Upconversion Nanoparticle-Induced Multimode Photodynamic Therapy Based on a Metal–Organic Framework/Titanium Dioxide Nanocomposite

Abstract

Photodynamic therapy (PDT) possesses two pathways depending on the type of high-toxicity reactive oxygen species (ROS), superoxide anion radical (O 2•− ) and hydroxyl radical ( • OH) generated through Type I and singlet oxygen ( 1 O 2 ) generated through Type II, inducing cancer cell apoptosis. However, the low efficiency of ROS generation and poor biocompatibility are the limitations of the traditional photosensitizers for PDT. Herein, inspired by photochemical reactions of titanium dioxide and porphyrin-based metal− organic frameworks, we developed a nanoplatform by covering ultrasmall titanium dioxide nanoparticles on a heterodimer made up of upconversion nanoparticles and metal−organic frameworks, realizing a multimode PDT through Type I and Type II mechanisms. Once irradiated by a near-infrared light, upconversion nanoparticles could generate ultraviolet and visible lights, which were not only able to stimulate different photochemical reactions of titanium dioxide and porphyrin but also accomplish deep penetration photodynamic therapy. Our photosensitive agent exhibited good biocompatibility and an effective multimode PDT performance, which could meet the needs of different situations of photodynamic therapy in the future.

RETRACTED: Autophagy regulates the Wnt/GSK3β/β-catenin/cyclin D1 pathway in mesenchymal stem cells (MSCs) exposed to titanium dioxide nanoparticles (TiO2NPs)

“…Despite the potentially harmful consequences of autophagy, the autophagic response induced by TiO 2 NPs may be implicated usefully in medical applications. For example, in recent years, the photocatalytic effects of TiO 2 NPs have facilitated its application in photodynamic therapy [ [42] , [43] , [44] ].…”

“…Specifically, Cheng et al [ 42 ] demonstrated that the photocatalytic properties of TiO 2 -based composite nanoparticles could induce severe toxicity and cell death in melanoma cells. Similarly, Shi et al [ 44 ] showed that TiO 2 -based metal-organic frameworks induced apoptotic cell death in cancer cells by producing ROS under UV-irradiation. It is generally acknowledged that the photo-response of TiO 2 NPs is limited to UV-irradiation due to its wide bandgap, which, on the other hand, gifts this material with excellent ROS production abilities during its application in anti-cancer therapies [ 43 ].…”

Metal‐Organic Frameworks‐Based Fluorescent Nanocomposites for Bioimaging in Living Cells and in vivo†

“…Recently, Yang and co‐workers developed a nanoplatform consisting of UCNPs and (TCPP)‐MOF, which further coated with ultrasmall TiO 2 nanoparticles, realizing a multimode PDT. [ 106 ] The combination of UCNPs and TiO 2 could achieve deep biological tissue penetration capacity beneficial fo r in vivo imaging and PDT. CLSM images of the MCF‐7 cells demonstrated that UMOF‐TiO 2 exhibited good ROS generation ability to meet the potential needs of PDT.…”

Recent Advances on Rare Earth Upconversion Nanomaterials for Combined Tumor Near-Infrared Photoimmunotherapy

“…First, optimizing energy utilization rate of UCNPs can not only reduce the toxicity from dosage, but also improve the therapeutic effect of nanoparticles. UCNPs are usually combined with PS to produce ROS (He et al, 2017 ; Shi et al, 2020 ). However, most PSs can only absorb single emission light by UCNPs with low energy utilization rate.…”