Microfluidic Devices for Monitoring the Root Morphology of Arabidopsis Thaliana in situ

A Dual-Channel Microfluidic Chip for Single Tobacco Protoplast Isolation and Dynamic Capture

Protoplasts are widely used in gene function verification, subcellular localization, and single-cell sequencing because of their complete physiological activities. The traditional methods based on tissues and organs cannot satisfy the requirement. Therefore, the isolation and capture of a single protoplast are most important to these studies. In this study, a dual-channel microfluidic chip based on PDMS with multi-capture cavities was designed. The design theory of the dual-channel microfluidic chip's geometry was discussed. The capture mechanism of the single cell in a dual-channel microfluidic chip was studied by simulation analysis. Our results showed that a single polystyrene microsphere or tobacco protoplast was successfully isolated and trapped in this chip. The capture efficiency of the chip was 83.33% for the single tobacco protoplast when the inlet flow rate was 0.75 μL/min. In addition, the dynamic capture of the polystyrene microsphere and tobacco protoplasts was also presented. Overall, our study not only provided a new strategy for the subsequent high throughput single protoplast research, but also laid a theoretical foundation for the capture mechanism of the single cell.

The Cell Wall Regeneration of Tobacco Protoplasts Based on Microfluidic System

The cell wall, serving as the exoskeleton of plants, is naturally a barrier to resist external stresses. Protoplasts can be obtained by dissolving the cell walls of plant cells without damaging the cell membrane, and are widely used in the rapid propagation, transgenic breeding, and somatic hybridization of plants. However, to regenerate the cell wall is a precondition for cell division. Therefore, to study the culture condition and influencing factors during the cell wall regeneration of protoplasts is vital. Traditionally, culture medium is used to cultivate protoplasts, but it has some disadvantages. Herein, a microfluidic system with crossed channels was constructed to isolate and cultivate the protoplasts of tobacco. Then, the cell wall regeneration of the tobacco protoplasts was also studied based on this microfluidic system. It was found that, compared with the control, benzo-(1, 2, 3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) could accelerate the regeneration of the cell wall, while Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) could inhibit the regeneration of the cell wall within 24 h. To conclude, this study demonstrated that a crossed microfluidic chip could be an effective tool to study cell wall regeneration or other behavior of plant cells in situ with high resolution. In addition, this study revealed the rate of cell wall regeneration under BTH and Pst DC3000 treatment.

Microfluidics for understanding model organisms

New microfluidic systems for whole organism analysis and experimentation are catalyzing biological breakthroughs across many fields, from human health to fundamental biology principles. This perspective discusses recent microfluidic tools to study intact model organisms to demonstrate the tremendous potential for these integrated approaches now and into the future. We describe these microsystems' technical features and highlight the unique advantages for precise manipulation in areas including immobilization, automated alignment, sorting, sensory, mechanical and chemical stimulation, and genetic and thermal perturbation. Our aim is to familiarize technologically focused researchers with microfluidics applications in biology research, while providing biologists an entrée to advanced microengineering techniques for model organisms.

Real-time tracking of root hair nucleus morphodynamics using a microfluidic approach

Root hairs (RHs) are tubular extensions of root epidermal cells that favour nutrient uptake and microbe interactions. RHs show a fast apical growth, constituting a unique single cell model system for analysing cellular morphodynamics. In this context, live cell imaging using microfluidics recently developed to analyze root development is appealing, although high-resolution imaging is still lacking to enable an investigation of the accurate spatiotemporal morphodynamics of organelles. Here, we provide a powerful coverslip based microfluidic device (CMD) that enables us to capture high resolution confocal imaging of Arabidopsis RH development with real-time monitoring of nuclear movement and shape changes. To validate the setup, we confirmed the typical RH growth rates and the mean nuclear positioning previously reported with classical methods. Moreover, to illustrate the possibilities offered by the CMD, we have compared the real-time variations in the circularity, area and aspect ratio of nuclei moving in growing and mature RHs. Interestingly, we observed higher aspect ratios in the nuclei of mature RHs, correlating with higher speeds of nuclear migration. This observation opens the way for further investigations of the effect of mechanical constraints on nuclear shape changes during RH growth and nuclear migration and its role in RH and plant development.