This PDF file contains the front matter associated with SPIE Proceedings Volume 9337, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

Hyperspectral imaging can provide accurate information on the distribution of the chemical species in materials and biological samples, based on the analysis of their electronic and vibrational profiles. In special, confocal Raman microscopy is one of the best ways to access the chemical distribution of molecules, especially under resonance Raman or SERS conditions. On the other hand, enhanced dark field optical microscopy can be employed for hyperspectral imaging in the visible and near-IR region, while extending the optical resolution up to the nanoscale dimension. It allows the detection of gold or silver single nanoparticles, as well as spectral monitoring from the characteristic surface plasmon bands. These two hyperspectral microscopies can be conveniently combined to provide nanoscale electronic and vibrational information of the species present in a wide variety of chemical and biological systems. A case study focusing on the improvement of the classical spot-test analysis of nickel(II) ions with dithizone is here detailed. A great enhancement of sensitivity in the detection of nickel(II) ions, by at least 4 orders of magnitude, has been observed in this work. Hyperspectral measurements allowed the mapping of the gold nanoparticles (AuNP) distribution on cellulose fibers and on glass, and the evaluation of their extinction and SERS spectra for analytical purposes.

We demonstrate localized magnetometry using a single nitrogen vacancy (NV) center in the microfluidic devices. Our approach enables three dimensional manipulation of a magnetic object in solution with nanoscale spatial accuracy, and also enables us to orient its dipole moment. A diamond nanocrystal is integrated into the microfluidic device and serves as a local magnetic field probe. We vary the position of a magnetic object in liquid and map out its magnetic field distribution by perform continuous electron spin resonance (ESR) measurement on the NV center. These results open up the possibility for using NV centers as nanosized magnetometers with high sensitivity in microfluidic device for applications in chemical sensing, biological sensing and microscopy.

Optical super-resolution imaging is a desirable technique in many fields, including medical and material sciences and nanophotonics. We demonstrated feasibility of optical microscopy, with resolution improvement by a factor of 2-3, by using microsphere-embedded coverslips composed of barium titanate glass microspheres (refractive index n~1.9-2.1) fixed in a transparent layer of polydimethylsiloxane. Imaging was performed by a conventional microscope and a fluorescent microscope with the microsphere-embedded layer placed in a contact position with various biological specimens and semiconductor nanostructures. We investigated a biomedical application of microsphere-assisted imaging technique by immunostaining of kidney sections where cellular distribution of a motor protein Myo1c and a podocyte specific protein ZO-1 was analyzed. A significant visual enhancement in the distribution pattern of the proteins was noted in the stained glomeruli by using microsphere-assisted imaging technique. Our results suggest that microsphere-assisted imaging technique is a promising candidate for applications in medical and cancer research, as well as in microfluidics and nanophotonics.

As the most abundant protein in the human body, collagen has a very important role in vast numbers of bio-medical applications. The unique second order nonlinear properties of fibrillar collagen make it a very important index in nonlinear optical imaging based disease diagnosis of the brain, skin, liver, colon, kidney, bone, heart and other organs in the human body. The second-order nonlinear susceptibility of collagen has been explored at the macroscopic level and was explained as a volume-averaged molecular hyperpolarizability. However, details about the origin of optical second harmonic signals from collagen fibrils at the molecular level are still not clear. Such information is necessary for accurate interpolation of bio-information from nonlinear optical imaging techniques. The later has shown great potential in collagen based disease diagnosis methodologies. In this paper, we report our work using an atomic force microscope (AFM), near field (SNOM) and nonlinear laser scanning microscope (NLSM) to study the structure of collagen fibrils and other pro-collagen structures.

A super-resolved axial imaging technique was investigated based on extraordinary transmission (EOT) of light using metallic gradient nanoaperture arrays. Light through subwavelength nanoapertures at thick metal film can be transmitted and amplified by several orders of magnitude due to plasmonic coupling. Here, the feasibility of EOT-based axial imaging with super resolution is explored. Since light penetration of EOT is much deeper than that of evanescent waves, the axial range to obtain the distance information of fluorescence signals can be extended by EOT. The axial distribution of ganglioside in mouse macrophage cells was measured with sub-diffraction-limited resolution after reconstruction using differential fluorescence excitation on gradient aperture arrays.

Sequence-specific detection of DNA hybridization at the single-molecule level has been instrumental and gradually become a ubiquitous tool in a wide variety of biological and biomedical applications such as clinical diagnostics, biosensors, and drug development. Label-free and amplification-free schemes are of particular interest because they could potentially provide in situ monitoring of individual hybridization events, which may lead to techniques for discriminating subtle variations due to single-base modification without stringency control or repetitive thermal cycling. Surface-enhanced Raman spectroscopy (SERS) has been widely used for molecular detection and identification by exploiting the localized surface plasmon resonance effect when the target molecules are near gold or silver nanostructures. However, effective and robust SERS assays have yet become a reality for trace detection. Recently, we have developed a SERS substrate by shaping nanoporous gold thin films into monolithic submicron disks, called nanoporous gold disks (NPGD). Here we demonstrate in situ monitoring of the same immobilized ssDNA molecules and their individual hybridization events.

