Paulo Augusto Raymundo Pereira

The importance of early detection of neurodegenerative disorder biomarkers has grown since these biomarkers are essential for timely diagnosis, treatment, healthcare, and wellness applications. We present a cost-effective and disposable electrochemical immunosensing strip for rapid, decentralized detection of brain-derived neurotrophic factor (BDNF)one of the major neurotrophins (NTs) associated with neurological and psychiatric disordersin human saliva. The salivary BDNF immunosensor strip is made on a screen-printed carbon electrode functionalized with carbon spherical shells (CSSs), polyethylenimine (PEI), and glutaraldehyde to enhance sensitivity. Through systematic optimization, the sensor achieved excellent analytical performance, with a wide dynamic detection range from 1.0 × 10^–20 to 1.0 × 10^–10 g mL^–1, a rapid response time of under 3 min, and an ultralow detection limit of 1.0 × 10^–20 g mL^–1 for BDNF in human saliva. The BDNF immunosensor demonstrated high selectivity, reproducibility, robustness, stability, and long-term storage capability. At a cost of less than US$ 2.19 per unit, this disposable sensor also enabled rapid BDNF detection in saliva samples collected from healthy volunteers without interference from other salivary constituents. The environmental impact was assessed using the Analytical Eco-Scale (AES), the Analytical GREEnness Metric Approach (AGREE), and the Blue Applicability Grade Index (BAGI), which evaluates the practicality (“blueness”) of the device. These assessments confirmed the sustainability of the disposable BDNF immunosensor strip. This device provides a rapid, efficient, cost-effective, and reliable method for the decentralized, noninvasive salivary analysis of BDNF, enabling broader applications in healthcare, wellness monitoring, and medical diagnostics related to the neurotrophin family of biomarkers.

Wearable sensors are emerging and innovative tools in the realm of agriculture, offering new opportunities for sustainable plant monitoring practices. This perspective explores wearable sensor technology in plant monitoring to promote environmental sustainability and enhance agricultural productivity. Wearable sensors, capable of continuously tracking plant health indicators such as salinity, diseases, metabolites, pH, ions, pathogens, pesticides, parasites, phytohormones, nutrient status, moisture levels, and pest activity, provide real-time information to make precise and timely decisions. Farmers can use the diverse collected data to enhance resource use, reducing waste and the environmental impact of agricultural practices. Here, we highlight the current advancements in wearable sensor technology and explore potential applications in diverse agricultural settings, with the challenges and opportunities to be addressed to fully implement by the farming community. We also emphasize the sustainable and biodegradable substrates/supports relying on eco-friendly polymeric materials for the fabrication of cost-effective, flexible, durable, stable, and easily deployable sensor systems, which can be extensively applied by the agrifood sector. We provide a forward-looking perspective on how wearable sensors can contribute to more sustainable and efficient plant monitoring practices in precision agriculture. Given the disruptive innovation, wearable plant sensors were highlighted as Top 10 Emerging Technologies by World Economic Forum in 2023.

The selective, rapid detection of low levels of hormones in drinking water and foodstuffs requires materials suitable for inexpensive sensing platforms. We report on core-shell Ag@C nanocables (NCs) decorated with carbon spherical shells (CSSs) and silver nanoparticles (AgNPs) by using a hydrothermal green approach. Sensors were fabricated with homogeneous, porous films on screen-printed electrodes, which comprised a 115 nm silver core covered by a 122 nm thick carbon layer and CSSs with 168 nm in diameter. NCs and CSSs were also decorated with 10-25 nm AgNPs. The NC/CSS/AgNP sensor was used to detect ethinylestradiol using square wave voltammetry in 0.1 M phosphate buffer (pH 7.0) over the 1.0-10.0 μM linear range with a detection limit of 0.76 μM. The sensor was then applied to detect ethinylestradiol in tap water samples and a contraceptive pill with recovery percentages between 93 and 101%. The high performance in terms of sensitivity and selectivity for hormones is attributed to the synergy between the carbon nanomaterials and AgNPs, which not only increased the sensor surface area and provided sites for electron exchange but also imparted an increased surface area.

Since the creation of the glucose enzyme sensor in the early 1960s by Clark and Lyons