140 likes | 248 Views
Protein Enhanced Bone Recovery. By Amanda Walker Working with Ashley Aston Weiner Mentored by Prasad Shastri. Analysis- Primary Objective. Main goal- to optimize protein release from a bone repair biopolymer Goal components minimize burst effect by optimizing porosity
E N D
Protein Enhanced Bone Recovery By Amanda Walker Working with Ashley Aston Weiner Mentored by Prasad Shastri
Analysis- Primary Objective • Main goal- to optimize protein release from a bone repair biopolymer • Goal components • minimize burst effect by optimizing porosity • Obtain a linear release of protein over 3 to 4 weeks (life span of polymer) • Factors to vary • Porogen material • Porogen concentration • Size of gelatin microspheres http://www.oplin.org/point/ http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T3D-438BNXR-1&_coverDate=06%2F15%2F2001&_alid=368044133&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=4944&_sort=d&view=c&_acct=C000006878&_version=1&_urlVersion=0&_userid=86629&md5=d5be4d79321979caf317181be7c98482
Analysis- Problem Statement • The data we have for the porosity effects are not sufficient. • Porogens mixed into polymer control protein release. • Previous protein release studies done from linear polymers. http://members.tripod.com/sunfh/pol6.gif
Analysis- Polymer explanation How does it work? • Polyanhydride degrades over the course of a month • Porogens quickly dissolve creating holes • Exposes proteins • Proteins are growth factors • Bone grows in as material degrades http://www.synergizedsolutions.com/simpsons/pictures/bart/scientist.gif http://www.nrc-cnrc.gc.ca/education/images/science/photos/victoria_02.jpg
Market Analysis • The market • Broken bones • 3 femur fractures per 10,000 population annually for young and old people • Bone disease • 50% of women 50+ have fractures related to osteoporosis • Spinal fusion • 290,000 surgeries in 2003 http://www.drrathresearch.org/clinical_studies/condition_bonefracture_print.html http://www.paralumun.com/osteoporosisstats.htm http://www.aaos.org/wordhtml/research/stats/spinefusion_recent.htm
Market Analysis • Competition • ETEX corporation • Endothermic curing takes 15-20 minutes • No proteins • NovaBone • Molds to shape of injury, but not immediately • Benefits over competition • Less invasive • More comfortable • Custom fit • Instant curing • Enhancement by growth factors • Crosslinking=material strength http://www.etexcorp.com/etex/content/products/index.shtml http://www.novabone.com/prod03.htm
Analysis- Background • Precedent- BCNU release study • Wafer placed in hole after glioblastoma removal • Release of BCNU kills leftover cancer cells • Improves lifespan • This device is currently being used in medicine. • Several other papers were researched. http://www.neuropat.dote.hu/jpeg/tumor/3gliobl1.jpg
Analysis- Material Components + Porogens and Proteins • Monomers • MSA • MCPH • Porogen • Salt • Gelatin • Protein/sugar • HRP as test protein • Crosslinking initiator MCPH + MSA Photoinitiator/ Blue light Crosslinked polymer
Analysis- Polymerization • Initiator= camphorquinone • Forms free radicals when exposed to blue light • By hydrogen atom extraction • Radicals initiate crosslinking http://www.bonartmed.com/upload/product/1/1096423878014_0.JPG http://www3.interscience.wiley.com/cgi-bin/abstract/109792870/ABSTRACT?CRETRY=1&SRETRY=0
Synthesis of Samples- Block Diagram Mix protein and sugar Coomassie assay Granulate protein Mix monomers, protein, and porogen Make and/or quantify porogen Add initiator Mold and expose
Hypothesis- Performance Metrics How will improvement be measured? • Polymerized samples will be degraded in 37 degree PBS. • PBS will be changed daily. • The old PBS will be analyzed using a protein quantification assay. • This will determine how much protein was released over the last time period.
Analysis- Performance Criteria • Constraints • Release=3-4 weeks • Avoid burst effect • Limitations • Time- 4 months • Money- no real constraints • Exclusions- some porogens • FITC-dextran, for example • BSA as a protein- too much background in negative controls Burst Effect
Validation- Current Status • Accomplished: • Protein uniformity verification • Protein quantification • Protein and porogen granulation • Made the cylindrical samples for the first porogen (NaCl) • Current work • Had to change the protein used from BSA to horseradish peroxidase (HRP) • Due to this we are using a different assay to quantify release in the degradation studies • The Coomassie assay was still used for protein uniformity verification • Degradation study of the NaCl porogen samples • Slightly delayed (about 2 weeks) due to the necessity of changing the protein