Nano-imaging and its applications to biomedicine

Nanotechnology tools, such as Atomic Force Microscopy (AFM), are now becoming widely used in life sciences and biomedicine. AFM is a versatile technique that allows studying at the nanoscale the morphological, dynamic, and mechanical properties of biological samples, such as living cells, biomolecules, and tissues under physiological conditions. In this article, an overview of the principles of AFM will be first presented and this will be followed by discussion of some of our own recent work on the applications of AFM imaging to biomedicine

Atomic force microscopic investigation of commercial pressure sensitive adhesives for forensic analysis

Pressure sensitive adhesive (PSA), such as those used in packaging and adhesive tapes, are very often encountered in forensic investigations. In criminal activities, packaging tapes may be used for sealing packets containing drugs, explosive devices, or questioned documents, while adhesive and electrical tapes are used occasionally in kidnapping cases. In this work, the potential of using atomic force microscopy (AFM) in both imaging and force mapping (FM) modes to derive additional analytical information from PSAs is demonstrated. AFM has been used to illustrate differences in the ultrastructural and nanomechanical properties of three visually distinguishable commercial PSAs to first test the feasibility of using this technique. Subsequently, AFM was used to detect nanoscopic differences between three visually indistinguishable PSAs

Morphological changes in textile fibres exposed to environmental stresses:atomic force microscopic examination

The ability of the atomic force microscope (AFM) to investigate the nanoscopic morphological changes in the surfaces of fabrics was examined for the first time. This study focussed on two natural (cotton and wool), and a regenerated cellulose (viscose) textile fibres exposed to various environmental stresses for different lengths of times. Analyses of the AFM images allowed us to measure quantitatively the surface texture parameters of the environmentally stressed fabrics as a function of the exposure time. It was also possible to visualise at the nanoscale the finest details of the surfaces of three weathered fabrics and clearly distinguish between the detrimental effects of the imposed environmental conditions. This study confirmed that the AFM could become a very powerful tool in forensic examination of textile fibres to provide significant fibre evidence due to its capability of distinguishing between different environmental exposures or forced damages to fibres

Correlating yeast cell stress physiology to changes in the cell surface morphology:atomic force microscopic studies

Yeasts are unicellular haploid fungi that help us to bake bread and ferment alcoholic beverages, but in some cases, they can cause infections that are sometimes fatal. Over 1000 different known species of yeasts are widely distributed in nature[1]. Although the majority of these (e.g., Saccharomyces cerevisiae) live in the general environment, a few species (e.g., Candida) are associated with humans and sometimes become pathogenic[1]. This occurs when our immune system weakens and Candida yeasts start to grow in an uncontrolled way, thereby causing candidiasis and nosocomial infections that result in high patient morbidity and mortality rates[2]

Catholic Education and the Study of Science: The Mysticism of Scientific Pursuit

In the past forty years, science has been gradually relegated to technology and utilitarian knowledge. To avoid forgetting what science truly is, it is paramount to train students to discern the difference between scientific knowledge and technological progress. Catholic education possesses the necessary tools to achieve such a goal and to give back, to science, its rightful place in human knowledge as a mystical instrument that can demonstrate the logic in the existence of a Creator beyond creation and enable humanity to climb the mountain of truth. The starting point of this ascent is to use scientific approaches to unravel the laws that govern the natural world. At the top of the mountain, the climber will contemplate the hidden mysteries of the Creator and His creation. In this paper, the development of science, from a united body of knowledge to a compartmentalized ensemble of different disciplines, will be presented. The difference between science as liberal knowledge and technology as utilitarian knowledge will also be discussed, and the fundamental role that Catholic education has to play in the restoration of scientific knowledge, as a liberal endeavour of the human mind, will be considered. The necessity of using the dialogue between faith and reason as a tool to train students in understanding the essence of scientific pursuit will be presented

Can there be a Catholic approach to the teaching of physics to students in Catholic universities? Some ideas for teachers and students to consider

