Molecular Gels for Tissue Engineering - Soft Fibrillar Materials: Fabrication and Applications - page 153

conditions, molecular gels have outstanding bio-degradability. For example, molec-
ular gels containing cells for tissue regeneration can be designed to promote cell
growth initially, and then gradually degrade in a controlled manner by enzymatic
hydrolysis, so as to not interfere with cell differentiation at a later stage. In addi-
tion, self-assembly makes molecular gels clear of toxicity caused by cross-linking
initiation. The defined control over the physical and chemical properties of a
molecular gel for specific applications is another advantage. Peptide amphiphile is
an example of refined control over molecular gel gelation by altering and designing
the molecular structure of the gelators. The serendipity of the identification of
gelators has developed into syntheses and applications of a variety of peptides
for tissue regeneration. In contrast to natural polymer-based hydrogels such as
collagen and gelatin, the applications of saccharide-based molecular gel in tissue
engineering are only beginning to be realized, with huge potentials. While the
use of lipid-based molecular gels is still generally limited to targeted drug delivery
at the present time, some promising potentials for them to support cell growth
and adhesion have been successfully demonstrated. Nucleic acid and nucleobases
containing molecular gels, aside from tissue engineering, have also demonstrated
other new and exciting biomedical applications, such as cell-free protein expression
and controlled drug delivery. However, notwithstanding all the desirable properties
that molecular gels possess for the future of patient-tailored tissue engineering,
they are still restricted by the lack of suitable mechanical properties and the inability
to produce a mechanically dynamic environment of the kind that many tissues are
living in, and these pose challenges for future improvements to address.

List of Abbreviations

CAB -cholesteryl-4-(2-anthryl)butanoate

DC 8,9 PC Diacetylene-1,2-bis(tricosa-10,12-diynoyl)-sn-glycero-3-phosphocholine
EAK 16 Glutamic acid-alanine-lysine 16
ECM Extracellular matrix
GP-1 N -lauroyl- l -glutamic acid di- n -butylamide
HAS 12- Hydroxystearic acid
IKVAV

3- β

Isoleucine-lysine-valine-alanine-valine

LMWGs Low-molecular-weight gelators

MSC Mesenchymal stem cells

MTT 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide

P-gel Protein-producing gel

PS Phosphatidylserine

RAD Arginine-alanine-aspartic acid

RGD Arginine-glycine-aspartic acid

SAPNS Self-assembling peptide nano-fiber scaffold

S1P Sphingosine-1-phosphate