The gelatin coating-formed nanostructures on the surface of silica microbeads enhanced cell capture. TEM images of (A) anti-EpCAM and anti-CD146-coated SiO2 MB and (B) CTC-beads (anti-EpCAM&anti-CD146 SiO2@Gel MBs). SEM images of target cells captured on (C) anti-EpCAM and anti-CD146-coated SiO2 MB and (D) on CTC-beads. (A, B, scale bar, 50 nm; C, D, scale bar, 3 μm). (E) Cell-capture efficiency for two cell lines (MCF-7 and HCT116, 105 cells mL-1 in DMEM) using bare silica microbeads (SiO2 MBs) and gelatin nanoparticle-coated silica microbeads (SiO2@Gel MBs). All beads were functionalized with anti-EpCAM and anti-CD146. Error bars represent the standard deviations (n≥3).