U-shaped, double-tapered, fiber-optic sensor for effective biofilm growth monitoring.

Nianbing Zhong,Yishan Li,Mingfu Zhao

doi:10.1364/boe.7.000335

Abstract

To monitor biofilm growth on polydimethylsiloxane in a photobioreactor effectively, the biofilm cells and liquids were separated and measured using a sensor with two U-shaped, double-tapered, fiber-optic probes (Sen. and Ref. probes). The probes’ Au-coated hemispherical tips enabled double-pass evanescent field absorption. The Sen. probe sensed the cells and liquids inside the biofilm. The polyimide–silica hybrid-film-coated Ref. probe separated the liquids from the biofilm cells and analyzed the liquid concentration. The biofilm structure and active biomass were also examined to confirm the effectiveness of the measurement using a simulation model. The sensor was found to effectively respond to the biofilm growth in the adsorption through exponential phases at thicknesses of 0–536 μm.

Highlights

A biofilm consists of liquids and layers of cells embedded in a matrix consisting of a conglomeration of different types of biopolymers [1]
We examined the probes’ optical transmission characteristics, temperature responses, and sensitivities and checked the response speed of a reference (Ref.) probe coated with a prepared polyimide–silica hybrid film (PSHF)
The prepared fiber probes were placed in the channels of the PDMS membrane, and the BPBR was wrapped in opaque aluminum film and filled with distilled water at 30 °C

Summary

Introduction

A biofilm consists of liquids and layers of cells embedded in a matrix consisting of a conglomeration of different types of biopolymers (extracellular polymeric substances, EPSs) [1]. In the human organ system, biofilms can cause periodontal disease, dental caries, chronic bronchitis, pulmonary disease, and so on [2]; in the water industry, once biofilms are established, their toxic secretions can lead to severe infections that are difficult to treat, often requiring much greater concentrations of antibiotics than are necessary to treat bacterial suspensions [3]. These undesirable effects occur because the EPSs in biofilms increase their resistance to antibiotics and drugs [4]. Biofilm use is promising, the performances of photobioreactors using PSB are still very poor due to the current lack of effective and accurate biofilm thickness measurement and control [8]

Methods

Results

Conclusion