| AVS 55th International Symposium & Exhibition | |
| BioMEMS Topical Conference | Tuesday Sessions |
| Session BM-TuP |
| Session: | BioMEMS |
| Presenter: | M.T. Meyer, University of Maryland |
| Authors: | M.T. Meyer, University of Maryland S.T. Koev, University of Maryland R. Fernandes, University of Maryland W.E. Bentley, University of Maryland R. Ghodssi, University of Maryland |
| Correspondent: | Click to Email |
Certain types of bacteria regulate gene expression through quorum-sensing, the detection of extracellular levels of bacterial signaling compounds. Once bacteria sense their population is sufficiently large to overwhelm a host’s immune system, they will aggregate and form a pathogenic matrix of bacteria, or biofilm. While this phenomenon is not fully understood, it is of interest to study biofilms to gain knowledge toward developing new antibacterial treatments. We have developed a platform for examining bacterial biofilm growth and response in a microfluidic environment using optical monitoring of selectively deposited Escherichia coli. Bacterial growth over time was quantified via optical absorbance using an external photodiode; the use of an optical sensor isolated from the fluidic environment allows for more reliable sensor operation as well as increased sensitivity. Two bacterial adhesion layers were investigated, including the amino-polysaccharide chitosan and a fusion protein (E72G3), consisting of a hydrophobic domain and an antibody-binding protein G domain, bound to antibodies against E. coli. E. coli cells were immobilized on electrodeposited chitosan, and biofilms were grown over a period of 48 hours. While chitosan can be selectively deposited and promotes bacterial adhesion, results show that material irregularities impede optical observation of the progression of biofilm growth. E72G3 was also used to immobilize E. coli by depositing the proteins on a patterned hydrophobic surface, then immobilizing antibodies against E. coli on E72G3. This method of bacterial deposition can be extended to numerous other pathogens by virtue of the fusion protein’s antibody-binding properties. Optically detectable biofilm formation was confirmed on this spatially and biologically selective surface. The platform can be used to quantify normal biofilm formation in addition to biofilm formation in response to external stimuli. Detailed device fabrication and testing parameters as well as experimental results will be presented. Our goal is to develop this platform into a fully integrated, compact device with highly parallel throughput for applications in discovering new antibacterial agents.