Red-emissive silicon nanodots with highly biocompatible for mitochondrial dynamic tracking and blood-brain barrier penetration imaging

Abstract

As one of the most indispensable organelles in eukaryotic cells, mitochondria are the primary site of cellular energy acquisition. Visual monitoring of mitochondria is an important way to understand mitochondrial morphology and cellular activities. However, it is difficult to achieve long-term localization and tracking due to the poor photostability of commercial mitochondria-targeted dyes. In this work, red-emissive silicon nanodots (R-SiNDs) with a highly mitochondrial-targeting and optimal emission peak at 614 nm were designed. The absolute quantum yield (QY) was up to 22.68%, while Pearson’s correlation coefficient in co-localization analysis was as high as 0.94. Subsequently, the long-term dynamic processes of mitochondrial fusion, division and interaction with lipid droplets were clear visualization in living cells based on good photostability and high photoluminescence efficiency. More interestingly, R-SiNDs without any other modification exhibited wonderful blood-brain barrier (BBB) penetration capacity and were accumulated in the central canal of the spinal cord of zebrafish. Therefore, the as-prepared R-SiNDs can not only be used to study mitochondrial dynamics, but also provide a reliable basis for diagnosing mitochondria-related brain diseases, which is of great value in biomedical applications.