Advanced Sensors
Gas Detection
One of the main research areas within the MiNa lab is the development of new gas sensors and detection techniques, with the ultimate goal of achieving artificial olfaction – a sensing methodology of similar functionality to the human olfactory system. In the past, much of our work was focused on enhancing the selectivity of a sensor through the addition of modified microchannels. The microchannel modifications included features such as micropillars, graphene quantum dots, and various coatings, all used to change the surface properties of the channel and create more variation between the diffusion of different molecule types. These microchannel-modified sensors, in combination with machine learning-based post-processing, resulted in the selectivity of a basic sensor to be increased by over 120%.
In addition to universal methods of improving sensor response we also aim to increase sensor selectivity and sensitivity through sensing layer adaptation. With the addition of novel materials, such as specifically tailored metallic catalysts or bio-inspired molecularly imprinted polymers (MIPs), we can greatly improve the sensing response of a sensor to a specific analyte of interest. MIPs are synthetic receptors that are designed to trap a specific target molecule, similar to how antibodies and antigens are paired in the human body. A polymer is imprinted with a desired molecule, resulting in the polymer having molecule-specific “holes” that may be used as future binding sites. This MIP is then coated onto the sensing layer, increasing the sensor’s selectivity. We’re applying this technology to aid in the detection of analytes that are traditionally difficult to detect, such as THC (the main psychoactive component in cannabis) due to its molecular similarity to CBD (one of the non-psychoactive components in cannabis) for use in impairment recognition.
Liquid Detection/Microplastics
We are also exploring improved methodologies to detect compounds in liquid samples such as bodily fluids like saliva and environmental water samples. While we are incorporating similar techniques to those used in gas sensing, such as the use of MIPs, we are also investigating detection methods using aptamers for biosensing and triboelectric-based methods for microplastics detection. Aptamer-based sensing, similar to MIP-based sensing, is biomimetic, as aptamers are commonly referred to as “chemical antibodies”. They are short ligands that can be designed to specifically bind to target molecules. Although they have many similarities with MIPs, they have higher binding specificity for certain entities, namely proteins and cells, which can be advantageous for biosensing applications. Triboelectricity is electrical charge that develops due to friction. This charge or charge transfer can be quantified and recorded, allowing for the materials involved to act as a sensing system. For materials such as microplastics that have an opposing electron affinity when compared to glass, the triboelectric effect can be used within microchannels on glass slides to quantify material concentration within liquid samples.
Drug Delivery
Microencapsulation
Many drugs require protection, whether it be from the environment they encounter during the manufacturing and transportation process, or the harsh conditions within the gastrointestinal tract. Microencapsulation is a method that has proven to be effective for the protection of a variety of cargo in differing circumstances. We use lab-made microfluidic systems to generate microcapsules for different applications:
- Optimization of Medication Delivery for Aquatic Life – We are exploring ways to improve the bioavailability, efficacy, and ease of use of the drugs commonly used to treat salmon in salmon farms. By tailoring the microcapsule shell, structure, pH resistance, and buoyancy, we can develop a fish food additive that will optimize the delivery of the medication to the fish, reducing the amount of drug required. This benefits not only the manufacturer, but also the environment as the medication doesn’t end up on the ocean floor and/or consumed by other unintended creatures.
- Multi-Shell Microcapsule for Targeted Delivery – Many drugs and bioactive compounds have an ideal delivery site in the gastrointestinal tract, but due to the harsh environment of the stomach, large doses or specialized coatings are often required to protect the cargo during its journey. By creating microcapsules with multiple layers, two materials can be distributed at different parts of the GI tract and can be triggered from a variety of differing conditions – including pH and enzymatic states. This allows for the precise development of drug-release states as well as the possibility of staggered drug release from the same capsule. We are partnered with a research group at UBC to effectively encapsulate bacterial biosensors for the detection of different states in the gut based on fluorescence output.