Fiber-Optic Nitric Oxide-Selective Biosensors and Nanosensors

Abstract

Fiber-optic biosensors that are selective for nitric oxide and do not respond to most potential interferents have been prepared with cytochromes c'. Both micro- and nanosensors have been prepared, and their response is fast (< 1 s), reversible, and linear up to 1 mM nitric oxide. The detection limit is 20 microM, making the sensor useful for some biological samples, such as the macrophages studied here. While sensors have been prepared based on the fluorescence of the cytochromes c', optodes with greatly enhanced signal-to-noise ratios have been made by labeling the cytochrome c' with a fluorescent dye. Comparisons of cytochromes c' from three species of bacteria as well as of two matrixes were performed and the optimum sensor configuration is described.

Ligand-induced monomerization of Allochromatium vinosum cytochrome c′ studied using native mass spectrometry and fluorescence resonance energy transfer

“…For example, energy transfer from a fluorophore to a prosthetic heme group has been used to study protein interactions [30,31], folding dynamics [32,33], protein redox state [34] and ligand binding to the heme [14,31]. In the last two cases, changes in FRET are not due to a change in the distance between donor and acceptor, but are based on a change in spectral overlap.…”

“…Scientific interest in cytochromes c¢ has increased further owing to the similarities in spectral properties and ligand binding properties between cytochrome c¢ from Alcaligenes xylosoxidans and sGC [10,11]. Its CO and NO binding properties have been applied in electrochemical [12,13] and fiberoptic fluorescent biosensors [14,15]. Most cytochromes c¢ are isolated as stable homodimers, although some occur as monomers or as a mixture of both [16].…”

Miniature fiber-optic multicavity Fabry–Perot interferometric biosensor

“…For the layer structure shown in Figure 2.4, the composite cavity matrix can be expressed as 12 46) and from Eq. 2.22 the layer propagation matrices are 2 1 2 3 1 2 3 1 2 3 2 12 22 1 2 2 3 1 3 1 2 3 2 2 3 1 3 1 3 2 3 1 3 2 2 3 2 3 1 3 1 3 2 3 1 3 2 2 3 2 ( 1)cos( ) usually has a wavelength range of tens of nanometers.…”

Microfluidic and bio-applications of optical microfibres

“…Potassium [20] and Calcium [23] concentrations were detected using valinomycin and Fura-2/AM or fluo-3/AM calcium-dyes as highly-selective ligands. Other compounds measured in live cells include oxygen [24], nitrites [25], chloride ion [25] nitric oxide [26] and glutamate [27]. At the moment, the apex size is limited by the tip transmission efficiency.…”