Silk Fibroin Polyvinyl Alcohol Research Articles

Silk fibroin/polyvinyl alcohol composite film loaded with antibacterial AgNP/polydopamine-modified montmorillonite; characterization and antibacterial properties

In this study, a kind of nanocomposite film was fabricated via combining silk fibroin, polyvinyl alcohol (SF/PVA) and AgNP/polydopamine-modified Montmorillonite (AgNP/PDA-Mt). The structural characteristics and properties of the SF/PVA/AgNP/PDA-Mt nanocomposites films were identified using X-ray diffraction (XRD), Thermal gravimetric analyzer (TGA), Fourier transform infrared spectroscopy (FTIR), EDS-mapping analyses and Scanning electron microscope (SEM). The results indicated enhanced thermal performance of SF/PVA/AgNP/PDA-Mt nanocomposites with increased AgNP/PDA-Mt weight. The nanocomposite film exhibited excellent antibacterial activity against E. coli and S. aureus. The 2 % SF/PVA/AgNP/PDA-Mt film showed the highest zone of inhibition with an average inhibition circle diameter of 26.1 mm against E. coli and 20.61 mm against S. aureus. Cytotoxicity test results indicated that the nanocomposites films were biocompatible with L929 cells with a 100 % survival rate, which can be considered as one of the advantages of new nanocomposites films. These findings suggest that SF/PVA/AgNP/PDA-Mt films have potential clinical applications in wound dressing and antibacterial biomedical applications.

Preparation and characterization of silk fibroin-polyvinyl alcohol (PVA) blend films for food packaging materials

The present research work deals with the characterization of blend films obtained by mixing silk fibroin (SF) [Bombyx mori CSR4] and Poly Vinyl Alcohol (PVA) in various proportions, considering its potential applicability in the food-packaging industry. The structural, chemical, mechanical and thermal property as well as surface morphologies of blend films were investigated by X-ray diffraction (XRD), Fourier transform InfraRed spectroscopy, universal testing machine, thermogravimetric analysis, differential scanning calorimetry and scanning electron microscope. The SEM results clearly show the proper miscibility of SF and PVA molecules to give a uniform nice surface to the blend films. The physical and thermal properties of the blend films are enhanced significantly compared to the pure silk fibroin films, with more than 100 percentage elongation at break for few blend films. The SF-PVA blend films are more flexible and thermally stable, and hence a good candidate for food packaging material.

Transdermal delivery of interleukin-12 gene targeting dendritic cells enhances the anti-tumour effect of programmed cell death protein 1 monoclonal antibody.

ABSTRACTRecent studies have suggested that the anti-tumour effect of the programmed cell death protein 1 monoclonal antibody (aPD-1) depends on the expression of interleukin-12 (IL-12) by dendritic cells (DCs). Since DCs are abundant in skin tissues, transdermal delivery of IL-12 targeting DCs may significantly improve the anti-tumour effect of aPD-1. In this study, a novel mannosylated chitosan (MC)-modified ethosome (Eth-MC) was obtained through electrostatic adsorption. The Eth-MC loaded with plasmid containing the IL-12 gene (pIL-12@Eth-MC) stimulated DCs to express mature-related molecular markers such as CD86, CD80, and major histocompatibility complex-II in a targeted manner. The pIL-12@Eth-MC was then mixed with polyvinyl pyrrolidone solution to make microspheres using the electrospray technique, and sprayed onto the surface of electrospun silk fibroin-polyvinyl alcohol nanofibres to obtain a PVP-pIL-12@Eth-MC/silk fibroin-polyvinyl alcohol composite nanofibrous patch (termed a transcutaneous immunization (TCI) patch). The TCI patch showed a good performance on transdermal drug release. Animal experiments on melanoma-bearing mice showed that topical application of the TCI patches promoted the expression of IL-12 and inhibited the growth of tumour. Furthermore, combined application of the TCI patch and aPD-1 showed a stronger anti-tumour effect than aPD-1 monotherapy. The combination therapy significantly promoted the expression of IL-12, interferon-γ and tumour necrosis factor-α, the infiltration of CD4+ and CD8+ T cells into tumour tissues, and thus promoted the apoptosis of tumour cells. The present study provides a convenient and non-invasive strategy for improving the efficacy of immune checkpoint inhibitor therapy. This study was approved by the Institutional Animal Care and Use Committee at Donghua University (approval No. DHUEC-NSFC-2020-11) on March 31, 2020.

