The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
"Adhesion of Cells, Viruses and Nanoparticles" describes the adhesion of cells, viruses and nanoparticles starting from the basic principles of adhesion science, familiar to postgraduates, and leading on to recent research results. The underlying theory is that of van der Waals forces acting between cells and substrates, embodied in the molecules lying at the surfaces, together with the...
In biological adhesion systems, a wide range of cell contact geometries has been found.1–3 Where cells such as pollen or fungal spores need to be dispersed, the surfaces tend to be covered by spikes which prevent intimate extended contact between the particles, allowing the van der Waals force to be reduced to a low value. When adhesion needs to be maximised, for example where flies cling to the ceiling...
This chapter provides an overview of the different measurement methods for studying adhesion phenomena. Cells, viruses, and nanoparticles have a typical length scale ranging from tens of micrometres down to several nanometres and usually reside in an aqueous solution that significantly decreases adhesion forces. The small length and force scales as well as the liquid environment pose distinct requirements...
As particles are smaller, towards the nanometer range, or when the gaps between surfaces approach the molecular level, it becomes necessary to consider not only the macroscopic i.e. average features of the adhesion, but also the Brownian movement and statistical nature of van der Waals bonding which is fluctuating and diffusing very significantly when viewed at the scale of atomic bonds.
As we start to look at nanoparticles, viruses and cells, it becomes apparent that the one parameter model described in the previous chapters breaks down. The reason is that the van der Waals forces act over a certain distance which becomes comparable in size to the particles themselves. The approximation that work of adhesion alone is sufficient to describe adhesion then becomes unsatisfactory and...
The effect of van der Waals force can be demonstrated by compacting yeast cells under pressure to make a tablet. The cells stick together naturally once they are brought together, just like polymer, metal or ceramic particles. It becomes clear that no adhesive glue, no ‘Velcro’ interlocking, no electrostatic charge and no suction is necessary. The definition of van der Waals force can then be expressed...
Nanoparticles are ubiquitous: in the vacuum of space where they are visible through their spectral signatures,1 and also on earth where they are present in the atmosphere as aerosols, in fresh waters where they occur as humic substances causing the brown colour in bog water and as clay particles from erosion of rocks, and in the sea where they can be precipitated from silicate and calcium-based solutions...
Just as viruses are known to adhere to cells, then penetrate and kill them as described in Chapter 9, so nanoparticles (NPs) may attach to cells and cause damage. The mechanisms dominating such toxicity are not fully established but it seems clear that the molecules at the NP surface, i.e. the adhesion molecules, must be important. Moreover, the size of the particles is crucial; larger particles of...
In Part I of this book we have considered the several elements required in a description of adhesion. Now let us use these ideas to describe adhesion observations on nanoparticles, viruses and cells in different circumstances. At scales above 10 μm, where Brownian movement can be largely neglected, adhesion appears macroscopic, steady and static when viewed with the optical microscope. The...
This chapter deals with the adhesion of cells, especially the dependence on elasticity. First, we will discuss cell adhesion phenomena starting from the biological foundations. Then, we study artificial model systems to show how the elastic modulus and geometry affect cell adhesion and cause cell differentiation. Finally, at the end of the chapter we describe recent research to demonstrate that complex...
Harrison1 originally showed 100 years ago that animal cells required adhesion to a solid surface if they were to move, grow and reproduce. That observation was the basis for tissue culturing which has been universally applied over the past century for growing and studying human cells. Following that invention of cultured cells, viruses could then be grown controllably within the cells so that the...
The problem of understanding adhesion of cells, viruses and nanoparticles is defined. Although such adhesion is vital in areas such as cell culture, infection, sexual interaction, signalling, embryonic development and cancer, there are difficulties in reaching a consistent picture of cell adhesion. For example, it is known that cells stick best to clean, smooth surfaces. Contamination and roughness...
Viruses exist in a wide spread of varieties with interesting mechanisms for adhering to each other, to neighbouring particles and particularly to living cells which they target by specific means. If this adhesive targeting mechanism changes slightly, then different cells, for example human rather than bird in the case of avian influenza, may be singled out for virus attachment and new infections can...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.