Low tensile strength but extremely high elongation
Slow rate degradation, high permeability to many drugs and non-toxicity
Long-term drug/vaccine delivery devices
A copolymer of ε -caprolactone with glycolide, as a monofilament suture (Monacryl)
Other Polymers under Development
Low-cost biodegradable polyemer
Synthesis of polymers using microorganism
Polyhydroxybutyrate (PHB) & polyhydroxyvalerate (PHV), commercially available as a copolymer named Biopol
Require enzymes for biodegradation
Under consideration for several biomedical application
Synthetic poly(amino acids)
Wide occurrence in nature
High crystalline: difficult to process and slow degradation
Synthesizing “pseudo” poly(amino acids) using tyrosine derivative
Enzymatic attack and metabolization of the fragments occur
Resulting in a rapid loss of polymer mass, this type of degradation is also called “ bulk erosion ”
Simple chemical hydrolysis of the hydrolytically unstable backbone
Water penetrates the bulk of the device, attacking the chemical bonds
Reduction in molecular weight &the physical properties
Polymer penetrates the device, slower than the rate of conversion of the polymer into water-soluble materials.
Results in the device thinning over time while maintaining its bulk integrity.
Related factors that resulting degradation:
The presence of catalyst, additives, impurities.
The geometry of the device
the presence of moisture can degrade the biodegradable polymers
The polymers are quickly packaged after manufacture
Double-bagged, under an inert atmosphere or vacuum
Placing the device in a moisture proof container
Biodegradable polymer is sterilized by gamma or E-beam irradiation or Ethylene Oxide (EtO) gas
Temperature and humidity should be considered
“ Biomimetic calcium phosphate coating on electrospun- poly( ε -caprolactone) scaffolds for bone tissue engineering”
PCL scaffolds with uniform fibrous structure were fabricated by electrospinning.
Before CaP coating, a plasma surface treatment was applied to clean and activate the PCL surface for calcium and phosphate ion grafting.
The treated PCL scaffolds were immersed in 10× simulated body fluid (SBF10) for varying time periods.
By: F. Yang, J.G.C. Wolke, J.A. Jansen
The deposited calcium phosphate coatings improved the wettability of the electrospun PCL scaffold.
As the mineralized electrospun scaffold has a similar structure as the natural bone, it is expected to be a potential cell carrier in bone tissue engineering.
Scanning Electron Microscopy (SEM)
Energy Dispersive Spectroscopy
Water wettability test
Appendix a. Properties of common biodegradable polymers Polymer Melting Point (°C) Glass-Transition Temp (°C) Modulus (Gpa) a Degradation Time (months) b PGA 225—230 35—40 7.0 6 to 12 PLLA 173—178 60—65 2.7 >24 DLLA Amorphous 55—60 1.9 12 to 16 PCL 58—63 (—65)— (—60) 0.4 >24 PDO N/A (—10)— 0 1.5 6 to 12 PGA-TMC N/A N/A 2.4 6 to 12 85/15 DLPLG Amorphous 50—55 2.0 5 to 6 75/25 DLPLG Amorphous 50—55 2.0 4 to 5 65/35 DLPLG Amorphous 45—50 2.0 3 to 4 50/50 DLPLG Amorphous 45—50 2.0 1 to 2 a Tensile or flexural modulus. b Time to complete mass loss. Rate also depends on part geometry.
Appendix b. Commercial biodegradable medical products Application Trade Name Composition a Manufacturer Dexon PGA Davis and Geck Maxon PGA-TMC Davis and Geck Vicryl PGA-LPLA Ethicon Sutures Monocryl PGA-PCL Ethicon PDS PDO Ethicon Polysorb PGA-LPLA U.S. Surgical Biosyn PDO-PGA-TMC U.S. Surgical PGA Suture PGA Lukens Sysorb DLPLA Synos Endofix PGA-TMC or LPLA Acufex Arthrex LPLA Arthrex Interference screws Bioscrew LPLA Linvatec Phusiline LPLA-DLPLA Phusis Biologically Quiet PGA-DLPLA Instrument Makar Suture anchor Bio-Statak LPLA Zimmer Suretac PGA-TMC Acufex Anastomosis clip Lactasorb LPLA Davis and Geck Anastomosis ring Valtrac PGA Davis and Geck Dental Drilac DLPLA THM Biomedical Angioplastic plug Angioseal PGA-DLPLA AHP Screw SmartScrew LPLA Bionx Pins and rods Biofix LPLA or PGA Bionx Resor-Pin LPLA-DLPLA Geistlich Tack SmartTack LPLA Bionx Plates, mesh, screws LactoSorb PGA-LPLA Lorenz
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