A Highly Parallel Nanoliter Dispenser for Microarray Fabrication

Abstract

We report about the correlation between satellite free droplet release and liquid viscosity in a highly parallel, pressure driven nanoliter dispenser. In extensive studies, we found that for liquids of different viscosities the duration of the pressure pulse is the predominant effect compared to pressure amplitude. This result is of essential importance when actuation parameters have to be adopted for different media like oligonucleotide, DNA or protein solutions as it is the case for the non-contact high throughput fabrication of microarrays (Ducree et al., 2000). Experiments with oligonucleotides as well as with different proteins showed ascertained carry-over and cross-contamination free printing of DNA and protein microarrays. With it a prime critical point of microarray production is solved, leading to high quality whilst high throughput microarray fabrication. For oligonucleotides printing, we found CVs to be better than 1% within one single dispensing channel and 1.5% within all 24 channels of a 24 channel printhead for each used printing buffer. By optimizing the protein printing buffer the CVs for protein printing were reduced to about 1% within all 24 channels. As a serious practical application test oligonucleotides microarrays were produced using our nanoliter dispenser system. With it a full DNA hybridization experiment was performed. Clear positive signals one hand and no signals in the negative controls on the other hand showed that our system is suited for microarray production.

Bio-Microarray Fabrication Techniques—A Review

“…Another non-contact printing technique similar to ESD is a Scanning Probe Microscopy (SPM) technique 11,20,22 based on scanning ion conductance microscopy. This technique allows for depositing nano-spots by applying an electrical field pulse between the substrate and a nano-pipette that is filled with sample ( Figure 23).…”

DNA Microarrays

“…Figure 5 shows a onenozzle non-contact pipette releasing a drop on demand. This kind of pipette may also be used for a variety of different pipetting procedures where small A microsystem approach has been made by Zengerle and coworkers [18,19] which they named "TopSpot". An array of nozzles is produced in a monolithic manner using Si-wafer technology.…”

An equipment-free polydimethylsiloxane microfluidic spotter for fabrication of microarrays

“…These challenges include the optimization of a large number of parameters such as the viscosity and surface tension of probe solution, surface energy of nozzles, ejection frequency, actuation pressure and duration of jet system, and combating variable spot morphology caused by suboptimal fabrication parameters. [12][13][14][15] In addition, with the spread of microarray technology, there is increasing demand for the production of different specialized microarrays with a lower density of probes for use in ordinary laboratories. [16][17][18] Although all of the three above technologies are used to produce commercially available microarrays, there are few methods to economically and flexibly produce small batches of custom microarrays for prototyping experiments and specialized applications.…”