This PDF file contains the front matter associated with SPIE Proceedings Volume 12860, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

The quantification of human immunodeficiency virus at point of care remains a challenge in resource limited settings. The incorporation of nanotechnology and label free optical biosensing has unlocked promising opportunities in the development of diagnostic tools for infectious diseases. Optical biosensors offer a rapid and sensitive optical method for various biological materials such as cells, biomolecules, and viruses by monitoring the dielectric permittivity changes at the interface of a transducer substrate and the analyte. This work focuses on exploring photonic crystal biosensor efficiency and sensitivity for viral load measurement. Photonic crystal biosensors are a unique class of biosensors that allow for label free analysis as they can control and confine light propagation due to the photonic bandgap. Silane treated photonic crystal was functionalized with anti-HIV-gp120 antibody before the addition of various concentrations of HIV pseudovirus. The samples were analyzed on a custom build transmission spectroscopy that used white light as a light source. The results showed a red shift at different virus concentrations, which demonstrates that photonic crystal biosensors are sensitive enough to detect differences in virus concentrations. Therefore, photonic crystals have a potential in the development of photonic crystal-based biosensors for viral load detection.

In stressful situations, concentrations of various molecules in the human body shift in response to the stressor. These molecules are measurable indicators of stress and are therefore called stress biomarkers. In many stress conditions, such as in overtraining syndrome, early detection of these biomarkers is highly important as the conditions are often not fully reversible. Early detection of the stress symptoms could be achieved with wearable sensors that would continuously monitor health information from different body fluids, such as sweat, urine, saliva, tears and blood. Compared to more conventional electrochemical or optical methods, plasmonic sensing could offer higher sensitivity, better stability and faster data collection while enabling implementation to compact devices. In this work, a sensor chip, based on grating-coupled surface plasmon resonance, is proposed for stress biomarker detection. In this work, we show a highly sensitive grating-based SPR sensor working in concert with a tunable laser within the wavelength range of 1528-1565 nm. The SPR sensor was designed using COMSOL Multiphysics software and was fabricated by means of UV nanoimprinting lithography. The implemented SPR sensor shows sensitivity close to 1200 nm/RIU, with a figure of merit (a ratio between the sensitivity and the full width at half maximum of the SPR dip) exceeding 400. The experimental results are strongly in agreement with COMSOL simulations. Such impressive characteristics of the fabricated sensor are among the best reported in the literature. The sensitivity of the chip was tested with two different stress-related biomarkers: glucose and lactate. With the tested range of 0 to 1.1 M, in the current version of the setup, without a receptor layer, the detection limits of glucose and lactate were 5.9 and 36.9 mM, respectively, which are close to the physiological ranges of these analytes in body fluids. The detection limit can be further improved with the sensor functionalization, thermal stabilization and mechanical isolation. When integrated into a wearable device, this approach has a potential in future healthcare applications, such as in continuous stress monitoring.

This research aims to identify the presence of early-stage cancer in individual living cells through the utilization of a surface plasmon resonance (SPR) prism-based biosensor device. The proposed investigation employs SPR phenomena to differentiate between healthy and cancerous cells, employing a multilayer sensing structure. A BK7 glass prism is used as the sensing platform, coated with a nanocomposite layer consisting of gold (Au), titanium dioxide (TiO₂), and graphene. The refractive index (RI) range of cancerous adrenal gland (PC12) cells is found to be between 1.381 and 1.395. The numerical results demonstrate that the proposed biosensor, equipped with single and multilayer nanocomposite structures, exhibits high sensitivity, figure of merit (FoM), detection accuracy (DA), and signal-to-noise ratio (SNR) for both healthy and cancerous PC12 cells. As the concentration of cancerous PC12 biomolecules increases in healthy cells, the SPR angle shifts, indicating variations in the refractive index due to the presence of cancerous cell biomolecules. The measurement of refractive index modifications in cancerous PC12 cells of the adrenal gland is achieved through an angle interrogation approach. Various thicknesses of TiO₂, Au, and graphene layers have been improved to enhance the performance of the biosensor.

