Colloids and Surfaces A: Physicochem. Eng. Aspects 395 (2012) 94–99 Contents lists available at SciVerse ScienceDirect Colloids and Surfaces A: Physicochemical and Engineering Aspects journa l h omepa g e: www.elsevier.com/locate/colsurfa Characterization and antibacterial properties of Ag NPs loaded nylon-6 nanocomposite prepared by one-step electrospinning process Bishweshwar Pant a , Hem Raj Pant a,b , Dipendra Raj Pandeya c , Gopal Panthi a , Ki Taek Nam d , Seong Tshool Hong c , Cheol Sang Kim a,e , Hak Yong Kim d,∗ a Department of Bionano system Engineering, Chonbuk National University, Republic of Korea b Department of Engineering Science and Humanities, Pulchowk Campus, Tribhuvan University, Nepal c Department of Microbiology and Immunology, Chonbuk National University, Republic of Korea d Department of Organic Materials and Fiber Engineering, Chonbuk National University, Republic of Korea e Division of Mechanical Design Engineering, Chonbuk National University, Republic of Korea a r t i c l e i n f o Article history: Received 23 September 2011 Received in revised form 9 November 2011 Accepted 7 December 2011 Available online 16 December 2011 Keywords: Electrospinning Nanofibers Ag NPs Reduction Antibacterial a b s t r a c t A facile one-step approach to fabricate nylon-6 nanofibers decorated with silver nanoparticles by electro- spinning has been reported. The method did not need post-treatments and could be carried out at ambient room condition. It employed the electrospinning solvents [formic acid and methoxy poly(ethylene gly- col)] as a reducing agent for the conversion of AgNO 3 into Ag NPs during the solution preparation for electrospinning. The resultant Ag/nylon-6 hybrid nanofibers showed a smooth fibrous structure, with controlled size of Ag NPs uniformly dispersed throughout the nylon-6 matrix. The size of Ag NPs could be controlled by regulating the standing time duration of electrospinning solution. These hybrid nylon- 6 composite nanofibers exhibited antibacterial activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Therefore, the obtained nylon-6 nanofibrous mats loaded with Ag NPs can be used in different areas such as wound dressing, water filters etc. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Electrospinning is regarded as a simple and versatile technique for fabricating continuous fibers not only from polymers [1,2] but also from inorganic [3] and hybrid (organic–inorganic) compounds [4–6]. Recently, unique mechanical, electrical, chemical and optical properties have been achieved by decorating polymer fibers with metal nanoparticles (NPs) [7–10], which have different applications in a wide range of areas, e.g., filtration, protective clothing, catalysis, sensors, energy storage, biomaterials [6,9,10]. Amounts, size and proper decoration of metal NPs on the polymer matrix can effec- tively control the properties of these hybrid nanocomposites [11]. Recently, the utilization of electrospun polymer nanofibers with embedded silver NPs has attracted much attention mainly due to its antimicrobial activities [12–15]. Silver NPs show antibacterial activity toward germs on contact without release of toxic biocides [16,17]. Therefore, the antimicrobial properties of Ag NPs can be considered as non-toxic and environmental friendly material in biomedical application. The Ag NPs filled polymeric materials have to release the Ag ions to a pathogenic environment continuously in ∗ Corresponding author. Tel.: +82 632702351; fax: +82 632704249. E-mail address: khy@jbnu.ac.kr (H.Y. Kim). order to be efficacious [18]. The loading of Ag NPs on biocompati- ble polymer matrix was usually achieved either by reducing AgNO 3 into Ag NPs in polymer solution prior to electrospinning [19] or by using post treatments process, such as UV radiation, thermal or chemical reduction of the electrospun composite fibers [20]. Mix- ing of Ag NPs in polymer solution prior to electrospinning causes the aggregation of NPs, whereas post treatment reduction of Ag NPs on electrospun mats is time and energy consuming. Furthermore, the reducing agents used for post treatment are toxic. Therefore, a facile and feasible approach to attain good dispersion of Ag NPs in the polymer fibers is highly desirable. Here, we demonstrated a novel one-step route for uniformly assembling the in situ formed Ag NPs by solvent reduction of polymer solution on the surface of electrospun nylon-6 nanofibers driven by either coordination bond or interfacial hydrogen bond formation. In particular, we have investigated the effect of the standing time duration of polymeric solution containing AgNO 3 on the assembly of Ag NPs on nylon-6 nanofibers by influencing the combined reduction efficiency of formic acid (HCOOH) and methoxy poly(ethylene glycol) (MPEG) (used as solvent). Formic acid only acts as reducing agent whereas MPEG can act as both reducing as well as capping agent. In case of nylon-6 electrospun nanofibers obtained from the solution of short standing time, the attachment of Ag NPs on the surface of nylon-6 fibers may cause 0927-7757/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.colsurfa.2011.12.011