Transcutaneous Tumor Vaccination Combined With aPD-1 Treatment Produces a Synergistic Antitumor Effect

Transcutaneous immunization (TCI) has the advantages of safety, high efficiency, non-invasiveness and convenient use. The basis for the realization of TCI is that skin tissue is rich in dendritic cells (DCs) which are the most powerful antigen presenting cells. DCs also play a key role in tumor immunotherapy, which provides a huge imagination for the application of TCI to tumor treatment. In this study, a novel transdermal tumor vaccine (TTV) delivery system was developed based on the electrospun silkfibroin-polyvinyl alcohol (SF-PVA) nanofibrous patch loaded with surface modified ethosome (Eth). Mannosylated PEI (PEIman) was used to modify Eth, giving the new carrier (termed Eth-PEIman) the ability to simultaneously load polypeptide antigens and oligonucleotide adjuvants and transdermal targeted DCs delivery. With TRP2 peptide as antigen (encapsulated in Eths) and oligodeoxynucleotides containing unmethylated CpG motifs (absorbed in PEIman) as adjuvant, the TTV-loaded patches (TTVP) significantly inhibited the growth of melanoma in mouse model. Moreover, the combined application of the TTVP and anti-programmed death-1 monoclonal antibody (aPD-1) produced a synergistic anti-tumor effect, resulting in a much stronger anti-tumor effect, which may be due to the infiltration of more CD4+ and CD8+ T cells in the tumor tissues. The application of TTVP also increased the expression of IL-12, which may be part of the mechanism of synergistic anti-tumor effect between the TTVP and aPD-1. These results suggest that the combination of the TTVP and immune checkpoint blockers could be an effective strategy for tumor treatment. Our work provides a noninvasive and convenient way for improving the efficacy of immune checkpoint blocking therapy as well as prevention of some family hereditary malignancies.

Physicochemical and Antibacterial Characterization of Nanofibrous Wound Dressing from Silk Fibroin-polyvinyl Alcohol- Elaeagnus Angustifolia Extract

The herbal drug incorporated nanofibers with potential accelerating wound healing has become a promising wound dressing to treat wounds. The present research aimed to study the effects of adding different amounts of Elaeagnus Angustifolia (EA) extract on physical, mechanical, and biological properties of silk fibroin-polyvinyl alcohol (SF-PVA) nanofibers. Thus, different electrospun mats were made by changing the SF to the EA ratio. The successful incorporation of EA in SF-PVA nanofibers was confirmed by Fourier transform infrared spectroscopy (FTIR). No obvious change was observed in the mean fiber diameter except for EA/SF ratio 1:3. Also, mechanical properties results showed that the ultimate tensile strength of samples dropped from 9±0.8 MPa to 2.50±0.03 MPa with decreasing SF amount. The in vitro release studies indicated that the fickian diffusion controlled the EA release profile and it was faster in the nanofibers containing more EA. Furthermore, the addition of EA into the nanofibrous dressings improved their antioxidant activity as well as antibacterial activity against both gram-positive (S. aureus) and gram- negative (E. coli) bacteria. Cell viability was also measured using fibroblast cells cultured on prepared dressings and results proved that the higher amounts of EA have a significant impact on cell viability. These findings suggest the advantages of EA as an additive to regulate cell behavior and for skin tissue regeneration.

Type I collagen peptides and nitric oxide releasing electrospun silk fibroin scaffold: A multifunctional approach for the treatment of ischemic chronic wounds.

