The binding isotherm for human IgG to MEL-A attached onto poly(2-hydroxyethyl methacrylate) beads.Different amounts of human IgG (0.1 to 12.0 mg) was added to the mixture ofMEL-polyHEMA composite (0.35±0.05 g) bearing 4.04 mg MEL-A per g ofpolyHEMA and 50 mM phosphate buffer (1M of Na2SO4, pH 6.4) (3 ml) in apolypropylene tube. The tube was incubated for 1 hr and then centrifuged. Theamount of bound protein was calculated by subtracting the unbound protein fromthe total added; the unbound protein was estimated by measuring the UVabsorbance of the supernatant. The binding constant and capacity were determinedfrom the equation for the Langmuir adsorption isotherm, q = (Q
C) / (1+K
C). MEL-A, mannosylerythritol lipid-A; polyHEMA, poly (2-hydroxyethyl methacylate).