“My only advice? Experience as much as you can, so you don’t have any regrets later on”

Mazzarine – enrolled in the Master’s program in chemistry (Chemistry & Life Sciences) offered by Chimie Paris Tech-PSL, Ecole Normale Supérieure-PSL and ESPCI Paris-PSL – is currently doing an internship at Johnson & Johnson Laboratories. She tells us about her university experience and explains how she discovered the path she wanted to follow.


Mazzarine has always had a passion for biology and chemistry. After getting her baccalauréat in science in Dakar, Senegal, she pursued a double international Bachelor’s degree in biology and chemistry at Université Grenoble Alpes, then joined the chemistry Master’s program (Chemistry & Life Sciences) at PSL.
“I wanted to enroll in a chemistry and biology Master’s degree program that included classes in English. When I was researching what was available, I found that there were only five interdisciplinary programs like that offered in France. One of those was the PSL Master’s program, which offered instruction in both academic  and industrial research and was taught entirely in English. So that was the one!”

During her studies, she met Gilles Gasser, a research professor at Chimie ParisTech-PSL who had founded the state-of-the-art Laboratory for Inorganic Chemical Biology in 2016. Mazzarine gained the opportunity to join that international team as part of her first-year internship.
“When I arrived in his laboratory, I didn’t know yet whether I wanted to specialize in chemistry or biology. Gilles let me combine them both. I worked in biology but I was next to a chemistry laboratory where he was devising new drugs. So that was how I learned how drugs are developed and I could understand their effects on the human body. There’s no point in producing a medicine and not knowing how it actually works in the body, or in testing a drug without knowing its chemical structure. It’s essential to have both disciplines – they complement each other. Even though I was working in biology, I had a much better understanding of what I was doing.”

On a quest to gain new skills and attracted to innovative projects, Mazzarine chose to join PSL’s iTeams program for Master’s, PhD and post-doctoral students with a special interest in innovation and entrepreneurship.
 “I had the opportunity to work at The Twinkle Factory, a start-up founded by Arnaud Gautier, Ludovic Jullien and Franck Perez, which uses novel methods to develop fluorescent sensors. Our team consisted of five students from a variety of PSL schools  (IBPC, EPHE-PSL, ESPCI Paris and Collège de France). Those different backgrounds are what made us a formidable team. I really enjoyed working in a group with students I didn’t know. It’s by talking with them and asking questions that you gain experience.”
Mazzarine loves to learn from others, but she also loves to pass on what she knows. That was something she did at the PSL Welcome Desk, the office that helps international students get their bearings at PSL.
“Each person’s experience is different. I enjoy helping international students make decisions and giving them the tools they need to succeed. But I also tell them that you need to experience things before you decide it’s not something you want to do. There are some things you can’t just read about – you have to experience them.”

It was after completing her post-Bachelor’s internship at the French Alternative Energies and Atomic Energy Commission (CEA) in Grenoble that Mazzarine decided on a career plan.
“I wanted to do an internship in fundamental research to see if I would enjoy it. You had to be extremely fussy and the experiments required a lot of patience. Sometimes you don’t get any results for years and years. It was a very rewarding experience because I acquired new skills! But I realized that it didn’t suit me and I needed something more applied.”

In her proactive search for a career path, Mazzarine turned her eye to industrial research, and today she’s doing an internship at the Johnson & Johnson pharmaceutical laboratories, where she’s working on skin models used to test the efficacy of drugs in the pre-clinical phase.
“Before a drug is put on the market, extensive pre-clinical testing is conducted on cell models and then on mice. The models we reproduce aren’t an adequate match for cells in mice or the human body, so researchers are forced to conduct a lot of testing on animals prior to clinical testing. My job is to work on skin models so as to reproduce cells that are closer to human cells. That will improve pre-clinical testing.”

Mazzarine would like to pursue a doctorate and do her doctoral dissertation on clinical and pre-clinical testing.
“It’s taken me a few years to bring my career plan to maturity.  But after having learned about and tried out many different things, some of which I regretted, I managed to find what suits me best. Ultimately we learn a lot from our mistakes and the decisions we’ve made, and that’s how we succeed in building a solid future.”