While nuclear magnetic resonance (NMR) is regarded as
a reference
in fragment-based drug design, its implementation in a high-throughput
manner is limited by its lack of sensitivity resulting in long acquisition
times and high micromolar sample concentrations. Several hyperpolarization
approaches could, in principle, improve the sensitivity of NMR also
in drug research. However, photochemically induced dynamic nuclear
polarization (photo-CIDNP) is the only method that is directly applicable
in aqueous solution and agile for scalable implementation using off-the-shelf
hardware. With the use of photo-CIDNP, this work demonstrates the
detection of weak binders in the millimolar affinity range using low
micromolar concentrations down to 5 μM of ligand and 2 μM
of target, thereby exploiting the photo-CIDNP-induced polarization
twice: (i) increasing the signal-to-noise by one to two orders in
magnitude and (ii) polarization-only of the free non-bound molecule
allowing identification of binding by polarization quenching, yielding
another factor of hundred in time when compared with standard techniques.
The interaction detection was performed with single-scan NMR experiments
of a duration of 2 to 5 s. Taking advantage of the readiness of photo-CIDNP
setup implementation, an automated flow-through platform was designed
to screen samples at a screening rate of 1500 samples per day. Furthermore,
a 212 compounds photo-CIDNP fragment library is presented, opening
an avenue toward a comprehensive fragment-based screening method.