Graphene‐Based Bacterial Filtration via Electrostatic Adsorption

Abstract

ditions lack clean water, fecal-oral diseases can proliferate rapidly. Diarrhea may not seem deadly to those who have access to improved sanitation, but it kills 750 000 children every year that is more than malaria, AIDS, and measles combined. [2] Waterborne pathogens are also of great concern in the hospital environment, as the water temperatures and the complex structure of hospital water systems are suitable for bacterial growth and biofilm formation. [3,4] These pathogens in connected devices (such as sinks, showers, ice machines, water baths, eyewash stations, and dental units) can lead to severe infections, especially with the rising number of multidrug-resistant bacteria. [5,6] The faucet micropore filters that are used to prevent this outcome must be replaced after a few weeks of use, making them very costly. Novel antibacterial technologies may offer practical and cost-effective prevention strategies for these concerns.Graphene materials have been reported to exhibit antibacterial activity by physically interacting with bacterial cells. [7][8][9] These flexible, singleatom-thick, nano-micrometer sized sheets feature an extremely large surface area. [10,11] Among the variety of different graphene materials, graphene oxide (GO) is frequently used due to its inexpensive preparation from graphite [12][13][14][15][16] as well as its hydrophilic functional groups, which enhance its dispersibility in polar solvents and offer multiple options for chemical post-modification. [17,18] In a previous work we demonstrated that polymer post-modification of micrometer-sized GO can be used to create polycationic microsheets. [19] These flexible GO microsheets matched the size and surface-charge density of opposite charged E. coli bacterial cells. Incubating them with gram-positive methicillinresistant Staphylococcus aureus (MRSA) and gram-negative Escherichia coli (E. coli) led to wrapping and immobilization of bacterial cells in both cases. [19] Based on multivalent electrostatic attraction, these GO derivates (GOX) also showed antibacterial activity when they were attached to a carrier material. [20,21] Although many polycationic polymers like chitosan, [22,23] polyethylene imine, [24,25] ε-polylysine, [26] polysiloxanes, [27,28] polyionenes [29,30] as well as modified GO materials with various conjugated moieties like mannose, [31] lactose, [32] quaternary ammonium compounds [33,34] and zwitterionic systems [35] have been shown to bind and inhibit bacteria, investigation Flexible graphene oxide (GO) microsheets with attached positively charged polymers, termed GOX microsheets, are efficient at bacterial adsorption, as they bind electrostatically to bacterial membranes' negative surface charge. The authors explore an antimicrobial water filter application for GOX's extremely high surface area and its previously described efficient bacterial adsorption. Cellulose-fiber carrier material is functionalized with GOX microsheets to create an adsorption-based bacteria filtration material. The morphology and charge density (7...

Bactericidal Hollow S-NiCo2O4 Nanoneedles for Air Purification

“…But in some specific application scenarios, such as hospitals, ships, etc., it is necessary to achieve rapid inactivation of bacteria in the air circulating in confined spaces. 6 To prevent this problem, thermal sterilization, 7 UV sterilization, 8 chemical sterilization, 9 high voltage field sterilization, 10−12 and other methods combined with filtration have been reported for indoor air purification in the past decades, but each of these methods has a high cost, poor biocompatibility, ecological unfriendliness, and other disadvantages that are difficult to overcome. Therefore, it is urgent to develop an efficient and practical air purification method.…”

“…With the emphasis on healthy living, there is an urgent need to develop a method that can be efficient, safe, and environmentally friendly to purify indoor air and prevent the further spread of infectious diseases. − Common physical adsorption methods such as the modification of activated carbon fiber, through its own positive charged and the negative charge on the surface of the bacterial membrane between the Coulomb force adsorption, in a low flow rate can achieve more than 99.5% of the blocking rate. But in some specific application scenarios, such as hospitals, ships, etc., it is necessary to achieve rapid inactivation of bacteria in the air circulating in confined spaces . To prevent this problem, thermal sterilization, UV sterilization, chemical sterilization, high voltage field sterilization, − and other methods combined with filtration have been reported for indoor air purification in the past decades, but each of these methods has a high cost, poor biocompatibility, ecological unfriendliness, and other disadvantages that are difficult to overcome.…”

Fe3O4@PDA@PEI Core-Shell Microspheres as a Novel Magnetic Sorbent for the Rapid and Broad-Spectrum Separation of Bacteria in Liquid Phase

“…Previous microbiology methods, including bacterial culture [ 9 ] or multiplex polymerase chain reaction (PCR) assay [ 10 , 11 ], immunology-based methods [ 12 , 13 ], have the following problems: long detection time, vulnerability to microbial contamination, limited laboratories of professional inspection institutions, and the inability to enrich and detect bacteria on-site in time [ 14 ]. Therefore, efficient enrichment of bacteria is a necessary and urgent matter, and the commonly used nanocomposite for electrostatic adsorption of bacteria are polyethersulfone nanofibrous membranes [ 15 ], flexible graphene oxide (GO) microsheets [ 16 ], and so on, but the production conditions of these materials are harsh, and the production process is complex.…”

Biomaterial-based sponge for efficient and environmentally sound removal of bacteria from water

“…Typical polycationic polymers known for their antibacterial properties are chitosan 9,10 , polyethylene imine 11 , and ε-polylysine 12 . These, along with quaternary ammonium groups, have been employed to functionalize other materials like dendrimers 13 , particles 14,15 graphene derivatives [16][17][18][19] , textiles 20 or hydrogels [21][22][23] to incorporate antibacterial properties.…”