Fabrication and Characterization of Conductive Conjugated Polymer‐Coated Antheraea mylitta Silk Fibroin Fibers for Biomedical Applications

Abstract

Conductive polymers are interesting materials for a number of biological and medical applications requiring electrical stimulation of cells or tissues. Highly conductive polymers (polypyrrole and polyaniline)/Antheraea mylitta silk fibroin coated fibers are fabricated successfully by in situ polymerization without any modification of the native silk fibroin. Coated fibers characterized by scanning electron microscopy confirm the silk fiber surface is covered by conductive polymers. Thermogravimetric analysis reveals preserved thermal stability of silk fiber after coating process. X-ray diffraction of degummed fiber diffraction peaks at around 2θ = 20.4 and 16.5 confirms the preservation of the β-sheet structure typical of degummed silk II fibers. This phenomenon implies that both polypyrrole and polyaniline chains form interactions with peptide linkages in degummed fiber macromolecules, without significantly disrupting protein assembly. Fourier transform infrared spectroscopy of coated fibers indicates hydrogen bonding and electrostatic interactions exist between silk fibroin macromolecules and conductive polymers. Resulting fibers display good conductive properties compared to corresponding conjugated polymers. In vitro analysis (live/dead assay) of the behavior of human immortalized keratinocytes (HaCaTs) on coated fibers demonstrates improved cell-adhesive properties and viability after polymers coating. Hence, polypyrrole- and polyaniline-coated A. mylitta silk fibers are suitable for application in cell culture and for tissue engineering, where electrical conduction properties are required.

Titanium dioxide-polyaniline/silk fibroin microfiber sensor for pork freshness evaluation

“…Compared with SFF, PANI/SFF and TiO2-PANI/SFF show fairly large shifts in position of diffraction peak, confirming that the interaction of polyaniline with the peptide linkages in SFF macromolecular chains [40]. According to the previous work [40,42,43], hydrogen-bonding interactions between peptide linkages and hydrogen atom on nitrogen atoms of PANI are considered to be main interactions to anchor the PANI on SFFs while the electrostatic attraction may play a secondary role.…”

Conductive Biomaterials as Bioactive Wound Dressing for Wound Healing and Skin Tissue Engineering

“…Degummed silk fibroin (SF) is a natural protein fiber and has been extensively used as wound dressing [ 70 ]. GH et al developed a simple strategy of in situ polymerization of pyrrole and aniline on SF fibers [ 161 ]. PPy and PANI were coated on SF by forming interactions with peptide linkages while mostly preserving protein assembly.…”

Conductive Polymeric-Based Electroactive Scaffolds for Tissue Engineering Applications: Current Progress and Challenges from Biomaterials and Manufacturing Perspectives

“…Silk fiber (SF) coated with PPy and PANI resulted in a significant improvement in the electrical properties of the scaffold. Measurement of conductivity of pristine silk fibroin fibers is 1 × 10 −11 S/cm, the bulk conductivity of pure PPY is 1.3 ± 0.1 × 10 −5 S/cm, and the pure PANI conductivity is 0.8 ± 0.1 × 10 −4 S/cm [ 155 ]. In contrast, PPY/SF and PANI/SF-coated exhibited conductivities of 2.2 ± 0.1 × 10 −5 S cm −1 and 1.6 ± 0.1 × 10−4 S cm −1 , respectively.…”

“…Tests on HaCaT cells showed that the cells adhered to the PPY-coated SF surface and were more effective at PANI. In addition, good cytocompatibility was also shown by PPY/SF and PANI/SF coated [ 155 ]. Another coating using nanometer-scale PPy was applied via in situ chemical polymerization method on the surface of electrospun polycaprolactone-gelatin (PCL-Gel) nanofibers [ 156 ].…”