One-step biomimetic coprecipitation method to form calcium phosphate and hemoglobin composite nanoparticles for biosensing application

A simple one-step biomimetic coprecipitation method is reported to prepare a protein based biosensor by immobilizing calcium phosphate/hemoglobin composite nanoparticles directly onto glassy carbon electrode surface. Atomic force microscopy (AFM), attenuated total reflection spectra (ATR) and electrochemical method were used to characterize the as-prepared composite nanoparticles. Hb in the composite film kept their biological activity well, realized its direct electrochemistry with the formal potential of −0.363 V in pH 7.0 phosphate buffer solution and gave excellent electrocatalytic performance to the reduction of hydrogen peroxide, by which the mediator-free biosensors could be fabricated. Compared to other immobilization methods, this system not only avoids the tedious synthesis of nanoparticles and the use of reagent detrimental to biomolecules but also possesses the advantages of simple preparation and low cost.