Exogenous matrix effects

Matrix effects (ME), caused by co-eluting endogenous and exogenous matrix components, significantly affect the efficiency and reproducibility of the ionization process of target analytes. This phenomenon represents a major concern for LC-MS bioana-lytical method precision, accuracy, sensitivity, and robustness. Amongst the atmospheric pressure ionization interfaces used in LC-MS systems, ESI source is more prone to signal alteration (ion suppression or enhancement) due to matrix. Therefore, careful evaluation and correction for ME must be considered particularly with ESI-MS. 

The paper is organized in three parts. First, the effects of nanoconfinement on the structure of the sol-gel trapped biomolecule are discussed. Second, from the results on apparent reactivity of these biomaterials, the effects of the matrix on the reactivity of trapped enzyme are elucidated. Finally, the interaction of the confined biomolecules with exogenous ligands/substrates and the applications of these materials in the area of molecular biorecognition are discussed. The reaction chemistries of biologically active molecules in die nanostructured materials have been crucial in establishing the role of the matrix upon the structure and reactivity of the confined proteins. 

G.L. Meng, S.Y. Liu, and D.E. Rancourt, Synergistic effect of medium, matrix, and exogenous factors on the adhesion and growth of human pluripotent stem cells under defined, xeno-free conditions. Stem Cells Develop., 21 (11) 2036-2048, Jul. 2012. 

The immediate surroundings, the matrix, of any sensor affect mass transfer of educts and products from and to the sensor. Also, endogenous and exogenous interferents as well as ambient effects may lead to significant unspecific sensor response. These effects have successfully been tackled by BGM sensors (see, e.g., [297]). CGM sensors, which need to measure glucose continuously over days, have to tackle additional issues which complicate accurate, precise, and reproducible measurement over time. Issues will be listed and discussed in subsequent paragraphs. 

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