Plant wearable sensors have potential to provide continuous measurements of plant physiological information. However, stable and high-fidelity monitoring of plants with glandular hairs and wax is challenging, due to lacking interface adaptability of conventional plant wearable sensors. Here, inspired by adaptive winding plant tendrils, an integrated plant wearable system (IPWS) based on adaptive winding strain (AWS) sensor for plant pulse monitoring was developed. The IPWS consists of three modules, i.e. an AWS sensor, a flexible printed circuit, and a smart phone APP display interface. As the key element, the AWS sensor can adaptively wrap around the tomato stem. Importantly, with the serpentine-patterned laser-induced graphene, the AWS sensor exhibits excellent resistance to temperature interference with a temperature resistance coefficient of 0.17/°C. The IPWS is demonstrated to be stable and high-fidelity monitoring the plant pulse, which can reflect the growth and water state of tomato plant in real time.
In this work, blue carbon dots (Stalk-Trp CDs) with high fluorescence quantum yield were successfully prepared from biological waste cherry tomato stalk and tryptophan. The morphology, composition, and properties of Stalk-Trp CDs were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, infrared spectroscopy, ultraviolet–visible absorption spectroscopy, and fluorescence spectroscopy. On this basis, a dual-channel ratio sensing platform (Stalk-Trp CDs@Eu) was constructed using the interaction of Stalk-Trp CDs with Eu 3+ , which reduced the detection limit of the antibiotic oxytetracycline from 0.15 µmol/L to 0.018 µmol/L. Channel 1 of the dual-channel ratio sensing platform is a neutral environment (pH = 6.5), and the specific response of the probe to OTC causes its fluorescence to change from blue to purple. Channel 2 is an alkaline environment (pH = 11.5), and the fluorescence of the probe turns green only in the presence of OTC. The interaction mechanism of the dual-channel ratio sensing platform with the antibiotics oxytetracycline (OTC), chlortetracycline (CTC), and tetracycline (TC) was also revealed. The detection results of OTC in honey and milk by using Stalk-Trp CDs@Eu were highly consistent with the HPLC method recommended by the national standard. This shows that the dual-channel ratio sensing platform has great practical application value in the field of antibiotic detection.