Py-FITC: a new fluorescent probe for live cell imaging of collagen-rich tissues and ionocytes

Polypyrrole-based polyamides are used as sequence-specific DNA probes. However, their cellular uptake and distribution are affected by several factors and have not been extensively studied . Here, we generated a series of fluorescence-conjugated polypyrrole compounds and examined their cellular distribution using live zebrafish and cultured human cells. Among the evaluated compounds, Py-FITC was able to visualize collagen-rich tissues, such as the jaw cartilage, opercle and bulbus arteriosus, in early-stage living zebrafish embryos. Then, we stained cultured human cells with Py-FITC and found that the staining became more intense as the amount of collagen was increased. In addition, Py-FITC-stained HR cells, which represent a type of ionocyte on the body surface of living zebrafish embryos. Py-FITC has low toxicity, and collagen-rich tissues and ionocytes can be visualized when soaked in Py-FITC solution. Therefore, Py-FITC may be a useful live imaging tool for detecting changes in collagen-rich tissue and ionocytes, including their mammalian analogues, during both normal development and disease progression.