Bacterial Cell Cultures in a Lab-on-a-Disc: A Simple and Versatile Tool for Quantification of Antibiotic Treatment Efficacy

Abstract

Pathogenic bacterial biofilms can be life threatening, greatly decrease patients' quality of life and are a substantial burden on the healthcare system. Current methods for evaluation of antibacterial treatments in clinics and in vitro systems used in drug development and screening either do not facilitate biofilm formation or are cumbersome to operate, need large reagent volumes and are costly, limiting their usability. To address these issues, this work presents the development of a robust in vitro cell culture platform compatible with confocal microscopy. The platform shaped as a compact disc, facilitates long-term bacterial culture without external pumps and tubing and can be operated for several days without additional liquid handling. As an example, Pseudomonas aeruginosa biofilm is grown from single cells and it is shown that: 1) the platform delivers reproducible and reliable results; 2) growth is dependent on flow rate and growth medium composition; and 3) efficacy of antibiotic treatment depends on the formed biofilm. This platform enables biofilm growth, quantification and treatment as in a conventional flow setup, while decreasing the application barrier of lab-on-chip systems. It provides an easy-to-use, affordable option for end users working with cell culturing in relation to e.g. diagnostics and drug screening.

Enhanced Eradication of Mucin‐Embedded Bacterial Biofilm by Locally Delivered Antibiotics in Functionalized Microcontainers

“…[ 60 ] In an earlier study, we showed that PAO1 can be cultured for up to 72 h (flow rate of 1 µL min −1 ) in 100 times diluted ASM in the BCoD. [ 50 ] The length of culture time is adjustable. Usually, in glucose minimal medium, PAO1 requires 2–4 days to develop a mature biofilm.…”

“…Usually, in glucose minimal medium, PAO1 requires 2–4 days to develop a mature biofilm. [ 61 ] Moreover, the flow rate was found optimal in the BCoD platform [ 50 ] as it provides sufficient amounts of nutrients and oxygen to support a multilayered biofilm development.…”

“…The centrifugal microfluidic‐based in vitro system, the bacterial culture on disc (BCoD) platform (Figure 1B), provides a unique possibility to perform studies on biofilms embedded in mucin (Figure 1C), often unachievable with commonly available in vitro platforms. [ 50 ] Earlier in the BCoD system, it has been showed that P. aeruginosa (PAO1) biofilm can be grown under flow condition in a diluted artificial sputum medium (ASM) with reduced nutrient and mucin content, [ 50 ] to better mimic a microenvironment closer to the in vivo one as for example in the sputum of cystic fibrosis patients. [ 51 ] As other microfluidic systems, the BCoD works with small reagents volumes (from µL to few mL), enabling the use of complex and expensive growth media such as ASM, and additionally does not necessitate the use of auxiliary pumps.…”

“…[ 51 ] As other microfluidic systems, the BCoD works with small reagents volumes (from µL to few mL), enabling the use of complex and expensive growth media such as ASM, and additionally does not necessitate the use of auxiliary pumps. [ 50 ] Pumps and tubing introduce additional reagent consumption, therefore, the BCoD is ideal for minimizing reagent consumption and optimizing growth conditions. In the BCoD, the antimicrobial activity of the developed CHI/NAC and CHI‐functionalized MCs is compared to bulk delivery of unconfined antibiotics.…”

Microsystems for biofilm characterization and sensing – A review

“…developed centrifugal microfluidic devices which do not rely on external pumps to drive flow have been used to study the impact of shear on Pseudomonas aeruginosa with low sample volumes and increased ease of use. The Lab on a Disc platform simply uses a spinning motor to create the desired flow conditions within the device [ 90 ].…”