Understanding Diffusion in a Single-Metal Organic Framework Crystal Used for Sensing Applications.

Metal-organic frameworks (MOFs) stand out as remarkable materials renowned for their exceptionally high surface area and large number of pores, making them invaluable for diverse sensing applications including gas, biomedical, chemical, and optical sensing. Traditional methods of molecule infusion and release often involve a large number of crystals with varying shapes and sizes, leading to averaged outcomes across a heterogeneous crystal population. In this study, we present continuous monitoring of the infusion and release dynamics of model drug molecules, specifically vitamin B, within individual Tb-mesoMOF crystals.

Mobile ELISA with a Transparent Incubator.

Enzyme-linked immunosorbent assay (ELISA) is one of the most important technologies for biochemical testing critical for diagnosis and monitoring of many diseases. Traditional systems for ELISA incubation and reading are expensive and bulky, thus cannot be used at point-of-care or in the field. Here, we designed and demonstrated a new miniature mobile phone-based system for ELISA.

Simulations and experimental demonstration of three different regimes of optofluidic manipulation.

It has been demonstrated that optically controlled microcurrents can be used to capture and move around a variety of microscopic objects ranging from cells and nanowires to whole live worms. Here, we present our findings on several new regimes of optofluidic manipulation that can be engineered using careful design of microcurrents. We theoretically optimize these regimes using COMSOL Multiphysics and present three sets of simulations and corresponding optofluidic experiments.

Innovative optofluidics and microscopy-based rapid analysis of pathogens.

The timely knowledge and prescription of the most suitable antibiotic to treat bacterial infections is critical for the recovery of patients battling life-threatening bacterial infections. Unfortunately, current standard-of-care approaches relies on the empiric prescription of an antibiotic, as determination of the most effective antibiotic requires multiple time-consuming steps. These steps often include culturing of the bacterium responsible for infection and subsequent antibiotic susceptibility testing.

Different Regimes of Opto-fluidics for Biological Manipulation.

Metallic structures can be used for the localized heating of fluid and the controlled generation of microfluidic currents. Carefully designed currents can move and trap small particles and cells. Here we demonstrate a new bi-metallic substrate that allows much more powerful micro-scale manipulation.

Plasmono-magnetic material for precise photothermal heating.

Noble metal nanoparticles have been extensively studied as photo-sensitive agents for photothermal cancer therapy. Precise control over the size and shape of the nanoparticles allowed strong optical absorption and efficient heat generation necessary for destroying a tumor to be achieved. However, one of the fundamental challenges of application of the nanoparticles towards photothermal cancer therapy is low specificity in the targeting tumor tissue in comparison with the healthy tissue and the resulting unfavorable biodistribution of the nanoparticles.

Mobile phone based ELISA (MELISA).

Enzyme-linked immunosorbent assay (ELISA) is one of the most important technologies for biochemical analysis critical for diagnosis and monitoring of many diseases. Traditional systems for ELISA incubation and reading are expensive and bulky, thus cannot be used at point-of-care or in the field. Here, we propose and demonstrate a new miniature mobile phone based system for ELISA (MELISA).

Measurement of thickness of highly inhomogeneous crude oil slicks.

As part of the Deepwater Horizon toxicity testing program, a number of laboratories generated oil slicks in the laboratory to study potential toxic effects of these oil slicks on aquatic organisms. Understanding the details of how these slicks affect aquatic organisms requires careful correlation between slick thickness and the observed detrimental effects. Estimating oil film thickness on water can be challenging since the traditional color-based technique used in the field is very imprecise.

Dynamic visualization of photothermal heating by gold nanocages using thermoresponsive elastin like polypeptides.

Understanding how plasmonic nanoparticles collectively generate heat upon exposure to light and thus increase the local temperature of the surrounding medium is critical for many applications such as plasmon-assisted microfluidics, plasmonic tweezers, and photothermal cancer therapy. Reliable temperature manipulation requires the capability to spatially and dynamically analyze local temperature profiles as a function of nanoparticle concentration and laser intensity. In this work, we present a novel method for visualization of local temperature increase using elastin-like polypeptides (ELP).

Subcellular and in-vivo Nano-Endoscopy.

Analysis of individual cells at the subcellular level is important for understanding diseases and accelerating drug discovery. Nanoscale endoscopes allow minimally invasive probing of individual cell interiors. Several such instruments have been presented previously, but they are either too complex to fabricate or require sophisticated external detectors because of low signal collection efficiency.

A mobile phone-based approach to detection of hemolysis.

Preeclampsia and HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome are pregnancy-related complications with high rates of morbidity and mortality. HELLP syndrome, in particular, can be difficult to diagnose. Recent work suggests that elevated levels of free cell hemoglobin in blood plasma can, as early as the first trimester, potentially serve as a diagnostic biomarker for impending complications.

Statistical Analysis of Photonic Crystal Spectra for the Independent Determination of the Size and Refractive Index of Cells.

Photonic crystal flow cytometry is a very attractive platform due to its great sensitivity in combination with a very compact design. Previous studies have demonstrated the possibility to use spectral processing for the measurement of a wide range of parameters, from simple object counting to independent analysis of the buffer solution and immersed microscale objects. Here we propose to go to the next level and simultaneously determine the shape and the refractive index of the cells.

Optimization of dry etching parameters for fabrication of polysilicon waveguides with smooth sidewall using a capacitively coupled plasma reactor.

In this paper, we demonstrate the optimization of a capacitively coupled plasma etching for the fabrication of a polysilicon waveguide with smooth sidewalls and low optical loss. A detailed experimental study on the influences of RF plasma power and chamber pressure on the roughness of the sidewalls of waveguides was conducted and waveguides were characterized using a scanning electron microscope. It was demonstrated that optimal combination of pressure (30 mTorr) and power (150 W) resulted in the smoothest sidewalls.

Photonic crystal based microscale flow cytometry.

Here we propose a new design of an on-chip micro-flow cytometry based on photonic crystals. When individual cells flow tangential to the crystal surface, the transmission of the light through the photonic crystal changes depending on the presence or absence of the cells and their size and shape. This system was modeled using OptiFDTD, where transmission spectra were extracted.

Optimization of light delivery by a nanowire-based single cell optical endoscope.

Here we present a new design and FDTD simulations of light delivery by a nanowire-based intracellular endoscope. Nanowires can be used for minimally invasive and very local light delivery inside cells. One of the main challenges is coupling of light into the nanowire.

Field-induced guiding optical devices made from electro-optic polymers.

Field-induced guiding (FIG) has been known for several decades. Many advanced optical FIG devices (light modulators, splitters, scanners, etc.) were proposed, but due to high fabrication cost and/or high operation voltages they were considered impractical.

Nanoengineered optical resonance sensor for composite material refractive-index measurements.

We present an optical resonance sensor capable of measurement of refractive index in highly nonhomogeneous materials. Traditional optical resonance sensors fail when the size of particles is comparable with the wavelength (100 nm and larger). Our new nanoengineered design allows incorporation of a highly delocalized mode into a resonance structure.

Integration of photonic and silver nanowire plasmonic waveguides.

Future optical data transmission modules will require the integration of more than 10,000 x 10,000 input and output channels to increase data transmission rates and capacity. This level of integration, which greatly exceeds that of a conventional diffraction-limited photonic integrated circuit, will require the use of waveguides with a mode confinement below the diffraction limit, and also the integration of these waveguides with diffraction-limited components. We propose to integrate multiple silver nanowire plasmonic waveguides with polymer optical waveguides for the nanoscale confinement and guiding of light on a chip.