Influence of the discharge time of solution plasma process on the formation of gold nanoparticles in alginate matrix

• Colloidal AuNPs-alginate suspensions were synthesized by applying the plasma into alginate aqueous solution containing gold(III) chloride trihydrate precursor.
• The SPP discharge time has a strong effect on the shape and size of the obtained AuNPs.
• A size reduction of the AuNPs is observed when the discharged time is increased.

Gold nanoparticles (AuNPs) stabilized in alginate matrix were synthesized by applying the plasma into alginate aqueous solution containing gold(III) chloride trihydrate precursor. Effect of the solution plasma process (SPP) discharge time on the physical properties, including shape and size, and the optical absorption properties of the synthesized AuNPs were investigated by varying the discharge times to be 0, 5, 10, 20 and 30 min. Results reveal that the increase in the discharge time leads to a size reduction of the AuNPs. Also, the particles tend to be more spherical. Appearance of the obtained AuNPs-alginate suspensions along with the change in their UV–vis absorption spectra intensity after samples were left standing for several time intervals suggest that alginate solution itself can act both as a stabilizer and a reducing agent for the AuNPs formation while the application of plasma helps to improve the controllability of shape and size of the synthesized particles. Furthermore, the method is simple, reproducible, and does not need any manipulative skill. Since the reducing agent is not required, the method is suitable for utilizing in biomedical application.