Conducting Cytocompatible Scaffolds: Composite of Sodium Hyaluronate and Colloidal Particles of Conducting Polymers

Novel bio-inspired conductive scaffolds composed of sodium hyaluronate containing water soluble polyaniline or polypyrrole colloidal particles (concentrations 0.108, 0.054 and 0.036 % w/w) were manufactured. For this purpose, either crosslinking with N-(3-dimethylaminopropyl-N-ethylcarbodiimide hydrochloride and N-hydroxysuccinimid or a freeze-thawing process in the presence of poly(vinylalcohol) were used. The scaffolds comprised interconnected pores with prevailing porosity values of ~30 % and pore sizes enabling the accommodation of cells. Good swelling capacity (92 – 97 %) without any sign of disintegration was typical for all samples. The elasticity modulus depended on the composition of the scaffolds, with the highest value of ~50 000 Pa obtained for the sample containing the highest content of polypyrrole particles. The scaffolds did not possess cytotoxicity and allowed cell adhesion and growth on the surface. Using the in vivo-mimicking conditions in a bioreactor, cells were also able to grow into the structure of the scaffolds. The technique of scaffold preparation used here thus overcomes the limitations of conducting polymers (e.g. poor solubility in an aqueous environment, and limited miscibility with other hydrophilic polymer matrices) and moreover leads to the preparation of cytocompatible scaffolds with potentially cell-instructive properties, which may be of advantage in the healing of damaged electro-sensitive tissues.

A General Method for Synthesis of Isomaleimide Derivatives

A mild and efficient method for the synthesis of isoimide by a simple reaction of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) with various kinds of maleimicacid, succimicacid, pthaleimicacid in dichloromethane at room temperature is described.

Eucommia ulmoides Leaf Polysaccharide in Conjugation with Ovalbumin Act as Delivery System Can Improve Immune Response

In this investigation, to maximize the desired immunoenhancement effects of PsEUL and stimulate an efficient humoral and cellular immune response against an antigen, PsEUL and the model antigen ovalbumin (OVA) were coupled using the N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) reaction to yield a novel delivery system (PsEUL-OVA). The physicochemical characteristics and immune regulation effects of this new system were investigated. We found the yield of this EDC method to be 46.25%. In vitro, PsEUL-OVA (200 μg mL−1) could enhance macrophage proliferation and increase their phagocytic efficiency. In vivo, PsEUL-OVA could significantly increase the levels of OVA-specific antibody (IgG, IgG1, IgG2a, and IgG2b) titers and cytokine (IL-2, IL-4, IL-6, IFN-γ) levels. Additionally, it could activate T lymphocytes and facilitate the maturation of dendritic cells (DCs). These findings collectively suggested that PsEUL-OVA induced humoral and cellular immune responses by promoting the phagocytic activity of macrophages and DCs. Taken together, these results revealed that PsEUL-OVA had the potential to improve immune responses and provide a promising theoretical basis for the design of a novel delivery system.

Effects of Hinokitiol and Dicalcium Phosphate on the Osteoconduction and Antibacterial Activity of Gelatin-Hyaluronic Acid Crosslinked Hydrogel Membrane In Vitro

Many hydrogel-based crosslinking membranes have been designed and tailored to meet the needs of different applications. The aim of this research is to design a bifunctional hydrogel membrane with antibacterial and osteoconducting properties to guide different tissues. The membrane uses gelatin and hyaluronic acid as the main structure, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride as the crosslinker, hinokitiol as the antibacterial agent, and dicalcium phosphate anhydrous (DCPA) micron particles for osteoconduction. Results show that the hydrogel membrane with added DCPA and impregnated hinokitiol has a fixation index higher than 88%. When only a small amount of DCPA is added, the tensile strength does not decrease significantly. The tensile strength decreases considerably when a large amount of modified DCPA is added. The stress–strain curve shows that the presence of a large amount of hinokitiol in hydrogel membranes results in considerably improved deformation and toughness properties. Each group impregnated with hinokitiol exhibits obvious antibacterial capabilities. Furthermore, the addition of DCPA and impregnation with hinokitiol does not exert cytotoxicity on cells in vitro, indicating that the designed amount of DCPA and hinokitiol in this study is appropriate. After a 14-day cell culture, the hydrogel membrane still maintains a good shape because the cells adhere and proliferate well, thus delaying degradation. In addition, the hydrogel containing a small amount of DCPA has the best cell mineralization effect. The developed hydrogel has a certain degree of flexibility, degradability, and bifunctionality and is superficial. It can be used in guided tissue regeneration in clinical surgery.

