In less than a minute, a miniature device developed at the University of Montreal can measure a patient’s blood for methotrexate, a commonly used but potentially toxic cancer drug.
According research led by Jean-François Masson and Joelle Pelletier of the university’s Department of Chemistry, the nanoscale device is just as accurate and 10 times less expensive than equipment currently used in hospitals. The device has an optical system that can rapidly gauge the optimal dose of methotrexate a patient needs, while minimizing the drug’s adverse effects.
Methotrexate has been used for many years to treat certain cancers, among other diseases, but isn’t without its problems.
“While effective, methotrexate is also highly toxic and can damage the healthy cells of patients, hence the importance of closely monitoring the drug’s concentration in the serum of treated individuals to adjust the dosage,” Masson explained.
Until now, monitoring has been done in hospitals with a device using fluorescent bioassays to measure light polarization produced by a drug sample.
“The operation of the current device is based on a cumbersome, expensive platform that requires experienced personnel because of the many samples that need to be manipulated,” Masson said.
The research started six years ago when Pelletier, a specialist of the DHFR enzyme, and Masson, an expert in biomedical instrument design, investigated how to simplify the measurement of methotrexate concentration in patients.
Here’s how it works:
Gold nanoparticles on the surface of the receptacle change the colour of the light detected by the instrument. The detected colour reflects the exact concentration of the drug in the blood sample. In the course of their research, they developed and manufactured a miniaturized device that works by surface plasmon resonance. Roughly, it measures the concentration of serum (or blood) methotrexate through gold nanoparticles on the surface of a receptacle. In “competing” with methotrexate to block the enzyme, the gold nanoparticles change the colour of the light detected by the instrument. And the colour of the light detected reflects the exact concentration of the drug in the blood sample.
“Testing was conclusive: not only were the measurements as accurate, but our device took less than 60 seconds to produce results, compared to 30 minutes for current devices,” Masson said.
“In the near future, we can foresee the device in doctors’ offices or even at the bedside, where patients would receive individualized and optimal doses while minimizing the risk of complications,” Masson added. “While traditional equipment requires an investment of around $100,000, the new mobile device would likely cost ten times less, around $10,000.”
This research received funding from the National Science and Engineering Research Council (NSERC) of Canada, the Centre for self-assembled chemical structures (CSACS), Fonds québécois de recherche – Nature et technologies (FRQ-NT) and Institut Mérieux.
Photo: University of Montreal