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A novel approach to fabricate silk nanofibers containing hydroxyapatite nanoparticles using a three-way stopcock connector.

Sheikh FA, Ju HW, Moon BM, Park HJ, Kim JH, Lee OJ, Park CH - Nanoscale Res Lett (2013)

Bottom Line: In this work, we had successfully used a three-way stopcock connector to mix the two different solutions, and very shortly, this solution is ejected out to form nanofibers due to electric fields.Different blend ratios consisting HAp NPs had been electrospun into nanofibers.These characterization techniques revealed that HAp NPs can be easily introduced in silk nanofibers using a stopcock connector, and this method favorably preserves the intact nature of silk fibroin and HAp NPs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702, South Korea ; Department of Chemistry, University of Texas-Pan American, Edinburg, Texas 78539, USA.

ABSTRACT
Electrospinning technique is commonly used to produce micro- and/or nanofibers, which utilizes electrical forces to produce polymeric fibers with diameters ranging from several micrometers down to few nanometers. Desirably, electrospun materials provide highly porous structure and appropriate pore size for initial cell attachment and proliferation and thereby enable the exchange of nutrients. Composite nanofibers consisting of silk and hydroxyapatite nanoparticles (HAp) (NPs) had been considered as an excellent choice due to their efficient biocompatibility and bone-mimicking properties. To prepare these nanofiber composites, it requires the use of acidic solutions which have serious consequences on the nature of both silk and HAp NPs. It is ideal to create these nanofibers using aqueous solutions in which the physicochemical nature of both materials can be retained. However, to create those nanofibers is often difficult to obtain because of the fact that aqueous solutions of silk and HAp NPs can precipitate before they can be ejected into fibers during the electrospinning process. In this work, we had successfully used a three-way stopcock connector to mix the two different solutions, and very shortly, this solution is ejected out to form nanofibers due to electric fields. Different blend ratios consisting HAp NPs had been electrospun into nanofibers. The physicochemical aspects of fabricated nanofiber had been characterized by different state of techniques like that of FE-SEM, EDS, TEM, TEM-EDS, TGA, FT-IR, and XRD. These characterization techniques revealed that HAp NPs can be easily introduced in silk nanofibers using a stopcock connector, and this method favorably preserves the intact nature of silk fibroin and HAp NPs. Moreover, nanofibers obtained by this strategy were tested for cell toxicity and cell attachment studies using NIH 3 T3 fibroblasts which indicated non-toxic behavior and good attachment of cells upon incubation in the presence of nanofibers.

No MeSH data available.


Related in: MedlinePlus

The XRD results of the obtained nanofibers at 2θ values from 10° to 60°. The inset in the figure shows the 2θ value from 10° to 28°. Pristine nanofibers (spectrum A), silk fibroin nanofibers modified with 10% HAp NPs (spectrum B), 30% HAp NPs (spectrum C), and 50% HAp NPs (spectrum D).
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Figure 11: The XRD results of the obtained nanofibers at 2θ values from 10° to 60°. The inset in the figure shows the 2θ value from 10° to 28°. Pristine nanofibers (spectrum A), silk fibroin nanofibers modified with 10% HAp NPs (spectrum B), 30% HAp NPs (spectrum C), and 50% HAp NPs (spectrum D).

Mentions: XRD can be utilized as a highly stable technique to investigate the crystalline nature of any material. Figure 11 shows the XRD data for the pristine silk nanofibers and its other modified counterparts facilitated using the stopcock connector to support the immediate mixing of aqueous silk/PEO solution and HAp/PEO colloids. In this figure, nanofibers modified with HAp NPs show various diffraction peaks (indicated by arrows) at 2θ values of 31.77°, 32.90°, 34.08°, 40.45°, and 46.71° that correspond to the crystal planes (211), (300), (202), (310), and (222), respectively, which are in proper agreement with the JCPDS database [27,28]. Unfortunately, the silk nanofibers modified with lower concentrations of HAp NPs did not exhibit the strong peak intensities as that of the higher ones showed. The rationale is that the hydroxyl and/or amide groups present in the silk fibroin can capture the calcium and phosphorous groups present in HAp NPs, thereby resulting in the covering of apatite nuclei to X-ray beams to be detected at lower concentrations. However, comparing the higher content counterparts obtained after the addition of HAp NPs, (i.e., silk + 50% HAp NPs) the spectra possess reasonably extra peaks located at the same diffraction angles as that mentioned in the JCPDS database [27,28]. Furthermore, the graph shows the spectra of nanofibers modified with lower concentrations of HAp NPs not showing strong intensity peaks than the higher concentrations. This may be the limitation with XRD technique or may be due to the masking of HAp crystals by silk fibroin. In order to understand the effect caused by the addition of HAp NPs on the nature of silk fibroin nanofibers and to simultaneously put more light on the crystallinity of silk fibroin in nanofibers, the inset in Figure 11 shows the diffraction peaks obtained at 2θ values from 10° to 28°. The broad diffraction peak in this inset shows the scatter peak with 2θ values of 21.9° which is indicating typical amorphous scattering pattern of amorphous silk [29]. Interestingly, it can be observed that this broad peak forms strong peak with increased intensity with nanofibers modified with HAp, which further indicates enrichment in the transformation from randomly arranged to crystalline βchain structure, in the case of nanofibers modified with HAp NPs.


