Ratio of intensities of the Raman bands of IL-6 on Si substrates.

Bands intensities ratio	I 760/I760	I 1049/I1049	I 1403/I1403	I 1465/I1465	I 2943/I2943	Average ratio
1 μg ml−1/1 ng ml−1	3.25	2.91	2.63	3.05	2.26	2.82 ± 0.38
1 ng ml−1/1 pg ml−1	11.17	14.45	19.85	12.19	22.65	16.06 ± 4.98
1 μg ml−1/1 pg ml−1	36.25	41.98	52.15	37.19	51.00	43.71 ± 7.51