Biomimetic nanofibrous scaffolds targeting multiple dysfunctional processes provide a multi-pronged strategy to restore functions and regenerate the damaged tissue. This study investigates a strategy of combining a regenerative component, Type I collagen Peptide (CP), along with a nitric oxide donor, S-Nitrosoglutathione (GSNO), in the form of nanofibrous scaffold to address the non-healing diabetic ulcer. Silk Fibroin-Polyvinyl alcohol (SF-PVA) nanofibrous scaffold is used as a carrier for delivering functional moieties. The developed nanofibrous electrospun mats (SF-PVA, CP-SF-PVA, and CP-GSNO-SF-PVA) showed continuous, bead-less and randomly oriented fibers with highly porous morphology. The in vitro biocompatibility was assessed by MTT assay, DAPI-Rhodamine 123 and FITC-Phalloidin imaging studies. CP-GSNO-SF-PVA nanofibrous scaffold showed a high degree of cell attachment, spreading of F-actin with viable cell morphology and appreciable inter-cellular connection. Thus the study showed that the proliferation of fibroblast cells are mainly facilitated by the presence of collagen peptide in the nanofibrous matrix. Griess assay demonstrated immediate release of NO for a day from the developed multifunctional scaffold. These results demonstrate the in vitro efficacy of CP-GSNO and indicate the opportunity of CP-GSNO-SF-PVA nanofibrous scaffold for the treatment of ischemic non-healing ulcers.

Hybrid chitosan-ZnO nanoparticles coated with a sonochemical technique on silk fibroin-PVA composite film: A synergistic antibacterial activity

The hybrid chitosan-ZnO nanoparticles (C@ZnO NPs) are synthesized and coated on Silk fibroin-polyvinyl alcohol (SF-PVA) composite film by a sonochemical coating process. These are systematically studied for their synergistic antibacterial activity and reported. The coated composite films show the excellent antibacterial activity against Gram-positive and Gram-negative bacteria. The composite films are characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) studies. The specific surface area and porosity are studied by Brunauer-Emmett-Teller (BET) analysis under nitrogen gas adsorption. The swelling degree, mechanical property and cell viability study of coated and uncoated composite films are investigated. The results showed that the specific surface area, porosity, swelling degree, and mechanical property of coated composite films increased with increasing the concentrations of C@ZnO NPs on SF-PVA composite film. Cell viability study confirmed the cytocompatible nature of all the C@ZnO NPs coated composite films. Thus, obtained properties of composite films reveal the potential of this material which can be used as antibacterial wound dressing applications.

Electrospun SF/PVA Nanofiber Filters for Highly Efficient PM $_{2.5}$ Capture

Particulate matter (PM) air pollution is associated with various adverse health effects. Heavy outdoor air pollution, especially smog, has significantly impacted the living quality of residential environments. Here, we report the fabrication of silk fibroin/polyvinyl alcohol (SF/PVA) nanofiber air filters for the filtration of PM pollution using the electrospinning technique. Silk fibroin is a type of protein fibers, which is widely available with excellent environmental sustainability, and PVA is commonly used for continuous nanofiber fabrication. Our results showed that the PM $_{2.5}$ removal efficiency of the SF/PVA filter was 99.11 ${\bf \pm }$ 0.24%, which was about 10% higher than that of the pure PVA filter under the same pressure drop of 50 Pa. In a 24-h filtration test, the filtration efficiency of this composite SF/PVA filter remained at a high value of 98.97% after 24 h. The results indicate the superior filtration performance of the SF/PVA nanofiber air filter, which holds a great promise in PM pollution prevention.

ZnO nanoparticle-embedded silk fibroin–polyvinyl alcohol composite film: a potential dressing material for infected wounds

A highly effective composite film based on ZnO NPs, silk fibroin and PVA for an infected wound.

FTIR imaging, a useful method for studying the compatibility of silk fibroin-based polymer blends

As in other polymer blends, the phase behavior of silk fibroin (SF) blends with other polymers is thought to be important for their related properties. Here we used FTIR imaging to study the phase behavior of three silk protein-based polymer blends, silk fibroin/chitosan (SF/CS) blend, silk fibroin/sodium alginate (SF/SA) blend, and silk fibroin/polyvinyl alcohol (SF/PVA) blend. FTIR images of the films prepared from these polymer blends indicated that the SF/CS blend was compatible, the SF/SA blend was partially compatible, and the SF/PVA blend was incompatible. The results accord with the conclusions from the conventional analysis methods like SEM, DSC, and DTMA reported in the literature. Moreover, we show that FTIR images of the blends can provide additional useful information on the composition of the individual components, and the conformation of SF at defined locations with a spatial resolution of 4 μm. Therefore, we believe FTIR imaging is a useful technique to better understand both the chemical and physical properties of silk protein-based polymer blends, and other kinds of polymer blends.