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November 2013 Laboratory Focus www.laboratoryfocus.ca
FEATURE Figure 3
Media fill module for media exchange.
and software stability. In addition, labs should consider how cells are kept in suspension to pipette them for plating, passaging and harvesting, how to handle large volumes of media for media exchanges, and how to transfer adherent cells from one vessel to another. Hamilton’s liquid handling Microlab® STAR robots are perfectly suited for handling the demands of automated cell culture. Pipetting Also critical in transitioning to an automated system is the use of high-performance pipetting air displacement technology used in electronic handheld pipettes with sterile disposable tips. This technology eliminates the need for system liquids and self-contained liquid channels, reducing the contamination risk associated with backfilled liquid pipetting technologies that employ multiple tubes, pumps, valves, and connection fittings. The technology is beneficial when working with sterile cell cultures and helps to eliminate demanding and costly decontamination routines. Hamilton Robotics has an air displacement pipetting technology that also enables a broad dynamic pipetting range of 0.5 µL to 1 mL or 200 µL to 5 mL within the same pipetting channels. This large dynamic fluid range allows users to handle larger volumes of cells and maintain them in larger vessels, and enables easier media exchange. Pipetting channels use Compressed O-Ring Expansion (CO-RE™) technology, central to Hamilton Robotics’ air displacement pipetting platforms. This technology enables pipette tips to attach and detach with minimum pressure and uses a lock-and-key mechanism for tip attachment [Figure 2]. It also enables reproducible pickup of tips and tools and provides superior positional precision of +0.1 mm in all axes. The CORE attachment of tips provides gentle tip ejection, eliminating splashing and production of aerosols further reducing potential contamination. CO-RE technology provides a universal tool for accessing CO-RE grippers that can
Figure 4
Hamilton Heater Shaker for heating and assisted adherent cell passaging.
move deck labware, ensure sterile manipulation of culture vessel lids, and enable chamber slide lid handling. Hamilton Robotics accessories for cell culture processing Plating cells – Researchers often must start their cell culture experiment with a large number of assay-ready cell plates or batches of cells that originate from a single, large suspension. Hamilton Robotics provides users with a way to maintain a continual suspension of a large volume of cells for longer runs of cell-plating experiments during which cells can often settle. With Hamilton’s Suspension Module, cells are kept in suspension with a disposable, sterile polypropylene suspension trough and are magnetically driven with stainless steel paddles. This tool enables the liquid handling robot to continually access cell suspensions without extra pipette mixing steps, saving time and improving cell viability. Media exchange – Automated cell culture systems require large volumes of fresh media from a sterile source container to be delivered to the pipetting platform when performing media exchanges. To meet this need, Hamilton Robotics offers a Media Fill Module [Figure 3] that allows the delivery of media or other reagents from source containers stored in a 4° C refrigerator that may be placed on a shelf beneath the pipettor. When called for in a method, media for exchange is pumped from the refrigerator through a heating coil that pre-warms the media to 37° C before delivering it to a reagent trough on the deck of the pipettor. The Media Fill Module is compatible with commonly used media bags and containers, has sensors for automated volume control, provides a sterile, disposable fluid path, and is compatible with the 1 mL and 5 mL independent channels as well as 96 and 384 multi-probe heads (MPH). Passaging and harvesting cells – Both suspension and adherent cells can be grown on an automated cell culture system. As their name im-
Figure 5
plies, suspension cells are grown in suspension and do not need to attach to a surface. Therefore, automated manipulation of these cells is considerably simpler than passaging and harvesting adherent cell lines, which require a surface such as plastic, basement membranes, or microcarriers to grow and thrive. In addition, for adherent cells to be passaged, they must be dissociated from the culture vessel in which they adhere. Hamilton offers several solutions for manipulating and passaging both adherent and suspension cell cultures. • Multiflex Tilt Module – Hamilton offers a Multiflex Tilt Module, which is an on-deck accessory enabling more efficient removal of media, wash buffers (i.e., PBS), dissociation reagent, and cell suspension from culture vessels when performing common tasks such as passaging or harvesting. The tilt module, which is compatible with all SBS format labware (e.g., Omni 6- to 96-well plates), tilts at various angles for maximum reagent and cell removal, thus allowing users to reduce dead volume and residual reagent left over after volume transfers. • Heater Shaker – To assist with dissociation of adherent cells from a culture vessel while maintaining viability, Hamilton offers a heated assistance device called the Hamilton Heater Shaker II (HHS II) [Figure 4]. The HHS II maintains reagents and cells at user-defined temperatures during processing steps that take place on deck of the liquid handler. The shaking feature can help to dissociate difficult-to-detach adherent cell lines for passaging and harvesting when incubated with a dissociating reagent. Keeping the cells on deck saves valuable time compared to transporting plates to and from an incubator. The HHS II offers a heating range of ambient +5° C to 105° C and is capable of shaking in clockwise or counter-clockwise motions with multiple amplitude settings. • Data software – Hamilton’s VENUS Software enables any workflow in
Stem Cell Maintenance Model System
cell culture to be automated on one instrument. Key features include: native data and file handling, a stable run-time environment with numerous error handling options to ensure protocol run completion, the ability to create easy-to-use protocols, and unmatched customization capabilities. Hamilton’s VENUS Dynamic Scheduling software allows for the automation of more complex cell-based assays. The VENUS suite of software products provides the flexibility and control of your cell culture processes.
Containment devices Sterile containment is a key factor to consider in cell culture automation and often presents one of the biggest hurdles. For cells to grow in culture without being affected or overtaken, they must be protected from the external environment, harmful microbes, and contaminating agents such as bacteria, yeast, fungi, and mycoplasma. Some cells grown in culture may also need to be isolated from the user to provide protection from harmful byproducts of the culture or reagents, such as viral DNA. • HEPA filtered hoods – When planning for an automated cell culture system, one of the most important items to consider is maintaining the sterility of cell plates when they are removed from the incubator. Cells are most vulnerable to contamination when being transported to a cytometer for a confluence read or to a liquid handler for a media exchange. Hamilton offers a HEPA filtered hood that interfaces directly with its liquid handling platforms to provide an enclosed, contamination-free, clean air zone and workspace within the pipetting environment. The Hamilton hood incorporates a Class II-certified HEPA filter (and pre-filter) with a UV germicidal light option. • Biosafety cabinets – Hamilton liquid handling platforms are easily installed within biosafety cabinets readily available on the market. Biosafety cabinets offer great perfor-
