Nanofibers For Biomedical Applications Research Articles

New plasma-assisted polymerization/activation route leading to a high density primary amine silanization of PCL/PLGA nanofibers for biomedical applications

Surface modification of hydrophobic nanofibers (NFs) to introduce cell-interactive chemical functionalities remains a challenge in biomedical applications. This study presents a novel three-step plasma-based method for synthesizing coatings with improved chemical selectivity compared to conventional plasma polymers. The process involved hexamethyldisiloxane (HMDSO) plasma polymerization followed by helium plasma activation, both performed in a medium-pressure dielectric barrier discharge. Scanning electron microscopy analysis demonstrated that the plasma-based steps did not cause damage to the NFs. X-ray photoelectron spectroscopy (XPS) and water contact angle measurements revealed the formation of a hydrophilic silanol-rich layer after HMDSO plasma polymerization and helium plasma activation. In the third step, (3-aminopropyl)triethoxysilane (APTES) was grafted onto the plasma polymer to introduce primary amine groups onto the surface, as confirmed by XPS. Although the APTES-based layer exhibited partial removal when exposed to aqueous environments, a stable aminated layer remained on the NF surface, which significantly enhanced Schwann cell responses compared to untreated and HMDSO-based coated NFs. This enhancement was confirmed through fluorescent imaging using live-dead staining, immunostaining, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. These coatings with a high selectivity in their chemical functionality (amines, or other functionalities via silanization agent selection), offer a promising surface functionalization approach for tissue engineering scaffolds.

Potential Loading of Virgin Coconut Oil into Centrifugally‐Spun Nanofibers for Biomedical Applications

AbstractVirgin coconut oil (VCO) has become a multifunctional material for biomedical applications due to its remarkable health benefits. The use of VCO for biomedical applications has seen tremendous growth over recent years, triggering researchers to develop various approaches for VCO utilization. Nanofibers‐based structure offers promising properties to encapsulate VCO, enhancing its performance and broadening its application in the medical field. Studies of VCO‐loaded polymeric nanofibers for biomedical applications are currently gradually rising. Recently, in nanofibers technology, centrifugal jet spinning (CJS) offers cost‐efficient and higher production rates to yield nanofibers compared to the other methods. This review summarizes recent advances of VCO for biomedical applications. Comprehensive suggestions for encapsulating VCO into nanofibers using the CJS technique are also provided. Highlights of future challenges in utilizing the CJS technique to produce VCO‐loaded nanofibers for biomedical applications are also elaborated.

Emulsion electrospinning of sodium alginate/poly(ε-caprolactone) core/shell nanofibers for biomedical applications

Electrospun nanofibers have shown great potential as drug vehicles and tissue engineering scaffolds. However, the successful encapsulation of multiple hydrophilic/hydrophobic therapeutic compounds is still challenging. Herein, sodium alginate/poly(ε-caprolactone) core/shell nanofibers were fabricated via water-in-oil emulsion electrospinning. The sodium alginate concentration, water-to-oil ratio, and surfactant concentration were optimized for the maximum stability of the emulsion. The results demonstrated that an increasing water-to-oil ratio results in more deviation from Newtonian fluid and leads to a broader distribution of the fibers' diameters. Moreover, increasing poly(ε-caprolactone) concentration increases loss and storage moduli and increases the diameter of the resulting fibers. The nanofibers' characteristics were investigated by scanning electron microscopy, transmission electron microscopy, confocal laser scanning microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and water contact angle measurements. It was observed that using an emulsion composition of 10% (w/v) PCL and a water-to-oil ratio of 0.1 results in smooth, cylindrical, and uniform core/shell nanofibers with PCL in the shell and ALG in the core. The in vitro cell culture study demonstrated the favorable biocompatibility of nanofibers. Overall, this study provides a promising and trustworthy material for biomedical applications.

