Antibacterial properties of starch-reduced graphene oxide–polyiodide nanocomposite

• Published in: Food chemistry 2021-04, Vol.342, p.128385, Article 128385
• Main Authors: Narayanan, Kannan Badri, Park, Gyu Tae, Han, Sung Soo
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Antibacterial; Escherichia coli - drug effects; Food packaging; Food Packaging - methods; Graphite - chemistry; Iodides - chemistry; Microbial Sensitivity Tests; Nanocomposite; Nanocomposites - chemistry; Nanocomposites - toxicity; Polyiodide; Reduced graphene oxide; Soluble starch; Staphylococcus aureus - drug effects; Starch - chemistry
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2020.128385

•Starch-reduced graphene oxide (SRGO) was hydrothermally synthesized using soluble starch.•SRGO functionalized with amylose accommodates polyiodide to form SRGO–polyiodide nanocomposites (NCs)•SRGO–PI NC has strong antibacterial activity against Escherichia coli and Staphylococcus aureus.•Iodine-doped graphene NCs can be used for the sustained release of iodine/polyiodide.•Starch-based antibacterial nanomaterials incorporated with dopants can be used in food packaging. Graphene-based nanocomposites with superior antibacterial activity are highly sought after by the food packaging industries. Here, we report for the first time a method that utilizes soluble starch biopolymer as a functionalizing and reducing agent for the preparation of starch-reduced graphene oxide (SRGO), whereby polyiodide binds to the helical structures of amylose units of the starch (chromophore) to form a SRGO–polyiodide nanocomposite (SRGO–PI NC). UV–visible spectroscopy, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and energy-dispersive spectroscopy confirmed the presence of polyiodide in SRGO. SRGO–PI NC exhibited good antibacterial activities against pathogenic Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) microbes with minimum inhibitory concentrations (MICs) and minimum bactericidal concentration (MBC) values (as determined by a broth-dilution method) of 2.5 and 5 mg/ml, respectively, for both E. coli and S. aureus. PrestoBlue viability assays showed half-maximal inhibitory concentration (IC50) values of 0.45 and 0.41 mg/ml for E. coli and S. aureus, respectively. Time-kill kinetic and live/dead bacterial viability assays revealed the antimicrobial activities of SRGO-PI NC against both E. coli and S. aureus. The study provides new insights regarding the utilization of graphene–polyiodide NCs as high-efficacy antibacterial starch-based nanomaterials for food packaging applications.