One-step on-chip preparation of nanoparticle-conjugated red blood cell carriers

Red blood cell (RBC)-based carriers have emerged as promising vehicles for drug delivery due to their inherent biocompatibility and biodegradability. Traditional methods for loading nanoparticles (NPs) onto RBC surfaces often involve labor-intensive processes like incubation and multiple centrifugation steps, limiting their practicality and controllability. In this study, we introduce a fully integrated acoustofluidic platform that enables one-step preparation of NP-loaded RBC carriers with controlled modification and on-site purification. By incorporating a high-frequency bulk acoustic wave (BAW) resonator into a microfluidic chip, we utilize acoustic streaming effects to manipulate the movement and interaction of RBCs and NPs within the microchannel. This design allows for precise control over NP loading efficiency by adjusting the input power to the resonator. Experimental results using 200 nm positively charged fluorescent NPs demonstrate that our platform significantly enhances the interaction between RBCs and NPs, achieving efficient and controllable surface loading of NPs onto RBCs. Furthermore, the platform simplifies post-processing by directing excess NPs to waste outlets, eliminating the need for repetitive washing and centrifugation. This acoustofluidics approach not only automates the loading process but also offers high controllability, highlighting its potential for various applications in particle and cell surface modification.