<p>One-Step Synthesis of Polypyrrole-Coated Gold Nanoparticles for Use as a Photothermally Active Nano-System</p>

Abstract

Objective: This paper introduces a simple one-step and ultra-fast method for synthesis of highly photothermally active polypyrrole-coated gold nanoparticles. The synthesis process is so simple that the reaction is very fast without the need for any additives or complicated steps. Methodology: Polypyrrole-coated gold nanoparticles (AuPpy NPs) were synthesized by reacting chloroauric acid (HAuCl 4) with pyrrole (monomer) in aqueous medium at room temperature. These nanoparticles were characterized by UV-visible-NIR spectrometry, transmission electron microscopy (TEM), AC conductivity, zeta sizer and were evaluated for dark cytotoxicity and photocytotoxicity using human hepatocellular carcinoma (HepG2) cell line as a model for cancer cells. Results: The synthesized AuPpy NPs showed a peak characteristic for gold nanoparticles (530-600 nm, molar ratio dependent) and a wide absorption band along the visible-NIR region with intensity about triple or even quadruple that of polypyrrole synthesized by the conventional FeCl 3 method at the same concentration and under the same conditions. TEM imaging showed that the synthesized AuPpy NPs were composed of spherical or semi-spherical gold core(s) of about 4-10 nm coated with distinct layer(s) of polypyrrole seen either loosely or in clusters. Mean sizes of the synthesized nanoparticles range between~25 and 220 nm (molar ratio dependent). Zeta potentials of the AuPpy NPs preparations indicate their good colloidal stability. AC conductivity values of AuPpy NPs highly surpass that of Ppy prepared by the conventional FeCl 3 method. AuPpy NPs were non-toxic even at high concentrations (up to 1000 µM pyrrole monomer equivalent) under dark conditions. Unlikely, light activated the photothermal activity of AuPpy NPs in a dose-dependent manner. Conclusion: This method simply and successfully synthesized AuPpy NPs nanoparticles that represent a safe alternative photothermally active multifunctional tool instead of highly toxic and non-biodegradable gold nanorods.

(Rose Bengal)/(Eosin Yellow)-Gold-Polypyrrole Hybrids: A Design for Dual Photo-Active Nano-System with Ultra-High Loading Capacity

“…In this method, RB/EY was added to the already prepared AuPpy NPs as thoroughly described in a previous work by Fadel et al 43 Briefly, 1 mL of 10 mM chloroauric acid was rapidly added to 20 mL of 25 mM of stirred aqueous solution of pre-distilled pyrrole at room temperature (25°C), left for 2–3 min to assure reaction completion, centrifuged at 10,000 rpm for 60 min (Kontron, Italy), and then redispersed in double-distilled water to get the intended concentration. Then, RB/EY was added to the already prepared AuPpy NPs in different concentrations (100, 200 and 500 µM), sonicated for 10 minutes, left for 24 hours in a dark cool place and finally centrifuged at 10,000 rpm for one hour to get rid of excess RB and EY.…”

“…42 In a previous work, we introduced highly dispersed polypyrrole-coated gold nanoparticles as a novel photothermal agent with high tolerability, compatibility and good pharmaceutical properties. 43 In this study, rose bengal and eosin yellow, which are well-known photosensitizers, were loaded into the aforementioned nanoparticles, and the resulting loaded nanoparticles were characterized and examined for their cytotoxicity and photocytotoxicity.…”

Synthesis and factor affecting on the conductivity of polypyrrole: a short review

“…PPy can be easily prepared in solution and shows unique electrical conductivity, good stability at room temperature, and unique redox property 32,33 . PPy could be synthesized based on the oxidative polymerization of Py monomer in organic solvents (acetonitrile and propylene carbonate) and aqueous medium (water and acid solution) in the presence of iron (III) chloride (FeCl 3 ) ammonium persulfate (APS) or other oxidizing agents 34,35 . Oxidative polymerization is regarded as the oldest polymerization reaction utilized to obtain π‐conjugated polymers 7 .…”

“…Oxidative polymerization is regarded as the oldest polymerization reaction utilized to obtain π‐conjugated polymers 7 . Oxidative polymerization may be performed chemically, electrochemically, or through ultrasonic waves 35,36 . The most commonly used synthesis methods for PPy are chemical and electrochemical polymerization 37,38 .…”

PEGylated Nanographene Oxide in Combination with Near-Infrared Laser Irradiation as a Smart Nanocarrier in Colon Cancer Targeted Therapy

“…Exactly in the advanced stages of colon cancer, the patients undergo chemotherapy, which, in many cases, is also futile, as often the tumor cells develop drug resistance [ 6 , 7 ]. For this reason, oncological research is investing many efforts toward finding new and efficient therapies that can overcome the limitations of conventional treatments [ 8 , 9 , 10 ].…”