A novel approach to fabricate silk nanofibers containing hydroxyapatite nanoparticles using a three-way stopcock connector.

Sheikh FA, Ju HW, Moon BM, Park HJ, Kim JH, Lee OJ, Park CH - Nanoscale Res Lett (2013)

The XRD results of the obtained nanofibers at 2θ values from 10° to 60°. The inset in the figure shows the 2θ value from 10° to 28°. Pristine nanofibers (spectrum A), silk fibroin nanofibers modified with 10% HAp NPs (spectrum B), 30% HAp NPs (spectrum C), and 50% HAp NPs (spectrum D).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750300&req=5

Figure 11: The XRD results of the obtained nanofibers at 2θ values from 10° to 60°. The inset in the figure shows the 2θ value from 10° to 28°. Pristine nanofibers (spectrum A), silk fibroin nanofibers modified with 10% HAp NPs (spectrum B), 30% HAp NPs (spectrum C), and 50% HAp NPs (spectrum D).
Mentions: XRD can be utilized as a highly stable technique to investigate the crystalline nature of any material. Figure 11 shows the XRD data for the pristine silk nanofibers and its other modified counterparts facilitated using the stopcock connector to support the immediate mixing of aqueous silk/PEO solution and HAp/PEO colloids. In this figure, nanofibers modified with HAp NPs show various diffraction peaks (indicated by arrows) at 2θ values of 31.77°, 32.90°, 34.08°, 40.45°, and 46.71° that correspond to the crystal planes (211), (300), (202), (310), and (222), respectively, which are in proper agreement with the JCPDS database [27,28]. Unfortunately, the silk nanofibers modified with lower concentrations of HAp NPs did not exhibit the strong peak intensities as that of the higher ones showed. The rationale is that the hydroxyl and/or amide groups present in the silk fibroin can capture the calcium and phosphorous groups present in HAp NPs, thereby resulting in the covering of apatite nuclei to X-ray beams to be detected at lower concentrations. However, comparing the higher content counterparts obtained after the addition of HAp NPs, (i.e., silk + 50% HAp NPs) the spectra possess reasonably extra peaks located at the same diffraction angles as that mentioned in the JCPDS database [27,28]. Furthermore, the graph shows the spectra of nanofibers modified with lower concentrations of HAp NPs not showing strong intensity peaks than the higher concentrations. This may be the limitation with XRD technique or may be due to the masking of HAp crystals by silk fibroin. In order to understand the effect caused by the addition of HAp NPs on the nature of silk fibroin nanofibers and to simultaneously put more light on the crystallinity of silk fibroin in nanofibers, the inset in Figure 11 shows the diffraction peaks obtained at 2θ values from 10° to 28°. The broad diffraction peak in this inset shows the scatter peak with 2θ values of 21.9° which is indicating typical amorphous scattering pattern of amorphous silk [29]. Interestingly, it can be observed that this broad peak forms strong peak with increased intensity with nanofibers modified with HAp, which further indicates enrichment in the transformation from randomly arranged to crystalline βchain structure, in the case of nanofibers modified with HAp NPs.

Bottom Line: In this work, we had successfully used a three-way stopcock connector to mix the two different solutions, and very shortly, this solution is ejected out to form nanofibers due to electric fields.Different blend ratios consisting HAp NPs had been electrospun into nanofibers.These characterization techniques revealed that HAp NPs can be easily introduced in silk nanofibers using a stopcock connector, and this method favorably preserves the intact nature of silk fibroin and HAp NPs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702, South Korea ; Department of Chemistry, University of Texas-Pan American, Edinburg, Texas 78539, USA.

ABSTRACT
Electrospinning technique is commonly used to produce micro- and/or nanofibers, which utilizes electrical forces to produce polymeric fibers with diameters ranging from several micrometers down to few nanometers. Desirably, electrospun materials provide highly porous structure and appropriate pore size for initial cell attachment and proliferation and thereby enable the exchange of nutrients. Composite nanofibers consisting of silk and hydroxyapatite nanoparticles (HAp) (NPs) had been considered as an excellent choice due to their efficient biocompatibility and bone-mimicking properties. To prepare these nanofiber composites, it requires the use of acidic solutions which have serious consequences on the nature of both silk and HAp NPs. It is ideal to create these nanofibers using aqueous solutions in which the physicochemical nature of both materials can be retained. However, to create those nanofibers is often difficult to obtain because of the fact that aqueous solutions of silk and HAp NPs can precipitate before they can be ejected into fibers during the electrospinning process. In this work, we had successfully used a three-way stopcock connector to mix the two different solutions, and very shortly, this solution is ejected out to form nanofibers due to electric fields. Different blend ratios consisting HAp NPs had been electrospun into nanofibers. The physicochemical aspects of fabricated nanofiber had been characterized by different state of techniques like that of FE-SEM, EDS, TEM, TEM-EDS, TGA, FT-IR, and XRD. These characterization techniques revealed that HAp NPs can be easily introduced in silk nanofibers using a stopcock connector, and this method favorably preserves the intact nature of silk fibroin and HAp NPs. Moreover, nanofibers obtained by this strategy were tested for cell toxicity and cell attachment studies using NIH 3 T3 fibroblasts which indicated non-toxic behavior and good attachment of cells upon incubation in the presence of nanofibers.

No MeSH data available.


Related in: MedlinePlus