Opportunities for hybrid diamond nanosensors targeting photothermal applications in biological systems

Functionalized diamond nanocrystals persistently expand their use for sensing and labeling in a biological context. The surface of such crystals modified chemically adds additional modality to such applications. In this Perspective, we discuss mainly applications in nanothermometry but begin with a brief general introduction of fluorescent nanodiamonds. Then we consider temperature at the sub-cellular environment, explain the working principle of fluorescent nanodiamonds as temperature probes, and demonstrate their biological applications from the literature. The application of nanohybrids (such as heater-thermometer hybrids built within a single nanoparticle) in biological cells will be covered with more details. We summarize recent results of intracellular measurements to estimate that 0.1 nJ of heat released in a cellular hot spot of 1-mu m radius can produce a 1-K temperature rise lasting for about 50 mu s and repeatable approximately every 2 ms. Our view on the reason for limitations in biological applications of nanodiamonds concludes the review.(c) 2021 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

Functionalized diamond nanocrystals are widely used for sensing and labeling in biological contexts, particularly in the field of nanothermometry. Fluorescent nanodiamonds as temperature probes show great potential for biological applications, but there are limitations that need to be addressed.