Silk Fibroin Membrane Research Articles

Regenerated silk fibroin membranes as separators for transparent microbial fuel cells

In recent years novel applications of bioelectrochemical systems are exemplified by phototrophic biocathodes, biocompatible enzymatic fuel cells and biodegradable microbial fuel cells (MFCs). Herein, transparent silk fibroin membranes (SFM) with various fibroin content (2%, 4% and 8%) were synthesised and employed as separators in MFCs and compared with standard cation exchange membranes (CEM) as a control. The highest real-time power performance of thin-film SFM was reached by 2%-SFM separators: 25.7 ± 7.4 μW, which corresponds to 68% of the performance of the CEM separators (37.7 ± 3.1 μW). Similarly, 2%-SFM revealed the highest coulombic efficiency of 6.65 ± 1.90%, 74% of the CEM efficiency. Current for 2%-SFM reached 0.25 ± 0.03 mA (86% of CEM control). Decrease of power output was observed after 23 days for 8% and 4% and was a consequence of deterioration of SFMs, determined by physical, chemical and biological studies. This is the first time that economical and transparent silk fibroin polymers were successfully employed in MFCs.

Recirculating peritoneal dialysis system using urease-fixed silk fibroin membrane filter with spherical carbonaceous adsorbent

The chronic kidney disease (CKD) patients are undergoing continuous ambulatory peritoneal dialysis (CAPD). However, there are some constraints, the frequent exchange of the dialysate and limitation of outside activity, associated with CAPD remain to be solved. In this study, we designed the wearable artificial kidney (WAK) system for peritoneal dialysis (PD) using urease-immobilized silk fibroin (SF) membrane and polymer-based spherical carbonaceous adsorbent (PSCA). We evaluated this kit's removal abilities of uremic toxins such as urea, creatinine, uric acid, phosphorus, and β2-microglobulin from the dialysate of end-stage renal disease (ESRD) patients in vitro. The uremic toxins including urea, creatinine, uric acid, and phosphorus were removed about 99% by immobilized SF membrane and PSCA filter after 24 h treatment. However, only 50% of β2-microglobulin was removed by this filtering system after 24 h treatment. In vivo study result shows that our filtering system has more uremic toxins removal efficiency than exchanged dialysate at every 6 h. We suggest that recirculating PD system using urease-immobilized SF membrane with PSCA could be more efficient than traditional dialysate exchange system for a WAK for PD.

Copper-surrogated galvanic displacement of silver dendrite imprinted on flexible and transparent silk fibroin membrane as a SERS-active substrate and sub-dividable catalyst

By employing copper grid as a surrogate agent, we present a facial, reagent-free and cost-effective approach to imprint the exquisite silver dendroid nanostructures on flexible silk fibroin membrane, which double roles as both optical enhancers and catalytic-active sites over many chemical reactions. Unlike the conventional rigid substrates, this hybrid Ag/protein composite exhibits many previous-inaccessible properties of flexibility, transparency, biocompatibility, molecular permeability and optical manipulation. The galvanic displacement was facilitated by a high pressure uv-lamp illumination (365 nm), shortening the dendroid growth time to be within a few minutes. The resulting substrate was characterized by microscopic image, revealing a decent 3D Ag dendrite architecture and interpenetrated crystal network, which arguably enlarged the entire surface area and keenly regulated the optical/electric property of fibrillated protein film. The underlying principle of copper-initiated silver reduction and growth of crystal structure was discoursed and verified with in-situ spectroscopic interrogation. Moreover, our comprehensive study supports that sub-dividable substrate enables to perform catalytic reaction under a wide range of conditions. This exploration renders a thrust to expand biopolymeric membrane into a wide breadth of applications of bendable devices through chemical modifications, exhaustively and economically.

Porous and nonporous silk fibroin (SF) membranes wrapping for Achilles tendon (AT) repair: Which one is a better choice?

