Cinzia Casiraghi

Bio: Cinzia Casiraghi is an academic researcher from University of Manchester. The author has contributed to research in topics: Graphene & Raman spectroscopy. The author has an hindex of 53, co-authored 129 publications receiving 29830 citations. Previous affiliations of Cinzia Casiraghi include Free University of Berlin & University of Cambridge.

145 Application of graphene based coating on coronary artery stents

Abstract: Coronary artery disease is the leading cause of death worldwide. Stent implantation is the mainstay approach to revascularise stenosed coronary arteries. Bare metal stents were the first stents designed, but presented a restenosis risk of approximately 20% of patients due to restenosis. Subsequently, drug eluting stents were introduced, which, however, introduced late in stent thrombosis. We propose the use of a graphene based coating onto bare metal stents in an attempt to significantly reduce stent associated complications and promote vessel healing. Graphene is a single layer of carbon atoms arranged in a honeycomb lattice. The unique properties of graphene make it an ideal material to use as an implantable device coating: It has a high surface to volume ratio; it is impermeable and atomically smooth and has been shown to exhibit bio-compatible properties. Graphene based dispersions were prepared by liquid phase exfoliation in water. Investigations to coat bare metal stents were undertaken. Dip, spin and spray coating methods were explored. Raman spectroscopy was measured to identify and characterise the coated material. Raman spectroscopy demonstrated spray coating to result in the most uniform and thin graphene based coating. In addition, human endothelial cell adherence and proliferation on the graphene based coating was studied. Hoechst 33 342 and phalloidin stains were used to image the cells under fluorescence microscopy. This revealed the adherence of human endothelial cells to be unaffected by the graphene based coating. In conclusion, spray coating created the most uniform and thin graphene based coating onto bare metal stents. Human coronary artery endothelial cell adherence occurred on the graphene coated stents. Future work is aimed at studying bio- and haemo- compatibility of graphene based coating and their performance in a porcine stent model.

The roughening kinetics of hydrogenated graphene

Abstract: The roughness is a common property of all growing surfaces – however, the way the roughness of a growing surface changes with time and space is uniquely related to the underlying growth process, i.e. to how the atoms stick to the surface during the first stage of nucleation. This concept allows getting insights on the nucleation process of a growing surface by measuring two scaling exponents, α and β, known as roughness and growth exponents, respectively. In this work, we studied hydrogenation of graphene using the roughening kinetics. The coverage of graphene will depend on how the H ions stick on the surface, giving rise to a unique roughness evolution in time and space. We measured a roughness exponent of ~0.5 (derived from a Fourier index of ~3), and a growth exponent of ~0.3. The values of the growth and roughness exponents are close to those reported for clustered carbon, suggesting a roughening mechanism by clustering, in good agreement with the theory. We also compared our coverage data with a different model, used to describe the dynamics of graphene coverage, during chemical vapour deposition. Our data are in agreement with a nucleation-dominated growth, further confirming that hydrogenation is happening by clustering.

Water-based 2D-crystal Inks: From formulation engineering to printed devices

Abstract: The electronics industry has been dominated by metals and complementary metal-oxide-semiconductor (CMOS) technology. However, constraints related to materials choice clearly appear in transparent and flexible electronics, heat management and rapid customisation — all of which present challenges to traditional fabrication methods. As a consequence of this need, the field of printable electronics has initially developed after the introduction of conductive polymers, allowing simple, versatile, and low cost techniques, such as inkjet printing, to be used for manufacturing of functional devices [1-2]. The advent of 2-Dimensional (2D) materials [3] show promise in this regard as they can be easily solution processed by using a mass scalable and low cost method, called Liquid-Phase Exfoliation [4]. 2D materials shows great promise for use in flexible electronics because their atomic thickness allows for maximum electrostatic control, optical transparency, sensitivity and mechanical flexibility [5]. In addition, different 2D crystals can be easily combined in one stack, offering unprecedented control on the performance and functionalities of the resulting heterostructure device [3].

Nanoscale insights into the structure of solution-processed graphene by x-ray scattering

Abstract: Chemical exfoliation is an attractive approach for the synthesis of graphene due to its low cost and simplicity. However, challenges still remain in the characterization of solution-processed graphene, in particular with atomic resolution. Through this work we demonstrate the x-ray pair distribution function as a novel approach to study solution-processed graphene or other 2D materials with atomic resolution, directly in solution, produced by liquid-phase and electrochemical exfoliations. The results show the disappearance of long-range atomic correlations, in both cases, confirming the production of single and few-layer graphene. In addition, a considerable ring distortion has been observed as compared to graphite, irrespective of the solvent used: the normal surface angle to the sheet of the powder sample should be less than 6°, compatible with ripples formation observed in suspended graphene. We attribute this effect to the interaction of solvent molecules with the graphene nanosheets.

The rise of graphene

Abstract: Graphene is a rapidly rising star on the horizon of materials science and condensed-matter physics. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a cornucopia of new physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when commercial products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena, some of which are unobservable in high-energy physics, can now be mimicked and tested in table-top experiments. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

The electronic properties of graphene

Abstract: This article reviews the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations. The Dirac electrons can be controlled by application of external electric and magnetic fields, or by altering sample geometry and/or topology. The Dirac electrons behave in unusual ways in tunneling, confinement, and the integer quantum Hall effect. The electronic properties of graphene stacks are discussed and vary with stacking order and number of layers. Edge (surface) states in graphene depend on the edge termination (zigzag or armchair) and affect the physical properties of nanoribbons. Different types of disorder modify the Dirac equation leading to unusual spectroscopic and transport properties. The effects of electron-electron and electron-phonon interactions in single layer and multilayer graphene are also presented.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene

Abstract: We measured the elastic properties and intrinsic breaking strength of free-standing monolayer graphene membranes by nanoindentation in an atomic force microscope. The force-displacement behavior is interpreted within a framework of nonlinear elastic stress-strain response, and yields second- and third-order elastic stiffnesses of 340 newtons per meter (N m(-1)) and -690 Nm(-1), respectively. The breaking strength is 42 N m(-1) and represents the intrinsic strength of a defect-free sheet. These quantities correspond to a Young's modulus of E = 1.0 terapascals, third-order elastic stiffness of D = -2.0 terapascals, and intrinsic strength of sigma(int) = 130 gigapascals for bulk graphite. These experiments establish graphene as the strongest material ever measured, and show that atomically perfect nanoscale materials can be mechanically tested to deformations well beyond the linear regime.