Improved Probe Tips for Biomedical Atomic Force Microscopy via Batch Wafer-Scale

点击翻译按钮获取中文摘要

Project Summary/Abstract This SBIR grant funds efforts to perfect and scale up a newly patented process for fabricating ultrasharp and hard probe tips for making images of biological specimens. Scanning probe microscopy (SPM) methods such as atomic force microscopy (AFM) create images of surfaces by rastering a probe across the surface. The probe itself consists of a tip (which interacts with the surface) and a body (which supports the tip and provides an externally-readable signal). The tip radius of curvature (ROC) determines the size of the smallest surface feature that may be imaged, and the tip composition establishes its hardness and thus its wear resistance. Currently, there is no known batch process to fabricate tips that are both extremely sharp (ROC < 5 nm) and hard (> 15 GPa). A new process invented at the University of Illinois solves these problems. The process involves two steps. First, chemical vapor deposition (CVD) is used to coat the tips with a chemically inert, highly conductive, and extremely hard material. Second, field directed sputter sharpening (FDSS) sharpens the probe tip to atomic dimensions (1- 4 nm radius of curvature at the tip apex). The current project will involve carrying out research to determine whether this process can be adapted for imaging biological samples, by applying various non-stick coatings to the probe tips. Probe tips that are ultrasharp, very hard, non-adherent, conductive, and relatively inexpensive will significantly enhance the capabilities of all those who use AFM to image non-conductive biological samples such as viruses, DNA, cell membranes and other cell structures, where static charge build-up limits efficacy and adhesion of foreign matter to the probe tip apex limits image resolution.