With current concerns of antibiotic-resistant bacteria and biodefense, it has become important to rapidly identify infectious bacteria. Traditional technologies involving isolation amplification the pathogenic are time-consuming. We report a rapid simple method that combines in vivo biotinylation engineered host-specific bacteriophage conjugation phage streptavidin-coated quantum dots. The provides specific detection as few 10 bacterial cells per milliliter experimental samples, with an...

SignificanceDevelopments of anti-gametocyte drugs have been delayed due to insufficient understanding gametocyte biology. We report a systematic workflow data processing algorithms quantify changes in the absorption spectrum and cell morphology single malaria-infected erythrocytes. These may serve as biomarkers instrumental for future development antimalarial strategies, especially drug design testing. Image-based also be useful nondestructive, label-free malaria detection efficacy...

Near-field scanning optical microscopy (NSOM) uses the near-field interaction of light from a sharp fiber-optic probe with sample interest to image surfaces at resolution beyond diffraction limit conventional optics. We used NSOM fluorescently labeled plasma membranes fixed human skin fibroblasts, either dried or in buffer. A patchy distribution fluorescent lipid analog suggestive domains was observed fixed, cells. The sizes these patches were consistent implied by fluorescence...

Near-field scanning optical microscopy of phospholipid monolayers doped with fluorescent lipid analogs reveals previously undescribed features in various phases, including a concentration gradient at the liquid-expanded/liquid-condensed domain boundary and weblike structures solid-condensed phase. Presumably, web are grain boundaries between crystalline solid lipid. These strongly modulated by addition low concentrations cholesterol ganglioside G M1 monolayer.

Research involving bacterial pathogens often requires enumeration of bacteria colonies. Here, we present a low-cost, high-throughput colony counting system consisting software and consumer-grade digital camera or document scanner. We demonstrate that this software, called "NICE" (NIST's Integrated Colony Enumerator), can count colonies as part multiplexed opsonophagocytic killing assay used to characterize pneumococcal vaccine efficacy. The results obtained with NICE correlate well the from...

Localized measurements of scattering in biological tissue provide sensitivity to microstructural morphology but have limited utility wide-field applications, such as surgical guidance. This study introduces sub-diffusive spatial frequency domain imaging (sd-SFDI), which uses high illumination achieve sampling localized reflectances. Model-based inversion recovers macroscopic variations the reduced coefficient [Formula: see text] and phase function backscatter parameter (γ). Measurements...

We report the development of an optically transparent high-frequency ultrasonic transducer using lithium niobate single-crystal and indium-tin-oxide electrodes with up to 90% optical transmission in visible-to-near-infrared spectrum. The center frequency was at 36.9 MHz 33.9%, -6 dB fractional bandwidth. photoacoustic imaging capability fabricated also demonstrated by successfully a resolution target mouse-ear vasculatures vivo, which were irradiated 532 nm pulse laser transmitted through transducer.

Abstract Spectrally resolved photoacoustic imaging is promising for label-free in optically scattering materials. However, this technique often requires acquisition of a separate image at each wavelength interest. This reduces speeds and causes errors if the sample changes time between images acquired different wavelengths. We demonstrate solution to problem by using dual-comb spectroscopy measurements. approach enables measurement thousands wavelengths simultaneously. In technique, two...

The molecular stability of hemoglobin is critical for normal erythrocyte functions, including oxygen transport. Hemoglobin C (HbC) a mutant that has increased oxidative susceptibility due to an amino acid substitution (beta6: Glu Lys). growth Plasmodium falciparum abnormal in homozygous CC erythrocytes vitro, and individuals show innate protection against severe P. malaria. We investigated one possible mechanism using quantum dot technique compare the distribution host membrane band 3...

ABSTRACT Plasmodium falciparum (Pf) infection remodels the human erythrocyte with new membrane systems, including a modified host (EM), parasitophorous vacuole (PVM), tubulovesicular network (TVN), and Maurer's clefts (MC). Here we report on relative cholesterol contents of these membranes in parasitized normal (HbAA) hemoglobin S-containing (HbAS, HbAS) erythrocytes. Results from fluorescence lifetime imaging microscopy (FLIM) experiments cholesterol-sensitive fluorophore show that levels...

