Fluorescent ruby nanocrystals for biocompatible applications

Abstract

Chromium-doped aluminum oxide (ruby) micro- and nanocrystals have shown a sharp and strong fluorescence emission that linearly depends on pressure and temperature. They also have an exceptional photostability and a high quantum efficiency. In spite of their widespread use as pressure sensors, only a few earlier studies have used ruby nanocrystals as efficient fluorescent bioimaging probes. However, their use at biocompatible excitation/detection wavelengths and toxicity assessment against human living cells remain unexplored. In this work, we show that ruby nanocrystals can be efficiently excited and detected within the biological transparency window. We also examined the biocompatibility of ruby nanocrystals in human living cells, which exhibited no detectable cytotoxicity. This makes ruby nanocrystals among the best alternative fluorescent probes for promising biological applications.

Red-Emitting Cr3+ on α-Al2O3:Cr Spheres Obtained in Seconds Using Laser Processing

“…Recently, the remarkable optical properties of α-Al 2 O 3 :Cr have been exploited in a myriad of applications such as temperature, pressure, and stress sensors [11][12][13][14], dosimeters in ionizing radiation therapy [15][16][17], red-emitting phosphors for plant growth [18,19], or fluorescent probes for biological applications [20], among others. In addition, doped polycrystalline alumina is a material of excellence in high-power phosphor color converters or laser gain media [21,22].…”