Nanoparticles (NP) are rapidly becoming more common in the medical field. Applications like imaging, drug delivery, and therapeutics require careful design of the surface chemistry of the particle to reach their target. When NPs are introduced into a biological system the particles encounter a milieu of proteins that alter the surface chemistry by forming a “protein corona”. Increasing evidence suggests that the biological fate and targeting efficiency of NPs are heavily influenced by the protein corona necessitating fundamental research into adsorption of proteins onto NP surfaces. The aim of this work is to employ the facile and complimentary methods of plasmon shift and hydrodynamic diameter shift to probe the adsorption of proteins to negatively and positively charged gold nanoparticle (AuNP) surfaces. Bovine serum albumin (BSA), β-lactoglobulin (BLG), and α-amylase (A-Amy) were chosen for this study because these proteins denature via different pathways under acidic conditions suggesting that they might adsorb differently to highly charged NP surfaces. Citrate AuNPs were used as negatively charged surface while poly(allylamine hydrochloride) (PAH) was used as the positive surface. Binding constants were measured for all three proteins on the citrate surface, and both measurement methods were in good agreement. A binding constant was measured for A-Amy on PAH AuNPs, but could not be determined for BSA and BLG. Rather large protein/particle agglomerates formed that increase in size with increasing protein concentration. These results confirm that the underlying surface chemistry plays an important role in adsorption, and that the identity of the protein influences adsorption behaviors.

Protein adsorption to charged nanospheres

251st National Meeting (2016)

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