Ultrasensitive determination of human growth hormone (hGH) with a disposable electrochemical magneto-immunosensor

Abstract

In this paper, an electrochemical magneto-immunosensor for the detection of human growth hormone (hGH) is described for the first time. The immunosensor involves the use of tosyl-activated magnetic microparticles (TsMBs) to covalently immobilize a monoclonal mAbhHG antibody. A sandwich-type immunoassay with a secondary pAbhGH antibody and anti-IgG labelled with alkaline phosphatase (anti-IgG-AP) was employed. TsMBs–mAbhGH–hGH–pAbhGH–anti-IgG-AP conjugates were deposited onto the surface of a screen-printed gold electrode using a small neodymium magnet, and electrochemical detection was performed by square-wave voltammetry upon the addition of 4-aminophenyl phosphate as the AP substrate. All the variables involved in the preparation of immunoconjugates and in the immunoassay protocol were optimized. A calibration curve for hGH was constructed with a linear range between 0.01 and 100 ng/mL (r = 0.998) and a limit of detection of 0.005 ng/mL. This value is nearly three orders of magnitude lower than that obtained using surface plasmon resonance (Treviño et al., Talanta 78:1011-1016, 2009). Furthermore, good repeatability, with RSD = 3% (n = 10) at the 1-ng/mL hGH level, was obtained. Cross-reactivity studies with other hormones demonstrated good selectivity. The magneto-immunosensor was applied to the analysis of human serum spiked with hGH at the 4- and 0.1-ng/mL levels. Mean recoveries of 96 ± 6% and 99 ± 2%, respectively, were obtained.

Direct and label‐free detection of the human growth hormone in urine by an ultrasensitive bimodal waveguide biosensor

“…In addition, the extended use of hGH for sport doping makes necessary the implementation of new detection systems able to detect low quantities of hGH preferably in urine samples and in a user‐friendly way. To detect hGH in urine at clinically relevant levels, different methodologies have already been developed but normally they require fluorescent or magnetic amplification . The most sensitive method to detect hGH in urine involves the use of hydrogel nanoparticles to concentrate urinary hGH obtaining detection limits (LOD) around pg mL –1 .…”

Diazonium-Modified Screen-Printed Electrodes for Immunosensing Growth Hormone in Blood Samples

“…A nano-integrated suspended polymeric microfluidics platform provided a detection limit of 2 ng/mL for the detection of bovine growth hormones [42]. A summary of articles [43,44,45,46,47,48,49,50,51,52] reporting the detection of GH using various surface modifications and detection techniques with limits of detection is presented in Table 1. Rezaei et al [45] modified gold electrodes with gold nanoparticles using 1,6-hexanethiol and managed to develop an ultrasensitive EIS-based immunosensor, which detected GH with a limit-of-detection of 0.64 pg/mL.…”

Magnetic Particles Coupled to Disposable Screen Printed Transducers for Electrochemical Biosensing

“…One year after, this same group prepared an electrochemical magnetoimmunosensor for the detection of human growth hormone (hGH) [16] involving the covalen immobilization of a monoclonal capture antibody on tosyl-activated MMPs, and the establishment of a sandwich-type immunoassay with a detector antibody coupled to a secondary labeled with AP. The sandwich magnetic immunoconjugates were captured on the surface of a screen-printed gold electrode (SPAuE) by means of a small magnet and, after addition of 4-aminophenyl phosphate as the AP substrate (Figure 1), square-wave voltammetry (SWV) was used for electrochemical detection.…”