Fig. 2: Physicochemical characterization of BEETLES² membrane.

a AAO membrane with an aligned 20 nm pore as a substrate, showing no permselectivity. b Functionalization of RBCM onto the AAO membrane, showing permselectivity and tunability under applied pressure. c Fabrication and topological analysis of BEETLES² membrane. d AFM images showing topography and cross-sectional profiles from the height map images of bare AAO and BEETLES² membrane. (e, f) KPFM analysis of (e) surface potential images of bare AAO and BEETLES² membrane and f Frequencies of surface potential depending on RBCM concentration (0-4% (v/v)). Data are from three pooled experiments (0% RBCM, n = 30; 0.1-4% RBCM, n = 50). g FRAP study of fluorescence intensity with time and images showing RBCM on the substrate is well preserved its lateral diffusivity and fluidity in 2D planar deposition and the recovery of ~80% of the original value was done in 150 s (spot radius: 20 μm). Error bars represent standard deviation from the mean. Cartoons in panels a–c were created with BioRender.com. BEETLES², bioengineered enrichment tools for the LFA with enhanced sensitivity and specificity; AAO nanoporous anodic aluminum oxide, LFA lateral flow assay, RBCM red blood cell membrane, AFM atomic force microscopy, FRAP fluorescence recovery after photobleaching, KPFM Kelvin probe force microscopy.