Accurate real-time sensing tip for aqueous NO with optical fibers embedded in active hydrogel waveguide

Abstract

A NO sensing tip is made by inserting two parallel optical fibers inside a poly 2-hydroxyethyl methacrylate (PolyHEMA) hydrogel waveguide mixed with the probe molecule 1, 2-Diaminoanthraquinone (DAQ). There is a length difference of 1 mm between the two fibers, and the light has to propagate through the difference from the short fiber to the long fiber. The total cross section area of the active hydrogel waveguide embedded with the fibers is only 3mm x 1.2 mm. For practical use the tip is housed in a needle for mechanical protection and the sensing tip is able to detect aqueous NO concentration around 1 μM with time resolution about 5 minutes. Such a sensing tip can be used to monitor the medical conditions inside the brain after a stroke or a brain injury.

Hydrogel-integrated optical fiber sensors and their applications: a comprehensive review

“…13c). 362 When the probe molecule (DAQ) captured the target molecule (NO), it shifted the waveguide's resonance frequency and enabled signal detection. This fabricated 1.2 mm-diameter sensing tip identified changes in NO concentrations in about 5 min with a LOD of 1 μM with a resolution time of around 5 min.…”

Soft and Stretchable Optical Waveguide: Light Delivery and Manipulation at Complex Biointerfaces Creating Unique Windows for On-Body Sensing

“…Choi et al incorporated the rhodamine dye and biotin-conjugated fluorophores, respectively, into the PEG hydrogel optical fiber for biomedical applications, including in vivo optical sensing (Figure B–D) . Chung et al embedded 1,2-diaminoanthraquinone (DAQ) probe molecules in a hydrogel optical waveguide to detect NO in aqueous solution . This optical waveguide may help to monitor the health condition after brain injury consider the NO is a crucial neuromodulator.…”

“…Therefore, more and more researchers began to apply stimuli-responsive materials to the field of optical sensing. Stimuli-responsive optical waveguide materials are increasingly used in the field of optical sensings, such as detecting pH, − temperature, − enzyme, small molecules, ,− ion concentration, , etc. Yetisen et al report a phenylboronic acid-functionalized glucose-sensitive hydrogel flexible optical waveguide that can implement continuous glucose monitoring in vivo (Figure D) .…”

“…48 Chung et al embedded 1,2diaminoanthraquinone (DAQ) probe molecules in a hydrogel optical waveguide to detect NO in aqueous solution. 60 This optical waveguide may help to monitor the health condition after brain injury consider the NO is a crucial neuromodulator.…”