A high molecular weight silk fibroin scaffold that resists degradation and promotes cell proliferation.

The regulation of the biodegradation rate of 3D-regenerated silk fibroin scaffolds and the avoidance of premature collapse are important concerns for their effective applications in tissue engineering. In this study, bromelain, which is specific to sericin, was used to remove sericin from silk, and high molecular weight silk fibroin was obtained after the fibroin fibers were dissolved. Afterwards, a 3D scaffold was prepared via freeze-drying. The Sodium dodecyl sulfate-polyacrylamide gel electrophoresis results showed that the average molecular weight of the regenerated silk fibroin prepared by using the bromelain-degumming method was approximately 142.2 kDa, which was significantly higher than that of the control groups prepared by using the urea- and Na2 CO3 -degumming methods. The results of enzyme degradation in vitro showed that the biodegradation rate and internal three-dimensional structure collapse of the bromelain-degumming fibroin scaffolds were significantly slower than those of the two control scaffolds. The proliferation activity of human umbilical vein vascular endothelial cells inoculated in bromelain-degumming fibroin scaffolds was significantly higher than that of the control scaffolds. This study provides a novel preparation method for 3D-regenerated silk fibroin scaffolds that can effectively resist biodegradation, continuously guide cell growth, have good biocompatibility, and have the potential to be used for the regeneration of various connective tissues.

Analysis of the antimicrobial potential of sericin-coated silver nanoparticles against human pathogens.

The antibacterial activity of synthetic antimicrobial agents is well known, but most of them have several side effects and are effective against selective microbes. Recently, major concern for the microbiologists is to investigate for some stable, non-toxic, cheap, and eco-friendly antimicrobial agents with a wide range of bactericidal potential. A cost-effective and environmentally friendly alternate has been proposed in the form of green synthesized nanoparticles. The Present study was designed to fabricate sericin-coated silver nanoparticles (S-AgNPs) using sericin as stabilizer and reductant of silver ions and their antibacterial potential was evaluated at various concentrations and temperatures (8, 40, and 50°C). Antimicrobial activities were assessed by the agar well diffusion method. Antibacterial activity of S-AgNPs was measured at different concentrations (1-6 mg/ml) whereas; antifungal activity was tested at 5-20 mg/ml of S-AgNPs. Nanoparticles were characterized by UV-visible spectrophotometer, Fourier transform infrared spectroscopy, and scanning electron microscopy. These nanoparticles significantly subdued the growth of Clostridium difficile (18.7 ± 0.9 mm), Proteus mirabilis (12.3 ± 0.3 mm) and Bacillus licheniformis (10.7 ± 0.9 mm) and Aspergillus flavus (18.7 ± 2.0 mm), Mucor mycetes (13 .0 ± 1.5 mm), Candida albicans (15.3 ± 0.3 mm) and Aspergillus niger (10.0 ± 0.6 mm). S-AgNPs were stable at all temperatures and the maximum growth inhibition was found at 8°C for all pathogenic strains. We concluded that the S-AgNPs could be a potential candidate to inhibit the growth of bacterial and fungal pathogens at a wide range of environmental conditions like temperature. In various biomedical applications including antimicrobial and wound dressings, S-AgNPs can be used in the future to treat various bacterial and fungal infections.

Potential of antimicrobial topical gel with synthesized biogenic silver nanoparticle using Rhodomyrtus tomentosa leaf extract and silk sericin.

OBJECTIVE: Silver nanoparticles synthesized using Rhodomyrtus tomentosa leaf extract and silk sericin were used to functionalize carbopol 940 gel for topical applications. RESULTS: UV-vis spectra presented surface plasmon resonance at 426 nm, transmission electron microscopy revealed that nanoparticles were spherical with an average size of 25-50 nm. X-ray diffraction presented crystalline silver nanoparticles with zeta potential of ≈ - 30 mV. FTIR spectra showed a reduction of silver nitrate indicated by the shift in -OH at 2958 cm-1. The silver nanoparticle demonstrated broad-spectrum antimicrobial activity against Gram-positive, Gram-negative and fungi with MIC ranging between 0.26 and 2.10 µg mL-1, respectively. MIC of hydrogel ranged between 1.05-2.10 µg mL-1 with cell viability of 89%. Spreadability and extrudability of gel were 9.3 ± 0.85 s and 19.85 ± 0.03%, respectively with first order of fickian diffusion. CONCLUSIONS: The silver nanoparticle gel exhibited an effective antimicrobial property, hence can be exploited for topical applications.

Silk fibres exhibiting biodegradability & superhydrophobicity for recovery of petroleum oils from oily wastewater.

