Developing a Novel Terahertz Fabry–Perot Microcavity Biosensor by Incorporating Porous Film for Yeast Sensing

Abstract

We present a novel terahertz (THz) Fabry–Perot (FP) microcavity biosensor that uses a porous polytetrafluoroethylene (PTFE) supporting film to improve microorganism detection. The THz FP microcavity confines and enhances fields in the middle of the cavity, where the target microbial film is placed with the aid of a PTFE film having a dielectric constant close to unity in the THz range. The resonant frequency shift increased linearly with increasing amount of yeasts, without showing saturation behavior under our experimental conditions. These results agree well with finite-difference time-domain (FDTD) simulations. The sensor’s sensitivity was 11.7 GHz/μm, close to the optimal condition of 12.5 GHz/μm, when yeast was placed at the cavity’s center, but no frequency shift was observed when the yeast was coated on the mirror side. We derived an explicit relation for the frequency shift as a function of the index, amount, and location of the substances that is consistent with the electric field distribution across the cavity. We also produced THz transmission images of yeast-coated PTFE, mapping the frequency shift of the FP resonance and revealing the spatial distribution of yeast.

Real-Time Detection of Yeast Growth on Solid Medium through Passive Microresonator Biosensor

“…For instance, Tamra introduced a 40 GHz microwave biosensor designed for monitoring and characterizing single cells (THP-1) during electrochemotherapy, capturing an electronic signature indicative of treatment efficacy [27]. Kim's contribution to the field includes a novel terahertz (THz) Fabry-Perot (FP) microcavity biosensor, employing a porous polytetrafluoroethylene (PTFE) film to enhance microorganism detection [28]. Despite these advancements, the application of microwave biosensors for real-time microbial growth monitoring on solid media remains less explored compared to their use for solution concentration and cell count assessments.…”

Mechanical Control of Polaritonic States in Lead Halide Perovskite Phonons Strongly Coupled in THz Microcavity

“…Briefly, we coated the MAPbI 3 films using a spin-coating process, with the film thickness varying from 250 nm to 1.67 μm. The FSP film was transferred to the FP cavity, and the partial mirror of the cavity was fabricated by spin-coating PEDOT:PSS on silicon or polypropylene (PP) plastic for flexible devices Figure c illustrates the photograph of the FSP film.…”