Elsevier

Polymer

Volume 193, 10 April 2020, 122338
Polymer

Electrodeposition of poly (vinyl alcohol-co-ethylene) nanofiber reinforced chitosan nanocomposite film for electrochemically programmed release of protein

https://doi.org/10.1016/j.polymer.2020.122338Get rights and content

Highlights

  • The PVA-co-PE/chitosan nanocomposite was successfully constructed via a green and facile electrodeposition method.

  • The nanofiber is confirmed to influence greatly on the film structure and properties.

  • The incorporated nanofiber network confers higher mechanical property and pH-dependent permeation performance to the film.

  • The nanocomposite was proved to be a versatile platform for electrochemically programmed release of protein.

Abstract

Here, we report that chitosan can mediate assembly of poly (vinyl alcohol-co-ethylene) (PVA-co-PE) nanofiber via a green and facile electrodeposition approach, and forming a nanocomposite film with enhanced mechanical property and pH-dependent permeability. Several measurements suggest the film growth (eg. thickness) is linearly correlated to the imposed charge transfer and can be well quantified by using a moving front model. Morphological observations reveal that the nanofibers are evenly distributed throughout of the films and formed with novel fiber/polymer architecture. Swelling ratio and water flux measurements indicate the film permeation property was greatly influenced by the nanofiber contents and environmental pH cues. The incorporated nanofiber leads to a higher protein loading capacity of 1.38 μg/cm2 (eg. Insulin) and allows a sustained release from the confined internal microporous structure over 24 h. In addition, above release behaviors can be programmed according to externally imposed electrical signals. Thus, coupling chitosan-mediated assembly of nanofibers with the electrochemically controlled release system provides great possibilities for multi-functional coatings and drug elution on conductive implants.

Introduction

Chitosan, an amino polysaccharide also known as deacetylated chitin, is the second abundant natural polysaccharide in nature which can be widely found from the shells of crabs and shrimps [1]. In resent year, chitosan has captured much attention for applications ranging from biocompatible coatings to drug delivery systems due to its excellent biocompatibility, biodegradability and low toxicity. Additionally, the versatile pH-dependent solubility, abundant reactive groups (eg. hydroxyl and amino groups) and great film-forming properties make chitosan the most promising natural biopolymers. Therefore, massive efforts have been devoted for the approaches to rapid produce the chitosan-based composites with controllable structures [2] and functions [3], such as direct casting, spraying and filtration, physical or chemical deposition, etc [[4], [5], [6]]. Among these, electrodeposition as one of the most popular versatile approach has been proposed to controllably form a chitosan film on a conducting substrate [7,8]. The short imposed electrical signals can be employed to direct assembly of chitosan and yield hydrogel film with spatially varying structure and properties based on the electrochemical reduction induced pH gradient near the cathode electrode surface [9,10]. Owing to these significant features of electrodeposition, there has been a continuously growing interest in utilizing chitosan biopolymeric coating specifically for improving the biointerface of medical implants.

In our previous study, the use of chitosan and other biopolymeric films from electrodeposition often limited with poor mechanical strength, low entrapment efficiency and sudden release behavior, which significant affect the therapeutic efficacy and long-term application of the film in drug release systems. To address these problems, co-deposition of chitosan with various inorganic materials, eg. 0D materials for the mesoporous silica nanoparticle [11], bioactive glass [12]; 1D materials for the hydroxyapatite [13], carbon nanotubes [14]; 2D materials for the layered double hydroxides [15] and graphene oxide [16] has been proved to be an effective way for enhancing their bioactivity, thermal, mechanical, corrosion resistance and barrier properties. Particularly, nanofiber-based materials with unique one-dimensional nanostructure that always been considered as advanced and effective reinforcing materials due to its large length to diameter ratio, high surface area, large porosity and excellent mass permeability [17,18]. By integrating nanofiber into polymer films, it is possible to obtain better interaction filler matrix, and usually result in a large matrix/filler interfacial area, which changes the molecular mobility, the relaxation behavior, and the consequent thermal and mechanical properties of the polymeric films [19]. Screen et al. have reported the tensile strength and modulus of the Poly (ethylene glycol) (PEG) hydrogel film were significantly improved by incorporating with short fibers of poly (2-hydroxyethyl methacrylate) in the PEG bulk hydrogel matrix [20]. Yingyi Liu et al. have demonstrated that the electrospun nanofibrous membrane also can be integrated onto a microfluidic chip to confer higher protein absorption property for multiple immunoassays [21]. Despite the versatility of electrospinning method and may incorporate most of the nanofiber-based materials, the drawbacks of time-consuming and specific requirement of high-voltage limit its application in industry [22,23]. Thus, a green and versatile approach to allow massive preparation of poly (vinyl alcohol-co-ethylene) (PVA-co-PE) nanofiber has been developed by our group [24,25]. The PVA-co-PE nanofiber was fabricated by using the cellulose acetate butyrate (CAB) as the immiscible matrix through a conventional co-rotating twin-screw extrusion equipment which is able to be prepared in a large scale. The PVA-co-PE as a commercial polymer possessing abundant active hydroxyl groups has been widely applied in the fields ranging from smart wearable devices to electrochemical sensors [[26], [27], [28]]. Therefore, coupling of the PVA-co-PE nanofiber and facial electrodeposition approach with the expectation to the massive production of nanofiber reinforced chitosan nanocomposite films for the industry application.

