Background:
RADA-4 (Ac-RADARADARADARADA-NH2) is the most extensively
studied and marketed self-assembling peptide, forming hydrogel, used to create defined threedimensional
microenvironments for cell culture applications.
Objectives:
In this work, we use various biophysical techniques to investigate the length
dependency of RADA aggregation and assembly.
Methods:
We synthesized a series of RADA-N peptides, N ranging from 1 to 4, resulting in four
peptides having 4, 8, 12, and 16 amino acids in their sequence. Through a combination of various
biophysical methods including thioflavin T fluorescence assay, static right angle light scattering
assay, Dynamic Light Scattering (DLS), electron microscopy, CD, and IR spectroscopy, we have
examined the role of chain-length on the self-assembly of RADA peptide.
Results:
Our observations show that the aggregation of ionic, charge-complementary RADA motifcontaining
peptides is length-dependent, with N less than 3 are not forming spontaneous selfassemblies.
Conclusion:
The six biophysical experiments discussed in this paper validate the significance of
chain-length on the epitaxial growth of RADA peptide self-assembly.