Name: shape memory polymers for active cell culture
Uploaded: 2011-07-04T15:00:00
Description: Watch this Scientific Journal Video about Shape Memory Polymers for Active Cell Culture at JoVE.com

The authors would like to thank Kelly A. Burke for technical assistance with ACC substrate preparation. Based on the article published in Biomaterials, Davis KA, et al., Dynamic cell behavior on shape memory polymer substrates, Biomaterials, doi:10.1016/j.biomaterials.2010.12.006, Copyright Elsevier (2011). This material is based upon work supported by NSF under Grant No. DMR-0907578.

1. Isothermal UV-Curing of NOA63
<ol>
<li>A custom curing chamber was developed using a glass slide (75 mm x 25 mm x 1 mm), a 1 mm thick Teflon spacer, and an aluminum plate (75 mm x 25 mm x 3 mm) as shown in Figure 1. The chamber is held together using small binder clips.</li>
<li>Inject the NOA63 into the chamber through a hole in the Teflon spacer using an 18 gauge needle. The NOA63 can be gently heated to ease injection.</li>
<li>Place the chamber on a hot plate set at 125 &deg;C and allow to heat ...

<ol>
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The Tg of NOA63 can be easily controlled via the curing temperature. We used this to generate SMP substrates that can be triggered in a cell compatible range. NOA63 is plasticized by water which lowers the dry Tg, so we increased the dry Tg by curing at 125 &deg;C to move the wet Tg range between 30 and 37 &deg;C.
The active cell culture substrates demonstrated are able to control cell behavior. The results of microfilament reorganization highlight the potentia...

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		<tr>
			<td>Name of the reagent or instrument</td>
			<td>Company</td>
			<td>Catalogue number</td>
			<td>Comments (optional)</td>
		</tr>
		<tr>
			<td>NOA63</td>
			<td>Norland Products Inc.</td>
			<td>NOA63</td>
			<td>Lot number 111</td>
		</tr>
		<tr>
			<td>Dogbone Punch</td>
			<td>TestResource, Inc. Shakopee, MN</td>
			<td>&nbsp;</td>
			<td>Scaled-down Type IV dogbone (ASTM D638-03)</td>
		</tr>
		<tr>
			<td>Benchtop Hydraulic Press</td>
			<td>Carver</td>
			<td>3851</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>C3H10T1/2 Mouse Embryonic Fibroblasts</td>
			<td>ATCC</td>
			<td>CCL-226</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Biological Safety Cabinet</td>
			<td>Thermo Fisher</td>
			<td>1357</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>UV Lamp</td>
			<td>Spectroline</td>
			<td>SB-100PC</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Dynamic Mechanical Analyzer (DMA)</td>
			<td>TA Instruments, Inc.</td>
			<td>Q800</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Inverted Fluorescence Microscope</td>
			<td>Leica</td>
			<td>Leica DMI 4000B</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Confocal Laser Scanning Microscope</td>
			<td>Zeiss</td>
			<td>LSM 710</td>
			<td>20x/0.8 NA air or a 40x/1.30 NA oil objective</td>
		</tr>
	</tbody>
</table>

shape memory polymers for active cell culture

Shape memory polymers (SMPs) are a class of "smart" materials that have the ability to change from a fixed, temporary shape to a pre-determined permanent shape upon the application of a stimulus such as heat1-5. In a typical shape memory cycle, the SMP is first deformed at an elevated temperature that is higher than its transition temperature, Ttrans [either the melting temperature (Tm) or the glass transition temperature (Tg)]. The deformation is elastic in nature and mainly leads to a reduction in conformational entropy of the constituent network chains (following the rubber elasticity theory). The deformed SMP is then cooled to a temperature below its Ttrans while maintaining the external strain or stress constant. During cooling, the material transitions to a more rigid state (semi-crystalline or glassy), which kinetically traps or "freezes" the material in this low-entropy state leading to macroscopic shape fixing. Shape recovery is triggered by continuously heating the material through Ttrans under a stress-free (unconstrained) condition. By allowing the network chains (with regained mobility) to relax to their thermodynamically favored, maximal-entropy state, the material changes from the temporary shape to the permanent shape.
Cells are capable of surveying the mechanical properties of their surrounding environment6. The mechanisms through which mechanical interactions between cells and their physical environment control cell behavior are areas of active research. Substrates of defined topography have emerged as powerful tools in the investigation of these mechanisms. Mesoscale, microscale, and nanoscale patterns of substrate topography have been shown to direct cell alignment, cell adhesion, and cell traction forces7-14. These findings have underscored the potential for substrate topography to control and assay the mechanical interactions between cells and their physical environment during cell culture, but the substrates used to date have generally been passive and could not be programmed to change significantly during culture. This physical stasis has limited the potential of topographic substrates to control cells in culture.
Here, active cell culture (ACC) SMP substrates are introduced that employ surface shape memory to provide programmed control of substrate topography and deformation. These substrates demonstrate the ability to transition from a temporary grooved topography to a second, nearly flat memorized topography. This change in topography can be used to control cell behavior under standard cell culture conditions.

Watch this Scientific Journal Video about Shape Memory Polymers for Active Cell Culture at JoVE.com

Shape Memory Polymers for Active Cell Culture

A method for developing cell culture substrates with the ability to change topography during culture is described. The method makes use of smart materials known as shape memory polymers that have the ability to memorize a permanent shape. This concept is adaptable to a wide range of materials and applications.

Shape memory polymers (SMPs) are a class of "smart" materials that have the ability to change from a fixed, temporary shape to a pre-determined permanent ...

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