Real-Time Monitoring of Heavy Metals in Healthcare via Twistable and Washable Smartsensors

Emerging Biohybrids of Aptamer-Based Nano-Biosensing Technologies for Effective Early Cancer Detection

Cancer is a leading global cause of mortality, which underscores the imperative of early detection for improved patient outcomes. Biorecognition molecules, especially aptamers, have emerged as highly effective tools for early and accurate cancer cell identification. Aptamers, with superior versatility in synthesis and modification, offer enhanced binding specificity and stability compared with conventional antibodies. Hence, this article reviews diagnostic strategies employing aptamer-based biohybrid nano-biosensing technologies, focusing on their utility in detecting cancer biomarkers and abnormal cells. Recent developments include the synthesis of nano-aptamers using diverse nanomaterials, such as metallic nanoparticles, metal oxide nanoparticles, carbon-derived substances, and biohybrid nanostructures. The integration of these nanomaterials with aptamers significantly enhances sensitivity and specificity, promising innovative and efficient approaches for cancer diagnosis. This convergence of nanotechnology with aptamer research holds the potential to revolutionize cancer treatment through rapid, accurate, and non-invasive diagnostic methods.

Electropolymerization of poly(phenol red) on laser-induced graphene electrode enhanced adsorption of zinc for electrochemical detection

We present a highly sensitive and selective electrode of laser-induced graphene modified with poly(phenol red) (P(PhR)@LIG) for measuring zinc nutrition in rice grains using square wave anodic stripping voltammetry (SWASV). The physicochemical properties of P(PhR)@LIG were investigated with scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Fourier infrared spectroscopy (FT-IR) and Raman spectroscopy. The modified electrode demonstrated an amplified anodic stripping response of Zn2+ due to the electropolymerization of P(PhR), which enhanced analyte adsorption during the accumulation step of SWASV. Under optimized parameters, the developed sensor provided a linear range from 30 to 3000 μg L-1 with a detection limit of 14.5 μg L-1. The proposed electrode demonstrated good reproducibility and good anti-interference properties. The sensor detected zinc nutrition in rice grain samples with good accuracy and the results were consistent with the standard ICP-OES method.

Electrochemical sensing fibers for wearable health monitoring devices

Real-time monitoring of health conditions is an emerging strong issue in health care, internet information, and other strongly evolving areas. Wearable electronics are versatile platforms for non-invasive sensing. Among a variety of wearable device principles, fiber electronics represent cutting-edge development of flexible electronics. Enabled by electrochemical sensing, fiber electronics have found a wide range of applications, providing new opportunities for real-time monitoring of health conditions by daily wearing, and electrochemical fiber sensors as explored in the present report are a promising emerging field. In consideration of the key challenges and corresponding solutions for electrochemical sensing fibers, we offer here a timely and comprehensive review. We discuss the principles and advantages of electrochemical sensing fibers and fabrics. Our review also highlights the importance of electrochemical sensing fibers in the fabrication of "smart" fabric designs, focusing on strategies to address key issues in fiber-based electrochemical sensors, and we provide an overview of smart clothing systems and their cutting-edge applications in therapeutic care. Our report offers a comprehensive overview of current developments in electrochemical sensing fibers to researchers in the fields of wearables, flexible electronics, and electrochemical sensing, stimulating forthcoming development of next-generation "smart" fabrics-based electrochemical sensing.

The development of wearable technologies and their potential for measuring nutrient intake: Towards precision nutrition

