Universal protocol for the wafer-scale manufacturing of 2D carbon-based transducer layers for versatile biosensor applications.

In this manuscript, we present a comprehensive fabrication protocol for high-performance graphene oxide (GO) sensor concepts. It is suitable for a variety of biosensing applications and contains the essential process steps, starting with vapor phase evaporation for siloxane monolayers, followed by spin-coating of GO as a nanometer-thin transducer with exceptional homogeneity and micromechanical surface methods which enable seamless transformation of GO transducers to be desired micro and nano dimensions. In addition to linking basic research and innovative sensor concepts with an outlook for commercial applications of point-of-care systems for early-stage diagnostics, the authors consider it necessary to take a closer look at the manufacturing processes to create more transparency and clarity, to manufacture such specific sensor concepts systematically.

Full-length antibodies versus single-chain antibody fragments for a selective impedimetric lectin-based glycoprofiling of prostate specific antigen.

The main aim of the research was to design a functional impedimetric biosensor able to glycoprofile prostate specific antigen (PSA), a biomarker for prostate cancer (PCa), with high specificity using lectins as glycan recognising proteins. Traditionally, full-length antibody is immobilised on the biosensor interface for specific capture of PSA with subsequent glycoprofiling of PSA by addition of lectins. Since full-length antibodies contain glycans in the Fc domain, particular attention has to be paid to suppress direct binding of lectins to immobilised full-length antibodies, which would compromise accurate glycoprofiling.

Optimization of the Small Glycan Presentation for Binding a Tumor-Associated Antibody: Application to the Construction of an Ultrasensitive Glycan Biosensor.

The main aim of the study was to optimize the interfacial presentation of a small antigen-a Tn antigen (N-acetylgalactosamine)-for binding to its analyte anti-Tn antibody. Three different methods for the interfacial display of a small glycan are compared here, including two methods based on the immobilization of the Tn antigen on a mixed self-assembled monolayer (SAM) (2D biosensor) and the third one utilizing a layer of a human serum albumin (HSA) for the immobilization of a glycan forming a 3D interface. Results showed that the 3D interface with the immobilized Tn antigen is the most effective bioreceptive surface for binding its analyte.

Determining the binding affinities of prostate-specific antigen to lectins: SPR and microarray approaches.

Prostate cancer (PCa) is one of the most common newly diagnosed cancers among men and we focused on its traditional biomarker, prostate-specific antigen (PSA), using targeted glycomics-based strategies. The aberrant glycosylation pattern of PSA may serve as a valuable tool for improving PCa diagnosis including its early-stage. In this study, we evaluated the usability of two techniques, surface plasmon resonance and protein microarray assay, for the study and characterization of interactions of PSA (both free and complexed) with six lectins (SNA, ConA, RCA, AAL, WGA and MAA II).

Lectin-based lateral flow assay: proof-of-concept.

Lateral flow assays (LFAs) enable the simple and rapid detection and quantification of analytes and is popular for point-of-care (PoC), point-of-use and outdoor testing applications. LFAs typically depend on antibody or nucleic acid based recognition. We present the innovative concept of a LFA using lectins in the role of the biorecognition element.

Optical biosensors.

Optical biosensors represent the most common type of biosensor. Here we provide a brief classification, a description of underlying principles of operation and their bioanalytical applications. The main focus is placed on the most widely used optical biosensors which are surface plasmon resonance (SPR)-based biosensors including SPR imaging and localized SPR.

DNA aptamer-based sandwich microfluidic assays for dual quantification and multi-glycan profiling of cancer biomarkers.

Two novel sandwich-based immunoassays for prostate cancer (PCa) diagnosis are reported, in which the primary antibody for capture is replaced by a DNA aptamer. The assays, which can be performed in parallel, were developed in a microfluidic device and tested for the detection of free Prostate Specific Antigen (fPSA). A secondary antibody (Aptamer-Antibody Assay) or a lectin (Aptamer-Lectin Assay) is used to quantify, by chemiluminescence, both the amount of fPSA and its glycosylation levels.

An ultrasensitive impedimetric glycan biosensor with controlled glycan density for detection of lectins and influenza hemagglutinins.

An impedimetric glycan biosensor with optimised glycan density was applied for the detection of lectins and influenza hemagglutinins down to attomolar concentrations (aM).