Parivash Moradifar
Physical Science Research Scientist
Materials Science and Engineering
All Publications
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Mechanosensitive Polymer Matrices of Biologically-Relevant Compliance Based on Upconverting Nanoparticles.
Advanced materials (Deerfield Beach, Fla.)
2026: e22706
Abstract
Upconverting nanoparticles (UCNPs) are promising optical biomechanical force sensors due to their near-infrared excitation, low toxicity, photostability, and linear colorimetric sensitivity to micronewtons of force. Recently, a composite force sensor based on UCNPs embedded in a polystyrene microbead enabled the first real-time measurement of feeding forces in living nematodes. However, the comparatively large stiffness of polystyrene only makes it relevant to biomedical applications in a small subset of biological tissue. To facilitate deployment of UCNPs into biological tissues with a range of mechanical properties, we expand upon polymer-UCNP composite systems by embedding UCNPs in three polymer matrices with varying stiffnesses (epoxy resin, polydimethylsiloxane, and alginate hydrogels). Furthermore, to enhance these composites' mechanosensitivity, we methodically investigate using two different core-shell architectures of SrLuF-based UCNPs doped with ytterbium, erbium, and varying manganese concentrations. We calibrate polymer-UCNP composite optical force sensitivity with colocalized atomic force and confocal microscopy. Using the red to green emission ratio (Δ% IRed:IGreen) as the force read-out, we determine that SrLuF:Yb0.28Er0.025Mn0.013 @ SrYF dispersed in epoxy resin exhibits the greatest emission color change (12 Δ%IRed:IGreen per microNewton). Finally, we map forces in the epoxy-UCNP composite on the macroscale between the joint of a chicken wing bone using a commercially available wide-field microscope, thereby demonstrating its ability to optically measure pressures in situ. This work establishes the utility and modularity of the UCNP-polymer composite system for force-sensing in geometrically and mechanically diverse biological systems.
View details for DOI 10.1002/adma.202522706
View details for PubMedID 42007868
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High-throughput antibody screening with high-quality factor nanophotonics and bioprinting.
ArXiv
2024
Abstract
Empirical investigation of the quintillion-scale, functionally diverse antibody repertoires that can be generated synthetically or naturally is critical for identifying potential biotherapeutic leads, yet remains burdensome. We present high-throughput nanophotonics- and bioprinter-enabled screening (HT-NaBS), a multiplexed assay for large-scale, sample-efficient, and rapid characterization of antibody libraries. Our platform is built upon independently addressable pixelated nanoantennas exhibiting wavelength-scale mode volumes, high-quality factors (high-Q) exceeding 5000, and pattern densities exceeding one million sensors per square centimeter. Our custom-built acoustic bioprinter enables individual sensor functionalization via the deposition of picoliter droplets from a library of capture antigens at rates up to 25,000 droplets per second. We detect subtle differentiation in the target binding signature through spatially-resolved spectral imaging of hundreds of resonators simultaneously, elucidating antigen-antibody binding kinetic rates, affinity constant, and specificity. We demonstrate HT-NaBS on a panel of antibodies targeting SARS-CoV-2, Influenza A, and Influenza B antigens, with a sub-picomolar limit of detection within 30 minutes. Furthermore, through epitope binning analysis, we demonstrate the competence and diversity of a library of native antibodies targeting functional epitopes on a priority pathogen (H5N1 bird flu) and on glycosylated therapeutic Cetuximab antibodies against epidermal growth factor receptor. With a roadmap to image tens of thousands of sensors simultaneously, this high-throughput, resource-efficient, and label-free platform can rapidly screen for high-affinity and broad epitope coverage, accelerating biotherapeutic discovery and de novo protein design.
View details for PubMedID 39650601
View details for PubMedCentralID PMC11623700
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Thermally induced structural evolution and nanoscale interfacial dynamics in Bi-Sb-Te layered nanostructures
MATTER
2024; 7 (10)
View details for DOI 10.1016/j.matt.2024.08.006
View details for Web of Science ID 001330881000001
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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
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Toward "super-scintillation" with nanomaterials and nanophotonics.
Nanophotonics
2024; 13 (11): 1953-1962
Abstract
Following the discovery of X-rays, scintillators are commonly used as high-energy radiation sensors in diagnostic medical imaging, high-energy physics, astrophysics, environmental radiation monitoring, and security inspections. Conventional scintillators face intrinsic limitations including a low extraction efficiency of scintillated light and a low emission rate, leading to efficiencies that are less than 10 % for commercial scintillators. Overcoming these limitations will require new materials including scintillating nanomaterials ("nanoscintillators"), as well as new photonic approaches that increase the efficiency of the scintillation process, increase the emission rate of materials, and control the directivity of the scintillated light. In this perspective, we describe emerging nanoscintillating materials and three nanophotonic platforms: (i) plasmonic nanoresonators, (ii) photonic crystals, and (iii) high-Q metasurfaces that could enable high performance scintillators. We further discuss how a combination of nanoscintillators and photonic structures can yield a "super scintillator" enabling ultimate spatio-temporal resolution while enabling a significant boost in the extracted scintillation emission.
