Fig. 19. (A) Schematic of the application of AuNC–hyaluronic acid (HA)–protein protamine (PROT) nanocomposites with enhanced emission and ROS generation through a self-assembly approach. (B) FRET-based two-photon excited theranostic nanoplatform using Au NCs attached to GQD for two-photon imaging and two-photon induced PDT killing of MDRB. ¹O₂ emissions under two-photon excitation at ∼1270 nm from the nanoplatform. (C) UV-vis absorption spectrum (black) and emission spectrum (red) of Tm³⁺-activated up-conversion NPs (UCNPs)@g-C₃N₄–Au₂₅–PEG upon 980 nm NIR laser excitation, and schematic of the ROS generation mechanism. Panel (a) is reproduced with permission from ref. 106. Copyright 2019 American Chemical Society. Panel (b) is reproduced with permission from ref. 115. Copyright 2018 American Chemical Society. Panel (c) is reproduced with permission from ref. 118. Copyright 2017 American Chemical Society.