US2011201117A1PendingUtilityA1

Forming porous scaffold from cellulose derivatives

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Assignee: AGENCY FOR SCIENCE TECNOLOGY AND RESPriority: Dec 18, 2007Filed: Dec 18, 2008Published: Aug 18, 2011
Est. expiryDec 18, 2027(~1.4 yrs left)· nominal 20-yr term from priority
Inventors:Zhilian YueFeng WenHanry Yu
A61L 27/56C08J 2201/0524Y10T428/249921C08J 2201/0484C08J 2301/28C08J 2201/026C08J 9/28Y10T428/249978C08J 2205/044C08L 1/14C08B 11/20B32B 3/26C08J 2201/024A61L 27/20Y10T428/249979C08J 2207/10
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Claims

Abstract

Scaffold comprises a polymer defining macropores and comprising hydroxypropylcellulose partially substituted by a substituent comprising a self-crosslinkable group, which is crosslinked through the self-crosslinkable group. The macropores have an average pore size larger than 50 microns and are at least partially interconnected. In one method, bicontinuous emulsion comprising a continuous aqueous phase and a continuous polymer phase is formed. The polymer phase comprises hydroxypropylcellulose partially substituted by a substituent comprising a self-crosslinkable group, and is crosslinked through the self-crosslinkable group to form a polymer defining at least partially interconnected pores. In another method, phase separation is induced in a solution comprising a polymer precursor and water to form a bicontinuous emulsion comprising a continuous polymer phase and a continuous aqueous phase. The polymer precursor comprises a self-crosslinkable group and is crosslinked through the self-crosslinkable group in the emulsion to form a polymer defining at least partially interconnected macropores.

Claims

exact text as granted — not AI-modified
1 . A scaffold comprising:
 a polymer defining macropores and comprising hydroxypropylcellulose partially substituted by a substituent, said substituent comprising a self-crosslinkable group, said partially substituted hydroxypropylcellulose being crosslinked through said self-crosslinkable group, said macropores having an average pore size of larger than 50 microns and being at least partially interconnected.   
     
     
         2 . The scaffold of  claim 1 , wherein said polymer has an interconnected porosity of about 50% or higher. 
     
     
         3 . The scaffold of  claim 1  or  claim 2 , wherein said polymer has a total porosity of about 80% or higher. 
     
     
         4 . The scaffold of any one of  claims 1  to  3 , wherein said macropores have a pore size distribution peaking at above 50 microns. 
     
     
         5 . The scaffold of any one of  claims 1  to  3 , wherein said macropores have a pore size distribution peaking at about 90 microns. 
     
     
         6 . The scaffold of any one of  claims 1  to  3 , wherein said macropores have a pore size distribution peaking at about 100 microns. 
     
     
         7 . The scaffold of any one of  claims 1  to  6 , wherein said polymer has an equilibrium water content of about 85%. 
     
     
         8 . The scaffold of any one of  claims 1  to  7 , wherein said polymer has a Young's modulus of about 10 to about 20 kPa in a hydrated state. 
     
     
         9 . The scaffold of any one of  claims 1  to  8 , wherein said self-crosslinkable group comprises an unsaturated double carbon-carbon bond. 
     
     
         10 . The scaffold of any one of  claims 1  to  9 , wherein said substituent comprises allyl isocyanate. 
     
     
         11 . The scaffold of any one of  claims 1  to  9 , wherein said substituent comprises methacrylic acid, acrylic acid, or glycidyl methacrylate. 
     
     
         12 . The scaffold of any one of  claims 1  to  11 , wherein said partially substituted hydroxypropylcellulose has a degree of substitution of less than about 2.5. 
     
     
         13 . The scaffold of any one of  claims 1  to  11 , wherein said partially substituted hydroxypropylcellulose has a degree of substitution of about 2.1. 
     
     
         14 . The scaffold of any one of  claims 1  to  13 , wherein said polymer is a gel. 
     
