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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

Schematic presentation of the used electrospinning setup. The inset image shows the assembly of the stopcock connector used to mix silk/PEO and HAp/PEO colloidal solutions. The inset shows the photograph of the three-way connector used in this study.
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Figure 2: Schematic presentation of the used electrospinning setup. The inset image shows the assembly of the stopcock connector used to mix silk/PEO and HAp/PEO colloidal solutions. The inset shows the photograph of the three-way connector used in this study.

Mentions: The electrospinning of nanofibers was carried out using an electrospinning instrument purchased from eS-robot®, ESR-200R2D, NanoNC, Geumcheon-gu, Seoul, Korea. For fabricating the pristine nanofibers by electrospinning, the silk/PEO solutions were injected using 10 ml disposable plastic syringe fitted with a 22needle gauge (0.7 mm OD × 0.4 mm ID). The syringes were mounted on an adjustable stand, and flow rate of 0.8 mL/min was adjusted using a multi-syringe pump to keep the solution at the tip of the needle without dripping. The high power supply capable of generating +30 kV and −30 kV for positive and negative voltages was used to eject out the nanofibers from the needle tip. A metallic wire originating from the positive electrode (anode) with an applied voltage of +20 kV was connected to the needle tip through alligator clips, and a negative electrode (cathode) with an applied voltage of −1 kV was attached to the flat bed metallic collector [24,25]. The syringes were mounted in the parallel plate geometry at 45° downtilted from the horizontal baseline, and 12 to 15 cm was kept as the working distance (between the needle tip and collector). The as-spun nanofibers were crystallized by incubating the samples in 100%, 70%, 50%, and 0% of ethanol for 10 min each, and samples were frozen and kept for lyophilization overnight. For the electrospinning of nanofibers containing HAp NPs, a three-way stopcock connector was used to mix the silk/PEO and HAp/PEO solutions (Figure 2). As illustrated in Figure 2, from one side, silk/PEO solution was supplied to one of the openings of the stopcock, and from another side, HAp/PEO colloid was supplied to another opening of the stopcock to let solutions blend properly (i.e., silk/PEO + HAp/PEO) and eventually flow towards the needle tip due to the continuous flow rate applied from the syringe pump. All the electrospinning parameters were kept the same as to the electrospun pristine silk nanofibers; the expected flow rate was reduced to 0.4 mL/min, from both syringe pumps, so as to have the final flow rate of 0.8 mL/min (i.e., the flow rate kept for jet formation in case of pristine nanofibers). Furthermore, the nanofibers were treated in the same way for crystallization and freeze drying as aforementioned in case of pristine silk nanofibers.


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)

Schematic presentation of the used electrospinning setup. The inset image shows the assembly of the stopcock connector used to mix silk/PEO and HAp/PEO colloidal solutions. The inset shows the photograph of the three-way connector used in this study.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Schematic presentation of the used electrospinning setup. The inset image shows the assembly of the stopcock connector used to mix silk/PEO and HAp/PEO colloidal solutions. The inset shows the photograph of the three-way connector used in this study.
Mentions: The electrospinning of nanofibers was carried out using an electrospinning instrument purchased from eS-robot®, ESR-200R2D, NanoNC, Geumcheon-gu, Seoul, Korea. For fabricating the pristine nanofibers by electrospinning, the silk/PEO solutions were injected using 10 ml disposable plastic syringe fitted with a 22needle gauge (0.7 mm OD × 0.4 mm ID). The syringes were mounted on an adjustable stand, and flow rate of 0.8 mL/min was adjusted using a multi-syringe pump to keep the solution at the tip of the needle without dripping. The high power supply capable of generating +30 kV and −30 kV for positive and negative voltages was used to eject out the nanofibers from the needle tip. A metallic wire originating from the positive electrode (anode) with an applied voltage of +20 kV was connected to the needle tip through alligator clips, and a negative electrode (cathode) with an applied voltage of −1 kV was attached to the flat bed metallic collector [24,25]. The syringes were mounted in the parallel plate geometry at 45° downtilted from the horizontal baseline, and 12 to 15 cm was kept as the working distance (between the needle tip and collector). The as-spun nanofibers were crystallized by incubating the samples in 100%, 70%, 50%, and 0% of ethanol for 10 min each, and samples were frozen and kept for lyophilization overnight. For the electrospinning of nanofibers containing HAp NPs, a three-way stopcock connector was used to mix the silk/PEO and HAp/PEO solutions (Figure 2). As illustrated in Figure 2, from one side, silk/PEO solution was supplied to one of the openings of the stopcock, and from another side, HAp/PEO colloid was supplied to another opening of the stopcock to let solutions blend properly (i.e., silk/PEO + HAp/PEO) and eventually flow towards the needle tip due to the continuous flow rate applied from the syringe pump. All the electrospinning parameters were kept the same as to the electrospun pristine silk nanofibers; the expected flow rate was reduced to 0.4 mL/min, from both syringe pumps, so as to have the final flow rate of 0.8 mL/min (i.e., the flow rate kept for jet formation in case of pristine nanofibers). Furthermore, the nanofibers were treated in the same way for crystallization and freeze drying as aforementioned in case of pristine silk nanofibers.

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