Alizarin Red fluorescence imaging for nano calcification

Abstract The formation of calcium phosphate (calcification) has been observed in a variety of healthy and diseased tissues and contributes to a wide range of pathologies. In physiological and pathological mechanisms, calcification begins at the nano scale and then develops into structures that range from a few micrometres to several centimetres. Fluorescence microscopy can be an efficient way to visualise such early calcification and its interaction with cells and proteins. The limited shelf life and high cost of commercial dyes for staining calcification, however, can be problematic when using this imaging method. Here, we aim to evaluate the effectiveness and stability of Alizarin Red (AR) as a fluorescent staining agent for nano and micro calcified structures. Our results show that AR staining for nano and micro calcified structures is a simple, reliable, effective, and quite inexpensive method to visualize calcification at the nano and micro scale in biological samples.