In order to achieve real-time and in situ detection of endotoxin, which is an important and significant clinical test index, surface-enhanced Raman spectroscopy (SERS) chip integrated array microchambers within bioscaffold nanostructures and a SERS monitoring strategy were proposed in this paper. After sputtering of nanogold on the cicada wing, which was selected as a natural template, and polydimethylsiloxane bonding, array-type chambers within bioscaffold nanostructures were prepared for in situ bacterial culture and monitoring of endotoxin in the bacteriostasis process by SERS. Meanwhile, the SERS tag modified with the DNA aptamer was prepared and added into this complex biochemical reaction to further improve the sensitivity and selectivity. A new method for in situ detection of endotoxin was thus established. The detection time was shortened to 100 s, and the detection limit was as low as 6.25 ng/mL. Pseudomonas aeruginosa was cultured in situ in the chamber of the SERS chip with antimicrobial agents in 0-72 h. The endotoxin released in the antibacterial process was monitored by the designed SERS detection strategy. The results obtained by SERS analysis were consistent with those of the ELISA kit.
Keywords: SERS tag; bacteriostatic process; biochip; endotoxin; in situ detection.