Improving SERS Detection of Bacillus thuringiensis Using Silver Nanoparticles Reduced with Hydroxylamine and with Citrate Capped Borohydride

Table 1

Tentative assignment of vibrational bands for (a) normal Raman spectrum of Bt and SERS spectra of Bt using (b) citrate capped borohydride reduced Ag-NPs and (c) hydroxylamine reduced Ag-NPs.

Vibration mode	a	b	c
	Raman shift/cm^−1
S–S stretching of cysteine in spore coat		527	526
C–C skeletal of carbohydrates		570	587
		1049	1065
C–S stretching of cysteine in spore coat		637
N–H deformation of amide II in CaDPA		657	657
glycosidic ring of NAG and NAM	753	732	728
C=C deformation of tyrosine		959	962
C–N and C–C stretching	1130
C–H in plane bending of CaDPA		1017
=C–C= of lipids or C–N aromatic in proteins	1144	1148	1134
amide III		1216	1246
		1276
C–NH2 stretching of amide II		1336	1326
COO^− stretching in CaDPA		1392	1377
C–H deformation of lipids		1463	1465
C=C ring stretching of lipids	1588	1595	1590
amide I		1658	1705