Fig. 2: Grafting OPA groups onto microparticles accelerates clot formation and strengthens clots through covalent crosslinking.

a–c Rheological analysis of blood clots with or without microparticles. Schematic illustration (a) and representative time sweeps (b) of the storage modulus (G’) and loss modulus (G”) for whole blood (200 μL), and whole blood (200 μL) with xHA (without OPA groups) or oHA (with OPA groups) microparticles (15 mg). The gelation time was defined as the time point at which G’ surpass G”. c Gelation time and G’ (measured via rheological tests) for blood clots with or without microparticles (n = 3 independent samples). The G’ was recorded at 300 s. d Digital photographs showing an oHA@Blood clot withstanding a weight of 250 g. The composite (oHA@Blood clot) was fabricated by adding 30 mg of oHA microparticles to 400 μL of whole blood within a mold (1.5 mm-diameter) and incubating at 37 °C for 300 s. e–g Identification of the oHA-clot interface. e Representative confocal laser scanning microscope (CLSM) images of a natural plasma clot, an xHA@Plasma clot, and an oHA@Plasma clot. Purple fluorescence corresponds to the rhodamine-labeled plasma proteins. f Average fluorescence intensity of regions of interest (ROI, R_1, and R₂) in (e, n = 5 independent samples). g Average Young’s modulus of three characteristic regions in an oHA@Plasma clot, assessed by AFM tapping mode (n = 5 independent samples). h Time-dependent plots for G’ and G” versus strain rate for a natural blood clot, an xHA@Blood clot, and an oHA@Blood clot. i Fibrinolysis and anti-fibrinolysis behaviors of natural blood clots, xHA@Plasma clots, and oHA@Plasma clots, quantified by measuring the absorbance of supernatant at 405 nm (n = 5 independent samples). j Schematic illustration and dynamic clotting tests of blood with or without xHA microparticles, oHA microparticles, or commercially available hemostats (n = 3 independent samples). Data are presented as means ± s.d., and all statistical analyses were performed using an unpaired two-tailed Student t test. * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001. Source data are provided as a Source Data file.