Search Results (3)

Double network (DN) hydrogels composed of self-assembling low-molecular-weight gelators and a hybrid polymer network are of particular interest for many emerging biomedical applications, such as tissue regeneration and drug delivery. The major benefits of these structures are their distinct mechanical properties as well as their ability to mimic the hierarchical features of the extracellular matrix. Herein, we describe a hybrid synthetic/natural polymer gel that acts as the initial network based on sodium alginate and a copolymer, namely poly(itaconic anhydride-co-3,9-divinyl-2,4,8,10-tetraoxaspiro (5,5) undecane). The addition of amino acids and peptide-derived hydrogelators, such as Fmoc-Lys-Fmoc-OH and Fmoc-Gly-Gly-Gly-OH, to the already-made network gives rise to DNs crosslinked via non-covalent interactions. Fourier transform infrared spectroscopy (FTIR) and thermal analysis confirmed the formation of the DN and highlighted the interactions between the two component networks. Swelling studies revealed that the materials have an excellent water absorption capacity and can be classified as superabsorbent gels. The rheological properties were systematically investigated in response to different variables and showed that the prepared materials present injectability and a self-healing ability. SEM analysis revealed a morphology consisting of a highly porous and interconnected fibrous network. Finally, the biocompatibility was evaluated using the MTT assay on dermal fibroblasts, and the results indicated that the new structures are non-toxic and potentially useful for biomedical applications. Full article

In this paper, we described the synthesis procedure of TiO₂@SiO₂ core-shell modified with 3-(aminopropyl)trimethoxysilane (APTMS). The chemical attachment of Fmoc–glycine (Fmoc–Gly–OH) at the surface of the core-shell structure was performed to determine the amount of active amino groups on the basis of the amount of Fmoc group calculation. We characterized nanostructures using various methods: transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) to confirm the modification effectiveness. The ultraviolet-visible spectroscopy (UV-vis) measurement was adopted for the quantitative determination of amino groups present on the TiO₂@SiO₂ core-shell surface by determination of Fmoc substitution. The nanomaterials were functionalized by Fmoc–Gly–OH and then the fluorenylmethyloxycarbonyl (Fmoc) group was cleaved using 20% (v/v) solution of piperidine in DMF. This reaction led to the formation of a dibenzofulvene–piperidine adduct enabling the estimation of free Fmoc groups by measurement the maximum absorption at 289 and 301 nm using UV-vis spectroscopy. The calculations of Fmoc loading on core-shell materials was performed using different molar absorption coefficient: 5800 and 6089 dm³ × mol⁻¹ × cm⁻¹ for λ = 289 nm and both 7800 and 8021 dm³ × mol⁻¹ × cm⁻¹ for λ = 301 nm. The obtained results indicate that amount of Fmoc groups present on TiO₂@SiO₂–(CH₂)₃–NH₂ was calculated at 6 to 9 µmol/g. Furthermore, all measurements were compared with Fmoc–Gly–OH used as the model sample. Full article

We have previously developed water-based microwave (MW)-assisted peptide synthesis using Fmoc-amino acid nanopaticles. It is an organic solvent-free, environmentally friendly method for peptide synthesis. Here we describe water-based MW-assisted solid-phase synthesis using Boc-amino acid nanoparticles. The microwave irradiation allowed rapid solid-phase reaction of nanoparticle reactants on the resin in water. We also demonstrated the syntheses of Leu-enkephalin, Tyr-Gly-Gly-Phe-Leu-OH, and difficult sequence model peptide, Val-Ala-Val-Ala-Gly-OH, using our water-based MW-assisted protocol with Boc-amino acid nanoparticles. Full article