Abstract We characterize CdSe/ZnS quantum dot (QD) binding to genetically modified bacteriophage as a model for bacterial detection. Interactions among QDs, lambda (λ) phage, and Escherichia coli are examined by several cross‐validated methods. Flow image‐based cytometry clarify fluorescent labeling of bacteria, with additionally reporting the number decorated phage bound cells. Transmission electron microscopy, cytometry, electrospray differential mobility analysis allow quantization QDs...

Blinking of zinc blende CdSe-based core/shell nanocrystals is studied as a function shell materials and surface ligands. CdSe/ZnS, CdSe/ZnSe/ZnS CdSe/CdS/ZnS are prepared by colloidal synthesis six monolayers larger bandgap grown over the CdSe core. Organic-soluble covered with stearate made water-soluble ligand exchange 3-mercaptopropionic acid. The light-emitting states characterized absorption emission spectroscopy well photoluminescence lifetime measurements in solution. blinking time...

A new nanomaterial conjugation technique is presented to effectively bind semiconductor quantum dots (QDs) onto single-walled carbon nanotubes (SWCNTs) via covalent amidation, employing single-stranded DNA oligonucleotides as linkers (see schematic and AFM image). This provides a measurement platform for the study of their interactions involving photoinduced charge transfer between QDs SWCNTs at nanoscale.

The editors introduce the Biomedical Optics Express feature issue on "Phantoms for Performance Evaluation and Validation of Optical Medical Imaging Devices." This topic was focus a technical workshop that held November 7-8, 2011, in Washington, D.C. includes 13 contributions from attendees.

We report an absorption-based hyperspectral imaging and analysis technique to resolve unique physicochemical characteristics of subcellular substances in single erythrocytes. constructed a microscope system installed with spectral light engine capable controlling the shape illumination by digital micromirror device. The sequential maximum angle convex cone algorithm allow us extract signatures (i.e., endmembers) for different types hemoglobin, such as oxyhemoglobin, methemoglobin, hemozoin,...

Hyperspectral imaging has the potential to achieve high spatial resolution and functional sensitivity for non-invasive assessment of tissue oxygenation. However, clinical acceptance hyperspectral in ischemic wound is hampered by its poor reproducibility, low accuracy, misinterpreted biology. These limitations are partially caused lack a traceable calibration standard. We proposed digital phantom (DTP) platform quantitative performance evaluation spectral devices. The technical feasibility...

There is a need for common reference point that will allow the comparison of optical properties tissue-mimicking phantoms. After brief review methods have been used to measure phantoms contextual backdrop our approach, this paper reports on establishment standardized double-integrating-sphere platform absorption and reduced scattering coefficients biomedical The implements user-friendly graphical user interface in which variations experimental configurations model-based analysis are...

We present broadband measurements of the optical properties tissue-mimicking solid phantoms using a single integrating sphere to measure hemispherical reflectance and transmittance under direct illumination at normal incident angle. These are traceable scales. An inversion routine output adding-doubling algorithm restricted was developed produce parameters sample along with an uncertainty budget each wavelength. The results for two types compared by time-resolved approaches. between our...

Significance: The polymer, polydimethylsiloxane (PDMS), has been increasingly used to make tissue simulating phantoms due its excellent processability, durability, flexibility, and limited tunability of optical, mechanical, thermal properties. We report on a robust technique fabricate PDMS-based tissue-mimicking where the broad range scattering absorption properties are independently adjustable in visible- near-infrared wavelength from 500 850 nm. also an analysis method concisely quantify...

Hyperspectral dark-field microscopy (HSDFM) and data cube analysis algorithms demonstrate successful detection classification of various tissue types, including carcinoma regions in human post-lumpectomy breast tissues excised during breast-conserving surgeries.