Abstract
ABSTRACT Silver-based nanoparticles and biomaterials have extensive biomedical applications owing to their unique antimicrobial properties. Thus, green and facile synthesis of such materials is highly desirable. This study reports an antibacterial hydrogel based on polyvinyl alcohol/sodium alginate network with the incorporation of silver nanoparticles (AgNPs), which is greenly synthesized by reductive metabolites obtained from the leaves of green tea. The ‘flower-shape’ AgNPs were acquired, it formed a mono-disperse system with a distinct uniform interparticle separation. The average size of AgNPs varied from 129.5 to 243.6 nm, which could be regulated by using different volumes of the green tea extract. Zeta potentials of the AgNPs were from −39.3 mV to −20.3 mV, indicating the moderate stability of the particles in water. In the next stage, the antibacterial polyvinyl alcohol/sodium alginate hydrogels were fabricated by incorporating prepared AgNPs. Scanning Electron Microscopy (SEM) images showed that the porous structure was obtained, and Energy Dispersive X-Ray (EDX) analysis confirmed that the AgNPs were uniformly dispersed in the polymer network. The hydrogels exhibited superior water absorption properties, which were characterized by a high swelling ratio (500–900%) and fast equilibrium. The hydrogels also exhibited good antimicrobial activity in assays with Gram-positive bacteria Escherichia coli and Gram-negative bacteria Staphylococcus aureus. To sum up, a process for the green preparation of antibacterial hydrogels based on AgNPs derived from tea leaves as a conveniently available cheap local agricultural product was established.
Highlights
Metal nanoparticles exhibit exciting properties such as electronic, magnetic, and optical properties with antibacterial activities, and are extensively applied in biomedical fields, including imaging and sensing, drug and gene delivery systems, and the isolation and detection of pathogens [1,2,3]
It was reported that the phy tochemicals in tea play a dual role as an active, reducing agent to reduce gold, silver, and palladium and as stabilizers to provide a stable coating on the surface of nanoparticles in a one-pot process [14]
We reported the use of tea extract as a reducing agent to synthesize natural moleculesstabilized AgNPs
Summary
Metal nanoparticles exhibit exciting properties such as electronic, magnetic, and optical properties with antibacterial activities, and are extensively applied in biomedical fields, including imaging and sensing, drug and gene delivery systems, and the isolation and detection of pathogens [1,2,3]. AgNPs could be synthesized by chemical reduction, photoreduction, laser synthesis, and other methods [8,9,10,11,12]. These methods are usually time-consuming and labor-intensive. Ecologically benign reducing agents, and safe stabilizers or dispersants are three critical factors to consider in the green synthesis of AgNPs. It was reported that the phy tochemicals in tea play a dual role as an active, reducing agent to reduce gold, silver, and palladium and as stabilizers to provide a stable coating on the surface of nanoparticles in a one-pot process [14]
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