Title
Hyperpolarized Amino Acid Derivatives as Multivalent Magnetic Resonance pH Sensor Molecules.
Abstract
pH is a tightly regulated physiological parameter that is often altered in diseased states like cancer. The development of biosensors that can be used to non-invasively image pH with hyperpolarized (HP) magnetic resonance spectroscopic imaging has therefore recently gained tremendous interest. However, most of the known HP-sensors have only individually and not comprehensively been analyzed for their biocompatibility, their pH sensitivity under physiological conditions, and the effects of chemical derivatization on their logarithmic acid dissociation constant (pK(a)). Proteinogenic amino acids are biocompatible, can be hyperpolarized and have at least two pH sensitive moieties. However, they do not exhibit a pH sensitivity in the physiologically relevant pH range. Here, we developed a systematic approach to tailor the pKa of molecules using modifications of carbon chain length and derivatization rendering these molecules interesting for pH biosensing. Notably, we identified several derivatives such as [1-C-13] serine amide and [1-C-13]-2,3-diaminopropionic acid as novel pH sensors. They bear several spin-1/2 nuclei (C-13, N-15, P-31) with high sensitivity up to 4.8 ppm/pH and we show that C-13 spins can be hyperpolarized with dissolution dynamic polarization (DNP). Our findings elucidate the molecular mechanisms of chemical shift pH sensors that might help to design tailored probes for specific pH in vivo imaging applications.
Year
DOI
Venue
2018
10.3390/s18020600
SENSORS
Keywords
Field
DocType
pH sensors,hyperpolarized,dissolution dynamic nuclear polarization,magnetic resonance spectroscopic imaging,nuclear magnetic resonance,amino acids
Derivatization,Analytical chemistry,Amide,Molecule,Acid dissociation constant,Amino acid,Combinatorial chemistry,Serine,Engineering,Biosensor,Magnetic resonance spectroscopic imaging
Journal
Volume
Issue
ISSN
18
2.0
1424-8220
Citations 
PageRank 
References 
1
0.41
0
Authors
12