Poly(lactic-co-glycolic acid) (PLGA) is a functional polymer organic compound randomly polymerized by lactic acid (PLA) and glycolic acid (PGA). It has been approved by the U.S. Food and Drug Administration It is certified by the Food and Drug Administration (FDA) and is a copolymer material available on the market. PLGA has good biocompatibility, biodegradability, mechanical strength, good plasticity, surface modification, and drug encapsulation. It has a wide range of uses in the field of biomedical engineering and has been used in drug sustained-release carriers, artificial catheters and tissue engineering scaffold materials.

As a drug carrier, PLGA is soluble in common solvents such as acetone and ethyl acetate. The size, shape and surface area of PLGA nanoparticles can be adjusted by adjusting the molecular weight and ratio of lactic acid and glycolic acid in the polymer to obtain the required nanocarriers are simultaneously processed and prepared into various shapes and sizes. Currently, PLGA nanoparticles can be prepared based on emulsion solution volatilization or co-precipitation technology. The most common methods include simple mechanical stirring, ultrasonic treatment, high shear mixing (HSM), high pressure homogenization (HPH) and microfluidics. Depending on the preparation methods of PLGA nanoparticles, amphiphilic, hydrophobic or hydrophilic drug molecules can be loaded into the core area of the nanoparticles or adsorbed on the surface of the nanoparticles, which can effectively deliver drugs.

Compared with other carrier materials, PLGA nanocarriers have the following advantages:

• It is polymerized by glycolic acid and lactic acid, and the synthesis process is relatively mature;
• The nanoparticle size is controllable, uniform in size and small in dispersion;
• It can achieve long-term sustained release of carrier drugs (several weeks or months), reduce the frequency of medication, and greatly improve patient compliance;
• Modified PLGA nanoparticles can contain biologically active molecules such as proteins, genetic DNA, and vaccines;
• After the PLGA surface is chemically modified with ligands, precise targeted delivery of drugs can be achieved.

Functional modulation or modification of PLGA nanoparticles is of great significance for the treatment and application of diseases, such as active targeted therapy of drugs or diagnosis of diseases. In drug delivery, in order to accurately reach the lesion site with the appropriate amount of drugs and achieve targeted therapy, proteins, polysaccharides, peptides, or small molecules can usually be formulated on the PLGA carrier through certain chemical coupling or physical cross-linking methods. The body is modified on the surface of PLGA nanoparticles to achieve active targeted delivery to the lesion, improve the therapeutic effect and biological safety of the drug, and reduce the toxic and side effects of the drug on other normal tissue cells. For example, Tween 80, also known as polysorbate 80, can be used as a surfactant in the preparation of PLGA nanoparticles, and it can also adsorb apolipoprotein E to the surface of PLGA nanoparticles. Promote the binding of nanoparticles to lipoprotein receptor-related protein (LRP), thereby effectively promoting the nanoparticles to cross the blood-brain barrier (BBB), which has potential application value in the treatment of brain diseases. The particle size of PLGA nanoparticles is controllable, uniform in size, and has low dispersion. Therefore, it can be well modified on its surface, such as coating with cell membrane, for the design and development of tumor vaccines. CpG is a type of oligodeoxynucleotide that can be used as an immune adjuvant to stimulate the maturation and development of antigen-presenting cells. CpG can be encapsulated with PLGA using the emulsion evaporation method. The tumor cell membrane expresses a large number of tumor-related antigens, so the cell membrane can be used as an antigen to stimulate the body’s immune response. The tumor cell membrane is coated with PLGA nanoparticles, and a nanovaccine based on PLGA as the core is constructed, which can be used to fight melanoma B16 of immunotherapy.