Glycine-spacers influence functional motifs exposure and self-assembling propensity of functionalized substrates tailored for neural stem cell cultures

Abstract

The understanding of phenomena involved in the self-assembling of bio-inspired biomaterials acting as three-dimensional scaffolds for regenerative medicine applications is a necessary step to develop effective therapies in neural tissue engineering. We investigated the self-assembled nanostructures of functionalized peptides featuring four, two or no glycine-spacers between the self-assembly sequence RADA16-I and the functional biological motif PFSSTKT. The effectiveness of their biological functionalization was assessed via in vitro experiments with neural stem cells (NSCs) and their molecular assembly was elucidated via atomic force microscopy, Raman and Fourier Transform Infrared spectroscopy. We demonstrated that glycine-spacers play a crucial role in the scaffold stability and in the exposure of the functional motifs. In particular, a glycine-spacer of four residues leads to a more stable nanostructure and to an improved exposure of the functional motif. Accordingly, the longer spacer of glycines, the more effective is the functional motif in both eliciting NSCs adhesion, improving their viability and increasing their differentiation. Therefore, optimized designing strategies of functionalized biomaterials may open, in the near future, new therapies in tissue engineering and regenerative medicine.

Towards Developing Bioresponsive, Self-Assembled Peptide Materials: Dynamic Morphology and Fractal Nature of Nanostructured Matrices

“…showed that by increasingly adding glycines spacers to SAPs, the behaviours of selfassembly and other peptides were better segregated [37]. Glutamine may affect the electrostatic interaction associated with self-assembly, however hydrophobic interactions have been determined by Kabiri to be dominant in (RADA)4 self-assembly [38].…”

“…GGGPQG, A and Q are shared between peptides. Glycines have no variable side chains, and are often used as spacers in synthetic peptide combinations [37]. Present in the both CPs, they may attenuate the bundling due to CP residues on, and are not likely altering, the morphology of (RADA)4.…”

3D culture of adult mouse neural stem cells within functionalized self-assembling peptide scaffolds

“…25,39 We demonstrated how the hydrophilic-hydrophobic balance of the inserted functional motifs may influence the β-sheet formation propensity of the SAPs. Indeed functional motifs comprising clustered hydrophobic residues can cause hydrophobic collapse of the monomers, preventing their assembling into β-sheets, and, on the other hand, in the case of too many hydrophilic residues, the overall double-layered structure of RADA16-I could be destabilized.…”

Comparing the Effectiveness of TAT and Myristoylation of gp91ds on Leukocyte Superoxide (SO) Release

“…It is well known that adding myristic acid or a tat carrier peptide to native peptides facilitates cell membrane permeability which is required for effectively targeting intracellular substrates. The addition of a glycine-glycine (gg) spacer between the tat and cargo portion of the peptide is reported to facilitate delivery of the cargo sequence (i.e., CSTRIRRQL) [3,4] (Figure 3). …”