Lead (Pb2+) toxification is a concerning, unaddressed global public health crisis that leads to 1 million deaths annually. Yet, public policies to address this issue have fallen short. This work harnesses the unique abilities of crown ethers, which selectively bind to specific ions. This study demonstrates the synergistic integration of highly-scalable silicon photonics, with crown ether amine conjugation via Fischer esterification in an environmentally-friendly fashion. This realizes an integrated photonic platform that enables the in-operando, highly-selective and quantitative detection of various ions. The development dispels the existing notion that Fischer esterification is restricted to organic compounds, facilitating the subsequent amine conjugation for various crown ethers. The presented platform is specifically engineered for selective Pb2+ detection, demonstrating a large dynamic detection range, and applicability to field samples. The compatibility of this platform with cost-effective manufacturing indicates the potential for pervasive implementation of the integrated photonic sensor technology to safeguard against societal Pb2+ poisoning.
Medicinal plants are an important source of bioactive compounds that have various biological effects on pests and diseases of agricultural and livestock importance. The present study evaluated the nematicidal and insecticidal effects of the acetone extract (E-Ac) of Prosopis laevigata leaves. The tests were carried out under in vitro conditions. E-Ac had 100% nematicidal activity against Haemonchus contortus at 40 and 20 mg/mL, while at 10 mg/mL it had nearly 60% mortality against L3 H. contortus larvae. When E-Ac was incorporated into an artificial diet, it had an 88% insecticidal effect against Melanaphis sorghi at 72 h at 10 mg/mL. The phytochemical profile of E-Ac revealed the presence of alkaloids, flavonoids, coumarins, tannins, sterols/terpenes and saponins. The results of the present study reveal that E-Ac has secondary metabolites with anthelmintic activity against L3 larvae of H. contortus and insecticidal activity against adults of M. sorghi, which could represent a viable and affordable allelopathic tool in the control of gastrointestinal nematodiasis in small ruminants and against aphids of agricultural importance.