Water absorption and moisture permeation properties of chitosan/poly(acrylamide-co-itaconic acid) IPC films

Production and characterization of starch-lignin based materials: A review

In their pristine state, starch and lignin are abundant and inexpensive natural polymers frequently considered green alternatives to oil-based and synthetic polymers. Despite their availability and owing to their physicochemical properties; starch and lignin are not often utilized in their pristine forms for high-performance applications. Generally, chemical and physical modifications transform them into starch- and lignin-based materials with broadened properties and functionality. In the last decade, the combination of starch and lignin for producing reinforced materials has gained significant attention. The reinforcing of starch matrices with lignin has received primary focus because of the enhanced water sensitivity, UV protection, and mechanical and thermal resistance that lignin introduces to starch-based materials. This review paper aims to assess starch-lignin materials' production and characterization technologies, highlighting their physicochemical properties, outcomes, challenges, and opportunities. First, this paper describes the current status, sources, and chemical modifications of lignin and starch. Next, the discussion is oriented toward starch-lignin materials and their production approaches, such as blends, composites, plasticized/crosslinked films, and coupled polymers. Special attention is given to the characterization methods of starch-lignin materials, focusing on their advantages, disadvantages, and expected outcomes. Finally, the challenges, opportunities, and future perspectives in developing starch-lignin materials, such as adhesives, coatings, films, and controlled delivery systems, are discussed.

Mucoadhesive chitosan-methylcellulose oral patches for the treatment of local mouth bacterial infections

Mucoadhesive buccal patches are dosage forms promising for successful drug delivery. They show the distinctive advantages of long residence time on the oral mucosa and increased in situ drug bioavailability. In this context, electrophoretic deposition (EPD) of chitosan (CS) has been demonstrated as a simple and easily tunable technique to produce mucoadhesive buccal patches. However, CS-based buccal patches may suffer from weak mucoadhesion, which can impair their therapeutic effect. In this work, methylcellulose (MC), a widely investigated biopolymer in the biomedical area, was exploited to increase the mucoadhesive characteristic of pristine CS patches. CS-MC patches were obtained in a one-pot process via EPD, and the possibility of incorporating gentamicin sulfate (GS) as a model of a broad-spectrum antibiotic in the so-obtained patches was investigated. The resulting CS-MC patches showed high stability in a water environment and superior mucoadhesive characteristic (σ_adh = 0.85 ± 0.26 kPa, W_adh = 1192.28 ± 602.36 Pa mm) when compared with the CS control samples (σ_adh = 0.42 ± 0.22 kPa, W_adh = 343.13 ± 268.89 Pa mm), due to both the control of the patch porosity and the bioadhesive nature of MC. Furthermore, GS-loaded patches showed no in vitro cytotoxic effects by challenging L929 cells with material extracts and noteworthy antibacterial activity on both Gram-positive and Gram-negative bacterial strains.

Graphene oxide incorporated chitosan/acrylamide/itaconic acid semi-interpenetrating network hydrogel bio-adsorbents for highly efficient and selective removal of cationic dyes

In recent years, polymeric bio-adsorbents offers high removal efficiency, superior adsorption capacity and selectivity against various pollutants in aqueous medium. While designing these adsorbents, their environmental friendliness, sustainability, renewability, easy accessibility, and cost-effectiveness should be considered. In this study, GO incorporated semi-interpenetrating network (semi-IPN) nanocomposite hydrogels (CS/AAm/IA/GO) were obtained by free radical copolymerization of acrylamide (AAm) and itaconic acid (IA) in the presence of chitosan (CS) as an environmentally friendly bio-adsorbent. GO significantly improved the thermal stability, compressive strength, and percentage swelling of the hydrogel. The selective adsorption studies demonstrated that methylene blue (MB) was the most efficiently removed dye from both individual and mixed dye systems with 99.8 % removal efficiency. The adsorption capacity was found to be 247.47 mg g^-1 using 0.025 g hydrogel adsorbent containing 0.5 wt% of GO and an initial MB concentration of 5 mg L^-1 at pH 8 over 90 min at room temperature. The kinetic and isotherm studies revealed that the adsorption process followed the pseudo-second-order kinetic model and Langmuir adsorption isotherm. Thermodynamic studies suggested the spontaneous and endothermic nature of MB adsorption. Also, the MB removal efficiency above 96 % was obtained after 7 consecutive adsorption-desorption cycles while maintaining the structural stability of the bio-adsorbent.

