Rationally Engineered Photonic-Plasmonic Synergistic Resonators in Second Near-Infrared Window for in Vivo Photoelectrochemical Biodetection.

The introduction of photonic technologies into biodetection fields is in high demand to accelerate understanding vital movements at the molecular level. Great difficulty lies in the fact that the short penetration of photons in biotissues limits the practical applications of in vivo biodetection. Herein, we overcome this long-standing technical challenge through first introducing a new synergistic photonic-plasmonic resonator in second near-infrared window to realize efficient light trapping in this "bio-transparent zone". The well-match of photonic and plasmonic resonances in the same wavelength significantly increases the light-matter interplay activity, with 60% increase of quality factors, thus allowing us to pioneeringly implement the sensitive photoelectrochemical in vivo biodetection of macrophage cells in the tail vein of a living mouse. These synergistic photonic-plasmonic resonators promise bridges between vital photonic phenomena and practical biodetections or clinical applications.