Graphene Oxide Quantum Dots Covalently Functionalized PVDF Membrane with Significantly-Enhanced Bactericidal and Antibiofouling Performances

Abstract

Covalent bonding of graphene oxide quantum dots (GOQDs) onto amino modified polyvinylidene fluoride (PVDF) membrane has generated a new type of nano-carbon functionalized membrane with significantly enhanced antibacterial and antibiofouling properties. A continuous filtration test using E. coli containing feedwater shows that the relative flux drop over GOQDs modified PVDF is 23%, which is significantly lower than those over pristine PVDF (86%) and GO-sheet modified PVDF (62%) after 10 h of filtration. The presence of GOQD coating layer effectively inactivates E. coli and S. aureus cells, and prevents the biofilm formation on the membrane surface, producing excellent antimicrobial activity and potentially antibiofouling capability, more superior than those of previously reported two-dimensional GO sheets and one-dimensional CNTs modified membranes. The distinctive antimicrobial and antibiofouling performances could be attributed to the unique structure and uniform dispersion of GOQDs, enabling the exposure of a larger fraction of active edges and facilitating the formation of oxidation stress. Furthermore, GOQDs modified membrane possesses satisfying long-term stability and durability due to the strong covalent interaction between PVDF and GOQDs. This study opens up a new synthetic avenue in the fabrication of efficient surface-functionalized polymer membranes for potential waste water treatment and biomolecules separation.

Biocompatibility and Toxicity of Graphene Quantum Dots for Potential Application in Photodynamic Therapy

“…The natural wettability of the surface is reflected by the CA parameter measured immediately through water droplets on the material surface. As shown in Figure 2 a-b, the contact angle for water soluble GQDs was 11°, indicating the high hydrophilicity due to the existence of hydrophilic carboxylic groups [37] . The contact angle of 16° for heavy water soluble GQDs was comparable to water soluble GQDs as well as 21.8° on mica substrates.…”

Development of a stable cation modified graphene oxide membrane for water treatment

“…Nowadays, the most common materials applied in water treatment are inorganic (ceramic) and organic polymeric membranes. In general, polymeric membranes are simpler and easier to prepare, and more flexible, but their limitations include relatively poor chemical resistance, a limited lifetime, and serious membrane fouling (Han et al 2013, Zeng et al 2016. In contrast, although ceramic membranes enjoy a distinct advantage in strength, thermal stability, solvent resistance, and longer lifetime, they are more complex and expensive to fabricate, and more brittle (Karan et al 2012, Han et al 2013.…”

Nanosized Building Blocks for Customizing Novel Antibiofilm Approaches

“…In contrast, emerging bottom-up procedures using NEs as the building blocks for surface design have been gaining increased attention in biomaterials engineering (Jo et al 2014;Horev et al 2015;Zeng et al 2016). The control of morphology (i.e., shape and size), structure (i.e., composition, porosity, density), and function (e.g., antibacterial, anticancer) is now performed at length scales from a few to hundreds of nanometers ( Fig.…”

“…NE coatings for dental applications can also benefit from advances on graphene oxide (GO), which has been shown to have antiadhesion and antibacterial properties (Zeng et al 2016). The mechanism in which GO induces antimicrobial effects are not yet fully understood, although the size of the GO sheet appears to play an important role (Perreault et al 2015).…”

“…In antimicrobial coatings, the killing effect may occur essentially by physicochemical interactions at the microbecoating interface (Perreault et al 2015;Zeng et al 2016) or by the release of antimicrobial ions/agents (Massa et al 2014;Jo et al 2014;Jia et al 2016). Therefore, relevant parameters that influence the nanoparticle decomposition/dissolution must be considered (Le Ouay and Stellacci 2015), since these processes alter the bioactive agent release.…”