Synthesis of poly(ε-caprolactone)-based polyurethane semi-interpenetrating polymer networks as scaffolds for skin tissue regeneration

A new biodegradable poly(ε-caprolactone)-polyurethane semi-interpenetrating polymer network (PCL-PU-semi-IPNs) was synthesized through the reaction of hydroxyl-terminated four-armed star-shaped PCL, 1,4-diisocyanatobutane, and ethylenediamine. Afterwards, the three-dimensional (3D) porous structure of the polymer was prepared through particulate leaching and freeze-drying methods. The chemical structure of star-shaped block PCL-PU polymer was confirmed by ¹H NMR and IR spectroscopy. The morphology of the fabricated PCL-PU-semi IPN scaffolds was identified by scanning electron microscopy. Results indicated that lower polymer concentration can lead to formation of an isolated pore with a small size, while increasing polymer concentration increases the pore size. Fibroblast cells culturing on the scaffold suggests that the fabricated PU-based scaffold is biocompatible and can be considered as a suitable scaffold material for skin tissue engineering applications.     

Synthesis of Prussian Blue Metal Coordination Polymer Nanocubes via Cyanoferrate Monomer Design

The effect of cyanoferrate monomers on the metal coordination polymerization of Fe³⁺ and [Fe(CN)₅L]^3?, where L = CN, NH₃, pyrazine (Pz), pyridine (Py) and 4-(dimethylamino)-pyridine (DMAP), for the synthesis of Prussian blue (PB) polymers was investigated. The polymerizations were performed in water at ambient temperature in the absence of templates and/or surfactants. The morphology and crystallinity of the resulting polymers are influenced by the nature of the ligands L associated with the monomers. When L = CN or NH₃, crystalline polymers with irregular structures were produced. The polymerization employing [Fe(CN)₅L]^3? with L = Pz, Py and DMAP led to amorphous polymers with a tendency to form individual nanoparticles depending on the choice of L. Notably, in the case of [Fe(CN)₅DMAP]^3?, amorphous PB nanocubes with a regular size distribution were produced. Based on this study, the binding forces of L to Fe(II)(CN)₅ is highlighted as an important parameter for PB metal coordination polymer nanostructure control and design.     

An Efficient and Green Synthesis of 1′Hspiro[isoindoline-1,2′-quinazoline]-3,4′(3′H)-dione Derivatives in the Presence of Nano Fe3O4–GO–SO3H

ABSTRACT

In this article a simple, rapid, green and efficient method for the synthesis of various 1′Hspiro[isoindoline-1,2′-quinazoline]-3,4′(3′H)-diones in the presence of acidic magnetic graphene oxide nanosheets (Fe₃O₄–GO–SO₃H) as catalyst is reported. Different substituted spirooxindoles have been synthesized from one-pot three component reaction of isatoic anhydride, aliphatic or aromatic primary amines and isatin in the presence of Fe₃O₄–GO–SO₃H. This reaction allowed us to prepare some new and known derivatives of substituted spirooxindoles. The worthwhile advantages of this method are high product yields, short reaction times, the possibility of using of a magnetic, reusable and non-toxic catalyst and solvent-free conditions.     

An aligned fibrous and thermosensitive hyaluronic acid-puramatrix interpenetrating polymer network hydrogel with mechanical properties adjusted for neural tissue

Journal of Materials Science - Central nervous system (CNS) injuries such as stroke or trauma can lead to long-lasting disability, and there is no currently accepted treatment to regenerate...     

Dual lanthanide role in the designed synthesis of hollow metal coordination (Prussian Blue analogue) nanocages with large internal cavity and mesoporous cage

Prussian Blue (PB) analogue metal coordination nanocages comprised of mesoporous walls (ca. 3.5 nm pore width) encapsulating a cavity approaching ca. 100 nm in diameter (surfactant free) are presented as an advance in rational metal coordination polymer nanostructure design. The synthesis employs lanthanide ions (Gd(3+) or Er(3+)) which function initially as peripheral coordination crosslinkers of metallo-surfactant templated miniemulsion droplets, and, subsequently, as promoters in the removal of the organic component of those surfactants via metal-assisted ester hydrolysis. The success of this synthetic strategy relies entirely on the periphery coordination event occurring prior to the ester hydrolysis surfactant removal step. Crucially, this one-pot sequential synthesis was achieved using a newly developed metallo-surfactant designed to have a reduced ester hydrolysis rate. Syntheses of this innovative metallo-surfactant, intermediary PB analogue coordination polymer organo-nanoshells and the subsequent conversion to hollow metal coordination nanocages are fully characterised using a wide variety of techniques, including TEM, SEM, EFTEM, EDX, TGA, WAXD, NMR, N(2) adsorption, etc., and represent the first designed synthesis of hollow metal coordination nanocages containing a large nanoscale cavity (wall of hollow nanosphere is mesoporous; hence nanocage).     

Novel methods to fabricate macroporous 3D carbon scaffolds and ordered surface mesopores on carbon filaments

New methods for fabrication of 3D macroporous carbon scaffolds and synthesis of mesopores on carbon surfaces are proposed. Ordered macroporous filamentary carbon structures were made by rapid prototyping using solvent-based extrusion freeforming which allows the scaffold to be designed on computer and downloaded directly to a building platform. The surface of extruded filaments was decorated with 20?C25?nm open mesopores by coating with nano-silica as a hard template followed by pyrolysis and dissolution of the silica. This left an open mesoporous surface to serve as a host for catalysts or enzymes while retaining integrity in the core for electrical and mechanical performance. The combination of these two methods could be used to make different hierarchical, multi-functional carbon structures which could be applied in fuel cells as the catalyst carrier and biofuel cell electrode.     

Design of biocompatible polylactic acid–polyethylene glycol combination for manufacturing biodegradable staplers

For the development of an effective and faster wound closure method, it is necessary to overcome current techniques' limitations. As compared to other methods, biodegradable staples provide superior mechanical properties, reduce scarring, and promote healing faster. Here, polylactic acid (PLA) and polyethylene glycol (PEG) composite staplers produced by solvent casting are presented as a suggestion for rapidly and easily closing wounds. The resulting samples were tested for mechanical properties, contact angle, and degradation properties over 21–90 days in the engineering phase. Selected formulations were moved to the biological phase for in vitro cytotoxicity by MTT assay and the in vivo biocompatibility assessment by transplantation of the samples into rats' back muscle. The tissue samples were collected and evaluated using hematoxylin and eosin and trichrome staining 1, 6, and 12 weeks after transplantation. When considering the maximum force tolerance range for PLA–PEG at around 20–58 N and comparing it with comparable commercial products, as well as their degradation rate and hydrophilicity, it was concluded that this combination maintains wound edges together. Cell viability tests demonstrated no cytotoxicity in the samples after 48 and 72 h. Morphological observations indicated some condensations of collagen fibers and no remarkable infiltration of inflammatory cells around the transplanted samples. In conclusion, the combination of PLA and PEG showed suitable mechanical properties, superior hydrophilicity, high biocompatibility and is suitable for medical staplers, and is innovative.