Small sensors, big effects
Liquid biopsy biosensing for cancer therapies
Kevin’s Ph.D. research was acknowledged through competitive awards such as a Metrohm Australia-New Zealand Young Chemist of the Year Award in recognition of his work in developing nanotechnology-based cancer diagnostics. “This award has provided beneficial exposure to my research work and helped in fostering collaborative ties to different industry organizations,” he says.
Nanodiagnostics is the term used for the application of nanotechnology in molecular diagnosis, which is important for developing personalized cancer therapy2. Specially designed nanoparticles deliver medicines like chemotherapy straight to the tumor. The treatment isn't released until it reaches the tumor, thereby preventing the drugs from damaging healthy tissues around the tumor
A needle in a haystack problem
As we know, better disease treatment outcome is strongly tied to the performance of the molecular assays informing of treatment options. Kevin is dedicated to improving the biosensing performance of circulating nucleic acid detection for liquid biopsies. A major issue with liquid biopsy biosensing is the need to pick up a small cancer mutation signal from a lot of background noise of normal sequences, he says. The objective is to suppress this background noise effectively and leave the mutated targets for detection using highly sensitive readout nanotechnologies. And this is where the LNA (locked nucleic acid) comes in handy, Kevin recalls. He first learned about the LNA technology while conducting a literature review for annealing temperature manipulation to enable highly-specific miRNA detection. And one thing led to another. He got the idea of harnessing LNA to generate “locker probes” that specifically recognize and suppress the large excess background sequences.
Soon he was in contact with QIAGEN and had access to the resources to design several LNA-enhanced locker probes for gene fusion mutations prevalent in prostate cancer. These locker probes have since been progressively tested in cell line models3 and patient liquid biopsy samples for effective noise suppression4.
Initial findings and the future
Using LNA-modified bases to control molecular sequence hybridization of multiple targets instead of thermal cycling, Kevin and his coworkers achieved ultraselective multiplexed detection of cancer gene fusion nucleic acid (NA) variants. They recently introduced a novel nanosensor using locker probe enrichment and magneto-bioelectrocatalytic cycling to detect multiple gene fusion mutant variants in real patient liquid biopsies. This approach overcomes the challenge of detecting trace biotarget copies in the high non-target backgrounds of highly similar native and variant NA sequences.
Having shown the potential of LNA-enhanced locker probes for gene fusion mutant variant detection in patient liquid biopsies using different readouts, Kevin hopes to continuously improve and evaluate the performance of locker probes as a valuable part of a standard workflow for circulating nucleic acid analysis. “We also anticipate the expansion of similar locker probe applications for other forms of cancer mutations such as single nucleotide variants, he adds.”
While LNA technology is widely shown to be successful in recognizing and detecting target sequences, it can also be useful for successfully blocking non-target sequences during liquid biopsy analysis in the way Kevin’s work has reported. “I believe this opens a fresh perspective on harnessing LNAs' strong sequence discrimination ability in the nucleic acid biosensing community,” says Kevin.
When asked about his continued interest in driving this field forward, Kevin excitedly notes, "the tricky nature of the obstacles in enabling liquid biopsy analysis for widespread patient benefit is motivating and contributing to a crucial part of the potential solution is rewarding."