This increased sensitivity and specificity offered by PEGylated antibodies plays a critical role in early disease detection, leading to timely treatment and better patient outcomes. Furthermore, PEGylated antibodies have found utility in the detection of bacterial infections. strategy of site-directed antibody conjugation can be engineered for coupling other protein- and non-protein-based biological molecules commonly used in POC testing and development, thus enhancing the potential for improved diagnostic accuracy and performance. Keywords: biological molecules, antibody, directional, site-specific, controlled, conjugation, immunoassay, screen-printed electrodes, point of care 1. Introduction The demand for point-of-care (POC) medicine is rapidly increasing in our modernized and globalized world. POC diagnostics have revolutionized healthcare by providing rapid and accurate disease diagnosis at the patients bedside or in a clinical setting [1]. Immunoassays are widely used in POC diagnostics for detecting analytes such as proteins, nucleic acids, and small molecules [2]. However, the sensitivity and specificity of immunoassays are limited by the availability and orientation of the antibodies on the surface of the assay platform [3]. Conventional conjugation methods involve random and non-specific chemical reactions between the antibody and the conjugation partner, such as N-hydroxysuccinimide (NHS) ester or maleimide chemistry, which can result in low yields, heterogeneous products, and reduced antibody activity [4,5]. Site-specific modification strategies have been developed to overcome limitations by enabling the selective conjugation of antibodies to specific sites and improving the availability Cangrelor Tetrasodium and orientation of the antibodies on the surface of the assay platform [6,7,8,9,10,11,12,13]. Chemical conjugation using functional polymers such as polyethylene glycol (PEG) has emerged as a superior alternative to traditional conjugation methods [14]. PEG can be easily conjugated to antibodies through various chemistries and offers several advantages compared to other polymers, including high water solubility, low toxicity, and low immunogenicity [15,16,17]. Moreover, PEG conjugation can enhance the stability and shelf-life of the Cangrelor Tetrasodium antibody, increase the solubility and bioavailability of the conjugate, and reduce the clearance rate from the body [18,19,20]. These properties make PEG an ideal candidate for conjugation with antibodies in POC diagnostics. Point-of-care diagnostics have been a game-changer in infectious disease control, providing rapid, patient-centric testing with Enpep immediate results. The importance of such rapid diagnostic tools has been highlighted in recent global health crises, such as the COVID-19 pandemic. PEGylated antibodies have been employed in lateral flow immunoassays (LFIs) for the detection of SARS-CoV-2 antigens [21]. The stability of these PEGylated antibodies allows the LFIs to deliver rapid, point-of-care diagnostics in diverse Cangrelor Tetrasodium settings, potentially contributing to widespread pandemic control. The PEGylation process has proved particularly beneficial for the detection of antigens that are usually present at low concentrations in the early stages of infection, making them challenging for traditional immunoassays to identify. PEGylated antibodies, due to their enhanced stability and activity, can bind to these low-concentration antigens and generate a stronger and more detectable signal [22]. This increased sensitivity and specificity offered by PEGylated antibodies plays a critical role in early disease detection, leading to timely treatment and better patient outcomes. Furthermore, PEGylated antibodies have found utility in the detection of bacterial infections. The use of PEGylated antibodies in LFIs has been effective in diagnosing infections caused by MRSA, Tuberculosis (TB), streptococcus pneumoniae and staphylococcus aureus [23,24,25,26]. By improving the detection limit and specificity of these immunoassays, PEGylated antibodies have bolstered the clinical utility of these diagnostic tools. PEGylation also plays a crucial role in enhancing the stability of biosensors used for infectious disease diagnosis. For instance, PEGylated antibodies have been immobilized on the surface of electrochemical biosensors, leading to a significant improvement in the detection of the hepatitis B surface agent [27]. PEGylation reduced nonspecific binding, thereby improving the biosensors sensitivity and reliability. One of the major advantages of chemical conjugation using functional polymers like PEG is that it enables site-specific modification for antibody conjugation [28,29,30]. These approaches have gained significant attention in the development of POC diagnostics. PEG enables the selective and controlled conjugation of antibodies to specific sites, reducing the risk of antibody denaturation and loss of function [31]. Moreover, PEG conjugated antibodies offer enhanced performance and accuracy in immunoassays by improving the availability and orientation of the antibodies on the assay platform. Here, we present a novel approach for PEG-mediated site-specific antibody conjugation for the Cangrelor Tetrasodium development of a POC-based electrode microchip immunoassay. We demonstrate the efficacy of our approach by developing anti-Klebsiella pneumoniae carbapenemase-2 (KPC-2) antibody-modified screen-printed gold (Au) electrodes with improved conjugation and target-capture efficiency compared to conventional conjugation Cangrelor Tetrasodium methods. In our approach, a heterobifunctional linker.