State-of-the-art review on the application of microfluidics in biogeotechnology

As a popular research direction in the interdisciplinary fields of bioengineering and geotechnical engineering, biogeotechnology shows the potential advantages in environmental friendliness, spontaneity, and low-carbon. More than 80% of soil microorganisms live in the micropores of geo-materials. The environment in the micropores has an impact on microbial activity, while the traditional geotechnical testing methods cannot achieve real-time analysis of microbial activity. In recent years, microfluidic techniques are gradually applied in biogeotechnology. It can visualize and manipulate microbial activity in micro and nano-scale microchannels, providing a controllable in-situ monitoring method for investigating the microscopic mechanisms of biogeotechnology. Microfluidic can simulate engineering environment by changing the type and function of microfluidic chips. This paper reviews the current development of microfluidic techniques in biogeotechnology, involving microbial behavior, reaction flow, and biomineralization. The aim is to reveal the significance of microfluidic techniques in studying the micro-mechanisms of biogeotechnology, providing evidence for macroscopic experiments and promoting the application of biogeotechnology in practice. Besides, the limitations of microfluidic techniques in biogeotechnology are summarized. The future development of microbial microfluidic platform is proposed. The paper also provides the guidelines of using microfluidic to study the microorganism activity in environmental science, energy science, and materials science.