Gravitational Field of a Spinning Mass as an Example of Algebraically Special Metrics

Chemistries that Facilitate Nanotechnology Kim E. Sapsford,† W. Russ Algar, Lorenzo Berti, Kelly Boeneman Gemmill,‡ Brendan J. Casey,† Eunkeu Oh, Michael H. Stewart, and Igor L. Medintz*,‡ †Division of Biology, Department of Chemistry and Materials Science, Office of Science and Engineering Laboratories, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, United States ‡Center for Bio/Molecular Science and Engineering Code 6900 and Division of Optical Sciences Code 5611, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States College of Science, George Mason University, 4400 University Drive, Fairfax, Virginia 22030, United States Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Sacramento, California 95817, United States Sotera Defense Solutions, Crofton, Maryland 21114, United States

Functionalizing nanoparticles with biological molecules: developing chemistries that facilitate nanotechnology.

CONTENTS 1. Introduction 1.1. Fundamental Theory of Surface-Enhanced Raman Scattering 1.2. Optical Properties of SERS Tags 2. Synthesis of SERS Tags 2.1. Noble Metal Nanosubstrates 2.1.1. Single Particle-Based SERS Substrates 2.1.2. Nanoparticle Cluster-Based Substrates 2.2. Raman Reporter Molecules 2.2.1. Selection Principles and Reporter Types 2.2.2. Self-Assembled Monolayer Coverage Strategy 2.3. Surface Coating for Protection 2.3.1. Biomolecule Coating 2.3.2. Polymer Coating 2.3.3. Liposome Coating 2.3.4. Silica Coating 2.4. Attachment of Targeting Molecules 3. Bioanalysis Applications 3.1. Ionic and Molecular Detection 3.2. Pathogen Detection 3.3. Live-Cell Imaging 3.3.1. Cancer Marker Detection 3.3.2. Intercellular Microenvironment Sensing 3.4. Tissue SERS Imaging 3.5. In Vivo SERS Imaging 4. Challenges and Perspectives 4.1. Reproducible Signal of SERS Tags 4.1.1. Precisely Controlled Hot Spots for Nanosubstrates 4.1.2. Calibration of SERS Intensities and Enhancements 4.2. Improving Multiplexing Capability 4.3. Reduced Size for Subcellular Imaging 4.4. Development of Multifunctional Nanoplatforms 4.4.1. Magnetic SERS Dots 4.4.2. Multimodal Imaging Dots 4.4.3. SERS Tag-Based Therapeutic Systems 4.5. Biocompatibility 5. Conclusions and Remarks

SERS Tags: Novel Optical Nanoprobes for Bioanalysis

Introduction A Why POC Diagnostics? B Time B Patient Responsibility and Compliance B Cost B Diagnostic Targets C Proteins C Metabolites and Other Small Molecules C Nucleic Acids C Human Cells D Microbes/Pathogens D Drugs and Food Safety D Current Context of POC Assays E POC Glucose Assays E Lateral Flow Assays E Limitations of “Traditional” POC Approaches F Enabling Technologies G Printing and Laminating G Microfluidic Technologies and Approaches: “Unit Operations” for POC Devices G Pumping and Valving H Mixing I Separation I Reagent Storage J Sample Preparation K Surface Chemistry and Device Substrates L Physical Adsorption L Bioaffinity Attachment L Covalent Attachment M Substrate Materials M Detection M Electrochemical Detection N Optical Detection N Magnetic Detection N Label-Free Methods O Enabling Multiplexed Assays O Recent Innovation O Lateral Flow Assay Technologies O Proteins P Antibodies P Protein Expression and Purification Q Nucleic Acids Q Aptamers R Infectious Diseases and Food/Water Safety R Blood Chemistry S Coagulation Markers S Whole Cells S Trends, Unmet Needs, Perspectives T Glucose T Global Health and the Developing World T Personalized Medicine and Home Testing U Technology Trends U Multiplexing V Author Information V Biographies V Acknowledgment W References W

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Point of care diagnostics: Status and future

