Using  the  sweep  and  intersect  method  we  were  able  to  create  scaffolds  within   the   desired   size   constraints   of   8-­‐10mm   in   diameter,   8-­‐10mm   in  height,  and  0.2-­‐0.4mm  in  pore  diameter.    The  peg  design  seen  in  Figure  1b  in  the  methods  secBon  was  successful  in  keeping  most  of  the  force  off  the  Agarose  layer.    The  peg  design  with  the  Agarose  layer  has  not  been  empirically  tested  with  the  force  necessary  to  insert  the  scaffold  into  the  subjects  body  yet;  that  is  a  goal  for  the  remainder  of  the  program.    

1.  Create  cylinders  in  AutoCAD®  and  successfully  print  •  Using  a   sweep  paKern   [figure  1a]  we  were  able   to   create  a   laOce-­‐

like  structure  [figure  1c]  that  was  then  layered  to  create  the  desired  height   of   the   scaffold.     Once   this   was   complete   the   intersect  command   was   then   used   to   create   scaffold   with   interconnecBng  pores.  

2.  Test  different  structural  designs’  abiliBes  to  keep  Agarose  on  when  force  is  applied  •  We  experimented  with   different  ways   to   disperse   the   force   that   is  

applied  when  inserBng  the  scaffold  into  the  subjects  body.  •  Figure  1b  is  the  “Peg”  design  we  devised  so  that  the  pegs  rise  2mm  

above   the   Agarose   layer   so   the   force   is   directly   to   the   scaffold  instead  of  the  Agarose  layer.  

 

 3.  Create  PCL  (Polycaprolactone)  filament  and  get  to  print  without  breaking  

•  Use   the  polycaprolactone  pellets   and  a  filament  extruder   to   create  the  tubular  filament  necessary  for  the  3D  printer.  

•  Part  of  future  work    4.  Test  Strength  of  PCL  printed  parts  

•  Use  various  stress  and  strength  tests  to  determine  if  the  scaffold  design  can  handle  the  forces  of  everyday  wear  and  tear  in  the  subjects  body  

•  Part  of  future  work  5.  Culture  Stem  cells  on  printed  gra[  

•  Culture  subjects  stem  cells  on  the  matrix  of  pores   in  the  scaffold  to  see   if   the   it   will   allow   for   the   healthy   growth   of   both   bone   and  carBlage  cells  

•  Part  of  future  work  (veterinary  laboratory)  6.  Test  on  sheep  and  dogs  

•  Once  all  the  previous  steps  and  tests  are  successfully  completed,  the  scaffolds  must  then  be  tested  in  live  subjects  to  see  if  they  complete  the   goal   of   regeneraBng   healthy   new   bone   and   carBlage   when  replacing  damaged  bone  and  carBlage.  

The  use  of  bone  gra[s  in  veterinary  medicine  is  a  procedure  used  for  treatment  of  various  types  of  bone  injuries  and  joint  damage.    Through  veterinary  literature,  it  has  become  apparent   that  bone  gra[ing  has  been  a  part  of  discussions   since  the   early   1940’s  when   orthopedic   veterinary  medicine  was   first   being   thought  about.     [1]    A  bone  gra[   is  a   transplant  of  healthy  bone   in  replace  of  damaged  bone.    This  transplant  can  occur   in  the  form  of  an  allogra[  or  an  autogra[.    An  allogra[  is  when  the  bone  is  harvested  from  a  cadaver,  and  an  autogra[  refers  to  bone   harvested   from   the   paBent’s   body.   [2]     While   these   processes   do   help  restore  healthy  bone  and  carBlage  to  the  injured  areas,  both  methods  have  their  disadvantages.     Autogra[ing   is   the  more   favorable   of   the   two   because   it   uses  your  body’s  own  Bssue  and   thus   reduces   the   risk  of   gra[   rejecBon.    However,  this  method   requires   extended   surgical   Bme,   and   causes   increased   pain   at   the  harvesBng   site   and   the   potenBal   for   nerve   damage   at   the   harvesBng   site    Allogra[s   require   less   surgical   Bme   and   can   reduce   the   amount   of   pain   by  eliminaBng  the  harvesBng  site.    However,  they  do  have  a  greater  risk  of  rejecBon,  infecBon,  or  gra[  morbidity.    AddiBonally,  allogra[s  increase  the  cost,  are  not  as  readily  available  and  in  some  cases  they  take  longer  to  fully  heal.  [3-­‐4]    UlBmately  these   two   methods   can   be   superior   to   total   joint   replacements,   especially   in  younger  more  acBve  subjects.    Joint  replacement  surgeries  are  o[en  used  in  older  paBents   to   repair   arthriBc   or   severely   damaged   joints.     While   this   generally  increases   the  overall  quality  of   life  and  decreases  previous   joint  pain,   there  are  many   limitaBons   and   possible   complicaBons   it   comes   with.     Most   joint  replacements   last   at   least   10   years  with   some  of   the   newer   ones   lasBng   20-­‐25  years.    Even  then,  with  conBnued  physical  acBviBes  it  can  cause  wear  and  tear  on  the  replacement  and  lead  to  having  to  have  a  new    replacement  put  in.    Joint  replacements  also  create  a    risk  for  blood  clots  in  paBents.  While  there  are  measures    taken  to  prevent  this,  it  is  sBll  a  large  risk  that  comes    with  the  process.    Generally  joint  replacements  are  a    last  resort  surgery  as  there  is  a  lot  of  Bme,  dedicaBon,    and  strain  that  comes  with  the  extensive  rehabilitaBon    process.  [5]    

3D  Prin(ng  Biodegradable  Scaffolds  for  Use    in  Regenera(ve  Bone  Gra:ing  Jessica  Bramhall1,  Samuel  Franklin2,  Alex  Squires1,  and  Zion  Tse1  

