A Photonic Crystal Protein Hydrogel Sensor for Candida albicans

Abstract

We report two-dimensional (2D) photonic crystal (PC) sensing materials that selectively detect Candida albicans (C.albicans). These sensors utilize Concanavalin A( Con A) protein hydrogels with a2 DP Ce mbedded on the Con A protein hydrogel surface,t hat multivalently and selectively bind to mannan on the C. albicans cell surface to form crosslinks.T he resulting crosslinks shrink the Con Ap rotein hydrogel, reduce the 2D PC particle spacing, and blue-shift the light diffracted from the PC.T he diffraction shifts can be visually monitored, measured with as pectrometer,o rd etermined from the Debye diffraction ring diameter.O ur unoptimized hydrogel sensor has adetection limit of around 32 CFU/ mL for C. albicans.T his sensor distinguishes between C. albicans and those microbes devoid of cell-surface mannan such as the gram-negative bacterium E. coli. This sensor provides aproof-of-concept for utilizing recognition between lectins and microbial cell surface carbohydrates to detect microorganisms in aqueous environments.

Visual Sensor for Sterilization of Polymer Fixtures Using Embedded Mesoporous Silicon Photonic Crystals

“…The culture was diluted to an optical density (OD) of 0.1 (measured at 600 nm), corresponding to 10 8 CFU/mL. 51,52 In order to assess the efficiency of sterilization of infected sensors, the culture was diluted to 2 × 10 6 CFU/mL and the devices were incubated in the mixture for 4 h. The samples were then rinsed briefly with water and scrubbed with a 70% isopropyl alcohol saturated swab (Webcol alcohol pads, Covidien) for 30–60 s, following the published protocol. 22 In order to assay for remaining live bacteria, the sample surface was thoroughly scraped with a heat sterilized inoculation loop and the bacteria collected in 200 μ L of sterile water.…”

Nanophotonics for bacterial detection and antimicrobial susceptibility testing

“…Different approaches have been used to improve resolution. In particular, the combination of 2D photonic crystals (PhCs) with hydrogels [76,77] has improved the resolution down to 32 CFU/mL of E. coli [77], although a number of complex preparation steps are required to achieve this result. An alternative way to improve the LOD is by using the field enhancement offered by PhCs to enhance fluorescence.…”

Sensors Based on Photonic Crystals

“…Сенсоры на основе ФК активно применяются для детектирования глюкозы [151,152], холестерина [153], для обнаружения макромолекул [154], в том числе белков [155], пектинов [156], ферментов (киназа) [157], а также диплоидного грибка Candida albicans [158].…”