The refractive index points to the interplay between light and objects, which is rarely studied down to micronano scale. Herein, we demonstrated a conventional bright-field imaging technique to determine the local refractive index of single particles combined with a series of refractive index standard solutions. This intrinsic optical property is independent with the particle size and surface roughness with a single chemical component. Furthermore, we accurately tuned refractive index of homemade core−shell nanoparticles by adjusting the ratio of core-to-shell geometry. This simple and effective strategy reveals extensive applications in exploring, designing and optimizing the physical and optical characterizations of composite photonic crystals with high precision. It also indicates potentials in the field of reflective displays, optical identification, and encryption.
Na+/H+ antiporters are major secondary transporters that regulate pH and sodium homeostasis by enabling transmembrane exchanges of Na+ with H+ in opposite directions, both are essential cations. Although their crystal structures have been well characterized1-3, the transport dynamics of Na+/H+ antiporters during action in living cells remained largely unexplored. Herein, intermittent blinking of the spontaneous bioluminescence from single native bioluminescent bacteria, P. phosphoreum, was reported, investigated and attributed to the stochastic gating of Na+/H+ antiporters between the active and inactive conformations. Each gating event caused the rapid depolarization and recovery of membrane potential within several seconds, accompanying with the intermittent bioluminescence blinking due to the transient inhibitions on the activity of respiratory chain. Temperature-dependent measurements further revealed that the conformational change was thermodynamically driven with an activation energy barrier of 20.3 kJ/mol. While the stochastic gating of ion channels has been well understood for decades4,5, this study uncovered the stochastic gating dynamics of Na+/H+ antiporters, another major pathway for ion transmembrane transports, in single native bacteria without any genetic engineering or chemical labeling. It also opened the door for P. phosphoreum to serve as new model bacteria for reporting the physiological and metabolic status with spontaneous bioluminescence emission.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.