The unique Limacon-shaped disk microcavity design of the sensor allows for the detection of extremely low concentrations of human immunoglobulin G (IgG), a common antibody found in bodily fluids.

The Limacon-shaped design not only leads to a low lasing threshold but also improves directional light emission, making on-chip integration of the sensors more feasible.

This innovative sensor has the potential to enable cost-effective lab-on-a-chip devices for the early diagnosis of diseases, including cancers and Alzheimer's disease, as well as for addressing health crises like COVID-19.

This sensor design effectively addresses integration challenges faced by conventional sensors, facilitating point-of-care medical testing.

Experiments have demonstrated the sensors' impressive low lasing threshold of 3.87 µJ/mm² and a narrow lasing linewidth of approximately 30 pm, enabling detection of IgG at attogram-per-milliliter sensitivity.

Looking ahead, researchers plan to integrate these microlaser sensors into microfluidic chips to create optofluidic biochips capable of simultaneous quantitative detection of multiple disease biomarkers.

The sensors' ability to detect biomarkers at ultralow concentrations is essential for early disease identification, showcasing their potential impact on healthcare.

Researchers at The Hong Kong Polytechnic University have developed a groundbreaking 3D micro-printed microlaser sensor that enhances on-chip biosensing capabilities.

The microlaser operates by trapping light in microcavities, where changes in the laser's frequency indicate the binding of target molecules, significantly enhancing biodetection sensitivity.

Previous challenges with coupling light into the sensors have been mitigated by utilizing light emitted from the microlaser itself, which enhances signal collection efficiency.

This research is supported by the Research Grants Council of the Hong Kong SAR, China, with findings published in the journal Optics Letters.

The sensor was created using in-house 3D micro-printing technology, which provides high resolution and flexibility during production.