Transfecting Zebrafish Scales with Plasmids Using Magnetofection

Hi! Please check out my video summarizing my project on transfecting zebrafish scales with plasmids using magnetofection!

Zebrafish scales are a very important tool for research, and there is significant scope for further research because they are so powerful. In my project last year, I discovered that scales from transgenic zebrafish express those transgenes because the cells are still alive, and they can respond. This project aims to look further into the scale and see if, after transfecting the scale with plasmids or engineered loops of DNA, the cells can actually express the encoded fluorescent proteins. Transfection is the process of artificially introducing nucleic acids into cells. This could lead to many real-world applications, such as helping with osteoarthritis research and providing a medium to cure breast cancer.

Magnetofection is a type of transfection that uses a magnetic field to pull the magnetic nanoparticles and nucleic acid complexes onto the target cell or tissue, but on a scale, in this case. The magnetic solution had positively charged iron particles in it, which attracted to the negatively charged DNA of our plasmid, creating a complex.

For the procedure, scales were plucked from an anesthetized zebrafish, and those scales were put into a petri dish with Dulbecco’s Modified Eagle Medium (DMEM), which is a culture medium. The transfection solution was prepared by adding XPmag and the plasmid to a microfuge tube containing DMEM, Fetal Calf Serum (FCS), and Penicillin-Streptomycin. The plasmids varied in these experiments because I wanted to see whether different parts of the cell could be transfected.

The scale was placed into another petri dish, with the excess culture medium removed by tapping the scale against the bottom of the dish. The scale was placed first, and then the transfection solution was added onto the scale. The petri dish was then placed on a neodymium magnet for 15 minutes, as instructed by the magnetofection kit.

The plasmids I used were pLifeact mScarlet, which targets the actin filaments in the cell, and memNeon, which targets the plasma membrane in the cell.

Another experiment I conducted was a double transfection, meaning that both the pLifeact mScarlet and memNeon plasmids were added to the XPmag to make the transfection solution.

The scales were then mounted on slides and used for confocal microscopy.

All of these experiments were done in a lab at the University of New Brunswick.

Lipofectamine, which is the most common transfection reagent, did not work, which is why I resorted to the magnetofection technique. The magnetofection worked for the 15-minute transfection, which was suggested by the magnetofection instructions. There was clear fluorescence underneath the confocal microscope. I could see the plasma membranes shining green in some cells, clearly indicating that the transfection worked and that the cells were able to express the encoded fluorescent protein of the plasmid.

Later, I conducted a double transfection experiment, where I used 2 different plasmids that targeted the actin filaments (shown in magenta) and the plasma membrane (shown in green). These experiments were successful, showing that the positively charged iron particles in the XPmag (transfection solution) were attracted to the negatively charged DNA, and that the magnet successfully brought the complex across the cell membrane. Also, these experiments were conducted in real time with live cells, allowing me to observe how the cells behave in their natural environment. The time-lapse videos show the cell's processes as well. This project unlocks so much more potential for what can happen with the scale.

The scale is such a powerful tool for research because it is an organ, not just a bunch of messed-up cells in a petri dish. The scale consists of multiple cell types, such as epithelial cells, osteoblasts, and osteoclasts. Conducting this magnetofection technique now allows us to observe the actual interactions and stigmergy between cells in the scale in their natural habitat because this transfection worked on multiple cell types, showcasing its power. Looking at conventional tissue culture cells is misleading because those cells are unnatural, as they are isolated, a singular cell type, and not in their natural habitat.

Scales are robust and strong, which makes sense given that they are external organs on the zebrafish. Scales can also be treated with drugs or treatments that would kill an embryo. Scales are really easy to image because they are relatively flat and can be kept alive in culture medium for 5 days, allowing them to be imaged for days at a time. This allows researchers to actually see the cell-to-cell interactions at high resolution in real time. All of these reasons show why the scale is such a powerful and diverse medium for research.

This project will help bone biology and bone research, and can potentially help with osteoarthritis, osteoporosis, and breast cancer.

The next step of this project is to xenograft metastatic tumour cells onto these zebrafish scales and see whether they invade them. If they do, then I can use drug treatments on it to see if I can stop this invasion, and that can directly correlate to breast cancer, as the tumour cells in breast cancer target the bone.

I would like to thank Dr. Bryan Crawford for his help and guidance on this project.

De Vrieze, E. (2014). Zebrafish scales in bone research [PhD dissertation, Radboud University Nijmegen]. https://doi.org/10.13140/2.1.3475.7443

OZ Biosciences & Boca Scientific. (2021). XPMag - Transfection Reagent Instruction Manual. In OZ Biosciences [Report]. Retrieved November 20, 2025, from https://www.ozbiosciences.com

ThermoFisher Scientific. (2006, July 11). Lipofectamine 2000. Retrieved February 15, 2026, from https://www.thermofisher.com/ca/en/home/references/protocols/cell-culture/transfection-protocol/lipofectamine-2000.html