John Gutierrez, a senior biochemistry major at Fresno State, delivered a captivating presentation on Oct. 6 entitled “Magnifying the Truth: A Look Into TEM and SEM in Forensic Science.”

Transmission Electron Microscopes (TEM) and Scanning Electron Microscopes (SEM) are advanced imaging tools used in scientific research, including materials science and biology.

Gutierrez said every detail matters in solving crimes, from macroscopic shoe mark impressions to microscopic pollen grains and skin cells. 

He said the scientific method plays a pivotal role in this process, and the field has seen significant advancements in analytical techniques and tools over the years.

One such breakthrough is the application of electron microscopy, which has transformed how forensic experts scrutinize evidence. 

Gutierrez delved into the applications of electron microscopes TEM and SEM. He noted that these cutting-edge instruments offer invaluable insights into evidence analysis.

“Most importantly, believe in yourself and be proud as it is not easy presenting in front of everyone like that. This experience is here for us to develop as individuals, and to prepare us for our future, in whichever path we decide to go.” John Gutierrez, senior biochemistry major’s advise to future student presenters.

Gutierrez explained that TEM are like super-powered magnifying glasses for forensic scientists. They can zoom in close and show incredible detail, even with objects as thin as 200 nanometers. 

But using them requires “tedious” preparation.

On the other hand, SEM looks at objects’ external surfaces and can handle thicker samples than TEM. While they are less costly, they cannot zoom in as much as TEM. 

These microscopes give forensic experts different ways to examine evidence, increasing the chances of solving crimes.

With poise and masterful delivery, Gutierrez engaged the audience, which included professors and students, and expertly fielded several questions, but admitted the experience was “nerve-wracking.” 

“Being on the spot and having to explain complex issues in front of faculty where you know everyone is watching what you say and how you respond to the questions was intimidating for me,” Gutierrez said. “It’s completely different from presenting in front of a regular class as these talks are comprised of faculty, graduate students, and other undergraduates or the public who might be interested.”

Among the attendees was Dr. Krish Krishnan, chair of the chemistry and biochemistry department and a key organizer of the Chemistry Seminar Series. 

Offering advice to future presenters, Gutierrez stressed the importance of thorough preparation and seeking feedback from friends, lab members, or peers. He encouraged students formulate questions in advance to address potential knowledge gaps and emphasized that it’s okay not to have all the answers. 

The seminar series continues next Friday with a presentation from Aaron Asparin and Aaron Chhun. 

Visit fresnostatecsm.com/event to see upcoming seminars.