Multiplexed determination of human growth hormone and prolactin at a label free electrochemical immunosensor using dual carbon nanotube–screen printed electrodes modified with gold and PEDOT nanoparticles

A label-free dual electrochemical immunosensor was constructed for the multiplexed determination of human growth (hGH) and prolactin (PRL) hormones. The immunosensor used an electrochemical platform composed of carbon nanotube–screen printed carbon electrodes (CNT/SPCEs) modified with poly(ethylene-dioxythiophene) (PEDOT) and gold nanoparticles, on which the corresponding hGH and PRL antibodies were immobilized. The affinity reactions were monitored by measuring the decrease in the differential pulse voltammetric oxidation response of the redox probe dopamine. The experimental variables involved in the preparation of both AuNP/PEDOT/CNT/SPC modified electrodes and the dual immunosensor were optimized. The immunosensor exhibited an improved analytical performance for hGH and PRL with respect to other electrochemical immunosensor designs, showing wide ranges of linearity and low detection limits of 4.4 and 0.22 pg mL−1, respectively. An excellent selectivity against other hormones and in the presence of ascorbic and uric acids was found. The usefulness of the dual immunosensor for the simultaneous analysis of hGH and PRL was demonstrated by analyzing human serum and saliva samples spiked with the hormones at different concentration levels.Ministerio de Economía y Competitividad (España)Depto. de Química AnalíticaFac. de Ciencias QuímicasTRUEpu

Micro- and nanotechnologies for study of cell secretion

Cell secretion or exocytosis is a fundamental and ubiquitous cell function in which intracellular vesicles (50-100 nm in diameter) fuse with the plasma membrane and release their content into the extracellular space. Constitutive exocytosis occurs constantly as a housekeeping activity to release proteins, metabolites, etc. Regulated exocytosis, on the other hand, is only triggered by specific stimuli to release signaling molecules. A classic example is Ca2+ triggered neurotransmitter secretion at neuronal synapses.Accepted versio