We currently live in a high-tech society where portable supercomputers, artificial intelligence, genetic enhancement, etc., are becoming part of our daily life. It can be argued that this steady flow of complex technology is vigorously pushing aside religion and faith in God. Nowadays if a student decides to study physics he/she cannot possibly think of, nor have an interest in philosophy, let alone theology. This limited attitude towards physics is stripping it of its real meaning and purpose. This paper argues that physics is a study that God has put in the hands of humanity to be used in conjunction with philosophy and theology, in order not only to be able to ask big questions about nature and the universe, but also to actively contribute to finding some answers to them. Ideas about a scientific-philosophical-theological approach to teaching physics at the undergraduate level within a Catholic institution are presented and discussed

Influence of cell surface and nanomechanical properties on the flocculation ability of industrial <i>Saccharomyces cerevisiae</i> strains

In the past few years, atomic force microscopy (AFM) has provided novel information on the ultrastructural and nanomechanical properties of yeast cell walls that play a major role in determining the flocculation characteristics of the yeasts. In this study, we used AFM to visualize at the nanoscale the cell surface topography and to determine cell wall nanomechanical properties (e.g. elasticity) of different strains of S. cerevisiae employed for brewing, winemaking and fuel alcohol production. Cell surface topography was found to correlate with the flocculation behaviour of these strains during their late stationary phase, with the cell surface of flocculent cells being rougher than that of weakly flocculent cells. The elastic modulus of the yeast cell walls showed that weakly flocculent strains had a more rigid cell wall than highly flocculent strains. This difference in elasticity seemed to have an effect on the adhesive properties of the yeast cell walls, with weakly flocculent yeasts displaying higher adhesion energy than the highly flocculent strains. These findings seem to indicate that yeast cell surface nanomechanical properties play an important role in governing flocculation

Discrimination of bladder cancer cells from normal urothelial cells with high specificity and sensitivity:combined application of atomic force microscopy and modulated Raman spectroscopy

Atomic force microscopy (AFM) and modulated Raman spectroscopy (MRS) were used to discriminate between living normal human urothelial cells (SV-HUC-1) and bladder tumour cells (MGH-U1) with high specificity and sensitivity. MGH-U1 cells were 1.5-fold smaller, 1.7-fold thicker and 1.4-fold rougher than normal SV-HUC-1 cells. The adhesion energy was 2.6-fold higher in the MGH-U1 cells compared to normal SV-HUC-1 cells, which possibly indicates that bladder tumour cells are more deformable than normal cells. The elastic modulus of MGH-U1 cells was 12-fold lower than SV-HUC-1 cells, suggesting a higher elasticity of the bladder cancer cell membranes. The biochemical fingerprints of cancer cells displayed a higher DNA and lipid content, probably due to an increase in the nuclear to cytoplasm ratio. Normal cells were characterized by higher protein contents. AFM studies revealed a decrease in the lateral dimensions and an increase in thickness of cancer cells compared to normal cells; these studies authenticate the observations from MRS. Nanostructural, nanomechanical and biochemical profiles of bladder cells provide qualitative and quantitative markers to differentiate between normal and cancerous cells at the single cellular level. AFM and MRS allow discrimination between adhesion energy, elasticity and Raman spectra of SV-HUC-1 and MGH-U1 cells with high specificity (83, 98 and 95%) and sensitivity (97, 93 and 98%). Such single-cell-level studies could have a pivotal impact on the development of AFM–Raman combined methodologies for cancer profiling and screening with translational significance

Laboratory markers included in the Corona Score can identify false negative results on COVID-19 RT-PCR in the emergency room

After December 2019 outbreak in China, the novel Coronavirus infection (COVID-19) has very quickly overflowed worldwide. Infection causes a clinical syndrome encompassing a wide range of clinical features, from asymptomatic or oligosymptomatic course to acute respiratory distress and death. In a very recent work we preliminarily observed that several laboratory tests have been shown as characteristically altered in COVID-19. We aimed to use the Corona score, a validated point-based algorithm to predict the likelihood of COVID-19 infection in patients presenting at the Emergency rooms. This approach combines chest images-relative score and several laboratory parameters to classify emergency room patients. Corona score accuracy was satisfactory, increasing the detection of positive patients’ rate