Article in Nanoscale

Researchers Aljaž Kavčič, MSc., Rok Podlipec, PhD, Ana Krišelj, MSc., Andreja Jelen, PhD and Assist. Prof. Matjaž Humar, PhD in collaboration with a colleague from the Faculty of Mechanical Engineering, University of Ljubljana have published a paper titled Intracellular biocompatible hexagonal boron nitride quantum emitters as single-photon sources and barcodes in the journal Nanoscale.

In this work, they demonstrate single-photon emission from hexagonal boron nitride (hBN) color centers embedded inside live cells and their application to cellular barcoding. The emission from live cells was observed as multiple diffraction-limited spots, which exhibited excellent single-photon characteristics with high single-photon purity of 0.1 and superb emission stability without photobleaching or spectral shifts over several hours. Due to different emission wavelengths and peak widths of the color centers, they were employed as barcodes. Each barcode can exist in one out of 470 possible distinguishable states and a combination of a few barcodes per cell can be used to uniquely tag virtually an unlimited number of cells. The barcodes developed here offer some excellent properties, including ease of production by a single-step procedure, biocompatibility and biodegradability, emission stability, no photobleaching, small size and a huge number of unique barcodes, while, due to the single photon emission, presented concepts could in future be extended to quantum-limited sensing and super-resolution imaging.