High-performance detection of endotoxin by the microfluidic chip integrated with surface acoustic wave sensor modified by Ti(3)C(2)Tx/Au NPs nanocomposite

To detect endotoxin rapidly and sensitively, a sandwich surface acoustic wave (SAW) sensing strategy based on the sensing interface Ti3C2Tx/Au NPs/Apt1/MCH and the nanoprobe Au NPs/Apt2/mPEG was proposed. In addition, a microfluidic chip integrated with functional parts of derivatization, capture, enrichment, and detection was designed and fabricated. The sensing interface was designed to improve the acoustic properties of the SAW sensor and capture the target. The nanoprobe was prepared and applied for specific endotoxin binding and phase signal amplification. It was illustrated that the sensitivity for the on-chip detection of endotoxin was improved and the detection limit was reduced by one order of magnitude by using the newly-constructed sensing strategy. Moreover, the endotoxin conjugate was concentrated in a continuous flow mode on the sensing interface of the SAW sensor, and the secondary amplification of the phase signal was achieved, which was approximately 1.5 times higher than that obtained in the static mode. A novel in situ quantitative detection strategy for endotoxin was thus established, and it was applied to measure endotoxin in real serum samples with a detection limit of 0.05 ng/mL and a linear range between 0.05 and 10 ng/mL.