TABLE 1.

Summary of the assigned peaks in the SERS spectra.

Biomolecules	Peak assignment (cm– 1)	Tentative assignment	References
Carbohydrates	492, 472, 491, 414, 486, 489	Skeletal mode of C-C	Chao and Zhang, 2012
	569, 544	C-O-C glycosidic deformation	Chao and Zhang, 2012
	1041, 1026, 1069, 1058	C-O, C-C stretching	Efeoglu and Culha, 2013
Nucleic acid	776, 785	O-P-O stretching of DNA	Wickramasinghe et al., 2020
	1585	Guanine	Chen et al., 2015
	730	Adenine from flavin	Chao and Zhang, 2012
	1346	Guanine
Proteins	838	Amide group, deformation vibration	Xie et al., 2013
	1350	Amide II	Henry et al., 2017
	673	C-C stretching tyrosine	Chao and Zhang, 2012
	1028	C-H bending of protein	Ogawa et al., 2020
	869	Single bond stretching vibration of proline and valine	Valle et al., 2008; Goh et al., 2013
	1220–1240	Amide III (arising from coupling of C–N stretching and N–H bonding)	Samek et al., 2008; Chao and Zhang, 2012
	1324	Tyrosine	Xie et al., 2013
	657, 678	C-S stretching and C-C twisting of proline and tyrosine	Efeoglu and Culha, 2013
	852	Ring breathing structure of Tyrosine	Wickramasinghe et al., 2020
	1490	Amide II
	1596	Amide, Tyrosine	Xie et al., 2013
	1705	Amide I, βsheets	Chen et al., 2015
Lipids	1448, 1452	Deformation vibration of CH2 scissoring	Samek et al., 2014
	980	C-C stretching	Samek et al., 2008
	1148	Fatty acids	Ogawa et al., 2020
	1179	C-C stretching vibration	Ogawa et al., 2020