compressive strength, porosity, water absorbency and stability were investigated. The biocompatibility and osteogenic differentiation of CHCS in vitro were detected, and the effect of defect repair in vivo was evaluated. The results suggested that HAP not only enhanced the compressive strength of CHCS, but also promoted the formation of calcium nodules due to its bone conductivity. Histological staining showed that collagen promoted collagen deposition and new bone formation. X-ray images also indicated that CHCS transplantation accelerated bone repair. Therefore, CHCs has immense potential in bone regeneration.

Double-crosslinked cellulose nanofiber based bioplastic films for practical applications.

While green bioplastic based on carbohydrate polymers have showed considerable promise, the methods typically used to prepare them in a single material have remained a significant challenge. In this study, a simple approach is proposed to fabricate high performance cellulose films composed of chemically and physically dual-crosslinked 2,2,6,6-tetramethylpiperidine-1-oxy-oxidized cellulose nanofibers (DC TEMPO-CNFs). The hydroxyl groups of TEMPO-CNF suspensions were firstly crosslinked chemically with epichlorohydrin (ECH), and subsequently TEMPO-CNF matrices were crosslinked physically via the strong electrostatic interaction between carboxylate and Ca2+ ions. It was found that the optimized DC TEMPO-CNF films exhibit a good transmittance (90 %) and a high tensile strength (303 MPa). Furthermore, these DC TEMPO-CNF films revealed superior thermal stability and excellent water resistance compared to neat TEMPO-CNF films without crosslinked domains. We believe that these results will pave the way to preparing practical polysaccharide bioplastics with simple, environmentally-friendly manufacturing processes.

Influences of cation valence on water absorbency of crosslinked carboxymethyl cellulose.

Anti-drought is a global challenge. The addition of superabsorbent polymers (SAPs) in soil can lower down the water percolation and evaporation. However, the salt-tolerance and repeating water absorbency (RWA) of prepared SAPs have not satisfied the requirements for implementation. This research investigated the influence of cation valence (Na+, Ca2+ and Al3+) on the structural variations of a crosslinked carboxymethyl cellulose (CCMC) using carboxymethyl cellulose (CMC) cross linked by epichlorohydrin (ECH). The results showed that higher addition of NaOH resulted in higher water absorbency (WA) due to the existence of more carboxyl group. The prepared CCMC sample with 5% CMC and 3% NaOH (CCMC53) was a qualified SAP with WA of 969.0 g/g in deionized water. The salt resistance and the hydrophilicity of sample CCMC53 decreased with the increase of cation valence in the solution. The introduction of Na+ resulted in the replacement of H+ from carboxyl group in sample CCMC53-Na. The coordination of carboxyl group and Ca2+ was bidentate chelating and tridentate bridging for carboxyl group and Al3+. The introduction polyvalent cations benefited the stabilization of carboxyl group, however, retarded the swelling ability of sample CCMC53 and hence resulted in lower WACS. The RWA of sample CCMC53 in deionized water and salt solution dropped the most in the first absorption cycle and then reached constant after a few more cycles. It was necessary to control the first swelling degree of SAP in order to keep the RWA at a higher level.

Performance of phospho-L-tyrosine immobilized onto alginate/polyacrylamide-based cryogels: Effect of ligand coupling on human IgG adsorption and Fab fragments separation.

