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

A porous
photonic crystal is integrated with a plastic medical
fixture (IV connector hub) to provide a visual colorimetric sensor
to indicate the presence or absence of alcohol used to sterilize the
fixture. The photonic crystal is prepared in porous silicon (pSi)
by electrochemical anodization of single crystal silicon, and the
porosity and the stop band of the material is engineered such that
the integrated device visibly changes color (green to red or blue
to green) when infiltrated with alcohol. Two types of self-reporting
devices are prepared and their performance compared: the first type
involves heat-assisted fusion of a freestanding pSi photonic crystal
to the connector end of a preformed polycarbonate hub, forming a composite
where the unfilled portion of the pSi film acts as the sensor; the
second involves generation of an all-polymer replica of the pSi photonic
crystal by complete thermal infiltration of the pSi film and subsequent
chemical dissolution of the pSi portion. Both types of sensors visibly
change color when wetted with alcohol, and the color reverts to the
original upon evaporation of the liquid. The sensor performance is
verified using E. coli-infected samples.