As illustrated in Scheme 1a, we demonstrate that chitosan can mediate electrodeposition of the PVA-co-PE nanofibers at addressable locations to form a nanocomposite film with specific shape that corresponding to the conductive substrates. In this work, the films with different content of nanofibers were prepared, and the structure and properties of the nanocomposite films were fully discussed. The nanofibers were well incorporated throughout of chitosan film. Importantly, the electrodeposition process was achieved from mild condition and thus allows protein (eg. insulin) to be loaded and then electrochemically guided release from the deposited films (Scheme 1b) indicating the great potential application in drug control release system. In summary, we believe the significant of this work is the broad concept of transducing the electrical signals into multiple biology information: i) supramolecular structural information (eg. complex fiber/polymer architecture); ii) optical information (eg. cumulative release of protein molecules) for the short-term purpose of providing a generic approach to assemble nanocomponents into functional device and long-term bridging the information processing capabilities of electronics and biology.

Section snippets

Materials

Chitosan with a degree of deactylation of 85% (molecular weight 200 kDa) and PVA-co-PE (44% ethylene unit) were purchased from Sigma-Aldrich. CAB (butyryl content 35–39%) was purchased from Acros Chemical Pittsburg, PA, USA. All other reagents were analytical grade and used without further purification.

Preparation of PVA-co-PE nanofibers

In briefly, the PVA-co-PE nanofiber suspensions were prepared following a melt phase separation method according to our previously reported work [29]. Firstly, the blended PVA-co-PE and CAB

Chitosan-mediated electrodeposition of PVA-co-PE nanofiber

In this part, we demonstrate the capability of integrating PVA-co-PE nanofibers onto polymeric film based on chitosan's electrodeposition. Fig. 1a presents a typical SEM image of the PVA-co-PE nanofibers used in our investigation. Insert figure indicates the nanofibers were fabricated with an average diameter of 320 nm and have a broad distribution ranging from 100 to 600 nm. For electrodeposition, various amounts of PVA-co-PE nanofibers were first suspended into a chitosan solution (1 wt%,

Conclusions

In this paper, the PVA-co-PE/chitosan nanocomposite film were successfully constructed via a green and facile electrodeposition method. From the microstructure observations and characterizations, the nanofibers were proved uniform dispersed throughout of the film and formed with a novel fiber/polymer architecture. Several measurements have proved that the nanofiber is confirmed to influence greatly on the film structures and properties. On the one hand, the good fiber-polymer adhesion

CRediT authorship contribution statement

Kun Yan: Conceptualization, Writing - review & editing. Feiyang Xu: Data curation, Writing - original draft. Yongheng Ni: Resources, Data curation. Ke Yao: Resources. Weibing Zhong: Visualization, Software. Yuanli Chen: Visualization.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work has been supported by financial support of National Natural Science Foundation of China (51403166, 51473129, 51603155). We thank “Wuhan Engineering Technology Research Center for Advanced Fibers” providing partial support for materials processing.

References (48)

  • X. Xu et al.

    Cellulose nanofiber-embedded sulfonated poly (ether sulfone) membranes for proton exchange membrane fuel cells

    Carbohydr. Polym.

    (2018)
  • K. Delmar et al.

    Composite chitosan hydrogels for extended release of hydrophobic drugs

    Carbohydr. Polym.

    (2016)
  • M. Rinaudo

    Chitin and chitosan: properties and applications

    ChemInform

    (2007)
  • J. Nie et al.

    Orientation in multi-layer chitosan hydrogel: morphology, mechanism, and design principle

    Sci. Rep.

    (2015)
  • Y. Liu et al.

    Fabrication of antibacterial chitosan-PVA blended film using electrospray technique for food packaging applications

    Int. J. Biol. Macromol.

    (2017)
  • S.H. Teng et al.

    Chitosan/nanohydroxyapatite composite membranes via dynamic filtration for guided bone regeneration

    J. Biomed. Mater. Res.

    (2010)
  • W. Zhen et al.

    Antibacterial and environmentally friendly chitosan/polyvinyl alcohol blend membranes for air filtration

    Carbohydr. Polym.

    (2018)
  • C. Maerten et al.

    Review of electrochemically triggered macromolecular film buildup processes and their biomedical applications

    ACS Appl. Mater. Interfaces

    (2017)
  • J. Li et al.

    Electrobiofabrication: electrically based fabrication with biologically derived materials

    Biofabrication

    (2019)
  • C. Yi et al.

    Characterization of the cathodic electrodeposition of semicrystalline chitosan hydrogel

    Mater. Lett.

    (2012)
  • S. Wu et al.

    Electrical writing onto a dynamically responsive polysaccharide medium: patterning structure and function into a reconfigurable medium

    Adv. Funct. Mater.

    (2018)
  • A.G. Esfahani et al.

    Hierarchical microchannel architecture in chitosan/bioactive glass scaffolds via electrophoretic deposition positive‐replica

    J. Biomed. Mater. Res.

    (2019)
  • A. Molaei et al.

    Electrophoretic deposition of chitosan–bioglass ® –hydroxyapatite–halloysite nanotube composite coating

    Rare Met.

    (2018)
  • Y.Y. Shi et al.

    Electrophoretic deposition of graphene oxide reinforced chitosan–hydroxyapatite nanocomposite coatings on Ti substrate

    J. Mater. Sci. Mater. Med.

    (2016)
  • Cited by (6)

    View full text