Recently, Prof. Tianrui Zhai's group at Beijing Institute of Technology (BIT) proposed a technique to determine enantiomeric excess (ee) based on optofluidic microlaser singularity (EP). The technique measures the chirality of enantiomers by utilizing the polarization of EP-induced unidirectional echo wall mode (WGM) laser and detects the enantiomeric concentration by the laser wavelength, which allows for the direct determination of ee under unknown concentration conditions, which is not possible with conventional methods.
Fig. 1. a) Schematic diagram of an optofluidic microlaser near the singularity point (EP) for determination of enantiomeric excess. b) WGM-enhanced spin effect. c) Intensity variations of transverse magnetic (TM) and transverse electric (TE) modes induced by rotation of laser polarization. d) Intensity variations of transverse magnetic (TM) and transverse electric (TE) modes induced by rotation of laser polarization.
In modern medicinal chemistry, purification and analysis of chiral drugs are crucial. The enantiomers in chiral molecules (i.e., the left- and right-handed forms of the molecule) may have very different pharmacological activities. Therefore, accurate determination of ee, i.e., enantiomeric purity determination, is essential for drug safety and efficacy. Conventional methods usually require two different techniques to measure chirality and concentration, respectively, a cumbersome and inefficient process. The present study is innovative in that it provides a single technique to accomplish both tasks simultaneously. In addition, traditional assays often require expensive equipment and large amounts of chemical reagents with limited sensitivity.
Recently, Prof. Tianrui Zhai's group at Beijing Institute of Technology (BIT) proposed a technique based on photofluidic micro-laser EP determination of ee. The core of this technology is a WGM-based optofluidic micro-laser, which induces unidirectional lasing by EP, enabling the laser to sense both chirality and concentration changes of enantiomers. This two-parameter assay not only simplifies the experimental steps, but also significantly improves the sensitivity and accuracy of the assay.
The results show that this new method performs well in the detection of chiral compounds at various unknown concentrations. Especially in the determination of important bioactive molecules - such as amino acids and sugars. In addition, this technology has achieved remarkable success in reducing reagent consumption and simplifying the operational process. While conventional methods typically use reagent volumes on the order of milliliters, this method consumes only microliters of reagent, reducing sample consumption by three orders of magnitude. This has a positive effect on both experimental costs and environmental protection.
Fig. 2. Chirality and concentration detection of enantiomers of eight essential amino acids.
This study not only provides new perspectives in theory, but also shows great potential in practical applications. This new method is expected to play an important role in the fields of drug development, biochemical detection and environmental monitoring. In summary, this study not only provides a new method for chiral analysis, but also opens up a new field of biochemical chiral detection using optofluidic microlasers. With the further development and application of this technology, more breakthroughs are expected to be realized in medicinal chemistry and wider scientific fields.
