Browsing by Subject "Biomimetic materials"

Now showing 1 - 3 of 3

Open Access
Investigating the effects of bioactive peptide nanofibers on the growth and differentiation behaviour of nervous system cells
(2017-07) Yılmaz, Canelif
Peripheral nerve regeneration is a tightly regulated process that entails the degeneration, proliferation, alignment and remyelination of Schwann cells. Tuning the bioactivity is important to support all of these processes and achieving successful regeneration. Extracellular matrix (ECM) proteins are important molecules for controlling cell behavior and differentiation. Mimicking the natural ECM proteins is a promising approach for promoting regeneration in peripheral nerve injury. In this study, we investigated the biocompatibility and bioactivity of two natural ECM mimicking peptide amphiphile (PA) molecules, heparan sulfate-mimicking PA (HM-PA) and laminin-mimicking PA (LN-PA), and showed that they self-assemble into ECM-like nanofibrous networks. These bioactive nanofibers promote the viability, proliferation and spreading of Schwann cells, and that the combination of the two bioactive epitopes supports both early and late neuroregenerative responses of Schwann cells. We have also shown that these nanofibers support the attachment and neurite extension of dorsal root ganglion neurons, and promotes neurite alignment and assembly in DRG-Schwann cell co-cultures.
Open Access
Selective adhesion and growth of vascular endothelial cells on bioactive peptide nanofiber functionalized stainless steel surface
(Elsevier, 2011) Ceylan, Hakan; Tekinay, Ayse B.; Güler, Mustafa O.
Metal-based scaffolds such as stents are the most preferred treatment methods for coronary artery disease. However, impaired endothelialization on the luminal surface of the stents is a major limitation occasionally leading to catastrophic consequences in the long term. Coating the stent surface with relevant bioactive molecules is considered to aid in recovery of endothelium around the wound site. However, this strategy remains challenging due to restrictions in availability of proper bioactive signals that will selectively promote growth of endothelium and the lack of convenience for immobilization of such signaling molecules on the metal surface. In this study, we developed self-assembled peptide nanofibers that mimic the native endothelium extracellular matrix and that are securely immobilized on stainless steel surface through mussel-inspired adhesion mechanism. We synthesized Dopa-conjugated peptide amphiphile and REDV-conjugated peptide amphiphile that are self-assembled at physiological pH. We report that Dopa conjugation enabled nanofiber coating on stainless steel surface, which is the most widely used backbone of the current stents. REDV functionalization provided selective growth of endothelial cells on the stainless steel surface. Our results revealed that adhesion, spreading, viability and proliferation rate of vascular endothelial cells are remarkably enhanced on peptide nanofiber coated stainless steel surface compared to uncoated surface. On the other hand, although vascular smooth muscle cells exhibited comparable adhesion and spreading profile on peptide nanofibers, their viability and proliferation significantly decreased. Our design strategy for surface bio-functionalization created a favorable microenvironment to promote endothelial cell growth on stainless steel surface, thereby providing an efficient platform for bioactive stent development for long term treatment of cardiovascular diseases. © 2011 Elsevier Ltd.
Open Access
Self-assembled template-directed synthesis of one-dimensional silica and titania nanostructures
(2011) Acar H.; Garifullin, R.; Güler, Mustafa O.
Mineralized biological materials such as shells, skeleton, and teeth experience biomineralization. Biomimetic materials exploit the biomineralization process to form functional organic-inorganic hybrid nanostructures. In this work, we mimicked the biomineralization process by the de novo design of an amyloid-like peptide that self-assembles into nanofibers. Chemically active groups enhancing the affinity for metal ions were used to accumulate silicon and titanium precursors on the organic template. The self-assembly process and template effect were characterized by CD, FT-IR, UV-vis, fluorescence, rheology, TGA, SEM, and TEM. The self-assembled organic nanostructures were exploited as a template to form high-aspect-ratio 1-D silica and titania nanostructures by the addition of appropriate precursors. Herein, a new bottom-up approach was demonstrated to form silica and titania nanostructures that can yield wide opportunities to produce high-aspect-ratio inorganic nanostructures with high surface areas. The materials developed in this work have vast potential in the fields of catalysis and electronic materials. © 2011 American Chemical Society.