title: Creating stiffness gradient polyvinyl alcohol hydrogel using a simple gradual freezing-thawing method to investigate stem cell differentiation behaviors.
abstract: Polyvinyl alcohol (PVA) cylindrical hydrogel with a stiffness gradient was prepared using a simple liquid nitrogen (LN2)-contacting gradual freezing and thawing method in order to investigate the effects of substrate stiffness on stem cell differentiation into specific cell types. The prepared cylindrical PVA hydrogel showed a gradually increasing stiffness along the longitudinal direction from the top at approximately 1 kPa to the bottom (LN2 contacted side) at approximately 24 kPa. From the in vitro culture of bone marrow stem cells, it was observed that each soft (∼1 kPa) and stiff (∼24 kPa) hydrogel section promotes effective neurogenesis and osteogenesis of the cells, respectively, with the tendency to gradually decrease toward the opposing characteristic's side. The stiffness gradient cylindrical PVA hydrogel fabricated using this simple gradual freezing and thawing method can be a useful tool for basic studies, including the determination of optimum stiffness ranges for a variety of stem cell differentiations, as well as the investigation of cell migration in terms of substrate stiffness.
authors.affiliation: Department of Advanced Materials, Hannam University, Daejeon 305-811, Republic of Korea.
authors.forename: Tae Ho
authors.initials: TH
authors.lastname: Kim
authors.affiliation: Department of Advanced Materials, Hannam University, Daejeon 305-811, Republic of Korea.
authors.forename: Dan Bi
authors.initials: DB
authors.lastname: An
authors.affiliation: Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330-714, Republic of Korea.
authors.forename: Se Heang
authors.initials: SH
authors.lastname: Oh
authors.affiliation: Department of Advanced Materials, Hannam University, Daejeon 305-811, Republic of Korea.
authors.forename: Min Kwan
authors.initials: MK
authors.lastname: Kang
authors.affiliation: Department of Advanced Materials, Hannam University, Daejeon 305-811, Republic of Korea.
authors.forename: Hyun Hoon
authors.initials: HH
authors.lastname: Song
authors.affiliation: Department of Advanced Materials, Hannam University, Daejeon 305-811, Republic of Korea. Electronic address: jhlee@hnu.kr.
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000328:Adult; D015153:Blotting, Western; D002152:Calorimetry, Differential Scanning; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D019245:Compressive Strength / Q000187:drug effects; D003460:Crystallization; D004247:DNA / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005615:Freezing; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects; D008875:Middle Aged; D011142:Polyvinyl Alcohol / Q000737:chemistry* / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D044366:Transition Temperature; D014961:X-Ray Diffraction
chemical_list: C062364:polyvinyl alcohol hydrogel; D011142:Polyvinyl Alcohol; D004247:DNA
keywords: Differentiation; Hydrogel; Polyvinyl alcohol; Stem cell; Stiffness gradient