Recent Advances on Sorting Methods of High-Throughput Droplet-Based Microfluidics in Enzyme Directed Evolution

Area of Science:

• Biotechnology
• Chemical Engineering
• Molecular Biology

Background:

• Droplet-based microfluidics offers low-cost, high-throughput platforms for enzyme directed evolution (DE).
• The efficiency of microfluidic DE heavily relies on droplet sorting methodologies, which can be either labeled or label-free.
• Current labeled methods like Fluorescence-Activated Droplet Sorting (FADS) have limitations in enzyme scope.

Purpose of the Study:

• To comprehensively review droplet sorting methods used in microfluidic enzyme DE.
• To highlight recent advancements and applications of these sorting techniques.
• To discuss the advantages and challenges of various methods for future enzyme DE development.

Main Methods:

• Comprehensive literature survey of droplet sorting techniques in enzyme DE.
• Categorization of methods into labeled (FADS, Absorbance-Activated Droplet Sorting - AADS) and label-free (Electrochemical-Based Droplet Sorting - ECDS, Mass-Activated Droplet Sorting - MADS, Raman-Activated Droplet Sorting - RADS, Nuclear Magnetic Resonance-based Droplet Sorting - NMR-DS).
• Analysis of recent enzyme DE cases utilizing microfluidic sorting.

Main Results:

• Identified FADS and AADS as primary labeled sorting methods.
• Detailed label-free sorting methods including ECDS, MADS, RADS, and NMR-DS.
• Highlighted successful generation of novel enzymes and variants using microfluidic DE in the last five years.

Conclusions:

• Label-free sorting methods have the potential to significantly broaden the applicability of microfluidic DE.
• Each sorting method presents unique advantages and challenges that influence its suitability for specific enzyme DE applications.
• Further development in label-free sorting is crucial for advancing enzyme discovery and engineering.