Present study reports superhydrophobic-oleophilic, environment-friendly, & biodegradable silk material derived from Bombyx mori silkworm, for practical oil-water separation and oil recovery applications. In this study, raw silk fibers were degummed using water and Na2CO3 (at 100 °C), for removal of outer gummy sericin protein layer, which was confirmed using FTIR & FE-SEM analysis. The water & Na2CO3 degummed silk fibers showed superhydrophobicity with water contact angles (WCA) of 153° & 158°, respectively, demonstrating Wenzel & Cassi-Baxter states. Degummed silk fibers showed superoleophilicity (OCA∼0°) towards petroleum oils like Petrol, Diesel, & Engine oil. The water & Na2CO3 degummed silk fibers showed oil-water separation efficiencies of 95 % & 87.5 %, respectively. Both degummed silk fibers showed more than 50 % efficiency till 10 separation cycles. Further, raw & degummed silk fibers showed an environmental biocompatibility, by their biodegradation under in-house developed biotic de-compost culture consisting of biodegrading micro-organisms. Their analysis showed that biotic de-compost culture rendered biodegradation weight loss of 11 % and 18 %, respectively, in 35 days. Successive results showed that, degummed silk fibers can be effectively utilized for practical oil-water separation, and further, they can be environmentally biodegraded, thereby mitigating their waste generation and disposal problem.

Tamanu oil potentiated novel sericin emulgel of levocetirizine: repurposing for topical delivery against DNCB-induced atopic dermatitis, QbD based development and in vivo evaluation.

The present study was aimed at preparing and evaluating levocetirizine (LCZD) loaded emulgel containing tamanu oil and sericin for atopic dermatitis (AD) therapy. The emulgel envisaged topical delivery of LCZD utilising natural antioxidants for superior therapeutic outcomes when compared with other conventional therapy. Tamanu oil based microemulsion (ME) was optimised utilising Box-Behnken design (BBD). The OPT-ME displayed globule size 379.5 ± 2.33 nm, polydispersity index 0.284, drug loading 0.41 ± 0.01% w/w, entrapment efficiency 94.34 ± 2.11% w/w and drug release 86.24 ± 4.90% respectively over a period of 24 h. The optimised formulation (OPT-ME) was further incorporated into sericin gel to form emulgel (LSE). In vivo pharmacodynamic studies revealed enhanced therapeutic potential of emulgel in terms of reduced scratching frequency and erythema score when compared with conventional gel. The superior therapeutic potential was further witnessed through histopathological and biochemical studies. The emulgel can be an alternative appropriate dosage form for the treatment of AD.

Silk sericin induced fabrication of reduced graphene oxide and its in-vitro cytotoxicity, photothermal evaluation.

Nowadays, photothermal agents have attained considerable attention in nanomedicine for the treatment of cancer after chemotherapy, surgery, biological therapy and radiotherapy. In this work, we showed a sericin-based, simple approach for synthesis of sericin functionalized reduced graphene oxide (SRGO) with low cytotoxicity and photo thermal efficiency. During the synthesis, the GO is deoxygenated in situ and functionalized by sericin, a low-cost, silk protein and concurrently forms SRGO. The subsequent SRGO disperse well in water with higher biocompatibility because of the decoration of sericin on graphene sheets. The prepared SRGO exhibited a good photothermal capacity with near-infrared laser irradiation (808 nm) for efficient killing of HeLa cells. Further, the synthesized SRGO could act as a promising material for photo thermal therapy applications in future.

In vitro culture medium (IVC) supplementation with sericin improves developmental competence of ovine zygotes.

This study was carried out to investigate the effects of supplementation of potassium simplex optimized medium (KSOM-aa) with various sericin concentrations (0, 0.1, 0.5, 1 and 2.5%) on ovine zygotes. The results indicate that the supplementation of oocyte in vitro culture medium with optimal concentration of sericin (0.1 and 0.5%) may have beneficial effects on developmental competence of in vitro-derived ovine embryos.

A novel poly(γ-glutamic acid)/silk-sericin hydrogel for wound dressing: Synthesis, characterization and biological evaluation.

A novel multifunctional poly(γ-glutamic acid)/silk sericin (γ-PGA/SS) hydrogel has been developed and used as wound dressing. The physical and chemical properties of the γ-PGA/SS gels were systemically investigated. Furthermore, these γ-PGA/SS gels have been found to promote the L929 fibroblast cells proliferate, and in the in vivo study, significant stimulatory effects were also observed on granulation and capillary formation on day 9 in H-2-treated wounds, indicating that this new complex hydrogel could maintain a moist healing environment, protect the wound from bacterial infection, absorb excess exudates, and promote cell proliferation to reconstruct damaged tissue. Considering the simple preparation process and excellent biological property, this γ-PGA/SS hydrogel might have a wide range of applications in biomedical and clinical areas.