Periodic Reporting for period 1 - VORTEX SENSOR (Vortex microflow inducer that enables detection of ultra-low concentrations of species in sensors)
Reporting period: 2024-03-01 to 2025-08-31
The release of over 100,000 chemicals into the global environment in 2018 has led to significant water pollution, causing acute and chronic toxicity in aquatic organisms, loss of habitats, biodiversity, and human diseases. Current methods for detecting water pollutants are expensive, time-consuming, and not portable
The VORTEX SENSOR project aimed to address these challenges by developing a novel microfluidic device, the 'vortex microflow inducer,' integrated with sensor chips. This device enhanced mass transfer and detection sensitivity through acoustic streaming, reducing analysis time and improving detection limits. The goal was to create a cost-effective, point-of-testing biosensor capable of detecting low concentrations of pollutants in under 15 minutes. This innovation significantly lowers the costs of water quality analysis and support environmental control, wastewater management, and aquaculture.
The project validated a Minimum Viable Product (MVP), conducted market analysis, and developed a business strategy to ensure commercial viability. By leveraging novel mixing technology, VORTEX SENSOR aimed to set a new paradigm in water analytics, making high-sensitivity, low-cost water quality monitoring accessible to all.
The VORTEX SENSOR project aimed to address these challenges by developing a novel microfluidic device, the 'vortex microflow inducer,' integrated with sensor chips. This device enhanced mass transfer and detection sensitivity through acoustic streaming, reducing analysis time and improving detection limits. The goal was to create a cost-effective, point-of-testing biosensor capable of detecting low concentrations of pollutants in under 15 minutes. This innovation significantly lowers the costs of water quality analysis and support environmental control, wastewater management, and aquaculture.
The project validated a Minimum Viable Product (MVP), conducted market analysis, and developed a business strategy to ensure commercial viability. By leveraging novel mixing technology, VORTEX SENSOR aimed to set a new paradigm in water analytics, making high-sensitivity, low-cost water quality monitoring accessible to all.
In the first part of the project, bulk acoustic waves (BAWs) were generated using a silicon-based chip. During the development of the BAW setup, several disadvantages became apparent. Based on the typical streaming pattern with four vortices, the BAWs can only enhance mass transport through the sensor from half the height of the flow cell, thereby limiting the system’s overall improvement. Silicon shows several disadvantages (expensive, hard sealing, etc.). Alternatively, Eckart streaming relies on the dissipation of acoustic energy within the bulk of the liquid. This concept was tested, and particle mixing was observed. However, the process faced challenges related to limited reproducibility and efficiency.
Sharp-edge streaming was the next pursued approach. With a well-designed geometry, the entire liquid flowing above the sensor can be actively mixed. It is not frequency and dimension dependent, it is cheap and easy for reversible sealing.
High-power acoustic streaming significantly enhances mass transfer, but requires active cooling because of the PZT temperature rising. We integrated a closed-loop temperature control system into the acoustofluidic setup. A thermocouple interfaced with an Arduino microcontroller regulated a Peltier module, maintaining the system at target temperature. The system could avoid a temperature rise when a voltage up to 150 Vpp was applied. If needed a more powerful Peltier element can be used to improve this performance further.
Alternative designs were used to enhance mixing. Transparent chips, glass rectangles were used to visualize and analyze acoustic streaming.
In some designs streaming vortices could be generated across a wide range of frequencies, and the operating regime had limited influence (single vs sweep).
DNA bonding was used as a test mechanism and enhance with acoustic mixing. Acoustic waves were generated up to 65 V. A positive impact was observed during the experiments.
In theory, enhancing mass transport can only improve diffusion-limited systems. Whether a system is diffusion-limited depends on its kinetics: if diffusion is faster than reaction, system is reaction-limited. Conversely, the system is diffusion-limited.
In the tested system, we hypothesize that DNA diffusion was in given cases faster than its reaction. Even though the setup could not be consistently tested on a diffusion-limited reaction, the potential of the technology was clearly demonstrated. The ability to actively mix liquids for sensing enhancement was developed, and the chip geometry was optimized.
Based on these findings, the final phase of the project focused on identifying application domains where the technology offers a clear advantage, specifically, systems known to operate in a diffusion-limited regime. This project led to several (at this stage confidential) follow-up proposals targeting high impact fields wherein detection and enhanced mass transport is critical.
Sharp-edge streaming was the next pursued approach. With a well-designed geometry, the entire liquid flowing above the sensor can be actively mixed. It is not frequency and dimension dependent, it is cheap and easy for reversible sealing.
High-power acoustic streaming significantly enhances mass transfer, but requires active cooling because of the PZT temperature rising. We integrated a closed-loop temperature control system into the acoustofluidic setup. A thermocouple interfaced with an Arduino microcontroller regulated a Peltier module, maintaining the system at target temperature. The system could avoid a temperature rise when a voltage up to 150 Vpp was applied. If needed a more powerful Peltier element can be used to improve this performance further.
Alternative designs were used to enhance mixing. Transparent chips, glass rectangles were used to visualize and analyze acoustic streaming.
In some designs streaming vortices could be generated across a wide range of frequencies, and the operating regime had limited influence (single vs sweep).
DNA bonding was used as a test mechanism and enhance with acoustic mixing. Acoustic waves were generated up to 65 V. A positive impact was observed during the experiments.
In theory, enhancing mass transport can only improve diffusion-limited systems. Whether a system is diffusion-limited depends on its kinetics: if diffusion is faster than reaction, system is reaction-limited. Conversely, the system is diffusion-limited.
In the tested system, we hypothesize that DNA diffusion was in given cases faster than its reaction. Even though the setup could not be consistently tested on a diffusion-limited reaction, the potential of the technology was clearly demonstrated. The ability to actively mix liquids for sensing enhancement was developed, and the chip geometry was optimized.
Based on these findings, the final phase of the project focused on identifying application domains where the technology offers a clear advantage, specifically, systems known to operate in a diffusion-limited regime. This project led to several (at this stage confidential) follow-up proposals targeting high impact fields wherein detection and enhanced mass transport is critical.
The project achieved results that go beyond the current state of the art in acoustofluidic mixing for sensor enhancement. By transitioning from BAW methods to sharp-edge streaming, the team overcame limitations in mixing efficiency and system complexity. Sharp-edge streaming enabled full-volume liquid mixing above the sensor, independent of frequency and geometry constraints, while also offering cost-effective and reversible sealing solutions. The integration of a closed-loop temperature control system allowed stable operation at high acoustic power (up to 150 Vpp), mitigating thermal issues typically associated with piezoelectric transducers. Additionally, the use of transparent chip designs facilitated direct visualization of streaming patterns, and mixing was shown to be robust across a wide frequency range. Although consistent testing on diffusion-limited reactions was not possible with the assay, preliminary DNA bonding experiments demonstrated enhanced mass transport, validating the concept. These innovations pave the way for targeted applications in domains where diffusion-limited kinetics are critical, leading to several confidential follow-up proposals in high-impact fields.