Taming Serum Interference: Marc Porter on Moving SERS Immunoassays Toward the Clinic

He attributed much of that performance to sample preparation, but cautioned that the technique’s extreme sensitivity is a double-edged sword. Because SERS can measure analytes at levels that were out of reach until recent decades, every factor affecting sensitivity and reproducibility is amplified, and variables his team once overlooked became significant.

That lesson came into focus in the group’s tuberculosis work. Early experiments performed well in buffer, but detection capability dropped by three to four orders of magnitude once the assay moved into human serum, which was a classic sign of matrix interference.

Returning to the literature, the researchers found that complications with certain tuberculosis markers had been noted but never thoroughly investigated. Their solution was an acid-based pretreatment that denatures serum proteins, breaking up the immune complexes that bind the target marker. Freeing the marker in this way allowed it to be detected in the immunoassay’s capture and labeling steps.

Porter said this approach has been central to the group’s current capabilities, and the team is now working with a company in England to commercialize the test. He urged listeners to stay tuned.

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