Electrospray Deposition as a Method for Mass Fabrication of Mono- and Multicomponent Microarrays of Biological and Biologically Active Substances

Abstract

Electrospray of protein and DNA solutions is currently used to generate ions for mass spectrometric analysis of these molecules. Deposition of charged electrospray products on certain areas of a substrate under control of electrostatic forces is suggested here as a method for fabrication of multiple deposits of any size and form. For example, multiple dots of protein, DNA, or other organic substances can be deposited simultaneously through an array of holes in a dielectric mask covering any slightly conductive substrate (membrane, wet glass, semiconductor, etc.). If every new substance is deposited after a shift of the mask with respect to the substrate, a multicomponent matrix is created under each hole. It is demonstrated that dots as small as 2-6 microns can be fabricated by such an electrospray deposition (ESD). It is also demonstrated that the ES-deposited proteins and DNA retain their ability to specifically bind antibodies and matching DNA probes, respectively, enabling use of the ESD fabricated matrixes in Dot Immuno-Binding (DIB) and in DNA hybridization assays.

Scaling laws for jet pulsations associated with high-resolution electrohydrodynamic printing

“…We choose the diameter of the jet d for l 2 and d N for l 1 because the surface tension acts on the entire area defined by the nozzle, while the electric field mainly focuses at the apex of the cone. 18,19 The quantity d N can correspond to an anchoring diameter at the nozzle tip.…”

Focused Electrospray Deposition for Matrix-assisted Laser Desorption/Ionization Mass Spectrometry

“…15 To this end, we need to focus charged droplets onto a spot under atmospheric pressure. A number of electrostatic lens assemblies have been reported to date for collimating charged droplets from electrospray ionization (ESI) source: [23][24][25][26][27] An ion funnel 23 collimates ions under vacuum after passing through a sampling capillary. A venturi device increases the transmission efficiency of ions through a sampling orifice under atmospheric pressure.…”

Micro patterning of active proteins with perforated PDMS sheets (PDMS sieve)

“…This problem is referred as "non-specific binding" which makes it difficult to fasten the molecules only to specific locations on the substrate. 8,11 Physical methods such as micro-contact printing [12][13][14] or spraying deposition methods 15 ensure that the molecules do not spread to other locations. However, these methods cause the proteins to dry out or degenerate.…”