Hydroxyethyl cellulose for spontaneous synthesis of antipathogenic nanostructures: (Ag & Au) nanoparticles versus Ag-Au nano-alloy Hanan B. Ahmed a, ⁎, Mariana A. Attia a , Farida M.S.E. El-Dars a , Hossam E. Emam b, ⁎ a Chemistry Department, Faculty of Science, Helwan University, Ain-Helwan, Cairo 11795, Egypt b Department of Pretreatment and Finishing of Cellulosic Based Textiles, Textile Industries Research Division, National Research Centre, Scopus Affiliation ID 60014618, 33 EL Buhouth St., Dokki, Giza 12622, Egypt abstract article info Article history: Received 4 November 2018 Received in revised form 17 January 2019 Accepted 20 January 2019 Available online 22 January 2019 The current approach represents a controllable strategy for studying the antipathogenic effects against selected bacterial strains and fungi for silver nanoparticles and gold nanoparticles versus their bimetallic nano-alloys spontaneously prepared by the same technique. Spontaneous ingraining of silver and gold based monometallic and bimetallic nano-objects was carried out by employing organic polymer of hydroxyethyl cellulose which was presumed to play the dual role of nanogenerator and surfactant, via seed mediated growth technique. Rev- olution of UV–Visible spectroscopy revealed that, the characteristic surface plasmon resonance (SPR) peak for Ag-Au bimetallic nano-alloy was detected at 480–495 nm and X-ray diffraction patterns confirmed the successive role of HEC in generation of bimetallic nanostructures. Transmission electron microscope (TEM) and zetasizer data were detected for clarifying the effect of the polymer concentration, addition sequencing of metal salts in reaction liquor, and reaction temperature on the morphological features and size distribution of the as- produced bimetallic nano-alloy. Referring to zetasizer analyses and TEM micrographs, small sized (10.7 nm) Ag-Au bimetallic nano-alloy was successfully produced by employing HEC as nano-producer. All the generated bimetallic nano-objects exhibited high stability with PdI ranged in 0.268–0.560. The mechanism for generation of nanostructures was confirmed according to FT-IR, 1HNMR and13CNMR spectra. © 2019 Elsevier B.V. All rights reserved. Keywords: HEC Spontaneous growth Ag-Au bimetallic nano-alloy Antipathogenic effect 1. Introduction In this century, researches in nanoscience concepts have received tremendous consideration, due to its interdisciplinary applications in the various purposes such like; catalysis, biomedicine, fuel cells, mag- netic data storage and energy technology [1]. Nanostructures with par- ticle size in range of 10–100 nm have unique activities like high surface area, quantum property, adsorption/releasing properties, and exhibited by high potentials in multifunctional applications [2]. Metallic nano- structures (MNPs) are specifically considered due to their unique prop- erties and different applications [3]. Recent reports approved that, the size, topographical features, diffusibility and physicochemical charac- ters of metallic nanostructures are basically affected by the synthesis methodology [4–13]. Numerous of recent approaches were interested in the investigation of new strategies for controlling the properties and consequently the application of metallic nanostructures [14]. More- over, conventional synthesis procedures for manufacturing metallic nanostructures were found to consume chemicals and energy, and caused different environmental risks [15], in addition to, they are gener- ally of slow kinetics which rendered it to produce undesirably enlarged particles [16–18]. Therefore, the awareness of investigating alterna- tively simple synthesis techniques becomes the main objective in nano- technology researches [19].One of the different techniques reported for synthesizing metallic nanostructures, the wet chemical method, which has approved to be the most relevant method, due to its relative sim- plicity, affordability and high percentage of the required yield [14–17]. Some of recent reports were especially considered with the synthe- sis of bimetallic Au-AgNPs due to its surface plasmon resonance (SPR) peak which is mainly observed in the range of 410–520 nm [20,21]. Ag-Au nanostructures are advantageous due to their precise composi- tion and high surface activity, where, it integrates the physical and chemical reactivity of both nanometals, in addition to its unique optical [22,23], electronic [24], and catalytic properties [25]. In addition to, size controlled bimetallic nanostructures were reported to be capable of act- ing as auto-fluorescent [26,27] and biosensors rather than the separated nanometals [28], Therefore, the synthesis of size controlled Ag-Au bime- tallic nanostructures becomes one of the great challenges in the recent reports. Several methods have been reported for manufacturing of Au- Ag nano-alloy, including laser ablation [29,30], phase transfer [31], di- gestive ripening [32], co-reduction of Au and Ag salts [33,34], and International Journal of Biological Macromolecules 128 (2019) 214–229 ⁎ Corresponding authors. E-mail addresses: hananbasiony@gmail.com (H.B. Ahmed), hossamelemam@yahoo.com (H.E. Emam). https://doi.org/10.1016/j.ijbiomac.2019.01.093 0141-8130/© 2019 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect International Journal of Biological Macromolecules journal homepage: http://www.elsevier.com/locate/ijbiomac