Silk fibroin nanofibers containing chondroitin sulfate and silver sulfadiazine for wound healing treatment

Recent advance for animal-derived polysaccharides in nanomaterials

Inspired by the structure characteristics of natural products, the size and morphology of particles are carefully controlled using a bottom-up approach to construct nanomaterials with specific spatial unit distribution. Animal polysaccharide nanomaterials, such as chitosan and chondroitin sulfate nanomaterials, exhibit excellent biocompatibility, degradability, customizable surface properties, and novel physical and chemical properties. These nanomaterials hold great potential for development in achieving a sustainable bio-economy. This paper provides a summary of the latest research results on the preparation of nanomaterials from animal polysaccharides. The mechanism for preparing nanomaterials through the bottom-up method from different sources of animal polysaccharides is introduced. Furthermore, this paper discusses the potential hazards posed by industrial applications to the environment and human health, as well as the challenges and future prospects associated with using animal polysaccharides in nanomaterials.

Reduced TiO2 Nanotubes/Silk Fibroin/ZnO as a Promising Hybrid Antibacterial Coating

The current research aims to elucidate the influence of reduction process of TiO2 nanostructures on the surface properties of a bioinspired Ti modified implant, considering that the interface between a biomaterial surface and the living tissue plays an important role for this interaction. The production of reduced TiO2 nanotubes (RNT) with lower band gap is optimized and their performance is compared with those of simple TiO2 nanotubes (NT). The more conductive surfaces provided by the presence of RNT on Ti, allow a facile deposition of silk fibroin (SF) film using the electrochemical deposition method. This hybrid film is then functionalized with ZnO nanoparticles, to improve the antibacterial effect of the coating. The modified Ti surface is evaluated in terms of surface chemistry, morphology and roughness, wettability, surface energy, surface charge and antibacterial properties. Surface analysis such as SEM, AFM, FTIR and contact angle measurements were performed to obtain topographical features and wettability. FT-IR analysis confirms that SF was effectively attached to TiO2 nanotubes surfaces. The electrochemical deposition of SF and SF-ZnO reduced the interior diameter of nanotubes from ~85 nm to approx. 50-60 nm. All modified surfaces have a hydrophilic character.

Trends in the Incorporation of Antiseptics into Natural Polymer-Based Nanofibrous Mats

Nanofibrous materials represent a very promising form of advanced carrier systems that can be used industrially, especially in regenerative medicine as highly functional bandages, or advanced wound dressings. By incorporation of antimicrobial additives directly into the structure of the nanofiber carrier, the functionality of the layer is upgraded, depending on the final requirement-bactericidal, bacteriostatic, antiseptic, or a generally antimicrobial effect. Such highly functional nanofibrous layers can be prepared mostly by electrospinning technology from both synthetic and natural polymers. The presence of a natural polymer in the composition is very advantageous. Especially in medical applications where, due to the presence of the material close to the human body, the healing process is more efficient and without the occurrence of an unwanted inflammatory response. However, converting natural polymers into nanofibrous form, with a homogeneously distributed and stable additive, is a great challenge. Thus, a combination of natural and synthetic materials is often used. This review clearly summarizes the issue of the incorporation and effectiveness of different types of antimicrobial substances, such as nanoparticles, antibiotics, common antiseptics, or substances of natural origin, into electrospun nanofibrous layers made of mostly natural polymer materials. A section describing the problematic aspects of antimicrobial polymers is also included.

Green Synthesis of Polycyclodextrin/Drug Inclusion Complex Nanofibrous Hydrogels: pH-Dependent Release of Acyclovir

