Sky’s the limit for ‘Lab-on-a-Chip’ creator

Known for his sharp wit and steely determination, Soil CRC PhD student Reuben Mah is a self-proclaimed perfectionist who strives for continuous improvement. His endless curiosity and process-focussed approach were ingrained from an early age.

“I was born in Malaysia and raised in a family environment that strongly encouraged critical thinking and questioning – there was never a stupid question,” Reuben said. “I was taught to pay attention to process and effort, rather than results alone. I learnt that the correct process will invariably produce consistent results.”

Reuben continues to apply this approach to every aspect of his life, from his studies and work to his sporting endeavours.

“No best efforts are without failures or problems, and I have managed them well using the lessons I’ve learnt. I know that the outcome of any problem will depend on my attitude towards it,” he said.

Reuben also credits his family for cultivating an unwavering curiosity and interest in unravelling complicated subjects. It was his desire to achieve a deeper understanding of food security and find sustainable solutions that led him to take on tertiary studies in agricultural science.

“Food insecurity has been gradually escalating over the years, but seldom captures the media headlines as much as breakthroughs in medicine and science and technology,” he said.

“After completing the first two years of a bachelor’s degree in the rudiments of agriculture science, I decided to focus on the foundation of crop cultivation – the soil.” Reuben said this is where his childhood lessons in getting the process right came to bear.

“There are significant shortcomings in the current analysis of soil macronutrients using laboratory methods to determine soil fertility,” he said. “The cost of laboratory-based tests can be prohibitive, and the results outdated due to the volatility of the macronutrients.”

“This is analogous to the costs and delays in determining illness in the human body, which can have deleterious consequences.”

So, Reuben inferred, there needed to be a process, in the form of a tool, to quickly determine soil fertility and render the appropriate amount and type of fertiliser as an intervention.

“The final years of my tertiary education was focused on soil studies which culminated with the investigation of using a 3D-printed microfluidic device as a low cost, portable and in-field device to determine the macronutrients in the soil with real-time measurements,” he said.

Reuben’s investigations addressed the shortcomings of the current laboratory methods, and his findings provided a launch pad for the next phase of development. 

“When a Soil CRC PhD scholarship opportunity arose, I immediately jumped on it,” Reuben enthused. “It was the perfect chance for me to advance the development of the microfluidic device for soil fertility detection and bring the concept to fruition.” 

Reuben explained the objective of his PhD research was to develop a functional microfluidic device capable of measuring the soil macronutrients of nitrates, phosphorus and potassium ions.

“Such a device must be capable of emulating the complex laboratory processes by functioning as a ‘Lab-on-a-Chip’ that is also able to immobilise reagents within, and enable mixing of solutions to deliver accurate and reliable real-time results using chromatic reaction RGB analysis. The other must-haves include portability for infield use, simplicity of use and low-cost,” he said.

Through his PhD, Reuben successfully developed a functional 3D-printed microfluidic device for measuring soil macronutrient levels by producing a chromatic reaction, which can be measured using RGB analysis. This is an achievement he is rightly proud of, and a big step towards achieving his ultimate goal.

Reuben said the imminent delivery of the chromatic measurement using a smart phone app created by our project partners at the University of Newcastle is the final step before teaming with a commercial partner to make the device accessible to farming communities.

“The device will provide real-time measurements at low cost to enable farmers to perform multiple replicates of measurements as often as required,” he said. “Quick fertiliser interventions will ensure sustainable soil fertility, providing higher crop outputs and yield for improved earnings.”

With his PhD thesis now submitted, Reuben can look back and reflect on his experience.

“In hindsight, my PhD project was truly enjoyable, and I am incredibly grateful for the opportunity. It challenged my intelligence, knowledge, and resilience, especially after long hours spent performing numerous iterations of the same and different experiments,” he said.

“This experience has honed my critical thinking, analytical and problem-solving skills, enhanced my resilience to work stress, and increased my ability maintain emotional composure when handling failures and problems.”

Maintaining his ever-positive attitude towards problem solving, Reuben said he was able to quickly step away from the problems to get an elevated view of the situation. This gave him the clarity he needed to think outside the box, improvise, and adapt to seek innovative solutions.

“I also really valued the opportunity to get out of the lab and head into the field to get first-hand feedback from representatives of the farming community,” Reuben said. “It enabled me to understand their needs and expectations, which informed device considerations and design.”

Reuben highlighted his deep appreciation for the support of his University of Tasmania supervisors, Professor Michael Breadmore, Associate Professor Richard Doyle, Dr Fernando Alejandro, and Dr Marcus Hardie, who kept him on track with their guidance, words of encouragement and motivation.

“I’m grateful to everyone involved in my research project, from those who provided technical support at the University of Tasmania and the University of Newcastle, through to the Soil CRC grower group participants at Burdekin Productivity Services and Herbert Cane Productivity Services, and the staff at the Soil CRC who supported me during my PhD and beyond.”

So, what’s next for Reuben?

“I would like to be involved in commercialising and delivering the final product for mass consumption by farming communities. Lowest cost in mass production is imperative to enable a low-cost product that is both attractive and accessible to end-users,” he said.

In keeping with his desire for continuous improvement, Reuben said he would also like to bring the device to the next level by developing an all-encompassing microfluidic device for soil fertility, soil quality and soil conditions. And perhaps, combine it with both artificial intelligence and drone technology for remote areas and large farmlands.

We’ll be following Reuben’s next venture with interest.

Watch Reuben’s 2023 research spotlight