Cannabinoid sensing in biofluids provides great insight into the effects of medicinal cannabis on the body. The prevalence of cannabis for pain management and illicit drug use necessitates knowledge translation in cannabinoids. In this Review, we provide an overview of the current detection methods of cannabinoids in bodily fluids emphasizing electrochemical sensing. First, we introduce cannabinoids and discuss the structure and metabolism of Δ9-THC and its metabolites in relation to blood, urine, saliva, sweat, and breath. Next, we briefly discuss lab based techniques for cannabinoids in biofluids. While these techniques are highly sensitive and specific, roadside safety requires a quick, portable, and cost-effective sensing method. These needs motivated a comprehensive review of advantages, disadvantages, and future directions for electrochemical sensing of cannabinoids. The literature shows the lowest limit of detection to be 3.3 pg of Δ9-THC/mL using electrochemical immunosensors, while electrodes fabricated with low cost methods such as screen-printing and carbon paste can detect as little as 25 and 1.26 ng of Δ9-THC/mL, respectively. Future research will include nanomaterial modified working electrodes, for simultaneous sensing of multiple cannabinoids. Additionally, there should be an emphasis on selectivity for cannabinoids in the presence of interfering compounds. Sensors should be fully integrated on biocompatible substrates with control electronics and intelligent components for wearable diagnostics. We hope this Review will prove to be the seminal work in the electrochemical sensing of cannabinoids.

Electrochemical sensing guidelines for glutamate in biofluids, associated with different diseases, providing knowledge translation among science, engineering, and medical professionals.

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Heavy metal pollution is a severe environmental problem affecting many water resources. The nonbiodegradable nature of the heavy metals such as lead (Pb) causes severe human health issues, so their cost-effective, sensitive and rapid detection is needed. In this work, we describe a simple, facile and low cost modifications of multiwalled carbon nanotubes (MWCNT) and β-cyclodextrin (βCD) through non-covalent/physical (Phys) and a covalent Steglich esterification (SE) approaches. The Phys modification approach resulted Pb detection with a limit-of-detection (LoD) of 0.9 ppb, while the SE approach showed an LoD of 2.3 ppb, both of which are well below the WHO Pb concentration guideline of 10 ppb. The MWCNT-βCD (Phys) based electrodes show negligible interference with other common heavy metal ions such as Cd 2+ and Zn 2+ . The MWCNT-βCD based electrodes were of low-cost owing to their simple synthesis approaches, exhibited good selectivity and reusability. The proposed MWCNT-βCD based electrodes is a promising technology in developing a highly affordable and sensitive electrochemical sensing system of Pb in drinking water.3 Accessibility to potable water is increasingly challenging in developing and in some developed countries due to contamination of their source waters with heavy metal ion and other pollutants. 1 Heavy metals such as lead (Pb) are non-biodegradable and widely distributed and its presence in drinking water causes greater risks to human health. 2 The effects of Pb include behavioral disorder and neurodevelopmental problems in children; increased blood pressure and renal dysfunction in adults;and even cancer in kidneys, lung, or brain due to its long-term presence in source and drinking water. [3][4][5][6][7] According to World Health Organization (WHO) guidelines, the maximum acceptable concentration of Pb in drinking water should be 10 µg/L or 10 ppb. 6 However, drinking water authorities such as in Canada are proposing an even stricter limit (e.g., 5 ppb) for Pb in drinking water. 6 Major challenges in implementing the stricter limit include the lack of on-site monitoring techniques, and detecting contaminant levels across distributed water sources. Therefore, a simple, low-cost and easy to use sensor for the detection of a heavy metal such as Pb is necessary to maintain water safety in resourcelimited areas.Conventional analytical techniques such as inductively coupled plasma mass spectrometry and atomic absorption spectroscopy require qualified testing laboratories and trained personnel. 8,9 Recently, electrochemical methods have made considerable progress towards simple, on-site and low-cost detection capabilities to allow adequate time for taking safety measures in case of a contamination. 10The electrochemical sensors, commonly referred to as "electrodes", are ideal candidates as they can be fabricated with low-cost to detect Pb with higher precision and accuracy. The material system of a sensing electrode is the key ingredient in maximizing overall performance of an electrochemical analysis in...

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Direct nanobonding of p-Si/n-GaAs wafers based on surface activation that uses an Argon (Ar)-fast atom beam at room temperature has been investigated. The bonding strength of the interface was 14.4 MPa at room temperature, and remained nearly constant after annealing up to 600 °C. An amorphous layer with a thickness of 11.5 nm was found across the interface without annealing. After annealing, the electrical current-voltage (I-V) characteristics were improved and the amorphous layer was diminished across the interface. The thermal stability of the interfacial properties of Si/GaAs indicates its potential use on the fabrication of multi-junction solar cells with Si substrate to lower the cost while improving the solar cells' efficiency. The thickness dependence of p-Si/n-Si interfacial I-V characteristics using COMSOL simulation indicates the decrease of breakdown voltage and current with the increase of the junction thickness.

A method for room temperature bonding of lead-free solders in different environments (vacuum, N 2 , air) was developed to avoid the problems caused by the high melting temperature of lead-free alloys. The method is called as surface activated bonding (SAB) method. In order to understand the influence of oxidation of Sn-Ag alloy on the bonding characteristics, the surface oxides were removed by argon fast atom beam (Ar-FAB) irradiation and then the growth of the oxides on the alloy surfaces in air was investigated by using X-ray photoelectron spectroscopy (XPS). The oxidation of Sn-Ag alloy appeared a logarithm law at room temperature. The information gathered in the investigation was applied to flip chip bonding, using Sn-Ag-Cu solder bumps at room temperature. The bond strength in different bonding environments was compared, and the results showed that the bond strength depended on the oxide thickness, and by controlling the oxidation process, a room temperature bonding might be possible even in non-vacuum conditions.