The development of an approach or a material for wound healing treatments has drawn a lot of attention for decades and has been an important portion of the research in the medical industry. Especially, there is growing interest and demand for the generation of wound care products using eco-friendly conditions. Electrospinning is one of these methods that enables the production of nanofibrous materials with attractive properties for wound healing under mild conditions and by using sustainable sources. In this study, starch-derived cyclodextrin (hydroxypropyl-β-cyclodextrin (HPβCD)) was used both for forming an inclusion complex (IC) with acyclovir, a well-known antiviral drug, and for electrospinning of free-standing nanofibers. The nanofibers were produced in an aqueous system, without using a carrier polymer matrix and toxic solvent/chemical. The ultimate HPβCD/acyclovir-IC nanofibers were thermally cross-linked by using citric acid, listed in the generally regarded as safe (GRAS) category by the US Food and Drug Administration (FDA). The cross-linked HPβCD/acyclovir-IC nanofibers displayed stability in aqueous medium. The hydrogel-forming feature of nanofibers was confirmed with their high swelling profile in water in the range of ∼610-810%. Cellulose acetate (CA)/acyclovir nanofibers were also produced as the control sample. Due to inclusion complexation with HPβCD, the solubility of acyclovir was improved, so cross-linked HPβCD/acyclovir-IC nanofibrous hydrogels displayed a better release performance compared to CA/acyclovir nanofibers. Here, a pH-dependent release profile was obtained (pH 5.4 and pH 7.4) besides their attractive swelling features. Therefore, the cross-linked HPβCD/acyclovir-IC nanofibrous hydrogel can be a promising candidate as a wound healing dressing for the administration of antiviral drugs by holding the unique properties of CD and electrospun nanofibers.

Silk Fibroin/ZnO Coated TiO2 Nanotubes for Improved Antimicrobial Effect of Ti Dental Implants

The aim of the present research is to develop a novel hybrid coating for a Ti dental implant that combines nature-inspired biomimetic polymers and TiO2 nanostructures with an entrapped ZnO antimicrobial agent. ZnO was used in other studies to cover the surface of Ti or Ti-Zr to reduce the need of clinical antibiotics, prevent the onset of peri-implantitis, and increase the success rate of oral clinical implantation. We developed an original coating that represents a promising approach in clinical dentistry. The titanium surface was first anodized to obtain TiO2 nanotubes (NT). Subsequently, on the NT surface, silk fibroin isolated from Bombyx mori cocoons was deposited as nanofibers using the electrospun technique. For an improved antibacterial effect, ZnO nanoparticles were incorporated in this biopolymer using three different methods. The surface properties of the newly created coatings were assessed to establish how they are influenced by the most important features: morphology, wettability, topography. The evaluation of stability by electrochemical methods in simulated physiological solutions was discussed more in detail, considering that it could bring necessary information related to the behavior of the implant material. All samples had improved roughness and hydrophilicity, as well as corrosion stability (with protection efficiency over 80%). The antibacterial test shows that the functional hybrid coating has good antibacterial activity because it can inhibit the proliferation of Staphylococcus aureus up to 53% and Enterococcus faecalis up to 55%. All Ti samples with the modified surface have proven superior properties compared with unmodified TiNT, which proved that they have the potential to be used as implant material in dentistry.

Chondroitin sulfate-based composites: a tour d'horizon of their biomedical applications

Chondroitin sulfate (CS), a natural anionic mucopolysaccharide, belonging to the glycosaminoglycan family, acts as the primary element of the extracellular matrix (ECM) of diverse organisms. It comprises repeating units of disaccharides possessing β-1,3-linked N-acetyl galactosamine (GalNAc), and β-1,4-linked D-glucuronic acid (GlcA), and exhibits antitumor, anti-inflammatory, anti-coagulant, anti-oxidant, and anti-thrombogenic activities. It is a naturally acquired bio-macromolecule with beneficial properties, such as biocompatibility, biodegradability, and immensely low toxicity, making it the center of attention in developing biomaterials for various biomedical applications. The authors have discussed the structure, unique properties, and extraction source of CS in the initial section of this review. Further, the current investigations on applications of CS-based composites in various biomedical fields, focusing on delivering active pharmaceutical compounds, tissue engineering, and wound healing, are discussed critically. In addition, the manuscript throws light on preclinical and clinical studies associated with CS composites. A short section on Chondroitinase ABC has also been canvassed. Finally, this review emphasizes the current challenges and prospects of CS in various biomedical fields.