Two types of silk fibroin (SF) membranes were developed for tendon repair: porous and nonporous SF membranes. The objective of this study was to compare the efficiency of these two films according to the ability of tendon regeneration using a rat Achilles tendon (AT) rupture suture wrapping model. The in vitro tests were conducted, and theSF membranes were proved to be with ultimate-biodegradability, good-biocompatibility and without toxicity. In vivo, 12 Sprague Dawley rats were used to create a rat AT rupture suture model wrapped by SF membranes. They were randomly divided into six groups. The results revealed that the nonporous SF membrane wrapping group was shown to reduce the inflammatory effect and induce the proliferation of fibroblast-like cells at one week and four weeks post-operatively. After four weeks, the nonporous SF membrane wrapping group exhibited more organized collagen structures and had increased expression of tendon repair proteins. Hence, our nonporous SF membrane improved the efficacy of tendon regeneration by decreasing inflammatory cells, growing fibroblast-like cells, and promoting extracellular matrix production. Nonporous SF membrane can, therefore, be regarded as a better functional membrane for tendon repair. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: 00B: 000-000, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 733-740, 2019.

Fabrication of a Urea Biosensor for Real-Time Dynamic Fluid Measurement.

In this study, a portable urea sensor that monitors the urea concentration in flow conditions was fabricated. We propose an electrochemical sensor that continually measures the urea concentration of samples flowing through it at a constant flow rate in real time. For the electrochemical sensing, a porous silk fibroin membrane with immobilized urease was mounted in a polydimethylsiloxane (PDMS) sensor housing. The fabricated urea sensor elicited linear current–concentration characteristics in the clinically significant concentration range (0.1–20 mM) based on peritoneal dialysis. The sensor maintained the linear current–concentration characteristics during operation in flow conditions.

Effect of silk degumming on the structure and properties of silk fibroin

Two different silk fibroin samples were obtained by the Na2CO3 and urea degumming methods of silk fibers in the same fiber dissolution system, respectively. The molecular weight and viscosity of the fibroin samples were analyzed by the methods of SDS-PAGE, rheological, and etc. Then, different silk fibroin membranes (SFMs) and blank microspheres were prepared, and the effects of degumming methods on the silk fibroin were studied via analyzing the differences of SFMs and blank microspheres of the two samples. The experimental results showed that the viscosity of fibroin solution was positively correlated with its molecular weight. The fibroin prepared by the Na2CO3 degumming was lower than the one prepared by the urea degumming in the viscosity of the fibroin solution under the same mass concentration. Degumming with Na2CO3 exhibited the obvious effects on the thermal stability and mechanical properties of SFM, tensile strength decreased almost 10% and breaking elongation reduced more than 50%. Blank microspheres prepared from silk fibroin degummed with the different methods showed different particle sizes and its distribution. The microspheres prepared from silk fibroin degummed with the Na2CO3 had the smaller particle sizes and more concentrated distribution compared with those with the urea.

Preparation of a multifunctional fibroin-based biomaterial via laccase-assisted grafting of chitooligosaccharide

Chitooligosaccharide (COS) has the characteristic of antioxidant and antibacterial effects. To improve the properties of silk fibroin (SF), COS was enzymatically grafted onto SF membranes using a laccase from Trametes versicolor. d-Glucosamine hydrochloride (GAH) and p-hydroxyphenylacetamide (PHAD), as the model compound of COS and tyrosine residues in SF were utilized to disclose the grafting mechanism, respectively. The data from UPLC-TQD and GPC analysis implied that laccase might catalyze the oxidation of PHAD and led to the formation of self-polymerized products. FTIR and 1H NMR results verified the occurrence of the laccase-assisted reactions between COS and PHAD. For the fibroin samples with different treatments, incubation with laccase alone led to remarkable increase in the molecular weight of SF, mainly owing to the efficient self-crosslinks of the fibroin chains. For the COS-grafted SF membrane, there was no obvious change in the thermal behavior, while the antioxidant and antibacterial properties were evidently improved when compared to that of the untreated. Meanwhile, biocompatibility of the COS grafted SF membrane was acceptable according to the cell viability of NIH/3T3 cells. The present work provides a novel method for preparation of the multifunctional fibroin-based biomaterials.

Silk Fibroin‐Based Fibrous Anal Fistula Plug with Drug Delivery Function

The aim of this work is to develop a drug-loaded silk fibroin fibrous membrane (DSFM) that can be attached to the surface of an anal fistula plug to improve the treatment of Crohn's disease (CD). Curcumin (CUR) and 5-aminosalicylic acid (5-ASA)-loaded silk fibroin (SF) membranes are coaxially electrospun onto the surface of a braided silk filament plug. The membranes show a predominant structure of random coil and silk I conformation. The concentration of CUR/5-ASA (weight ratio of 1/1) in the SF solution is optimized to 0.4, 0.9, and 1.9 wt%. The morphologies, secondary structures, and in vitro drug release properties of the membranes are examined. Sectional images of fibers in the membranes show core-shell structures. The coaxial electrospinning process does not alter the chemical characteristics of the drugs. The dual-drugs encapsulated in the membranes are released in a steady and sustainable manner, and the cumulative release rate is improved by the increased drug loading. The membranes exhibit no cytotoxicity, thereafter increase the viability of human fibroblasts on the DSFMs. These SF membranes with core-shell structure and functional encapsulation of CUR and 5-ASA should be useful for further studies toward the treatment of CD.

