RESUMEN
Ca2+ is one of the most important second messengers in cells. A far-red to near-infrared (NIR) Ca2+ fluorescent probe is useful for multi-color imaging in GFP or YFP-expressing biosamples. Here we developed a cytosolically localized far-red to NIR rhodamine-based fluorescent probe for Ca2+, CaSiR-2 AM, while rhodamine dyes are basically localized to mitochondria or lysosomes in cells.
Asunto(s)
Calcio , Colorantes Fluorescentes , Iones , Lisosomas , RodaminasRESUMEN
Folate receptors (FRs) are membrane proteins involved in folic acid uptake, and the alpha isoform (FR-α) is overexpressed in ovarian and endometrial cancer cells. For fluorescence imaging of FRs inâ vivo, the near-infrared (NIR) region (650-900â nm), in which tissue penetration is high and autofluorescence is low, is optimal, but existing NIR fluorescent probes targeting FR-α show high non-specific tissue adsorption, and require prolonged washout to visualize tumors. We have designed and synthesized a new NIR fluorescent probe, FolateSiR-1, utilizing a Si-rhodamine fluorophore having a carboxy group at the benzene moiety, coupled to a folate ligand moiety through a negatively charged tripeptide linker. This probe exhibits very low background fluorescence and afforded a tumor-to-background ratio (TBR) of up to 83 in FR-expressing tumor-bearing mice within 30â min. Thus, FolateSiR-1 has the potential to contribute to the research in the field of biology and the clinical medicine.
Asunto(s)
Colorantes Fluorescentes/química , Receptores de Folato Anclados a GPI/metabolismo , Regulación Neoplásica de la Expresión Génica , Imagen Molecular/métodos , Relación Señal-Ruido , Animales , Línea Celular Tumoral , Colorantes Fluorescentes/síntesis química , Colorantes Fluorescentes/metabolismo , Ácido Fólico/metabolismo , Humanos , Ratones , Rodaminas/síntesis química , Rodaminas/química , Rodaminas/metabolismo , Factores de TiempoRESUMEN
Si-Rhodamines are bright fluorophores with red to near-infrared (NIR) emission, and are widely used for fluorescence imaging of biological phenomena. Here, in order to extend the scope of Si-rhodamine fluorophores, we established a versatile synthesis of unsymmetrical Si-rhodamines. To illustrate its value, we used one of these new fluorophores to synthesize a far-red to NIR fluorescence probe for hypoxia, and showed that it can visualize hepatic ischemia in mice in vivo.