Microfluidic devices for molecular and cellular targets

A team at the Australian Institute of Bioengineering and Nanotechnology have discovered a new physical phenomenon that could lead to a new generation of ultra-sensitive point-of-care diagnostic devices.

Surface of a microfluidic device that enhances nano-shearing in a fluid—a phenomenon that could lead to ultra-sensitive point-of-care diagnostic devices in the future. Credit: Trau Laboratory, AIBN, The University of Queensland.
Surface of a microfluidic device that enhances nano-shearing in a fluid—a phenomenon that could lead to ultra-sensitive point-of-care diagnostic devices in the future. Credit: Trau Laboratory, AIBN, The University of Queensland.

One leading cause of death in the modern world is the development of cancer. While treatment regimens have significantly advanced quality-of-life in the past 30 years, it is now widely recognised that an effective diagnostic technology that can detect cancer early and monitor and personalise its treatment can potentially provide one of the greatest social and economic benefits to society this century. A team of researchers, led by Dr Muhammad Shiddiky and Professor Matt Trau, have discovered a new physical phenomenon referred to as nano-shearing that could lead to a new generation of ultra-sensitive point-of-care diagnostic devices.

“Fluid nano-shearing is a new capability of externally tuning and manipulating nanoscopic fluid flow around a biosensor surface that can enhance sensitivity and remove non-specific adsorption of molecules, cells, etc present in clinical samples. Therefore, this could have wide applications as an innovative approach to enhance the specific capture of rare molecules and cells in a microfluidic point-of-care diagnostic device—a very exciting prospect,” said Dr Shiddiky.

By understanding and exploiting this phenomenon in a sensor, the group plans to develop a platform technology that can detect molecular and cellular targets, such as cancer cells, in ultra-low concentrations. With support from ANFF-Q Professional Officer Dr Lien Chau, expert in the design and fabrication of these microfluidic devices, the group has worked to understand the nano-shearing phenomenon in order to develop a functioning device. Dr Shiddiky describes the project:

“To investigate the nano-shearing phenomenon the team has constructed microfluidic devices which contain an array of asymmetric electrode pairs within a long serpentine channel. They also fabricated devices embracing electrode pairs with a combination of planar and microtip spikes.”

To date this work has demonstrated two critical improvements for the capture of cellular targets:

  • Sensitivity—they have enhanced the capture efficiency of target cells by enhancing sensor–target interactions.
  • Specificity—they have tuned the fluid flow within the nanometres from the sensor surface to physically shear away unwanted species.

A new generation of ultra-sensitive point-of- care diagnostic devices could have great significance to the global community. These devices could find a broad utility in diagnostic and research settings; in particular they could be installed in every doctor’s surgery, 24 hour pharmacy, or nursing home, providing rapid diagnosis of conditions such as viral infections or cancer.