Appropriate food intake and nutritional status are crucial for the maintenance of health and disease prevention. Conventional dietary assessment is mainly based on comparisons of nutrient intakes with reference intakes, failing to meet the needs of personalised nutritional guidance based on individual nutritional status. Given their capability of providing insights into health information non-invasively in real time, wearable technologies offer great opportunities for nutrition monitoring. Nutrient metabolic profiles can be monitored immediately and continuously which could potentially offer the possibility for the tracking and guiding of nutrient intake. Here, we review and highlight the recent advances in wearable sensors from the perspective of sensing technologies for nutrient detection in biofluids. The integration of biosensors with wearable devices serves as an ideal platform for the analysis of biofluids including sweat, saliva and tears. The wearable sensing systems applied to the analysis of typical nutrients and important metabolites are demonstrated in terms of carbohydrates, proteins, lipids, vitamins, minerals and others. Taking advantage of their high flexibility and lightweight, wearable sensors have been widely developed for the in situ quantitative detection of metabolic biomarkers. The technical principles, detection methods and applications are summarised. The challenges and future perspectives for wearable nutrition monitoring devices are discussed including the need to better determine relationships among nutrient metabolic profile, nutrient intake and food intake. With the development of materials, sensing techniques and manufacturing processes, wearable technologies are paving the way towards personalised precision nutrition, although there is still a long way to go before they can be utilised for practical clinical applications. Joint research efforts between nutrition scientists, doctors, engineers and sensor researchers are essential to further accelerate the realisation of reliable and practical wearable nutrition monitoring platforms.

Textile-based electrochemical sensors and their applications

Textile and their composite-based functional sensors are extensively acknowledged and preferred detection platforms in recent times. Developing suitable methodologies for fabricating textile sensors can be achieved either by integration of conductive fibers and yarns into textiles using technologies such as weaving, knitting and embroidery; or by functionalization of textile materials with conductive nanomaterials/inks using printing or coating methods. Textile materials are gaining enormous attention for fabricating soft lab-on-fabric devices due to their unique features such as high flexibility, wear and wash resistance, mechanical strength and promising sensing performances. Owing to these collective properties, textile-based electrochemical transducers are now showcasing rapid and accurate electrical measurements towards real time point-of-care diagnostics and environmental monitoring applications. The present review provides a brief overview of key progress made in the field of developing textile materials and their composites-based electrochemical sensors and biosensors in recent years where electrode configurations are specifically based on either natural or synthetic fabrics. Different ways to fabricate and functionalize textiles for their application in electrochemical analysis are briefly discussed. The review ends with a conclusive note focusing on the current challenges in the fabrication of textile-based stable electrochemical sensors and biosensors.

Laser-enabled flexible electrochemical sensor on finger for fast food security detection

Today's rampant abuse of antibiotics and lean meat powder disturbs environment and threatens public human health. Therefore, fast in-site detection of antibiotics or lean meat powder residue could avoid potential risks. In this work, flexible graphene electrodes (FGE) were easily and facilely patterned and prepared by CO₂ laser at room environment, which was coupled with a portable electrochemical analyzer for electronic signal transmission. Laser-enabled flexible electrochemical sensor on finger can be used for rapid real-time in-site electrochemical identification of chloramphenicol (CAP), clenbuterol (CLB) and ractopamine (RAC) in meat. The electrochemical response of CAP, CLB and RAC is investigated with the limit of detection of 2.70, 1.29 and 7.81 μM and the linear range of 10-200, 5-80 and 25-250 μM in phosphate buffer saline (PBS) pH 7.0, correspondingly. The minimum detection concentrations of CAP, CLB and RAC were 20, 10 and 30 μM, respectively, in actual samples of pork. And the minimum detection concentrations of CAP, CLB and RAC were 10, 5 and 25 μM in milk, respectively. Such an integrated sensing platform enriches application of sensors on finger in food security and provides information that prevents drug containments from entering food chain.

Non-invasive electrochemistry-driven metals tracing in human biofluids

Wearable analytical devices represent the future for fast, de-centralized, and human-centered health monitoring. Electrochemistry-based platforms have been highlighted as the role model for future developments amid diverse strategies and transduction technologies. Among the various relevant analytes to be real-time and non-invasively monitored in bodily fluids, we review the latest wearable achievements towards determining essential and toxic metals. On-skin measurements represent an excellent possibility for humankind: real-time monitoring, digital/fast communication with specialists, quick interventions, removing barriers in developing countries. In this review, we discuss the achievements over the last 5 years in non-invasive electrochemical platforms, providing a comprehensive table for quick visualizing the diverse sensing/technological advances. In the final section, challenges and future perspectives about wearables are deeply discussed.

