Biomedical subjects

Henryk Szmacinski

Publications and source records attributed to Henryk Szmacinski.

3 recordsLinked to original sources

PubMed2005

Enhanced ratiometric pH sensing using SNAFL-2 on silver island films: metal-enhanced fluorescence sensing.

We have explored the opportunities for enhanced ratiometric pH sensing using the well-known carboxy seminaphthofluorescein (SNAFL-2) and silver island films (SiFs). Our results show that the metallic surfaces can provide up to a 40-fold increase in probe fluorescence intensity as compared to nonmetallic surfaces with the same probe coverage. However, while the S/N is significantly better for pH sensing, the emission wavelength ratiometric values are similar to that obtained in solution, due to the fact that the emission of both the acidic and basic forms of the probe are enhanced to similar extents. To the best of our knowledge this is the first report of enhanced ratiometric fluorescence sensing on metallic surfaces.

Fluoresceins↗

PubMed2004

Metal-enhanced fluorescence solution-based sensing platform.

In recent years our laboratories have reported the favorable effects for fluorophores placed in close proximity to surface immobilized silver nanostructures. These include; greater quantum yields, reduced lifetimes (increased photostability) and directional emission. However, while these findings are likely to find multifarious applications for surface assays based on enhanced fluorescence detection, a solution based enhanced sensing platform has yet to be realized. In this short, note, we show how SiO2-coated silver colloids, indeed provide for a solution based enhanced fluorescence sensing platform with a 3-5 fold enhancement typically observed.

Colloids↗

PubMed2003

Submicrometer spatial resolution of metal-enhanced fluorescence.

Enhanced fluorescence emission intensity from fluorescein was observed on glass slides covered with thin films of silver nanoparticles using a confocal laser-scanning microscope. The silver nanoparticle film increased the emission intensity of fluorescein by an average of at least three-fold in the area studied. Statistics are given on the enhancement of individual areas of the silver particle film with a resolution of approximately 210 nm. A histogram of intensity values indicates that the enhancement appears to occur without distinct subpopulations, with the exception that very high intensity subpopulations may occur but could not be resolved. Spatial features with dimensions near or smaller than the resolution limit of the confocal microscope, on the silver nanoparticle slide that enhanced the emission of fluorescein, were found using autocorrelation functions. These spatial features are of the same size as those found from the emission of slides containing silver nanoparticles only. These spatial features do not appear in control slides containing fluorescein without any silver nanoparticles. No long-range spatial ordering of the fluorescence enhancement on chemcially deposited silver nanoparticle slides was detected.

Avidin↗