title: Hybrid organic/inorganic interfaces as reversible label-free platform for direct monitoring of biochemical interactions.
abstract: The combination of organic and inorganic materials to create hybrid nanostructures is an effective approach to develop label-free platforms for biosensing as well as to overcome eventual leakage current-related problems in capacitive sensors operating in liquid. In this work, we combine an ultra-thin high-k dielectric layer (Al2O3) with a nanostructured organic functional tail to create a platform capable of monitoring biospecific interactions directly in liquid at very low analyte concentrations. As a proof of concept, a reversible label-free glutathione-S-transferase (GST) biosensor is demonstrated. The sensor can quantify the GST enzyme concentration through its biospecific interaction with tripeptide reduced glutathione (GSH) bioreceptor directly immobilized on the dielectric surface. The enzymatic reaction is monitored by electrical impedance measurements, evaluating variations on the overall capacitance values according to the GST concentration. The biosensor surface can be easily regenerated, allowing the detection of GST with the very same device. The biosensor shows a linear response in the range of 200pmolL-1to 2µmolL-1, the largest reported in the literature along with the lowest detectable GST concentration (200pmolL-1) for GST label-free sensors. Such a nanostructured hybrid organic-inorganic system represents a powerful tool for the monitoring of biochemical reactions, such as protein-protein interactions, for biosensing and biotechnological applications.
authors: Brazilian Nanotechnology National Laboratory (LNNano), CNPEM, Campinas, 13083-970 Brazil; Department of Physical Chemistry, Institute of Chemistry, University of Campinas, P.O. Box 6154, Campinas, SP, 13084-862 Brazil.
authors: Tatiana P
authors: TP
authors: Vello
authors: Brazilian Nanotechnology National Laboratory (LNNano), CNPEM, Campinas, 13083-970 Brazil.
authors: Larissa M B
authors: LMB
authors: da Silva
authors: Brazilian Nanotechnology National Laboratory (LNNano), CNPEM, Campinas, 13083-970 Brazil.
authors: Gustavo O
authors: GO
authors: Silva
authors: Brazilian Nanotechnology National Laboratory (LNNano), CNPEM, Campinas, 13083-970 Brazil.
authors: Davi H S
authors: DHS
authors: de Camargo
authors: Brazilian Nanotechnology National Laboratory (LNNano), CNPEM, Campinas, 13083-970 Brazil.
authors: Cátia C
authors: CC
authors: Corrêa
authors: Brazilian Nanotechnology National Laboratory (LNNano), CNPEM, Campinas, 13083-970 Brazil; Department of Physical Chemistry, Institute of Chemistry, University of Campinas, P.O. Box 6154, Campinas, SP, 13084-862 Brazil; Institute of Physics "Gleb Wataghin" (IFGW), UNICAMP, Campinas, 13083-859 Brazil. Electronic address: cesar.bof@lnnano.cnpem.br.
authors: Carlos C
authors: CC
authors: Bof Bufon
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation*; D004566:Electrodes; D057075:Enzyme Assays / Q000295:instrumentation*; D004867:Equipment Design; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism; D005982:Glutathione Transferase / Q000032:analysis* / Q000378:metabolism; D006736:Horses; D049329:Nanostructures / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry
chemical_list: D009532:Nickel; D005982:Glutathione Transferase; D005978:Glutathione; D000537:Aluminum Oxide
keywords: Biosensor; Glutathione S-transferase; Hybrid organic-inorganic nanostructures; Solid-liquid interfaces