An invention of thermo-responsive polymer surface, yielding cell sheet based regenerative therapies in cardiology and ophthalmology

• Published in: Journal of stem cells & regenerative medicine 2015-01, Vol.11 (2), p.51-53
• Main Authors: Sawa, Yoshiki, Cherian, Kottoorathu Mammen, Mohanty, Sujata, Ganesh, Jegatheesan Saravana, Abraham, Samuel Jk
• Format: Article
• Language: English
• Subjects: Proceedings of the Inventions- Inter-Disciplinary Interactions and Solutions (IIDIAS) Session; The Inventions- Inter-Disciplinary Interactions and Solutions (IIDIAS)
• ISSN: 0973-7154; 0973-7154
• DOI: 10.46582/jsrm.1102010

The Invention: In vitro cell culture methodologies provide a conducive environment for the cells taken out of their native environment to grow and proliferate in a non-physiological environment, the culture dish. Research experiments have been focusing on various criteria for assessing how far it is possible to recapitulate the native extra-cellular environment in vitro. Scaffolds, culture media, growth factors and cell surface modified culture dishes are some of the components that provide a conducive environment for in vitro cell culture. Cells that are grown in culture dishes using conventional methodologies are usually detached using enzymatic treatment with Trypsin, Collagenase etc [1], to be transplanted when it comes to a clinical or experimental application. Such enzymes used in separating the cells may have some damaging effects to the cell membranes which might impair the cell function [1]. However, cells if can be grown as a monolayer and be harvested as a contiguous cell sheet, it is considered suitable for transplantation in certain specific applications. In addition to that, if enzymatic digestion which has some detrimental effects on the detached cells could be avoided, that is an added advantage. The work by Prof. Okano and team from the Tokyo Women's Medical University, Japan, on thermo-responsive polymer surfaces has yielded a solution which has both the advantages viz., detachability of cells grown as a monolayer in the form of a cell sheet, that too without the use of enzymes. Their research into biomaterials for more than two decades has yielded a thermo-responsive polymer, the poly(N-isopropylacrylamide) (PIPAAm) [1] coated culture dish for cell sheet engineering. In their technology, PIPAAm is polymerized and grafted to tissue culture polystyrene (TCPS) dishes. Cells have been found to grow confluent on PIPAAm-TCPS at 37 °C. Once confluent as a monolayer, by merely reducing the temperature of the PIPAAm-TCPS to 20 °C, it can be easily detached as a single contiguous cell sheet. The alteration of the surface from a hydrophobic to a hydrophilic state with the lowering of the temperature from 37 °C to 20 °C enables this easy separation which is the unique feature of this technology [2]. Different kinds of cells have been shown to adhere to, spread over the PIPAAm gel modified TCPS (PIPAAm-TCPS) and grow as cell sheets without any change in their respective phenotypes [2]. Inter-Disciplinary-Interaction: I, based on the Invention: Cardio