اثر همزمانی نانوفیلرهای نقره اکسید گرافین بر عملکرد مهندسی غشاهای نانوسیم پلی الکترولیت Synergistic effect of graphene oxide-silver nanofillers on engineering performances of polyelectrolyte complex nanofiber membranes

INTRODUCTION Polyelectrolyte complex (PEC) represents a novel class of macromolecular materials formed by the association of polycation and polyanion.1 The formation of PEC is mainly driven by the electrostatic attraction although other intra- or inter-molecular forces including hydrogen bonding and van der Waals forces may also play minor roles in the complexation.1 Because PEC generally contains two distinctive polyelectrolytes, PEC offers competitive advantages in its physicochemical properties over either one of its constituent polyelectrolytes. When PEC was fabricated into onedimensional (1D) or two-dimensional (2D) nanostructures, that is, nanofibers, such type of PEC system possessed superior properties including high specific area and porosity compared to its counterparts in other forms.2–4 Recently, PEC nanofibers have been exploited for potential applications in various fields including nanomedicine, environmental technology and drug delivery.2 For instance, Jiang et al. fabricated chitosan/sodium alginate PEC nanofiber membranes as biomaterial scaffolds for potential tissue engineering applications.5 In addition, Meng et al. specifically designed poly(diallyldimethylammonium chloride)/poly(4-styrenesulfonic acid) PEC nanofiber membranes for the use in water purification.6 In the areas of regeneration medicine and food packaging, antibacterial property which is generally absent in conventionally designed PEC nanofibers is highly desirable for combating pathogens and contaminants.7–9 For instance, wound dressing made of PEC nanofiber membranes should possess excellent antibacterial activity to target pathogenic bacteria and to prevent wound infection, leading to the achievement of practical wound healing.10 The limited antibacterial ability of PEC has become a major hurdle for the realization of PEC-based technology in biomedicine. Thus, the design and development of various classes of PEC membranes with enhanced antibacterial properties have attracted the increasing attentions.11–14 In addition, mechanical properties play a vital role in the durability and compliance of PEC nanofiber membranes/scaffolds for long-term biomedical applications in vivo. 15 As such, satisfactory mechanical performance of nanofiber based biomaterial scaffolds are indispensable to the success of tissue regeneration by providing an favorable microenvironment for cell adhesion, proliferation, migration and differentiation.3 Due to high porosity and weak inter-fiber cohesion, PEC nanofiber membranes usually do not meet the basic requirements in the mechanical properties for in vivo implementation.