Metal-respiring bacteria are frequently used to recycle metal resources by biosynthesizing nanoparticles on its surface in environment treatment. However, further utilization of biogenetic nanoparticles through combining the advantages of both bacteria and nanoparticles is still limited. Herein, biogenetic Au@Ag nanoislands are utilized as the surface-enhanced Raman spectroscopy (SERS) substrate for quantitative detection. Specifically, Au@Ag nanoislands enhance the Raman signal via surface plasmon resonance, while biomolecules (phospholipid, tyrosine, and phenylalanine, etc.) on bacterium serve as an internal standard to eliminate the discrepancy of the target SERS intensity in different hot spots. Gene-controlled biomolecules in bacteria guarantee the reproducibility of this SERS substrate. The generality of this analytical method is demonstrated by determining rhodamine 6G, malachite green, and uric acid. This discovery solves a pervasive problem in SERS analysis through a simple biogenetic nanosystem, which opens up an avenue to address scientific challenges by using versatile organisms from nature.
Keywords: SERS; internal standard; microbial synthesis; noble metals; quantitative detection.