The ortho-phospho-tyrosine (P-Tyr) pseudoaffinity ligand was immobilized via ether linkage onto polyacrylamide-alginate (PAAm-Alg)-epoxy cryogels prepared according to two different approaches in order to explore their performance in the immunoglobulin G (IgG) purification from human serum. In the first approach, the P-Tyr was attached to cryogel prepared by cryocopolymerization of acrylamide and alginate with allyl glycidyl ether (AGE) as functional comonomer, and methylenebisacrylamide and Ca(II) as crosslinkers, obtaining the PAAm-Alg-AGE-P-Tyr. In the second approach, the PAAm-Alg was synthesized under the same conditions, but without AGE, and the P-Tyr was coupled to epichlorohydrin (ECH)-activated cryogel, obtaining the PAAm-Alg-ECH-P-Tyr. Both pseudoaffinity cryogels were characterized by scanning electron microscopy, swelling tests, porosity, ligand density, and flow dynamics. The human IgG differently interacted with the PAAm-Alg-ECH-P-Tyr and PAAm-Alg-AGE-P-Tyr cryogels, depending on the pH and adsorption buffer system used. The selectivity analyzed by electrophoretic profiles was similar for both cryogels, but PAAm-Alg-ECH-P-Tyr achieved higher IgG adsorption capacity (dynamic capacity of 12.62 mg of IgG/mL of cryogel). The IgG purity assayed by ELISA was 95%. The maximum IgG adsorption capacity and dissociation constant of the PAAm-Alg-ECH-P-Tyr, determined by Langmuir isotherm, were found to be 91.75 mg IgG/g of dry cryogel and 4.60 × 10-6 mol/L at pH 6.0 from aqueous solutions. The PAAm-Alg-AGE-P-Tyr showed potential to purify the Fab fragments from papain-digested human IgG solution at pH 7.0. Fab fragments were separated from Fc fragments (but with uncleaved IgG) in eluted fractions (analyzed by the Western blot technique), with yield of 82% and purity of 95% (determined by radial immunodiffusion).

Thermal deactivation of α-amylase immobilized magnetic chitosan and its modified forms: A kinetic and thermodynamic study.

The stability and thermodynamic properties of an enzyme are the main factors that governing its applications in industry. With that intention we have immobilized the α-amylase onto synthesized chitosan-magnetite (CSM) composite and its modified forms by gluteraldehyde (CSM-GLA), glyoxal (CSM-GLY) and epichlorohydrin (CSM-ECH). In this study all the immobilized enzymes exhibited improved pH stability about 60-80% of relative activity at pH 9 compared to the free enzyme. The temperature stability at 60 °C is up to 50% of relative activity for covalently immobilized enzymes as enzyme become more rigid by covalent binding and so protected from the conformational changes caused by the environment. The thermal deactivation of the free and immobilized enzymes follows the first order kinetics. The t1/2 and D-values were prolonged considerably in case of covalently immobilized enzymes, indicating better thermal stability than that of free and adsorbed ones. The Ed values 18.71, 32.00, 27.19 and 20.46 KJmol-1 for CSM-E, CSM-GLY-E, CSM-GLA-E and CSM-ECH-E described the high stability and resistance to heat inactivation. The Km values 0.525 ± 0.04, 0.57 ± 0.06, 0.65 ± 0.04 mg/mL and Vmax values 25 ± 0.06, 19.6 ± 0.02, 16.39 ± 0.01 µmol mg-1 min-1for CSM-GLY-E, CSM-GLA-E and CSM-ECH-E showing better substrate affinity. The immobilized enzymes have exhibited about 60% of relative activity after 90 days of storage and very good reuse potential.

Statistical optimization and modeling for color removal and COD reduction of reactive blue 19 dye by mesoporous chitosan-epichlorohydrin/kaolin clay composite.

In current research work, chitosan (Chi) was subjected to subsequent physical and chemical modifications by incorporating kaolin clay (KA) into its polymeric structure, and crosslinking process with a covalent cross-linker namely epichlorohydrin (ECH) respectively. The final product of crosslinked chitosan-epichlorohydrin/kaolin (Chi-ECH/KA) composite was successfully applied for color removal and chemical oxygen demand (COD) reduction of textile dye namely reactive blue 19 dye (RB19) from aqueous environment. The influence of pertinent parameters, i.e. A: Chi-ECH/KA dose (0.02-0.1 g), B: pH (4-10), and C: time (5-30 min) on the RB19 color removal and COD reduction were statistically optimized by using response surface methodology with Box-Behnken design (RSM-BBD). The experimental data of the adsorption kinetic and the adsorption isotherm demonstrated a better fitness to pseudo-second order model and Langmuir isotherm model respectively. Excellent absorption ability of 560.9 mg/g was recorded for Chi-ECH/KA composite. The calculated thermodynamic functions clarified that the RB19 adsorption process was endothermic and spontaneous in nature. The mechanism of RB19 adsorption onto the Chi-ECH/KA may include electrostatic interactions, hydrogen bonding, Yoshida H-bonding, and n-π interactions. This study introduces Chi-ECH/KA composite as an eco-friendly, potential and multi-function composite bio adsorbent for removal of textile dye and COD reduction from aqueous environment.

