A Label-Free and Ultrasensitive Immunosensor for Detection of Human Chorionic Gonadotrophin Based on Graphene FETs

Abstract

We report on a label-free immunosensor based on graphene field effect transistors (G-FETs) for the ultrasensitive detection of Human Chorionic Gonadotrophin (hCG), as an indicator of pregnancy and related disorders, such as actopic pregnancy, choriocarcinoma and orchic teratoma. Pyrene based bioactive ester was non-covalently anchored onto the graphene channel in order to retain the sp2 lattice. The G-FET transfer characteristics showed repeatable and reliable responses in all surface modifying steps using a direct current (DC) readout system. The hCG concentration gradient showed a detection limit of ~1 pg·mL−1. The proposed method facilitates the cost-effective and viable production of graphene point-of-care devices for clinical diagnosis.

Manufacturing Shape-Controllable Flexible PEDOT/rGO Composite Electrodes for Planar Micro-Supercapacitors

“…Further analysis reveals that the intensity ratio of the D to G bands (ID/IG) for PEDOT/rGO is 0.97, which is higher than the 0.89 of rGO, suggesting that the presence of PEDOT nanoparticles promotes the formation of disordered multilayer graphene [40]. Additionally, a very broad 2D peak appears at 2700 cm −1 in the Raman spectra of PEDOT/rGO, reaffirming that the presence of PEDOT nanoparticles favors the production of disordered multilayer graphene [41]. The XPS technique reveals information on the chemical composition and chemical bonds of PEDOT/rGO.…”

Development of immobilized antibody-based affinity grid strategy and application in on-grid purification of target proteins for high-resolution cryo-EM

“…1A). Pyr-NHS has been used in efficient graphene-based biosensor systems [46][47][48][49][50][51] . For efficient affinity grid preparation, we opted for commercially available GO coated cryo-EM grid (abbreviated as GO grid) to assemble our IAAG grid.…”

Electrochemical Affinity Sensors Using Field Effect Transducer Devices for Chemical Analysis

“…The growth procedure will end once the substrates are fully covered with a graphene film, which is mainly referred to as the so-called "self-limiting surface reaction mechanism" that has been observed in Cu and on Ni. After one decade of research efforts, PMMA poly (methyl methacrylate)) is still the most widely used polymer to support the graphene film (one or two layers, with a minimum of cracks) during the transfer process due to its prominent features like transparency, cheapness, easy manipulation, flexibility and solubility in several organic solvents [116,125,126,128,135,136,139,140,143,145,146,150,160]. Small domains of graphene can also be obtained as reduced graphene oxide, graphene oxide being obtained from graphite by the modified Hummers' method [115,117,131,133,143,144,152,153,154,156,158].…”

“…The numerous graphene FET developed since 2015 allow the detection of biomarkers of different diseases: tuberculosis [118,162], cancer [122,133,134,140,144,153,160], trophoblastic tumors [125,126,132], mental stress [129,151,164], hyperthyroidism [135], cardiovascular disorder [139], rheumatoid arthritis [139], HIV [139], bone disease [142], Alzheimer's disease [147,161], heart failure [158]. Some of them allow the detection of virus: Hepatitis B [119,131], COVID-19 [3,149,154], japanese encephalitis [148], avian influenza [148], human papillomavirus [156], the detection of toxins: aflatoxin B1 [117], okadaic acid [130], geosmin [155], the detection of drugs [157] and the detection of a pesticide, chlorpyrifos [138].…”