CNTs recruit different serum protein assortments on the biocorona

Carbon nanotubes (CNT) have a highly reactive surface that has the intrinsic ability of recruiting surrounding proteins on their surfaces through non-covalent interactions. The CNT biocorona has a chief role in CNT toxicity... [ view full abstract ]

Carbon nanotubes (CNT) have a highly reactive surface that has the intrinsic ability of recruiting surrounding proteins on their surfaces through non-covalent interactions. The CNT biocorona has a chief role in CNT toxicity and bioaccumulation. This protein coating has many effects in vivo providing the nanotube with different biomimetic identities,1,2 dictating the bio-distribution,3 being critical in cellular recognition and CNT biodegradation.4
The formation of the protein corona has been extensively studied in recent years but the underlying biochemical processes taking place on the proteins that bind the nanotube are not completely understood. The interaction of proteins with the CNTs depends on the actual physicochemical properties of the surface of the nanotube,5,6 and also on the structure of the interacting proteins. Most soluble proteins (such as serum albumin) have hydrophobic cores that are only exposed after pseudo-denaturation.7 The exposure of the polypeptide core by partial unfolding of the protein depends on many factors, among others, (i) temperature, (ii) environmental reducing conditions, (iii) time, (iv) solvents, (v) detergents, etc.8 Accordingly, one single protein can display different interactive behaviors with the same nanomaterial depending on these conditions. Here we show how the protein corona of CNTs functionalized with blood serum, recruits diverse assortments of serum proteins on the nanotube surface when exposed to different conditions during functionalization. Our results reveal that the functionalization of the CNT is qualitative and quantitative dependent on all the above environmental conditions.

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