CHEN, Shaochen, 3d Bioprinting, Tissue Engineering, UCSD, May 29, 2018
<p class="MsoNormal" >CHEN, Shaochen, 3d Bioprinting, Tissue Engineering, UCSD, May 29, 2018
This is the 12:30PM weekly Tuesday, CVI lecture at Stanford in LKS 130.
<b>SC = Shaochen Chen </b>is a Prof. of Tissue Engr at UCSD (and director.)
(he has a YouTube similar to this talk from April 2018.)
he begins...
Regenerative Medicine: addresses many organ systems.
Tony Atala paper in Nature Biotech 2014: he cites.
many different levels of stiffness of tissues:
eg from (soft) fat to (hard) articular cartilage.
he reviews traditional 3d BioPrinting techniques:
eg drop by drop (via an inkjet)
or microextrusion (like toothpaste) line by line
but better is Laser stereolithography.... point by point
but it's slow.
his work (from 2006) scanningless 3d... using UV curable resin
layer by layer...
then from 2012: he shows printing of vasculatures....in seconds!
10 to 20 micron vessels.
(but see my Q to him: they have not yet perfused these.)
can pull out a growing structure from solution... to get
continuous optical printing of 3d scaffolds....
continuous... eliminates artificial interfaces between beads or lines.
we use uncrosslinked monomers; cells,
can capture them in a hydrogel scaffold.
and PEGDA Polyethylene glycol Diacrylate
Gelatin Methacrylate GelMA
Hyaluronic Acid and others.
nice contours in z direction.
next: the 3rd topic in his outline
embed PDA nanoparticles in the gel.
can use for detoxification.
can collect and sense toxins.
create a sponge like device...
3d printed artificial Micro-fish...
put them into H2O2.
fish size is 100 micron.
guide it with magnet.
and with iron oxide in head and platinum oxide in tail.
imagine the 1966 Fantasic Voyage movie written by Harry Kleiner.
topic four: regulating scaffolds:
stiffness: change crosslinking
Poisson's ratio = PR.
PPR = positive ratio...
like Chinese handcuffs (shrinks in diameter with stretching)
but we can design such that it expands (negative PR)
V (fifth topic)
3d bioprint of human liver model.
with central vein in each lobule.
looks like stained glass.
use hydrogel of GelMA.
and cells are hiPSCs-HPCs. human induced Pluripotent Stem Cells.
merge two layers
one with hiPSCs-HPCs (hepatic cells) and the other with HUVEC and ADSCs.
we get expression of four key liver-specific genes.
Albumin;
and TTR (transthyretin)
HNF4a and
AFP alphafetoprotein...
and get albumin secretion...
and can get induction of CYP from rifampin.
*
model of heart muscle on a cantilever.
similar to a rubber band around two posts.
shows beating of NMVCM tissue.
printing parallel lines => greatest displacement of posts. (most force)
shows endothelial network formation and they form
lumen-like structures.
Summary:
light based 3d printing offers microscale resolution and is 3000 times faster.
"Human on a chip.." eg for drug testing.
Chen Lab: at UC San Diego. BioNano.
(I chat with Prof. Jay Rajadas (who heads lab at Stfd: BioADD))
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