On-chip integrated labelling, transport and detection of tumour cells

Microflow cytometry represents a promising tool for the investigation of diagnostic and prognostic cellular cancer markers, particularly if integrated within a device that allows primary cells to be freshly isolated from the solid tumour biopsies that more accurately reflect patient-specific in vivo tissue microenvironments at the time of staining. However, current tissue processing techniques involve several sequential stages with concomitant cell losses, and as such are inappropriate for use with small biopsies. Accordingly, we present a simple method for combined antibody-labelling and dissociation of heterogeneous cells from a tumour mass, which reduces the number of processing steps. Perfusion of ex vivo tissue at 4°C with antibodies and enzymes slows cellular activity while allowing sufficient time for the diffusion of minimally active enzymes. In situ antibody-labelled cells are then dissociated at 37°C from the tumour mass, whereupon hydrogel-filled channels allow the release of relatively low cell numbers (<1000) into a biomimetic microenvironment. This novel approach to sample processing is then further integrated with hydrogel-based electrokinetic transport of the freshly liberated fluorescent cells for downstream detection. It is anticipated that this integrated microfluidic methodology will have wide-ranging biomedical and clinical applications.