Biodegradable polyelectrolyte complexes of chitosan and partially crosslinked dextran phosphate with potential for biomedical applications

Time-pH and time-humidity scaling of ionic conductivity spectra of polyelectrolyte multilayers

In this systematic study, ionic conductivity spectra of poly(diallyl-dimethylammonium)/poly(acrylic acid) (PDADMA/PAA)n polyelectrolyte multilayers (PEMs) are investigated regarding superposition principles. In this context, charge transport as well as charge compensation processes in polyelectrolyte assemblies are discussed. The validity of different scaling concepts is tested to differentiate between changes in the mobility and charge carrier density, caused by the variation of a parameter X, where X is either relative humidity during measurement, or salt concentration or pH during preparation. For the first time, time-X scaling for conductivity spectra of PEMs is reported for all three parameters X, resulting in individual mastercurves. Furthermore, a super-mastercurve can be obtained including variations of all three parameters. Changes in plasticization caused by either varied humidity, pH or ionic strength imply non-constant charge carrier mobilities in accordance with a Summerfield-type of scaling, while the charge carrier density remains constant. Interestingly, for preparation conditions which favor extrinsic charge compensation, significant deviations from such Summerfield-type scaling are observed, indicating a variation of the number density of mobile charge carriers with humidity.

Natural polysaccharides and their derivatives as potential medical materials and drug delivery systems for the treatment of peripheral nerve injuries

Peripheral nerve repair following injury is one of the most serious problems in neurosurgery. Clinical outcomes are often unsatisfactory and associated with a huge socioeconomic burden. Several studies have revealed the great potential of biodegradable polysaccharides for improving nerve regeneration. We review here the promising therapeutic strategies involving different types of polysaccharides and their bio-active composites for promoting nerve regeneration. Within this context, polysaccharide materials widely used for nerve repair in different forms are highlighted, including nerve guidance conduits, hydrogels, nanofibers and films. While nerve guidance conduits and hydrogels were used as main structural scaffolds, the other forms including nanofibers and films were generally used as additional supporting materials. We also discuss the issues of ease of therapeutic implementation, drug release properties and therapeutic outcomes, together with potential future directions of research.

Chitosan - dextran phosphate carbamate hydrogels for locally controlled co-delivery of doxorubicin and indomethacin: From computation study to in vivo pharmacokinetics

The development of synergistic drug combinations is a promising strategy for effective cancer suppression. Here, we report all-polysaccharide biodegradable polyelectrolyte complex hydrogels (DPCS) based on dextran phosphate carbamate (DP) and chitosan (CS) for controlled co-delivery of the anticancer drug doxorubicin (DOX) and the non-steroidal anti-inflammatory drug indomethacin (IND). IND can induce more apoptosis in tumor cells by reducing the level of multidrug resistance-associated protein 1. Based on calculations using density functional theory and zeta potential analysis data, carriers with high drug loading were obtained. The release profile of both drugs from the hydrogels was tuned by changing the molecular weight and functional groups content of the polysaccharides. The optimized DPCS showed a steady release of DOX both in vitro and in vivo, and a gradual release of IND, which constantly induced the action of DOX. Considering all of these benefits, DOX- and IND-loaded DPCS offer a promising long-acting polysaccharide-based antitumor platform.

Curcumin Sustained Release with a Hybrid Chitosan-Silk Fibroin Nanofiber Containing Silver Nanoparticles as a Novel Highly Efficient Antibacterial Wound Dressing

Drug loading in electrospun nanofibers has gained a lot of attention as a novel method for direct drug release in an injury site to accelerate wound healing. The present study deals with the fabrication of silk fibroin (SF)-chitosan (CS)-silver (Ag)-curcumin (CUR) nanofibers using the electrospinning method, which facilitates the pH-responsive release of CUR, accelerates wound healing, and improves mechanical properties. Response surface methodology (RSM) was used to investigate the effect of the solution parameters on the nanofiber diameter and morphology. The nanofibers were characterized via Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), zeta potential, and Dynamic Light Scattering (DLS). CS concentration plays a crucial role in the physical and mechanical properties of the nanofibers. Drug loading and entrapment efficiencies improved from 13 to 44% and 43 to 82%, respectively, after the incorporation of Ag nanoparticles. The application of CS hydrogel enabled a pH-responsive release of CUR under acid conditions. The Minimum Inhibitory Concentration (MIC) assay on E. coli and S. aureus bacteria showed that nanofibers with lower CS concentration cause stronger inhibitory effects on bacterial growth. The nanofibers do not have any toxic effect on cell culture, as revealed by in vitro wound healing test on NIH 3T3 fibroblasts.

Polyelectrolyte Membrane Nanocoatings Aimed at Personal Protective and Medical Equipment Surfaces to Reduce Coronavirus Spreading

The study of the surface of membrane coatings constructed with adsorbed coronavirus (COV) was described to test their suitability for the antiviral activity for application in personal protective and medical equipment. The nanocoating based on polyethyleneimine (PEI) or polystyrene sulfonate (PSS) with metallic nanoparticles incorporated was investigated using the AFM technique. Moreover, the functioning of human lung cells in a configuration with the prepared material with the adsorbed coronavirus was studied using microscopic techniques and flow cytometry. The mean values of the percentage share of viable cells compared with the control differed by a maximum of 22%. The results showed that PEI and PSS membrane layer coatings, modified with chosen metallic nanoparticles (AuNPs, AgNPs, CuNPs, FeNPs) that absorb COV, could support lung cells' function, despite the different distribution patterns of COV on designed surfaces as well as immobilized lung cells. Therefore, the developed membrane nanocoatings can be recommended as material for biomedical applications, e.g., medical equipment surfaces to reduce coronavirus spreading, as they adsorb COV and simultaneously maintain the functioning of the eukaryotic cells.

