Label-free measurements of the reaction kinetics of a small sample volume are essential for efficient drug discovery, requiring methods and systems that are rapid, accurate, and cost-effective. Herein, we present an integrated optofluidic system for label-free characterization of reactions in a nanoliter reagent volume. This system contains a droplet-based microfluidic sampling section and an optical fiber-based spectroscopy detection section. By manipulating droplets containing reagents at certain concentrations at different times, quantifiable measurements via absorption spectroscopy can be made in a simple, sensitive, and high-throughput manner. We have demonstrated our system's capability by performing potency (IC50) assays of an inhibitor in a TEM-1 β-lactamase (enzyme) and nitrocefin (substrate) system. This integrated platform can potentially provide an automated, label-free, and low-cost method for many other assays of reaction kinetics.
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http://dx.doi.org/10.1177/2211068214549625 | DOI Listing |
Anal Chim Acta
January 2025
College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China. Electronic address:
Background: The rapid and sensitive detection of nitrite is important to human health protection due to its carcinogenic and teratogenic risks with excessive intake. The Griess assay is widely applied for the design of nitrite detection system. However, its relatively slow reaction kinetics and sole colorimetry mode might limit it's the sensitivity and practical application.
View Article and Find Full Text PDFBMC Chem
January 2025
Nuclear Chemistry Department, Hot Laboratories Center, Egyptian Atomic Energy Authority, P.O. 13759, Cairo, Egypt.
In this work, selenium (IV) ions were adsorbed from aqueous solutions by the strongly basic anion exchange resin Amberlite IRA-400. The morphology of the resin before and after Se(IV) sorption was investigated using different techniques such as energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). To determine the ideal sorption conditions, a batch approach was used to examine the variables affecting Se(IV) sorption performance, including pH, shaking time, adsorbent dosage, initial metal ion concentration, and temperature.
View Article and Find Full Text PDFGait Posture
December 2024
Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
Background: Carbon fiber custom dynamic orthoses have been used to improve gait mechanics after lower limb trauma in military service members, with the goal of restoring function and improving outcomes. However, the effects of commercially available carbon fiber orthoses available to civilians on lower extremity joint kinetics and kinematics are poorly understood.
Research Question: The aim of this study was to examine the effect of two commercially available orthoses on lower extremity kinematics and kinetics in individuals with lower limb trauma.
Gait Posture
December 2024
School of Health and Exercise Sciences, The University of British Columbia Okanagan, Kelowna, British Columbia, Canada. Electronic address:
Background: To maintain standing balance, vestibular cues are processed and integrated with other sensorimotor signals to produce appropriate motor adjustments. Whole-body vestibular-driven postural responses are context-dependent and transformed based upon head and foot posture. Previous reports indicate the importance of intrinsic foot muscles during standing, but it is unclear how vestibular-driven responses of these muscles are modulated by alterations in stability and head posture.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Shiyan Key Laboratory of Quantum Information and Precision Optics, and School of Mathematics, Physics and Optoelectronic Engineering, Hubei University of Automotive Technology, Shiyan 442002, People's Republic of China.
The molecular energy transfer is crucial for many different physicochemical processes. The efficiency of traditional resonance energy transfer relies on dipole-dipole distance between molecules and becomes negligible when the distance is larger than ∼10 nm, which is difficult to overcome. Cavity polariton, formed when placing molecules inside the cavity, is a promising way to surmount the distance limit.
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