Use of Cysteamine and Glutaraldehyde Chemicals for Robust Functionalization of Substrates with Protein Biomarkers—An Overview on the Construction of Biosensors with Different Transductions

Abstract

Currently, several biosensors are reported to confirm the absence/presence of an abnormal level of specific human biomarkers in research laboratories. Unfortunately, public marketing and/or pharmacy accessibility are not yet possible for many bodily fluid biomarkers. The questions are numerous, starting from the preparation of the substrates, the wet/dry form of recognizing the (bio)ligands, the exposure time, and the choice of the running buffers. In this context, for the first time, the present overview summarizes the pre-functionalization of standard and nanostructured solid/flexible supports with cysteamine (Cys) and glutaraldehyde (GA) chemicals for robust protein immobilization and detection of biomarkers in body fluids (serum, saliva, and urine) using three transductions: piezoelectrical, electrochemical, and optical, respectively. Thus, the reader can easily access and compare step-by-step conjugate protocols published over the past 10 years. In conclusion, Cys/GA chemistry seems widely used for electrochemical sensing applications with different types of recorded signals, either current, potential, or impedance. On the other hand, piezoelectric detection via quartz crystal microbalance (QCM) and optical detection by surface plasmon resonance (LSPR)/surface-enhanced Raman spectroscopy (SERS) are ultrasensitive platforms and very good candidates for the miniaturization of medical devices in the near future.

A Capacitive Biosensor for the Early Detection of Pancreatic Cancer Using Carbohydrate Antigen 19-9

“…A standard immobilization protocol to immobilize antibodies to the gold surface of the IDE was adapted for this project [7]. All reagents and proteins used for immobilization and antigen testing are shown in Table 1.…”

Cysteamine Chemisorption at Mercury–Solution Interfaces in the Context of Redox and Microdissociation Equilibria

“…In technological applications, CA is chiefly utilized for the functionalization of various conductive surfaces, thus serving as a platform for the further attachment of biorecognition layers that enable the specific detection of desired analytes (reviewed in ref ). Other recent applications include, e.g., the covalent attachment of CA onto graphene oxide in the engineering of a selective and high-performance Hg­(II) adsorbent, the controlled etching and tapering of Au nanorods by CA, the use of CA as a linker for the controlled self-assembly of Au nanorods, or the introduction of Cu-CA nanoparticles as a new type of radiosensitizer …”

Toward Single Cell Tattoos: Biotransfer Printing of Lithographic Gold Nanopatterns on Live Cells

“…Glutaraldehyde contains aldehyde groups at both ends of the molecule and can bind to the amine groups in cysteamine and gelatin. 31 Of note, certain studies have reported that glutaraldehyde can undergo acetalization with the hydroxyl groups of alginate. 32 However, this cross-linking reaction occurs only under acidic conditions.…”

“…The bioconjugation process (Figure S4) involves sequential functionalization of the Au surface with cysteamine and glutaraldehyde and subsequent coating with 0.1% gelatin (Bloom 300, Type A). Glutaraldehyde contains aldehyde groups at both ends of the molecule and can bind to the amine groups in cysteamine and gelatin …”