N , N , N -trimethylchitosan modified with well defined multifunctional polymer modules used as pDNA delivery vector

Integrating synthetic polypeptides with innovative material forming techniques for advanced biomedical applications

Polypeptides are highly valued in biomedical science for their biocompatibility and biodegradability, making them valuable in drug delivery, tissue engineering, and antibacterial dressing. The diverse design of polymer chains and self-assembly techniques allow different side chains and secondary structures, enhancing their biomedical potential. However, the traditional solid powder form of polypeptides presents challenges in skin applications, shipping, and recycling, limiting their practical utility. Recent advancements in material forming methods and polypeptide synthesis have produced biomaterials with uniform, distinct shapes, improving usability. This review outlines the progress in polypeptide synthesis and material-forming methods over the past decade. The main synthesis techniques include solid-phase synthesis and ring-opening polymerization of N-carboxyanhydrides while forming methods like electrospinning, 3D printing, and coating are explored. Integrating structural design with these methods is emphasized, leading to diverse polypeptide materials with unique shapes. The review also identifies research hotspots using VOSviewer software, which are visually presented in circular packing images. It further discusses emerging applications such as drug delivery, wound healing, and tissue engineering, emphasizing the crucial role of material shape in enhancing performance. The review concludes by exploring future trends in developing distinct polypeptide shapes for advanced biomedical applications, encouraging further research.

Multi-responsive Pickering emulsifiers: a comprehensive study on the emulsification-demulsification behavior of modified chitosan-coated Fe3O4 nanocomposites

The surface characteristics of stimuli-responsive Pickering emulsifiers can be modified by external environmental triggers, making them highly versatile in various applications. In this study, we report three novel organic-inorganic composite structure emulsifiers. These emulsifiers were designed with a core of magnetic Fe3O4 particles, surrounded by a protective silica layer, and coated on the exterior with three distinct types of modified chitosan (CS). Experimental results demonstrate that these emulsifiers can stabilize emulsion systems consisting of liquid paraffin and deionized water at a concentration of 0.5 wt%. The unique properties of the modified CS coatings allowed for the controlled demulsification of two types of emulsions by adjusting the proton concentration. Additionally, these emulsifiers exhibited magnetic-responsive demulsification under the control of an external magnetic field. The findings of this study provide valuable insights into the design and construction of multi-responsive chitosan-based magnetic Pickering emulsifiers with controllable properties.

The Role of Angiogenesis-Inducing microRNAs in Vascular Tissue Engineering

Angiogenesis is an important process in tissue repair and regeneration as blood vessels are integral to supply nutrients to a functioning tissue. In this review, the application of microRNAs (miRNAs) or anti-miRNAs that can induce angiogenesis to aid in blood vessel formation for vascular tissue engineering in ischemic diseases such as peripheral arterial disease and stroke, cardiac diseases, and skin and bone tissue engineering is discussed. Endothelial cells (ECs) form the endothelium of the blood vessel and are recognized as the primary cell type that drives angiogenesis and studied in the applications that were reviewed. Besides ECs, mesenchymal stem cells can also play a pivotal role in these applications, specifically, by secreting growth factors or cytokines for paracrine signaling and/or as constituent cells in the new blood vessel formed. In addition to delivering miRNAs or cells transfected/transduced with miRNAs for angiogenesis and vascular tissue engineering, the utilization of extracellular vesicles (EVs), such as exosomes, microvesicles, and EVs collectively, has been more recently explored. Proangiogenic miRNAs and anti-miRNAs contribute to angiogenesis by targeting the 3'-untranslated region of targets to upregulate proangiogenic factors such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor, and hypoxia-inducible factor-1 and increase the transduction of VEGF signaling through the PI3K/AKT and Ras/Raf/MEK/ERK signaling pathways such as phosphatase and tensin homolog or regulating the signaling of other pathways important for angiogenesis such as the Notch signaling pathway and the pathway to produce nitric oxide. In conclusion, angiogenesis-inducing miRNAs and anti-miRNAs are promising tools for vascular tissue engineering for several applications; however, future work should emphasize optimizing the delivery and usage of these therapies as miRNAs can also be associated with the negative implications of cancer.

