Toward Multiplexing Detection of Wound Healing Biomarkers on Porous Silicon Resonant Microcavities

Abstract

Bacterial wound infections can cause septicemia and lead to limb amputation or death. Therefore, early detection of bacteria is important in chronic wound management. Here, an optical biosensor based on porous silicon resonant microcavity (pSiRM) structure modified with fluorogenic peptide substrate is demonstrated to detect the presence of Sortase A (SrtA), a bacterial enzyme found in the cell membrane protein of Staphylococcus aureus. The combination of fluorescence enhancement effects of the pSiRM architecture with the incorporation of SrtA fluorogenic peptide substrate within the pSi matrix enables the sensing of SrtA with an outstanding limit of detection of 8 × 10−14 m. Modification of the pSiRM structure with microscale spots of two fluorogenic peptide substrates, one specific for SrtA and the other for matrix metalloproteinases, effectively demonstrates the feasibility to perform multiplexed biomarker analysis. The results in this study highlight the potential of the pSiRM sensing platform as a point‐of‐care diagnostic tool for biomarkers of bacterial wound infection.

Label-Free Optical Resonator-Based Biosensors

“…A porous silicon microcavity (PSM) is an FPI structure created by two DBRs with a thin layer of porous silicon (PS). PS is inexpensive, easy to fabricate, and has a large sensing surface, so it has been widely investigated to develop label-free optical biosensors [ 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ]. The refractive index of a PS layer is determined by the porosity, which can be modulated by adjusting parameters of electrochemical etching such as the etching time and current density.…”

Porous Silicon Optical Devices: Recent Advances in Biosensing Applications

“…Macroporous and mesoporous Si are commonly employed as biosensing platforms to allow the attachment of biomolecules within their matrices. The capture of analytes can be monitored via reflectance, when dealing with macroporous or mesoporous structures (i.e., monolayer, Bragg mirror) [ 37 , 38 ], or via photoluminescence with mesoporous matrices (i.e., resonant microcavity, nanowires) [ 39 , 40 ]. Unfortunately, the intrinsic PL of PSi is usually unstable, since it strongly depends on the surrounding chemical environment that can influence its intensity [ 11 ].…”

Porous Alumina Membrane-Based Electrochemical Biosensor for Protein Biomarker Detection in Chronic Wounds

“…Such sensor could become the basis of a POC device for chronic wound care. Several sensors to assess wound healing progression have been developed, targeting infection, pH, oxygen, uric acid, hemoglobin, and broad-spectrum proteases (Dargaville et al, 2013;Edwards et al, 2013;Sharp, 2013;Krismastuti et al, 2014Krismastuti et al, , 2015aKrismastuti et al, , 2017Ochoa et al, 2014;Salvo et al, 2015;Jankowska et al, 2017;RoyChoudhury et al, 2018). These sensors have not reached yet the stage of deployment in the clinic due to the challenges involved, such as the complex wound environment with hundreds of proteins present in a wide pH range.…”