Antibody Immobilization Techniques in Mass Sensitive Immunosensor: Enhanced Sensitivity through Limited Mass Load

Abstract

Background: Biosensors are analytical devices that include a sample-delivery approach between a biological recognition element and a transducer required to convert the physicochemical change produced from the interaction of biological molecules-receptor interaction into signal. The immunosensor is a special type of biosensors that includes an antibody as a biorecognition element to detect analyte as antigens. In mass-sensitive sensors, antigen-antibody interactions can be specified by measuring the frequency change and most commonly knowns are surface acoustic wave, bulk acoustic wave, quartz crystal microbalance and microcantilevers. Methods: Different methods for antibody immobilization including functionalization of the transducer surface with specific groups have been reported for antibody immobilization. This stage affects the limit of detection and overall performance. In this review, perspectives on immobilization strategies of mass sensitive immunosensors according to transducer types will be presented. The choice of immobilization methods and their impact on performance in terms of capture molecule loading, orientation and signal improvement is will also be discussed. Results: One of the most critical point during configuration of the biorecognition layer is to improve the sensitivity. Therefore, we initially focused on comparisons of the antibody immobilization strategies in the biorecognition layer in terms of mass load level and high sensitivity. Conclusion: The lack of significant data on the mass accumulations up to the functionalization and antibody immobilization steps, which are the basis of immusensor production, has been identified. However, mass sensitive immunosensors have the potential to become more common and effective analytical devices for many application areas.

Novel Sensitive Electrochemical Immunosensor Development for the Selective Detection of HopQ H. pylori Bacteria Biomarker

“…The S-NHS combined with -COOH activated by EDC and formed a semi-stable Sulfo-NHS ester, which had a half-life of hours in acidic mediums, that reacted with primary amines (-NH 2 ) on the antibodies, forming covalently bonded antibodies to MWCNT-COOH [78]. As per the standard protocol, a 7.5 µL of HopQ-Ab (10 µg/mL, 10 mM PBS, pH = 7.4) was deposited on the WE surface and left for conjugation for 45 min [29,57,[70][71][72]79]. The capture antibody (isoelectric point pH = 9.5) was positively charged at physiological pH = 7.4, which facilitated and enhanced the efficiency of immobilization due to attraction with the negative charge density on the MWCNTs [53,58,[80][81][82].…”

“…The electrochemical biosensor field has reached a milestone, driven by the highly enhanced sensitivity, excellent selectivity, lower detection limits, detection ranges, shelf-life, simplified sample preparation, and cost affordability [23,[25][26][27][28]. The use of nanomaterials and the scaling down of electrode geometry in biosensors prove to overcome fundamental limitations imposed by classical methods, especially in terms of sensitivity and LOD [27,29]. Therefore, the biosensor's inherent sensitivity is one of the main driving forces for biosensor development investigations [21,27,28].…”

Ultra-sensitive selective detection of HopQ protein as a biomarker for Helicobacter pylori bacteria by an electrochemical voltammetric sensor

“…The electrochemical biosensor field has reached a milestone, driven by the highly enhanced sensitivity, excellent selectivity, lower detection limits, detection ranges, shelf-life, simplified sample preparation, and cost affordability [19]- [25]. Scaling down the sensitivity and LOD has proven to beat the fundamental limitations imposed by classical methods, and therefore, the biosensor's sensitivity is expected to be the main driving force for future investigations [26]- [31].…”