Near‐Infrared Light‐Triggered Chlorine Radical (^.Cl) Stress for Cancer Therapy

Abstract

Free radicals with reactive chemical properties can fight tumors without causing drug resistance. Reactive oxygen species (ROS) has been widely used for cancer treatment, but regrettably, the common O2 and H2O2 deficiency in tumors sets a severe barrier for sufficient ROS production, leading to unsatisfactory anticancer outcomes. Here, we construct a chlorine radical (.Cl) nano‐generator with SiO2‐coated upconversion nanoparticles (UCNPs) on the inside and Ag0/AgCl hetero‐dots on the outside. Upon near‐infrared (NIR) light irradiation, the short‐wavelength emission UCNP catalyzes .Cl generation from Ag0/AgCl with no dependence on O2/H2O2. .Cl with strong oxidizing capacity and nucleophilicity can attack biomolecules in cancer cells more effectively than ROS. This .Cl stress treatment will no doubt broaden the family of oxidative stress‐induced antitumor strategies by using non‐oxygen free radicals, which is significant in the development of new anticancer agents.

Recent near-infrared light-activated nanomedicine toward precision cancer therapy

“…As a novel ingredient of NPDT, UCNPs extended the PDT from the UV/Vis to the NIR window in their own way, which provided an enormous stage for ROS-generation. 115 For example, visual-light triggered cyclometalated iridium(III) complexes with excellent photophysical properties were found as potent PS candidates, 116 and UCNPs endowed the complexes with NIR activation features and realized an NPDT with higher biosafety and 1 O 2 generation efficiency (Fig. 5A).…”

Boosting the Energy Migration Upconversion through Inter-Shell Energy Transfer in Tb 3+ -Doped Sandwich Structured Nanocrystals

“…Nevertheless, the ultraviolet excitation of Tb 3+ complex inevitably causes the issues of poor tissue penetration of excitation light and background biofluorescence from endogenous chromophores and proteins for in vivo biodetection. [19][20][21][22][23][24][25][26] Unfortunately, even if substituting the luminescent Tb 3+ complex with the EMU NCs (e.g., NaGdF 4 :Yb/Tm@NaGdF 4 :Tb) that are excitable by 980 nm NIR light can help in the light penetration depth, [27][28][29][30] the issue of background biofluorescence induced by the ultraviolet upconversion emissions of Tm 3+ will still exist. This is because that the Tm 3+ ultraviolet emissions of considerable magnitude were always concomitant with the 5 D 4 → 7 F J emissions of Tb 3+ for the previously reported Tb 3+ -doped EMU NCs.…”

Photon upconversion through triplet exciton-mediated energy relay

“…Optical spectroscopy has witnessed a rapid development of lanthanide-doped nanoparticle probes over the past decade owing to their outstanding features, including sharp emission bandwidths, large anti-Stokes shifts, and high photostability, as well as the ability to convert near-infrared (NIR) excitation to short-wavelength emission 1 – 4 . These nanoparticles hold great promise in optical imaging 5 – 9 , sensing 10 – 14 , optogenetics 15 – 17 , lasing 18 , 19 , anticounterfeiting 20 , 21 , volumetric display 22 , and therapeutics 23 – 26 . Despite enticing prospects, photon upconversion has been largely limited to a small set of lanthanide activators (e.g., Er 3+ , Tm 3+ , and Ho 3+ ) with ladder-like energy levels 27 – 32 .…”