Graphene and Graphene oxide (GO) are capable of inducing stem cells differentiation into bone tissue with variable efficacy depending on reductive state of the material. Thus, modulation of osteogenic process and of bone mineral density distribution is theoretically possible by controlling the GO oxidative state. In this study, we laser-printed GO surfaces in order to obtain both a local photo-thermal GO reduction and the formation of nano-wrinkles along precise geometric pattern. Initially, after cells adhered on the surface, stem cells migrated and accumulated on the reduced and wrinkled surface. When the local density of the stem cells on the reduced stripes was high, cells started to proliferate and occupy the oxidized/flat area. The designed surfaces morphology guided stem cell orientation and the reduction accelerated differentiation. Furthermore the reduced sharp nano-wrinkles were able to enhance the GO antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA), common cause of prosthetic joints infections. This strategy can offer a revolution in present and future trends of scaffolds design for regenerative medicine.
Standing out as the new wonder bidimensional material, graphene oxide (GO) has aroused an exceptional interest in biomedical research by holding promise for being the antibacterial of future. First, GO possesses a specific interaction with microorganisms combined with a mild toxicity for human cells. Additionally, its antibacterial action seems to be directed to multiple targets in pathogens, causing both membranes mechanical injury and oxidative stress. Lastly, compared to other carbon materials, GO has easy and low-cost processing and is environmentfriendly.
This remarkable specificity and multi-targeting antibacterial activity come at a time when antibiotic resistance represents the major health challenge. Unfortunately, a comprehensive framework to understand how to effectively utilize this material against microorganisms is still lacking. In the last decade, several groups tried to define the mechanisms of interaction between GO flakes and pathogens but conflicting results have been reported. This review is focused on all the contradictions of GO antimicrobial properties in solution. Flake size, incubation protocol,
time of exposure and species considered are examples of factors influencing results. These parameters will be summarized and analyzed with the aim of defining the causes of contradictions, to allow fast GO clinical application.
The image shows the cutting of bacteria by graphene oxide flakes.
Some Web release
The super bugs are the plague of modern era. Super bugs are antibiotic resistant bacteria that will cause the death of thousands of people in the future. We need novel tools to sterilize surfaces and medical equipment; we also need novel approaches to defeat bacteria.
Within a collaboration with the University Cattolica, we recently reported in Scientific Reports on a novel “cloak” against super bugs. The cloak is a laser printed surface that includes graphene oxide. The cloak is able to kill the bacteria because the surface mimics the carapace of the Cancer Pagurus (picture above), which is known to repel dangerous organisms, and also uses graphene as a blade that cuts the bacteria (and also wrap and poison them), as in the following picture
The cloak is a novel very effective solution to sterilize surfaces, and our research sheds light on the effect of graphene against bacteria. We report 90% bacteria killing action.