Poly(ethylene glycol)-modified silk fibroin membrane as a carrier for limbal epithelial stem cell transplantation in a rabbit LSCD model

BackgroundLimbal epithelial stem cells (LESCs) play important roles in corneal epithelial homeostasis and regeneration, and damage to the limbus will lead to limbal stem cell deficiency (LSCD), with conjunctivalization and even visual impairment. Cultured LESCs have been used for ocular surface reconstruction, and silk fibroin (SF) membranes have shown potential as a substrate for LESC cultivation. Both culture methods and the carriers of LESCs affect outcomes following LESC transplantation.MethodsRabbit LESCs were cultured from tissue explant, single cell-suspension, and cell cluster culture methods. Ratios of p63α and/or ABCB5-positive LESCs, differentiated corneal epithelial cells (CK12 staining), and corneal tight junction formation (Claudin-1 staining) were examined to choose the most applicable LESC cultures. SF membranes were prepared and modified by 400-Da poly(ethylene glycol) (PEG). The characteristics of stem cells and normal corneal differentiation of LESCs cultured on PEG-modified SF membranes were further examined by immunofluorescence staining and flow cytometric analysis. LESCs cultured on PEG-modified SF membranes (LESC/SF grafts) and PEG-modified SF membranes (SF grafts) were transplanted onto rabbit corneas with total LSCD. New blood vessels, corneal epithelial defects, and cornea clarity were examined after transplantation. Furthermore, corneal epithelial thickness, stromal thickness, and the percentage area of CK12-positive corneal epithelium were quantified 4 months after transplantation.ResultsTissue explant and single cell-suspension cultures harvested more p63α and/or ABCB5-positive LESCs, generated more CK12-positive corneal epithelial cells, and formed more corneal tight junctions than cell cluster cultures. Prepared PEG-modified SF membranes were transparent, flexible, and sturdy enough for surgical manipulation. LESCs cultured on PEG-modified SF membranes maintained characteristics of stem cells and normal corneal differentiation. LESC/SF grafts inhibited new blood vessels and rescued corneal epithelial defects in the rabbit total LSCD model. In addition, LESC/SF grafts repopulated the limbus and increased corneal epithelial thickness, stromal thickness, and the area percentage of CK12-positive corneal epithelium.ConclusionsLESCs from tissue explant and single cell-suspension cultures were more applicable corneal epithelial cells for ocular surface reconstruction. LESC/SF grafts repaired corneal epithelial defects and reversed LSCD, and PEG-modified SF membranes were suitable to be a carrier for LESC transplantation.

Constructing an Anisotropic Triple-Pass Tubular Framework within a Lyophilized Porous Gelatin Scaffold Using Dexamethasone-Loaded Functionalized Whatman Paper To Reinforce Its Mechanical Strength and Promote Osteogenesis.

In bone tissue engineering (BTE), most of the currently developed scaffolds still lack the ability to demonstrate high porosity and high mechanical strength simultaneously or the ability to maintain bioactivity and sustained release of loaded biofactors. In this work, we constructed an anisotropic triple-pass tubular framework within a lyophilized porous GEL scaffold using FP, which was prepared by coating DEX-covered Whatman paper (WP) using the silk fibroin (SF) membrane with β-sheet conformation. This novel structural design endowed the functionalized paper frame (FPF)/scaffold implant high porosity, high mechanical strength, and sustained DEX delivery capability. Specifically, its porosity was as high as 88.2%, approximating that of human cancellous bone. The pore diameters of the implant ranged from 50 to 350 μm with an average pore diameter of 127.7 μm, indicating proper pore sizes for successful diffusion of essential nutrients/oxygen and bone tissue-ingrowth. Owing to the construction of double-network-like structure, the FPF/scaffold implant demonstrated excellent mechanical properties both in dry (174.7 MPa in elastic modulus and 14.9 MPa in compressive modulus) and wet states (59.0 MPa in elastic modulus and 3.3 MPa in compressive modulus), indicating its feasibility for in vivo implantation. Besides, the FPF/scaffold implant exhibited long-term DEX releasing behavior (over 50 days) with constant release rate in phosphate buffered saline (PBS). Murine osteoblasts MC3T3-E1 cultured in the porous FPF/scaffold implant had excellent viability. Furthermore, the cells cocultured with the FPF/scaffold implant showed positive proliferation, osteogenic differentiation, and calcium deposition. Twenty-eight days after implantation, extensive osteogenesis was observed in the rats treated with the FPF/scaffold implants. The anisotropic triple-pass tubular framework of the FPF/scaffold implant demonstrates structural similarities to the long bone. Therefore, this novel FPF/scaffold implant could be a better alternative for long bone defect repair.

