Sensitively detecting mTBI biomarker S100B by using peptide-modified ratiometric fluorescent C/AuNCs nanoprobe.

Mild traumatic brain injury (mTBI) has become a tough nut in forensic science because of its minor damages but serious consequences. Utilizing biomarkers to diagnose mTBI has become a promising approach due to various shortcomings of traditional diagnostic methods. In this work, we developed a peptide-modified ratiometric fluorescent nanoprobe based on carbon dots (CDs) and gold nanoclusters (AuNCs) for the measurements of a pivotal biomarker S100B protein in the early diagnosis of mTBI. It has been found that florescence intensity of AuNCs at 580 nm was decreased as report signal while the florescence intensity of CDs was unchanged as reference signal in this sensing system when the surface modified peptide bind tightly with calcium-activated S100B. Under the optimized conditions, S100B concentration ranging from 0.03 to 1 μg/mL was successfully determined within 30 min, and the detection limit of 0.01 μg/mL was acquired through the standard rule (S/N = 3). Moreover, the detection of S100B in spiked blood samples were conducted with satisfactory recoveries. The as-prepared ratiometric fluorescent nanoprobe was proved to be a time-saving, convenient, and sensitive strategy, and it showed great prospects in the early diagnosis of mTBI in forensic practice.