Ultrasensitive Detection and Cellular Photothermal Therapy via a Self‐Photothermal Modulation Biosensor

Abstract

The use of light, which is s a powerful tool for imaging and sensing, has also become one of the most prospective strategies in tumor treatment. Optical microfibers, which have engineerable waveguiding properties, are highly attractive for optical sensing and photothermal therapy on the micro/nanoscale. However, for their real‐world application, the sensitivity limit needs to be addressed, as does the issue of improving the intrinsic photothermal performance of silica microfibers. Herein, a nanointerface consisting of triangular Au@Ag2S nanoplates and VO2 nanoparticles on an optical microfiber is designed to fabricate a structurally resilient hierarchical microfiber sensor with well‐distributed plasmonic hotspot enhancement. The nanointerface enhances the evanescent field with temperature tunability, adding a self‐photothermal modulation function to the sensor. The sensor exhibits a temperature‐tunable sensitivity to alpha‐fetoprotein with a limit of detection of 0.62 × 10−18 m. It differentiates hepatoma carcinoma cells from normal cells and provides photothermal therapy aimed at the former. Quantitative evaluation of the sensor indicates that photothermal therapy kills more than 82% of cancer cells using a lower power. This work provides a new opportunity for selective evanescent field modulation for evanescent biosensors as well as a potential approach to the integration of cellular diagnosis and therapy.

Optical microfiber or nanofiber: a miniature fiber-optic platform for nanophotonics

“…Later in 2019, Zhou et al demonstrated a gold-nanorod-MNF coupled system for relative humidity sensing, and achieved a spatial resolution of 1.5 mm [414] . Meanwhile, such photon-plasmon coupled MNF systems have also served as an effective platform for biosensing [441,511,512] . For example, in 2019 Li et al functionalized the surface of a 7.1μm-diameter MNF with a plasmonic nanointerface consisting of black-phosphorus-supported gold nanohybrids [510] .…”

“…demonstrated a gold-nanorod-MNF coupled system for relative humidity sensing, and achieved a spatial resolution of 1.5 mm [414] . Meanwhile, such photon-plasmon coupled MNF systems have also served as an effective platform for biosensing [441,511,512] . For example, in 2019 Li et al .…”

Recent advances in photothermal nanomaterials-mediated detection of circulating tumor cells

“…Xiao et al designed a silicon dioxide microfiber combined with Au@Ag 2 S nanomaterials, which enhanced the sensitivity of the sensor to temperature and was able to distinguish hepatocellular carcinoma cells from normal cells and kill the cancerous cells by photothermal heat. 88 Yin et al used mesoporous silica as an intermediate layer and ferric iron tetroxide as the core, and CdTeS quantum dots as fluorescent labeling agent, which can detect and destroy cancer cells more perfectly. 89 Of course the coupling of silica and gold nanomaterials is very common, Seo et al synthesized GNR@SiO 2 nanoparticles to enhance their near-infrared light absorption.…”