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Updated: Feb 11, 2026

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by π-π Stacking Interactions
Published on: October 10, 2016
Photoinduced PEG deshielding from ROS-sensitive linkage-bridged block copolymer-based nanocarriers for on-demand drug
Jie Li1, Chunyang Sun2, Wei Tao1
1School of Biological and Medical Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China.
Abstract:
Controlling poly(ethylene glycol) (PEG) shielding/deshielding at the desired site of action exhibits great advantages for nanocarrier-based on-demand drug delivery in vivo. However, the current PEG deshielding strategies were mainly designed for anticancer drug delivery; even so, their applications are also limited by tumor heterogeneity. As a proof-of-concept, we explored a photoinduced PEG deshielding nanocarrier TK-NPCe6&PTX to circumvent the aforementioned challenge. The TK-NPCe6&PTX encapsulating chlorin e6 (Ce6) and paclitaxel (PTX) was self-assembled from an innovative thioketal (TK) linkage-bridged diblock copolymer of PEG with poly(d,l-lactic acid) (PEG-TK-PLA). We demonstrated that the high PEGylation of TK-NPCe6&PTX in blood helps the nanocarrier efficiently avoid rapid clearance and consequently prolongs its circulation time. At the desired site (tumor), 660-nm red light irradiation led to ROS generation in situ, which readily cleaved the TK linkage, resulting in PEG deshielding. Such photoinduced PEG deshielding at the desired site significantly enhances the cellular uptake of the nanocarriers, achieving on-demand drug delivery and superior therapeutic efficacy. More importantly, this strategy of photoinducing PEG deshielding of nanocarriers could potentially extend to a variety of therapeutic agents beyond anticancer drugs for on-demand delivery.
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