Nanoantennas for visible and infrared radiation can strongly enhance the interaction of light with nanoscale matter by their ability to efficiently link propagating and spatially localized optical fields. This ability unlocks an enormous potential for applications ranging from nanoscale optical microscopy and spectroscopy over solar energy conversion, integrated optical nanocircuitry, opto-electronics and density-of-states engineering to ultra-sensing as well as enhancement of optical nonlinearities. Here we review the current understanding of metallic optical antennas based on the background of both well-developed radiowave antenna engineering and plasmonics. In particular, we discuss the role of plasmonic resonances on the performance of nanoantennas and address the influence of geometrical parameters imposed by nanofabrication. Finally, we give a brief account of the current status of the field and the major established and emerging lines of investigation in this vivid area of research.

https://iopscience.iop.org/article/10.1088/0034-4885/75/2/024402/pdf

Nanoantennas for visible and infrared radiation.

We present a self-powered integrated microfluidic blood analysis system (SIMBAS) that does not require any external connections, tethers, or tubing to deliver and analyze a raw whole-blood sample. SIMBAS only requires the user to place a 5 μL droplet of whole-blood at the inlet port of the device, whereupon the stand-alone SIMBAS performs on-chip removal of red and white cells, without external valving or pumping mechanisms, followed by analyte detection in platelet-containing plasma. Five complete biotin–streptavidin sample-to-answer assays are performed in 10 min; the limit of detection is 1.5 pM. Red and white blood cells are removed by trapping them in an integral trench structure. Simulations and experimental data show 99.9% to 100% blood cell retention in the passive structure. Powered by pre-evacuation of its PDMS substrate, SIMBAS' guiding design principle is the integration of the minimal number of components without sacrificing effectiveness in performing rapid complete bioassays, a critical step towards point-of-care molecular diagnostics.

Stand-alone self-powered integrated microfluidic blood analysis system (SIMBAS)

Bioinspired nanocorals with decoupled cellular targeting and sensing functionality.

We present the first optical study of large-area random arrays of crescent-shaped nanoholes. The crescent-shaped nanohole antennae, fabricated using wafer-scale nanosphere lithography, provide a complement to crescent-shaped nanostructures, called nanocrescents, which have been established as powerful plasmonic biosensors. With both systematic experimental and computational analysis, we characterize the optical properties of crescent-shaped nanohole antennae and demonstrate tunability of their optical response by varying all key geometric parameters. Crescent-shaped nanoholes have reproducible sub-10-nm tips and are sharper than corresponding nanocrescents, resulting in higher local field enhancement, which is predicted to be |E|/|E(0)| = 1500. In addition, the crescent-shaped nanohole hole-based geometry offers increased integratability and the potential to nanoconfine analyte in "hot-spot" regions, increasing biomolecular sensitivity and allowing localized nanoscale optical control of biological functions.

Optical properties of the crescent-shaped nanohole antenna.

With a systematic comparison of the near- and far-field measures of plasmon resonance, we show that significant differences arise between the measures for both gold and silver spherical particles. The difference of the peak wavelengths between the near- and far-field measures increases with increasing particle size, reaching over 200 nm for a particle radius of 100 nm for both gold and silver. We physically explain these results by applying radiation damping to the quasi-static approximation, and we provide simple phenomenonological fits, which readily convert between the peak wavelengths for each measure. We expect that taking into account these differences can provide improvement in understanding and optimizing surface-enhanced spectroscopies.

Comparison of near- and far-field measures for plasmon resonance of metallic nanoparticles

We present a systematic numerical study of plasmon resonance of the nanocrescent. We show that by varying the nanocrescent geometry, the plasmon resonance peak can be tuned into the near-infrared and local field enhancement can be increased significantly, with maximum enhancement of the electric field amplitude of approximately 100 for realistic geometric parameters. Because of its wide tunability, high local field enhancement, and geometry which utilizes both sharp features and intra-particle coupling, the nanocrescent is a structure well suited for in vivo cellular imaging as well as in vitro diagnostic applications.

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Benjamin M. Ross

Papers

Stand-alone self-powered integrated microfluidic blood analysis system (SIMBAS)

Bioinspired nanocorals with decoupled cellular targeting and sensing functionality.

Optical properties of the crescent-shaped nanohole antenna.

Comparison of near- and far-field measures for plasmon resonance of metallic nanoparticles

Plasmon tuning and local field enhancement maximization of the nanocrescent