In Situ Stepwise Surface Analysis of Micropatterned Glass Substrates in Liquids Using Functional Near-Field Scanning Optical Microscopy

Abstract

Imaging of two adsorbed proteins on micropatterned glass substrates in air and liquid was conducted using atomic force microscopy (AFM) and near-field scanning optical microscopy (NSOM). The micropatterned glass substrates were prepared in five steps and evaluated by NSOM at each processing step. The micropatterned samples consisted of alternating 10 µm wide laminin stripes and 20 µm wide bovine serum albumin stripes. The samples containing both protein stripes were imaged "dry" (i.e., in air) using conventional contact AFM, then imaged dry with NSOM, and finally imaged in the hydrated form (i.e., in liquid) using NSOM. When samples were imaged in air, similar topographical features were observed using both AFM and NSOM. However, after the sample was rehydrated and imaged with NSOM in solution, the topography changed significantly. Having confirmed that the "real" surface topography was obtained while the proteins were in the hydrated form, in situ NSOM was used to detect changes in surface topography with nanometer resolution as a function of the micropatterning process. Although lithographic micropatterning provides chemical cues, in situ NSOM demonstrates that topographical cues are also an important aspect of the surface that serves to regulate cellular attachment and migration.

Localized electropolymerization on oxidized boron-doped diamond electrodes modified with pyrrolyl units

“…To accomplish E-SNOM (Fig. 6A) incorporating a tuning fork transducer 37,38 the most important feature is the design and construction of a probe tip, which can serve not only as a light source, but also as a nanoelectrode. We followed an approach described in the literature for nanoelectrode formation.…”

Oxygen Plasma-Treatment Effects on Si Transfer

“…Microcontact printing (μCP) , is a patterning technique that has been extensively used to produce well-defined, chemically specific patterns on a wide range of substrates. Its ease, cost-efficiency, and applicability to chemically different surfaces has made it an attractive alternative to other patterning methods, − such as photolithography, , which can be time-consuming and require specialized equipment not commonly found in a standard lab. In μCP, a patterned, elastomeric stamp is used to transfer molecules (i.e., “inks”) to a particular substrate, much like a regular “office stamp”, except that the raised features of the stamp have micrometer-sized dimensions.…”

Microscale Plasma-Initiated Patterning (μPIP)

“…Microscale patterning of biomolecules is used in a wide range of biological and medical applications including biosensors, DNA microarrays, tissue engineering, and immunoassays. − Methods to micropattern biomolecules onto both organic and inorganic surfaces include photolithography, ,, microcontact printing, ,,,,− micromolding in capillaries (MIMIC)/microfluidic networks, ,− and micromolding. , Each technique has relative advantages and limitations in terms of cost efficiency, ease, reproducibility, and applicability to specific ink/substrate combinations. For example, protein patterns by microcontact printing requires that the protein molecules interact with the final substrate more strongly than with the micropatterned stamp that is first inked with the biomolecules .…”

“…Microscale patterning of biomolecules is used in a wide range of biological and medical applications including biosensors, DNA microarrays, tissue engineering, and immunoassays. [1][2][3][4][5][6] Methods to micropattern biomolecules onto both organic and inorganic surfaces include photolithography, 1,3,7 microcontact printing, 1,2,5,6,[8][9][10][11][12] micromolding in capillaries (MIMIC)/microfluidic networks, 1,[13][14][15][16] and micromolding. 1,17 Each technique has relative advantages and limitations in terms of cost efficiency, ease, reproducibility, and applicability to specific ink/substrate combinations.…”