Electrochemical detection of heavy metal ions in water

Heavy metal ions are one of the main sources of water pollution. Most heavy metal ions are carcinogens that pose a threat to both ecological balance and human health. With the increasing demand for heavy metal detection, electrochemical detection is favorable due to its high sensitivity and efficiency. Here, after discussing the pollution sources and toxicities of Hg(ii), Cd(ii), As(iii), Pb(ii), UO₂(ii), Tl(i), Cr(vi), Ag(i), and Cu(ii), we review a variety of recent electrochemical methods for detecting heavy metal ions. Compared with traditional methods, electrochemical methods are portable, fast, and cost-effective, and they can be adapted to various on-site inspection sites. Our review shows that the electrochemical detection of heavy metal ions is a very promising strategy that has attracted widespread attention and can be applied in agriculture, life science, clinical diagnosis, and analysis.

A rime ice-inspired bismuth-based flexible sensor for zinc ion detection in human perspiration

A nature-inspired special structure of bismuth is newly presented as Zn ion sensing layer for high-performance electrochemical heavy metal detection sensor applications. The rime ice-like bismuth (RIBi) has been synthesized using an easy ex situ electrodeposition method on the surface of a flexible graphene-based electrode. The flexible graphene-based electrode was fabricated via simple laser-writing and substrate-transfer techniques. The Zn ion sensing performance of the proposed heavy metal sensor was evaluated by square wave anodic stripping voltammetry after investigating the effects of several parameters, such as preconcentration potential, preconcentration time, and pH of acetate buffer. The proposed RIBi-based heavy metal sensor demonstrated a good linear relationship between concentration and current in the range 100-1600 ppb Zn ions with an acceptable sensitivity of 106 nA/ppb·cm². The result met the requirements in terms of common human perspiration levels (the average Zn ion concentration in perspiration is 800 ppb). In addition, the heavy metal sensor response to Zn ions was successfully performed in human perspiration samples as well, and the results were consistent with those measured by atomic absorption spectroscopy. Besides, the fabricated Zn ion sensor exhibited excellent selectivity, repeatability, and flexibility. Finally, a PANI-LIG-based pH sensor (measurement range: pH 4-7) was also integrated with the Zn ion sensor to form a single chip hybrid sensor. These results may provide a great possibility for the use of the proposed flexible sensor to realize wearable perspiration-based healthcare systems. Graphical abstract.

Defect-enhanced electrochemical property of h-BN for Pb2+ detection

A new strategy has been developed for the determination of trace lead ions (Pb²⁺) based on hexagonal boron nitride (h-BN) laden with point defect. The defect-laden boron nitride (D-BN) was synthesized by a thermal polymerization route, in which melamine borate was used as a precursor. The defect microstructure was confirmed by photoluminescence (PL) and x-ray diffraction (XRD) techniques. As compared with h-BN, the D-BN-modified glassy carbon electrode (GCE) showed an enhanced electrochemical response towards Pb²⁺ peaking at - 0.551 V (vs. SCE), which was evidenced by linear sweep anodic stripping voltammetry (LSASV) results. The point defect plays a pivotal role in the electrocatalytic reaction process, which can mediate the electronic structure and surface properties of h-BN. Accordingly, the sensor presented a low detection limit of 0.15 μg/L towards Pb²⁺ and a wide linear response concentration range from 0.5 to 400 μg/L (correlation coefficient = 0.995). In view of its superior selectivity, stability, and reproducibility, the proposed method was applied for Pb²⁺ determination in real samples and exhibited satisfactory results. This work provides insight for the construction of electrochemical sensor with high-performance by engineering defects of modifying materials. Defect-loaden h-BN exhibited enhanced electrocatalytic redox reaction towards lead ions and thus a novel Pb²⁺ sensor with high performances was constructed.