SBES Distinguished Lecturer Series, March 4

March 4, 2014, 11-12:15, 310 Kelly (ICTAS) /WFU: Biotech Bldg./VTCRI: R2139

Biological Laser Printing (BioLP) of Microvascular Cells onto Composite Hydrogel Biopapers

Dr. Bradley Ringeisen,

Dr. Bradley Ringeisen

Head, Bioengry and Biofabrication,

U.S. Naval Research Laboratory

Defense Threat Reduction Agency (DTRA)

Science & Technology Manager

Diagnostics and Disease Surveillance Division


Two major challenges in tissue engineering are mimicking the native cell cell arrangements of tissues and maintaining viability of threedimension (3D) tissues thicker than 200μm. Cell printing and prevascularization of engineered tissues are promising approaches to meeting these challenges. We suggest that both challenges could be addressed by printing 2D patterns of vascular cells onto biopaper substrates. Composite biopapers made of a mechanically supportive polymer scaffold and extracellular matrix-like hydrogel could sustain differentiation and network formation of printed vascular cells, while enabling transfer and stacking of individual biopapers to form thick 3D constructs. We have used several different polymer and hydrogel materials to make composite biopapers including polylactidecoglycolide (PLGA), polydimethylsiloxane (PDMS), MatrigelTM and collagen. Biological laser printing (BioLP) was then used to print patterns of vascular endothelial cells onto the biopapers. The vascular cells differentiated postprinting, stretching to form networks that retained the printed structure as well as forming smaller spontaneous outgrowths. After the onset of vascular differentiation, the biopapers were stacked, cultured and observed with confocal microscopy. Interlayer boundaries were defined with fluorescent beads so that cell migration and networking could be observed between layers. Additional experiments were performed to move towards a 3D brain model by printing vascular cells onto biopapers preseeded with astrocytes. These results demonstrate the feasibility of stackable biopapers as a way to build 3D vascularized tissues with a 2D cell printing technique.

Dr. Bradley Ringeisen is Head of the Bioenergy and Biofabrication Section at the U.S. Naval Research Laboratory (NRL). He is currently on loan to the Defense Threat Reduction Agency (DTRA) Joint Science and Technology Office (JSTO) as a science and technology manager in the Diagnostics and Disease Surveillance Division. He has been tasked as the Project Lead for DTRA/JSTO’s 24 month diagnostics challenge, which is a program that will demonstrate the linkage of point


ofcare/pointofneed diagnostic devices with an informaticsbased, biosurveillance ecosystem.

I will also discuss two projects that are beginning this year in my laboratory. We are engineering two 3D tissue models (lung and blood


-brain-barrier) for in vitro infection and diagnostic biomarker discovery experiments. Aerosolized Burkholderia pseudomallei will be exposed to the lung model while Venezuelan equine encephalitis virus (VEEV) will be exposed to the blood-brain-barrier model. Each model will utilize stacked biopaper and cell printing approaches. A second program will engineer an active acute care covering to stabilize wounds. This project will be developing autonomous materials with bioactive properties including antimicorbials, hemostasis agents and dynamic shape. We are searching for qualified postdoctoral candidates to work on these projects, and I will be available after the seminar to discuss potential opportunities.

During his postdoctoral position, Dr. Ringeisen performed the first successful laser induced forward transfer printing experiment on a living cell. He was hired as a research chemist at NRL in 2002 and currently maintains a six member research group. This group has a wide range of research interests that include the study of microbial extracellular electron transfer, biofuel production, the bio/nano interface, stem cell/material interactions as well as cell and tissue printing for medical and diagnostic applications.

Virginia Tech – Wake Forest University School of Biomedical Engineering and Sciences 317 ICTAS, Stanger St., (0298) Blacksburg, Virginia 24061 • 540-231-8191 •

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