Seminar of the Division of Biomedical Physicochemistry
Microsoft Teams
Pushing the Limits of Force Detection with Avalanching Nanoparticles
Dr. Natalie Fardian-Melamed
Columbia University, New York, USA
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The seminar will be held remotely using Microsoft Teams. People in the intibs.pl domain can join the Seminarium OFB team using the code: 7aoxdkd. Other persons are asked to contact us at
Abstract:
It has recently been shown that ensembles of lanthanide-doped upconverting nanoparticles (UCNPs) exhibit changes in their emission spectra due to applied forces in the nano-Newton regime and beyond [1-2]. Classical UCNPs appear promising for in vivo, sub-cellular, mechanical force sensing due to their nano-scale dimensions, their responsiveness to tissue-penetrating near-infrared (NIR), their non-binary optical readout, and their wide force-range mechano-sensitivity. However, the lowest forces detected by classical UCNPs are only in the nano-Newton regime [1], have so far been measured only on an ensemble level (due, in large part, to low single-particle brightness) [2], and while emitting non-biocompatible visible light.
Avalanching UCNPs (ANPs) [3], possessing steeply nonlinear optical responses, are ideally suited for sensing minute changes in their environments, as small perturbations are expected to usher large changes in signal. Because ANPs absorb and emit tissue-penetrating NIR light, they are uniquely positioned for sensing within biological cells and fluids. In order to characterize and understand the response of these ANPs to local stress and hence determine their functionality as mechano-sensors, it is important to study their mechano-opto-physics on a single particle level. Utilizing a custom designed combined AFM and inverted optical microscope system, we correlate sub-nano-Newton-range applied forces and observable changes in hyperspectral optical signals for isolated optimally-designed single ANPs, demonstrating their attractiveness as physiologically-relevant ultrasensitive local force sensors.
References:
[1] McLellan CA, et al. J. Phys. Chem. Lett., 13(6), 1547 (2022)
[2] Casar JR, et al. ACS Photonics, 8(1), 3 (2020)
[3] Lee C, et al. Nature, 589(7841), 230 (2021)