     
         15 . A method of forming a scaffold, comprising:
 forming a bicontinuous emulsion comprising a continuous aqueous phase and a continuous polymer phase, said polymer phase comprising hydroxypropylcellulose partially substituted by a substituent, said substituent comprising a self-crosslinkable group;   crosslinking said partially substituted hydroxypropylcellulose through said self-crosslinkable group to form a polymer defining at least partially interconnected pores.   
     
     
         16 . The method of  claim 15 , wherein said substituent comprises allyl isocyanate. 
     
     
         17 . The method of  claim 15 , wherein said substituent comprises methacrylic acid, acrylic acid, or glycidyl methacrylate. 
     
     
         18 . The method of any one of  claims 15  to  17 , wherein said pores comprise macropores. 
     
     
         19 . The method of any one of  claims 15  to  18 , wherein said crosslinking comprises irradiating said emulsion with γ-ray. 
     
     
         20 . The method of any one of  claims 15  to  19 , wherein said crosslinking comprises crosslinking at least about 90 wt % of said partially substituted hydroxypropylcellulose in said emulsion. 
     
     
         21 . The method of any one of  claims 15  to  20 , comprising removing water from said pores by freeze-drying said polymer. 
     
     
         22 . The method of  claim 21 , wherein, after said freeze-drying, said polymer has an interconnected porosity of about 50% or higher, and said pores have an average pore size of larger than 50 microns. 
     
     
         23 . The method of any one of  claims 15  to  22 , wherein said emulsion comprises about 80 to about 90 wt % of said aqueous phase and about 10 to about 20 wt % of said polymer phase. 
     
     
         24 . The method of any one of  claims 15  to  23 , wherein said partially substituted hydroxypropylcellulose has a degree of substitution of about 2.5 or less. 
     
     
         25 . The method of any one of  claims 15  to  24 , wherein said partially substituted hydroxypropylcellulose has a degree of substitution of about 2.1. 
     
     
         26 . The method of any one of  claims 15  to  25 , wherein said polymer is a gel. 
     
     
         27 . The method of any one of  claims 15  to  26 , wherein said emulsion is formed by subjecting a solution comprising water and said partially substituted hydroxypropylcellulose to heat treatment. 
     
     
         28 . The method of any one of  claims 15  to  27 , wherein said heat treatment comprises heat treatment at a temperature of about 313 K for about 5 minutes. 
     
     
         29 . A method of forming a scaffold, comprising:
 inducing phase separation in a solution comprising a polymer precursor and water, to form a bicontinuous emulsion comprising a continuous polymer phase and a continuous aqueous phase, said polymer precursor comprising a self-crosslinkable group;   crosslinking said polymer precursor through said self-crosslinkable group in said emulsion to form a polymer defining at least partially interconnected macropores.   
     
     
         30 . The method of  29 , wherein said polymer precursor is a cellulose derivative. 
     
     
         31 . The method of  claim 30 , wherein said cellulose derivative is methylcellulose derivative. 
     
     
         32 . The method of  claim 30 , wherein said cellulose derivative is a hydroxypropylcellulose derivative. 
     
     
         33 . The method of  claim 32 , wherein said hydroxypropylcellulose derivative is hydroxypropylcellulose partially substituted by allyl isocyanate. 
     
     
         34 . The method of any one of  claims 30  to  32 , wherein said cellulose derivative is partially substituted by a substituent that comprises a self-linkable group. 
     
     
         35 . The method of  claim 34 , wherein said self-crosslinkable group comprises an unsaturated double carbon-carbon bond. 
     
     
         36 . The method of  claim 34 , wherein said substituent comprises allyl isocyanate, methacrylic acid, acrylic acid, or glycidyl methacrylate. 
     
     
         37 . The method of any one of  claims 29  to  36 , wherein said polymer precursor is thermo-sensitive, and said inducing phase separation comprises heating said solution. 
     
     
         38 . The method of  claim 29 , wherein said polymer precursor is pH-sensitive, and said inducing phase separation comprises changing pH of said solution. 
     
     
         39 . The method of any one of  claims 29  to  38 , wherein said crosslinking comprises irradiating said emulsion with γ-ray. 
     
     
         40 . The method of any one of  claims 29  to  39 , wherein said polymer is a gel.

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