Effect of iron oxide nanoparticles on fibrin gel formation and its fractal dimension

In this paper, we studied the influence of nonmagnetic iron oxide nanoparticles on fibrin gel formation and its structure using dynamic light scattering. The surface of nanoparticles produced by a new method in acoustoplasma discharge with cavitation has specific morphology and accelerates the rate of fibrin gel formation, i.e., activates the enzyme thrombin. We studied changes in the form of autocorrelation functions of the scattered light intensity for fibrinogen-thrombin samples with different thrombin concentrations as well as the nanoparticles addition. Appearance of the power-law term in the function was an indicator of gel formation in the sample. Application of Martin's theory allows estimating the exponent φ of power-law function and the contribution of the diffusive mode of protofibrils. We found that an increase in thrombin concentration or its activation with iron oxide nanoparticles leads to decreasing contribution of the diffusive mode, and increasing contribution of the exponent of power-law function. The values of fractal dimension D_f calculated using Muthukumar's theory are 1.61 ± 0.13 and 1.69 ± 1.11 for samples with low and high concentrations of thrombin respectively and 1.77 ± 0.08 for the sample with thrombin activated by nanoparticles. Such an increase in fractal dimension shows an increase in the complexity of the fibrin gel structure (or density).