Crown ether decorated silicon photonics for safeguarding against lead poisoning

TL;DR

This paper introduces a novel silicon photonic platform integrated with crown ethers for highly selective, in-situ detection of lead ions, offering a scalable solution to address the global health crisis caused by lead poisoning.

Contribution

It demonstrates the first integration of crown ethers with silicon photonics using environmentally-friendly Fischer esterification, enabling selective lead detection over a wide concentration range.

Findings

Achieved detection range of 1 to 262,000 ppb for Pb2+

Demonstrated high selectivity against other ions

Established a scalable, environmentally-friendly fabrication process

Abstract

Lead (Pb2+) toxification in society is one of the most concerning public health crisis that remains unaddressed. The exposure to Pb2+ poisoning leads to a multitude of enduring health issues, even at the part-per-billion scale (ppb). Yet, public action dwarfs its impact. Pb2+ poisoning is estimated to account for 1 million deaths per year globally, which is in addition to its chronic impact on children. With their ring-shaped cavities, crown ethers are uniquely capable of selectively binding to specific ions. In this work, for the first time, the synergistic integration of highly-scalable silicon photonics, with crown ether amine conjugation via Fischer esterification in an environmentally-friendly fashion is demonstrated. This realises a photonic platform that enables the in-situ, highly-selective and quantitative detection of various ions. The development dispels the existing notion that Fischer esterification is restricted to organic compounds, laying the ground for subsequent amine conjugation for various crown ethers. In this work, the platform is engineered for Pb2+ detection, demonstrating a large dynamic detection range of 1 - 262000 ppb with high selectivity against a wide range of relevant ions. These results indicate the potential for the pervasive implementation of the technology to safeguard against ubiquitous lead poisoning in our society.