IDBR: Type A: Development of a Polymer-Probe-Based Scanning Probe Microscope for Noninvasive, High-Speed, Broadband Investigation of Live Mammalian Cell

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This award to Rutgers University is being jointly made by two Programs- (1) Instrument Development for Biological Research, in the Division of Biological Infrastructure (Biological Sciences Directorate), and (2) Biophotonics, in the Division of Chemical, Bioengineering, Environmental and Transport Systems (Engineering Directorate). Scanning probe microscopy (SPM) is a technique that creates images of surfaces using a physical probe that scans the specimen. It provides researchers with unique capabilities of imaging, measuring, and manipulating single live cells and sub-cellular biological specimen on the same platform, with nanoscale spatial and force resolutions. The proposed research aims to develop a scanning probe microscope that overcomes limitations of commercially available devices that have "stiff" probes which are detrimental to creating 3D images of live biological specimens. The research outcomes of this IDBR award will be disseminated to the scientific community through (1) patent disclosure and licenses, (2) close collaboration with leading SPM companies, and (3) presentations in major cell biology, experimental biology, and biophysics conferences. The educational activities of the project include (1) Fostering multidisciplinary training by developing research based content for the curriculum in biology and engineering courses, (2) Recruitment and retention of under-represented students at the graduate and undergarduate level in the fields of biology and engineering, and (3) Outreach activities for middle- and high- school girls through open lab tours by leveraging the well-established programs at Rutgers (Rutgers Society for Women Engineers).Silicon-based cantilever probes universally used on all commercially available are too stiff and harsh to avoid deforming/damaging live biological surfaces (e.g., cell membrane), particularly for mammalian cells of large volume and soft and corrugated membrane. Moreover, both the contact-mode imaging protocol, currently the most effective mode for imaging single live cells in liquid, and the nanomechanical measurement protocol of open-loop nature, are not only prone to liquid-related disturbances and damage to the cell membrane, but also rather slow and narrow banded in imaging and measuring the nanomechanical properties of live cells. The project aims to overcome these limits through the development and integration of soft polymer-based cantilever probes, an adaptive imaging protocol of minimal deformation, and a control-based nanomechanical measurement protocol. The polymer-based cantilever will be designed and fabricated with contact stiffness and other mechanical properties tailored to SPM imaging and force interaction on mammalian cells. The imaging protocol of minimal-deformation will be developed based on an accurate quantification of the scanning-induced membrane deformation in real-time, to adaptively adjust both the scanning speed and the normal force to minimize membrane deformation and maximize the overall imaging efficacy. Then the control-based nanomechanical protocol is developed to completely remove the cantilever acceleration effect and substantially reduce the hydrodynamic force effect on the indentation measurement of live cells. The developed instrument will be evaluated and for its ability to quantify the viscoelasticity oscillation of cytoskeleton in real-time, and to quantify and correlate the morphological and mechanical evolutions of live cells during the cell division process.