Direct Synthesis of Polyaromatic Cyclophanes Containing Bis-Methylene-Interrupted Z-Double Bonds and Study of Their Antitumor Activity In Vitro

An original synthetic route was developed for the preparation of previously unknown unsaturated polyaromatic macrolactones containing a 1Z,5Z-diene moiety in 48–71% yields and with >98% stereoselectivity. The method is based on intermolecular cyclocondensation of aromatic dicarboxylic acids with α,ω-alka-nZ,(n+4)Z-dienediols (1,12-dodeca-4Z,8Z-dienediol, 1,14-tetradeca-5Z,9Z-dienediol, 1,18-octadeca-7Z,11Z-dienediol) mediated by N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC)/4-dimethylaminopyridine (DMAP). The unsaturated diols were prepared by successive homo-cyclomagnesiation of tetrahydropyran ethers of O-containing 1,2-dienes with EtMgBr in the presence of Mg metal and the Cp2TiCl2 catalyst (10 mol.%) and subsequent treatment with 0.1 equiv. of para-toluenesulfonic acid of pyran ethers formed after the acid hydrolysis of magnesacyclopentanes. The resulting cyclophanes exhibited high cytotoxic activity in vitro against Jurkat, K562, U937, and HL60 cancer lines. Additionally, the synthesized products were studied for their effect on mitochondria, ability to induce apoptosis, and influence on the cell cycle using modern flow cytometry methods.

Preparation of Soluble POSS-Linking Polyamide and Its Application in Antifogging Films

In this study, we prepared a polyhedral oligomeric silsesquioxane (POSS)-linking polyamide (POSS polyamide) by a polycondensation of ammonium-functionalized POSS (POSS-A) and carboxyl-functionalized POSS (POSS-C) in dehydrated dimethyl sulfoxide (DMSO) using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) as condensing agents. The obtained POSS polyamide was soluble in various highly polar solvents, and it could form a self-standing film. FT-IR, 1H NMR, and 29Si NMR analyses showed that POSS polyamide is a polymer in which POSS-A and POSS-C are linked almost linearly by amide bonds. Furthermore, the cast film obtained by heat-treating the polymer at 150 °C for 30 min exhibited excellent transparency and hard-coating (pencil scratch test: 5H) and antifogging properties (evaluation by water vapor exposure).

Biomaterials with Potential Use in Bone Tissue Regeneration—Collagen/Chitosan/Silk Fibroin Scaffolds Cross-Linked by EDC/NHS

Blending of different biopolymers, e.g., collagen, chitosan, silk fibroin and cross-linking modifications of these mixtures can lead to new materials with improved physico-chemical properties, compared to single-component scaffolds. Three-dimensional scaffolds based on three-component mixtures of silk fibroin, collagen and chitosan, chemically cross-linked, were prepared and their physico-chemical and biological properties were evaluated. A mixture of EDC (N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride) and NHS (N-hydroxysuccinimide) was used as a cross-linking agent. FTIR was used to observe the position of the peaks characteristic for collagen, chitosan and silk fibroin. The following properties depending on the scaffold structure were studied: swelling behavior, liquid uptake, moisture content, porosity, density, and mechanical parameters. Scanning Electron Microscopy imaging was performed. Additionally, the biological properties of these materials were assessed, by metabolic activity assay. The results showed that the three-component mixtures, cross-linked by EDC/NHS and prepared by lyophilization method, presented porous structures. They were characterized by a high swelling degree. The composition of scaffolds has an influence on mechanical properties. All of the studied materials were cytocompatible with MG-63 osteoblast-like cells.

