title: Nanoscale Manipulators: Review of Conceptual Designs Through Recent Patents.
abstract: BACKGROUND
  Nanomanipulation techniques have gone through several phases to be used in scientific explorations not only to reveal more characteristics of nano, micro and mesoscopic phenomena but also to build functional nano-devices useful for specific applications. The nano-manipulator becomes a key instrument for technology bridging between sub-nano and mesoscale. The recent patents have exhibited integration of various functions in the nano-devices requiring sub-nanometer precision and highly stable manipulator with substantial pulling/pushing forces. This work reviews patents and works on conceptual designs of existing nanomanipulators with specific features. This includes design analysis leading to ultra-precision motion and stability with discussion of enabling technology. A novel integrated and numerically controlled instrument for nanomanipulation, visualization and inspection/characterization of materials at sub-nanoscale will be presented with a feature to keep the same datum for all operation and hence improve accuracy of samples.
  
  
  METHODS
  This paper has undertaken a review search in a structured examination of bibliographic databases for published and issued patents using a focused review keyword of nano-manipulation. The quality of selected patents was appraised using standard tools. The characteristics of screened patents were described, and a deductive qualitative content analysis methodology was applied to understand the modeling and testing of nanomachining process, the exact construction of nanostructure arrays and the inspection of devices with complex features.
  
  
  RESULTS
  The paper encompassed forty patents. Fourteen patents exhibited the manipulation at the micro scale (MEMS manipulations), others outlined systems with sub-micron resolution and workspace range in mesoscale. Standard scale manipulation were described in 13 patents assuming only systems comprising positioning stages, arms and end-effectors where positioners are a few centimeters in size with workspace higher than one cm3. Finally, ten patents included in this review described the importance of end-effectors being extremely important in nanomanipulation as they do support the function defining the manipulation e.g. grippers, sprayers, Nano-tweezers.
  
  
  CONCLUSIONS
  The findings of this patents review confirm the relevance of the nanomanipulation of objects in 3D system coupled with real time imaging having higher resolution in comparison with the standard manipulators including AFM, TEM, STM, SEM or NSOM. In terms of tooling, AFM cantilever tips, etched tungsten tips or tips with electron beam deposition can be used to manufacture or develop nanodevices e.g. nanowires in in-situ SEM. In handling and manipulating in ambient conditions, commercial microfabricated grippers although available, are less used compared to CNT nanotweezers. Nanomanipulation is currently enabled for nanoscale samples by on-chip operations using promising MEMS and NEMS devices to relatively large samples by the meso and standard scale nanomanipulators. Manipulation is comprehensive and requires multiple functions enabled by various types of end-effectors and probes actuated with high precision. Piezo actuators are at the moment of great performance. Nano and sub-nano samples require proper environment e.g, with electron microscopy to monitor and manipulate including testing, inspecting and fabricating and assembling.
authors.affiliation: Mechanical Engineering Department, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia. smekid@kfupm.edu.sa.
authors.forename: Samir
authors.initials: S
authors.lastname: Mekid
authors.forename: Salem
authors.initials: S
authors.lastname: Bashmal
authors.forename: Hassen M
authors.initials: HM
authors.lastname: Ouakad