Marksman Cellject device automates zebrafish injection for drug screening

The discovery is laid out in an article in today published online today in the journal PLoS ONE​, and has led to the spin-out of a new biotech called Marksman Cellject, in order to exploit the technique. The tool is currently limited to injecting zebrafish embyos, a widely used tool in the life sciences and high-speed injection is important for screening genes in genetics and drug molecules in drug discovery. Professor Yu Sun - who heads up the research group at the University of Toronto, Canada - believes automating the process could overcome "the problems inherent in manual operation, such as human fatigue and large variations in success rates due to poor reproducibility."​ This could facilitate large-scale molecule screening and determining gene function. The micro-robotic system is based on computer vision and motion control and is capable of immobilising a large number of zebrafish embryos into a regular pattern within seconds and injecting 15 embryos (chorion unremoved) per minute. According to Prof. Yu Sun, the success rate, survival rate and phenotypic rate are all close to 100 per cent. Several other techniques can be used to introduce molecules into cells, including electroporation, viral vectors, gene gun, ultrasonics and MEMS-based injection, according to the article. However, the scientists believe microinjection is still the most effective, taking into account cell damage, viability, and waste. It is also more effective at delivering large molecules, is more specific and the process doesn't affect the sample itself. The whole process can be followed live on an image display area and system information window and can be paused, if needed. The embryo immobilisation is achieved by using a vacuum pump to suck an individual embryo through numerous tiny holes in the device - each one is just a few millimetres across. Once trapped, the cells can then be automatically injected. Extra, non-trapped, embryos can be flushed away. One of Marksman Cellject's top priorities is to extend the tool to include other cell types, including mouse and human oocytes/embryos and adherent cells. Indeed, away from drug discovery, it is currently collaborating with the Toronto Centre for Advanced Reproductive Technology, a fertility clinic, to use the tool for in-vitro fertilisation applications.