High-Resolution Performance of Polycaprolactone Functionalized with Guanidinium Ionic Liquid for Gas Chromatography

This work firstly reported a new polycaprolactone based material functionalized with guanidinium ionic liquid (PCL-GIL) as the stationary phase with high resolution performance for capillary gas chromatography (GC). It is composed of polycaprolactone (PCL) and guanidinium ionic liquid (GIL) with amphiphilic conformation. The PCL-GIL capillary column coated by static method exhibited high column efficiency of 3942 plates/m and moderate polarity. As a result, the PCL-GIL column exhibited high-resolution capability. For a mixture of 27 analytes with a wide ranging polarity and outperformed the PCL-2OH and HP-35 columns, showing its advantageous separation capability for analytes of diverse types. Moreover, the PCL-GIL column showed high resolving capability for various positional isomers and cis-/trans-isomers, including alkylbenzenes, chlorobenzenes, naphthalenes, bromonitrobenzenes, chloronitrobenzenes, benzaldehydes, phenols, alcohols, respectively. In a word, PCL derivatized by GIL units as a new type of stationary phase has a promising future in GC separations.     

Production of polycaprolactone nanoparticles with hydrodynamic diameters below 100 nm

Cancer is a worldwide increasing burden and its therapy is often challenging and causes severe side effects in healthy tissue. If drugs are loaded into nanoparticles, side effects can be reduced, and efficiency can be increased via the enhanced permeability and retention effect. This effect is based on the fact that nanoparticles with sizes from 10 to 200 nm can accumulate in tumor tissue due to their leaky vasculature. In this work, we produced polycaprolactone (PCL) in the sizes 1.8, 5.4, and 13.6 kDa and were able to produce spherical shaped nanoparticles with mean diameters of 64 ± 19 nm out of the PCL_5.4 and 45 ± 8 nm out of the PCL_13.6 reproducibly. By encapsulation of paclitaxel the diameter of that nanoparticles did not increase, and we were able to encapsulate 73 ± 7 fmol paclitaxel per 1000 particles in the PCL_5.4‐nanoparticles and 35 ± 8 fmol PTX per 1000 PCL_13.6‐nanoparticles. Furthermore, we coupled the aptamer S15 to preformed PCL_5.4‐nanoparticles resulting in particles with a hydrodynamic diameter of 153 nm. This offers the opportunity to use these nanoparticles for targeted drug delivery.     

Biomimetic micropatterned multi-channel nerve guides by templated electrospinning

This report describes a new approach for fabricating microchannels within three-dimensional electrospun constructs. These key features serve to mimic the fascicular architecture and fibrous extracellular matrix found in native nerve. Both electrospun fibers and multi-channeled structure nerve guides have become areas of increasing interest for their beneficial roles in nerve repair. However, to the best of our knowledge, this is the first report of a guide that incorporates both. Multiple parallel channels provide a greater number of defined paths and increased surface area compared to cylindrical guides. Additionally, the fibrous nature of electrospun fibers permits better mass transport than solid-walled constructs. The flexible fabrication scheme allows tailoring of nerve guide parameters such as channel diameters ranging from 33 to 176 μm and various wall thicknesses. Channel and fiber structures were assessed by optical and electron microscope images. Geometric calculations estimated a porosity of over 85% for these guides with 16% or less from the channels. In vitro culture with Schwann cells demonstrated cellular infiltration into channels with restricted migration between fibers. Finally, cell proliferation and survival throughout the guide indicates that this design warrants future in vivo examination.     

Micropatterning and characterization of electrospun poly(ε‐caprolactone)/gelatin nanofiber tissue scaffolds by femtosecond laser ablation for tissue engineering applications

Experimental investigations aimed at assessing the effectiveness of femtosecond (FS) laser ablation for creating microscale features on electrospun poly(ε‐caprolactone) (PCL)/gelatin nanofiber tissue scaffold capable of controlling cell distribution are described. Statistical comparisons of the fiber diameter and surface porosity on laser‐machined and as‐spun surface were made and results showed that laser ablation did not change the fiber surface morphology. The minimum feature size that could be created on electrospun nanofiber surfaces by direct‐write ablation was measured over a range of laser pulse energies. The minimum feature size that could be created was limited only by the pore size of the scaffold surface. The chemical states of PCL/gelatin nanofiber surfaces were measured before and after FS laser machining by attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy and X‐ray photoelectron spectroscopy (XPS) and showed that laser machining produced no changes in the chemistry of the surface. In vitro, mouse embryonic stem cells (mES cells) were cultured on as‐spun surfaces and in laser‐machined microwells. Cell densities were found to be statistically indistinguishable after 1 and 2 days of growth. Additionally, confocal microscope imaging confirmed that spreading of mES cells cultured within laser‐machined microwells was constrained by the cavity walls, the expected and desired function of these cavities. The geometric constraint caused statistically significant smaller density of cells in microwells after 3 days of growth. It was concluded that FS laser ablation is an effective process for microscale structuring of these electrospun nanofiber tissue scaffold surfaces. Biotechnol. Bioeng. 2011; 108:116–126. © 2010 Wiley Periodicals, Inc.     

Pseudozyma jejuensis sp. nov., a novel cutinolytic ustilaginomycetous yeast species that is able to degrade plastic waste

An ustilaginomycetous anamorphic yeast, isolated from orange leaves on Jeju island in South Korea, represents a novel Pseudozyma species according to morphologic and physiologic findings and molecular taxonomic analysis using the D1/D2 domains of the large subunit (26S) rRNA gene and the internally transcribed spacer (ITS) 1+2 regions. The name Pseudozyma jejuensis sp. nov. is proposed for this novel species, with OL71(T) (=KCTC 17482(T)=CBS 10454(T)) as type strain. In the present study, we have also demonstrated that Pseudozyma jejuensis OL71 is capable of producing cutinase and degrading polycaprolactone. These results suggest that Pseudozyma jejuensis or its cutinase may be useful for the biological degradation of plastic waste.     