View details for DOI 10.1515/nanoph-2023-0946
View details for PubMedID 38745841
View details for PubMedCentralID PMC11090085
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Toward "super-scintillation" with nanomaterials and nanophotonics
NANOPHOTONICS
2024
View details for DOI 10.1515/nanoph-2023-0946
View details for Web of Science ID 001201678800001
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Solution-phase sample-averaged single-particle spectroscopy of quantum emitters with femtosecond resolution.
Nature materials
2024
Abstract
The development of many quantum optical technologies depends on the availability of single quantum emitters with near-perfect coherence. Systematic improvement is limited by a lack of understanding of the microscopic energy flow at the single-emitter level and ultrafast timescales. Here we utilize a combination of fluorescence correlation spectroscopy and ultrafast spectroscopy to capture the sample-averaged dynamics of defects with single-particle sensitivity. We employ this approach to study heterogeneous emitters in two-dimensional hexagonal boron nitride. From milliseconds to nanoseconds, the translational, shelving, rotational and antibunching features are disentangled in time, which quantifies the normalized two-photon emission quantum yield. Leveraging the femtosecond resolution of this technique, we visualize electron-phonon coupling and discover the acceleration of polaronic formation on multi-electron excitation. Corroborated with theory, this translates to the photon fidelity characterization of cascaded emission efficiency and decoherence time. Our work provides a framework for ultrafast spectroscopy in heterogeneous emitters, opening new avenues of extreme-scale characterization for quantum applications.
View details for DOI 10.1038/s41563-024-01855-7
View details for PubMedID 38589542
View details for PubMedCentralID 5615041
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Accelerating Quantum Materials Development with Advances in Transmission Electron Microscopy.
Chemical reviews
2023
Abstract
Quantum materials are driving a technology revolution in sensing, communication, and computing, while simultaneously testing many core theories of the past century. Materials such as topological insulators, complex oxides, superconductors, quantum dots, color center-hosting semiconductors, and other types of strongly correlated materials can exhibit exotic properties such as edge conductivity, multiferroicity, magnetoresistance, superconductivity, single photon emission, and optical-spin locking. These emergent properties arise and depend strongly on the material's detailed atomic-scale structure, including atomic defects, dopants, and lattice stacking. In this review, we describe how progress in the field of electron microscopy (EM), including in situ and in operando EM, can accelerate advances in quantum materials and quantum excitations. We begin by describing fundamental EM principles and operation modes. We then discuss various EM methods such as (i) EM spectroscopies, including electron energy loss spectroscopy (EELS), cathodoluminescence (CL), and electron energy gain spectroscopy (EEGS); (ii) four-dimensional scanning transmission electron microscopy (4D-STEM); (iii) dynamic and ultrafast EM (UEM); (iv) complementary ultrafast spectroscopies (UED, XFEL); and (v) atomic electron tomography (AET). We describe how these methods could inform structure-function relations in quantum materials down to the picometer scale and femtosecond time resolution, and how they enable precision positioning of atomic defects and high-resolution manipulation of quantum materials. For each method, we also describe existing limitations to solve open quantum mechanical questions, and how they might be addressed to accelerate progress. Among numerous notable results, our review highlights how EM is enabling identification of the 3D structure of quantum defects; measuring reversible and metastable dynamics of quantum excitations; mapping exciton states and single photon emission; measuring nanoscale thermal transport and coupled excitation dynamics; and measuring the internal electric field and charge density distribution of quantum heterointerfaces- all at the quantum materials' intrinsic atomic and near atomic-length scale. We conclude by describing open challenges for the future, including achieving stable sample holders for ultralow temperature (below 10K) atomic-scale spatial resolution, stable spectrometers that enable meV energy resolution, and high-resolution, dynamic mapping of magnetic and spin fields. With atomic manipulation and ultrafast characterization enabled by EM, quantum materials will be poised to integrate into many of the sustainable and energy-efficient technologies needed for the 21st century.
View details for DOI 10.1021/acs.chemrev.2c00917
View details for PubMedID 37979189
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Rapid genetic screening with high quality factor metasurfaces.
