@article {203159,
	title = {Plasmonic and Electrostatic Interactions Enable Uniformly Enhanced Liquid Bacterial Surface-Enhanced Raman Scattering (SERS).},
	journal = {Nano letters},
	volume = {20},
	year = {2020},
	pages = {7655-7661},
	abstract = {<p>Surface-enhanced Raman spectroscopy (SERS) is a promising cellular identification and drug susceptibility testing platform, provided it can be performed in a controlled liquid environment that maintains cell viability. We investigate bacterial liquid-SERS, studying plasmonic and electrostatic interactions between gold nanorods and bacteria that enable uniformly enhanced SERS. We synthesize five nanorod sizes with longitudinal plasmon resonances ranging from 670 to 860 nm and characterize SERS signatures of Gram-negative  and  and Gram-positive  and  bacteria in water. Varying the concentration of bacteria and nanorods, we achieve large-area SERS enhancement that is independent of nanorod resonance and bacteria type; however, bacteria with higher surface charge density exhibit significantly higher SERS signal. Using cryo-electron microscopy and zeta potential measurements, we show that the higher signal results from attraction between positively charged nanorods and negatively charged bacteria. Our robust liquid-SERS measurements provide a foundation for bacterial identification and drug testing in biological fluids.</p>
},
	author = {Tadesse, Loza F and Ho, Chi-Sing and Chen, Dong-Hua and Arami, Hamed and Banaei, Niaz and Gambhir, Sanjiv S and Jeffrey, Stefanie S and Amr A. E. Saleh and Dionne, Jennifer}
}
