B

IOMATERIALS

L

AB

N ETWORK D EGRADATION Monday, February 6

th

and Tuesday, February 7

th

P RE-LAB

 

Sign-in Quiz

(Metters. 2000)

Rectangular Approximation

"Approximating the Area Under a Curve for AP Calculus | Education.com."

Education.com | An Education & Child Development Site for Parents | Parenting & Educational Resource

. Web. 06 Feb. 2012. .

Procedural Notes



Teamwork

 Take turns pipetting, massing, ect. but make sure you remember what has been added to the solution 

Pipetting

 Check the volume, change by twisting dial    When filling, go to first stop When ejecting precursors, go to second stop When ejecting into syringe mold, go to first stop (to avoid bubbles)

L INEAR M OLECULES



PEG-PLA-MA



MSA MAA

(CH 2 ) 4

M

ETHACRYLATE

P

OLYMERIZATION

Step-growth Polymerization …… 1 “Arm” PEG PLA MA Unlike last lab, each double bond can hook up with TWO other molecules.

(Lin, C.C.,

Pharmaceutical Research

. 26(3): 631-643. 2009)

S ECTION 1

PEG-PLA-MA Network Synthesis

  Can surmise from

Metters.2000

this will be bulk degrading Monitor change in network over time…     Size (diameter / height) Weight Young’s Modulus Stereo-microscopy Imaging Polyanhydrides.

Wikipedia

. 2011

PEG N ETWORK S YNTHESIS

1.

10wt% PEG-PLA-MA in PBS 2.

3.

 10% photo-initiator by volume (LAP) 40μL placed in 1mL syringe (tip cut off) to create cylindrical hydrogel sample geometry 4.

5.

exposed to UV-lamp for 10min Remove and place in PBS 6.

3 PEG samples

S ECTION 2

MSA/MAA Network Synthesis

  Glassy polymer Monitor change in network over time…     Size (diameter / height) Weight Young’s Modulus Stereo-microscopy Imaging Polyanhydrides.

Wikipedia

. 2011 (CH 2 ) 4

MSA/MAA N ETWORK S YNTHESIS

1.

2.

3.

4.

5.

Unlike PEG-PLA-MA, the MSA/MAA is a bulk reaction that is not polymerized in a liquid phase. ≈0.25g of MSA/MAA 0.1wt% DMAP photo-initiator added to PA-MA Fill mold “sandwich” (glass slide / Teflon / glass slide) exposed to UV-lamp for 10min Remove and place in PBS 6.

1 MSA/MAA sample

T ESTING

     Young’s modulus in Materials Testing Lab – 5N load cell Mass – after patting networks dry Size – use calipers for height and diameter. Don’t squish hydrogel  All three will be assembled and posted on blackboard.

Stereo-microscopy Imaging – collect images with digital camera  Each group is responsible for collecting their own images All performed on D0, D1, D3, D8, D10

   

Big Picture

Control of mechanical properties & degradation behavior allows tuning to your application  Ex: Control degradation rate  Control drug release rate Bulk   Typically hydrophilic  Biologically inert Large number of available chemistries Surface   Typically hydrophobic  Protein adsorption, cell interaction Constant turnover at surface  difficult to integrate with tissue Applications  Prevent postsurgical adhesion formation  In vivo drug and protein delivery   Temporary scaffold for tissue repair Degradable sutures

S ECTION 3

Degradation time-course

  Look at how networks degrade over time 1 team member per data collection day

D AY

0 1 3 8 10

Monday’s Lab

Monday, February 6 th (in lab) Tuesday, February 7 th Thursday, February 9 th Tuesday, February 14 nd Thursday, February 16 th

Tuesday’s Lab

Tuesday, February 7 th (in lab) Wednesday, February 8 th Friday, February 10 th Wednesday, February 15 th Friday, February 17 th