Scanning Probe Microscope-Based Fluid Dispensing

Abstract

Advances in micro and nano fabrication technologies have enabled fabrication of smaller and more sensitive devices for applications not only in solid-state physics but also in medicine and biology. The demand for devices that can precisely transport material, specifically fluids are continuously increasing. Therefore, integration of various technologies with numerous functionalities in one single device is important. Scanning probe microscope (SPM) is one such device that has evolved from atomic force microscope for imaging to a variety of microscopes by integrating different physical and chemical mechanisms. In this article, we review a particular class of SPM devices that are suited for fluid dispensing. We review their fabrication methods, fluid-pumping mechanisms, real-time monitoring of dispensing, physics of dispensing, and droplet characterization. Some of the examples where these probes have already been applied are also described. Finally, we conclude with an outlook and future scope for these devices where femtolitre or smaller volumes of liquid handling are needed.

A Comparative Study of Thiol‐Terminated Surface Modification by Click Reactions: Thiol‐yne Coupling versus Thiol‐ene Michael Addition

“…However, when choosing coupling reactions in other arraying technologies like dip‐pen nanolithography (DPN), inkjet printing or needle printing, size differences in resulting features (leading to different volumes in the deposited droplets acting as reaction vessels on the surface) must be kept in mind. The deposited volumes range over several orders of magnitude from DPN (low attoliter) to inkjet printing (pico‐ to nanoliter), with µCS (low femtoliter) being in the middle of this range . These size differences are expected to also effect chemical reactions inside the droplets and at the droplet/surface interface due to convection, diffusion length, and drying effects .…”

Fabrication Process of Embedded Silicon Microchannel and Nozzle Structure for Liquid-delivering Atomic Force Microscopy Probe

“…Also, in the case of a microchannel with a small diameter, a hydrophilic inner wall is preferred for smooth liquid flow. (10) Figure 6(a) shows an example in which the trench (700 nm wide) was completely sealed by the wet thermal oxidation (1100 ℃) of a Si film with a thickness of 880 nm. A 660-nm-thick thermal oxide film was also formed on the inner wall of the microchannel.…”

Multiscale 3D-printing of microfluidic AFM cantilevers

“…14,15 With the advent of the FluidFM technique, 16 simultaneous precise force control and (sub)picolitre volume fluid manipulation inside a cell has become possible. [17][18][19][20] The technique uses an AFM cantilever with an internal channel and aperture at the tip. These hollow microcantilever probes are fabricated by standard clean room microfabrication techniques with nanometer precise control over their shape and size.…”