Force vs loading rate plots for Aβ42 dimer dissociation in aqueous, Cu²⁺ [20nM], and Zn²⁺ [20nM] environments.

<p>The force plots have been fit with the Friddle-De Yoreo reversible binding model [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0147488#pone.0147488.ref034" target="_blank">34</a>]. Adjusted R² values of fits are 0.979, 0.897, and 0.808 for aqueous, copper, and zinc data, respectively.</p

Mechanically induced Aβ binding and dissociation.

<p>(A) is a representative experimental force plot: the tip approaches the sample (red line) and when it touches the surface—the cantilever bends (steep linear region). The two surface-bound monomers are allowed to bind (red to blue transition at top of linear region. The cantilever retracts (blue steep linear region). As the cantilever returns to its neutral position, the force plot passes through the base line. At this point the system is in its minimum free energy state (B). The cantilever is not deflected and the system resembles a stable dimeric state (B). As the cantilever retracts, a mechanical force is applied along the reaction coordinate and the free energy of the system increases (E). The system reaches its maximum free energy just prior to rupture at x = x_β (E) at which point the cantilever is at its maximum deflection (C). At dissociation, the cantilever returns to its neutral position (D) and all free energy of the system is lost [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0147488#pone.0147488.ref040" target="_blank">40</a>].</p

Cyclodextrin-Based Pseudorotaxanes: Easily Conjugatable Scaffolds for Synthesizing Hyperpolarized Xenon-129 Magnetic Resonance Imaging Agents

Hyperpolarized (HP) xenon-129 (Xe) magnetic resonance (MR) imaging has the potential to detect biological analytes with high sensitivity and high resolution when coupled with xenon-encapsulating molecular probes. Despite the development of numerous HP Xe probes, one of the challenges that has hampered the translation of these agents from in vitro demonstration to in vivo testing is the difficulty in synthesizing the Xe-encapsulating cage molecule. In this study, we demonstrate that a pseudorotaxane, based on a γ-cyclodextrin macrocycle, is easily synthesized in one step and is detectable using HyperCEST-enhanced ¹²⁹Xe MR spectroscopy