TABLE 1

Summary of the characteristics of different categories of linker

CategoriesExamplesCharacteristics
Cleavable linkersAcid-sensitive or acid-labile linkersCapable of being cleaved by environmental differences (such as redox potential, pH value) and specific lysosomal enzymes;
High stability, targeted release of payload;
Bystander killing effect.
Lysosomal protease-sensitive linkers
β-Glucuronic acid linker
Glutathione-sensitive disulfide linkers
Noncleavable linkersThioethersHigher stability and resistance to proteolytic enzyme degradation;
Higher safety, longer plasma half-life, and lower risk of off target;
High internalization efficiency and promotion of lysosomal function to a certain extent.
Maleimidocaproyl group
GMBS
SMCC
  • GMBS, N-(γ-maleic imide butyl acyl oxygen) succinamide ester; SMCC, succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate.