Oligolayer-coated nanoparticles: impact of surface topography at the nanobio interface.

Layer-by-layer coating of nanoparticles with a layer number in the single-digit range has gained increasing attention in the field of nanomedicinal research. However, the impact of using various polyelectrolytes on oligolayer formation and, more importantly, their influence on the interaction with the biological system has not often been considered in the past. Hence, we investigated the polyelectrolyte deposition profiles and resulting surface topographies of up to three polyelectrolyte layers on a flat gold sensor surface using three different polycations, namely, poly(ethylene imine) (PEI), poly(allylamine hydrochloride) (PAH), and poly(diallylammonium chloride) (PD), each in combination with poly(styrenesulfonate) (PSS).

Label-free monitoring of cell-based assays: combining impedance analysis with SPR for multiparametric cell profiling.

Label-free approaches to monitor cell-based assays provide an unprecedented, time-resolved and non-invasive view on the response of mammalian cells to chemical, biological or physical stimuli. The most widespread techniques are impedance analysis and optical sensing using evanescent waves like SPR. This study describes the combination of both in one experimental setup so that a given cell population can be monitored simultaneously for electrical and optical changes.

Real-time label-free monitoring of the cellular response to osmotic stress using conventional and long-range surface plasmons.

Cell volume and its regulation are key factors for cellular integrity and also serve as indicators of various cell pathologies. SPR sensors represent an efficient tool for real-time and label-free observations of changes in cell volume and shape. Here, we extend this concept by employing the use of long-range surface plasmons (LRSP).

Studying cell-surface interactions in vitro: a survey of experimental approaches and techniques.

A better understanding of the interactions of animal (or human) cells with in vitro surfaces is the key to the successful development, improvement and optimization of biomaterials for biomedical or biotechnological purposes. State-of-the-art experimental approaches and techniques are a prerequisite for further and deeper insights into the mechanisms and processes involved in cell-surface adhesion. This chapter provides a brief but not complete survey of optical, mechanical, electrochemical and acoustic devices that are currently used to study the structural and functional properties of the cell-surface junction.

Label-free and time-resolved measurements of cell volume changes by surface plasmon resonance (SPR) spectroscopy.

Cell volume and its regulation is one of the key players for cellular integrity and a strong indicator for several cell pathologies. But time-resolved volume measurements of adherently grown mammalian cells using established methods, such as extracellular impedance analysis or light microscopy, are complex and time-consuming. In this study, we demonstrate that surface plasmon resonance spectroscopy (SPR) is a powerful transducer device capable of reporting volume changes of cells that are directly grown on the SPR sensor surface.