Rational design of a stable, effective, and sustained dexamethasone delivery platform on a titanium implant: An innovative application of metal organic frameworks in bone implants

Endowing titanium implants with the capability of delivering dexamethasone in a sustained and controlled manner to promote osseointegration and osteogenesis has become an emerging field. However, most of the currently developed dexamethasone/titanium implants are far from satisfactory because of some inherent defects. In this work, we constructed a stable, effective, and sustained dexamethasone delivery platform on titanium disc by immobilizing dexamethasone@zeolitic imidazolate framework-8 nanoparticles into the micrometer-scale artificial etch pits on titanium substrate using methanol-induced regenerated silk fibroin membrane encapsulation. In addition, the titanium substrate was aminated and covalent interactions were established between the titanium substrate and the silk fibroin membrane through genipin crosslinking. Briefly, owing to the synergistic barrier effect of the zeolitic imidazolate framework-8 shell and the silk fibroin membrane, the silk fibroin-dexamethasone@zeolitic imidazolate framework-8-titanium could release dexamethasone in a controlled manner over 30days. Moreover, the pit walls together with the silk fibroin membrane protected the nanoparticles from detaching from the titanium substrate in the case of mechanical wear. The covalent interactions between the silk fibroin membrane and the titanium substrate prevented the silk fibroin membrane from self-peeling from the titanium substrate in a moist environment. In vitro cell culture indicated that the as-prepared titanium disc had good cytocompatibility with MC3T3-E1 cells. Furthermore, the cells cultured on the titanium disc demonstrated higher differentiation, calcium deposition, and expression of osteogenic genes than the cells cultured on the silk fibroin-zeolitic imidazolate framework-8-titanium and pristine titanium. In this work, dexamethasone was utilized as a drug model and could be replaced by other osteogenic drugs or growth factors. Thus, we believed that our design philosophy could inspire future research work on the development of Ti implants.

Limbal stromal cells derived from porcine tissue demonstrate mesenchymal characteristics in vitro

Limbal stromal cells (LSCs) from the human ocular surface display mesenchymal stromal cell characteristics in vitro. In this study, we isolated cells from the porcine limbal stroma (pLSCs), characterised them, and evaluated their ability to support angiogenesis and the culture of porcine limbal epithelial stem cells (pLESCs). The isolated cells adhered to plastic and grew in monolayers in vitro using serum-supplemented or serum-free medium. The pLSCs demonstrated expression of CD29, and cross-reactivity with anti-human CD45, CD90, CD105, CD146, and HLA-ABC. However, expression of CD105, CD146 and HLA-ABC reduced when cultured in serum-free medium. PLSCs did not undergo adipogenic or osteogenic differentiation, but differentiated towards the chondrogenic lineage. Isolated cells were also co-cultured with human umbilical vein endothelial cells (HUVECs) in star-shaped Poly(ethylene glycol) (starPEG)-heparin hydrogels to assess their pericyte capacity which supported angiogenesis networks of HUVECs. PLSCs supported the three dimensional HUVEC network for 7 days. The isolated cells were further growth-arrested and evaluated as feeder cells for pLESC expansion on silk fibroin membranes, as a potential carrier material for transplantation. PLSCs supported the growth of pLESCs comparably to murine 3T3 cells. In conclusion, although pLSCs were not completely comparable to their human counterpart, they display several mesenchymal-like characteristics in vitro.

