A High-Throughput Platform To Investigate Angiogenesis In Perfused Human Capillaries
In short, there has been no description or success of creating actual human capillaries in vitro which are perfused with an appropriate fluid to deliver nutrients to a 3-D tissue. We have solved this problem by mimicking the in-vivo formation of angiogenesis using a precisely fabricated platform.
The potential impact of mimicking the in-vivo formation of angiogenesis using a precisely fabricated platform can be encompassed in the broad areas of oncogenesis, ischemia, arterio-venous malformations, wound healing, drug delivery, and tissue growth, differentiation, and death. For example, the growth and development of tumors is a 3-D process that requires recruitment of host vessels for delivery of nutrients and metastasis of cells. All major modes of pharmacotherapy (e.g., oral, subcutaneous, intravenous, intramuscular) involve uptake and delivery of the drug by the circulatory system including the microcirculation. Capillary permeability and high-throughput screening are major areas of investigation which could be addressed by our proposed system. Finally, the "decision" by a tissue following insult to revitalize or undergo programmed death is poorly understood, yet is fundamental for our success in advancing human health, and must depend on a functional (Le., perfused) capillary bed.
The challenge to create an in-vitro perfused human capillary bed represents a completely new paradigm in the creation of 3-D tissues. By definition, a 3-D tissue requires enhanced transport of nutrients and waste relative to 2-D monolayer cultures. Current approaches to create such an environment have employed three primary approaches: 1) enhanced concentration gradients of nutrients and waste while relying on molecular diffusion (Brownian motion) as the mode of transport, 2) the creation of microchannels in the tissue to enhance advection (forced convection), or 3) forced interstitial fluid flow. In-vivo, diffusion of nutrients and waste is the mechanism of transport once solutes exit the capillary bed, and is generally limited to distances <250 J.1m. The rate of transport is proportional to the concentration difference between two points, and inversely related to the separation distance. Hence, numerous 3-D tissue models have been reported with dimensions on the order of 1-10 mm by simply enhancing the oxygen tension (room air is 160 mmHg compared to 20-30 mmHg in the interstitial tissue) and concentration of other nutrients (e.g., glucose). More recently, microfabrication technology has led to the creation of precise microchannels on non-biological substrates (e.g., silicon or polydimethyl siloxane, PDMS) or within biological substrates such as collagen. While these approaches offer the distinct advantage of introducing advection as a mechanism of transport, even when "endothelialized", the channels are not human capillaries. Hence, while this approach may assist the creation of larger engineered tissues, they are of less benefit in understanding angiogenesis, cell migration, cell differentiation, and ischemia. Interstitial fluid flow can markedly impact extracellular gradients of solutes, enhance transport of nutrients and waste, and significantly impact the development of both lymphatic and blood capillaries. These recent studies, as well as others including our group, highlight the ability to generate capillaries in 3-D, and also demonstrate that these capillaries can become functional upon implantation. However, perfusion of human (or other animal) capillaries in-vitro has not been demonstrated. In short, there has been no description or success of creating actual human capillaries in vitro which are perfused with an appropriate fluid to deliver nutrients to a 3-D tissue. We have solved this problem by mimicking the in-vivo formation of angiogenesis using a precisely fabricated platform.
Patent Number: US20120083425A1
Application Number: US13253820A
Inventor: George, Steven C. | Hughes, Christopher C.W. | Lee, Abraham P. | Moya, Monica | Hsu, Yu-Hsiang
Priority Date: 5 Oct 2010
Priority Number: US20120083425A1
Application Date: 5 Oct 2011
Publication Date: 5 Apr 2012
IPC Current: C40B003006 | C40B004002 | C40B005006
US Class: 506010 | 506014 | 506026
Title: High-Throughput Platform Comprising Microtissues Perfused With Living Microvessels
Usefulness: High-Throughput Platform Comprising Microtissues Perfused With Living Microvessels
Summary: The process is useful for creating a 3D metabolically active network of living microvessels such as arterioles, capillaries and venules.
Novelty: Creating a 3D metabolically active network of living microvessels e.g. arterioles, comprises preparing a template comprising a micro fluidic and microtissue channels, and providing a stimulus to the microfluidic channels
Biomedical
Medical Imaging
9810685
Tech ID/UC Case 21077/2009-437-0 Related Cases 2009-437-0
USA
