Defensins are naturally occurring antimicrobial peptides secreted in the human body. Mammalian defensins are small, cysteine-rich, cationic peptides, generally consisting of 18–45 amino acids. The antimicrobial activity of defensins arises from their unique amino acid sequence, showing activity against both Gram-positive and Gram-negative bacteria, fungi and enveloped viruses. The use of antimicrobial peptides is rising due to their potential to control biofilm formation and kill microorganisms that are highly tolerant to antibiotics. In free-form, defensins are capable of destroying such microorganisms through numerous mechanisms mainly the carpet, the toroidal and the Barrel-Stave models. However, immobilization of antimicrobial peptides (AMPs) on surfaces with the help of coupling agents and spacers can improve the AMPs’ lifespan and stability in the physiological environment leading to applications for medical devices and implants. Fundamental understanding of both free-form and surface-immobilized defensins is important to design more effective antimicrobial peptides and improve their performance in future developments.
Part of the book: Peptide Synthesis
Extracellular vesicles (EVs) derived from natural resources and human cells are innovative biomaterials with vast potential for a wide range of applications. The applications of EVs are expanding rapidly, particularly in emerging fields such as biomaterialomics, information transfer, data storage, and 3D bioprinting, where principles of synthetic biology also come into play. These versatile structures exhibit diverse morphologies and compositions, depending on their cellular origin. As a result, they have been incorporated as key components in both medical and engineering fields. Their integration into these materials has facilitated research in various areas, including DNA and RNA storage, 3D printing, and mitochondrial transfer. Whilst the sustainable production of EVs using validated and standardized methods remains a significant challenge, it is crucial to acknowledge their tremendous potential and prepare for future scientific breakthroughs facilitated by EVs.
Part of the book: Extracellular Vesicles