Glycerol-plasticised silk membranes made using formic acid are ductile, transparent and degradation-resistant

Regenerated silk fibroin membranes tend to be brittle when dry. The use of plasticisers such as glycerol improve membrane ductility, but, when combined with aqueous processing, can lead to a higher degradation rate than solvent-annealed membranes. This study investigated the use of formic acid as the solvent with glycerol to make deformable yet degradation-resistant silk membranes. Here we show that membranes cast using formic acid had low light scattering, with a diffuse transmittance of less than 5% over the visible wavelengths, significantly lower than the 20% transmittance of aqueous derived silk/glycerol membranes. They had 64% β-sheet content and lost just 30% of the initial silk weight over 6h when tested with an accelerated enzymatic degradation assay, in comparison the aqueous membranes completely degraded within this timeframe. The addition of glycerol also improved the maximum elongation of formic acid derived membranes from under 3% to over 100%. They also showed good cytocompatibility and supported the adhesion and migration of human tympanic membrane keratinocytes. Formic acid based, silk/glycerol membranes may be of great use in medical applications such as repair of tympanic membrane perforation or ocular applications where transparency and resistance to enzymatic degradation are important.

Electrospun Nanofibrous Silk Fibroin Membranes Containing Gelatin Nanospheres for Controlled Delivery of Biomolecules.

Development of novel and effective drug delivery systems for controlled release of bioactive molecules is of critical importance in the field of regenerative medicine. Here, oppositely charged gelatin nanospheres are incorporated into silk fibroin nanofibers through a colloidal electrospinning technique. A novel fibrous nano-in-nano drug delivery system is fabricated without the use of any organic solvent. The distribution of fluorescently labeled gelatin A and B nanospheres inside the nanofibers can be fine-tuned by simple adjustment of the weight ratio between the nanospheres and the relative feeding rate of core and shell solutions containing nanospheres by using single and coaxial nozzle electrospinning, respectively. Incorporation of vancomycin-loaded gelatin B nanospheres into the silk fibroin nanofibrous membranes results in a more sustained release of vancomycin, compared to the gelatin nanospheres free membranes. In addition, these membranes exhibit excellent and prolonged antibacterial effects against Staphylococcus aureus. Moreover, these membranes support the attachment, spreading, and proliferation of periodontal ligament cells. These results suggest that the beneficial properties of gelatin nanospheres can be exploited to improve the biological functionality of electrospun nanofibrous silk fibroin membranes.

Regulating the gaps between folds on the surface of silk fibroin membranes via LBL deposition for improving their biomedical properties

Silk fibroin (SF) has become a promising biomaterial in guided bone regeneration (GBR). In an attempt to modify the size of the gaps on the surface of SF barrier membrane and improve its antibacterial activity, biological and mechanical properties, positively charged Lysozyme (LY)-Collagen Type-I (COL) composites and negatively charged SF were introduced to the negatively charged surface of SF substrates utilizing the electrostatic layer-by-layer (LBL) self-assembly technique. The morphology, chemical structures and element content of the LBL structured membranes were investigated. The results suggested that LY and COL were successfully assembled and the gaps between the folds on the surface of the membranes became smaller gradually with the increase of coated film numbers. Besides, the content of β-sheets of the membranes increased after deposition, which indicated the improvement of their mechanical properties. Moreover, the results of the measurement of immobilized LY and antibacterial assay not only revealed that the enzymatic catalysis and antibacterial activity of the samples enhanced with the increase of coated bilayer numbers but also implied that LBL modified membranes had better antibacterial activity when LY–COL was on the outermost layer. Furthermore, CCK-8 assay certified both SF membrane and LBL structured membranes could facilitate cell growth and proliferation, and the introduction of COL could further promote this ability. Finally, cell attachment and morphology examination provided intuitional evidence that SF membrane and LBL modified membranes have excellent biocompatibility.

Removal of the heavy metal ions from aqueous solution using modified natural biomaterial membrane based on silk fibroin

Water-insoluble silk fibroin (WSF) membrane was prepared by co-blending and interaction of fibroin and silane coupling agent. A novel Schiff base with a chelating group, 3,5-bis-{2-hydroxyphenyl-5- [(2-sulphate-4- sulphatoethylsulphonyl-azobenzol) methylene amino]} benzoic acid (BHSABA), was applied to modify WSF membrane. The morphological structure and surface element analysis of WSF and its modified membrane (MWSF) were investigated by scanning electron microscopy (SEM) and energy dispersive spectrometer (SEM-EDS). The sorption behavior of MWSF membrane for six metal ions, Cu(II), Co(II), Ni(II), Cr(III), Pb(II) and Cd(II), were measured. MWSF membrane had the significantly selective sorption for Pb(II) and Cd(II) metal ions and the removal percentage being 82% and 56%, respectively. The adsorption kinetics of MWSF membrane for Cd(II) was analyzed by the pseudo-first-order and pseudo-second-order equations. The adsorption removal process for Cd(II) metal ion was in line with the pseudo-second-order model. MWSF membrane as bioabsorbent has potential application for removal heavy metal ions from the aqueous solution.

