Biological response, antibacterial properties of ZrO2/hydroxyapatite/graphene oxide encapsulated into nanofibrous scaffolds of polylactic acid for wound healing applications.

Designing proper nanofibrous scaffolds for wound healing applications is a necessity for improving the health care system. Hydroxyapatite (HAP), zirconia (ZrO2), and graphene oxide (GO) nanosheets have been encapsulated in mono, di, or tri phases into nanofibrous scaffolds of polylactic acid (PLA). The structure of nanofibrous scaffolds is confirmed using XRD, XPS, while FESEM inspected the surface morphology. The surface morphology detection exhibited that the scaffolds have been formed in networked nanofibers with diameters from 1.19 to 2.38 to 0.59-1.42 µm, while the maximum height of the roughness increased from 610.4 to 809 nm for HAP@PLA and HAP/ZrO2/GO@PLA, respectively. The contact angle was measured and showed a decreasing trend from 101.2 ± 4.1° and 89.1 ± 5.4° for HAP@PLA and HAP/ZrO2/GO@PLA nanofibrous scaffolds. Moreover, the mechanical properties were examined and revealed that ZrO2 dopant induced a significant enhancement into the tensile strength, which increased from 3.49 ± 0.3 to 8.45 ± 1.1 MPa for the nanofibrous scaffolds of HAP@PLA and HAP/ZrO2/GO@PLA, respectively. The incorporation of ternary phases into PLA nanofibers promoted the cell viability to be around 98.2 ± 5%. The antibacterial potency has been investigated and showed that the activity increased to 69.2 ± 3.6 and 78.1 ± 4.5% against E. coli and S. aureus, respectively. Additionally, human fibroblasts proliferated on the surface and pores of nanofibrous scaffolds and significantly grown upon the compositional variation.

Nanofibrous scaffolds ofϵ-polycaprolactone containing Sr/Se-hydroxyapatite/graphene oxide for tissue engineering applications.

For wound healing applications, a scaffold of biocompatible/porous networks is crucial to support cell proliferation and spreading. Therefore,ϵ-polycaprolactone (PCL) nanofibrous scaffolds containing co-dopants of strontium/selenium in hydroxyapatite (HAP) were modified with different contributions of graphene oxide (GO) via the laser ablation technique. The obtained compositions were investigated using XRD, TEM and FESEM. It was evident that fiber diameters were in the range of 0.15-0.30µm and 0.35-0.83µm at the lowest and highest concentration of GO respectively, while the maximum height of the roughness progressed to 393 nm. The toughness behavior was promoted from 5.77 ± 0.21 to 9.16 ± 0.29 MJ m-3upon GO from the lowest to the highest contribution, while the maximum strain at break reached 148.1% ± 0.49% at the highest concentration of GO. The cell viability indicated that the fibrous scaffold was biocompatible. The investigation of the HFB4 cell attachments towards the fibrous compositions showed that with the increase of GO, cells tended to grow intensively through the scaffolds. Furthermore, the proliferation of cells was observed to be rooted in the porous structure and spreading on the surface of the scaffold. This progression of cells with an increase in GO content may provide a simple strategy not only to enhance the mechanical properties, but also to manipulate a nanofibrous scaffold with proper behaviors for biomedical applications.

Gold as a dopant in selenium-containing carbonated hydroxyapatite fillers of nanofibrous ε-polycaprolactone scaffolds for tissue engineering.

The necessity for finding a compromise between mechanical and biological properties of biomaterials spurs the investigation of the new methods to control and optimize scaffold processing for tissue engineering applications. A scaffold composed of ε-polycaprolactone fibers reinforced with carbonated hydroxyapatite (CHAP) dually doped with selenite oxyanions (Se) and cationic gold (Au) was synthesized using the electrospinning technique and studied at different contents of Au. Despite the fact that the amount of the Au dopant was relatively low, variations to it induced significant microstructural changes, affecting the cell response and mechanical properties in return. Au nanoparticles segregated as a separate, ternary phase at the highest Au content, corresponding to x = 0.8 in the AuxCa10-1.5x(PO4)5.8(SeO2)0.2-x(CO3)x(OH)2 stoichiometric formula of Au/Se-CHAP. Their appearance coincided with a rapid degeneration in the density and adhesion of osteoblastic cells grown on the scaffolds. In spite of this adverse effect, the cell spreading and proliferation improved with increasing the amount of the Au dopant in the Au/Se-CHAP particles of the scaffold in the x = 0.0-0.6 range, suggesting that the biological effects of Au in the ionic and in the nanoparticulate form on the implant integration process may be diametrically opposite. The addition of Au had a dramatic effect on some mechanical properties, such as toughness and strain at break, which were both reduced twice upon the introduction of Au into Se-CHAP at the lowest amount (x = 0.2) compared to the Au-free composite. The significant variation of physical and biological properties of these composite scaffolds with trace changes in the content of the Au dopant inside the ceramic filler particles is promising, as it provides a new, relatively subtle avenue for tailoring the properties of tissue engineering scaffolds for their intended biomedical applications.

Multifunctional magnetic-gold nanoparticles for efficient combined targeted drug delivery and interstitial photothermal therapy.

Abundant efforts have recently been made to design potent theranostic nanoparticles, which combine diagnostic and therapeutic agents, for the effective treatment of cancer. In this study, we developed multifunctional magnetic gold nanoparticles (MGNPs) that are able to (i) selectively deliver the drug to the tumor site in a controlled-release manner, either passively or by using magnetic targeting; (ii) induce photothermal therapy by producing heat by near-infrared (NIR) laser absorption; and (iii) serve as contrast agents for magnetic resonance imaging (MRI) (imaging-guided therapy). The prepared MGNPs were characterized by different physical techniques. They were then coated and conjugated with polyethylene glycol (PEG) and doxorubicin (DOX) to form MGNP-DOX conjugates. The high efficacy of MGNP-DOX for combined chemo-photothermal therapy was observed both in vitro and in vivo. The effectiveness of MGNP-DOX as theranostic nanoparticles was confirmed by histopathological examination and immunohistochemical studies. Moreover, MGNP-DOX showed good potential as MRI contrast agents for guided chemo-photothermal synergistic therapy.