Lecture 8 - Fibrous Scaffold Fabrication Flashcards

1
Q

Fabrication of Natural Polymer-Based Nanofibers

A
  • Electrospun scaffolds usually crosslinked to improve stability (against water/enzymes) and to improve mechanical properties
  • Solvents could denature polymer (lose bioactivity)
  • Polymer goes through high voltage (20-25kV) which could change microstructure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Fabrication of Synthetic Polymer-Based Nanofibers

A

Can electrospin almost any synthetic polymer based on solvent combine with

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Electrospinning Gelatin

A
  • Gelatin dissolved at various concentrations in HFIP
  • Control diameter by concentration
  • Increase concentration, increase diameter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Disadvantage of Electrospun Nanofibrous Scaffold

A
  • Densely arranged architecture of fibers and accompanying small pores hinders efficient cellular infiltration and also prevents 3D cellular integration with host tissue in vivo after implantation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Salt Leaching

A
  • Use tube surrounding electrospinning needle to incorporate NaCl particles into electrospun nanofibers via gravity at specific intervals
  • Layer-by-layer nanofiber constructs containing tiny salt particles were mechanically compressed and molded into desirable 3D shapes
  • Required gentle ‘sintering’ to maintain strength upon aqueous exposure
  • Pores not perfectly distributed
  • Leach out salt with water, leaves sufficient pore size for cells to come in
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Cryogenic Electrospinning

A
  • Uses ice crystals as part of electrospinning collection device
  • Electrospun fibers collected onto ice crystals formed on surface of chilled ground drum within hollow cavity enabling loading/flowing of cooling material such as dry ice or liquid nitrogen
  • After drying, ice particles removed and micron-sized pores or voids remain between fibers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Sacrificial Fiber

A
  • PCL and poly(ethylene oxide) were co-electrospun to form dual polymer composite fiber aligned scaffold
  • PEO dissolved to obtain scaffold having larger pores
  • Pore size controlled by PEO fiber diameter and density
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

‘Wet’ Electrospinning

A
  • Liquid reservoir collector such as coagulation bath
  • Electrospun nanofibers spraying toward bath loop on top of liquid surface and then dispersed in bath and deposited onto metal electrode at bottom
  • Makes foam like structure
  • Highly porous sponge is formed following freeze drying
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Femtosecond Laser Irradiation

A
  • Laser with high intensity and ultrafast irradiance pulsed onto target surface containing electrospun fibers
  • Ultrafast heating, melting, and ablation of fibers induced by high laser energy can produce voids in fibers
  • Desirable geometric patterns such as grooves or matrix pores fabricated by controlling process parameters such as laser power, pulse, scanning rate, and orientation
  • Melting of remaining fibers eliminated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

UV Irradiation

A
  • Use photolithography through one porous mask to fabricate a microporous patterned nanofiber structure
  • Shallow holes etched into nanofibrous mesh beneath porous mask due to UV induced fiber degradation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Combining Nanofiber and Microfibers

A
  • Electrospun nanofibers have small pore size, hot melt extruded microfibers exhibit relatively larger pore size
  • Combining into composites overcomes electrospun nanofiber shortcomings
  • Electrospin nanofibers on top of existing microfiber layer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Electric Field Controlled Deposition

A
  • Varying electrode configurations to form specific electric field distribution can control deposition of electrospinning jet
  • Auxiliary parallel electrodes applied to fabricate aligned electrospun nanofibers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Overcoming Porosity Issues

A

Simultaneous electrospin fiber and electrospray cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly