(585ag) Tissue Patterning By Spatially Defined Addressable Microfluidic Delivery of Differentiated Growth Factors

Now that tissue engineering is targeting organs of high complexity, the design and manufacturing of scaffold should take into account all of these factors: (1) Active Microfluidic Pores for Delivery of Nutrients, Oxygen and Chemical Signals Throughout the Scaffold, (2) Transparent Material for Microscopy Observation, Understanding Tissue Growth in Artificial Environments, (3) “Addressable” Design for Localized Chemical Delivery and/or Sampling, (4) Cell Control, Tissue Patterning, Monitoring Tissue Development. Therefore, an ’addressable’ microfluidics platform will be modified to deliver predetermined amounts of growth-factors to specified XY locations within the chip. And continuous real-time feedback for differentiation-guiding will be accomplished by coupling valve automation with robotized microscopy, computer vision and transport modeling of the chemo-stimuli release within the device. The deliverables will be: A) an experimental platform capable of precise chemo-stimuli delivery to single cells, and B) a computational framework capable of adaptive tissue patterning. Since this platform is lacking in previous works, we aim to provide a proof-of-concept of an adaptive control of cellular differentiation via an addressable release platform. The platform is a microfluidic device consisting of four layers of polydimethylsiloxane (PDMS) elastomer which is connected to an automatic pumping system controlled by Matlab code. The first layer locating on top of the chip acts as a valve which helps switching the flow of media in the second layer between through and by-passing delivery holes in the third layer. These holes are used to deliver differentiation factors to a cell chamber located at the bottom of the chip. Using this platform, we assessed the ability to adaptively control the tissue formation of mouse embryonic fibroblasts by platelet-derived growth factor-BB (PDGF-BB) gradients. Cell behavior is monitored in real time using an automated microscope while the translocation of the cells is purposely navigated to various locations in a migration chamber in an addressable manner through an adjustable chemoattractant delivery.