Adsorption of human blood plasma on nanodiamond and its influence on activated partial thromboplastin time

Ever increasing use of engineered nanodiamond (ND) into the human blood for various biomedical studies and applications has increased the demand to thoroughly understand the interaction of NDs with blood and its effect on blood coagulation. Here, we report on the study of adsorption of human blood plasma on various sized carboxylated nanodiamonds (cNDs) using UV/visible spectroscopy and Fourier transform infrared spectroscopy (FIR). The adsorption of human blood plasma on 5 nm and 100 nm sized cNDs is confirmed from UV/visible spectra. FTIR shows minor change in the shape of amide 1 absorption peak (1600-1700 cm(-1)) indicating that the protein secondary structure remains unaffected for human blood plasma. The influence of cNDs on the blood coagulation has been estimated using Activated Partial Thromboplastin Time (APTT) test. The APTT test is one of the standard tests used to investigate the efficacy of the intrinsic pathways of coagulation. The APTT test results indicate that 5 and 100 nm cNDs with various concentrations (10-500 mu g/ml) do not show delay in time when coagulation was initiated through the intrinsic pathway. (C) 2013 The Authors. Published by Elsevier B.V. All rights reserved.