Biodegradable Polymers for Gene-Delivery Applications

Gene-based therapies have emerged as a new modality for combating a myriad of currently incurable diseases. However, the fragile nature of gene therapeutics has significantly hampered their biomedical applications. Correspondingly, the development of gene-delivery vectors is of critical importance for gene-based therapies. To date, a variety of gene-delivery vectors have been created and utilized for gene delivery. In general, they can be categorized into viral- and non-viral vectors. Due to safety issues associated with viral vectors, non-viral vectors have recently attracted much more research focus. Of these non-viral vectors, polymeric vectors, which have been preferred due to their low immunogenicity, ease of production, controlled chemical composition and high chemical versatility, have constituted an ideal alternative to viral vectors. In particular, biodegradable polymers, which possess advantageous biocompatibility and biosafety, have been considered to have great potential in clinical applications. In this context, the aim of this review is to introduce the recent development and progress of biodegradable polymers for gene delivery applications, especially for their chemical structure design, gene delivery capacity and additional biological functions. Accordingly, we first define and categorize biodegradable polymers, followed by describing their corresponding degradation mechanisms. Various types of biodegradable polymers resulting from natural and synthetic polymers will be introduced and their applications in gene delivery will be examined. Finally, a future perspective regarding the development of biodegradable polymer vectors will be given.

Chitosan for gene delivery: Methods for improvement and applications

Gene therapy is a promising strategy for treating challenging diseases. The successful delivery of genes is a critical step for gene therapy. However, concerns about immunogenicity and toxicity are the main obstacles against the widespread use of effective viral systems. Therefore, nonviral vectors are regarded as good alternatives to viral vectors. Chitosan is a natural cationic polysaccharide that could be used to create nonviral gene delivery vectors. Various methods have been developed to improve the properties of chitosan related to gene delivery. This review introduces the features of chitosan in gene delivery, summarizes current progress toward methods promoting the properties of chitosan related to gene delivery, and presents different applications of chitosan in gene delivery vectors. Finally, future prospects of gene vectors based on chitosan are discussed.

Protein moiety in oligochitosan modified vector regulates internalization mechanism and gene delivery: Polyplex characterization, intracellular trafficking and transfection

Oligochitosan-modified proteins have gained attention as efficient non-viral vectors for gene delivery. However, little information exists if protein moieties can serve as an important role for internalization and endosome escape ability of the genetic material. To explore this issue, we designed two cationic oligochitosan-modified vectors that consist of different proteins, namely a hydrophobic plant protein (zein) and a hydrophilic animal protein (ovalbumin (OVA)) to deliver pDNA to epithelial cell line CHO-K1 and HEK 293 T. These cationic vectors were systematically characterized by molecular weight, infrared (IR) structural analysis, transmission electron microscopy (TEM) morphology, and surface charge. A remarkable impact of protein moieties was observed on physiochemical properties of the developed vectors. Oligochitosan-modified zein containing hydrophobic protein exhibited high buffering capacity and excellent DNA binding ability compared to the oligochitosan-modified OVA. The data on transfection in the presence of endocytic inhibitors indicated that the caveolae-mediated pathway (CvME) played a key role in the internalization of the zein-based polyplex. However, the OVA-based polyplex was internalized in CHO-K1 cells via CvME and in HEK 293 T cells via the lipid-mediated pathway. Moreover, oligochitosan-modified zein exhibited lower cytotoxicity, greater lysosomal escape ability, better plasmid stability, and better transfection efficiency than the oligochitosan-modified OVA. This study offers a facile procedure for the synthesis of cationic vectors and elucidates the relationship that exists between protein moieties and transfection activity, thus providing an alternative, non-viral platform for the gene delivery.