Student Award Winner in the Master’s Degree Category for the Society for Biomaterials 34th Annual Meeting, Seattle, Washington, April 21–24, 2010 Cell culture platform with mechanical conditioning and nondamaging cellular detachment Elaine L. Lee, Horst A. von Recum Department of Biomedical Engineering, Case Western Reserve University, Wickenden 220, 10900 Euclid Avenue, Cleveland, Ohio 44106 Received 30 November 2009; accepted 10 December 2009 Published online 22 February 2010 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jbm.a.32754 Abstract: Cells implanted after injury may remodel undesir- ably with improper mechanical stimulation from surround- ing tissue. Proper conditioning of tissue engineered constructs before implantation can lead to suitable tissue architectures, along with an extracellular matrix (ECM) envi- ronment that more closely mimics native tissue. Addition- ally, cell implantation without bulky polymeric scaffolding is often desirable. Previous researchers have created devices capable of applying mechanical forces to cells (e.g., stretch) but cellular removal from these devices, such as by trypsin, often results in irreversible damage. Conversely, devices are available that can detach intact cells, but these are inelastic, nonstretchable substrates. We have created a cell culture platform that allows for mechanical conditioning and then subsequent nondamaging detachment of those cells. We have modified silicone culture surfaces, to incorporate ther- mally responsive polymers of N-isopropylacrylamide (NIPAAm) to create an elastic substrate that can also change surface properties with temperature change. A copolymer of NIPAAm and 10% w/w acrylic acid (AAc) was conjugated to an amine-bonded silicone surface through carbodiimide chemistry. Cells were able to attach to the resulting surfaces at 37  C and showed detachment by rounded morphology at 25  C. Following mechanical stretching, cells were still able to spontaneously detach from these modified silicone surfa- ces with temperature change. V C 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 93A: 411–418, 2010 Key Words: P(NIPAAm), silicone, cell detachment, mechani- cal conditioning, bioreactor INTRODUCTION Advances in cell therapy have demonstrated remarkable potential for therapeutic management of diseases and for improving function to damaged tissue. 1–8 However, cells implanted after injury may remodel undesirably with improper mechanical stimulation from surrounding tissue. Proper conditioning of tissue engineered constructs before im- plantation can lead to suitable tissue architectures, as well as extracellular matrix (ECM) growth that more closely mimics native tissue. Additionally, polymeric implant materials may elicit undesired responses, such as inflammation, even with degradable materials. A strategy that can deliver cells in pre- fabricated natural ECM scaffolding without implanting extra- neous bulky polymers is highly desirable. 2,6,8 ECM allows cells to adhere, grow, migrate, and differen- tiate, as well as functionally sustain mechanical forces such as stress, tension, compression, and shear to allow cells to maintain shape. 9 As both stem cells and transplanted cells are highly sensitive to surrounding environmental stimuli, the load demands at an injury site may heavily influence a random alignment of cells, and may even lead to undesired remodeling or cell death. 9–18 As demonstrated in stem cells, 19,20 smooth muscle cells, 21 endothelial cells, 22 and var- ious cardiovascular tissues, 23,24 mechanical conditioning before implantation may provide such cellular orientation and ECM growth stimulus. 25 Cells subjected to cyclic deformations, such as cardiomy- ocytes, will elongate and orient perpendicularly to the axis of deformation. 25–28 The kinds and magnitudes of mechani- cal stresses acting on the tissue can influence the growth of the ECM. By manipulating the types and magnitudes of stresses applied, researchers can manage the gene expres- sion, which effects cell differentiation and ECM protein secretion, influencing the overall mechanical properties and success rate of engineered tissue. 29 However, while present mechanical conditioning meth- ods use flexible substrates such as collagen and silicone, these devices cannot detach cells without damage. 25,30–33 Correspondence to: H. A. von Recum; e-mail: horst.vonrecum@case.edu Contract grant sponsors: American Heart Association (Predoctoral Fellowship), Center for Stem Cell and Regenerative Medicine (Pilot Award), State of Ohio V C 2010 WILEY PERIODICALS, INC. 411