Sample handling in surface sensitive chemical and biological sensing : a practical review of basic fluidics and analyte transport

摘要

This paper gives an overview of the advantages and associated caveats of the most common sample handlingud methods in surface-sensitive chemical and biological sensing.We summarize the basic theoretical and practicalud considerations one faces when designing and assembling the fluidic part of the sensor devices. The influence ofud analyte size, the use of closed and flow-through cuvettes, the importance of flow rate, tubing length and diameter,ud bubble traps, pressure-driven pumping, cuvette dead volumes, and sample injection systems are allud discussed. Typical application areas of particular arrangements are also highlighted, such as themonitoring of cellularud adhesion, biomolecule adsorption–desorption and ligand–receptor affinity binding. Our work is a practicalud review in the sense that for every sample handling arrangement considered we present our own experimentalud data and critically reviewour experience with the given arrangement. In the experimental partwe focus on sampleud handling in optical waveguide lightmode spectroscopy (OWLS) measurements, but the present study isud equally applicable for other biosensing technologies in which an analyte in solution is captured at a surfaceud and its presence is monitored. Explicit attention is given to features that are expected to play an increasingly decisiveud role in determining the reliability of (bio)chemical sensingmeasurements, such as analyte transport to theud sensor surface; the distorting influence of dead volumes in the fluidic system; and the appropriate sample handlingud of cell suspensions (e.g. their quasi-simultaneous deposition). At the appropriate places, biological aspectsud closely related to fluidics (e.g. cellular mechanotransduction, competitive adsorption, blood flow in veins) areud also discussed, particularly with regard to their models used in biosensing.