A surface acoustic wave biofilm sensor integrated with a treatment method based on the bioelectric effect

Abstract

Bacterial biofilms have an extensive impact on quality of life, ranging from severe infections in the clinical field to water facility contamination in environmental science. Biofilms are comprised of diverse bacteria that produce an extracellular matrix which prevents drug diffusion through them. Hence traditional antibiotic therapies require 500-5000 times the concentration used to eliminate non-biofilmassociated infections. Early biofilm detection is critical for effective eradication. Moreover, developing an alternative biofilm treatment method that utilizes low doses of antibiotics is desired. In this paper, a realtime microsystem is shown to detect growth of biofilms as well as their removal through integrated treatment. Detection of biofilms is achieved using a surface acoustic wave (SAW) sensor that monitors the total biomass by measuring the resonant frequency of the system. Biofilm treatment is based on the bioelectric effect (BE), a combination of low-dose antibiotics with application of both alternating and direct current signals. The detection limit of the SAW system is approximately 166 pg, corresponding to a bacterial population on the order of hundreds of bacteria. The system is used to observe an 80% reduction of total biomass when treated by the BE as compared to traditional antibiotics. Through system integration of the BE with the SAW sensor, simultaneous biofilm detection and treatment is achieved. The system consumes 194 µW of power, with the sensor and treatment consuming 100 µW and 94 µW, respectively. The integrated sensing and treatment capabilities of this system advance the development of an innovative biofilm control method.

Options and Limitations in Clinical Investigation of Bacterial Biofilms

“…One of the most recent setups for real-time E. coli and P. aeruginosa biofilm biomass growth evaluation was achieved through a sensing microsystem in which a microfluidic flow reactor employs a surface acoustic wave (SAW) sensor and electrodes constituting a source for current signals. This electric field is coupled with the use of gentamicin, and therefore this integrated sensing platform serves for biofilm growth monitoring and biofilm elimination (424). A novel impedimetric sensing system based on the interdigitated microelectrode microsystem envisions paving the way for the development of smart biosensors for rapid implant-associated biofilm identification and removal.…”

Surface acoustic wave devices for chemical sensing and microfluidics: a review and perspective

“…To date, a wide variety of biological targets have been studied, including proteins 86,87 , DNA 88 , and large cells and bacteria 89,90,91,92 , as well as biological warfare agents (BWAs) 93 and aflatoxins. 94 From a diagnostic and therapeutic perspective, there are multiple approaches that have been explored.…”

An optical microfluidic platform for spatiotemporal biofilm treatment monitoring

“…Additionally, a linear relationship between the energy of the applied electrical signal and the treatment efficacy of the BE was demonstrated [29]. We have also demonstrated real-time micro-scale detection of biofilm growth and inhibition when treated with the BE, using an integrated surface-acoustic-wave (SAW) microsystem [31] .…”