MINNESOTA Engineered Tissues for Long-Term Measurement of Vascular Contractility Patrick W. Alford (PI), Eric S. Hald, Kerianne E. Steucke, Zaw Win Biomedical Engineering, University of Minnesota NNIN Facility utilized: Minnesota Nano Center NNIN University of Minnesota – 2013 DESCRIPTION OF WORK Use of photolithography to create patterns for PDMS stamps Stamps used to pattern extra cellular matrix proteins Use of photolithography to fabricate microfluidic protein delivery devices Patterned delivery of desired proteins for substrate functionalization and/or cell adhesion Development of a highly-aligned monolayer of vascular smooth muscle cells to mimic arterial lamellae MAJOR OBSERVATIONS Microfluidic devices yield highly-confluent, highly- aligned tissues that mimic native arterial lamellae and are similar to those fabricated using traditional microcontact printing methods Microfluidic protein patterning allows for long-term surface functionalization of PDMS substrates with genipin, allowing for increased temporal tissue viability and long-term vascular contractility experimentation Long-Term Microfluidic Tissue Fabrication Procedure Temporal Comparison of Fabrication Techniques Schematic of Contractility Experiment Scale bars: 200 μm
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MINNESOTA
Engineered Tissues for Long-Term Measurement of Vascular ContractilityPatrick W. Alford (PI), Eric S. Hald, Kerianne E. Steucke, Zaw Win
Biomedical Engineering, University of MinnesotaNNIN Facility utilized: Minnesota Nano Center
NNIN University of Minnesota – 2013
DESCRIPTION OF WORK Use of photolithography to create patterns
for PDMS stamps Stamps used to pattern extra cellular
matrix proteins Use of photolithography to fabricate
microfluidic protein delivery devices Patterned delivery of desired proteins
for substrate functionalization and/or cell adhesion Development of a highly-aligned
monolayer of vascular smooth muscle cells to mimic arterial lamellae
MAJOR OBSERVATIONS Microfluidic devices yield highly-confluent, highly-
aligned tissues that mimic native arterial lamellae and are similar to those fabricated using traditional microcontact printing methods
Microfluidic protein patterning allows for long-term surface functionalization of PDMS substrates with genipin, allowing for increased temporal tissue viability and long-term vascular contractility experimentation
Schematic of Contractility Experiment Scale bars: 200 μm
MINNESOTANNIN University of Minnesota – 2013
Capture of Isolated Single Muscle FibersEdgar Arriaga (PI), Matthew Keefe
Chemistry, University of MinnesotaNNIN Facility utilized: Minnesota Nano Center
OUTLINE OF WORK Soft-Photolithography techniques
were utilized at NFC to make SU-8 molds on 4” silicon disks for a microfluidic device capable of capturing single mouse muscle fibers
Equipment used included CEE precision spinners, Contact Mask Aligners, and P-16 surface profiler
MAJOR OBSERVATIONS SU-8 2050 was found to be the best negative
photoresist for achieving feature heights of ~100 micrometers
High aspect ratio of the SU-8 photoresist is perfectly suited for the detail required in this device
2-D schematic of two channeled device capable of capturing muscle fibers, fibers flow through device, and are trapped in the channels as they narrow. In the mold, the SU-8 is represented by the white spaces of the schematic, while the white spaces represent fluid filled channels in the actual PDMS device.
MINNESOTANNIN University of Minnesota – 2013
Cancer-on-a-ChipDavid Wood, Marie-Elena Brett, Alexandra Schonnesen, Alexandra Crampton
Biomedical Engineering, UMNNNIN Facility utilized: Minnesota Nano Center
DESCRIPTION OF WORK We have been working on a
microfluidic model for intravasation and extravasation in cancer metastasis.
