“Padilla came to the CiPD training program earlier this year with a Ph.D. in Chemistry from the University of Wisconsin-Madison. He is currently a postdoctoral fellow in the lab of Dr. Michael J. Mitchell of Penn’s Department of Bioengineering, where his research focuses on developing new materials to enhance the efficacy and safety of biological therapeutics. While passionate about research, he also has a strong interest in developing mentoring relationships and in teaching. At Wisconsin, Marshall earned a certificate in research, teaching, and learning, in which he conducted a research project on developing positive metacognitive practices in introductory organic chemistry. Additionally, he taught a course on mentoring in a research setting, and is passionate about promoting diversity and inclusiveness in biomedical sciences.”
A cross-kingdom partnership between bacteria and fungi can result in the two joining to form a “superorganism” with unusual strength and resilience. It may sound like the stuff of science fiction, but these microbial groupings are very much part of the here and now.
Found in the saliva of toddlers with severe childhood tooth decay, these assemblages can effectively colonize teeth. They were stickier, more resistant to antimicrobials, and more difficult to remove from teeth than either the bacteria or the fungi alone, according to the research team, led by University of PennsylvaniaSchool of Dental Medicine scientists.
What’s more, the assemblages unexpectedly sprout “limbs” that propel them to “walk” and “leap” to quickly spread on the tooth surface, despite each microbe on its own being non-motile, the team reported in the journal Proceedings of the National Academy of Sciences.
“This started with a very simple, almost accidental discovery, while looking at saliva samples from toddlers who develop aggressive tooth decay,” says Hyun (Michel) Koo, a professor at Penn Dental Medicine and a co-corresponding author on the paper. “Looking under the microscope, we noticed the bacteria and fungi forming these assemblages and developing motions we never thought they would possess: a ‘walking-like’ and ‘leaping-like’ mobility. They have a lot of what we call ‘emergent functions’ that bring new benefits to this assemblage that they could not achieve on their own. It’s almost like a new organism—a superorganism—with new functions.”
Hyun (Michel) Koo is a professor in the Department of Orthodontics and the divisions of Community Oral Health and Pediatric Dentistry in the School of Dental Medicine, co-founder of the Center for Innovation & Precision Dentistry (CiPD) at the University of Pennsylvania, and member of the Penn Bioengineering Graduate Group.
Controlled and actuated by magnetic fields, these mircrorobots are capable of precisely targeting the apical region — the opening where blood vessels and nerve enter the tooth — in a root canal.
With its irregularities and anatomical complexities, the root canal system is one of the most clinically challenging spaces in the oral cavity. As a result, biofilm not fully cleared from the nooks and crannies of the canals remains a leading cause of treatment failure and persistent endodontic infections, and there are limited means to diagnose or assess the efficacy of disinfection. One day, clinicians may have a new tool to overcome these challenges in the form of microrobots.
In a proof-of-concept study, researchers from Penn Dental Medicine and its Center for Innovation & Precision Dentistry (CiPD), have shown that microrobots can access the difficult to reach surfaces of the root canal with controlled precision, treating and disrupting biofilms and even retrieving samples for diagnostics, enabling a more personalized treatment plan. The Penn team shared their findings on the use of two different microrobotic platforms for endodontic therapy in the August issue of the Journal of Dental Research;the work was selected for the issue’s cover.
“The technology could enable multimodal functionalities to achieve controlled, precision targeting of biofilms in hard-to-reach spaces, obtain microbiological samples, and perform targeted drug delivery, ” says Dr. Alaa Babeer, lead author of the study and a Penn Dental Medicine Doctor of Science in Dentistry (DScD) and endodontics graduate, who is now within the lab of Dr. Michel Koo, co-director of the CiPD .
In both platforms, the building blocks for the microrobots are iron oxide nanoparticles (NPs) that have both catalytic and magnetic activity and have been FDA approved for other uses. In the first platform, a magnetic field is used to concentrate the NPs in aggregated microswarms and magnetically control them to the apical area of the tooth to disrupt and retrieve biofilms through a catalytic reaction. The second platform uses 3D printing to create miniaturized helix-shaped robots embedded with iron oxide NPs. These helicoids are guided by magnetic fields to move within the root canal, transporting bioactives or drugs that can be released on site.
“This technology offers the potential to advance clinical care on a variety of levels,” says Dr. Koo, co-corresponding author of the study with Dr. Edward Steager, a senior research investigator in Penn’s School of Engineering and Applied Science. “One important aspect is the ability to have diagnostic as well as therapeutic applications. In the microswarm platform, we can not only remove the biofilm, but also retrieve it, enabling us identify what microorganisms caused the infection. In addition, the ability to conform to the narrow and difficult-to-reach spaces within the root canal allows for a more effective disinfection in comparison to the files and instrumentation techniques presently used.”
Michel Koo is a professor in the Department of Orthodontics and divisions of Community Oral Health and Pediatric Dentistry in Penn Dental Medicine and co-director of the Center for Innovation & Precision Dentistry. He is a member of the Penn Bioengineering Graduate Group.
