HP Innovation Journal Issue 10: Fall 2018 - Page 70

Figure 2 Major components of the HP Labs solution. RECONSTRUCT CELL STRUCTURES ROTATE CELLS Current technologies are expensive and require extensive training to manipulate. However, through cell spinning and different visualization techniques, we can enable biologists to quickly and easily examine cellular processes. Additionally, having the ability to spin live cells and create 3D models of them further improv es understanding of critical cellular events, including essential processes like cell division and transient occurrences like endo- and exocytosis. Furthermore, organelles and proteins can be fluorescently tagged in a live cell for visualization of distinct events like mitochondrial division, nuclear fragmentation, or trafficking of protein through the endoplasmic reticulum Golgi, to name a few. At HP Labs, we have introduced a solution that rotates cells in a microfluidic chip, then reconstructs 3D cell structures from the video sequence of cell spinning, and finally brings the digital model to physical reality through 3D printing (Figure 2). Figure 3 (a) Cell modeling results. Original video frame. Innovation Journal Issue Ten Figure 3 (b) Reconstructed 3D cell model. 3D PRINT MODEL MODELING 3D CELL STRUCTURES The hardware system consists of an electrode structure that produces a nonuniform electric field, which in turn applies a torque to a cell and rotates it. The spinning cell is then observed with an optical microscope in transmission, reflectance, fluorescence, or other modes, and an attached video camera records the rotating cells. As the cells rotate, we can observe them through multiple viewing angles. Having 2D object images from multiple observation angles leads to a 3D reconstruction problem based on Multi-View Geometry (MVG). Most existing MVG-based methods only reconstruct object surfaces. A surface mesh is then created as a result of obtaining and interpolating a dense point cloud. The biological structures we are interested in, such as cells, are normally transparent. We can see through the surface and observe structures within the cell membrane, which tells more about the cell. As a result, if Figure 4 Samples of 3D-printed cell models among assorted designs.