President’s Message/Message du Président 20 Spring / Printemps 2018 DNA MICRO-ARRAYER DNA array is a generic name covering different molecular biology products and techniques. It can be described as a manifold of DNA fragments (spots) of oligonucleotides at low, medium or high density. DNA arrays are used as research and diagnostic tools. The array of DNA fragments on a solid surface allows detection of the expression of thousands of genes in a single experiment. Gene array technology is becoming one of the most common techniques used in all molecular biology laboratories. The advantages of DNA array tech- nology are: simultaneous analysis of many genes in a single experiment; quantitative and reproducible results; speeding up basic biological research and disease diagnosis; reduction of time, cost, and risks associated with discovery and development. In terms of the technology used to make DNA arrays, there are three methods: (i) photolithography method that is based on-site oligonucleo- tide synthesis; (ii) micro-spotting with quill pins; and (iii) ink jetting. The spotting tools are: split/quill pins, solid pins, piezoelectric pins, capillary, ring-and-pin systems. The support used for DNA arrays can be: nylon membrane, polypropylene membrane, or glass slides. The meth- ods of DNA binding to the support are based on electrostatic and hydro- phobic interactions with covalent links. For detection of gene expres- sion, complementary DNA (cDNA) is spotted first onto the slides, then the target DNA is hybridized with the cDNA, and the expression is identi- fied through probe labeling: radio- activity (33P) and fluorescence (CY 3 and CY 5), and subsequent detection (reading of color intensity). Robot spotters have been developed for DNA spotting on glass slides. A spotter has a large spotting surface (75 or 126 slides), modular & reconfig- urable structure, able to spot up to 83,000 spots per 25 mm x 75 mm slide, and capable of performing other bio-laboratory tasks such as arraying, gridding, re-arraying, and pipetting. The robot system is based on a high quality three axis gantry robot, with 1.25 µm resolution of motion along each axis, and impedance control to avoid high impact forces at the con- tact between the slide and the pin. The system has a repeatability of 2.50 µm, and high bandwidth communica- tion with the controller. There is no heating, vibration, and the speed is 1 spot/slide/pin (61,000 genes are spot- ted in 3.5 h). The slides can be of 25 x 75 mm, 25 x 25 mm, or 50 x 75 mm. 1 to 8 micro-titter source plates and 1 to 6 small membrane holders can be used along with up to 126 slides. The cleaning of the pins between loads is done in a water bath that uses active water pump for cleaning. The robot is designed to collect DNA from 96-well and 384-well source plates. 1 to 48 pins can be used simul- taneously. Each pin collects 250 nl of solution and spots 0.6 nl per dot on 75 to 126 microscope glass slides. The center-to-center distance is 120 µm. A vacuum chamber is used to dry out excess material from the quill pins, and dry off the water after washing them. A blotting pad is used to elim- inate excess material from the pins before spotting. The quill pins have long life (1,000,000 spots). They gen- erate 75 or 90 µm diameter spots. Each pin can be replaced individual- ly, and up to 250 dots per sample/ one dip can be obtained. Environmental control is provided with a positive pressure HEPA Fun Filter and PPHC humidity controller (limits evap- oration and fast drying of the spots). The motion controller is based on an embedded PC-104/Pentium. A Graph- ical User Interface is used to program the spotter and monitor the execu- tion. The host computer is based on Pentium/Windows NT. The host con- troller module can be at a remote location. The Graphical User Interface is intuitive and Windows-based for easy control of number of slides, rows, columns, array pattern, dots per row or column, speed, spotting order, type and direction of source plate or membranes, number of pins, etc. Simple robotic language is used for programming the robot. DNA Microarrayer Manifold of up to 48 quill pins (Continued on page 22) ROBOTIC CELL SAMPLE PREPARA- TION OF LIQUID SCINTILLATION ANALYSIS Managing employees who work at nuclear power stations presents some unique challenges. One of the issues that requires close monitoring is employees’ exposure to radiation. Quick and accurate detection of any anomalous radiation exposure can improve the health and safety of the employees as well as the operational safety of the power station. One of the common methods of mon- itoring radiation exposure is per- forming a daily scintillation count of an employee’s urine sample. A precise amount of sample is mixed with a known chemical for analysis. This pro- cess is tedious and time consuming. Typically, the amount of sample is in the 1000 µl range and the cocktail is in the 8ml range. While these volumes are not unduly small, they are too small to dispense accurately into the vial without proper laboratory equip- ment. A turnkey robot system was developed for the bioassay sample preparation, handling and analysis. The robot takes a very small quantity of the sample from a container, puts it into a sample vial, adds reagents, caps and seals the vial, mixes it, and places it into a cas- sette for analysis. More than 500 samples per day can be processed. Processing laboratory vials Picking up samples from vials Biotechnology and Laboratory