Figure legends
Figure 1. Strategies for detecting protein-protein interactions on the biochip. A directon-chip immunoprecipitation workflow detecting matched molecule monomers.
Figure 2. Immunological evaluation for biochip immobilization efficacy on two chemical modification surfaces modified by 16-amino-1-hexadecanethiol hydrochloride(16-AHDT) alone and surface modified by 16-AHDT in combination with sophorolipid (SL)via a direct on-chip immunoassay for serially diluted human IgG protein and Cy3-conjugated goat anti-human IgG antibody. 0.01M PBST-0.1%BSA buffer (pH 7.4) was used as a blank control.
Figure3. Surface chemical characterization of 16-AHDT-SL on gold biochips via attenuated total reflection Fourier-transform infrared spectroscopy (a) and atomic force microscopy: modified surface (b); unmodified surface (c).
Figure 4. Limit of detection of IL-2 and CD25 proteins on the biochip. (a) CD25-based IL-2 protein assay; (b) IL-2-based CD25 protein assay. Serially diluted target proteins were incubated on the receptor- or ligand-based biochips.
Figure 5. Immunological blocking assays for verifying the detection specificity ofserum ligand IL-2 and its receptor sCD25using the biochip.
Figure 6. Specific receptor- or ligand-based protein-protein interaction assays in seventy-seven hemophagocytic lymphohistiocytosis patients. (a): CD25-based IL-2 assay; (b): IL-2-based sCD25 assay.
Supplementary Table 1. Values and ratios of IL-2 and sCD25 assays in seventy-seven cases of HLH
Supplementary Table 2. Correlation analysis for serum sCD25 measurement in sixty-five cases of HLH using biochip and CLIA assays (Pearson test).
Supplementary Figure for Graphical Abstract.