Adsorption of cationic dyes onto carrageenan and itaconic acid-based superabsorbent hydrogel: Synthesis, characterization and isotherm analysis

Polysaccharide-based hydrogels offer a great overlook for environmental applications and help in the elimination of various noxious pollutants from the water system. Novel carrageenan and itaconic acid-based superadsorbent hydrogel having appreciable swelling properties and adsorption capacity towards Methylene blue (MB), Crystal violet (CV), and Methyl Red (MR) was synthesized by suspension polymerization technique. The swelling study showed the dependency upon the temperature in which the swelling rate increased with increasing temperature with a maximum swelling rate of 417% at 318 K. For ascertaining the maximum adsorption capacity, various influential parameters such as contact time, adsorbent dose, dye concentration, and temperature were systematically studied. Maximum adsorption capacity as calculated from the Langmuir isotherm was 2439.02, 1111.11, and 666.68 mg/g for MB, CV, and MR, respectively. Thermodynamic studies revealed the spontaneous nature of the undertaken dye adsorption experiment. Overall, the present study reveals that the synthesized superadsorbent hydrogel can be used as an efficient adsorbent for the removal of dyes from an aqueous solution.

3D collagen matrices modulate the transcriptional trajectory of bone marrow hematopoietic progenitors into macrophage lineage commitment

Physical signals provided by the extracellular matrix (ECM) are key microenvironmental parameters for the fate decision of hematopoietic stem and progenitor cells (HSPC) in bone marrow. Insights into cell-ECM interactions are critical for advancing HSC-based tissue engineering. Herein, we employed collagen hydrogels and collagen-alginate hydrogels of defined stiffness to study the behaviors of hematopoietic progenitor cells (HPCs). Three-dimensional (3D) collagen hydrogels with a stiffness of 45 Pa were found to promote HPC maintenance and colony formation of monocyte/macrophage progenitors. Using single-cell RNA sequencing (scRNA-seq), we also characterized the comprehensive transcriptional profiles of cells randomly selected from two-dimensional (2D) and 3D hydrogels. A distinct maturation trajectory from HPCs into macrophages within the 3D microenvironment was revealed by these results. 3D-derived macrophages expressed high levels of various cytokines and chemokines, such as Saa3, Cxcl2, Socs3 and Tnf. Furthermore, enhanced communication between 3D-macrophages and other hematopoietic clusters based on ligand-repair interactions was demonstrated through bioinformatic analyses. Our research underlines the regulatory role of matrix-dimensionality in HPC differentiation and therefore probably be applied to the generation of specialized macrophages.

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3D collagen hydrogels influenced the maintenance of hematopoietic progenitor cells.

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3D matrices modulated the lineage specification of hematopoietic progenitors and promoted the formation of CFU-M colonies.

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Single-cell RNA sequencing identified a cluster of specialized macrophages within a 3D microenvironment.

β-cyclodextrin chitosan-based hydrogels with tunable pH-responsive properties for controlled release of acyclovir: design, characterization, safety, and pharmacokinetic evaluation

In this work, series of pH-responsive hydrogels (FMA1–FMA9) were synthesized, characterized, and evaluated as potential carrier for oral delivery of an antiviral drug, acyclovir (ACV). Different proportions of β-cyclodextrin (β-CD), chitosan (CS), methacrylic acid (MAA) and N′ N′-methylenebis-acrylamide (MBA) were used to fabricate hydrogels via free radical polymerization technique. Fourier transform infrared spectroscopy confirmed fabrication of new polymeric network, with successful incorporation of ACV. Scanning electron microscopy (SEM) indicated presence of slightly porous structure. Thermal analysis indicated enhanced thermal stability of polymeric network. Swelling studies were carried out at 37 °C in simulated gastric and intestinal fluids. The drug release data was found best fit to zero-order kinetics. The preliminary investigation of developed hydrogels showed a pH-dependent swelling behavior and drug release pattern. Acute oral toxicity study indicated no significant changes in behavioral, clinical, or histopathological parameters of Wistar rats. Pharmacokinetic study indicated that developed hydrogels caused a significant increase in oral bioavailability of ACV in rabbit plasma as compared to oral suspension when both were administered at a single oral dose of 20 mg kg⁻¹ bodyweight. Hence, developed hydrogel formulation could be used as potential candidate for controlled drug delivery of an antiviral drug acyclovir.

