Disulfide-bridged cleavable PEGylation in polymeric nanomedicine for controlled therapeutic delivery.

PEGylation in polymeric nanomedicine has gained substantial predominance in biomedical applications due to its resistance to protein absorption, which is critically important for a therapeutic delivery system in blood circulation. The shielding layer of PEGylation, however, creates significant steric hindrance that negatively impacts cellular uptake and intracellular distribution at the target site. This unexpected effect compromises the biological efficacy of the encapsulated payload. To address this issue, one of the key strategies is to tether the disulfide bond to PEG for constructing a disulfide-bridged cleavable PEGylation. The reversible disulfide bond can be cleaved to enable selective PEG detachment. This article provides an overview on the strategy, method and progress of PEGylation nanosystem with the cleavable disulfide bond.