Molecularly Imprinted Membrane Produced by Electrospinning for β-Caryophyllene Extraction

Molecularly imprinted membrane of β-caryophyllene (MIM-βCP) was fabricated incorporating β-caryophyllene molecularly imprinted polymer nanoparticles (βCP-NP) into polycaprolactone (PCL) fibers via electrospinning. The βCP-NP were synthesized by precipitation polymerization using the βCP as a template molecule and acrylic acid as a functional monomer in the proportion of 1:4 mol, respectively. Atomic force microscopy images and X-ray diffraction confirmed the nanoparticles' incorporation into MIM-βCP. MIM-βCP functionalization was evaluated by gas chromatography. The binding capacity was 1.80 ± 0.05 μmol/cm², and the selectivity test was performed with a mixing solution of βCP and caryophyllene oxide, as an analog compound, that extracted 77% of the βCP in 5 min. The electrospun MIM-βCP can be used to detect and extract the βCP, applications in the molecular sieve, and biosensor production and may also contribute as an initial methodology to enhance versatile applications in the future, such as in the treatment of skin diseases, filters for extraction, and detection of βCP to prevent counterfeiting of commercial products, and smart clothing with insect-repellent properties.

Functionalized cell-free scaffolds for bone defect repair inspired by self-healing of bone fractures: A review and new perspectives

Studies have demonstrated that scaffolds, a component of bone tissue engineering, play an indispensable role in bone repair. However, these scaffolds involving ex-vivo cultivated cells seeded have disadvantages in clinical practice, such as limited autologous cells, time-consuming cell expansion procedures, low survival rate and immune-rejection issues. To overcome these disadvantages, recent focus has been placed on the design of functionalized cell-free scaffolds, instead of cell-seeded scaffolds, that can reduplicate the natural self-healing events of bone fractures, such as inflammation, cell recruitment, vascularization, and osteogenic differentiation. New approaches and applications in tissue engineering and regenerative medicine continue to drive the development of functionalized cell-free scaffolds for bone repair. In this review, the self-healing processes were highlighted, and approaches for the functionalization were summarized. Also, ongoing efforts and breakthroughs in the field of functionalization for bone defect repair were discussed. Finally, a brief summery and new perspectives for functionalization strategies were presented to provide guidelines for further efforts in the design of bioinspired cell-free scaffolds.

Microfluidic Fabrication of Bioinspired Cavity-Microfibers for 3D Scaffolds

We present a gas-in-water microfluidic method to precisely fabricate well-controlled versatile microfibers with cavity knots (named cavity-microfiber), like tiny-cavity-microfiber, hybrid-cavity-microfiber, cavity-microfiber, and chained microfiber. The cavity-microfibers are endowed with tunable morphologies, unique surface properties, high specific surface area, assembling ability, flexibility, cytocompatibility, and hydroscopicity. We assemble cavity-microfibers as 3D scaffolds for culturing the human umbilical vein endothelial cells (HUVECs) and dehumidifying. The HUVECs on the scaffolds demonstrate good cell viability and 3D HUVECs frameworks, confirming the unique cytocompatibility of cavity-microfiber. And the cavity-microfibers and their scaffolds also demonstrate excellent dehumidifying ability and large-scale dehumidifying, respectively. Our cavity-microfiber can offer a broad range of applications in sensor, wearable electronics, dehumidifying, water collection engineering, drug delivery, biomaterials, and tissue engineering.

Promoting Endothelial Cell Affinity and Antithrombogenicity of Polytetrafluoroethylene (PTFE) by Mussel-Inspired Modification and RGD/Heparin Grafting

When used as small-diameter vascular grafts (SDVGs), synthetic biomedical materials like polytetrafluoroethylene (PTFE) may induce thrombosis and intimal hyperplasia due to the lack of an endothelial cell layer. Modification of the PTFE in an aqueous solution is difficult because of its hydrophobicity. Herein, aiming to simultaneously promote endothelial cell affinity and antithrombogenicity, a mussel-inspired modification approach was employed to enable the grafting of various bioactive molecules like RGD and heparin. This approach involves a series of pragmatic steps including oxygen plasma treatment, dopamine (DA) coating, polyethylenimine (PEI) grafting, and RGD or RGD/heparin immobilization. Successful modification in each step was verified via Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Plasma treatment increased the hydrophilicity of PTFE, thereby allowing it to be efficiently coated with dopamine. Grafting of dopamine, RGD, and heparin led to an increase in surface roughness and a decrease in water contact angle due to increased surface energy. Platelet adhesion increased after dopamine and RGD modification, but it dramatically decreased when heparin was introduced. All of these modifications, especially the incorporation of RGD, showed favorable effects on endothelial cell attachment, viability, and proliferation. Due to strong cell-substrate interactions between endothelial cells and RGD, the RGD/heparin-grafted PTFE demonstrated high endothelial cell affinity. This facile modification method is highly suitable for all hydrophobic surfaces and provides a promising technique for SDVG modification to stimulate fast endothelialization and effective antithrombosis.

Collagen-coated nano-electrospun PCL seeded with human endometrial stem cells for skin tissue engineering applications

Human endometrial stem cells (hEnSCs) are known as an attractive source of stem cells for regenerative medicine. hEnSCs are easily isolated and are capable of repairing uterine through their strong ability of creating new capillaries. In this study, a three-dimensional (3D) nanofibrous polycaprolactone (PCL)/collagen scaffold was fabricated and characterized in order to be applied as a new approach for skin reconstruction. Furthermore, the behavior of hEnSCs on this scaffold was investigated. First, a PCL 3D scaffold was constructed using electrospinning technique. Plasma treated and PCL was grafted by collagen. The constructs were characterized for mechanical and structural properties. Cell attachment, proliferation, viability, and differentiation of hEnSCs were assessed after being seeded on PCL and PCL/collagen scaffolds using scanning electron microscopy, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and real-time polymerase chain reaction tests. The results showed higher wettability for the PCL/collagen scaffold with desirable mechanical and structural characteristics compared to PCL and collagen alone. The attachment and proliferation rates of hEnSCs on the PCL/collagen scaffold were higher compared to those on the bare PCL. Hence, hEnSCs are newly discovered stem cell source for skin tissue engineering in vitro, particularly when developed on PCL/collagen nanofiber scaffolds. Therefore, application of hEnSCs for skin regeneration is a novel therapeutic approach for temporary skin substitute. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1578-1586, 2018.

The effect of fiber size and pore size on cell proliferation and infiltration in PLLA scaffolds on bone tissue engineering

The scaffold microstructure has a great impact on cell functions in tissue engineering. Herein, the PLLA scaffolds with hierarchical fiber size and pore size were successfully fabricated by thermal-induced phase separation or combined thermal-induced phase separation and salt leaching methods. The PLLA scaffolds were fabricated as microfibrous scaffolds, microfibrous scaffolds with macropores (50–350 µm), nanofibrous scaffolds with micropores (100 nm to 10 µm), and nanofibrous scaffolds with both macropores and micropores by tailoring selective solvents for forming different fiber size and pre-sieved salts for creating controlled pore size. Among the four kinds of PLLA scaffolds, the nanofibrous scaffolds with both macropores and micropores provided a favorable microenvironment for protein adsorption, cell proliferation, and cell infiltration. The results further confirmed the significance of fiber size and pore size on the biological properties, and a scaffold with both micropores and macropores, and a nanofibrous matrix might have promising applications in bone tissue engineering.

Nanostructured surface of electrospun PCL/dECM fibres treated with oxygen plasma for tissue engineering

Nanoscale patterns on the surface of PCL-based dECM were developed by a selective plasma treatment.