The inaugural class of the CiPD NIDCR T90/R90 Postdoctoral Training Program Fellows with Dean Mark Wolff (center); Dr. Michel Koo, Founding Director of CiPD (far right); and CiPD Co-Director Dr. Kathleen Stebe of Penn’s School of Engineering and Applied Science (far left).
With one of its key missions to develop a new generation of scientists at the interface of dental medicine and engineering, the Center for Innovation & Precision Dentistry (CiPD) has selected its inaugural class of fellows for its new postdoctoral training program.
The CiPD was awarded a $2.5 million T90/R90 grant from the National Institute of Dental and Craniofacial Research (NIDCR) last summer to establish the program, recently naming this first cohort of fellows that includes Justin Burrell, Marshall Padilla, Zhi Ren, and Dennis Sourvanos.
“We’re hoping this program will promote cross-pollination and create a culture between these two fields to help dentists develop innovative strategies with engineers,” says Penn Dental Medicine’s Michel Koo, Co-Director of CiPD, who launched the Center in 2021 with Co-Director Kathleen Stebe, Richer & Elizabeth Goodwin Professor in Penn Engineering’s Department of Chemical and Biomolecular Engineering. “Dentists can learn from engineering principles and tools, and engineers can understand more about the needs of the dental and craniofacial fields. We’re providing a platform for them to work together to address unmet clinical needs and develop careers in that interface.”
The NIDCR T90/R90 Postdoctoral Training Program aims to specifically focus on the oral microbiome, host immunity, and tissue regeneration, each of which ties into different aspects of oral health, from tooth decay and periodontal disease to the needs of head and neck cancer patients. To advance these areas, emerging approaches, from advanced materials, robotics, and artificial intelligence to tissue engineering, chloroplast- and nanoparticle-based technologies, will be leveraged.
As part of the two-year training, each postdoc will receive co-mentorship from faculty from each school in conjunction with a career development committee of clinicians, basic scientists, as well as engineers. These mentorships will be focused on research outcomes and readying participants to submit grants and compete for positions in academia or industry.
The inaugural class of fellows includes Justin Burrell, a postdoctoral student in the lab of D. Kacy Cullen, Associate Professor of Neurosurgery; Marshall Padilla, a postdoc in the lab of Michael J. Mitchell, Skirkanich Assistant Professor of Innovation in Bioengineering; and Zhi Ren, a postdoc in the lab of Michael Koo; and Dennis Sourvanos, an Advanced Graduate Dental Education resident at Penn Dental Medicine whose research has been co-directed by Timothy C. Zhu, Professor of Radiation Oncology in the Perelman School of Medicine. Cullen, Mitchell, Koo and Zhu are all members of the Penn Bioengineering Graduate Group.
In a proof-of-concept study, researchers from the School of Dental Medicine and School of Engineering and Applied Science shows that a hands-free system could effectively automate the treatment and removal of tooth-decay-causing bacteria and dental plaque. (Illustration: Melissa Pappas)
A shapeshifting robotic microswarm may one day act as a toothbrush, rinse, and dental floss in one.
The technology, developed by a multidisciplinary team at the University of Pennsylvania, is poised to offer a new and automated way to perform the mundane but critical daily tasks of brushing and flossing. It’s a system that could be particularly valuable for those who lack the manual dexterity to clean their teeth effectively themselves.
The building blocks of these microrobots are iron oxide nanoparticles that have both catalytic and magnetic activity. Using a magnetic field, researchers could direct their motion and configuration to form either bristlelike structures that sweep away dental plaque from the broad surfaces of teeth, or elongated strings that can slip between teeth like a length of floss. In both instances, a catalytic reaction drives the nanoparticles to produce antimicrobials that kill harmful oral bacteria on site.
Experiments using this system on mock and real human teeth showed that the robotic assemblies can conform to a variety of shapes to nearly eliminate the sticky biofilms that lead to cavities and gum disease. The Penn team shared their findings establishing a proof-of-concept for the robotic system in the journal ACS Nano.
“Routine oral care is cumbersome and can pose challenges for many people, especially those who have hard time cleaning their teeth” says Hyun (Michel) Koo, a professor in the Department of Orthodontics and divisions of Community Oral Health and Pediatric Dentistry in Penn’s School of Dental Medicine and co-corresponding author on the study. “You have to brush your teeth, then floss your teeth, then rinse your mouth; it’s a manual, multistep process. The big innovation here is that the robotics system can do all three in a single, hands-free, automated way.”
Hyun (Michel) Koo is a professor in the Department of Orthodontics and divisions of Community Oral Health and Pediatric Dentistry in the School of Dental Medicine, co-director of the Center for Innovation & Precision Dentistry, and member of the Penn Bioengineering Graduate Group at the University of Pennsylvania.
Edward Steager is a senior research investigator in Penn’s School of Engineering and Applied Science.
Koo and Steager’s coauthors on the paper are Penn Dental Medicine’s Min Jun Oh, Alaa Babeer, Yuan Liu, and Zhi Ren and Penn Engineering’s Jingyu Wu, David A. Issadore, Kathleen J. Stebe, and Daeyeon Lee.
This work was supported in part by the National Institute for Dental and Craniofacial Research (grants DE025848 and DE029985), Procter & Gamble, and the Postdoctoral Research Program of Sungkyunkwan University.
