A nanostructured immunosensor based on the liquid crystal (E)-1-decyl-4-[(4-decyloxyphenyl)diazenyl]pyridinium bromide (Br-Py) and gold nanoparticles supported by the water-soluble hybrid material 3-n-propyl-4-picolinium silsesquioxane chloride (AuNP-Si4Pic(+)Cl(-)) was built for the detection of troponin T (cTnT), a cardiac marker for acute myocardial infarction (AMI). The functionalized nanostructured surface was used to bind anti-cTnT monoclonal antibodies through electrostatic interaction. The immunosensor (ab-cTnT/AuNP-Si4Pic(+)Cl(-)/Br-Py/GCE) surface was characterized by microscopy techniques. The electrochemical behavior of the immunosensor was studied by cyclic voltammetry and electrochemical impedance spectroscopy. A calibration curve was obtained by square-wave voltammetry. The immnunosensor provided a limit of detection of 0.076 ng mL(-1) and a linear range between 0.1 and 0.9 ng mL(-1) (appropriate for AMI diagnosis).