Lanthanide Complex Indicators for Neutral Sugars & Cancer Biomarkers

Abstract: We have developed lanthanide-based water-soluble salophene complexes that are useful in three important ways: (i) Detection of neutral carbohydrates while at physiologically-relevant pH; (ii) Selective detection of sialic-acid rich gangliosides, known cancer biomarkers; and (iii) Selective detection of lysophosphatidic acid (LPA), a potential early stage ovarian cancer biomarker, even in the presence of other phospholipids and related biomolecules. All three detection modes utilize well-established and widespread fluorescence detection to quantify results. We have overcome the long-standing problem of competitive binding by bulk water, which has until now necessitated a highly elevated, far-from-physiological pH environment for a useful extent of coordination and signal transduction to occur. We also avoid the impractically-long analytical chemistry sequence previously required to assay for LPA with a rapid, easy-to-use protocol that could easily be placed in an ordinary clinical diagnostic laboratory.