affinity biosensors are, without any doubt, among the most sensitive analytical devices available, offering low limits of detection and wide linear response ranges. There are, however, only a few papers detailing the application of impedimetric biosensors for the analysis of clinically relevant samples with due clinical performance. The fact that these devices have not found their way to any commercial or clinical use to date might be surprising, since an electrochemical assay platform based on portable potentiostats is a success story for monitoring a range of clinical parameters such as ions, haematological indicators and glucose. This review discusses the reasons behind this discrepancy and addresses the barriers to be overcome in order to achieve the point-of-care diagnostics using such devices for detection of protein oncomarkers approved by FDA. The final part of the review covers the most recent progress in the area.[a] Dr.
Impedimetric lectin biosensors capable
of recognizing two different
carbohydrates (galactose and sialic acid) in glycans attached to antibodies
isolated from human serum were prepared. The first step entailed the
modification of a gold surface by a self-assembled monolayer (SAM)
deposited from a solution containing a carboxybetaine-terminated thiol
applied to the subsequent covalent immobilization of lectins and to
resist nonspecific protein adsorption. In the next step, Sambucus nigra agglutinin (SNA) or Ricinus communis agglutinin (RCA) was covalently
attached to the SAM, and the whole process of building a bioreceptive
layer was optimized and characterized using a diverse range of techniques
including electrochemical impedance spectroscopy, cyclic voltammetry,
quartz crystal microbalance, contact angle measurements, zeta-potential
assays, X-ray photoelectron spectroscopy, and atomic force microscopy.
In addition, the application of the SNA-based lectin biosensor in
the glycoprofiling of antibodies isolated from the human sera of healthy
individuals and of patients suffering from rheumatoid arthritis (RA)
was successfully validated using an SNA-based lectin microarray. The
results showed that the SNA lectin, in particular, is capable of discriminating
between the antibodies isolated from healthy individuals and those
from RA patients based on changes in the amount of sialic acid present
in the antibodies. In addition, the results obtained by the application
of RCA and SNA biosensors indicate that the abundance of galactose
and sialic acid in antibodies isolated from healthy individuals is
age-related.
The initial part of this review details the controversy behind the use of a serological level of prostate-specific antigen (PSA) for the diagnostics of prostate cancer (PCa). Novel biomarkers are in demand for PCa diagnostics, outperforming traditional PSA tests. The review provides a detailed and comprehensive summary that PSA glycoprofiling can effectively solve this problem, thereby considerably reducing the number of unnecessary biopsies. In addition, PSA glycoprofiling can serve as a prognostic PCa biomarker to identify PCa patients with an aggressive form of PCa, avoiding unnecessary further treatments which are significantly life altering (incontinence or impotence).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.