Biosensors Based on Ion-Sensitive Field-Effect Transistors for HLA and MICA Antibody Detection in Kidney Transplantation

This work demonstrates the ability of the Ion-Sensitive Field-Effect Transistor (ISFET)-based immunosensor to detect antibodies against the human leukocyte antigen (HLA) and the major histocompatibility complex class-I-related chain A (MICA). The sensing membrane of the ISFET devices was modified and functionalized using an APTES-GA strategy. Surface properties, including wettability, surface thickness, and surface topology, were assessed in each module of the modification process. The optimal concentrations of HLA and MICA proteins for the immobilization were 10 and 50 μg/mL. The dose-response curve showed a detection range of 1.98–40 µg/mL for anti-HLA and 5.17–40 µg/mL for anti-MICA. The analytical precision (%CV) was found to be 10.69% and 8.92% for anti-HLA and -MICA, respectively. Moreover, the electrical signal obtained from the irrelevant antibody was considerably different from that of the specific antibodies, indicating the specific binding of the relevant antibodies without noise interference. The sensitivity and specificity in the experimental setting were established for both antibodies (anti-HLA: sensitivity = 80.00%, specificity = 86.36%; anti-MICA: sensitivity = 86.67%, specificity = 88.89%). Our data reveal the potential of applying the ISFET-based immunosensor to the detection of relevant anti-HLA and -MICA antibodies, especially in the field of kidney transplantation.     

Comparative investigation of thermoelectric power and cooling modules

Experimental Techniques -     

Discrete assembly of synthetic peptide-DNA triplex structures from polyvalent melamine-thymine bifacial recognition

We have designed a 21-residue α-peptide that simultaneously recognizes two decadeoxyoligothymidine (dT(10)) tracts to form triplexes with a peptide-DNA strand ratio of 1:2. The synthetic peptide side chain displays 10 melamine rings, which provide a bifacial thymine-recognition interface along the length of the 21-residue peptide. Recognition is selective for thymine over other nucleobases and drives the formation of ternary peptide·[dT(10)](2) complexes as well as heterodimeric peptide·[dT(10)C(10)T(10)] hairpin structures with triplex stems.     

Flow-Batch Method with a Sequential Injection System for Spectrophotometric Determination of Selenium(IV) in Selenium-Enriched Yeast Using o-Phenylenediamine

A precise, accurate, and reliable flow-batch spectrophotometric method for the determination of selenium (IV) was developed using o-phenylenediamine as a reagent with a sequential injection monosegmented flow system incorporating a simple heating unit. The reaction zones of selenium(IV) and o-phenylenediamine were mixed and heated in a chamber at 62°C for 5 minutes. The piaselanol complexes were then detected at a maximum absorption wavelength of 335 nm. In-line single standard calibration and standard addition procedures were developed employing the monosegmented flow technique. Under the optimized conditions, a linear calibration graph in a range of 0.1–4.0 mg L^?1 selenium (IV) was obtained with limits of detection and quantitation of 0.01 and 0.1 mg L^?1, respectively. Relative standard deviations were 2% [for both 0.1 and 0.5 mg L^?1 selenium (IV) (n = 11)]. A sample throughput of 2 h^?1 using four standard addition levels was achieved. The developed system was successfully applied to raw selenium-enriched yeast samples. The analyses performed by the developed method agreed well with those obtained from a standard inductively coupled plasma mass spectrometry method.     

Twisted Baskets

A preparative procedure for obtaining a pair of twisted molecular baskets, each comprising a chiral framework with either right ((P)‐ 1 _syn) or left ((M)‐ 1 _syn) sense of twist and six ester groups at the rim has been developed and optimized. The racemic (P/M)‐ 1 _syn can be obtained in three synthetic steps from accessible starting materials. The resolution of (P/M)‐ 1 _syn is accomplished by its transesterification with (1R,2S,5R)‐(?)‐menthol in the presence of a Ti^IV catalyst to give diastereomeric 8 ^P and 8 ^M . It was found that dendritic‐like cavitands 8 ^P and 8 ^M , in CD₂Cl₂, undergo self‐inclusion (¹H NMR spectroscopy) with a menthol moiety occupying the cavity of each host. Importantly, the degree of inclusion of the menthol group was (¹H NMR spectroscopy) found to be greater in the case of 8 ^P than 8 ^M . Accordingly, it is suggested that different folding characteristic of 8 ^P and 8 ^M ought to affect the physicochemical characteristics of the hosts to permit their effective separation by column chromatography. The absolute configuration of 8 ^P/ 8 ^M , encompassing right‐ and left‐handed “cups”, was determined with the exciton chirality method and also verified in silico (DFT: B3LYP/TZVP). Finally, the twisted baskets are strongly fluorescent due to three naphthalene chromophores, having a high fluorescence quantum yield within the rigid framework of 8 ^P/ 8 ^M .     

Thermal characterization of biodegradable methoxy poly(ethylene glycol)-b-poly(d,l-lactide)/methoxy poly(ethylene glycol)-b-poly(ε-caprolactone) blend nanoparticles

Biodegradable methoxy poly(ethylene glycol)-b-poly(d,l-lactide) (MPEG-b-PDLL) and methoxy poly(ethylene glycol)-b-poly(ε-caprolactone) (MPEG-b-PCL) diblock copolymers were synthesized by ring-opening polymerization of DLL and CL monomers in bulk using stannous octoate, and MPEG as the initiating system. Surfactant-free MPEG-b-PDLL/MPEG-b-PCL blend nanoparticles were prepared by the nanoprecipitation method. The influences of block length and blend ratio on morphology, average size, and thermal properties of the blend nanoparticles were determined. The blend nanoparticles were spherical in shape. The average particle sizes slightly decreased as the MPEG-b-PCL blend ratio increased. ¹H-NMR and thermogravimetry revealed the different MPEG-b-PDLL/MPEG-b-PCL blend ratios of the nanoparticles. Differential scanning calorimetry showed that the MPEG-b-PCL crystallinity steadily decreased as the MPEG-b-PDLL blend ratio increased, suggesting miscible blending between the MPEG-b-PDLL and MPEG-b-PCL in the amorphous phase of the nanoparticle matrix.     

Influence of Al2O3 and P2O5 contents in sol-gel ionomer glass system on the structure and their cement properties

Journal of Sol-Gel Science and Technology - Glass ionomer dental cement (GIC) is commonly used as a restorative material. The sol-gel synthesis of the ionomer glass is an alternative method, which...