Capillary stop valve actuation by thermo-pneumatic- pressure for lab-on-chip systems

Abstract

A novel method is presented for triggering a robust capillary stop valve fabricated in silicon using the thermal expansion of trapped air bubble ( with a footprint of just 300 μm x 320 μm ) as the actuation element. A heating element on the backside of a bubble trap chamber is utilized for thermal expansion of the air bubble. A voltage pulse of around 6V, the capillary barrier, around 1400 Pa was easily breached. A non-dimensionalized model has been developed using equivalent circuit model to describe the complex thermal/hydraulic behavior of the system. The trapped gas bubble temperature is input as a function of time in the model. A thermal finite element-based simulation is conducted to determine the gas temperature from the experimentally measured heater temperature. The model results are validated against experiments to aid in characterizing the dynamics of the problem.

Capillary-driven microfluidics: impacts of 3D manufacturing on bioanalytical devices

“…20 Unknown effects of Fig. 6 Assisted actuation of capillary valves based on: (a and b) manual (mechanical push) actuation; 24,30 and (c) thermo-pneumatic-pressure, 31 it was filled with the capillary flow and waiting to be triggered, a voltage was provided to heat up and expand the trapped air bubble, and valve is actuated by breaching the capillary barrier and capillary flow commences in the microchannel. "Reprinted/adapted with permission from: (c) © 2021 Springer Nature."…”

“…Microheaters have also been used to activate fluid flow. Barman et al 31 proposed a capillary valve that was actuated by heating up the trapped air to breach the capillary pressure barrier (Fig. 6c).…”

A 3D Capillary-Driven Multi-Micropore Membrane-Based Trigger Valve for Multi-Step Biochemical Reaction

“…In these 2D devices, capillary channels and valves mainly included burst pressure valves and trigger valves (Figure 1a) with the triggering agent. Different analytical and numerical models have been reported to study the influence of channel shape, surface characteristics, and fluid characteristics on them [17][18][19][20][21]. However, due to the 2D limitation, the holding time of these valves was usually less than 5 min [22], restricting the time for the user to pre-load the liquid sample and their operational applicability.…”

Modeling of Acoustic Vibration Theory Based on a Micro Thin Plate System and Its Control Experiment Verification

“…Nevertheless, the determination of effective vibration frequency for a vibration system is of great significance, as not all vibration frequencies can be used for target manipulation. Intriguingly, acoustic vibration of the thin plate has a wide application prospect including the manipulation based on chip [1][2][3], the culture of cells and tissues [4,5], particles forming, self-assembly, classification of particles, particle movement and other promising micro-nano manipulations [6][7][8][9][10][11]. Those are difficult to be accomplished by directly applying external mechanical force because of the micro-nano size of the manipulation object and the high-precision requirements for the hardware platform [12].…”