Currently, in the research of nanoscale drug delivery systems, there are several problems such as poor biocompatibility, short blood circulation lifespan, insufficient active targeting, and low permeability through biological membranes. Particularly in the bloodstream, a large amount of non-specific proteins and biomolecules adsorb on the surface of nano-carriers forming a protein corona layer, which greatly affects the expected therapeutic efficacy of the nano-carriers reaching the targeted site as designed. Therefore, based on the new biomimetic drug delivery systems of various cells in the body's circulatory system, it has gradually become a research hotspot in the field of life sciences in recent years. Among them, platelets and their membrane biomimetic drug delivery system have attracted great attention from researchers. As an inherent component of the body, platelets can escape the immune system clearance and are closely related to physiological processes such as endothelial injury repair, immune response, atherosclerosis formation, neurodegeneration, and tumor growth and metastasis. Platelets can target and accumulate well in the reactive sites of these body responses. Therefore, the platelet membrane biomimetic drug delivery system shows great potential for application in tumor targeting, endothelial injury repair, and coagulation, etc.
According to the drug loading method and assembly method, platelets and their membrane biomimetic drug delivery system can be divided into three categories: carrier with drugs covalently linked to the platelet membrane, carrier with drugs directly loaded into platelets, and nano-carrier coated with platelet membrane.
The carrier with drugs covalently linked to the platelet membrane is a delivery carrier that uses natural platelets as a medium to chemically covalently link or express drugs on the platelet membrane through biological engineering means. It utilizes the platelet's targeting binding ability in tumor tissues, circulating tumor cells (CTCs), damaged blood vessels and other sites to deliver drugs to the lesion. Then the platelets are activated and release drug-containing microparticles to exert a therapeutic effect.
The carrier with drugs directly loaded into platelets is a delivery carrier that uses various means such as chemical methods, electroporation, phagocytosis, low-permeation, and lipid fusion to load drugs into natural platelets. The protection of natural platelets can improve drug stability, reduce adverse reactions, and enhance therapeutic effects.
The nano-carrier coated with platelet membrane is a functional delivery carrier that coats the platelet membrane on the surface of the nano-carrier through electrostatic adsorption and can further modify its membrane surface. Platelets extracted from fresh blood can still retain platelet membrane proteins well after processes such as separation, purification, freeze-thaw or lytic expansion, centrifugation, etc., and exhibit their original physiological characteristics after being coated on the surface of the nano-carrier. This type of drug delivery system provides a layer of biological camouflage outerwear for the nano-carrier, while improving biocompatibility and immune escape ability, it can also use the free amino or carboxyl groups on the platelet membrane for chemical modification and endow the carrier system with more diverse functions.
The Application of Platelet Membrane Biomimetic Carriers
1. Application of Platelet Membrane Biomimetic Nanocarriers in Targeted Cancer Therapy
Platelet membrane expresses various proteins (such as selectins and integrins) that can bind to receptors on tumor cells. Therefore, platelet membrane biomimetic carriers have tumor targeting properties and can be used for targeted cancer therapy. Firstly, platelet membrane biomimetic nanocarriers enhance the efficacy of conventional chemotherapy drugs. For example, platelet membrane-coated silica nanoparticles can deliver TRAIL (Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand) to tumor blood vessels to kill tumor cells. By retaining the complete composition of me...
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