Liposome bioconjugates refer to a class of bioconjugates formed by modifying the surface of liposomes by coupling with polypeptides, proteins, and small molecular substances. Liposome bioconjugates have shown strong application potential in many fields, among which, the delivery vehicles of targeted drugs, vaccines and biological macromolecules are the most important applications. In addition, liposome bioconjugates can also be used in the fields of disease diagnosis and treatment, as well as the research on the activity and function of biological macromolecules.
As a leading service provider, BOC Sciences offers comprehensive liposome bioconjugation services that can be custom designed and developed to fit your needs. Our professional team can support the development of the following liposome conjugates:
With the help of linkers and different conjugation methods, drug moieties can be conjugated to liposomes to enhance targeted delivery, enhance drug loading, or reduce toxicity. Drugs conjugated to the phospholipids of the liposomes are covalently or non-covalently linked to phosphate groups or to the glycerol backbone. Hydrophilic payloads can be converted into water-soluble lipid conjugates to improve their solubility in lipids. Factors affecting the synthesis of drug-liposome conjugates include selection of lipids containing the desired functionality to accommodate covalent or non-covalent linkage. Recently, the use of ester bonds, disulfide bonds, hydrazone bonds and other covalent bonds to generate drug-liposome conjugates has been intensively studied.
Surface attachment of antibodies to liposomes is a common method for the production of actively targeted drug delivery systems. This liposome formulation can efficiently target the antibody-liposome bioconjugate to its matched antigen. Once the immunoliposome is docked at the antigenic site, it can deliver its drug payload, thereby minimizing off-target effects of the drug. This process is typically accomplished by using N-hydroxysuccinimide (NHS) to activate the thiol-maleimide reaction, which in turn attaches antibody fragments to the surface of PEGylated liposomes.
Aptamers are single-stranded, short DNA or RNA oligonucleotides with the advantages of versatility, high affinity to a single target, small size, stability, low immunogenicity, and ease of synthetic preparation. Typically, aptamers are attached to liposomes using covalent bonds or post-insertion methods. Covalent bonding techniques typically employ 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) chemistry and a thiol-maleimide bonding reaction. The post-insertion approach reacts functional group-activated lipids with aptamers to form labile micelles, which are then mixed with preformed liposomes to incorporate the aptamer-lipid into the liposome membrane.
Covalent bonds (such as peptide bonds, sulfonyl bonds, disulfide bonds and thioester bonds, etc.) as well as non-covalent bonds are widely used in the construction of engineered liposome-peptide conjugates. Peptides mainly refer to two types, namely cell-penetrating peptides and cell-targeting peptides. The former has non-specific binding, while the latter has receptor-specific binding and internalization capabilities. Liposome-peptide conjugates exhibit good tumor penetration and efficient drug delivery properties.
The cell coat usually contains a high proportion of polysaccharides. Therefore, taking advantage of this feature, coupling drug-loaded liposomes with carbohydrates into microparticles can not only improve the cell targeting specificity in vivo, but also prevent the pressure changes caused by the biological environment and inhibit the degradation of biologically sensitive substances. The carbohydrates used to modify liposomes include: galactose, chitosan, mannose, amylose and dextran. Since some polysaccharides themselves have biological effects, they are more targeting once they are in the form of conjugates.