Fig. 8.

A Illustration of the E. coli-DTTC-Cu₃SnS₄. B The SEM and EDS element mapping of the E. coli-DTTC-Cu₃SnS₄. C The Raman spectra of E. coli-DTTC and E. coli-DTTC-Cu₃SnS₄. D The UV/Vis/NIR absorption spectrum of the E. coli-DTTC-Cu₃SnS₄. E In vitro SERS spectra of E. coli-DTTC-Cu₃SnS₄ under the excitation of a 785 nm laser. F Raman peak intensity versus Log E. coli-DTTC-Cu₃SnS₄ concentration at 507 cm⁻¹