Graphene and its derivatives have been widely employed in the manufacturing of novel composite nanomaterials which find applications across the fields of physics, chemistry, engineering and medicine. ...There are many techniques and strategies employed for the production, functionalization, and assembly of graphene with other organic and inorganic components. These are characterized by advantages and disadvantages related to the nature of the specific components involved. Among many, biomolecules and biopolymers have been extensively studied and employed during the last decade as building blocks, leading to the realization of graphene-based biomaterials owning unique properties and functionalities. In particular, biomolecules like nucleic acids, proteins and enzymes, as well as viruses, are of particular interest due to their natural ability to self-assemble
non-covalent interactions forming extremely complex and dynamic functional structures. The capability of proteins and nucleic acids to bind specific targets with very high selectivity or the ability of enzymes to catalyse specific reactions, make these biomolecules the perfect candidates to be combined with graphenes, and in particular graphene oxide, to create novel 3D nanostructured functional biomaterials. Furthermore, besides the ease of interaction between graphene oxide and biomolecules, the latter can be produced in bulk, favouring the scalability of the resulting nanostructured composite materials. Moreover, due to the presence of biological components, graphene oxide-based biomaterials are more environmentally friendly and can be manufactured more sustainably compared to other graphene-based materials assembled with synthetic and inorganic components. This review aims to provide an overview of the state of the art of 3D graphene-based materials assembled using graphene oxide and biomolecules, for the fabrication of novel functional and scalable materials and devices.
Nanotechnology involves developing, characterising, and applying structures ranging in size from 1 to 100 nm. As a key advanced technology, it has contributed to a substantial impact across ...engineering, medicine, agriculture and food. With regards to their application in food, nanomaterials posses the ability to lead the quantitative and qualitative development of high-quality, healthier, and safer foods by outperforming traditional food processing technologies for increasing shelf life and preventing contaminations. Although rapid progress has been made in nanotechnology in food products, the toxicity of nanoparticles and nanomaterials is not very well known. As a result, nanomaterials are potentially toxic, therefore, considering the constantly increasing employment in food science, they need to be further characterised, and their use must be better regulated. We may face a crisis of nanotoxicity if the molecular mechanisms by which nanoparticles and nanomaterials interact with food and within living organisms is not fully understood. Food safety can be guaranteed only if we are thoroughly aware of nanomaterial properties and potential toxicity. Therefore, it is urgently necessary to have in the food sector a regulatory system capable of managing nanofood risks and nanotechnology, considering the health effects of food processing techniques based on nanotechnology. This present review discusses the impact and role nanotechnology play in food science. The specific application of Nanomaterials in food science, their advantages and disadvantages, the potential risk for human health and the analysis to detect nanocomponents are also highlighted.
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•Nanotechnology can be used in food and feed processing at any level.•Nanocomposite materials have been used in active packaging to prevent the passage of oxygen, carbon dioxide, and moisture into the food.•Nanomaterials must be used with caution because they have the potential to cause toxic effects.•Nanomaterials can travel deeper into the nucleus of cells and damaging the DNA.•Analytical methods are required to reliably detect and characterize nanoparticles.
M13 bacteriophage is a well-established versatile nano-building block, which can be employed to produce novel self-assembled functional materials and devices. Sufficient production and scalability of ...the M13, often require a large quantity of the virus and thus, improved propagation methods characterised by high capacity and degree of purity are essential. Currently, the 'gold-standard' is represented by infecting Escherichia coli cultures, followed by precipitation with polyethylene glycol (PEG). However, this is considerably flawed by the accumulation of contaminant PEG inside the freshly produced stocks, potentially hampering the reactivity of the individual M13 filaments. Our study demonstrates the effectiveness of implementing an isoelectric precipitation procedure to reduce the residual PEG along with FT-IR spectroscopy as a rapid, convenient and effective analytic validation method to detect the presence of this contaminant in freshly prepared M13 stocks.
The COVID-19 pandemic forced the education sector to transform significantly in order to support students across the world. Technology played a crucial role in enhancing and adapting traditional ...learning to digital resources and networks, which are now an essential component of education. However, there is concern about the quality of teaching and its effectiveness in remote teaching due to the lack of real-life feel of more traditional face-to-face education. Our study analysed two separate groups of students enrolled in the same course but provided with either face-to-face or remote teaching. The results show that there is no statistically significant difference in students’ performance or gain, even for laboratory work and resulting reports. However, there was a statistically significant difference in Turnitin scores between these groups, with the remote students having higher levels of plagiarism compared to the traditional face-to-face students. These results support the theory that remote teaching can be a valid alternative, if not a substitute, to face-to-face teaching in the future. The study’s findings are expected to help instructors who are thinking about providing programs through blended learning in the post-pandemic era.
