An ultrasensitive assay for the detection of Pb(II) has been developed using whispering gallery mode (WGM) sensing. In this technique a photonic microcavity was decorated with glutathione (GSH)-modified gold nanoparticles (Au NPs). The resonator was functionalized using an aminosilane to promote adhesion of the GSH-modified NPs creating a highly sensitive sensor specific to Pb(II). Upon introduction of Pb(II) solutions via a fluidic cell, Pb(II) ions bind to the GSH-Au NP complex and induce a shift of the resonant wavelength. Using this detection strategy we show that we are able to detect Pb(II) concentrations down to 0.05 nM in the presence of alkaline and heavy metal interferences such as Mg(II), Mn(II), Ca(II), Ni(II), Cd(II), Cr(II), Fe(II), and Hg(II). The signal was found to be proportional to the Pb(II) concentration within the range of 2.40-48.26 nM and was found to have an association constant of 2.15 × 10(5) M(-1) s(-1). The sensitivity obtained shows unparalleled advantages over currently available technology and satisfies the exposure thresholds set out by world organizations such as International Agency for Research on Cancer (IARC) and the Environmental Protection Agency (EPA). We believe that this sensor has the potential to be made portable for applications in environmental monitoring and in-field applications.

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The therapeutic potential of small molecules targeting G-quadruplexes has gained credibility since such structures were shown to form in human cells and to be highly prevalent in the human genome, most notably at telomere ends and in oncogene promoters. Herein, we perform whispering gallery mode (WGM) sensing for monitoring DNA–small molecule interactions. Unlike most existing technologies, WGM sensing offers numerous advantages including high sensitivity, real-time analysis, easy access to kinetic parameters, and much lower cost than current gold standards. In this work, interactions of five known DNA-binding ligands with either G-quadruplex or duplex DNA immobilized on a sphere microresonator have been assessed. The induced shift of the resonant mode from quadruplex (or duplex)–ligand binding was used to estimate kinetic parameters. Association and dissociation rate constants (kon and koff, respectively) as well as dissociation equilibrium constants (KD) were measured for these five ligands binding to both duplex and quadruplex DNA

A simple flow injection analysis (FIA) integrating with a metal-free approach for total antioxidant capacity (TAC) was developed. The non-toxic reaction was based on generating a vibrant blue radical from imipramine to avoid the potential interferents arising from the colorful fruit extracts. The blue radical can be rapidly scavenged by antioxidant compounds present in the sample. TAC values of Thai tropical fruit extracts were assessed by monitoring the quenching in absorbance of the test mixture following the addition of the antioxidant compounds/fruit extracts. The FIA cooperated in order to increase the sample throughput. The results demonstrated that Antidesma thwaiteaianum Muell. Arg. has the highest capacity followed by Terminalia chebula Retz. and Phyllanthus Emblica Linn., respectively. An excellent correlation between the proposed method was found with the DPPH assay. The proposed method allowed the TAC determination of fruit extracts in a high-throughput and straightforward way in accordance with the principles of green analytical chemistry.

Fruits and vegetables pack with various antioxidant compounds which are known as an essential constituent for maintaining health. Unfortunately, the shelf life of fresh produces is short after harvesting. As a result, a dehydration process by converting freshly harvested parts into powders can be an alternative to extend the storage period. The powder delivers not only nutrients, flavor, color, and texture, but the dehydrated form is also easy for storage, transportation, and is used as an ingredient in healthy products. However, the loss of essential nutrients can besides occur during the dehydration process. In order to develop superfoods, choosing the type of fruits and vegetables which can maintain the highest both favor and nutritional is the most crucial consideration to gain the highest phytonutrients after the preservative process. This study was designed to explore and evaluate the potential of tropical Thai’s fruit and vegetable powders on antioxidant activity based on total phenolic compound (TPC) compared with the commercial superfoods outside the country. The TPC was assessed based on the Folin–Ciocalteu reagent (FCR), correlating with antioxidant capacities. Gallic acid equivalents (GAE) in milligrams per gram dry of the sample was expressed. The highest GAE of the imported product (from a total of nine samples) was found to be 11.32+0.09 mg whereas the highest level of the total polyphenols was found in Thai’s veggies (Teaw) and fruit (Emblica) at 152.16+11.10 and 134.82+2.27, respectively. These GAE values are higher than the GAE values of selected imported fruits and veggies, which are well known as superfood constituents.