Simple yet ultrasensitive and accurate quantification of a variety of analytical targets by virtue of a universal sensing device holds promise to revolutionize environmental monitoring, medical diagnostics, and food safety. Here, we propose a novel optical surface plasmon resonance (SPR) system in which the frequency-shifted light of different polarizations returned the laser cavity to stimulate laser heterodyne feedback interferometry (LHFI), hence amplifying the reflectivity change caused by the refractive index (RI) variations on the gold-coated SPR chip surface. In addition, the s-polarized light was further used as the reference to compensate the noise of the LHFI-amplified SPR system, resulting in nearly 3 orders of magnitude enhancement of RI resolution (5.9 × 10–8 RIU) over the original SPR system (2.0 × 10–5 RIU). By exploiting nucleic acids, antibodies, and receptors as recognition materials, a variety of micropollutants were detected with ultralow detection limits, ranging from a toxic metal ion (Hg2+, 70 ng/L) to a group of commonly occurring biotoxin (microcystins, 3.9 ng microcystin-LR/L) and a class of environmental endocrine disruptors (estrogens, 0.7 ng 17β-estradiol/L). This sensing platform exhibits several distinct characteristics, including dual improvement of sensitivity and stability and common-path optical construction without needing optical alignment, demonstrating a promising avenue toward environmental monitoring.
Bibliographical noteFunding Information:
We acknowledge support from the Newton Advanced Fellowship of Royal Society under Grant 191072, the National Key Research and Development Project under Grant 2022YFF0609100, and the National Natural Science Foundation of China under Grants 21976100 and 51961130387.
This is an author accepted manuscript, please find version of record here: https://doi.org/10.1021/acs.est.3c01328
- Environmental monitoring
- Laser heterodyne feedback
- Polarized light compensation
- Surface plasmon resonance
- Ultrasensitive detection