Fujitsu's Biosciences Group this week launched a new version of its automated microinjection technology that will allow users to transfect adherent cells without having to first trypsinize them to release them from their growth surface.
The new platform, which Fujitsu says nearly doubles the transformation efficiency in difficult-to-transfect cell types, could allow Fujitsu to better compete with vendors such as Cellectricon and Cyntellect that have already developed alternative high-throughput transfection methods for such cells.
In addition, the new product could open the door for Fujitsu to the burgeoning market for human stem cells for drug discovery.
Ian Welsford, manager of application science in Fujitsu's Biosciences group, this week told CBA News that the product is a new version of the CellInjector platform Fujitsu launched in December, with modifications that make it more conducive for transfecting adherent cells.
The first version of CellInjector was capable of transfecting floating cells as well as adherent cells — but only after they had been trypsinized and released from a well plate. Such an approach is not desirable because naturally adherent cells may be less physiologically relative when floating in suspension, and once the cells are trypsinized, they cannot be reattached.
"It works for all kinds of adherent cells, but the particular interest that we've seen so far in the marketplace [is] from those researchers who are working with difficult-to-transfect cells such as human embryonic stem cells."
"This new version allows you to use the floating suspension mode to inject floating or suspension cells, or, for whatever reason, adherent cells that you wish to suspend," Welsford said. "But you can also use the unit in an adherent mode, where you can essentially keep the cells grown in their tissue culture dishes, and inject them right in the dish. That improves the efficiency for people working with these kinds of cells, because they don't have to do a whole lot of biochemical manipulation to them.
"The big advance is that you can leave them in your plate now, do not have to float them, can inject them in situ in the cell culture dish itself, and then do your analyses with minimal disturbance," he added.
To achieve this, Fujitsu made software and hardware modifications to the platform. The original platform contained a silicon chip with microscopic holes in it, through which suction was applied to draw in floating cells from suspension for microinjection. The new version contains an adaptor that allows researchers to simply use standard tissue culture dishes in place of the silicon chip, if so desired.
"A lot of the controlling modification also involves software and targeting control of the capillary," Welsford said. "So the adherent mode is operator-assisted, which means the operator needs to be involved in the direction of the capillary, but the system is still dramatically more rapid, because the position of the capillary is software-controlled on a computer screen rather than manually controlled under a microscope lens."
Fujitsu claims that the new method nearly doubles the transformation efficiency of difficult-to-transfect cell types over traditional methods such as Invitrogen's Lipofectamine reagent and Amaxa's Nucleofector electroporation device and associated reagents.
Welsford said that the average efficiency of those techniques is about 25 percent, and Fujitsu's running average using the murine erythroleukemia cell line K562 is around 49 to 50 percent. "As with any system, it's not perfect," he said. "There are always going to be some that don't transform."
Fujitsu's data supporting these claims is published in a white paper available on the company's website, but the data has yet to be published in a peer-reviewed journal or presented at a conference.
Such data will go a long way toward establishing Fujitsu in the increasingly competitive market for alternative transfection techniques. Automated, large-scale, and efficient transfection methods are crucial to avoid bottlenecking in high-throughput cell-based drug discovery (as well as other applications), and some vendors have beaten Fujitsu to the punch for adherent cells.
One example is Cyntellect, which markets the LEAP platform. This instrument uses automated imaging and lasers to selectively transfect adherent or suspension cells and to eliminate unwanted cells (see CBA News, 4/5/2005). It is unclear whether this platform is taking hold in drug-discovery applications, but Cyntellect has been marketing the tool since 2004, has won several NIH grants for various applications, and has published favorable data from multiple experiments.
Another competitor is Cellectricon, which launched CellAxess, its platform for automated, high-throughput electroporation-based transfection in December. Cellectricon also said that the platform can be used on both adherent and non-adherent cells (see CBA News, 4/21/2006).
Developing an efficient high-throughput transfection method for adherent cells is becoming even more important of late because of the increasing popularity of using human embryonic and adult stem cells in cell-based drug discovery.
"It works for all kinds of adherent cells, but the particular interest that we've seen so far in the marketplace [is] from those researchers who are working with difficult-to-transfect cells such as human embryonic stem cells," Welsford said.
Fujitsu said that is also has additional case data from customer collaborations on mouse model experiments using progenitor and some leukemic cells, but that it is not yet allowed to disclose that data due to customer confidentiality agreements. Welsford said he thinks the company will be able to disclose some specific examples of increased efficiency with these kinds of cells within the next couple of months.
Currently, the only CellInjector customer that Fujitsu has disclosed is the Whitehead Institute, which is using the technology for high-throughput cell-based studies such as peptide expression and trafficking in stem cells, assessment of gene expression controls, and the study of cell-signaling cascades (see CBA News, 12/19/2005).
Welsford said that Fujitsu expects to disclose the new customers soon.
— Ben Butkus ([email protected])