A surface plasmon resonance immunosensor for human growth hormone based on fragmented antibodies

Abstract

An SPR-based immunosensor for human growth hormone (hGH) is reported. It is based on the application of fragments of antibodies against human growth hormone (anti-hGH). The native thiol groups of anti-hGH were liberated by splitting the intact anti-hGH antibody using the reducing agent 2-mercaptoethylamine (2-MEA) into two half-sized fragments (frag-anti-hGH) while retaining active antigen-binding sites. Afterwards frag-anti-hGH were immobilised on the gold film of the SPR-chip by chemisorption. The antibody and 2-MEA concentrations have been optimized with respect to the performance of the immunosensor. The surface morphology of the immunosensor was studied by atomic force microscopy. The binding of hGH to the sensor surface is highly specific, and the respective immunosensor has a limit of detection of 0.0034 μM of hGH. Good repeatability of the analytical signal and selectivity over porcine growth hormone are demonstrated. The sensor has relatively good operational stability, which was satisfactory within 18 days.