Enhanced Cell Proliferation and Osteogenesis Differentiation through a Combined Treatment of Poly-L-Lysine-Coated PLGA/Graphene Oxide Hybrid Fiber Matrices and Electrical Stimulation

Bone tissue engineering scaffold provides an effective treatment for bone defect repair. Biodegradable bone scaffold made of various synthetic and natural materials can be used as bone substitutes and grafts for defect site, which has great potential to support bone regeneration. Regulation of cell-scaffold material interactions is an important factor for modulating the cellular activity in bone tissue engineering scaffold applications. Thus, the hydrophilic, mechanical, and chemical properties of scaffold materials directly affect the results of bone regeneration and functional recovery. In this study, a poly-L-lysine (PLL) surface-modified poly(lactic-co-glycolic acid) (PLGA)/graphene oxide (GO) (PLL-PLGA/GO) hybrid fiber matrix was fabricated for bone tissue regeneration. Characterization of the resultant hybrid fiber matrices was done using scanning electron microscopy (SEM), contact angle, and a material testing machine. According to the results obtained from the test above, the PLL-PLGA/GO hybrid fiber matrices exhibited high wettability and mechanical strength. The special surface characteristics of PLL-PLGA/GO hybrid fiber matrices were more beneficial for protein adsorption and inhibit the proliferation of pathogens. Moreover, the enhanced regulation of MC3T3-E1 cell proliferation and differentiation was observed, when the resultant hybrid fiber matrices were combined with electrical stimulation (ES). The cellular response of MC3T3-E1 cells including cell adhesion, proliferation, alkaline phosphatase (ALP) activity, calcium deposition, and osteogenesis-related gene expression was significantly enhanced with the synergistic effect of resultant hybrid fiber matrices and ES. These data indicate that the PLL-PLGA/GO hybrid fiber matrices supported the cellular response in terms of cell proliferation and osteogenesis differentiation in the presence of electrical stimulation, which could be a potential treatment for bone defect.

Fabrication and Characterization of Electrospun Nanofibers for the Modified Release of the Chronobiotic Hormone Melatonin

Objective: Aiming at the modified release of melatonin (MLT), electrospun-MLT loaded nanofibers, filled into hard gelatin and DRcapsTM capsules, were used as formulants. Methods: Cellulose acetate, polyvinylpyrrolidinone and hydroxypropylmethylcellusose (HPMC 2910) were used for the preparation of the fiber matrices through electrospinning. The in vitro modified release profile of MLT from the fabricated matrices in gastrointestinal-like fluids was studied. At pH 1.2, the formulations CA1, CA2, PV1, HP1, HP2 and the composite formulations CAPV1-CAPV5 in hard gelatin capsules exhibited fast MLT release. Results: In general, the same trend was observed at pH 6.8, with the exception of CAPV1 and CAPV2. These two composite formulations delivered 52.08% and 75.25% MLT, respectively at a slower pace (6 h) when encapsulated in DRcapsTM capsules. In all other cases, the release of MLT from DRcapsTM capsules filled with the MLT-loaded nanofibers reached 100% at 6h. Conclusion: These findings suggest that the MLT-loaded nanofibrous mats developed in this study exhibit a promising profile for treating sleep dysfunctions.

Influence of additives on physico-chemical properties of electrospun poly(L-lactide)

Electrospun poly(L-lactide) (PLLA) nonwoven represent potential options for biodegradable medical implants. They can be manufactured with high reproducibility and do offer the potential for chemical modification to alter matrix properties. In our study, we investigate the mechanical, thermal and morphological properties of PLLA fiber matrices. Fibrous nonwovens were fabricated from polymer solution by needle electrospinning. The polymer solutions were loaded with Triton X-100 (TX- 100), formic acid and tetraethyl ammonium chloride (TEAC) with respect to polymer weight. Morphology of the PLLA nonwoven scaffolds was examined with SEM. We performed uniaxial tensile tests and differential scanning calorimetry (DSC). Different concentrations of the additives TEAC, formic acid and Triton X-100 lead to strong changes regarding mechanical and thermal properties of the electrospun PLLA fiber matrices. In comparison with mechanical properties of established biological tissue materials, the results indicate the suitability for medical applications.

Multi-component diffusion mass transfer in nonselective IEX matrices with the noval displacement effect (NDE) for the concentration waves of the components – diffusants

There is presented the computerized modeling for the Diffusion Multicomponents (i=1A; 2B;3C)Mass Transfer (MMT) kinetics in the classical nonselective IEx Matrices. The Noval Displacement Effect(NDE) for the Xi(distance,Time)-concentration waves propagating in the IEx matrix is determined. TheW(ave)+-concept is presented here for the Xi-concentration waves of the i-components-diffusants whichpropagate (with multicomponent {DA,DB,DC}-diffusivities) inside the nonselective IEx matrices. The NDEeffect described is possible only for the definite conditions pointed in the last part of the publication (S.5,6).In the result of the computerized simulation of the ternary (R_1A)resin/(2B + 3C)solution IEx DiffusionMMT there is demonstrated visually and obviously the Noval Displacement Effect (NDE) inside the r-bead&ro-fiber matrices of the nonselective IEx resin for the distance-time behavior of the two invading XC,XBconcentrationwaves of the i=2B,3C-components. The initial loading of the r-bead; ro-fiber of the IEx matrixis composed by the first (1A+)-component-diffusant. There is demonstrated the non-monotonic behavior ofthe kinetic FB(T)-curve with the availability of the kinetic maximum- FBmax as the consequence of the NDEffectfor the interactive X3C,X2B-concentration waves which diffuse in the IEx r(ro)-matrices.The original author’s visualization method is used for the NDE description with the two «coupled»Figures, namely the pair of Figs. : [left -{Xi}|{Fi}-right] arranged «in line&abreast». The «coupled» picturesexamples are presented visually in S.3. In this cases the {Xi}-concentration waves (left) are arranged «inline&abreast» with the {Fi}-kinetic curves (right). Such new author’s method of the «coupled Figures»namely: «left -{Xi} | {Fi}-right « plays the crucial role in the demonstration of the NDEffect for the diffusionIEx MMT in the non-selective ion exchangers.

Three-dimensional multiscale fiber matrices: development and characterization for increased HepG2 functional maintenance for bio-artificial liver application

One-step development of three-dimensional multiscale fiber matrices to enhance attachment, proliferation, and characteristic functions of HepG2 cells.