Crosslinked porous three-dimensional cellulose nanofibers-gelatine biocomposite scaffolds for tissue regeneration.

Gelatine is a biocompatible and natural polymer with chemical properties similar to the extracellular matrix. However, it has poor mechanical properties and sensitive to enzymatic biodegradation that limits its application in 3D scaffold fabrication. Cellulose nanofibrous (CNF) offers biocompatibility, high surface area and excellent mechanical properties with slow in-vivo degradation. To fine tune their properties, CNF, and gelatine (CNF-GEL) were blended to form biocomposite aerogels. Epichlorohydrin (EPH) was incorporated into CNF-GEL as a chemical crosslinker to investigate its effect on the physiochemical, mechanical, and biological properties of the biocomposite aerogels both in-vitro and in-vivo. Regardless of the composition of the prepared aerogels, they possessed porosity of >90% with the pore size of 7-135 µm, which was confirmed in the morphological analysis. The presence of EPH improved the chemical interaction between CNF and gelatine, hence enhanced the compressive strength compared to uncrosslinked samples. The formulation of crosslinked CNF-GEL 90:10 offered the highest compressive strength of 61.35 kPa. The in-vitro and in-vivo studies showed adequate cytocompatibility, cell viability and cell attachment in the optimal crosslinked formulation with tuned enzymatic degradation. Antimicrobial property was also achieved in the optimal scaffold by incorporating curcumin as an antimicrobial agent.

Preparation of chitosan aerogel crosslinked in chemical and ionical ways by non-acid condition for wound dressing.

Herein, the dual-crosslinked chitosan aerogel was prepared using 1-butyl-3-methylimidazolium chloride, an ionic liquid, as a solvent. The hydroxyl groups were covalently crosslinked by epichlorohydrin (ECH), while the amino groups were ionically crosslinked by itaconic acid (IA). The chemical and ionic crosslinkings of the aerogels were analyzed using FT-IR and NMR. Both the types and the degree of crosslinking gave significant influences on the structures of the aerogels. The dual crosslinked aerogel with proper chemical crosslinking dose had the excellent swelling behavior. The prepared aerogel shows potential as a wound healing matrix, with low toxicity and antibacterial function.

Fabrication of a novel nontoxic trichlorophenol-epichlorohydrin-based compound with high antimicrobial activity and thermal stability.

The aim of this study was to modify a discontinued, toxic antiseptic agent 2,4,5-trichlorophenol (TCP) by reacting it with epichlorohydrin (ECH) to obtain a nontoxic novel compound with similar antimicrobial effectiveness. A novel compound named {[1,3-bis(2,4,5-trichlorophenoxy) propan-2-yl] oxy}-3-(2,4,5-trichlorophenoxy) hexan-2-ol (TPTH) was synthesized from this reaction. Chemical and physical structures of the product were characterized by FTIR, MS, Uv-vis, NMR, SEM and TEM. The thermal stability of TPTH was evaluated by conducting thermogravimetric analysis. Biological interactions of the compound were investigated by performing antimicrobial activity and cytotoxicity assays. The compound displayed a good antimicrobial activity where minimum inhibitor concentrations were found to be 0.02, 0.08, and 0.15 µg mL-1 against Staphylococcus aureus (S. aureus), Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli) respectively. Additionally, well diffusion assay demonstrated that, the zone of inhibitions for S. aureus, MRSA and E. coli were 24 mm, 22 mm and 18 mm, respectively. Cytotoxicity assay results revealed that TPTH is nontoxic against cells at effective anti-microbial concentrations. TPTH shows thermal stability up to 220 °C. Results here demonstrate the successful conversion of toxic TCP to a nontoxic form; TPTH with a good anti-microbial activity and thermal stability.