Table 1. Position and possible corresponding metabolite of the Raman peaks detected in the conditioned culture medium.

Raman peaks detected in the cell culture medium and modulated in the intensity during conditioning time are listed. For each of them, the position in the spectrum and the possible corresponding metabolite, in accordance with the literature, are reported.

Peak (cm-1)	Possible attribution	References
584	Acetoacetate	[52]
658	Histidine	[48]
685	Proteins	[53]
727	Methionine	[47–48]
757	Cytocrome, Ring breath Tryptophan	[54–55]
768	Fumarate	[52]
828	Tyrosine	[47–48,50–52]
894	Glycine	[47–48,52]
1004	Phenylalanine	[47–48,50–52]
1121	Proteins: stretching CN	[56–57]
1128	Proteins: stretching CN; Carbohydrates: stretching C-O	[55]
1158	Acetoacetate	[52]
1180	Tyrosine	[47–48,50–52]
1203	Phenylalanine	[57]
1210	Nucleic acids: Thymine	[57]
1244	Amide III (β-Sheet)	[49–50]
1291	Fumarate	[52]
1316	Nucleic acids: Guanine; Proteins: C-H; Lipids	[55,58]
1336	Proteins: twisting (CH2, CH3)	[57]
1402	Deformation CH3 asym; Stretching COO-	[57]
1422	Nucleic acids: Adenine, Guanine	[56,59]
1488	Histidine	[50]
1521	Nucleic acids: Cytosine	[56]
1556	Tryptophan	[50]
1569	Proteins: Amide II	[56]
1596	Phenylalanine	[56]
1620	Amide I; C = C Tyrosine, Tryptophan, Lipids, stretching (C = C) olefinic	[55–56,60]