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Inverse design of metasurfaces with non-local interactions

Cai, Haogang; Srinivasan, Srilok; Czaplewski, David A.; Martinson, Alex B.F.; Gosztola, David J.; Stan, Liliana; Loeffler, Troy; Sankaranarayanan, Subramanian K.R.S.; López, Daniel
Conventional metasurfaces have demonstrated efficient wavefront manipulation by using thick and high-aspect-ratio nanostructures in order to eliminate interactions between adjacent phase-shifter elements. Thinner-than-wavelength dielectric metasurfaces are highly desirable because they can facilitate fabrication and integration with both electronics and mechanically tunable platforms. Unfortunately, because their constitutive phase-shifter elements exhibit strong electromagnetic coupling between neighbors, the design requires a global optimization methodology that considers the non-local interactions. Here, we propose a global evolutionary optimization approach to inverse design non-local metasurfaces. The optimal designs are experimentally validated, demonstrating the highest efficiencies for the thinnest transmissive metalenses reported to-date for visible light. In a departure from conventional design methods based on the search of a library of pre-determined and independent meta-atoms, we take full advantage of the strong interactions among nanoresonators to improve the focusing efficiency of metalenses and demonstrate that efficiency improvements can be obtained by lowering the metasurface filling factors.
SCOPUS:85089020432
ISSN: 2057-3960
CID: 4578932

The CAR T-Cell Mechanoimmunology at a Glance

Li, Rui; Ma, Chao; Cai, Haogang; Chen, Weiqiang
Chimeric antigen receptor (CAR) T-cell transfer is a novel paradigm of adoptive T-cell immunotherapy. When coming into contact with a target cancer cell, CAR T-cell forms a nonclassical immunological synapse with the cancer cell and dynamically orchestrates multiple critical forces to commit cytotoxic immune function. Such an immunologic process involves a force transmission in the CAR and a spatiotemporal remodeling of cell cytoskeleton to facilitate CAR activation and CAR T-cell cytotoxic function. Yet, the detailed understanding of such mechanotransduction at the interface between the CAR T-cell and the target cell, as well as its molecular structure and signaling, remains less defined and is just beginning to emerge. This article summarizes the basic mechanisms and principles of CAR T-cell mechanoimmunology, and various lessons that can be comparatively learned from interrogation of mechanotransduction at the immunological synapse in normal cytotoxic T-cell. The recent development and future application of novel bioengineering tools for studying CAR T-cell mechanoimmunology is also discussed. It is believed that this progress report will shed light on the CAR T-cell mechanoimmunology and encourage future researches in revealing the less explored yet important mechanosensing and mechanotransductive mechanisms involved in CAR T-cell immuno-oncology.
PMCID:7740088
PMID: 33344135
ISSN: 2198-3844
CID: 4726682

Integrin nanoclusters can bridge thin matrix fibres to form cell-matrix adhesions

Changede, Rishita; Cai, Haogang; Wind, Shalom J; Sheetz, Michael P
Integrin-mediated cell-matrix adhesions are key to sensing the geometry and rigidity of extracellular environments and influence vital cellular processes. In vivo, the extracellular matrix is composed of fibrous arrays. To understand the fibre geometries that are required for adhesion formation, we patterned nanolines of various line widths and arrangements in single, crossing or paired arrays with the integrin-binding peptide Arg-Gly-Asp. Single thin lines (width ≤30 nm) did not support cell spreading or formation of focal adhesions, despite the presence of a high density of Arg-Gly-Asp, but wide lines (>40 nm) did. Using super-resolution microscopy, we observed stable, dense integrin clusters formed on parallel (within 110 nm) or crossing thin lines (mimicking a matrix mesh) similar to those on continuous substrates. These dense clusters bridged the line pairs by recruiting activated but unliganded integrins, as verified by integrin mutants unable to bind ligands that coclustered with ligand-bound integrins when present in an active extended conformation. Thus, in a fibrous extracellular matrix mesh, stable integrin nanoclusters bridge between thin (≤30 nm) matrix fibres and bring about downstream consequences of cell motility and growth.
PMID: 31477904
ISSN: 1476-1122
CID: 4261022

