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.

Electrospray ionization is a routine method in MS analysis of proteins and other biopolymers. Deposition of the electrospray products onto a conductive electrode is suggested here as a means to manufacture functionally active protein films. Recovery of the specific hydrolytic activity of the electrosprayed alkaline phosphatase (AP) was used as a probe for preservation of protein intactness in the electrospray deposition (ESD). It was shown that protein inactivation upon ESD is highly dependent on voltage and current used. Humidity and the presence of protective substances in solution also affect the process. Complete preservation of the enzyme activity was observed when the ESD was performed at low current and humidity in the presence of disaccharides.

No abstract