Towards a biosensor to monitor the sterilisation efficiency of aseptic filling machines

Abstract

Sterilisation processes are compulsory in medicine, pharmacy, and food industries to prevent infections of consumers and microbiological contaminations of products. Monitoring the sterilisation by conventional microbiological methods is time‐ and lab‐consuming. To overcome this problem, in this work a novel biosensor has been proposed. The sensor enables a fast method to evaluate sterilisation processes. By means of thin‐film technology the sensor's transducer structures in form of IDEs (interdigitated electrodes) have been fabricated on a silicon substrate. Physical characterisation of the developed sensor was done by AFM, SEM, and profilometry. Impedance analyses were conducted for the electrical characterisation. As microbiological layer spores of B. atrophaeus have been immobilised on the sensing structure; spores of this type are a well‐known sterilisation test organism. Impedance measurements at a fixed frequency over time were performed to monitor the immobilisation process. A sterilisation process according to aseptic filling machines was applied to demonstrate the sensor functionality. After both, immobilisation and sterilisation, a change in impedance could successfully be detected.

Impedimetric Biosensor to Enable Fast Evaluation of Gaseous Sterilization Processes

“…In order to reduce the laboratory workload a sensor-based method is preferable, to shorten the time delay after the process. In recent works, a sensor consisting of interdigitated electrodes has been developed to electrically characterize the impact of the sterilization process on immobilized, resilient test microorganism, such as spores of Bacillus atrophaeus [3,4]. The spore of this microorganism is applied to microbiologically evaluate sterilization processes in industry [5].…”

Optimization of the immobilization of bacterial spores on glass substrates with organosilanes

“…In addition, spores can be immobilized on biosensor substrates (e.g., glass) to serve as sensitive or recognition elements . The immobilization of the spores, however, is a critical factor; it may affect the sensitivity and reproducibility of the sensor signal.…”

“…A spore‐based biosensor was recently introduced to evaluate the sterilization process in aseptic filling machines. Such biosensor can be seen in Fig.…”

“…Spore‐based biosensor from Ref. . Differential set‐up of two chips with temperature sensors and IDEs.…”

Study of Interdigitated Electrode Arrays Using Experiments and Finite Element Models for the Evaluation of Sterilization Processes

“…The monitoring method is based on an impedimetric analysis of B. atrophaeus spores before and after the sterilization process. A sensor based on an interdigitated electrode (IDE) array has been developed to enable such analysis [ 7 ]. Instead of inoculating the surface of test packages, the indicator microorganisms are immobilized directly on the sensor surface.…”