Redox molecule based SERS sensors.
We describe a general framework to design nanobiosensors based on a wired enzyme coupled to a redox molecule and integrated with SERS Au core-shell nanoparticles and ordered nanocavities. The response of the proposed sensor is based on the different electronic resonant Raman behavior of the oxidized or reduced electronic states of the molecular wire, and on the surface plasmon amplification induced by the tailored metallic substrate. The nanobiosensors can be interrogated remotely through the resonant Raman scattering intensity recovery or spectral variation of the redox molecule, an Os-complex, when the latter varies its oxidation state. Alternatively, we show through two-color spectro-electrochemistry that Raman scattering is also finely sensitive to oxidation state changes of flavin, a biomimetic system that mimics the active center of many flavoprotein enzymes. We show that multiple sample spectroscopic ellipsometry gives access to the spectral dependence of the optical constants of single redox-molecule layers, and through it to the electronic resonances of the system. All the components for selective molecular recognition and for the generation of an optical amplified signal, are self-contained in the proposed biosensor. As proof of concept a compact SERS sensor responsive to glucose with millimolar concentration in solution is demonstrated.
Tognalli
Nicolás G
NG
Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, 8400 S. C. de Bariloche, Río Negro, Argentina.
Scodeller
Pablo
P
Flexer
Victoria
V
Szamocki
Rafael
R
Ricci
Alejandra
A
Tagliazucchi
Mario
M
Calvo
Ernesto J
EJ
Fainstein
Alejandro
A
D015374:Biosensing Techniques; D008855:Microscopy, Electron, Scanning; D008958:Models, Molecular; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry; D009992:Osmium / Q000737:chemistry; D010084:Oxidation-Reduction; D011725:Pyridines / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods
D009942:Organometallic Compounds; D011725:Pyridines; D009992:Osmium; D012834:Silver; C023666:pyridine