An insight into the potentials of carbon dots for in vitro live-cell imaging: recent progress, challenges, and prospects.

Carbon dots (CDs) are a strong alternative to conventional fluorescent probes for cell imaging due to their brightness, photostability, tunable fluorescence emission, low toxicity, inexpensive preparation, and chemical diversity. Improving the targeting efficiency by modulation of the surface functional groups and understanding the mechanisms of targeted imaging are the most challenging issues in cell imaging by CDs. Firstly, we briefly discuss important features of fluorescent CDs for live-cell imaging application in this review. Then, the newest modulated CDs for targeted live-cell imaging of whole-cell, cell organelles, pH, ions, small molecules, and proteins are elaborately discussed, and their challenges in these fields are explained.

Renin inhibition by soyasaponin I: a potent native anti-hypertensive compound.

One way to control hypertension is inactivation of the Renin- Angiotensin- Aldosterone System (RAAS). Inhibition of renin as a rate-limiting step of this system is an effective way to stop up RAAS. It has been proved that soyasaponin I, an herbal compound obtained from soybeans, has anti-hypertensive effect via renin inhibition, so it has the potential of being an anti-hypertensive drug. Herein, some theoretical approaches such as Docking Simulation, Molecular Dynamics (MD) Simulation and MMPBSA analysis have been used to study how soyasaponin I inhibits renin at the structural level. The results of docking simulation and hydrogen bond pattern show that this ligand is able to bind to the active site of renin and a region near the active site. Results of MD simulation for renin - soyasaponin I complexes confirm that soyasaponin I binds to the active site of renin and has inhibition effect on it via competing with the substrate. Besides, according to MMPBSA analysis, the binding free energy for renin - soyasaponin I complex is -42.61 kcal/mol when it binds to the active site. Comparing to the peptide obtained from angiotensinogen, ΔG = -74.96 kcal/mol, it may inferred that although binding of soyasaponin I to the active site of renin does not have a complete competition with the substrate, it might attenuate the formation of renin - angiotensinogen complex and have partial non-competitive effect. The results of this survey might be helpful to design partial non - competitive renin inhibitors with pharmaceutical capability.