IDF No.: LU-061114-01
Lead Inventor: Yaling Liu
Department: Bioengineering, Mechanical Engineering & Mechanics
Patent Status: Issued US Patent 10,870,823 and Pending US Patent App. No.: 17/130,142
Summary:
This novel invention is a biomimetic microfluidic platform that can prototype an in-vivo blood vessel outside the human body. The platform integrates an endothelial cell layer in a microfluidic channel, which can be subjected to specific flow and chemokine stimulations. It consists of a top and bottom channel separated by a semi-permeable, porous, cell culture friendly membrane. Endothelial cells that form the inner lining of blood vessels are coated on the semi-permeable membrane in the top channel. The microfluidic channel platform is designed such that it allows specific sections to access the top channel from the bottom channel, which allows spatially controlled stimulation of these endothelial cells from the basal side. This in-vitro blood vessel model can serve as a generic platform to study targeted drug delivery (ligand-receptor specificity, drug carrier features, hemorheology factors), cardiovascular conditions (atherosclerosis, drug-eluting stents), and immunology (inflammation, leukocyte adhesion, and migration). In addition, this microfluidic technology can perform explicit studies on patient-specific blood vessels (design channel geometries specific to a patient's blood vessel and integrate endothelial cells from the patient) to understand the best treatment strategy for a disease condition or study various factors that culminated in the onset of a disease condition. This novel invention addresses the needs of a blood vessel model that can cater to the demands for patient-specific therapeutics, as well as provide a more realistic platform to enhance current conventional drug development studies.
This novel microfluidic blood vessel model has advantages over in-vivo and animal blood vessel models, as well as, surpassing current gold standard in-vitro works on a petri dish and flow chamber platforms.
TECHNICAL DESCRIPTION:
The microfluidic device channels of the invention are made of polydimethylsiloxane (PDMS) with the top channel having dimensions of 2 cm long and a width of 350 μm. The bottom channel is 5 mm long and 1 mm wide and is arranged perpendicular to the top channel forming a cross shape. The top channel is bonded to the bottom channel with the semi-permeable membrane in between the two. This design enables the endothelial cells growing on the top channel to be locally accessed from the bottom channel. The device design can also be tuned to patient specific blood vessel dimensions and geometries. By obtaining a scan image of a blood vessel under study, a template could be created to cast the patient specific microfluidic channels in order to simulate disease conditions and treatments.
A layer of mammalian endothelial cells can be incorporated in a flow channel of patient specific dimensions and geometry and subjected to hemodynamic and biochemical environment observed in-vivo through external flow pumps. The device is inexpensive to manufacture and can be easily integrated to state-of-the-art analysis platforms for result of higher signal to noise ratio when compared to animal studies. The microfluidic nature of the device also requires minimal sample volumes.
Advantages:
- The device has a novel bi-layer design where the top and bottom channels are separated by a semi-permeable membrane. Endothelial cells are grown on the cell culture friendly, semi-permeable membrane, rather than glass or other substrates as in other platforms.
- The endothelial cells growing in the top channel of the bi-layer device can be subjected to physiological (flow, stretching, etc.) and biochemical (chemokine, enzyme stimulation) conditions to mimic an in-vivo environment.
- The bi-layer design of the device facilitates localized access to the top channel from the bottom channel. This enables site-specific chemokine treatment of the endothelial cells growing on the top channel. The device has the capability to study localized endothelial cell receptor expression levels and cell cycle pathways leading to their upregulation via cytokine treatment.
- The platform enables the in-situ study of targeted drug-loaded particle delivery onto endothelial cells subjected to inflammatory conditions.
- The device design can be tuned to patient-specific dimensions and geometries by obtaining a scan image of the patient’s blood vessel under study.
The device also has the capability to model organ-level functions by culturing different cell lines on the two sides of the membrane with the ability to study their cell-cell interactions. Different models that are possible are Lungs, Intestine (endothelial and epithelial cells); Blood-brain barrier (endothelial cells and nerve cells); Liver (endothelial cells and hepatocytes), etc.
The unique feature introduced into this microfluidic platform is a versatile combination of two layers of independently controllable channels, as well as the introduction of a semi-permeable membrane to allow coupling between the two layers. Currently, the membrane incorporated into the device is composed of polycarbonate, which functions well for cell seeding and growth. The introduction of the device’s bi-layer and semi-permeable membrane provides a platform advantage of a more realistic model of the boundary regions in the body where two types of tissue interact. The ability to more closely mimic conditions found in-vivo, allow for studies where exchange occurs within the human body. Such phenomena as nutrient exchange from digestive to circulatory tracts and gaseous exchange from the respiratory tract to tissues can also be studied. Another key capability of the semi-permeable membrane is that it permits localized expression of biomarkers by injecting triggering chemicals from one channel, allowing the diffusion across the membrane, and triggering the expression of certain biomarkers. The introduction of the semi-permeable membrane allows for an advantage in studies related to exchange, uptake, and delivery, above and beyond what the competitors currently offer, making the Lehigh platform well suited for studying nanomedicine delivery and other phenomena.
Additional Capabilities:
The bi-layer microfluidic system that has been developed at Lehigh is capable of facilitating active convective nutrient supply to populations of cancer cells. The microfluidic 3D culturing system has several advantages over current cancer growth techniques that are capable of producing physiologically relevant tumors in an expedited fashion while only requiring a small number of initial cancer cells. This 3D culturing system is believed to be the first attempt to grow cancers in an expedited fashion utilizing only a convective nutrient supply, which has the potential to offer improved drug screening for patients in clinical settings. A mathematical model has been developed which allows for adjustments to be made to the dynamic delivery of nutrients in order to efficiently use culture media without excessive waste.