. 2019 Feb 5;9(8):4435–4444. doi: 10.1039/c8ra10049g

Curve-fitted inverted second-derivative amide I spectrum of ultrasmall AuNPs binding BSA at different temperature. The inversion of second-derivative spectrum was done by factoring by −1^a.

Assignment	Frequency (cm⁻¹)	20 °C, percent (%)		37 °C, percent (%)		50 °C, percent (%)		70 °C, percent (%)
Assignment	Frequency (cm⁻¹)	Corona	BSA	Corona	BSA	Corona	BSA	Corona	BSA
α-Helix	1656 ± 2	77	62	68	59	65	56	46	36
β-Sheet	1643–1623	9	12	16	15	12	15	30	27
β-Sheet	1698–1689	9	12	16	15	12	15	30	27
β-Turn	1687–1666	11	8	8	6	10	10	7	6
Random	1648 ± 2	0	10	6	13	9	14	7	14
Side chain	1623–1600	3	3	2	2	2	4	16	17

Secondary structure contents were obtained from curve-fitting the inverted FT-IR second-derivative amide I spectra as shown in Fig. 2, 4 and 5.

Curve-fitted inverted second-derivative amide I spectrum of ultrasmall AuNPs binding BSA at different temperature. The inversion of second-derivative spectrum was done by factoring by −1a.