Dependency of hydrogel membrane pores on membrane pressure and concentration: Numerical and experimental investigations

Control of pore opening is a valuable contribution to ensure filtration and separation of particles and cells of different sizes. These can be, e.g. blood cells with their cell distribution width, which is typically measured in the Complete Blood Count. In the current work, we investigate hydrogel pores made of pNIPAAm with swelling and de-swelling capabilities. They react to variations in ethanol concentration. Additionally, we analyze the effect of microfluidic pressure on membrane pores. Furthermore, the influence of the gel volume for cross-shaped pores is shown. For this purpose, experimental and numerical investigations are performed. An analogy model for the swelling behavior based on the Temperature-Expansion-Model from our previous work and a neo-Hookean material description is applied to describe swelling and mechanical deformation of the pores. Simulation results show a negligible influence to the pore bending in the specified pressure range. In the experiments, only a slight change in the pore area is observed under pressure variation. Nonetheless, there is a very good agreement between numerical and experimental results. The current investigations show the potential for the mechanical description of hydrogel pores for their further geometric optimization.

Automated summary

This study investigates the control of hydrogel pores with swelling and de-swelling capabilities, and analyzes the effects of microfluidic pressure and gel volume on the pores. Experimental and numerical investigations show that the swelling behavior can be described using a temperature expansion model and a neohookean material description, and the bending influence on the pores under pressure can be negligible. The results have good agreement between numerical and experimental results, demonstrating the potential for geometric optimization of hydrogel pores.