title: Heparin-hyaluronic acid hydrogel in support of cellular activities of 3D encapsulated adipose derived stem cells.
abstract: We have developed stem cell-responsive, heparin-hyaluronic acid (Hep-HA) hydrogel, crosslinked by thiolated heparin (Hep-SH) and methacrylated hyaluronic acid (HA-MA) via visible light mediated, thiol-ene reaction. Physical properties of the hydrogel (gelation time, storage modulus, and swelling ratio) were tunable by adjusting light intensity, initiator/polymer concentration, and precursor pH. Culture of human adipose derived mesenchymal stem cells (ADSCs) using this hydrogel was characterized and compared with the control hydrogels including Hep-PEG hydrogel, PEG-HA hydrogel. Sufficient initial adhesion and continuous proliferation of ADSCs in 2D were observed on both heparin-containing hydrogels (Hep-HA and Hep-PEG hydrogel) in contrast to no adhesion of ADSCs on PEG-HA hydrogel. On the other hand, in the case of 3D culture of encapsulated ADSCs, efficient cellular activities such as spreading, proliferation, migration, and differentiation of ADSCs were only observed in soft Hep-HA hydrogel compared to Hep-PEG or PEG-HA hydrogel with the similar modulus. The upregulated expressions of hyaluronidases in ADSCs encapsulated in Hep-HA hydrogel compared to the control hydrogels and effective degradation of the hydrogel by hyaluronidase imply that the degradation of hydrogel was necessary for 3D cellular activities. Thus, Hep-HA hydrogel, where heparin acts as a binding domain for ADSCs and HA acts as a degradation site by cell secreted enzymes, was efficient for 3D culture of human ADSCs without any additional modification using biological/chemical molecules.
  
  
  
  Stem cell-responsive hydrogel composed of heparin and hyaluronic acid was prepared by visible light-mediated thiol-ene reaction. Without additional modification using functional peptides for cell adhesion and matrix degradation, ADSCs encapsulated in this hydrogel showed efficient cellular activities such as spreading, proliferation, migration, and differentiation of ADSCs whereas control hydrogels missing heparin or hyaluronic acid could not support cellular activities in 3D. In this hydrogel, heparin mainly acts as a binding domain for stem cells and hyaluronic acid mainly acts as a degradation site by ADSC secreted enzymes, but interrelated synergistic functions of heparin and HA were observed. Therefore, we speculate that this hydrogel can serve as a promising carrier for stem cell based therapy and various tissue engineering applications.
authors.affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea.
authors.forename: Kihak
authors.initials: K
authors.lastname: Gwon
authors.affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea.
authors.forename: Eunsol
authors.initials: E
authors.lastname: Kim
authors.affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea; Center for Theragnosis, Biomedical Research Institute, KIST, Seoul 02792, Republic of Korea. Electronic address: gytae@gist.ac.kr.
authors.forename: Giyoong
authors.initials: G
authors.lastname: Tae
mesh_terms: D050156:Adipogenesis / Q000187:drug effects; D000273:Adipose Tissue / Q000166:cytology*; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002478:Cells, Cultured; D005782:Gels; D006493:Heparin / Q000494:pharmacology*; D006820:Hyaluronic Acid / Q000494:pharmacology*; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D008027:Light; D008422:Materials Testing; D055595:Mechanical Phenomena; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000187:drug effects; D018874:Spheroids, Cellular / Q000166:cytology / Q000187:drug effects; D013234:Stem Cells / Q000166:cytology*; D034421:Sus scrofa
chemical_list: D005782:Gels; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D006820:Hyaluronic Acid; D006493:Heparin
keywords: Adult stem cell; Degradation; Encapsulation; Hyaluronidase; Migration