Determination of both thickness and refractive index of a thin biomolecular or polymer layer in wet conditions is a task not easily performed. Available tools such as XPS, AFM, ellipsometry and integrated photonic sensors often have difficulties with the native wet condition of said agents-under-test, perform poorly in the sub-5 nm regime or do not determine both characteristics in an absolute simultaneous way. The thickness of a multilayer system is often determined by averaging over a large amount of layers, obscuring details of the individual layers. Even more, the interesting behavior of the first bound layers can be covered in noise or assumptions might be made on either thickness or refractive index in order to determine the other. To demonstrate a solution to these problems, a silicon-on-insulator (SOI) microring is used to study the adsorption of a bilayer polymer system on the silicon surface of the ring. To achieve this, the microring is simultaneously excited with TE and TM polarized light and by tracking the shifts of both resonant wavelengths, the refractive index and the thickness of the adsorbed layer can be determined with a resolution on thickness smaller than 0.1 nm and a resolution on refractive index smaller than 0.01 RIU. An adhesive polyethyleneimine (PEI) layer is adsorbed to the surface, followed by the adsorption of poly(sodium-4-styrene sulfonate) (PSS) and poly(allylamine) hydrochloride (PAH). This high-resolution performance in wet conditions with the added benefits of the SOI microring platform such as low cost and multiplexibility make for a powerful tool to analyze thin layer systems, which is promising to research binding conformation of proteins as well.

Protein molecular motors, which convert chemical energy into kinetic energy, are prime candidates for use in nanodevice in which active transport is required. To be able to design these devices it is essential that the properties of the cytoskeletal filaments propelled by the molecular motors are well established. Here we used micro-contact printed BSA to limit the amount of HMM that can adsorb creating a tightly confined pathway for the filaments to travel. Both the image and statistical analysis of the movement of the filaments through these structures have been used to new insights into the motility behaviour of actomyosin on topographically homogenous, but motor-heterogeneous planar systems. It will be shown that it is possible to determine the persistence length of the filaments and that it is related to the amount of locally adsorbed HMM. This provides a basis that can be used to optimize the design of future nanodevices incorporating the actomyosin system for the active transport.

We presently introduce a novel generation of optical nanoprobes, based on chromium-doped zinc gallate, whose persistent luminescence can be activated in vivo through living tissues using highly penetrating low energy photons from the red region of the visible spectrum. Surface functionalization of this photonic nanoprobe can be adjusted to favor multiple challenging biomedical applications.

Biophotonic Sensing Cells (BICELLs) are demonstrated to be an efficient technology for label-free biosensing and in concrete for evaluating dry eye diseases. The main advantage of BICELLs is its capability to be used by dropping directly a tear into the sensing surface without the need of complex microfluidics systems. Among this advantage, compact Point of Care read-out device is employed with the capability of evaluating different types of BICELLs packaged on Biochip-Kits that can be fabricated by using different sensing surfaces material. In this paper, we evaluate the performance of the combination of three sensing surface materials: (3-Glycidyloxypropyl) trimethoxysilane (GPTMS), SU-8 resist and Nitrocellulose (NC) for two different biomarkers relevant for dry eye diseases: PRDX-5 and ANXA-11.

Gold nanoparticles (NPs) have tremendous potential in biomedicine. They can be used as absorbing labels inside living cells for the purpose of biomedical imaging, biosensing as well as for photothermal therapy. We demonstrate photothermal imaging of highly-absorbing particles using a pump-probe setup. The photothermal signal is recovered by heterodyne detection, where the excitation pump laser is at 532 nm and the probe laser is at 638 nm. The sample is moved by a scanning stage. Proof of concept images of red polystyrene microspheres and gold nanoparticles are obtained with this home-built multimodal microscope. The increase in temperature at the surface of the gold NPs, due to the pump laser beam, can be directly measured by means of this photothermal microscope and then compared with the results from theoretical predictions. This technique will be useful for characterization of nanoparticles of different shapes, sizes and materials that are used in cancer diagnosis and therapy.

In this work, we report using an optical tweezers system to study the light-matter interaction and gradient optical forces of porous silicon nanoparticles. The particles are fabricated by first electrochemically etching a multi-layer porous film into a silicon wafer and then breaking up the film through ultrasonic fracturing. The particles have average pore diameters ranging from 20-30 nm. The fabricated batches of particles have diameters between approximately 100- 600nm. After fabrication, the particles are size-sorted by centrifugation. A commercially available optical tweezers system is used to systematically study the optical interaction with these nanoparticles. This work opens new strategic approaches to enhance optical forces and optical sensitivity to mechanical motion that can be the basis for future biophotonics applications.