Antibacterial Ag containing core‐shell polyvinyl alcohol‐poly (lactic acid) nanofibers for biomedical applications

AbstractCore‐shell‐structured polyvinyl alcohol (PVA)‐poly (lactic acid) (PLA) nanofibers combining the hydrophilic trait of PVA and the biocompatibility of PLA were produced using coaxial electrospinning. This allowed the incorporation of AgNO3 in the PVA core of the distinct fibers as shown through transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) showed relatively uniform and bead‐free fibers with smooth surfaces. Ag‐containing fibers show significantly decreased diameters compared with Ag‐free samples as a result of the increased conductivity of the spinning solutions with increasing amounts of AgNO3. In a postsynthetic treatment, the AgNO3 was reduced forming silver nanoparticles (Ag NPs). Ag NPs of 45 to 90 nm size were located in the PVA core but also on the surface of the core‐shell fibers and as individual, agglomerated, and polymer‐coated particles of 100‐200 nm. Powder X‐ray diffraction (PXRD), energy dispersive X‐ray spectroscopy (EDX), and UV‐vis absorption spectroscopy confirmed the increasing amounts of Ag in the core‐shell fibers when using increasing amounts of AgNO3 in the spinning solutions. The antibacterial activity of the nanofiber mats against two prokaryotes Escherichia coli (Gram‐negative) and Staphylococcus aureus (Gram‐positive) increased with increasing amounts of Ag, as expected and produces inhibition zones of 1 to 2 mm.

Biological behavior of the curcumin incorporated chitosan/poly(vinyl alcohol) nanofibers for biomedical applications.

Electrospun composite scaffolds show high ability to be used in regenerative medicine and drug delivery, due to the nanofibrous structure and high surface area to volume ratio. In this study, we used nanofibrous scaffolds fabricated by chitosan (CS), poly(vinyl alcohol) (PVA), carbopol, and polycaprolactone using a dual electrospinning technique while curcumin (Cur) incorporated inside of the CS/PVA fibers. Scaffolds were fully characterized via scanning electron microscopy, water contact angle, tensile measurement, hydration, protein adsorption, and wrinkled tests. Furthermore, viability of the buccal fat pad-derived mesenchymal stem cells (BFP-MSCs) was also investigated using MTT assay for up to 14 days while cultured on these scaffolds. Cell cycle assay was also performed to more detailed evaluation of the stem cells growth when grown on scaffolds (with and without Cur) compared with the culture plate. Results demonstrated that Cur loaded nanofibrous scaffold had more suitable capability for water absorption and mechanical properties compared with the scaffold without Cur and it could also support the stem cells viability and proliferation. Cur release profile showed a decreasing effect on BFP-MSCs viability in the initial stage, but it showed a positive effect on stem cell viability in a long-term manner. In general, the results indicated that this nanofibrous scaffold has great potential as a delivery of the Cur and BFP-MSCs simultaneously, and so holds the promising potential for use in various regenerative medicine applications.

Electrospinning Based Functional Nanofibers for Biomedical Applications

Electrospinning Based Functional Nanofibers for Biomedical Applications

Potential of Electrospun Graphene Oxide-Gelatin Composite Nanofibers for Biomedical Applications

Graphene oxide incorporated polymer matrix provides a multifunctional facet due to the reinforcing effect of graphene oxide (GO) with wide range of properties. Nanofibers are fabricated by a versatile technique known as electrospinning. The present study demonstrates the fabrication of gelatin, a protein nanofibers non-covalently functionalized with GO. The effect of GO on gelatin nanofibers in terms of mechanical performance is studied. In order to improve the water resistance of the resulting nanofibers, cross-linking is performed using dextran aldehyde.

