Dynamic Sessile‐Droplet Habitats for Controllable Cultivation of Bacterial Biofilm

Abstract

Bacterial biofilms play essential roles in biogeochemical cycling, degradation of environmental pollutants, infection diseases, and maintenance of host health. The lack of quantitative methods for growing and characterizing biofilms remains a major challenge in understanding biofilm development. In this study, a dynamic sessile-droplet habitat is introduced, a simple method which cultivates biofilms on micropatterns with diameters of tens to hundreds of micrometers in a microfluidic channel. Nanoliter plugs are utilized, spaced by immiscible carrier oil to initiate and support the growth of an array of biofilms, anchored on and spatially confined to the micropatterns arranged on the bottom surface of the microchannel, while planktonic or dispersal cells are flushed away by shear force of aqueous plugs. The performance of the aforementioned method of cultivating biofilms is demonstrated by Pseudomonas aeruginosa PAO1 and its derived mutants, and quantitative antimicrobial susceptibility testing of PAO1 biofilms. This method could significantly eliminate corner effects, avoid microchannel clogging, and constrain the growth of biofilms for long-term observations. The controllable sessile droplet-based biofilm cultivation presented in this study should shed light on more quantitative and long-term studies of biofilms, and open new avenues for investigation of biofilm attachment, growth, expansion, and eradication.

Surfactant-free production of biomimetic artificial cells using PDMS-based microfluidics

“…Recently, biofilms have been made within droplets that can be used for understanding biofilm growth, expansion, and even high-throughput screening. [35,36] Lipid vesicles that can be produced with ease using PDMS-based microfluidics will be a boon to either single cell growth studies or even development of organoids and biofilms for drug discovery. PDMS-based devices provide an additional advantage as the produced vesicles can be subsequent captured and analyzed in the same device.…”

Microfluidic devices for studying bacterial taxis, drug testing and biofilm formation

“…The second phase consisted of generating droplets of media to allow bacterial growth until biofilms developed. Adapted from (Jin et al., 2018 ). All figure panels were reproduced/adapted with permission from the corresponding publisher and/or journal.…”

“…8C ). In comparison with the microfluidic devices previously described, this approach eliminated corner effects and avoided channel plugs (Jin et al ., 2018 ). Biofilms have also been formed around oil droplets to study the interactions between bacteria and oil molecules that usually appear in flow environments.…”

An integrated microfluidic chip for alginate microsphere generation and 3D cell culture

“…[6][7][8] We consider that it is an important method to monitor and study pathogens in a controllable environment. 5,[9][10][11][12] To date, the conventional methods such as shake asks, 13,14 Petri dishes, 15 bioreactors 13 and multiwell plates 16 are still applied to culture and investigate pathogens. However, the operating procedures of conventional methods are complicated and time-consuming and can only provide limited control on pathogen culture.…”

“…Some research studies used droplets or lipid microspheres to provide a 3D environment for microbial cell culture. 5,9,11 Droplets and lipid microspheres are able to provide a sessile condition and are similar to hydrogel microspheres. However, hydrogel microspheres are much better because of their stability and biocompatibility.…”