Barhoumi A, Salvador-Culla B, Kohane D. NIR-Triggered Drug Delivery by Collagen-Mediated Second Harmonic Generation.. Adv Healthc Mater. 2015;4(8):1159–63.
Abstract
Second harmonic generation is a process through which nonlinear materials such as collagen can absorb two photons and scatter one with twice the energy. Collagen upconverts 730 nm (near-IR) to 365 nm (UV) through second harmonic generation, which cleaves a molecule bound to collagen via a UV-sensitive linker.