An Impedance Based Electrochemical Immunosensor for Aflatoxin B1 Monitoring in Pistachio Matrices

Aflatoxins are highly toxic fungal secondary metabolites that often contaminate food and feed commodities. An electrochemical immunosensor for the determination of aflatoxin B1 (AFB1) was fabricated by immobilizing monoclonal AFB1 antibodies onto a screen-printed gold electrode that was modified with carbo-methyldextran by N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide cross-linking. An electrochemical interfacial modelling of biomolecular recognition was suggested and reasonably interpreted. Impedance technology was employed for the quantitative determination of AFB1. The limit of detection concentration of AFB1 for standard solutions and spiked pistachio samples was 0.5 ng/mL and 1 ng/mL, respectively. The immunosensor was able to successfully determine AFB1 concentrations in the range of 4.56–50.86 ng/mL in unknown pistachio samples. Comparative chromatographic analysis revealed that AFB1 concentrations that were higher than 345 ng/mL were not within the immunosensor’s upper limits of detection. Selectivity studies against Ochratoxin A and Aflatoxin M1 demonstrated that the proposed AFB1 immunosensor was able to differentiate between these other fungal mycotoxins. The novel electrochemical immunosensor approach has the potential for rapid sample screening in a portable, disposable format, thus contributing to the requirement for effective prevention and the control of aflatoxin B1 in pistachios.

In Vitro Characterization of Multilamellar Fibers with Uniaxially Oriented Electrospun Type I Collagen Scaffolds

Fabrication of an appropriate scaffold is critical in order to recapitulate the architecture and functionality of the native tissue. In this study, we attempted to create favorable collagen fiber alignment and multilamellar with uniaxially oriented layers, using a disc collector by turning mats 90 degrees horizontally at specific times. Different concentrations of rat tail-derived type I collagen (3, 6, 8% w/v) in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) are used for electrospinning affairs. The 6% w/v collagen at an applied voltage of 20 kV and collector rotation of 2500 rpm was selected to exhibit bead-free homogeneous nanofiber with fiber thickness of 0.14 ± 0.4 µm, maximum thickness of 0.5 ± 0.08 µm, and 60% porosity. Also, scanning electron microscope images of electrospun fibers showed 3D multilamellar scaffold with the goodness of 96.5% ± 0.8 in each aligned uniaxially oriented fiber layer. Cross-linking of collagen fibers with N-(3-dimethylaminopropyl)-N0-ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) reduced the fiber degradation rate and preserved the fiber morphology and alignment. The multilamellar mat showed significant increase in tensile strength and average breaking elongation in comparison with unilamellar mat. In vitro cell culture, using human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) on cross-linked scaffold, showed improvement in cell proliferation, attachment, migration, and intercellular junction with a flattened morphology. Raman spectra revealed the preservation of collagen structure. In addition, Raman spectra of the cell containing scaffold were the same as those of an intact intervertebral disc as a sample to be used in engineering tissues. In conclusion, our results showed that the 3D multilamellar collagen nanofibrous scaffold is more appropriate for the tissues that have multilamellar structure.

Chemically Fueled Transient Geometry Changes in Diphenic Acids

Transient changes in molecular geometry are key to the function of many important biochemical systems. Here, we show that diphenic acids undergo out-of-equilibrium changes in dihedral angle when reacted with a carbodiimide chemical fuel. Treatment of appropriately functionalized diphenic acids with EDC (<i>N</i>-(3-dimethylaminopropyl)-<i>N</i>′-ethylcarbodiimide hydrochloride) yields the corresponding diphenic anhydrides, reducing the torsional angle about the biaryl bond by approximately 45°, regardless of substitution. In the absence of steric resistance, the reaction is well-described by a simple mechanism; the resulting kinetic parameters can be used to derive important properties of the system, such as yields and lifetimes. The reaction tolerates steric hindrance ortho to the biaryl bond, although the competing formation of (transient) byproducts complicates quantitative analysis.