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

Abstract

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.

Recent advances in hybrid system of porous silicon nanoparticles and biocompatible polymers for biomedical applications

“…1a). Amongst many, the simplest method is the formulation of polymer-infiltrated pSi (A), where the polymer invades the entire pore of pSi [22][23][24][25]. After the nano-sized pores are filled with polymers, the formulations can be intensified by the covalent attachment between the pore walls and polymers.…”

Nanosilicon-Based Composites for (Bio)sensing Applications: Current Status, Advantages, and Perspectives

“…In [73,100], the authors reported on the visual colorimetric sensing techniques suitable for (bio)molecule detection. Photonic polymer modified PSi templates have shown prospective results for non-pathogenic E. coli and isopropanol alcohol detection.…”

“…These photonic PSi/polymer composites have also shown enhanced sensitivity to E. coli when compared with all-polymer photonic sensors. This can be attributed to differences in their wettability, which affects E. coli adhesion [100]. Ramakrishan et al reported on a PSi microcavity for autoimmune disease detection based on H 2 B antigens or antibodies quantification via red, green, and blue (RGB) spectral analysis (Figure 4).…”

Porous silicon pillar structures/photosynthetic reaction centre protein hybrid for bioelectronic applications

“…One of the most promising materials in this field is porous silicon (PSi), which is a widely used semiconductor with exceptional photonic [1], structural and electronic properties. Due to its unique properties and diverse structural design, PSi is an ideal candidate not only for optoelectronic devices [2,3] and novel drug delivery systems but also for chemical and biosensing applications [4][5][6][7][8][9][10][11][12].…”