Recent Progress on Modified Gum Katira Polysaccharides and Their Various Potential Applications

Gum katira polysaccharide is biocompatible and non-toxic, and has antioxidant, anti-microbial, and immunomodulatory properties. It is a natural polysaccharide and exudate derived from the stem bark of Cochlospermum reliogosum Linn. Additionally, it has many traditional medicinal uses as a sedative and for the treatment of jaundice, gonorrhea, syphilis, and stomach ailments. This article provides an overview of gum katira, including its extraction, separation, purification, and physiochemical properties and details of its characterization and pharmacognostic features. This paper takes an in-depth look at the synthetic methods used to modify gum katira, such as carboxymethylation and grafting triggered by free radicals. Furthermore, this review provides an overview of its industrial and phytopharmacological applications for drug delivery and heavy metal and dye removal, its biological activities, its use in food, and the potential use of gum katira derivatives and their industrial applications. We believe researchers will find this paper useful for developing techniques to modify gum katira polysaccharides to meet future demands.

Advances in Protein-Based Nanocarriers of Bioactive Compounds: From Microscopic Molecular Principles to Macroscopical Structural and Functional Attributes

Many proteins can be used to fabricate nanocarriers for encapsulation, protection, and controlled release of nutraceuticals. This review examined the protein-based nanocarriers from microscopic molecular characteristics to the macroscopical structural and functional attributes. Structural, physical, and chemical properties of protein-based nanocarriers were introduced in detail. The spatial size, shape, water dispersibility, colloidal stability, etc. of protein-based nanocarriers were largely determined by the molecular physicochemical principles of protein. Different preparative techniques, including antisolvent precipitation, pH-driven, electrospray, and gelation methods, among others, can be used to fabricate different protein-based nanocarriers. Various modifications based on physical, chemical, and enzymatic approaches can be used to improve the functional performance of these nanocarriers. Protein is a natural resource with a wide range of sources, including plant, animal, and microbial, which are usually used to fabricate the nanocarriers. Protein-based nanocarriers have many advantages in aid of the application of bioactive ingredients to the medical, food, and cosmetic industries.

High-Mobility Fungus-Triggered Biodegradable Ultraflexible Organic Transistors

Biodegradable organic field-effect transistors (OFETs) have drawn tremendous attention for potential applications such as green electronic skins, degradable flexible displays, and novel implantable devices. However, it remains a huge challenge to simultaneously achieve high mobility, stable operation and controllable biodegradation of OFETs, because most of the widely used biodegradable insulating materials contain large amounts of hydrophilic groups. Herein, it is firstly proposed fungal-degradation ultraflexible OFETs based on the crosslinked dextran (C-dextran) as dielectric layer. The crosslinking strategy effectively eliminates polar hydrophilic groups and improves water and solvent resistance of dextran dielectric layer. The device with spin-coated 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) semiconductor and C-dextran dielectric exhibits the highest mobility up to 7.72 cm2 V-1 s-1 , which is higher than all the reported degradable OFETs. Additionally, the device still maintains high performance regardless of in an environment humidity up to 80% or under the extreme bending radius of 0.0125 mm. After completion of their mission, the device can be controllably biodegraded by fungi without any adverse environmental effects, promoting the natural ecological cycles with the concepts of "From nature, for nature". This work opens up a new avenue for realizing high-performance biodegradable OFETs, and advances the process of the "green" electrical devices in practical applications.

Dextran, as a biological macromolecule for the development of bioactive wound dressing materials: A review of recent progress and future perspectives

Skin is the largest organ in the body which plays different roles in maintaining hemostasis. Although this tissue has a high healing potential, severe skin wounds cannot heal without external interventions. Among various treatment strategies, tissue-engineered wound dressings have gained significant attention. In this regard, tremendous progress has been made in the field of tissue engineering to develop constructs with higher healing activities. Material selection and optimization are key factors in development of such dressings. Among different candidates, dextran-based wound dressings have been extensively studied. Dextran is a branched biological macromolecule which is composed of anhydroglucose monomers. Due to its excellent biocompatibility, biodegradability, non-toxicity, modifiable functional groups, and proven clinical safety, dextran has found application in wound healing research. In the current review, applications, challenges, and future perspectives of dextran-based wound dressings will be discussed.

Chitosan/alginate/hyaluronic acid polyelectrolyte composite sponges crosslinked with genipin for wound dressing application

Wound dressing composed of polyelectrolyte complexes (PECs), based on chitosan/alginate/hyaluronic acid (CS/ALG/HYA) crosslinked by genipin, was prepared by freeze-dried molding. Genipin as excellent natural biological crosslinker was chose for high biocompatibility and improving mechanical properties of materials. The CS/ALG/HYA sponges (CAHSs) were characterized by FTIR, XRD, DSC and SEM. Porosity, swelling behavior and mechanical properties and in vitro degradation of CAHSs were investigated. The cytotoxicity assay was carried out on HUVEC cells in vitro and the result proves the good biocompatibility of CAHSs. Hemolysis tests indicated that the prepared CAHSs were non-hemolytic material (hemolysis ratio < 5%, no cytotoxicity). PT and aPPT coagulation tests demonstrated that CAHS2 and CAHS3 could both activate the extrinsic and intrinsic coagulation pathway and thus accelerated blood coagulation. Further, in a rat full-thickness wounds model, the CAHS2 sponge significantly facilitates wound closure compared to other groups. CAHSs exhibited adjustable physical, mechanical and biological properties. Thus, the chitosan-based polyelectrolyte composite sponges exhibit great potential as promising wound dressings.