The self-assembly of graphene oxide (GO) and M13 bacteriophage results in the formation of micro-porous structures, known as GraPhage13 aerogels (GPA). Given the limited applications of aerogels in ...industry due to their nanomechanical properties, along with the previously observed temperature-dependent characteristics in graphene-based nanocomposites, a thorough exploration of the thermosensitive nanomechanical properties of GPA is essential. Herein, a comprehensive characterisation of the morphology, composition, and spectroscopic analysis of the GPA for a range of temperatures has been conducted and correlated with its nanomechanical properties. Elevated temperatures have been found to lead to gradual removal of oxygen-containing functional groups (OCFGs) from GPA, resulting in increased structural defects and reduced stiffness. Notably, unique nanomechanical behaviours of GPA have been further identified, where the thermal expansion of sp3 bonds exceeds that of a crystalline sp3 structure, while the thermal contraction of sp2 bonds in GPA is found to be between graphite and GO. This underscores the impact of GO functionalisation on the thermal expansion behaviour of GPA. The obtained insights enhance the overall comprehension of the temperature annealing impact on GPA and highlight the tunability of its nanomechanical properties, showcasing a broad potential of this novel nanocomposite across a diverse range of applications.
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To truly understand the mechanisms behind the supramolecular self-assembly of nanocomponents, the characterisation of their surface properties is crucial. M13 emerged as a practical nanocomponent for ...bio-nanoassemblies of functional materials and devices, and its popularity is increasing as time goes by. The investigation performed in this study provides important information about the surface charge and the surface area of M13 determined through the comparison of structural data and the measurement of
ζ
-potential at pH ranging between 2 and 11. The developed methodologies along with the experimental findings can be subsequently exploited as a novel and convenient prediction tool of the total charge of modified versions of M13. This, in turn, will facilitate the design of the self-assembly strategies which would combine the virus building block with other micro and nano components
via
intermolecular interactions.
Characterisation of the external surface of bacteriophage M13 using PVIII protein structural data and measuring
ζ
-potential of the entire virus.
Abstract
Honey has been valued as a powerful antimicrobial since ancient times. However, the understanding of the underlying antibacterial mechanism is incomplete. The complexity and variability of ...honey composition represent a challenge to this scope. In this study, a simple model system was used to investigate the antibacterial effect of, and possible synergies between, the three main stressors present in honey: sugars, gluconic acid, and hydrogen peroxide (H
2
O
2
), which result from the enzymatic conversion of glucose on honey dilution. Our results demonstrated that the synergy of H
2
O
2
and gluconic acid is essential for the antibacterial activity of honey. This synergy caused membrane depolarization, destruction of the cell wall, and eventually growth inhibition of
E. coli
K-12. The presence of H
2
O
2
stimulated the generation of other long-lived ROS in a dose-dependent manner. Sugars caused osmosis-related morphological changes, however, decreased the toxicity of the H
2
O
2
/gluconic acid. The susceptibility of catalase and general stress response sigma factor mutants confirmed the synergy of the three stressors, which is enhanced at higher H
2
O
2
concentrations. By monitoring cellular phenotypic changes caused by model honey, we explained how this can be bactericidal even though the antimicrobial compounds which it contains are at non-inhibitory concentrations.
The MCM motor of the replicative helicase is loaded onto origin DNA as an inactive double hexamer before replication initiation. Recruitment of activators GINS and Cdc45 upon S-phase transition ...promotes the assembly of two active CMG helicases. Although work with yeast established the mechanism for origin activation, how CMG is formed in higher eukaryotes is poorly understood. Metazoan Downstream neighbor of Son (DONSON) has recently been shown to deliver GINS to MCM during CMG assembly. What impact this has on the MCM double hexamer is unknown. Here, we used cryoelectron microscopy (cryo-EM) on proteins isolated from replicating Xenopus egg extracts to identify a double CMG complex bridged by a DONSON dimer. We find that tethering elements mediating complex formation are essential for replication. DONSON reconfigures the MCM motors in the double CMG, and primordial dwarfism patients’ mutations disrupting DONSON dimerization affect GINS and MCM engagement in human cells and DNA synthesis in Xenopus egg extracts.
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•Purified complex from replicating chromatin frog egg extracts is cryo-EM tractable•Structure of a double CMG bound by a DONSON dimer•MCM double hexamer misaligned and ready to replicate bidirectionally•Patients’ mutations impairing DONSON dimerization affect DNA replication
Cvetkovic, Passaretti, et al. determine the cryo-EM structure of a double CMG bound by dimeric DONSON, explaining how the CMG helicase is assembled symmetrically in metazoans. MCM rings become misaligned and poised to cross paths supporting replication origin activation. Disrupting DONSON dimer affects DNA replication, explaining etiology of primordial dwarfism.
Graphene, since its successful exfoliation and characterisation has been continuously drawing extensive research interests due to its potential for a broad range of applications ranging from energy, ...microelectronics, through polymer fillers and sensors to environmental and biomedical devices. Exploitation of its unique chemical and physical properties for the manufacturing of functional materials, requires careful structural control and scaling-up into three-dimensional morphologies. Here, a facile method is established to create and control the bottom-up self-assembly of graphene oxide nano-sheets via unprecedented integration with a highly versatile bio-ingredient, the filamentous bacteriophage M13, into hierarchical, three-dimensional, porous sponges of GraPhage13. This study explores the interplay of the GraPhage13 structure formation and studies the mechanisms that give rise to the controllable self-assembly. The straightforward fabrication of robust hierarchical micro-nano-architectures further lays a platform for applications in energy storage and conversion, catalysis and sensing.
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