A high-throughput integrated biofilm-on-a-chip platform for the investigation of combinatory physicochemical responses to chemical and fluid shear stress

Abstract

Physicochemical conditions play a key role in the development of biofilm removal strategies. This study presents an integrated, double-layer, high-throughput microfluidic chip for real-time screening of the combined effect of antibiotic concentration and fluid shear stress (FSS) on biofilms. Biofilms of Escherichia coli LF82 and Pseudomonas aeruginosa were tested against gentamicin and streptomycin to examine the time dependent effects of concentration and FSS on the integrity of the biofilm. A MatLab image analysis method was developed to measure the bacterial surface coverage and total fluorescent intensity of the biofilms before and after each treatment. The chip consists of two layers. The top layer contains the concentration gradient generator (CGG) capable of diluting the input drug linearly into four concentrations. The bottom layer contains four expanding FSS chambers imposing three different FSSs on cultured biofilms. As a result, 12 combinatorial states of concentration and FSS can be investigated on the biofilm simultaneously. Our proof-of-concept study revealed that the reduction of E. coli biofilms was directly dependent upon both antibacterial dose and shear intensity, whereas the P. aeruginosa biofilms were not impacted as significantly. This confirmed that the effectiveness of biofilm removal is dependent on bacterial species and the environment. Our experimental system could be used to investigate the physicochemical responses of other biofilms or to assess the effectiveness of biofilm removal methods.

Influence of Hydrodynamic Forces on Electroactive Bacterial Adhesion in Microbial Fuel Cell Anodes

“…In their recent study, Nguyen et al utilized a high-throughput microfluidic platform to investigate the combined effects of antibiotic concentration and fluid shear stress on biofilms. Their findings underscored the nuanced responses of biofilms to these factors, depending on bacterial species and environmental conditions, highlighting the pivotal role of shear stress in directing biofilm evolution in bioelectrochemical systems [12]. Pham et al found that applying a shear rate of 120 s −1 (approximately 120 mPa) resulted in increased power production of MFCs compared to a shear rate of 0.3 s −1 (approximately 0.3 mPa) [11].…”

A microscale system for in situ investigation of immobilized microalgal cell resistance against liquid flow in the early inoculation stage

“…In this regard, microfluidic devices have paved the way for studying the combined effect of reactor geometry and hydrodynamic conditions in a high-throughput manner. 16,17 Such a lab-on-a-chip device is also of great merit to precisely emulate the biological phenomenon on-line since its closed system design is able to cover a wide range of velocities applied to deposited cells without risking any unintended environmental effects. 18…”

“…In this regard, microfluidic devices have paved the way for studying the combined effect of reactor geometry and hydrodynamic conditions in a high-throughput manner. 16,17 Such a lab-ona-chip device is also of great merit to precisely emulate the biological phenomenon on-line since its closed system design is able to cover a wide range of velocities applied to deposited cells without risking any unintended environmental effects. 18 Therefore, the primary objective of this study is to employ a microfluidic device to evaluate the degree of cell detachment from fully-seeded supporting materials immersed in a flowing medium under varying shear liquid forces.…”

Ladder shaped microfluidic system enabling rapid antibiotic susceptibility testing with standardized concentration panel

“…Previous platforms using simple diffusion have produced continuous concentration gradients of antimicrobials 33,34 , but these approaches present a problem in determining the minimum inhibitory concentration (MIC) precisely. More recent platforms were successful at generating concentration gradients that are linear [33][34][35][36][37] ,logarithmic 35 , or sigmoidal 38 . Nevertheless, these techniques employ unstandardized concentration gradients.…”