Precision phenylalanine sensing in blood with nanomaterial-enhanced electrodes.

Phenylketonuria (PKU) is a genetic disorder associated with the metabolic dysfunction of the phenylalanine hydroxylase enzyme, which catalyses the conversion of l-phenylalanine (Phe) to l-tyrosine. Elevated levels of phenylalanine disrupt the central nervous system by impairing the myelination process and leading to mental retardation. Currently, commonly used diagnostic methods for PKU include the Guthrie test, liquid chromatography, and tandem mass spectrometry, all of which necessitate sophisticated infrastructure and costly equipment. Conversely, electrochemical detection methods hold promise in clinical diagnosis due to their high accuracy, rapid response time, and user-friendly nature. The choice of electrodes in electrochemical methods significantly influences sensitivity and analytical performance. In this study, we evaluated the performance of various nanomaterial-modified electrodes and compared their responses to the redox reaction of phenylalanine, focusing on detection capabilities in blood samples. Specifically, we examined carbon nanotube-gold nanoparticle modified carbon electrode (C-CNT-GNP), graphene-gold nanoparticle modified carbon electrode (C-GPH-GNP), electrochemically reduced graphene oxide (ERGO) modified carbon electrode (C-ERGO), bare carbon electrode (C-BARE), ERGO modified gold electrode (Au-ERGO), and bare gold electrode (Au-BARE) using amperometric detection. The performance of these electrodes was compared in terms of their limit of detection (LOD), limit of quantification (LOQ), and sensitivity. Among all electrodes, ERGO gold electrode showed the lowest LOD, LOQ, and highest sensitivity. This study highlights the potential of ERGO-modified gold electrodes for enhancing electrocatalytic activity, thus offering promising prospects for further diagnostic applications.

Optimization of spray drying conditions for improved physical properties in the production of enzyme-modified cheese powder.

Enzyme-modified cheese (EMC), a cheese flavor additive with high-fat content, is preferably produced in powder form because of its long shelf-life and high industrial applicability. The physical properties of additives, especially with high-fat contents, are very important for their industrial usage, and the spray drying process conditions substantially determine the physical properties of powders. In this study, optimization of the spray drying process during the production of EMC powder was performed to improve the powder physical properties. The process factors were inlet temperature, feed flow rate, and aspiration rate, while the responses were selected as drying yield, Carr index (CI), wettability, surface fat content, and browning index (BI). The optimum spray drying conditions were calculated as 150°C, 9.1 mL/min, and 28.4 m3 /h for inlet temperature, feed flow rate, and aspiration rate, respectively. It has been determined that the spray drying conditions at low inlet temperature, medium feed flow, and aspiration rates in order to obtain improved powder physical properties should be preferred. Practical Application: Enzyme-modified cheese (EMC) is a widely used product in the development of foods with cheese flavor, and EMC in powder form offers various advantages for industrial applications such as ease in storage and transportation, long shelf-life, and product applicability, which mainly depend on powder physical properties. In powder production, spray drying is the principle process determining the powder physical properties, and optimization is essential for the desired physical properties. In this study, laboratory-scale optimization of EMC powder production was carried out, data was provided for scale-up studies, and the effects of processing conditions on powder physical properties were evaluated.

Nano-sized structures for the detection of food components and contaminants.

New methods to identify trace amount of food components and/or contaminants (infectious pathogens and chemicals) rapidly, accurately, and with high sensitivity are in constant demand to prevent foodborne illnesses. Multipurpose biofunctionalized engineered nanomaterials are very promising for the detection of food components and contaminants. The unique optical and magnetic properties of the nanoscale materials are very useful in the analysis of food. The objectives of this review paper are to discuss the development of applications of nanoscale structures related to food industries and to provide an overview of available methods of detecting food components and contaminants with particular emphasis on the use of nanoparticles.

Photoelectrochemical competitive DNA hybridization assay using semiconductor quantum dot conjugated oligonucleotides.

A competitive DNA hybridization assay based on the photoelectrochemistry of the semiconductor quantum dot-single stranded DNA conjugates (QD-ssDNA) was developed. Hybridization of QD-ssDNA with the capture probe DNA immobilized on the indium-tin oxide electrodes enables photocurrent generation when the electrochemical cell was illuminated with a light source. Upon the competition between QD-ssDNA and single-stranded target DNA, the photocurrent response decreased with the increase in the target DNA concentration. A linear relationship between the photocurrent and the target DNA concentration was obtained (R(2) = 0.991). The selectivity of system towards the target DNA was also demonstrated using non-complementary sample.