Antibacterial activity of Ag–Au alloy NPs and chemical sensor property of Au NPs synthesized by dextran

• Published in: Carbohydrate polymers 2014-07, Vol.107, p.151-157
• Main Authors: Bankura, Kalipada, Maity, Dipanwita, Mollick, Md. Masud Rahaman, Mondal, Dibyendu, Bhowmick, Biplab, Roy, Indranil, Midya, Tarapada, Sarkar, Joy, Rana, Dipak, Acharya, Krishnendu, Chattopadhyay, Dipankar
• Format: Article
• Language: English
• Subjects: Ag–Au alloy; Alloys - chemistry; Alloys - pharmacology; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Antimicrobial activity; Applied sciences; Bacteria - drug effects; Chemistry Techniques, Analytical - instrumentation; Colorimetric sensor; Cross-disciplinary physics: materials science; rheology; Dextran stabilized nanoparticles; Dextrans - chemistry; Drug Stability; Exact sciences and technology; Gold - chemistry; Materials science; Metal Nanoparticles - chemistry; Nanoparticles; Nanopowders; Nanoscale materials and structures: fabrication and characterization; Natural polymers; Particle Size; Pesticides - analysis; Pesticides - chemistry; Physicochemistry of polymers; Physics; Silver - chemistry; Starch and polysaccharides; Water - chemistry
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2014.02.047

•Au and Au–Ag alloy nanoparticles are synthesized using dextran.•Nanoparticles are highly stable.•The Au nanoparticles are used as a sensor for detection and estimation of pesticide.•Au–Ag alloy nanoparticles show significant antibacterial activity. Gold and silver–gold alloy nanoparticles with mean diameter of 10nm and narrow size distribution were prepared by reduction of the correspondent metal precursors using aqueous dextran solution which acts as both a reducing and capping agent. The formation of nanoparticles was characterized by UV–vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and dynamic light scattering (DLS). The silver and gold nanoparticles exhibited absorption maxima at 425 and 551nm respectively; while for the bimetallic Ag–Au alloy appeared 520nm in between them. TEM images showed monodispersed particles in the range of 8–10nm. The crystallinity of the nanoparticles was assured by XRD analysis. DLS data gave particle size distribution. The dextran stabilized Au nanoparticles used as a colorimetric sensor for detection and estimation of pesticide present in water. The dextran stabilized Ag–Au alloy nanoparticles exhibited interesting antimicrobial activity against bacteria at micromolar concentrations.