A graphene-based glycan biosensor for electrochemical label-free detection of a tumor-associated antibody

The study describes development of a glycan biosensor for detection of a tumor-associated antibody. The glycan biosensor is built on an electrochemically activated/oxidized graphene screen-printed electrode (GSPE). Oxygen functionalities were subsequently applied for covalent immobilization of human serum albumin (HSA) as a natural nanoscaffold for covalent immobilization of Thomsen-nouvelle (Tn) antigen (GalNAc-O-Ser/Thr) to be fully available for affinity interaction with its analyte—a tumor-associated antibody. The step by step building process of glycan biosensor development was comprehensively characterized using a battery of techniques (scanning electron microscopy, atomic force microscopy, contact angle measurements, secondary ion mass spectrometry, surface plasmon resonance, Raman and energy-dispersive X-ray spectroscopy). Results suggest that electrochemical oxidation of graphene SPE preferentially oxidizes only the surface of graphene flakes within the graphene SPE. Optimization studies revealed the following optimal parameters: activation potential of +1.5 V vs. Ag/AgCl/3 M KCl, activation time of 60 s and concentration of HSA of 0.1 g L−1. Finally, the glycan biosensor was built up able to selectively and sensitively detect its analyte down to low aM concentration. The binding preference of the glycan biosensor was in an agreement with independent surface plasmon resonance analysis.The financial support received from the Slovak Scientific Grant Agency VEGA 2/0137/18 and 2/0090/16 from the Slovak Research and Development Agency APVV 17-0300 is acknowledged. This publication is the result of the project implementation: Centre for materials, layers and systems for applications and chemical processes under extreme conditions—Stage I, ITMS no.: 26240120007, supported by the ERDF. This publication was supported by Qatar University Collaborative Grant QUCG-CAM-19/20-2. The findings achieved herein are solely the responsibility of the authors.Scopu

Antibodies against aberrant glycans as cancer biomarkers

Introduction: The review provides a comprehensive overview about applicability of serological detection of autoantibodies against aberrant glycans as cancer biomarkers. Areas covered: Clinical usefulness of autoantibodies as cancer biomarkers is discussed for seven types of cancers with sensitivity and specificity of such biomarkers provided. Moreover, an option of using serological antibodies against a non-natural form of sialic acid�N-glycolylneuraminic acid (Neu5Gc), which is taken into our bodies together with red meat, as a potential cancer biomarker is discussed shortly as well. Expert opinion: In the final part of the review, we discuss what measures need to be applied for selective implementation of autoantibody assays into a clinical practice. Moreover, we discuss key challenges ahead for reliable and robust detection of autoantibodies against aberrant glycans as biomarkers for disease diagnostics and for stratification of cancer patients. - 2019, - 2019 Informa UK Limited, trading as Taylor & Francis Group.The authors would like to acknowledge the financial support received from the Slovak Research and Development Agency APVV 17-0300. This work was supported by Ministry of Health of the Slovak Republic under the project registration number 2018/23-SAV-1. P. K. thanks that this work was also made possible by Qatar University grant QUCG-CAM-19/20-2. The finding achieved herein is solely the responsibility of the authors.Scopu

Electrochemical surface activation of commercial tungsten carbide for enhanced electrocatalytic hydrogen evolution and methanol oxidation reactions

The chemistry of electrocatalysts deals with multiple critical factors to facilitate the electrochemical reactions. Among those, the rate limiting depends on electrons transfer for chemisorptions of molecules in redox reactions. This feature can be directly linked with efficient catalyst support material in electrocatalysis. To this end, we have developed a novel, simple and facile route to introduce commercially available material with tuned surface and interface chemistry for their potential applications in fuel cells (FCs) science and technology. Commercial tungsten carbide (WC) was activated by means of electrochemical oxygen reduction reactions (ORR) on different rotation rates to induce mild interactions of oxygen molecules with surface of WC at specified reduction potentials. The X-ray diffraction and X-ray photoelectron spectroscopy analysis before and after the activation confirmed the tuning of WC surface with incorporation of potential factors to activate them for enhanced electrocatalytic activities. In addition, the electrocatalytic methanol oxidation reactions (MOR) and hydrogen evolution reactions (HER) were carried and confirmed the exceptional boosted-up electrocatalytic behaviour of WC after the activation. The enhancement in electrocatalytic mechanism after activation was also tested and proved by means of in-situ FTIR spectroelectrochemical analysis for methanol electro-oxidation. In addition, the electrochemical depositions of Pt nanoparticles were carried out on WC surface before and after the activation to reveal the influence of surface activation for accommodating the foreign particles as support material in electrocatalysis. The results shown two fold enhancement in anodic performance of Pt-modified activated WC catalyst for methanol oxidation reactions and hydrogen evolution reactions in fuel cells. 2022This work was made possible by project NPRP grant # 9 -219-2-105 from the Qatar National Research Fund (A Member of The Qatar Foundation). This publication was supported by Qatar University Grant QUCG-CAM-22/23-504. The finding achieved herein is solely the responsibility of the authors. Authors thank to Center for Advanced Materials, Qatar University for facilities. XPS analysis was accomplished in part in the Gas Processing Center, College of Engineering, Qatar University.Scopu