Fabrication of highly porous scaffolds for tissue engineering based on star-shaped functional poly(ε-caprolactone)

The potential of novel functional star‐shaped poly(ε‐caprolactone)s of controlled molecular weight and low molecular weight distribution bearing acrylate end groups as material for biomedical applications was demonstrated in this study. The polymers were functionalized via Michael‐type addition of amino acid esters containing amino or thiol groups showing the potential for immobilization of biomolecules. Furthermore, scaffolds of different geometries were prepared by uniaxial freezing of polymer solutions followed by freeze drying. Different solvents and polymer concentrations were investigated, resulting in scaffolds with porosities between 76 and 96%. Mechanical properties of the scaffolds were investigated and the morphology was determined via scanning electron microscopy. Scaffolds with interconnected channels were prepared using benzene, 1,2‐dichloroethane or dioxane as solvent. The tubular longitudinal pores in honeycomb arrangement extend throughout the full extent of the scaffolds (typical pore sizes: 20–100 µm). Biotechnol. Bioeng. 2011; 108:694–703. © 2010 Wiley Periodicals, Inc.     

Bone morphogenetic protein-7 incorporated polycaprolactone scaffold has a great potential to improve survival and proliferation rate of the human embryonic kidney cells

Renal failures treatment has been faced with several problems during the last decades. Kidney tissue engineering has been created many hopes to improve treatment procedures with scaffold fabrication that can modulate kidney cells/stem cells migration to the lesion site and increase the survival of these cells at that site with imitating the role of the kidney extracellular matrix. In this study, bone morphogenetic protein-7 (BMP7) as a vital factor for kidney development and regeneration was incorporated in the polycaprolactone (PCL) nanofibers and after morphological, mechanical, and biocompatible characterization, proliferation, and survival of the human embryonic kidney cells (HEK) were investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), flow cytometry, and gene expression while cultured on scaffolds. Mechanical properties of the PCL nanofibers modulated after combining with BMP7 and hydration degree, protein adsorption and cell adhesion were enhanced in PCL-BMP7 compared to the pure PCL. Proliferation rate and growth increased significantly in HEK cells cultured on PCL-BMP7 when compared with that of PCL and tissue culture plate, whereas these data were also confirmed via significant decrease in apoptotic genes expression level in HEK cell cultured on PCL-BMP7. According to the results, PCL-BMP7 demonstrated positive effects on the survival and proliferation rate of the kidney cells and showed has also a great potential to use as a bioimplant for kidney tissue engineering applications.     

Composite thin film and electrospun biomaterials for urologic tissue reconstruction

A replacement material for autologous grafts for urinary tract reconstruction would dramatically reduce the complications of surgery for these procedures. However, acellular materials have not proven to work sufficiently well, and cell‐seeded materials are technically challenging and time consuming to generate. An important function of the urinary tract is to prevent urine leakage into the surrounding tissue—a function usually performed by the urothelium. We hypothesize that by providing an impermeable barrier in the acellular graft material, urine leakage would be minimized, as the urothelium forms in vivo. However, since urothelial cells require access to nutrients from the supporting vasculature, the impermeable barrier must degrade over time. Here we present the development of a novel biomaterial composed of the common degradable polymers, poly(ε‐caprolactone) and poly(L ‐lactic acid) and generated by electrospinning directly onto spin‐coated thin films. The composite scaffolds with thin films on the luminal surface were compared to their electrospun counterparts and commercially available small intestinal submucosa by surface analysis using scanning electron microscopy and by analysis of permeability to small molecules. In addition, the materials were examined for their ability to support urothelial cell adhesion, proliferation, and multilayered urothelium formation. We provide evidence that these unique composite scaffolds provide significant benefit over commonly used acellular materials in vitro and suggest that they be further examined in vivo. Biotechnol. Bioeng. 2011; 108:207–215. © 2010 Wiley Periodicals, Inc.     

Incorporated-bFGF polycaprolactone/polyvinylidene fluoride nanocomposite scaffold promotes human induced pluripotent stem cells osteogenic differentiation

Bioactive scaffolds that can increase transplanted cell survival time at the defect site have a great promising potential to use clinically since tissue regeneration or secretions crucially depend on the transplanted cell survival. In this study embedded basic fibroblast growth factor (bFGF)-polycaprolactone-polyvinylidene fluoride (PCL-PVDF) hybrid was designed and fabricated by electrospinning as a bio-functional nanofibrous scaffold for bone tissue engineering. After morphological characterization of the PCL-PVDF (bFGF) scaffold, nanofibers biocompatibility was investigated by culturing of the human induced pluripotent stem cells (iPSCs). Then, the bone differentiation capacity of the iPSCs was evaluated when grown on the PCL-PVDF and PCL-PVDF (bFGF) scaffolds in comparison with culture plate as a control using evaluating of the common osteogenic markers. The viability assay displayed a significant increase in iPSCs survival rate when grown on the bFGF content scaffold. The highest alkaline phosphatase activity and mineralization were detected in the iPSCs while grown on the PCL-PVDF (bFGF) scaffolds. Obtained results from gene and protein expression were also demonstrated the higher osteoinductive property of the bFGF content scaffold compared with the scaffold without it. According to the results, the release of bFGF from PCL-PVDF nanofibers increased survival and proliferation rate of the iPSCs, which followed by an increase in its osteogenic differentiation potential. Taking together, PCL-PVDF (bFGF) nanofibrous scaffold demonstrated that can be noted as a promising candidate for treating the bone lesions by tissue engineering products.