Rapid in situ biosynthesis of gold nanoparticles in living platelets for multimodal biomedical imaging

Inspired by the nature, the biomimetic nanomaterial design strategies have attracted great interest because the bioinspired nanoplatforms may enhance the functionality of current nanoparticles. Especially, the cell membrane-derived nanoparticles can more effectively navigate and interact with the complex biological microenvironment. In this study, we have explored a novel strategy to rapidly in situ biosynthesize gold nanoparticles (GNPs) in living platelets with the help of ultrasound energy. Firstly, under the ultrasound exposure, the biocompatible chloroauric acid salts (HAuCl₄) can be enhanced to permeate into the platelet cytoplasm. Then, by the assist of reducing agent (NaBH₄ and sodium citrate) and platelet enzyme, GNPs were fast in situ synthesized in intra-platelets. The biosynthesized GNPs had a size of about 5 nm and were uniformly distributed in the cytoplasm. Atomic absorption spectrometry (AAS) showed the synthesized amount of Au is (12.7 ± 2.4) × 10^-3 pg per one platelet. The GNPs in platelets can produce Raman enhancement effect and further be probed for both dark-field microscopy (DFM)-based imaging and computed tomography (CT) imaging. Moreover, the platelets were not activated and remained aggregation bioactivity when intra-platelet GNPs synthesis. Therefore, such mimicking GNPs-platelets with in situ GNPs components remain inherent platelet bioactivity will find potential theranostic implications with unique GNPs properties.