Ariel Stiber
Ph.D. Student in Materials Science and Engineering, admitted Autumn 2020
All Publications
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Upconverting microgauges reveal intraluminal force dynamics in vivo.
Nature
2025; 637 (8044): 76-83
Abstract
The forces generated by action potentials in muscle cells shuttle blood, food and waste products throughout the luminal structures of the body. Although non-invasive electrophysiological techniques exist1-3, most mechanosensors cannot access luminal structures non-invasively4-6. Here we introduce non-toxic ingestible mechanosensors to enable the quantitative study of luminal forces and apply them to study feeding in living Caenorhabditis elegans roundworms. These optical 'microgauges' comprise upconverting NaY0.8Yb0.18Er0.02F4@NaYF4 nanoparticles embedded in polystyrene microspheres. Combining optical microscopy and atomic force microscopy to study microgauges in vitro, we show that force evokes a linear and hysteresis-free change in the ratio of emitted red to green light. With fluorescence imaging and non-invasive electrophysiology, we show that adult C. elegans generate bite forces during feeding on the order of 10 µN and that the temporal pattern of force generation is aligned with muscle activity in the feeding organ. Moreover, the bite force we measure corresponds to Hertzian contact stresses in the pressure range used to lyse the bacterial food of the worm7,8. Microgauges have the potential to enable quantitative studies that investigate how neuromuscular stresses are affected by ageing, genetic mutations and drug treatments in this organ and other luminal organs.
View details for DOI 10.1038/s41586-024-08331-x
View details for PubMedID 39743609
View details for PubMedCentralID 3372093
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Very-large-scale integrated high quality factor nanoantenna pixels.
Nature nanotechnology
2024
Abstract
Metasurfaces precisely control the amplitude, polarization and phase of light, with applications spanning imaging, sensing, modulation and computing. Three crucial performance metrics of metasurfaces and their constituent resonators are the quality factor (Q factor), mode volume (Vm) and ability to control far-field radiation. Often, resonators face a trade-off between these parameters: a reduction in Vm leads to an equivalent reduction in Q, albeit with more control over radiation. Here we demonstrate that this perceived compromise is not inevitable: high quality factor, subwavelength Vm and controlled dipole-like radiation can be achieved simultaneously. We design high quality factor, very-large-scale-integrated silicon nanoantenna pixels (VINPix) that combine guided mode resonance waveguides with photonic crystal cavities. With optimized nanoantennas, we achieve Q factors exceeding 1,500 with Vm less than 0.1 ( λ / n air ) 3 . Each nanoantenna is individually addressable by free-space light and exhibits dipole-like scattering to the far-field. Resonator densities exceeding a million nanoantennas per cm2 can be achieved. As a proof-of-concept application, we show spectrometer-free, spatially localized, refractive-index sensing, and fabrication of an 8 mm × 8 mm VINPix array. Our platform provides a foundation for compact, densely multiplexed devices such as spatial light modulators, computational spectrometers and in situ environmental sensors.
View details for DOI 10.1038/s41565-024-01697-z
View details for PubMedID 38961248
View details for PubMedCentralID 10971570