Special Issue on the Development of Microfluidic Devices for Medical Applications

Microfluidics refers to the science of handling fluids in microstructures and has been widely used in the medical field to miniaturize conventional drug delivery systems, bioassays, and diagnostics. Microfluidic technology provides improved mass transfer, mixing time, and heat exchange; precise flow control; higher precision; greater reliability and sensitivity; portability; and ease of production. It also reduces reagent quantity, shortens bioassay times, and helps in reducing the overall cost of the drug development process.

This Special Issue aimed to collect and present breakthrough research addressing technical challenges in developing and manufacturing microfluidic devices for medical and diagnostics applications, including drug discovery and delivery; micropumps and microvalves; bioMEMS; microneedles; integrated on-chip sensors; lab-on-chip (LOC) and organ-on-chip (OOC); biomedical microfluidic devices; manipulation of biofluids and cells; micro total analysis system (mTAS); bioassays; diagnostics and theranostics; manipulation of biomolecules and biofluids; and point-of-care (POC) testing.

A total of five papers (three research papers and two review papers) in various microfluidics fields are presented in this Special Issue. Delavari et al. [1] reported novel biodegradable starch/PVA-based films with nano-sized zinc-oxide particles for wound-dressing applications. The new starch-based materials exhibit interesting and promising physical and chemical properties, including solubility, gel fraction, fluid absorption, biodegradability, surface morphology, and mechanical properties. Furthermore, the in vitro analysis of the antibacterial activity demonstrated that this dressing material effectively inhibited the growth and penetration of bacteria such as Escherichia coli and Staphylococcus aureus. Durasiewicz et al. [2] designed and characterized original normally open microvalves made of biocompatible materials. These diaphragm-type piezoelectric valves with multiple valve seat trenches show low leakage rates in the closed state and high flow rates in the open state, making them suitable for lab-on-chip and other medical applications. Bußmann et al. [3] developed and characterized a precise 5 × 5 mm² diaphragm silicon micropump. This self-priming piezoelectric pump has a dosing precision in both basal and bolus modes similar to commercially available insulin pumps. The device has other attractive features for drug delivery, including high blocking pressure, bubble tolerance, and low power consumption. Monjezi et al. [4] reviewed the applications of microfluidic chips in anti-cancer drug screening and provided a systematic categorization of these systems as a function of sample size and combination of drug screening. Current limitations of microfluidic platforms for drug screening are also discussed, and possible solutions to these problems are proposed. Chappel [5] analyzed the different technologies of passive constant flow regulators dedicated to microfluidic and medical applications. Without external control or energy consumption, these devices deliver a constant flow regardless of pressure variations. The progress made in the development of these flow control valves over the past three decades is examined with a detailed description of their operating principle, manufacturing methods, performance, and potential applications.

Submissions for this Special Issue are now closed. Further research in the field of microfluidic technologies dedicated to medical applications continues to address the challenges of miniaturization of conventional drug delivery systems, bioassays, and diagnostics.