Fast Lateral Imbibition on a Wood Ear-Like Substrate by Patterning Cellulose on OSTE Microneedle Array

Paper-based microfluidics and microarray structures are essential components of microfluidic technology. In this work, we developed a wood ear-like substrate using a bottom-up approach to pattern cellulose on the surface of an OSTE microneedle array, mimicking the wood ear structure and enabling rapid lateral liquid imbibition. The substrate consists of two layers: the bottom layer is an OSTE microneedle array, and the top layer is cellulose by deposition. Cellulose is dropped onto the microneedle array, where it self-assembles to form a wood earlike structure with rapid lateral wicking properties. Flow experiments showed that this composite substrate exhibited faster liquid flow compared to the control group, and the average flow rate increased by ~ 36%. Further analysis showed that the cellulose-OSTE microneedle array substrate had better performance on experimental stability. This study provides new insights into the development of paper-based microfluidic platforms and can support applications in point-of-care diagnostics in the near future.