A self-healing wound dressing hydrogel is prepared through Schiff-base cross-linking between oxidized salep (OSa) and ethylene diamine-modified salep (SaHEA) as first network and physical cross-linking of PVA via freezing-thawing as the second network.

With continual rapid developments in the biomedical field and understanding of the important mechanisms and pharmacokinetics of biological molecules, controlled drug delivery systems (CDDSs) have been at the forefront over conventional drug delivery systems. Over the past several years, scientists have placed boundless energy and time into exploiting a wide variety of excipients, particularly diverse polymers, both natural and synthetic. More recently, the development of nano polymer blends has achieved noteworthy attention due to their amazing properties, such as biocompatibility, biodegradability and more importantly, their pivotal role in controlled and sustained drug release in vitro and in vivo. These compounds come with a number of effective benefits for improving problems of targeted or controlled drug and gene delivery systems; thus, they have been extensively used in medical and pharmaceutical applications. Additionally, they are quite attractive for wound dressings, textiles, tissue engineering, and biomedical prostheses. In this sense, some important and workable natural polymers (namely, chitosan (CS), starch and cellulose) and some applicable synthetic ones (such as poly-lactic-co-glycolic acid (PLGA), poly(lactic acid) (PLA) and poly-glycolic acid (PGA)) have played an indispensable role over the last two decades for their therapeutic effects owing to their appealing and renewable biological properties. According to our data, this is the first review article highlighting CDDSs composed of diverse natural and synthetic nano biopolymers, blended for biological purposes, mostly over the past five years; other reviews have just briefly mentioned the use of such blended polymers. We, additionally, try to make comparisons between various nano blending systems in terms of improved sustained and controlled drug release behavior.

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Carbon-based nanocarriers such as multiwall carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO) have shown promising delivery capabilities due to their low immunogenicity, superior internalization, and suitable cell penetration efficiency. Herein, a molecular engineering strategy is advanced for the one-pot synthesized rGO/MWCNT/Fe 3 O 4 /ZnO to enhance the stability of the nanocarrier in the biological matrix; green synthesized ZnO was responsible for water uptake and reduced cytotoxicity, while Fe 3 O 4 controlled the cellular internalization for gene delivery. Surface morphology of the ensuing nanocomposite was correlated with photocatalytic and gene delivery (CRISPR/Cas9) features. For the first time, a complete physical interaction between CRISPR/Cas9 and nanomaterial is evidenced via atomic force microscopy (AFM), demonstrating an increase in green fluorescence protein (EGFP) up to 11%. Furthermore, the enhanced photocatalytic activity is displayed in complete degradation of the methylene blue dye under 10 min with an efficiency of over 98%. The cytotoxicity of the nanocomposite is enhanced by ZnO on treatment with the PC12 and HEK-293 cell lines subsequent to 24, 48, and 72 h of exposure, with more than 88, 79, and 80% cell viabilities for PC12 and more than 88, 80, and 85% cell viabilities for HEK-293 in the maximum ratio of material to CRISPR (WR of nM/CC being 100). Furthermore, the nanocomposite showed an antibacterial activity against both Staphylococcus aureus and Escherichia coli bacteria (MZI values of 24 and 21 mm, respectively). The surface chemistry of the optimized system opens up new prospects to codeliver therapeutic agents for useful clinical applications.

A number of synthetic hydrogels suffer from low mechanical strength. Despite of the recent advances in the fabrication of tough hydrogels, it is still a great challenge to simultaneously construct high stretchability, and self‐adhesive and self‐healing capability in a hydrogel. Herein, a new type of double network hydrogel was prepared based on irreversible cross‐linking of polyacrylamide chains and Schiff‐base reversible cross‐linking between glycidyl methacrylate‐grafted ethylenediamine and oxidized sodium alginate (OSA). The combination of both cross‐linkings and their synergistic effect provided a novel hydrogel with high strength, stretchable, rapid self‐healing, and self‐adhesiveness to different material. Besides, the hydrogels with diverse OSA content could maintain their original shapes after loading–unloading tensile test. The resulting hydrogel has a great potential in various fields for supporting and load‐bearing substance.

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