Our lab uses the NFC facilities to fabricate master molds using soft photolithography techniques
MAJOR OBSERVATIONS Using the capillary burst model for our design we
have been able to create cancer “tissues” within the microfluidic device and flow media adjacent to this tissue acting as a blood vessel (below left)
Currently, media channels are lined with epithelial cells to create a more physiologically relevant blood vessel (below)
MINNESOTANNIN University of Minnesota – 2013
Sickle CellDavid Wood (PI), Xinran Lu, Craig Jonas, and Sarah Bening
Biomedical Engineering, University of MinnesotaNNIN Facility utilized: Minnesota Nano Center
DESCRIPTION OF WORK Our lab utilizes the nanofabrication
center at the University of Minnesota to create microfluidic devices capable of recapitulating physiological conditions in order to study Sickle Cell Disease.
Publications Wood DK, Soriano A, Mahadevan L, Higgins JM, Bhatia SN
(2012) A biophysical indicator of vaso-occlusive risk in sickle cell disease Sci Transl Med 4, 123ra26. PMID22378926
MAJOR OBSERVATIONS By creating these devices, we can flow diseased blood
through actually blood capillary sized channels and control the oxygen environment around the blood in hopes of discovering more about the process by which the disease affects patients.
We are also developing a computational model of sickle hemoglobin based on thermodynamic principles. The goal of the project is to inspire novel therapies by understanding the molecular events of polymerization.
DNA Stretching in Nanochannel ConfinementKevin D. Dorfman (PI), Julian Sheats, Damini Gupta
Chemical Engineering and Material Science, University of MinnesotaNNIN facility utilized: Minnesota Nano Center
DESCRIPTION OF WORK DNA molecules are injected into channels smaller
than the radius of gyration to induce elongation Extension and diffusion measured as a function of
channel size for rapid barcoding sequencing DNA molecules need to move smoothly through
channels in order to measure equilibrium properties.
MAJOR OBSERVATIONS Roughness in channel surface likely cause of
DNA sticking in channel. Residual conductive layer particles are the likely
cause of roughness during etch. Placing the conductive layer on top of the
ebeam resist removes roughness.
SEM micrograph showing fused silica nanochannel device prior to sealing. Roughness is obvious within nanochannel and around pillars in loading area.
SEM directly after conductively layer removal and ebeam development. Roughness has been removed by placing conductive layer above resist, which allows for its complete removal prior to etch (pitted area is merely the resist).
MINNESOTANNIN University of Minnesota – 2013
ZnO Nanowire Tactile SensorProf. Rusen Yang (PI), Kory Jenkins
Mechanical Engineering, University of MinnesotaNNIN Facility utilized: Minnesota Nano Center
Goal: Develop flexible, ZnO nanowire based sensor for replicating human touch perception.
Photo: Training test run. ZnO seed layer on top of Cr layer using AJA sputtering system. Uniform, high quality result.
MINNESOTANNIN University of Minnesota – 2013
Microfluidics-Based in Vivo Mimetic Systems for the Study of Cellular BiologyChristy L. Haynes (PI), Donghyuk Kim, Xiaojie Wu
Chemistry, University of MinnesotaNNIN Facility utilized: Minnesota Nano Center
DESCRIPTION OF WORK Investigation of neutrophil chemotaxis under
various stimuli (different chemoattractants or cytokines, enzyme inhibitor, other cell types, and drug effects)
Evaluation of platelet adhesion upon exposure to mesoporous silica nanoparticles
Publications Kim, D.; Haynes, C. L. Analyst 2013, 138, 6826-6833. Kim, D.; Haynes, C. L. Anal. Chem. 2013, 85, 10787-10796. Kim, D.; Finkenstaedt-Quinn, S.; Hurley, K. R.; Buchman, J. T.;
Haynes, C. L. Analyst 2014, DOI: 10.1039/c3an01679j. Wu, X.; Kim, D.; Young, A. T.; Haynes, C. L. in prep.
MAJOR OBSERVATIONS The presence of various stimuli regulates neutrophil
chemotactic behaviors by influencing hierarchy of chemoattractants and migration rates.
Surface marker expression is altered in the context of neutrophil activation compared to naïve cells.
High nanoparticle doses increase platelet adhesion and aggregation on endothelial cell layer.
