A Short Review on Bio-compatible/Bio-degradable| Photopolymers for Stereolithography Bio-3D Printing - Juniper publishers
Journal of Trends in Technical and Scientific Research
Abstract
One of the important procedures in Bio-3D printing is
to print/fabricate the scaffold for tissue engineering. A scaffold is a
porous biomedical implant, which provides a short-term support to
seeded cells in order to direct the formation of new tissues. The
scaffold must be non-toxic, biodegradable, biomechanical properties,
specific chemical composition and have a precisely defined pore size and
geometry. For this reason, it is very important to fabricate scaffolds
with high precision. In this review, 3D printing of biomedical scaffolds
using photo polymerization process is briefly reviewed. As per
requirements of tissue engineering, the choice of best 3d printing
method and photopolymer were discussed. Apart from this bio-3D printing
application, the bio-compatible photopolymer will be widely used in
dental application, like the direct printing of aligner in orthodontics
and temporary denture fabrication.
Keywords: Tissue Engineering; Bio-compatible; Photopolymers; Stereolithography
Abbreviations: FDM:
Fused Deposition Modelling; SLS: Selective Laser Sintering; 3DP: Three
Dimensional Printing; LS: Laser Stereolithography;
AM: Additive Manufacturing; DLP: Digital Light Projection; UV:
Ultra-Violet;SL: Stereolithography; PCL: Polycaprolactone; PCL-DA:
Polycaprolactone- Diacrylate; PGSA: Polyglycerol sebacate Acrylate
Introduction
In biomedical engineering, the tissue engineering is a
rapidly growing multidisciplinary research area to reconstruct organs
and tissues [1]
by using a biodegradable and biocompatible scaffolding structure. As
described early, it is very important to fabricate scaffolds with high
precision. The scaffold has been fabricated using various 3D printing
techniques such as FDM extrusion, SLS, 3DP. In these methods, the
smallest printable size is 50-200 |im which is too large to be used for
some biomedical implant or certain tissue engineering applications [2].
Stereolithography
LS is presently one ofthe most rapidly growing AM
technique widely used in different areas of science and technology,
engineering and biomedicine. LS is a polymerization process in which the
spatially controlled solidification of resin is achieved using various
types of laser radiations. The key benefit of using LS are high spatial
resolution (-0.1 mm), fast manufacturing speed, high precision and a
large variety of materials [3].
Commercially available LS 3D printers can print parts with an accuracy
of 20|im. A recently developed two-photon polymerization LS setup can
build micron-sized structures with sub-micron accuracy [4].
DLP is another emerging SL technique in which an
array of millions of independently rotatable mirrors is used to project
the light in order to polymerize photosensitive materials layer-
by-layer under the action of UV or visible light [5].
LS is one of the best choice to fabricate scaffolds with required size
and resolution but expensive. In a recent study, Jeng et al. [6] employed projection based SL technique and precisely printed biocompatible porous matrix structures for tissue engineering.
For 3D bio-printing of implants using Vat photo
polymerization technology, the biological material need to benon-toxic,
biocompatible and biodegradable photopolymer. Therefore, it is not easy
to develop photopolymers for scaffolds and medical related applications.
That's why they are rarely available commercially. There are
biocompatible/ biodegradable polymers available, but mostly are not
photo curable and need to be modified to make it photo curable. The
photopolymer changes its structural properties when exposed to light,
mostly cured by UV light. Photo polymeric materials consists of three
main components including monomers (long- chain molecules), Photo
initiators (split into radicals after energy input) and additives (UV
stabilisators) [7].
A very limited number of photo-curable biocompatible materials are
available for scaffold 3d printing. We are capable to describe only a
few of them.
Bio-Compatible Photopolymers
PCL is a semi-crystalline polymer of aliphatic
polyester group, which is a thermoplastic biodegradable material derived
from crude oil by ring opening polymerization. Due to excellent
biodegradability, high flexibility and biocompatibility, PCL is widely
used in biomedical implants. In 2002, Kweon et al. [8]
used PCL-diol with a molecular weight of 2000 for the preparation of
PCL-DA through a series of chemical reactions. At Massachusetts
Institute of Technology (MIT), another vital material PGSA was prepared
in 2007, which is based on a chemical change of PGS with acryl ate
moieties. Instead of PGS, PGSA is a rapidly cured material to form
polymeric networks at ambient temperature. In a most recent research,
Cheng et al. [9]
prepared a photo-curable scaffold material by mixing PCL-DA and PGSA
and concluded that the new material had improved mechanical properties
compared to individuals.
Conclusion
Though several AM techniques are used for bio-3DP
applications, Stereolithography setup can print porous
biocompatible/biodegradable scaffolds with required size, resolution and
surface finish. The bio-compatibility of the photopolymer is one of the
most concerns in this VAT process.
PCL and PGSA are photo-curable non-toxic materials
with excellent biocompatibility and mechanical properties, however, new
materials can be made by combining liquid acrylated polymer precursor
with other acrylated molecules for a number of potential biomedical
applications. Definitely, there will be more new bio-compatible
photopolymer material will be investigated to meet the application of
bio 3D Printing and even bio-medical device like dental application.
To Know More About Trends in Technical and ScientificResearch click on: https://juniperpublishers.com/ttsr/index.php
To Know More About Open Access Journals Please click on:
Comments
Post a Comment