Lab-on-a-chip tech may simplify cancer detection

Scientists have developed a new lab-on-a-chip technique that may simplify the detection of cancer DNA biomarkers in blood and pave the way for new treatments for the deadly disease. Genomic biomarkers offer great potential for diagnostics and new forms of treatment, such as immunotherapy.

Miniaturised lab-on-a-chip approaches are prime candidates for developing viable diagnostic tests and instruments because they are small, need only limited test volumes and can be cost-effective. A team of scientists and engineers from the University of California, Santa Cruz and Brigham Young University in the US have developed just such an approach capable of processing biomolecular samples from blood.

Their method can analyse and identify multiple targets on a silicon-based molecular detection platform. Laboratory-on-a-chip describes the miniaturisation of laboratory functions such as blood testing on a chip. Instead of transferring relatively large (micro- to millilitres) samples between test tubes or using bulky analytical equipment, samples and reagents are handled on chip-scale devices with fluidic microchannels.

This requires much smaller test volumes, and multiple functions can be integrated on a single device, improving speed, reliability and portability of these lab processes.

"Our approach uses optofluidic chips where both fluid processing and optical sensing are done on a chip, allowing for further miniaturisation and performance enhancements of the chip system," said Holger Schmidt, professor at the University of California, Santa Cruz. Each of the chips had to be developed and tested for multiple functions, from filtering of blood cells without clogging the filter to reliably analysing optical data to create the right excitation patterns on the silicon chip. The next step to realising the potential of this research is to move towards real clinical samples and to detect individual DNA biomarkers.

"We have shown single nucleic acid analysis in the context of on-chip Ebola detection and would like to transfer that to this application," said Schmidt.

Other goals for the team include increasing the speed of the analysis process, and integrating more optical elements on the chip. They also want to expand their capabilities to analysing protein biomarkers in addition to nucleic acids and whole virus particles already demonstrated. This research is expected to have a wide range of applications because the underlying principle of this kind of on-chip optical analysis and manipulation is very general.

"In the near term, we hope to build new diagnostic instruments for molecular diagnostics with applications in oncology and infectious disease detection, both viruses and (drug-resistant) bacteria," Schmidt said.