Östen Jansson

Use of a novel micro-fluidic device to create arrays for multiplex analysis of large and small molecular weight compounds by surface plasmon resonance.

There is an increasing demand to develop biosensor monitoring devices capable of biomarker profiling for predicting animal adulteration and detecting multiple chemical contaminants or toxins in food produce. Surface plasmon resonance (SPR) biosensors are label free detection systems that monitor the binding of specific biomolecular recognition elements with binding partners. Essential to this technology are the production of biochips where a selected binding partner, antibody, biomarker protein or low molecular weight contaminant, is immobilised. A micro-fluidic immobilisation device allowing the covalent attachment of up to 16 binding partners in a linear array on a single surface has been developed for compatibility with a prototype multiplex SPR analyser. The immobilisation unit and multiplex SPR analyser were respectively evaluated in their ability to be fit-for-purpose for binding partner attachment and detection of high and low molecular weight molecules. The multiplexing capability of the dual technology was assessed using phycotoxin concentration analysis as a model system. The parent compounds of four toxin groups were immobilised within a single chip format and calibration curves were achieved. The chip design and SPR technology allowed the compartmentalisation of the binding interactions for each toxin group offering the added benefit of being able to distinguish between toxin families and perform concentration analysis. This model is particularly contemporary with the current drive to replace biological methods for phycotoxin screening.

Interfacing biomolecular interaction analysis with mass spectrometry and the use of Bioreactive mass spectrometer probe tips in protein characterization

Publisher Summary Biomolecular interaction analysis (BIA) and matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF) are capable of the accurate characterization of biomolecules with extreme speed and sensitivity. Although the two analytical approaches operate on mutually exclusive detection principles (either surface plasmon resonance detection of a refractive index change or the physical determination the molecular mass of a gas-phase ion), they can share a common denominator—the use of affinity interactions in selecting the analyte. Interfacing of the two, thereby creates a unique approach for the investigation of the kinetic parameters of biomolecular interaction (using BIA), and the unambiguous confirmation of the presence of targeted affinity ligands by direct mass analysis. In more recent times, new mass spectrometric approaches for the rapid, sensitive, and accurate characterization of proteins are in development. This chapter discusses some of the findings on the interfacing of biomolecular interaction analysis with mass spectrometry, and the use of enzymatically active—or bioreactive—mass spectrometer probe tips in the characterization of analytes. The use of bioreactive mass spectrometer probe tips to serially digest myoglobin is discussed in the chapter. The object of the serial digestion is to simultaneously view the relative stability of molecule fragments of myoglobin (generated during an initial, limited digestion of the myoglobin under denaturing conditions using pepsin-active tips at low pH), by exposing the fragment set to extensive digestion (using trypsin tips) under renaturing conditions.