Applications of Biodegradable Polymeric Nanomaterials as Drug Delivery Systems.

There are a variety of biodegradable polymers, including natural polysaccharides, proteins, nucleic acids, etc., in animals and plants, as well as some polymers that are synthesized by microorganisms, such as poly(3-hydroxybutyrate-co-3-hydroxyhexanoate). At present, the most common polymers are those that are artificially synthesized, such as polyethylene glycol, polylactic acid, and polycaprolactone. These polymers can degrade via hydrolytic and enzymatic processes in the body into low-molecular-weight products that are then reabsorbed or excreted, making them the most suitable materials for the synthesis of biodegradable nanoparticles. Biodegradable polymers can react with other substances to form nanocomposites, which have superior biocompatibility, degradability, and safety. Biodegradable polymer-based nanocomposites exhibit targeting capabilities, including passive (enhanced permeability and retention effect), active (ligand-receptor interactions), tumor microenvironment-responsive, and external stimulus-responsive (e.g., magnetic, electric, and lightdriven) targeting. In addition, synthesized biodegradable nanomaterials can alter the solubility of the loaded drug and improve its bioavailability. Thus, these materials have been widely used in drug delivery systems. This review aimed to summarize the recent advances in biodegradable polymeric nanomaterials for biomedical drug delivery, analyze their design advantages and clinical translation potential, and explore their future prospects and challenges in precision therapy and targeted delivery.