Nature communications
2023; 14 (1): 4486
Abstract
Genetic analysis methods are foundational to advancing personalized medicine, accelerating disease diagnostics, and monitoring the health of organisms and ecosystems. Current nucleic acid technologies such as polymerase chain reaction (PCR) and next-generation sequencing (NGS) rely on sample amplification and can suffer from inhibition. Here, we introduce a label-free genetic screening platform based on high quality (high-Q) factor silicon nanoantennas functionalized with nucleic acid fragments. Each high-Q nanoantenna exhibits average resonant quality factors of 2,200 in physiological buffer. We quantitatively detect two gene fragments, SARS-CoV-2 envelope (E) and open reading frame 1b (ORF1b), with high-specificity via DNA hybridization. We also demonstrate femtomolar sensitivity in buffer and nanomolar sensitivity in spiked nasopharyngeal eluates within 5 minutes. Nanoantennas are patterned at densities of 160,000 devices per cm2, enabling future work on highly-multiplexed detection. Combined with advances in complex sample processing, our work provides a foundation for rapid, compact, and amplification-free molecular assays.
View details for DOI 10.1038/s41467-023-39721-w
View details for PubMedID 37495593
View details for PubMedCentralID PMC10372074
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Through thick and thin: how optical cavities control spin.
Nanophotonics (Berlin, Germany)
2023; 12 (14): 2779-2788
Abstract
When light interacts with matter by means of scattering and absorption, we observe the resulting color. Light also probes the symmetry of matter and the result is encoded in its polarization. In the special case of circularly-polarized light, which is especially relevant in nonlinear optics, quantum photonics, and physical chemistry, a critical dimension of symmetry is along the longitudinal direction. We examine recent advances in controlling circularly-polarized light and reveal that the commonality in these advances is in judicious control of longitudinal symmetry. In particular, in the use of high quality-factor modes in dielectric metasurfaces, the finite thickness can be used to tune the modal profile. These symmetry considerations can be applied in multiplexed optical communication schemes, deterministic control of quantum emitters, and sensitive detection of the asymmetry of small molecules.
View details for DOI 10.1515/nanoph-2023-0175
View details for PubMedID 39635484
View details for PubMedCentralID PMC11501721
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Through thick and thin: how optical cavities control spin
NANOPHOTONICS
2023
View details for DOI 10.1515/nanoph-2023-0175
View details for Web of Science ID 000982262200001
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Double-Bilayer polar nanoregions and Mn antisites in (Ca, Sr)3Mn2O7.
Nature communications
2022; 13 (1): 4927
Abstract
The layered perovskite Ca3Mn2O7 (CMO) is a hybrid improper ferroelectric candidate proposed for room temperature multiferroicity, which also displays negative thermal expansion behavior due to a competition between coexisting polar and nonpolar phases. However, little is known about the atomic-scale structure of the polar/nonpolar phase coexistence or the underlying physics of its formation and transition. In this work, we report the direct observation of double bilayer polar nanoregions (db-PNRs) in Ca2.9Sr0.1Mn2O7 using aberration-corrected scanning transmission electron microscopy (S/TEM). In-situ TEM heating experiments show that the db-PNRs can exist up to 650°C. Electron energy loss spectroscopy (EELS) studies coupled with first-principles calculations demonstrate that the stabilization mechanism of the db-PNRs is directly related to an Mn oxidation state change (from 4+ to 2+), which is linked to the presence of Mn antisite defects. These findings open the door to manipulating phase coexistence and achieving exotic properties in hybrid improper ferroelectric.
View details for DOI 10.1038/s41467-022-32090-w
View details for PubMedID 35995791
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Rapid genetic screening with high quality factor metasurfaces.
ArXiv
2021
Abstract
Genetic analysis methods are foundational to advancing personalized and preventative medicine, accelerating disease diagnostics, and monitoring the health of organisms and ecosystems. Current nucleic acid technologies such as polymerase chain reaction (PCR), next-generation sequencing (NGS), and DNA microarrays rely on fluorescence and absorbance, necessitating sample amplification or replication and leading to increased processing time and cost. Here, we introduce a label-free genetic screening platform based on high quality (high-Q) factor silicon nanoantennas functionalized with monolayers of nucleic acid fragments. Each nanoantenna exhibits substantial electromagnetic field enhancements with sufficiently localized fields to ensure isolation from neighboring resonators, enabling dense biosensor integration. We quantitatively detect complementary target sequences using DNA hybridization simultaneously for arrays of sensing elements patterned at densities of 160,000 pixels per cm$^2$. In physiological buffer, our nanoantennas exhibit average resonant quality factors of 2,200, allowing detection of two gene fragments, SARS-CoV-2 envelope (E) and open reading frame 1b (ORF1b), down to femtomolar concentrations. We also demonstrate high specificity sensing in clinical nasopharyngeal eluates within 5 minutes of sample introduction. Combined with advances in biomarker isolation from complex samples (e.g., mucus, blood, wastewater), our work provides a foundation for rapid, compact, amplification-free and high throughput multiplexed genetic screening assays spanning medical diagnostics to environmental monitoring.
View details for PubMedID 34671699
View details for PubMedCentralID PMC8528080