Abstract
Affinity reagents that binding to specific targets are essential tools for clinical diagnostics and targeted therapeutics. However, benchtop methods for probing for target molecules with affinity reagents have some several drawbacks; they are, time-consuming, labor-intensive, and require of large, typically expensive instruments that require both expensive reagents and large sample quantities. Microfluidic platforms could potentially automate the screening process within a shorter period of time. Phage display peptide library libraries are promising tools for in selection of cell surface peptides and could be used for this purpose. In recent years, a subpopulation of tumor cells are considered as cancer stem cells, or as tumor initiation cells which are of great interest. The subpopulation of cells is believed to have an ability to initiate the differentiation of cells to cancer cells, and they are the main cause of metastesis. A specific peptide that can recognize and differentiate cancer cells and cancer stem cells is extremely useful in early diagnosis and target therapeutics. In this study, selection of M13 phage displayed peptides that bind to colon cancer cells and colon cancer stem cells using an integrated microfluidic system was successfully demonstrated. In addition to positive selection process, we provided a negative selection into the screening process of phage display library. Compared with the traditional method (which needs at least one month), the total selection process was significantly shortened to 36 hours. In this study, 3 candidates for colon cancer cell and 4 candidates for colon cancer stem cells after the total selection process were successfully screened. The selected peptides were tested to show relatively high specificity on target cells. The developed technique may be promsing for early diagnosis of cancer and target therapeutics for metastasis cancer patients.