Electrospun hydroxyapatite

In order to improve the properties and the spinnability, fibroin sometimes has been electrospun together with other natural or synthetic polymers (Jin et al., 2002 Park et al., 2004, 2006 Wang et al., 2004, 2006). For instance, Jin et al. (2002) developed an aqueous process for silk electrospinning in combination with PEO. More recently, Cao (2008) used PVA/Silk Fibroin (SF), Gelatin/SF, and Hydroxyapatite (HAP)/SF to produce double-layered (core-shell) nanofibers (mats) by coelectrospinning. 

Chen F et al (2010) Hydroxyapatite nanorods/poly(vinyl pyrolidone) composite nanofibers, arrays and three-dimensional fabrics electrospun preparation and transformation to hydroxyapatite nanostructures. Acta Biomater 6(8) 3013-3020... 

Y. Zhang, J.R. Venugopal, A. El-Turki, S. Ramakrishna, B. Su, C.T. Lim, Electrospun biomimetic nanocomposite nanofibers of hydroxyapatite/chitosan for bone tissue engineering. Biomaterials... 

D. Yang, Y. Jin, Y. Zhou, G. Ma, X. Chen, F. Lu, et al.. In situ mineralization of hydroxyapatite on electrospun chitosan-based nanofi-brous scaffolds, Macromol. Biosd. 8 (2008) 239-246. 

Tyagi, P., Catledge, S.A., Stanishevsky, A., Thomas, V., Vohra, Y.K. Nanomechanical properties of electrospun composite scaffolds based on polycaprolactone and hydroxyapatite. J. Nanosci. Nanotechnol. 9,4839-4845 (2009)... 

Zhang HL, Chen ZQ. Fabrication and characterization of electrospun PLGA/MWNTs/ hydroxyapatite biocomposite scaffolds for bone tissue engineering. J Bioact Compat Pol 2010 25 241-59. 

Various electrospun nanofibers made of PCL, PCL/hydroxyapatite, polystyrene, and SF were surface-modified by air or argon plasma, resulting in an improved cell adhesion and proliferation (Venugopal et al. 2008 Prabhakaran et al. 2008 Yang et al. 2008). PCL nanofibrous scaffolds were surface-modified by a simple plasma treatment process to enhance the Schwann cell adhesion, proliferation, and interactions with the nanofibers necessary for nerve tissue formation (Prabhakaran et al. 2008). The results showed that plasma-treated PCL nanofibrous scaffolds are a cost-effective material compared with PCL/collagen scaffolds and can potentially serve as an ideal tissue-engineered scaffold, especially for peripheral nerve regeneration. 

Chen, J., Chu, B. and Hsiao, B.S. 2006a. Mineralization of hydroxyapatite in electrospun nanofibrous poly(L-lactic acid) scaffolds. 

PMMA/hydroxyapatite bone cement. Both nanostructures were found to capture the radicals produced during the cement polymerization process, thereby hampering their normal course and affecting the mechanical properties of the nanocomposites, especially the one-dimensional nanoform [145]. Recently, we have compared both 1D and 2D carbon nanostructures and the effect of functionalization on the thermomechanical properties. As seen in Figure 10.13, the nanofillers containing carboxylic groups provided the best mechanical response at 1 wt% loading. Additionally, the 2D carbon structures provided better reinforcement in the electrospun fibers when compared to the ID carbon nanomaterials [116,158]. 

Inorganic particles have also been used to produce electrospun scaffolds. Hydroxyapatite (HA) is a calcium phosphate-based ceramic present in natural bone, which has been evaluated for the production of bone scaffolds. Electrospun scaffolds were produced from a blend of PLGA and nanosized HA. When MSC were cultivated on the scaffolds, their osteogenic differentiation was favored. 

Hydroxyapatite (HA) nanoparticles are osteoconductive bioactive ceramics that can support bone cell adhesion and proliferation and accelerate bone defects healing. HA is typically added to polymeric nanofibers to increase their mechanical strength. HA, often in the form of needle-like nanoparticles, was electrospun in the presence of synthetic biocompatible and biodegradable polymers such as PLA [5, 58-60] and PLA-PEG-PLA [61], natural polymers such as chitosan [62] and collagen [63, 64], and blends of natural and synthetic polymers such as PVA/chitosan [65] and PCL/gelatin [66]. 

Mi HY, et al. Thermoplastic polyurethane/hydroxyapatite electrospun scaffolds for bone tissue engineering effects of polymer properties and particle size. J Biomed Mater Res B Appl Biomater 2014 102(7) 1434 14. 

Tetteh G, et al. Electrospun polyurethane/hydroxyapatite bioactive scaffolds for bone tissue engineering the role of solvent and hydroxyapatite particles. J Mech Behav Biomed Mater 2014 39 95-110. 

Mi, H.-Y., Palumbo, S., Jing, X., Tumg, L.-S., Li, W.-J., Peng, X.-F., 2014. Thermoplasticpoly-urethane/hydroxyapatite electrospun scaffolds for bone tissue engineering effects of polymer properties and particle size. Journal of Biomedical Materials Research Part B Applied Biomaterials 1-11. http //dx.doi.Org/10.1002/jbm.b.33122. 

O. H. Kwon (2005). A composite of hydroxyapatite with electrospun biodegradable nanofibers as a tissue engineering material. Journal of Bioscience and Bioengineering 100(1) 43—49. 

Shanmugavel, S., Reddy, V. J., Ramakrishna, S., Lakshmi, B., Dev, V. G. (2014). Precipitation of hydroxyapatite on electrospun polycarpolactone/aloe vera/silk fibroin nanofibrous scaffolds for bone tissue engineering. Journal of Biomaterials Applications, 29(11), 46-58. 

However, electrospinning of a mixture of silk fibroin and inorganic ceramics, such as hydroxyapatite, is still a challenging task. The mechanical properties of electrospun silk fibroin scaffolds can be enhanced by uniformly dispersing hydroxyapatite nanoparticles within silk fibroin nanofibers. Hydroxyapatite nanoparticles were modified by y-glycidox q3ropyltrimethoxysilane for uniform dispersion and enhanced interfacial bonding between hydroxyapatite and silk fibroin fibers. 

Catledge S, lyagi P, Koopman M et al (2004) Electrospun gelatin/hydroxyapatite nanocomposite scaffolds for bone tissue engineering, mater. Res Soc Symp Proc 1094 1094-DD09-05... 

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