Peptide NGR Modified TiO2 Nanofiber Substrate for Circulating Tumor Cells Capture

The analysis of circulating tumor cells (CTCs) allows a noninvasive method of "real-time liquid biopsy" from the blood samples of cancer patients for the diagnosis of early-stage cancer, prognosis, and monitoring therapeutic response. In this study, we develop a simple, inexpensive, and reliable method that utilizes a small molecule peptide, the asparagine-glycine-arginine (NGR), as a capture probe for the selective enrichment and isolation of circulating tumor cells (CTCs). The multiscale TiO2 nanofibers are obtained by electrospinning and calcination. Bovine serum albumin (BSA) is decorated onto TiO2 nanofiber surfaces to inhibit non-target cell adhesion, while NGR peptides are conjugated onto the TiO2-BSA surface through the glutaraldehyde (GA) to specifically capture the target cells. The TiO2-BSA-NGR substrate exhibits a high capture sensitivity and efficiency from the mimical blood samples with PC-3 cancer cells as low as 10 cells/mL. The TiO2 nanofiber substrate can be a promising strategy for the capture and enumeration of CTCs in cancer progression monitoring.