Sub-monolayer Biolasers: Lower Gain, Higher Sensitivity

TL;DR

This paper introduces sub-monolayer biolasers using optical fibers as microcavities, achieving ultrasensitive, disposable biomarker detection with significant sensitivity improvements over traditional monolayer biolasers.

Contribution

The study demonstrates the design of sub-monolayer biolasers with enhanced sensitivity and repeatability for biosensing, enabling ultrasensitive detection of disease biomarkers.

Findings

Achieved six orders of magnitude sensitivity enhancement over monolayer biolasers.

Demonstrated detection of Parkinson's disease biomarker alpha-synuclein at 0.32 pM in serum.

Established a general, low-cost method for ultrasensitive disposable biodetection.

Abstract

Biomarker detection is the key to identifying health risks. However, designing sensitive biosensors in a single-use mode for disease diagnosis remains a major challenge. Here, we report sub-monolayer biolasers with remarkable repeatability for ultrasensitive and disposable biomarker detection. The biolaser sensors are designed by employing the telecom optical fibers as distributed optical microcavities and pushing the gain molecules down to the sub-monolayer level. We observe a status transition from the monolayer biolaser to the sub-monolayer biolaser by tuning the specific conjugation. By reducing the fluorophores down to the threshold density (~ 3.2 x 10-13 mol/cm2), we demonstrate an ultimate sensitivity of sub-monolayer biolaser with six orders of magnitude enhancement compared with the monolayer biolasers. We further achieved ultrasensitive immunoassay for Parkinson's disease biomarker, alpha-synuclein, with a lower limit of detection of 0.32 pM in serum. This biosensor with massive fabrication capability at ultralow cost provides a general method for the ultrasensitive disposable biodetection of disease biomarkers.