Non-contact production of oligonucleotide microarrays using the highly integrated TopSpot nanoliter dispenser

Abstract

For the first time we report on the production of oligonucleotide microarrays using a highly parallel and highly integrated, pressure driven TopSpot nanoliter dispenser. The system enables non-contact printing of different media like oligonucleotides, DNA or protein solutions. We optimized the printing buffer needed for oligonucleotides microarrays production with respect to two major aspects: microfluidical optimum for droplet dispensing and biochemical coupling efficiency on different commercially available microarray slides. Coefficient of variations (CVs) of generated spot diameters were measured to be smaller than 1% within one single dispensing nozzle and smaller than 1.5% within all 24 parallel nozzles of the printhead for all printing buffers used. No carry-over and no cross-talk was found, in extensive experiments with oligonucleotides. Optimized printing buffer compositions and concentrations for oligonucleotide microarrays were found, as well as optimized coupling protocols. Furthermore, buffers and protocols were adapted to a host of different microarray slides used. With this system, prime critical points of microarray production are solved, leading to high quality high throughput microarray fabrication.

Development and characterization of a disposable plastic microarray printhead

“…The results shown in Fig. 4(b) indicate that the spot volume of 1.9 nl±0.3 nl produced with the new printheads is indeed within the same range as that obtained using silicone-based printheads (Gutmann et al 2004). Evidently, the spotted liquid also affects the spot volume through its surface tension and viscosity.…”

Fabrication of high quality microarrays

“…The pins are attached to a robotic arm that moves the pins between the different probe solutions, the glass slides where the microarray is created and a washing station. Noncontact printing is similar in terms of robotics but instead of pins, small dispensing systems are mounted on the robotic arm [23,24]. The dispensing system can be based on inkjet, bubblejet or piezo actuation technology and can usually dispense in the range of 100 pL to 2 mL.…”

Highly sensitive polysilicon wire sensor for DNA detection using silica nanoparticles/γ-APTES nanocomposite for surface modification

“…Currently, the label-dependent DNA chip is one of the most popular analysis tools in the biological research because it can provide gene expression profiling of changes with chemical treatments, disease states, phenotypic differences, and mutations [1][2][3]. However, the DNA chip suffers from its slow transport mechanism in mixing the tested solutions because the solutions dispensed by pins are in the range of several hundred pico-liters to several microliters [4][5][6][7][8]. Although miniaturizing the sensor would reduce the number of droplets delivered and improve the solution mixing rate, there is a drawback to fluorescence-labeled methods in that a high-resolution optical detection system is needed to detect ultra-small spots on the chip.…”