Engineered photo-responsive materials for near-infrared-triggered drug delivery

Near-infrared (NIR) light-responsive drug delivery systems have gained increasing interest in biomedical applications due to their spatiotemporal and on-demand drug release. This review summarizes recent progress in development of various photo-responsive materials for NIR light-triggered drug release, with particular emphasis on their molecular designs and formulations as well as photo-reaction mechanisms. Various NIR light-responsive materials have been developed mainly by incorporating NIR light-responsive photochromic moieties. The photo-reaction mechanisms of NIR light-responsive materials for NIR light-triggered drug release include photo-induced transition of hydrophobicity-hydrophilicity, photo-cleavage reaction, and photo-induced heating, which induce disruption of the drug carriers for drug release. This review also highlights an emerging technology of utilizing upconverting nanoparticles (UCNPs) to significantly enhance the NIR light-sensitivity of the currently developed photo-responsive drug carriers. This review demonstrates that NIR-responsive drug delivery systems capable of spatiotemporal and on-demand drug release are highly desired to translate the promise of drug delivery for clinical therapy. (C) 2015 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.