Current Conjugation Methods for Immunosensors

Abstract

Recent advances in the development of immunosensors using polymeric nanomaterials and nanoparticles have enabled a wide range of new functions and applications in diagnostic and prognostic research. One fundamental challenge that all immunosensors must overcome is to provide the specificity of target molecular recognition by immobilizing antibodies, antibody fragments, and/or other peptides or oligonucleotide molecules that are capable of antigen recognition on a compact device surface. This review presents progress in the application of immobilization strategies including the classical adsorption process, affinity attachment, random cross-linking and specific covalent linking. The choice of immobilization methods and its impact on biosensor performance in terms of capture molecule loading, orientation, stability and capture efficiency are also discussed in this review.

A Colorimetric Enzyme-Linked Immunosorbent Assay with CuO Nanoparticles as Signal Labels Based on the Growth of Gold Nanoparticles In Situ

“…Biosensors have been developed for detection of various analytes in the fields of clinical diagnostics, food industry, pharmaceutical chemistry, and environmental science. As to the recognition elements, antibodies are the most commonly used biorecognition molecules in construction of biosensors although many efforts have being made to replace antibodies with alternative recognition molecules [1,2,3]. Thus, immunoassays are still the most widespread analytical methods for the selective and sensitive detection of targets.…”

Comparative Assessment of Affinity-Based Techniques for Oriented Antibody Immobilization towards Immunosensor Performance Optimization

“…Noncovalent physisorption or chemisorption, for example, are attractive in their simplicity but result in random antibody arrangements on the surfaces and hence in low sensor performance, leaking, and instability issues [14]. This is due to the fact that the immobilization of the asymmetric antibody molecules may take place through the variable antigen-binding sites (Fab), which leads to decreased or entirely eliminated binding activity [15]. Improvements on the stability and density of the immobilized antibodies can be achieved with the use of covalent immobilization techniques, though these methods too are far from ideal since they are often not site-directed [13,16,17], with some notable exceptions.…”

“…In the first case, reduction of the disulfide bridges to generate thiol groups in the formed antibody fragments or the use of strong oxidizing agents to generate activated diols that disrupt the conformation of the antibody and excessive loss of reactivity has been observed [13,16]. In the second case, the increased number of processing and purification steps required result in antibody losses [15].…”

The diagnostic potential of microneedles in infectious diseases

“…Therefore, the microneedle fabrication technique should ideally promote high-density probe immobilisation and optimal probe orientation and minimise non-specific binding while ensuring that the microneedle surface is biocompatible. Various immobilisation strategies are available, and their success will depend largely on the properties of the initial deposition surface [67], [69]. Furthermore, increasing the number of microneedles per array will increase the surface area for probe deposition, thus increasing device sensitivity and its multiplexing potential.…”