“Afterglow” Photodynamic Therapy Based on Carbon Dots Embedded Silica Nanoparticles for Nondestructive Teeth Whitening

Abstract

Teeth staining is a common dental health challenge in many parts of the world. Traditional teeth whitening techniques often lead to enamel damage and soft tissue toxicity due to the use of bioincompatible whitening reagents and continuous strong light irradiation. Herein, an "afterglow" photodynamic therapy (aPDT) for teeth whitening is proposed, which is realized by energy transition pathways of intersystem crossing. The covalent and hydrogen bonds formed by carbon dots embedded in silica nanoparticles (CDs@SiO2) facilitate the passage of energy through intersystem crossing (ISC), thereby extending the half-life of reactive oxygen species (ROS). The degradation efficiency of aPDT on dyes was higher than 95% in all cases. It can thoroughly whiten teeth by eliminating stains deep in the enamel without damaging the enamel structure and causing any tissue toxicity. This study illustrates the superiority of aPDT for dental whitening and the approach to exploring carbon-dots-based nanostructures in the treatment of oral diseases.

Photo-Driven In Situ Solidification of Whole Cells through Inhibition of Trogocytosis for Immunotherapy

“…Tumor cells can be pretreated for better efficacy, such as the ability to genetically engineer the expression of specific antigens [ 11 , 12 ]. In situ tumor vaccines are based on a certain type of stimulated immune response to achieve a tumor immunotherapeutic effect and they can be obtained through in situ photothermal treatment of tumor tissues, photodynamic therapy, chemotherapy, radiotherapy, or sonodynamic therapy [ 13 – 16 ]. However, inactivated whole-cell tumor vaccines carry a high risk of causing recurrent cytokine storms or even unexpected Schwarzman reactions when administered multiple times to achieve antitumor effects.…”

Recent advances in fluorescence and afterglow of CDs in matrices

“…Carbon dots (CDs) have been shown to possess great potential for applications in optoelectronics, 1–3 sensing, 4,5 information security, 6 and biology 7,8 due to their nontoxicity, low cost, superior optical properties and biocompatibility. The optical properties of CDs in solution have been extensively studied and improved.…”

Photoinduced absorption and linear/nonlinear emission of assembled carbon dot–silica nanocomposites for cellular imaging

“…Carbon dots (CDs) have a size below 10 nm and belong to a new class of carbon nanomaterials, which have attracted considerable attention since they were first found in 2004. 1 CDs are advantageous in biological applications including bio-imaging in vitro and in vivo , 2–4 cancer diagnosis and biotherapy, 5–8 and gene/drug delivery and bio-sensing 4,8–10 due to their excellent properties of bright-light emission and wide-emitting range, facile preparation process, low/no toxicity, cheap source, etc. 8,11–13 The most widely investigated photoluminescence property for CD-based nanomaterials is the common fluorescence, that is the one-photon excited fluorescence (1PEF).…”