Grafting of tyrosine-containing peptide onto silk fibroin membrane for improving enzymatic reactivity

During enzymatic modifications of silk fibroins, the accessibility of tyrosinases to the reactive sites was limited owing to the steric hindrance of tyrosine residues in the fibroin proteins. To improve the reactivity of silk fibroin, a tyrosine-containing peptide (TyrP) was covalently grafted onto the fibroin surfaces using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). Enzymatic oxidation of the modified fibroins was subsequently carried out with a mushroom tyrosinase, followed by coupling of e-polylysine (e-PL) with the generated o-quinone residues of silk fibroins. The efficacy of grafting reaction was examined by means of SDS-PAGE and amine acid analysis. The results indicated EDC treatment might cause the direct self-crosslinks of silk fibroins and TyrP-bridged cross-links of fibroin molecules as well, which led to a noticeable increase in the molecular weight of fibroin proteins. TyrP-grafted fibroins displayed higher reactivity compared to the untreated, and more e-PL was bonded to the fibroin surfaces when incubating with tyrosinase, resulting in improved wettability and mechanical property. The presented work offers an efficient alternative for the enzymatic modification of the fibroin-based materials with tyrosinase.

Silk fibroin membrane used for guided bone tissue regeneration

With the aim to develop a novel membrane with an appropriate mechanical property and degradation rate for guided bone tissue regeneration, lyophilized and densified silk fibroin membrane was fabricated and its mechanical behavior as well as biodegradation property were investigated. The osteoconductive potency of the silk fibroin membranes were evaluated in a defect rabbit calvarial model. Silk fibroin membrane showed the modulated biodegradable and mechanical properties via ethanol treatment with different concentration. The membrane could prevent soft tissue invasion from normal tissue healing, and the amounts of new bone and defect closure with silk fibroin membrane were similar to those of commercially available collagen membrane.

Guiding bone regeneration using hydrophobized silk fibroin nanofiber membranes

Biocompatible barrier membranes with both hydrophobic and hydrophilic surface properties provide critical backup for guided regeneration at localized bone defects without soft tissue invasion. As a surface modified functional barrier, saturated fluorocarbon (CF4)-immobilized nanofibrous silk fibroin (SF) membranes were fabricated by electrospinning for a fibrous non-woven mat, water vapor treatment for insolubilization, and followed by CF4 gas plasma treatment for top surface hydrophobization. Plasma-treated SF nanofiber membranes maintained a non-woven mat structure without shrinkage and deformation in a five-month biodegradation test. From in vivo rabbit cranium perforation model, nanofibrous SF membranes prevented soft tissue invasion and facilitated volumetric bone regeneration compared with the control groups. New bone ingrowth in bone defects at 4 and 8 weeks after surgery was visualized by trichrome staining. Medical application of fluorocarbon-immobilized nanofibrous SF barrier membranes could be one of the practical approaches for guided bone regeneration. Open image in new window

Fabrication of Ascorbic Acid Biosensor Based on Coupling Polyethylene Glycol Modified Silk Fibroin Membrane onto Glassy Carbon Electrode

Nowadays biosensors have been extensively used in a wide variety of applications especially in clinical works and food industry. In this work, a specific ascorbic acid (AA) biosensor was developed by immobilizing ascorbate oxidase (ASOD) on a polyethylene glycol (PEG) modified silk fibroin (SF) membrane then coupling to the glassy carbon electrode (GCE). The SF-PEG-ASOD membrane provided the highest enzyme activity in phosphate buffer at pH 5. As being the electrode, the SF-PEG-ASOD modified GCE displayed the highest response when it is operated under the condition of 0.40 mg/L of ASOD in phosphate buffer at pH 5. This biosensor provided both good linearity (r2 = 0.999 in the range of 1.0-10.0 mM) and sensitivity with short response time (26s). It also exhibited good anti-interference ability with the storage time of 5 days without changing its initial response.