סמינר המחלקה להנדסה ביו רפואית 28.04.19- הרצרת אורח של פרופ' אסתר סגל

On-chip rapid diagnostic susceptibility testing of bacteria and fungi from clinical samples

Ester Segal, Department of Biotechnology and Food Engineering, Technion

Employing rapid antimicrobial susceptibility testing (AST), which reliably predicts the success or failure of antimicrobial therapy, can significantly improve therapeutic management and reduce the instances of antibiotic resistance. We use functionalized photonic 2D silicon microarrays as  a platform for phenotypic susceptibility testing of both bacterial and fungal species. We harness the intrinsic ability of the micro-architectures to relay optical phase-shift reflectometric interference spectroscopic measurements (termed PRISM) and incorporate it into a platform for culture-free, label-free tracking of bacterial/fungal accumulation, proliferation, and death. The silicon arrays provide both a preferable solid-liquid interface for microorganisms networking and a simultaneous transducing element that monitors their response when exposed to antimicrobial agents in real time. This assay employs microfluidic channels interfaced with PRISM chips and is carried out in a two-stage process, namely bacteria/fungi seeding and antibiotic/antifungal incubation. In the latter step, bacterial/fungal proliferation within the chip is tracked in real time  by monitoring changes in the reflectivity spectra. For example, optical responses of bacteria to various concentrations of antibiotics have been tracked in real time, allowing for minimum inhibitory concentrations to be determined within only 30-120 minutes, compared to gold standard techniques and clinical automated systems with typical assay times > 8 hours. We further extended this work to analyze antibiotic susceptibilities of clinical isolates and direct urine and blood samples derived from patients  in newly designed microfluidic devices.