Biocompatible magnetic nanocomposite microcapsules as microfluidic one-way diffusion blocking valves with ultra-low opening pressure

Abstract

A one-of-a-kind biocompatible magnetic nanocomposite microcapsule is developed as an in-line passive valve that can be integrated with micropumps and microfluidics. The magnetic nanocomposites act as the core for building a valve that utilizes the magnetic force attraction for sealing the microfluidic channels. The nanocomposites, molded with commercial microtubings, are prepared by incorporating Fe3O4 nanoparticles into polyethylene-glycol (PEG). Parylene-C provides a flexible, biocompatible shell and moisture barrier for the microcapsule that enables deformation and sealing to the microfluidic channel wall. The highly customizable valve design offers easy scalability, and simplicity for integration into microfluidic systems. The presented magnetically-responsive microcapsule demonstrates reliable performance as a passive one-way valve that exhibits unique features and capabilities including effective flow-rectification with steady flows, extremely low leakage flows from backpressures at a rate of 4.7 nL/min kPa−1, successfully block 99.96% of the diffusion, and extremely low inlet flow opening pressure of 2.1 kPa.

On the paradigm of Hierarchically Structured Materials, in conjunction with the Virtual Special Issue on Functional Materials

“…Similar multilayered 200-500 nm nanoparticles with Fe oxide cores produced using liquid phase methods were designed to act as sorbents for the removal of dyes [19], biocompatible micro-fluid devices (valves and filters) with potential for blood vessel manipulations [20], photocatalysis [21]. Conversely, nanoparticles with soft / porous core and hard shells of similar dimensions were designed for heat and energy related applications (energy storage and insulation) [22][23][24].…”

Magnetic Polymers for Magnetophoretic Separation in Microfluidic Devices

“…Thus, a large panel of microfluidic functionalities for fluid sample handling has emerged employing composite polymers, such as micro-valves, micro-pumps, or micro-mixers for microfluidic flow control [36,40,[42][43][44][45][46][47]; dynamic artificial cilia [41,[48][49][50]; and reversible microchannel bonding [51]. Ferrofluids were also explored for actuation in microfluidic systems [52][53][54][55].…”

A Wirelessly Controlled Scalable 3D-Printed Microsystem for Drug Delivery

“…However, most reservoirs are made of elastomeric membranes integrated into pumping mechanisms that deform due to the extraction of fluid due to pumping, resulting in a restoring force, which tends to restore the membrane to its original shape. After pumping has stopped, the restoring force results in a non-negligible backward flow, which is typically counteracted by employing either a normally closed fluidic channel or check valves [27,31,32]. This restoring force prevents the reservoir from being integrated into normally open pumps due to its dramatic effect on the pumping efficiency.…”