Reflective interferometric Fourier-transform

Building on this work, the Sailor group employed their PSi-based reflective interferometric Fourier transform spectroscopy, or RIFTS, to detect a specific antibody-antigen interaction [48]. In this study, a two-layer PSi structure was etched with a high porosity layer on top of a lower-porosity layer (Fig. 6). Material and etching parameters were chosen such that the pore diameter was less than... 

Fig. 6 Reflective interferometric Fourier-transform spectroscopy (RIFTS) sensor. Sailor group. Adapted from [48]. Reflections produced by particular layer interfaces are characterized by A, B, and C only A and B are affected by analyte binding, while C is not...

Pacholski C, Yu C, Miskelly GM, Godin D, Sailor MJ (2006) Reflective interferometric Fourier transform spectroscopy a self-compensating label-free immunosensor using doublelayers of porous Si02. J Am Chem Soc 128 4250-4252... 

Orosco MM, Pacholski C, Miskelly GM, Sailor MJ (2006) Protein-coated porous silicon photonic crystals for amplified optieal detection of protease activity. Adv Mater 18 1393-1396 Pacholski C, Sartor M, Sailor MJ, Cunin F, Miskelly GM (2005) Biosensing using porous silicon double-layer interferometers reflective interferometric Fourier transform spectroscopy. J Am ChemSoc 127 11636-11645... 

Pace S, Vasani RB, Cunin F, Voeleker NH (2012a) Study of the optical properties of a thermoresponsive polymer grafted onto porous silicon scaffolds. New J Chem 37 228 Pace S, Seantier B, Belamie E, Lautredou N, Sailor MJ, Milhiet PE, Cunin F (2012b) Characterization of phospholipid bilayer formation on a thin film of porous Si02 by Reflective Interferometric Fourier Transform Spectroscopy (RIFTS). Langmuir 28 6960 Panek P (2004) Effect of macroporous silicon layer on opto-electrical parameters of multicrystalline silicon solar cell. Opto-Electron Rev 12 45... 

Hitherto, in the form of reflection-absorption infrared spectroscopy (RAIRS), the infrared method had been capable of detecting single monolayers only in the exceptionally favorable (strong absorption) cases of carboxylate ions [Francis and Ellison (14)] or carbon monoxide [Chesters, Pritchard, and Sims (15)] adsorbed on flat metal surfaces. The new challenge from VEELS provided the motivation for a search for improvements in RAIRS sensitivity, and this was very successfully achieved by M. A. Chesters and his colleagues through the introduction of Fourier-transform-based interferometric infrared spectroscopy (16). 

The properties of the dual-film electrode were characterized by in situ Fourier transform infrared (FTIR) reflection absorption spectroscopy [3]. The FTIR spectrometer used was a Shimadzu FTIR-8100M equipped with a wide-band mercury cadmium teluride (MCT) detector cooled with liquid nitrogen. In situ FTIR measurements were carried out in a spectroelectro-chemical cell in which the dual-film electrode was pushed against an IR transparent silicon window to form a thin layer of solution. A total of 100 interferometric scans was accumulated with the electrode polarized at a given potential. The potential was then shifted to the cathodic side, and a new spectrum with the same number of scans was assembled. The reference electrode used in this experiment was an Ag I AgCl I saturated KCl electrode. The IR spectra are represented as AR/R in the normalized form, where AR=R-R(E ), and R and R(E ) are the reflected intensity measured at a desired potential and a base potential, respectively. 

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