Ultrathin transmissive metasurfaces for multi-wavelength optics in the visible

Cai, Haogang; Czaplewski, David; Ogando, Karim; Martinson, Alex; Gosztola, David; Stan, Liliana; Lopez, Daniel
ISI:000459554300006
ISSN: 0003-6951
CID: 4261032

Full control of ligand positioning reveals spatial thresholds for T cell receptor triggering

Cai, Haogang; Muller, James; Depoil, David; Mayya, Viveka; Sheetz, Michael P; Dustin, Michael L; Wind, Shalom J
Elucidating the rules for receptor triggering in cell-cell and cell-matrix contacts requires precise control of ligand positioning in three dimensions. Here, we use the T cell receptor (TCR) as a model and subject T cells to different geometric arrangements of ligands, using a nanofabricated single-molecule array platform. This comprises monovalent TCR ligands anchored to lithographically patterned nanoparticle clusters surrounded by mobile adhesion molecules on a supported lipid bilayer. The TCR ligand could be co-planar with the supported lipid bilayer (2D), excluding the CD45 transmembrane tyrosine phosphatase, or elevated by 10 nm on solid nanopedestals (3D), allowing closer access of CD45 to engaged TCR. The two configurations resulted in different T cell responses, depending on the lateral spacing between the ligands. These results identify the important contributions of lateral and axial components of ligand positioning and create a more complete foundation for receptor engineering for immunotherapy.
PMCID:6035778
PMID: 29713075
ISSN: 1748-3395
CID: 3056522

Digitally designed ultrathin metasurfaces for multi-wavelength optics in the visible [Meeting Abstract]

Cai, Haogang; Czaplewski, David; Ogando, Karim; Martinson, Alex; Gosztola, David; Stan, Liliana; Lopez, Daniel
ISI:000454732000005
ISSN: 2160-5033
CID: 4261212

Optical fiber-based Laser Confocal Microscope with a Metalens [Meeting Abstract]

Zhen, Qiu; Lopez, Daniel; Cai, Haogang; Piyawattanametha, Wibool
ISI:000454732000041
ISSN: 2160-5033
CID: 4261222

Spatial Control of Biological Ligands on Surfaces Applied to T Cell Activation

Cai, Haogang; Depoil, David; Muller, James; Sheetz, Michael P; Dustin, Michael L; Wind, Shalom J
In this chapter, we present techniques, based on molecular-scale nanofabrication and selective self-assembly, for the presentation of biomolecules of interest (ligands, receptors, etc.) on a surface with precise spatial control and arbitrary geometry at the single-molecule level. Metallic nanodot arrays are created on glass coverslips and are then used as anchors for the immobilization of biological ligands via thiol linking chemistry. The nanodot size is controlled by both lithography and metallization. The reagent concentration in self-assembly can be adjusted to ensure single-molecule occupancy for a given dot size. The surrounding glass is backfilled by a protein-repellent layer to prevent nonspecific adsorption. Moreover, bifunctional surfaces are created, whereby a second ligand is presented on the background, which is frequently a requirement for simulating complex cellular functions involving more than one key ligand. This platform serves as a novel and powerful tool for molecular and cellular biology, e.g., to study the fundamental mechanisms of receptor-mediated signaling.
PMID: 28255709
ISSN: 1940-6029
CID: 2471612

Phase control through Huygens' metasurfaces [Meeting Abstract]

Czaplewski, David A.; Cai, Haogang; Roy, Tapashree; Ogando, Karim; Stan, Liliana; Lopez, Daniel
ISI:000426984000024
ISSN: 2160-5033
CID: 4261192

High-efficiency, low-aspect-ratio planar lens based on Huygens resonators [Meeting Abstract]

Cai, Haogang; Czaplewski, David A.; Stan, Liliana; Lopez, Daniel
ISI:000426984000025
ISSN: 2160-5033
CID: 4261202