Abstract  

Autogra[s,   allogra[s   and   joint   replacements   are   the   current   methods   used   for  repairing   damaged   bone   and   carBlage   in   joints.     These   methods   are   extensive  procedures   which   cause   pain   and   present   post-­‐operaBve   limitaBons   such   as   the  inability  to  do  certain  physical  acBviBes.    Using  a  3D  printer  and  stem  cell  culturing,  it   is  believed  that  we  can  print  and  grow  healthy  new  bone  and  carBlage  to  repair  damaged  joints.    Through  the  use  of  AutoCAD®  (computer-­‐aided  design  so[ware),  we  have  designed  a  scaffold  that  meets  the  desired  size  restraints  and  successfully  prints   on   a   Solidoodle®   3D   printer.     This   scaffold   will   be   printed   and   used   for  strength  and  stress  tesBng,  cell  bondage  tesBng,  and  Bssue  growth  tesBng.    Upon  compleBon  of  these  tests  it  can  be  determined  if  this  method  of  bone  and  carBlage  regeneraBon  is  a  viable  opBon  for  paBents  with  degeneraBve  joint  condiBons.      

Introduc(on  

Aim   Results  

Summary    

Acknowledgements  

Methods  

1  -­‐  College  of  Engineering,  University  of  Georgia,  Athens,  GA,  United  States  2  -­‐  College  of  Veterinary  Medicine,  University  of  Georgia,  Athens,  GA,  United  States  

 

1.  Nunamker,  David  M.,  and  Frederic  W.  Rhinelander.  "Textbook  of  Small  Animal  Orthopaedics."  Textbook  of  Small  Animal  Orthopaedics.  J.B.  LippincoK  Company,  1985.  Web.  18  July  2014.    

2.  "Bone  Gra[s:  MedlinePlus."  U.S  Na;onal  Library  of  Medicine.  U.S.  NaBonal  Library  of  Medicine,  n.d.  Web.  18  July  2014.  3.  "Pros  and  Cons  of  Autogra[  or  Allogra[  Use  in  ACL  ReconstrucBon."  Desio  Sports  Medicine  RSS.  N.p.,  n.d.  Web.  18  July  2014.  4.  "Autogra[:  The  PaBent's  Own  Bone."  Spine-­‐health.  N.p.,  n.d.  Web.  18  July  2014.  5.  "Weighing  the  Pros  and  Cons  of  Knee  Replacement  Surgery:  Special  Reports."Johns  Hopkins  Health  Alerts.  N.p.,  n.d.  Web.  18  July  2014.  

References  

1.  Research  reported  in  this  publicaBon  was  supported  by  the  NaBonal  Science  FoundaBon  with  the  project  Btle  REU  Site:  Interdisciplinary  Research  Experiences  in  Nanotechnology  and  Biomedicine,  under  award  number  EEC-­‐1359095.  

2.  Dr.  Mao    3.  Dr.  Arnold  4.  Medical  RoboBcs  Lab  at  UGA  5.  Jason  Locklin  

HarvesBng  site  for  bone  gra[  

•  Create  biodegradable  scaffolds  that  can  be  used  for  stress  tesBng,  cell  bondage  tesBng,  and  Bssue  growth  tesBng.  

 •  Develop   a   structural   design   that   will   keep   Agarose,   a   hydrophilic   material,  

aKached  to  Polycaprolactone  (PCL),  a  hydrophobic  material,  while  the  necessary  force  for  inserBon  is  exerted  onto  the  scaffold.    

Figure  1a   Figure  1c  Figure  1b  

UGA  

(Le[)  Final  printed  peg  scaffold  (Top  Le[)  Side  view  of  sweep  method   scaffold   with   8.4mm   height,   10mm   diameter   and  0.6mm   pore   (Top   Right)   Top   view   of   scaffold   with   0.6mm  pore   (red   box)   (Right)   Final   printed   peg   scaffold   with  approximately  a  2mm  layer  of  Agarose  on  top  

In  an  aKempt  to  find  a  different  method  for  repairing  damaged  bone  and  carBlage   in   joints   we   have   used   3D   prinBng   to   create   biodegradable  scaffolds  that  can  then  be  used  for  bone  and  carBlage  gra[ing.  Using  the  sweep  method,  we  were  able  to  create  a  scaffold  that  is  8.4mm  tall,  10mm  in   diameter,   with   0.6mm   pores   and   a   taper   of   4°.     QualitaBvely,   the  scaffold  holds  up  well  when  force  is  applied  to  it,  and  quanBtaBve  tesBng  is  planned  to  support  the  results.    Further  strength  and  stress  tesBng  will  be   conducted   on   the   scaffold   in   the   future   once   it   is   printed   with   the  biodegradable  material.    The  peg  design  in  Figure  1b  successfully  molded  with  the  Agarose  when  placed   in  the  well  with   it.    The  producBon  of  the  polycaprolactone   (PCL)   filament   and   prinBng   the   scaffolds   using   this  material  are  the  next  tasks  in  line.    Once  the  scaffold  is  successfully  printed  with  PCL,   full   strength   and   stress   tesBng   can  be   conducted   and   the  final  steps  in  the  method  secBon  can  be  carried  out.    These  tests  will  determine  if   3D   prinBng   biodegradable   scaffolds   for   use   in   joint   repair   is   a   viable  opBon  for  subjects  with  degeneraBve  joint  condiBons.    If  this  is  successful  the  same  process  could  then  be  used  for   joint  replacements.    This  would  eliminate   the   use   of   plasBcs   and   metals   in   the   subject   and   provide   the  ability  to  grow  a  healthy  new  joint.        

Figure  2d  

Figure  2c  

Figure  2a  

Figure  2b