1 / 12

B IOMATERIALS L AB M ATERIAL M ECHANICAL P ROPERTIES

B IOMATERIALS L AB M ATERIAL M ECHANICAL P ROPERTIES. Monday, January 23 rd & Tuesday, January 24 th. BME 245/445 – Lab 1. P RE-LAB. Sign-in Quiz (Engler. 2006). W EIGHT P ERCENT C ALCULATIONS. Wt % = (Mass Solute)/(Total Solution Mass) × 100%. Determine total mass solute

igor-hester
Download Presentation

B IOMATERIALS L AB M ATERIAL M ECHANICAL P ROPERTIES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. BIOMATERIALS LABMATERIALMECHANICAL PROPERTIES Monday, January 23rd & Tuesday, January 24th BME 245/445 – Lab 1

  2. PRE-LAB • Sign-in • Quiz (Engler. 2006)

  3. WEIGHT PERCENT CALCULATIONS Wt% = (Mass Solute)/(Total Solution Mass) × 100% • Determine total mass solute • Determine mass PEG • Determine mole ratio of PEG MOLECULE to Thiol MOLECULE, using number of reactive species each & molecular weight • Solve for mass/vol of each

  4. THIOL-NORBORNENE PRECURSORS • PEG-Norbornene: • 2kD-PEG • 10kD-PEG • 20kD-PEG • Thiol: • 2SH • 3SH • 4SH

  5. 10kD-PEG + 3SH 3SH 10kD-PEG formation of a cross-linked mesh network

  6. THIOL-ENE POLYMERIZATION 1 Arm PEG (n=56) Norbornene Fairbanks, B.D. Adv Mater. 2009

  7. SECTION 1 Influence of precursors on end-stage mechanics • Look at different PEG-thiol combinations, constant polymerization time • Measure young’s modulus of resulting network • Make connections between precursors and mechanics • Number of “arms” • Mesh size • Steric hindrance ?

  8. SECTION 2 Determine network growth mechanism • PEG10,000 3SH • Look at how network develops over time • Step-growth polymerization? • Chain-growth polymerization? • Network “interaction” is related to observed mechanics Step-Growth Polymerization. Wikipedia. 2011

  9. HYDROGEL SYNTHESIS • 10wt% PEG in DMSO (20wt% for 2kD-PEG) • solution is thoroughly mixed (solublize PEG) • 1:1 mole ratio of thiol-linker • 10% photo-initiator by volume • 40μL placed in 1mL syringe (tip cut off) • to create cylindrical hydrogel sample geometry • exposed to UV-lamp for 10min • hydrogel removed and placed in DMSO

  10. MECHANICAL TESTING • MTS system in Materials Testing Lab – 5N load cell “Benoit Lab Test” • cyclic compression at 5-10% elongation of gel height • 0.1mm/sec compression rate • Modulus calculated using 1-4% strain range (linear)

  11. SECTION 3 Investigate Tensile Properties & Fracture of Biomaterials • Load sample into PASCO stress/strain apparatus • Begin data collection, steadily turn handle to apply tension • Once bar breaks, stop data collection and remove sample • Export data to Excel for post-lab calculations • Expected vs. observed behavior for each material • Take image of fracture site using stereo microscope • Observed differences in fracture mechanics?

  12. Safety • General • Lab glasses, gloves, closed toed shoes • No food, no drinks, no applying makeup • Specific • DMSO: Eye, skin irritant; ingestion leads to nausea, vomiting, diarrhea, central nervous system damage • Thiols: Eye, skin, respiratory irritant; cause nausea, headache, vomiting; unpleasant smell • Use in HOOD!!!

More Related