Jeffrey Blyth

Holographic Sensors: Three-Dimensional Analyte-Sensitive Nanostructures and Their Applications

Nanostructures and Their Applications Ali K. Yetisen,*,† Izabela Naydenova,‡ Fernando da Cruz Vasconcellos,† Jeffrey Blyth,† and Christopher R. Lowe† †Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QT, United Kingdom ‡Centre for Industrial and Engineering Optics, School of Physics, College of Sciences and Health, Dublin Institute of Technology, Dublin 8, Ireland

Reusable, robust, and accurate laser-generated photonic nanosensor.

Developing noninvasive and accurate diagnostics that are easily manufactured, robust, and reusable will provide monitoring of high-risk individuals in any clinical or point-of-care environment. We have developed a clinically relevant optical glucose nanosensor that can be reused at least 400 times without a compromise in accuracy. The use of a single 6 ns laser (λ = 532 nm, 200 mJ) pulse rapidly produced off-axis Bragg diffraction gratings consisting of ordered silver nanoparticles embedded within a phenylboronic acid-functionalized hydrogel. This sensor exhibited reversible large wavelength shifts and diffracted the spectrum of narrow-band light over the wavelength range λpeak ≈ 510-1100 nm. The experimental sensitivity of the sensor permits diagnosis of glucosuria in the urine samples of diabetic patients with an improved performance compared to commercial high-throughput urinalysis devices. The sensor response was achieved within 5 min, reset to baseline in ∼10 s. It is anticipated that this sensing platform will have implications for the development of reusable, equipment-free colorimetric point-of-care diagnostic devices for diabetes screening.

A diffusion method for making silver bromide based holographic recording material

AbstractA simple diffusion method for the distribution of ultrafine silver bromide grains in pre-coated gelatin and customized polymeric films for holographic recording has been developed. The method involves two steps: immersion of the pre-formed film in a solution of a silver salt, followed by agitation of the film in a solution of a bromide salt containing sensitizing dye. Repetition of the operation on the same film with different sensitizing dyes in the bromide bath enables the production of film with a panchromatic response. Transmission electron microscopy reveals a grain structure very suitable for use in holography. A reflection hologram made by this method has a similar brightness under the same exposure and processing conditions to one made from a proprietary hologram recording material currently available.