Multivalued Logic Assay of the Disease Marker of α-Ketoglutaric Acid by a Luminescent MOF-Based Biosensor

Abstract

α-Ketoglutaric acid (α-KA) is an important endogenous metabolite in the Krebs cycle and considered a critical marker for various diseases. Several approaches for identifying α-KA have been reported. However, most of them are limited to single-signal transduction modes in one assay and working in the suspension state, which easily cause quantification errors and lead to false-positive detection results. Herein, a multivalue-responsive and semi-solid EuMOF-gel (EuMOG) logic biosensor is first designed and fabricated, which can realize the specific, rapid, and easy-to-differentiate naked-eye detection of the disease-associated marker of α-KA in serum through implementing one-to-two logic operation with three multicolor gates. The implementation of one-to-two logic operation can be rationally achieved by assembling 2,6-naphthalenedicarboxylic acid as both the energy donor and blue-colored output 1, photoactive Eu3+ ions as the red-emissive output 2, and α-KA stimuli as an input and energy blocker between the dual spectrum-resolved outputs into one unit. With the specific input of α-KA among various analytes, the binary code of the logic decoder switches from (0,1) to (1,0) with an obvious color change from red to cyan. Moreover, by integrating the output chromaticity into the logical operations, the concentration levels of α-KA could be easily evaluated with the intelligent EuMOG detector, which has three multicolor gates in parallel encoding low (0,1), normal (1,1), and danger (1,0) statuses. Such multivalued logic biosensor provides a facile strategy to improve the analysis reliability of disease-associated biomarkers.

An electrochemically deposited ordered hierarchical metal–organic framework-based dual-module sensor for decoding organic vapors

“…4a and e, significant absorbance overlap between the analytes and the ligand can be observed in UV-vis absorption spectroscopy, indicating strong competition that led to quenching. 49…”

Lanthanide upconversion and downshifting luminescence for biomolecules detection

“…In order to improve the sensing reliability of biomarkers, Li's group provided a facile technique to fabricate a semi-solid EuMOF-gel that can sense an endogenous metabolite called a-ketoglutaric acid in serum. 94 Almost at the same time, the same group provided another approach to tailor the performances of Eu-ZnMOF through structural engineering, 95 which can detect the concentration variation of urinary vanillylmandelic acid, an early pathological signature of pheochromocytoma.…”

Multicolor Fluorescent Inks Based on Lanthanide Hybrid Organogels for Anticounterfeiting and Logic Circuit Design

“…Molecular logic is an interdisciplinary research field that has attracted worldwide attention. − The most common cases of molecular logic gates include chemical input signals and optical output fluorescent signals. − The logic output can be observed by variation of the emitted fluorescence intensity, and the basis of the logic operation is established by the known Boolean arithmetic function. Clearly, multicolor-based fluorescent ink logic gates offer a new detection strategy in the field of molecular diagnostics. ,− …”