Study On Self-assembly Of Functional Peptide Hydrogel And Its Application In Neural Regeneration

RADA16-I?Ac-?RADA?₄-CONH₂?is a widely investigated self-assembling peptide?Self-assembling peptide,SAP?.It can undergo ordered self-assembly to form stable secondary structures,thereby further forming a nanofiber hydrogel.The biological function can be obtained by linking functional amino acid sequences at the RADA16-I end,thereby expanding its scope of application.However,only a few fundamental reports are available on the influences of the peptide motifs on self-assembly mechanisms of designer functional RADA16-I SAP.In this paper,we design RGD-modified RADA16-I SAPs with a series of net charges and amphiphilicities.At the same time,growth factors are loaded on peptides with different charges under neutral conditions.The application of peptide loading growth factors is conducted on nerve regeneration.The details are as follow:1.The assembly/reassembly of these functionally designer SAPs are thoroughly studied using Raman spectroscopy,CD spectroscopy,and AFM.The nanofiber morphology and the secondary structure largely depend on the balance between the hydrophobic effects versus like-charge repulsions of the motifs,which should be to the focus in order to achieve a tailored nanostructure.Our study would contribute insight into considerations for sophisticated design of SAPs for biomedical applications.2.Different charge growth factors are loaded on RADA16-IKVAV and RADA16-RGD peptide hydrogels which have different charge under neutral conditions.We examine the release rate after each gel was loaded with growth factors.At the same time,an in vivo spinal cord injury model is constructed to examine the nerve regeneration at the site of injury at two weeks and two months after surgery.It has been found that the charge and fiber density of peptides can affect the release rate of different charge growth factors.And our materials eventually have a sustained release effect on the release of growth factors.At the same time,the mixed hydrogel of RADA16-IKVAV and RADA16-RGD loading growth factors can promote the regeneration of axon fibers and repair spinal cord injury.