A Polymeric Nanobeacon for Monitoring the Fluctuation of Hydrogen Polysulfides during Fertilization and Embryonic Development.

Fertilization and early embryonic development as the beginning of a new life are key biological events. Hydrogen polysulfide (H2 Sn ) plays important roles during physiological regulation, such as antioxidation-protection. However, no report has studied in situ H2 Sn fluctuation during early embryonic development because of the low abundance of H2 Sn and inadequate sensitivity of probes. We herein construct a polymeric nanobeacon from a H2 Sn -responsive polymer and fluorophores, which is capable of detecting H2 Sn selectively and of signal amplification. Taking the zebrafish as a model, the polymeric nanobeacon revealed that the H2 Sn level was significantly elevated after fertilization due to the activation of cell multiplication, suppressed partially during embryonic development, and finally kept steady up to zebrafish emergence. This strategy is generally accessible for biomarkers by altering the responsive unit and significant for facilitating biological analysis during life development.

Self-Immolative Dye-Doped Polymeric Probe for Precisely Imaging Hydroxyl Radicals by Avoiding Leakage.

For sensing low abundance of biomarkers, utilizing nanocarriers to load dyes is an efficient method to amplify the detected signal. However, the non-specific leak of the internal dyes in this approach is accompanied by false positive signals, resulting in inaccurate signal acquirement. To address this issue, in this work, we reported a novel signal amplification strategy with dye as a scaffold to construct a self-immolative dye-doped polymeric probe (SDPP). In our proposed approach, the dyes were covalently integrated into the main chain of a polymer, which can avoid the non-specific leak of the dye when used in a rigorous biological environment, thus evading the false positive signal. As a prototype of this concept, a SDPP, which responds to hydroxyl radicals (•OH), was rationally fabricated. Upon being activated by •OH, SDPP will liberate the dye through a self-immolative reaction to bind with protein for amplifying the fluorescence signal. Compared with a dye-loaded nanoprobe, SDPP can precisely track intracellular basal •OH levels and visualize the •OH associated with myocarditis in vivo. More importantly, the attempt in this work not only provides an effective molecular tool to investigate the role of •OH in cardiopathy, but also puts forward a new direction to current signal-amplifying strategies for precisely and reliably acquiring the intracellular molecular information.