Flow-through photonic crystal sensor for rapid endotoxin detection

Overview

This solution offers a rapid, sensitive optical sensor for detecting endotoxin in fluid samples. The flow-through photonic crystal (FT-PC) sensor is designed to be integrated directly into IV tubing, providing real-time measurement of endotoxin levels. By forcing the entire sample through a porous membrane rather than across its surface, the sensor overcomes mass transport limitations that slow conventional assays. The disposable design makes it well suited for clinical and bioprocessing environments where sterility and single-use workflows are essential.

Technical specifications

• Membrane architecture: 5-mm-diameter anodized aluminum oxide (Al2O3) membrane featuring an array of uniform 500-nm through-holes that act as a photonic crystal.
• Optical readout: The porous PC reflects light at a characteristic resonance wavelength; shifts in this wavelength are recorded in real time to quantify endotoxin binding.
• Surface chemistry: The PC membrane is functionalized with an anti-endotoxin antibody that selectively captures endotoxin from the flowing sample.
• Flow design: Saline and test samples are pumped through the membrane, ensuring every analyte molecule has an opportunity to interact with the capture surface.
• Manufacturing process: A low-cost nano-molding technique patterns thin aluminum foils, which are then anodized to produce periodic Al2O3 PC structures with through-membrane pores.
• System integration: The disposable sensor is packaged with inlet and outlet connectors compatible with IV tubing, paired with a compact optical reader that monitors resonance wavelength shifts to determine absorbed endotoxin concentration.

Technology readiness level

The underlying flow-through optical sensing approach has been validated by the research lab in prior work, including a silicon-based FT-PC sensor used to detect breast cancer biomarkers in blood with shorter assay times and higher sensitivity than flow-over counterparts. The nano-molding fabrication process, surface functionalization chemistry, and flow controller components are already in place. The two-year development plan moves the technology through three stages: fabrication and optical characterization of the Al2O3 FT-PC, validation of endotoxin analytical performance (dynamic range, limit of detection, specificity, and response time), and integration of the sensor into IV tubing with a prototyped compact optical reader.