Red-light-responsive coordination polymers nanorods: New strategy for ultrasensitive photothermal detection of targeted cancer cells.

Abstract

The development of highly sensitive and simple detection methods for cancer cells is an important challenge to achieve early cancer diagnosis and effective treatment. In this paper, folic acid (FA)-conjugated platinum (IV) methylene blue (MB) coordination polymers nanorods (denoted as FA-PtCPs NRs) were developed by the photochemical method. The structure of the PtCPs NRs was investigated using the meta-dynamics and genetic algorithms (MTD-GC) method, and it was found that the coordination bond was formed between platinum (IV) and N atoms of MB. The field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) indicated that the morphology of PtCPs NRs was rod-like. The resulting FA-PtCPs NRs was used for the specific and ultra-sensitive temperature detection of cancer cells based on PtCPs NRs as a signal trigger unit and FA as a target recognition tool. After three-step reaction, oxidized 3,3 ,5,5 -tetramethylbenzidine (ox-TMB) with photothermal effect was obtained. Under 660\xa0nm laser irradiation, such detection platform can convert the molecular recognition signal between FA and folate receptor (FR) of cancer cells into readable temperature value, which can be directly read by an ordinary thermometer, with a detection limit as low as 2\xa0cells/mL. In addition, FA-PtCPs NRs could be used as fluorescent probes for in-situ bioimaging. Therefore, this photothermal sensing platform has a broad prospect in the field of point-of-care detection of cancer cells.