From Sri Lanka to life-saving blood tests: AP da Silva’s molecular sensors

AP da Silva explains how a compact fluorescent PET sensor evolved into a global tool for rapid bedside blood analysis. From childhood in Colombo to a PhD in Belfast, his team stitched molecules together to create modular sensors that report ion levels in under a minute, transforming care in intensive care units, ambulances, and beyond. Serendipity, collaboration, and biocompatible chemistry power a story about science meeting real-world need.

Key ideas include photo-induced electron transfer, the sodium sensor concept, and the Roche partnership that scaled the device for worldwide use, with potential applications in cancer surgery and molecular computing.

Introduction and early life

AP da Silva, born in Colombo in 1952, faced poverty but found science through a remarkable teacher and a crucial encyclopedia bought during a flood sale. The Life Scientific interview highlights how serendipity and kindness shaped his path from Sri Lanka to Queens University Belfast, where he would later build his career in photochemistry and sensors.

"Serendip is an old name for Sri Lanka, which translates as golden island in the Indian epics." - AP da Silva

Molecular sensors and PET engineering

Da Silva describes the idea of taking molecules and stitching them together to produce emergent properties, akin to engineers combining parts to yield more than the sum of their parts. He explains the PET mechanism at the heart of fluorescent sensors: a fluorescent dye linked to a receptor undergoes photoinduced electron transfer, altering light emission depending on the local chemical environment. By selecting dyes and receptors, researchers can tailor sensors to detect specific ions with high sensitivity in tiny volumes, enabling biocompatible, in vivo diagnostics.

"We take molecules and stitch molecules together to give something super compared to what you had before." - AP da Silva

The sodium sensor concept and grandmother's treatment

The narrative pivots on a grandmother with congestive symptoms and a doctor’s insight into sodium balance. The conversation links a clinical need to a molecular solution: a sensor that can report sodium levels noninvasively or with a small blood sample. The sodium-ion coordination disrupts electron transfer, allowing the dye to emit light when sodium is present, turning a chemical signal into a measurable optical readout.

"that sodium fellow is an atom, but it can make my grandmother better again." - AP da Silva

From idea to global device with Roche

After returning to Belfast, a major collaboration with Roche transformed the concept into a portable, multi-analyte sensor platform. A microfluidic chip with six optical sensing stations can measure elements such as sodium, potassium and calcium in less than a minute, enabling rapid triage in intensive care and even in ambulances. The devices proved life-saving in critical settings and were deployed globally, including in challenging environments like the Sri Lankan civil war context.

"we could take it out to the intensive care places first, and when those were trialed there, they were saving lives straight away." - AP da Silva

Future directions and legacy

Da Silva connects the chemistry to computing, noting that the on-off states of fluorescent sensors resemble binary logic gates. He envisions a future where carbon-based, biocompatible molecular systems operate inside the body to guide therapies, assist fluorescence-guided tumor surgery, and enable new diagnostic paradigms beyond traditional silicon-based devices. The interview closes on a note of gratitude and continuity, with his ideas living on in the researchers who have carried the baton forward.

"molecules are us." - AP da Silva