Enhanced bovine serum albumin absorption on the N-hydroxysuccinimide activated graphene oxide and its corresponding cell affinity

•The BSA absorption ability of the N-hydroxysuccinimide activated graphene oxide (GO) was equal to 1.8-fold of the pure GO.•The N-hydroxysuccinimide activated GO showed better BSA binding stability.•More vinculin and integrin α5 were visible in the mBMSCs cultivated on the BSA covalent bonded GO surface.

By successively reacting with N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), the carboxyl on the graphene oxide (GO) surface was successfully activated into NHS active ester. In this study, bovine serum albumin (BSA) was selected as a model protein, used for studying the protein absorption capacity of the NHS activated GO (GO-EDC-NHS). Approximately 12.75 mg of BSA could be covalent bonded onto the GO-EDC-NHS surface (BSA-CB-GO), whereas only 6.83 mg of BSA physical absorbed onto the GO surface (BSA-NB-GO). With a 168 h of phosphate buffer saline (PBS) soaking, the BSA accumulative desorption ratio, which was accordingly assigned to the BSA-NB-GO and the BSA-CB-GO, was separately 29.91 wt% and 2.95 wt%. Consequently, it proved GO-EDC-NHS exhibited more stable and stronger BSA absorption capacity. As compared to the mouse bone marrow mesenchymal stem cells (mBMSCs) cultivated on the BSA-NB-GO surface, the immunofluorescence staining images showed that more vinculins and integrin α5 were visible in the mBMSCs cultivated on the BSA-CB-GO surface, they also produced more distinct stress fibers and actin-containing microfilaments. In summary, BSA-CB-GO possesses an excellent cell affinity, which can be considered as a promising functional material used for promoting the bone remodeling.

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