Emulsion Electrospinning as an Approach to Fabricate PLGA/Chitosan Nanofibers for Biomedical Applications

Novel nanofibers from blends of polylactic-co-glycolic acid (PLGA) and chitosan have been produced through an emulsion electrospinning process. The spinning solution employed polyvinyl alcohol (PVA) as the emulsifier. PVA was extracted from the electrospun nanofibers, resulting in a final scaffold consisting of a blend of PLGA and chitosan. The fraction of chitosan in the final electrospun mat was adjusted from 0 to 33%. Analyses by scanning and transmission electron microscopy show uniform nanofibers with homogenous distribution of PLGA and chitosan in their cross section. Infrared spectroscopy verifies that electrospun mats contain both PLGA and chitosan. Moreover, contact angle measurements show that the electrospun PLGA/chitosan mats are more hydrophilic than electrospun mats of pure PLGA. Tensile strengths of 4.94 MPa and 4.21 MPa for PLGA/chitosan in dry and wet conditions, respectively, illustrate that the polyblend mats of PLGA/chitosan are strong enough for many biomedical applications. Cell culture studies suggest that PLGA/chitosan nanofibers promote fibroblast attachment and proliferation compared to PLGA membranes. It can be assumed that the nanofibrous composite scaffold of PLGA/chitosan could be potentially used for skin tissue reconstruction.

Encapsulation of Amoxicillin within Laponite-Doped Poly(lactic-co-glycolic acid) Nanofibers: Preparation, Characterization, and Antibacterial Activity

We report a facile approach to encapsulating amoxicillin (AMX) within laponite (LAP)-doped poly(lactic-co-glycolic acid) (PLGA) nanofibers for biomedical applications. In this study, a synthetic clay material, LAP nanodisks, was first used to encapsulate AMX. Then, the AMX-loaded LAP nanodisks with an optimized AMX loading efficiency of 9.76 ± 0.57% were incorporated within PLGA nanofibers through electrospinning to form hybrid PLGA/LAP/AMX nanofibers. The loading of AMX within LAP nanodisks and the loading of LAP/AMX within PLGA nanofibers were characterized via different techniques. In vitro drug release profile, antimicrobial activity, and cytocompatibility of the formed hybrid PLGA/LAP/AMX nanofibers were also investigated. We show that the loading of AMX within LAP nanodisks does not lead to the change of LAP morphology and crystalline structure and the incorporation of LAP/AMX nanodisks does not significantly change the morphology of the PLGA nanofibers. Importantly, the loading of AMX within LAP-doped PLGA nanofibers enables a sustained release of AMX, much slower than that within a single carrier of LAP nanodisks or PLGA nanofibers. Further antimicrobial activity and cytocompatibility assays demonstrate that the antimicrobial activity of AMX toward the growth inhibition of a model bacterium of Staphylococcus aureus is not compromised after being loaded into the hybrid nanofibers, and the PLGA/LAP/AMX nanofibers display good cytocompatibility, similar to pure PLGA nanofibers. With the sustained release profile and the reserved drug activity, the organic/inorganic hybrid nanofiber-based drug delivery system may find various applications in tissue engineering and pharmaceutical science.

Fabrication and morphology control of electrospun poly(γ-glutamic acid) nanofibers for biomedical applications

We report the fabrication of water-stable electrospun γ-polyglutamic acid (γ-PGA) nanofibers with morphology control for biomedical applications. In this study, the processing variables including polymer concentration, flow rate, applied voltage, collection distance, and ambient humidity were systematically optimized to generate uniform γ-PGA nanofibers with a smooth morphology. By changing the trifluoroacetic acid concentration in the electrospinning solution, the diameter of the γ-PGA nanofibers can be controlled within the range of 186–603nm. To render the γ-PGA nanofibers with good water stability, cystamine was employed as a crosslinking agent to amidate the carboxyl groups of γ-PGA. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric assay in conjunction of cell morphology observation reveals that the obtained γ-PGA nanofibers have an excellent biocompatibility to promote the cell adhesion and proliferation. We anticipate that the fabricated electrospun γ-PGA nanofibers with controllable morphology and good water stability may find extensive applications in future development of tissue engineering scaffold materials, drug delivery systems, environmental remediation, and sensing.