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High Throughput Microarray Printer constructed by the bioinstrumentation group at the Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA, USA
Background:
The development of microarrays for high throughput analysis biological samples has been one of the major scientific developments over the past decade. These arrays are now used for the highly parallel analysis for various genomic DNA-based assays, gene expression at the mRNA and protein levels. One of the very critical parts of array experiments is availability of arrays that are produced with high quality and adequate array printer is essential in this respect.
A large number of microarray printers have been built and many are commercially available. However, all these printers have significant limitations and do not allow manufacture of arrays that take full advantage of the potential of the technique. Commercial printers typically use metal pins with small slots to print the arrays. The pins are inefficient in their use of printing solutions, and the arrays that can be printed are limited in the density of the spots on the array. If arrays could be printed more compactly and if printing consumed a smaller amount of precious reagents, then the biological utility of the arrays would be considerably enhanced. In addition, the spot quality printed by those commercial instruments is usually not acceptable and not suitable for potential diagnostic applications.
High Throughput Microarray Printer:
The Bio-instrumentation Group at LBNL (Jian Jin, Robert Nordmeyer, Earl Cornell), in collaboration with the scientists at the UCSF (Daniel Pinkel et al.), including further modifications of hardware and software introduced by Jan Dumanski and Carl Bruder, has developed a printing system that addresses these limitations. It is unique in two ways:
1. The system uses capillary tubes as printing pins. These pins allow printing from 1536-well plates and also produce many more spots from the same amount of printing liquid as compared to the standard printing systems, which considerably reduces the cost of the arrays;
2. To further improve the printing quality, it is necessary to use latest state-of-the-art high-speed precision x-y stages and its electronics controlling system to overcome the problems associated with over-shooting and jittering, which have become more significant as high speed and density are required.
The above two features allow to reliably make small spots, so that the arrays can be printed at high-density (down to below 100 micrometer center-to-center distance between two neighboring spots, depending on the surface chemistry used for printing).
The printer shown on the pictures and film attached below is state-of-the-art machine, which is one three best units available world-wide. This printer is fully operative at High Throughput Microarray Printing Facility in Heflin Center for Human Genetics, University of Alabama at Birmingham (UAB) and is being used for a variety of projects in medical research and diagnostics, the largest project being production of 32K BAC human genome arrays.
The printer is located in an ISO class 5 clean room, which is fully compatible with leading industrial micro array printing facilities. Control of particles, temperature and humidity are essential prerequisites for printing high-quality micro arrays.
Basic technical specifications:
| Total capacity of slides to print on: 288 (3 plates x 96 standard size slides) |
| Number of pins which can be used for printing: 1 - 64 |
| Printing plates that can be used to print from: 96 well, 384 well, 1536 well |
Max. speed of printing head movement:
X axis; Y axis 1.50 m/s; 0.5 m/s
Acceleration X axis; Y axis: 12 m/s2 (=0-100 km/h in ~2.5 sec); 6 m/s2 |
| Overall Printer Precision: Prints spots with repeatability of equal or less 5μm (whether reprinting or from slide to slide, applying maximum speed) |
4 Motors:
X Linear stepper 1μm encoder
Y 2 x Linear stepper 1μm encoder
Z Linear stepper 1μm encoder |
| All components of the printer within the environmental chamber are capable of withstanding germicidal UV @ 254nm |
ROBOT FILM 
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