Bulk/Surface Defects Engineered TiO2 Nanotube Photonic Crystals Coupled with Plasmonic Gold Nanoparticles for Effective in Vivo Near-Infrared Light Photoelectrochemical Detection.

Photoelectrochemical (PEC) techniques are of fundamental and practical importance, and they have been widely used for solar energy conversion and experimental protection. Besides these important applications, an emerging and fast developing PEC application of PEC bioanalysis is receiving more attention from both academic and clinic communities. However, the typical PEC biosensing is still limited under illumination of ultraviolet and visible (UV/vis) light, which hampers its in vivo detection in deep tissues. Expanding the optical absorption wavelength of photoelectrodes from the UV/vis light region into the near-infrared (NIR) light region is highly desirable due to its deep tissue penetrability and minimal invasiveness for organisms, but the exploration of a facile strategy to implement efficient NIR absorption with biocompatible materials is still a big challenge. Herein, under the guidance of theorical calculations, we propose a strategy through modulation of bulk/surface defects and decoration of Au nanoparticles on TiO2 nanotube photonic crystals to implement efficient NIR response and thus successfully realize sensitive and selective PEC detection of antibiotics in real bio- and experimental-samples under NIR illumination. In addition, we first implement the in vivo PEC detection under illumination of NIR light. We have faith that this new NIR photoelectric responsive strategy will provide a broad platform for detection of life-related biomolecules in deep tissues or even in vivo for real-time measurement and shed light on the intrinsic connections between biomarkers and clinical diseases.