Designing Microfluidic Devices for Drug Diffusion Testing
Posters in Parliament 2026
Designing Microfluidic Devices for Drug Diffusion Testing
Rindhiya Vishnu Shankar
Abstract
Diffusion, a seemingly simple concept that underpins many pharmacological processes, remains challenging to evaluate quantitatively. Whilst conventional diffusion testing methods are widely used, they can be expensive, time-consuming, and limited in reproducibility. Microfluidic lab-on-chips have recently emerged as viable alternative platforms for studying controlled diffusion at physiologically relevant length scales, while using minimal sample volumes. Within these systems, hydrogels have been increasingly used in toxicology studies due to their ability to tune solute transport.
Early-stage designs of the 3D-printed microfluidic lab-on-chips incorporate a three-channel design that comprises a source and sink channel, separated by a central hydrogel channel, functioning as a selective diffusion interface. Building on previously reported hydrogel-partitioning designs, this study focuses on improving performance and scalability through simplified fabrication and the use of commercially available photopolymer resins. The chips were designed using CAD tools and fabricated via digital light processing (DLP) 3D printing, followed by post-curing and bonding to APTES-coated glass slides.
Several design iterations, incorporating pillar capillary and phase-guide hydrogel barrier features, were tested to investigate hydrogel confinement and diffusion behaviour. Both fibrin-based hydrogels and organo-hydrogels were tested to observe differences in meniscus formation and diffusion behaviour. Dyed buffer solutions were used to visualise the flow across the hydrogel barriers. The research identified practical user limitations of the design, especially when sealing the printed chips to the glass slide. The insights gained from the limitations were used to design a more user-oriented microfluidic platform for hydrogel-based diffusion studies that lab technicians can easily use.
Research Explanation
Figuring out how much and how quickly medicine diffuses into the body is crucial when evaluating the safety and efficacy of drug dosages. If diffusion is too slow, treatment may be ineffective and if it is too fast, it can increase the risk of side effects. Despite it being a seemingly simple and fundamental concept, it is difficult to measure accurately in laboratory settings especially for different parts of the body. Traditional testing methods are often costly, time-consuming, and difficult to reproduce, limiting their usefulness in early-stage drug development.
This research investigates a more efficient and accessible alternative using miniaturised lab-on-a-chip devices. These small, 3D-printed platforms can be used to replicate diffusion by using very small volumes of fluid, reducing cost and experimental waste while improving control and repeatability. A central feature of the device is hydrogel, a soft, tissue-like material that acts as a controlled diffusion barrier and can be tuned to better represent various biological environments in the body.
The study designed and tested multiple chip designs using commercially available materials and straightforward fabrication methods. Different hydrogels were evaluated to understand how they influence diffusion behaviour, using coloured solutions to visualise the flow of diffusion . The research identified practical challenges faced by laboratory users, leading to a design of a more user-friendly and scalable platform for diffusion testing in drug development and toxicology.