We present a novel approach, interferometric phase intensity nanoscopy, to clearly define nanometer-scale objects situated closely together, going beyond the traditional diffraction limits. Our approach capitalizes on the strengths of interferometric scattering, which we've found remarkably effective for detecting entities as minute as individual nanoparticles and proteins. We integrated multiphase analysis with enhanced sensitivity to reveal elliptical Airy patterns that directly correlate with the nanostructures we observe. A key aspect of our methodology is the use of circular polarized illumination, which is essential for differentiating nanometer-scale objects that are closely spaced and below the diffraction limit. This technique opens up new possibilities for prolonged observation of nanoscale dynamics in biology, biomedicine, and bioengineering.

CRISPR-Cas9 is significantly potential and versatile gene-editing treatment for neurodegenerative disorders. The CRISPR-Cas9 system incorporates a single guide RNA (sgRNA) and Cas9 nuclease, which helps system to bind to the target sequence, and makes a double-strand break respectively. Viral vectors, as traditional delivery system of CRISPRCas9, cause safety issue regrading immunogenic complications. In this work we present alternative non-viral vectors with plasmonic properties as a delivery system. Our work provides a new perspective of nanoparticles for delivery and visualization applications of the CRISPR-Cas9 system.

Nanospeckle Illumination Microscopy (NanoSIM) utilizes plasmonic nanoisland structures to enable super-resolution surface imaging of live cells. By analyzing the intensity fluctuations of plasmonic nanospeckles, we achieved three-fold improved spatial resolution and the ability to identify multiple cellular structures. Experimental results demonstrate the potential of NanoSIM as an effective and versatile tool for investigating dynamic cellular processes within live cell membranes of HeLa cells, providing crucial insights into complex cellular interactions.

Phase intensity nanoscope (PINE) is a new super-resolution method to further improve the resolution of existing techniques. PINE utilizes an integrated phase-intensity device to modulate phase differences between electric field components to distinguish nanoprobes within a diffraction-limited region. This phase-intensity separation enables continuous imaging without photobleaching. PINE achieved sub-10nm resolution of cellular structures through precise localization of populations of randomly distributed nanorod probes. The distribution of localized nanorods forms patterns of underlying structures. By defining features from probe distribution patterns and minimizing the distances of each probe to its feature projection, PINE extracts sub-10nm structural information. PINE will pave the way for new sub-10nm long-term investigations of previously unexplored material, chemical and biological dynamics.

Surface plasmon resonance is a label free optical detection technique, which responds to refractive index variations that are induced by molecular binding incidents or binding affinities. This occurrence takes place when electrons on a thin metal film are excited by the light directed at an incident angle and travel parallel to the film. The angle of incidence that triggers surface plasmon resonance is linked to the refractive index of the material and even an insignificant change in the refractive index will be detected due to the sensitivity of the method. Because of its sensitivity, this technique is used as a real-time analytical approach that can be used for many different applications such as investigating the antibody-antigen affinity. In this study, surface plasmon resonance and localized surface plasmon resonance were investigated for their efficiency in detecting human immunodeficiency virus concentrations. This was achieved by functionalizing gold coated slides using an antibody against the surface protein of the human immunodeficiency virus. To the functionalized gold coated surface, different viral concentrations were added. The samples were then analyzed on home-built surface plasmon resonance and localized surface plasmon resonance biosensing systems. The results showed that the systems detected differences in viral concentrations as demonstrated by resonance curve shifts and varying transmission intensities. These findings will used towards the development of an optical biosensor to be used at point of care system for the detection of viral load in resource limited settings.

The study used a photon scanning tunneling microscope (PSTM) to obtain topographic and near-field images of dielectric surface features. Silica nanoprobes with an apex less than λ/10 were utilized. Light was directed through a prism to the metal-dielectric interface in total internal reflection (TIR) mode, with an adjustable incident angle and controlled polarization. Resonantly absorbed optical images of surface features were observed in the near-field, as well as interference patterns of surface plasmon waves at the plasmon resonance angle. Above the plasmon resonance, the optical images of surface features became inverted, indicating an off-resonance condition of the surface plasmons on the metal surface. The study found that the relative percent reflectivity (%ΔR) in the surface plasmon resonance imaging does not directly reflect the height of dielectric surface features, which mimic bio-materials on a sensor’s surface. There is always a distinctive region in which the height is proportional to the relative percent reflectivity