Dr. Woo Young Lee of the Chemical Engineering and Materials Science department along with Dr. Hongjun Wang of Chemistry, Chemical Biology and Biomedical Engineering at Stevens Institute of Technology have recently received significant NSF funding for their research entitled, “Evaporative Assembly of Drug-Eluting Bioresorbable Nanocomposite Micropatterns.”

“This award is a reflection of the pioneering work being undertaken by Professors Lee, Wang, and their colleagues at Stevens in the area of infection-resistant orthopedic implants,” explains Dr. Michael Bruno, Dean of the Schaefer School of Engineering and Science. “We congratulate Professors Lee and Wang on this significant step in their ongoing efforts to contribute to a solution to this critical problem.”

Stevens infection-resistant orthopedic research explores the inkjet printing of drug-eluting, bioresorbable micropatterns onto the surface of orthopedic implants, as a novel means of preventing bacterial infection of the implants, also known as “biofilm formation.”

Despite the tremendous improvements in orthopedic implant procedures, hospital-acquired bacterial infection is the dominant cause of implant failure and causes significant patient trauma in addition to a healthcare burden of $3 billion annually to the U.S. economy each year.
Fighting implant infection is far more complex than simply getting a prescription for antibiotics. Bacteria that grow in biofilm communities can be as much as 10,000 times more resistant to antibiotics than the so-called planktonic bacteria, which circulate around the body as individual cells. Resolving an implant infection usually requires that the implant be entirely removed, the surrounding tissue cured of infection, and then a second prosthetic device is implanted. This can take months and many tens of thousands of dollars. Solving this problem requires a broad range of expertise from many different disciplines.

As such, Drs. Lee and Wang hope to usher in an entirely new paradigm of scientific understanding and research opportunities aimed at understanding the complex interplay among host tissues, bacteria and biomaterials.

This inkjet method is one of a series of new methodologies seeking to advance the study. Inkjet printing eliminates the opportunity for bacteria to form biofilms while promoting rapid strong bone formation on the implant surfaces. During inkjet printing, evaporative assembly mechanisms are used to create nanocomposite micropatterns which consist of calcium phosphate and antibiotic nanocrystals (~100 nm) dispersed in a biodegradable polymer matrix. Inks are formulated to tailor nanocomposite morphology for:

• steady antibiotic release as a mechanism of killing opportunistic bacteria that will come in contact with implant surfaces and thus preventing biofilm formation and
• optimization of the osteoconductive property of calcium phosphate nanocrystals for rapid and direct new bone formation.

Microfluidic co-culture tools are used to project the ability of micropatterns to prevent biofilm formation while enhancing the formation of 3D bone tissue-like structures on the titanium alloy surface. Results from this project are used to define the criteria for designing implant surfaces for optimum infection-prevention and wound-healing functions.

In addition to the research itself, this grant will be used to support the interdisciplinary training of one doctoral and twelve undergraduate students at Stevens, and will enhance the local biomedical device industry in Northern New Jersey which plays a key role in regional, national and global economies.

For more information about this research and other activities in health care at Stevens, please contact Dr. Peter Tolias.