Real-time monitoring of the sucrose hydrolysis process based on two-photon coincidence measurements.

Zheng Peng,Zhiyuan Zhou,Tang Qing,Tongju Li,Chenhao Li,Meili Jiang,Xiaochun Zhang,Liu Yang

doi:10.1364/boe.432301

Abstract

Real-time measurement of the biochemical reaction process has important application scenarios. Due to the chirality of a large number of life-sustaining molecules, many parameters of the reaction kinetics involving these chiral molecules, such as the reaction rate and the reagents concentrations, could be tracked by monitoring the optical activity of the substrate and/or product molecules. However, the optical activity of photosensitive biomolecules does not allow traditional laser-based real-time measurement due to the vulnerability of their biochemical properties under high-intensity light regimes. Here we introduce a real-time tracking technique of the sucrose hydrolysis reaction based on two-photon coincidence measurements. The two-photon source is generated based on a spontaneous parametric down-conversion process. During the reaction, the kinetic parameters are obtained by the real-time measurement of the change of the polarization of the photons when operating at extremely low-light regimes. Compared with single-photon counting measurements, two-photon coincidence measurements have higher signal-to-noise ratios and better robustness, which demonstrates the potential value in monitoring the photosensitive biochemical reaction processes.

Highlights

Enzymes, and small energy metabolism molecules are chiral in structure, with their chirality leading to a rotation of the plane of the in-coming polarized light, which is the optical activity of the chiral molecules
The adoption of N00N states could improve the resolution of the measured phase angle [2,25], the method reported in this article still has its own advantages: (1) it has low requirements on the pump light source, the quality of the nonlinear crystal and light path adjustment in contrast to an interferometry approach
To obtain a higher coherent contrast N00N state, the spatial walk-off of the generated spontaneous parametric down conversion (SPDC) photons in the crystal has to be precisely compensated and single-mode fibers should be used to improve the light mode based on our existing light source; (2) it’s less affected by the power, frequency, and modestability of the light source, as well as changes in ambient temperature

Summary

Introduction

Enzymes, and small energy metabolism molecules are chiral in structure, with their chirality leading to a rotation of the plane of the in-coming polarized light, which is the optical activity of the chiral molecules. Molecules with different optical activities can be used to identify the 3D structures of these molecules [1]. By tracking the change of the reagents optical activity, real-time measurement of the kinetic parameters of biochemical reaction processes, in which chiral molecules participate, can be performed. Long-term monitoring of biochemical reaction processes is often required, the use of optical activity tracking methods in industrial applications is a meaningful technique. Since many biomolecules are photosensitive, long-time exposure to a traditional polarized laser beam will inevitably affect the reaction process [3,4]. In the low-light regime, the fluctuation of the photon flux and the influence of environmental noise become more relevant, quantum correlation measurements can be applied to effectively eliminate the influence of environmental noise [8,9,10,11], thereby improving the signal-to-noise ratio of the measurement

Methods

Results

Conclusion