Effects of caprolactam content on curdlan-based food packaging film and detection by infrared spectroscopy

In this study, we report a rapid statistical approach used in determining the caprolactam (CPL) content in curdlan packaging films, which is based on the spectral data observed in the near-infrared (NIR) and Mid-infrared (MIR) regions. At the first stage of the study, the CPL content was added into the curdlan films prepared by controlling the concentration, and then the effect of the CPL concentration on the measured mechanical properties of the produced films were evaluated. At the next stage, the NIR and MIR spectra of the curdlan films with different CPL concentrations were recorded by using the FT-NIR and FT-IR spectroscopy technique, and the spectral data to be used in the regression models in our quantitative analyses were carefully selected. It was observed that the curdlan film with 5% CPL exhibited the best mechanical properties. The obtained best correlation parameters which are used in evaluation of CPL content through the observed NIR and MIR spectral data are Rp = 0.9552, RMSEP = 1.2506 (NIR); Rp = 0.9092 and RMSEP = 1.9136 (MIR), respectively. These optimal values support the expectation that our statistical approach based on NIR and MIR data can provide a rapid, accurate and nondestructive way of determining CPL content in curdlan packaging films.

Bioplatform Fabrication Approaches Affecting Chitosan-Based Interpolymer Complex Properties and Performance as Wound Dressings

Chitosan can form interpolymer complexes (IPCs) with anionic polymers to form biomedical platforms (BMPs) for wound dressing/healing applications. This has resulted in its application in various BMPs such as gauze, nano/microparticles, hydrogels, scaffolds, and films. Notably, wound healing has been highlighted as a noteworthy application due to the remarkable physical, chemical, and mechanical properties enabled though the interaction of these polyelectrolytes. The interaction of chitosan and anionic polymers can improve the properties and performance of BMPs. To this end, the approaches employed in fabricating wound dressings was evaluated for their effect on the property-performance factors contributing to BMP suitability in wound dressing. The use of chitosan in wound dressing applications has had much attention due to its compatible biological properties. Recent advancement includes the control of the degree of crosslinking and incorporation of bioactives in an attempt to enhance the physicochemical and physicomechanical properties of wound dressing BMPs. A critical issue with polyelectrolyte-based BMPs is that their effective translation to wound dressing platforms has yet to be realised due to the unmet challenges faced when mimicking the complex and dynamic wound environment. Novel BMPs stemming from the IPCs of chitosan are discussed in this review to offer new insight into the tailoring of physical, chemical, and mechanical properties via fabrication approaches to develop effective wound dressing candidates. These BMPs may pave the way to new therapeutic developments for improved patient outcomes.

Floating molecularly imprinted polymers based on liquid crystalline and polyhedral oligomeric silsesquioxanes for capecitabine sustained release

Molecularly imprinted polymers (MIPs) have drawn extensive attention as carriers on drug delivery. However, most of MIPs suffer from insufficient drug loading capacity, burst release of drugs and/or low bioavailability. To solve the issues, this study designed an imprinted material with superior floating nature for oral drug delivery system of capecitabine (CAP) rationally. The MIPs was synthesized in the presence of 4-methylphenyl dicyclohexyl ethylene (liquid crystalline, LC) and polyhedral oligomeric silsesquioxanes (POSS) via polymerization reaction. The LC-POSS MIPs had extended release of the template molecules over 13.4 h with entrapment efficiency of 20.53%, diffusion coefficient of 2.83 × 10^-11 cm² s^-1, and diffusion exponent of 0.84. Pharmacokinetic studies further revealed the prolong release and high relative bioavailability of CAP in vivo of rats, showing the effective floating effect of the LC-POSS MIPs. The in vivo images revealed visually that the gastroretentive time of the LC-POSS MIPs was longer than non-LC-POSS imprinted polymers. The physical characteristics of the polymers were also characterized by nitrogen adsorption experiment, scanning electron microscopy, thermogravimetric analysis and differential scanning calorimetry analysis. As a conclusion, the LC-POSS MIPs can be used as an eligible CAP carrier and might hold great potential in clinical applications for sustained release drug.

Biophysical and biological characterization of intraoral multilayer membranes as potential carriers: A new drug delivery system for dentistry

The current study developed through layer-by-layer deposition a multilayer membrane for intraoral drug delivery and analyzed the biochemical, functional, and biological properties of this membrane. For that purpose, we designed a three-layer chlorhexidine-incorporated membrane composed by pure chitosan and alginate. The biochemical, functional, and biological properties were analyzed by the following tests: degradation in saliva medium; controlled drug release; water absorption, mass loss; pH analysis; and biocompatibility through fibroblast cell viability by MTT assay. All tests were conducted at three different periods (24, 48 and 72hours). The results demonstrated that hybrid membranes composed by alginate and chitosan with glycerol had greater water absorption and mass loss in buffer solution and in artificial saliva. The controlled drug release test revealed that the hybrid membrane exhibited greater drug release (0.075%). All chlorhexidine-incorporated membranes reduced the cell viability, and chitosan membranes with and without glycerol did not interfere with fibroblast viability. The biochemical and biophysical characteristics of the designed membranes and the findings of cell viability tests indicate great potential for application in Dentistry.