Peptide-Functionalized Nanomaterials for the Efficient Isolation of HER2-Positive Circulating Tumor Cells.

The detection of circulating tumor cells (CTCs) with a specific antigen expression is necessary in therapeutic response monitoring and targeted therapy guidance. The existence of human epidermal growth factor receptor 2 (HER2) and the concentration of HER2-positive CTCs are strong indicators for patient diagnosis, prognosis, and therapeutic monitoring. Herein we report the direct isolation of HER2-positive CTCs by peptide-functionalized nanomaterials. We designed and screened out a peptide as an HER2 antibody alternative demonstrating high HER2 affinity and selectivity. This HER2 recognition peptide bound efficiently with HER2 at the ligand-binding domain. Efficient HER2-positive CTC capture and detection were demonstrated using magnetic nanoparticles functionalized with the HER2 recognition peptide.