Low Rigidity Gels for MSC Growth Modulation

Abstract

This invention provides gels and matrices having a rigidity in the range of 0.1-2.5 kPa, methods of manufacturing same, and method of preserving a mesenchymal stem cell population or studying mesenchymal stem cells, comprising same.

1 . A method of modulating development of a mesenchymal stem cell, comprising the step of suspending the mesenchymal stem cell in a gel matrix comprising a gelling agent wherein said gel matrix is coated with a type 1 collagen, a fibronectin, or a combination thereof and wherein said gel matrix is maintained at a predetermined rigidity; and exposing the gel matrix to a growth modulating factor. 
     
     
         2 . The method of  claim 1 , whereby the growth modulating factor is a physical factor, a chemical factor or their combination. 
     
     
         3 . The method of  claim 2 , whereby the physical factor is pressure, temperature or their combination. 
     
     
         4 . The method of  claim 2 , whereby the gel matrix further comprises the chemical factor that is an induction medium. 
     
     
         5 . The method of  claim 2 , whereby exposure to the chemical or physical factor results in an increase in the rigidity of the gel matrix. 
     
     
         6 . The method of  claim 5 , whereby the rigidity of the gel matrix is increased to coincide with the rigidity of the ECM in the microenvironment the mesenchymal stem cell is sought to differentiate into. 
     
     
         7 . The method of  claim 1 , whereby the gelling agent is a recombinant fibrin or fibrinogen protein. 
     
     
         8 . The method of  claim 7 , whereby the concentration of said recombinant fibrin or fibrinogen protein in said gel matrix is 1-20 mg/mL. 
     
     
         9 . The method of  claim 7 , whereby the recombinant fibrin or fibrinogen protein is a fibrin or fibrinogen protein of a heterothermic animal. 
     
     
         10 . The method of  claim 1 , whereby the gel matrix is a 2-dimensional gel matrix. 
     
     
         11 . The method of  claim 1 , whereby the gel matrix is a 3-dimensional gel matrix. 
     
     
         12 . The gel matrix of  claim 1 , wherein said gel matrix further comprises a serum selected from a bovine serum and a horse serum. 
     
     
         13 . The gel or matrix of  claim 1 , wherein said gel or matrix further comprises a protease inhibitor. 
     
     
         14 . The method of  claim 1 , whereby the gel matrix has a rigidity of between about 0.1 and 2.5 kPa 
     
     
         15 . The method of  claim 1 , whereby the gel matrix further comprises an adhesion protein. 
     
     
         16 . The method of  claim 1  whereby the gel matrix is a fibronectin/collagen mixture. 
     
     
         17 . (canceled) 
     
     
         18 . A method for inducing or maintaining quiescence and sustaining biological activity in a somatic stem cell ex vivo, comprising: contacting the somatic stem cell with a gel matrix comprising an extracellular material that bind to integrin on the membrane of the somatic stem cell, said gel matrix having a substantially similar elasticity to the elasticity of the predominant in vivo biological microenvironment of the somatic stem cell of the same type in vivo; and providing the somatic stem cell with nutrient material for sustaining biological activity of the somatic stem cell ex vivo. 
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . A method for inducing proliferation ex vivo in the somatic stem of  claim 18 , comprising the step of contacting the somatic stem cell ex vivo with a proliferation-inducing material comprising a gel matrix that attach to integrin on the surface of the somatic stem cell said gel matrix having a lower elasticity than the elasticity of the somatic cell in vivo biological microenvironment; and providing nutrient-growth material for promoting proliferation and sustaining biological activity of the somatic stem cell and its progeny ex vivo. 
     
     
         23 . (canceled) 
     
     
         24 . A method for inducing differentiation ex vivo in the somatic stem cell of  claim 22 , comprising the step of: contacting the somatic stem cell with a differentiation material comprising chemical stimuli selected to stimulate differentiation of the somatic stem cell to a predetermined cell type; and providing the differentiated cell with differentiated-cell nutrient material for sustaining biological activity of the differentiated cell. 
     
     
         25 . (canceled) 
     
     
         26 . A somatic stem cell induced or maintained in quiescence and sustained in biological activity according to any one of  claim 18 . 
     
     
         27 . (canceled) 
     
     
         28 . (canceled)