Rapid measurement of hydrogen sulphide in human blood plasma using a microfluidic method

Abstract

Hydrogen sulfide (H 2 S) is emerging as an important gasotransmitter in both physiological and pathological states. Rapid measurement of H 2 S remains a challenge. We report a microfluidic method for rapid measurement of sulphide in blood plasma using Dansyl-Azide, a fluorescence (FL) based probe. We have measured known quantities of externally added (exogenous) H 2 S to both buffer and human blood plasma. Surprisingly, a decrease in FL intensity with increase in exogenous sulphide concentration in plasma was observed which is attributed to the interaction between the proteins and sulphide present in plasma underpinning our observation. The effects of mixing and incubation time, pH, and dilution of plasma on the FL intensity is studied which revealed that the FL assay required a mixing time of 2 min, incubation time of 5 min, a pH of 7.1 and performing the test within 10 min of sampling; these together constitute the optimal parameters at room temperature. A linear correlation (with R 2 ≥ 0.95) and an excellent match was obtained when a comparison was done between the proposed microfluidic and conventional spectrofluorometric methods for known concentrations of H 2 S (range 0–100 µM). We have measured the baseline level of endogenous H 2 S in healthy volunteers which was found to lie in the range of 70 μM – 125 μM. The proposed microfluidic device with DNS-Az probe enables rapid and accurate estimation of a key gasotransmitter H 2 S in plasma in conditions closely mimicking real time clinical setting. The availability of this device as at the point of care, will help in understanding the role of H 2 S in health and disease.

Reply to Radermacher et al. on “Serum Hydrogen Sulfide and Outcome Association in Pneumonia by the SARS-CoV-2 Coronavirus”

“…This elaborates the hypothesis that it is not the assay that leads to false-positive increased H 2 S levels, but that H 2 S increase may well be an intrinsic characteristic of Covid-19 described for the first time herein. H 2 S of healthy was also within reported ranges ( 7 ).…”

Can Blood-Circulating Factors Unveil and Delay Your Biological Aging?

“…As a result, the number of damaged mitochondria increases, which in turn stimulates the accumulation of ROS, contributing to further cell damage [ 29 , 33 , 37 ]. Together, increased metabolic activity, impaired mitochondrial function, insufficient concentration of protective redox molecules (e.g., H 2 S), and inflammation prompt high spending of NAD+ and ROS accumulation [ 85 , 86 , 261 ]. These events of cellular aging further trigger advanced pathological processes, accumulation of senescent cells, and development of age-related disorders [ 262 ].…”

“…An age-dependent decrease of the H 2 S concentration in plasma can be an objective indicator of age-related changes [ 82 , 84 , 85 ]. H 2 S and described above Cys-SSH can be easily measured by fluorescence and Dimedone switch tag methods [ 82 , 86 ].…”

Emerging analytical tools for the detection of the third gasotransmitter H2S, a comprehensive review

“…Another recent study developed a microfluidic method for the measurement of sulfide in blood plasma that relied on using the same fluorescent sensor dansyl azide, which confirmed the plasma matrix interference. Though a dilution step 3.3-fold dilution is required to reduce plasma interaction with exogenous sulfide [58] .…”