Dr. Steven Wrenn’s parents grew up on tobacco farms in North Carolina. Each parent left the farm to attend college, and each enjoyed a career as an educator (his mom as an elementary school teacher and his dad as a university professor). Dr. Wrenn's interest in academia likely stems from his parents' vocation, and his interest in chemical engineering can be traced to the times he visited and worked on the tobacco farms (which continued to be operated by relatives) where his parents were raised. Young Steven became fascinated by the farming process, from planting seeds to pulling leaves. He began to wonder how non-farmed products (that is, household items such as appliances and calculators, or, in today's world, cell phones, which - unlike tobacco - cannot be grown) are produced; what is taken out of the earth and how is it reformed to produce the goods that we use every day? While he excelled at math and chemistry in high school, many of his questions - including how natural materials are converted into products - would remained unanswered until he went to college.
As a freshman at Virginia Tech, Steve was inspired by two professors. The first was chemistry professor Jerry Glanville, who made a trip with Steve to the campus bookstore to buy for him two books: The Double Helix and The Curve of Binding Energy. The other was mathematics instructor Gail Laurent, who modelled that repetition is the mother of learning by insisting that her college students repeat after her, phrase by phrase, elementary school style, "An integral - is a Riemann sum - in the limit - as the norm of the partition - goes to zero." Dr. Wrenn occasionally repeats this exercise when chemical engineering upperclassmen reveal (or at least claim) that they don't understand integrals.
Dr. Wrenn enriched his college education with two co-op stints during his sophomore and junior years. Both co-ops were for GE Plastics (the first actually began with Borg Warner Chemicals, which was acquired by GE), located in Parkersburg, West Virginia. There he was able to see the raw materials-to-products process he had questioned as a boy: natural elements arrived via rail car at the chemical plant, where they were transformed by chemical reactions and separation equipment into plastic products used in cars, hair dryers, football helmets, and the like. The highlight of Dr. Wrenn's co-op was that he developed a new terpolymer comprising methylmethacrylate, alphamethylstyrene, and acrylonitrile, which he termed MAMSAN; he initially made gram-size batches in the lab and later scaled the process into a continuous operation.
After college, Dr. Wrenn worked as Process Engineer at ICI Americas, which later became Zeneca Inc., in New Castle, DE. A highlight of that job was that he scaled up a process for a specialty chemical used as a component in the production of a drug for the treatment of osteoporosis and bone cancer. He scaled up a process from half-liter batches to 5000-gallon batches and was part of the start-up team when the process went into production at a facility in Mt. Pleasant, Tennessee (near Nashville).
Later, while still working as a process engineer for Zeneca, Steve read The Making of the Atomic Bomb. He was excited both by the lives of scientists described in the largely bibliographical opening chapters and by the stories of the discoveries of sub-atomic particles that led to our present-day understanding of atoms and molecules. This book was the impetus for Wrenn's application to graduate school.
Wrenn earned his PhD at the University of Delaware under the guidance of Dr. Eric Kaler (now President of The University of Minnesota). Wrenn’s graduate research was on biologically-based colloids. The basic question to be answered was why certain people develop gallstones; thermodynamics suggests that all people should develop gallstones, but the issue is in fact a question of kinetics. Specifically, what is the rate at which cholesterol nucleates from a biliary, phospholipid vesicle to produce microscopic crystals that later become stones? As part of his doctoral thesis work, Wrenn developed a fluorescence assay that allows one to pin-point the onset (and measure the rate) of cholesterol nucleation.
Dr. Wrenn accepted a position with CBE at Drexel in 1999. After several years, Wrenn met Dr. Peter Lewin from the School of Biomedical Engineering at the Drexel gym. They talked about ultrasound and colloids, and Lewin suggested that Wrenn should visit the IPPT PAN (Institute of Fundamental Technological Research at the Polish Academy of Sciences) in Warsaw. As a result of that visit, Wrenn met a German professor of Electrical Engineering, Georg Schmitz, who studied ultrasound signals produced by microbubbles that serve as contrast agents. Schmitz nominated Dr. Wrenn for an Alexander Von Humboldt Fellowship, which he received and used to support his yearlong (mid 2006 - 2007) sabbatical at Ruhr University in Bochum, Germany in Schmitz ’s lab.
Wrenn and Schmitz are among a small number of researchers pioneering a field, called theranostics. This involves interactions of ultrasound with colloidal particles and microbubbles for both therapy and diagnostics. Therapeutic applications include wound healing and controlled drug delivery (using ultrasound as the release mechanism), and diagnostic applications are the familiar imaging but with enhanced contrast and the ability to detect blood flow.
Dr. Wrenn runs regularly in Ridley Creek State Park and Fairmount Park and swims regularly at the DAC. He enjoys reading classic literature (and will occasionally write a summary in the form of a rap). Dr. Wrenn lives in Swarthmore, PA, with his wife, Lisa, and his children, Claudia and Luca. His oldest son, Nicholas, is an undergraduate student at Drexel University.