ABSTRACT
Single-molecule studies offer deep insights into the essence of chemistry, biology, and materials science. Despite significant advances in single-molecule experiments, the precise regulation of the flow of single small molecules remains a formidable challenge. Herein, we present a flexible glass-based hybrid nanofluidic device that can precisely block, open, and direct the flow of single small molecules in nanochannels. Additionally, this approach allows for real-time tracking of regulated single small molecules in nanofluidic conditions. Therefore, the dynamic behaviors of single small molecules confined in different nanofluidic conditions with varied spatial restrictions are clarified. Our device and approach provide a nanofluidic platform and mechanism that enable single-molecule studies and applications in actively regulated fluidic conditions, thus opening avenues for understanding the original behavior of individual molecules in their natural forms and the development of single-molecule regulated chemical and biological processes in the future.
ABSTRACT
Gas-liquid interfaces (GLIs) are ubiquitous and have found widespread applications in a large variety of fields. Despite the recent trend of downscaling GLIs, their nanoscale fabrication remains challenging because of the lack of suitable tools. In this study, a nanofluidic device, which has undergone precise local surface modification, is used in combination with tailored physicochemical effects in nanospace and optimized nanofluidic operations, to produce uniform, arrayable, stable, and transportable nanoscale GLIs that can concentrate molecules of interest at the nanoscale. This approach provides a delicate nanofluidic mechanism for downscaling gas-liquid interfaces to the nanometer scale, thus opening up a new avenue for gas-liquid interface studies and applications.
Subject(s)
NanotechnologyABSTRACT
A photometric method to determine molecular oxygen in water was developed. When manganese(II) is oxidized by oxygen under alkaline conditions, the presence of polyphosphate can prevent precipitation due to a coacervate reaction. The oxidized manganese later dissolves in acid to form a pink Mn(III) species, which has a stable UV/vis spectrum. Monitoring of the oxygen concentration based on the absorbance of the pink Mn(III) species at 517 nm showed a strong correlation with both the Winkler method and an optical sensor. As a result, the present method can measure not only dissolved oxygen, but also fine bubbles oxygen in in the water sample with high reliability (0 - 26 mg dm-3, r2 = 0.9995). During this process, no significant interference from nitrite or metal ions was observed. The accuracy of the measurement was steady at high temperatures of the water samples (≤ 363 K).
