This PDF file contains the front matter associated with SPIE Proceedings Volume 11879, including the Title Page, Copyright information, and Table of Contents.

Structural imaging using light microscopy is a cornerstone of histology and cytology. However, the utility of the optical microscope for diagnostic imaging is limited by the fundamental tradeoff between the field of view and spatial resolution and a reliance on exogenous dyes to generate sufficient image contrast. Fourier Ptychographic Microscopy (FPM) is a complex imaging modality with the potential to overcome these limitations by recovering high-resolution images of sample amplitude and phase from a set of low-resolution raw images captured under inclined illumination. In this article we explore the application of FPM to clinical imaging using a simple, low-cost FPM system and simulated and experimental data to explore the influence of both image acquisition parameters and hardware configuration on image quality and imaging throughput. The practical performance of the method is investigated by imaging peripheral blood films and histological tissue sections. We find that, at the cost of increased computational complexity, FPM increases the information capture capacity of the optical microscope significantly, allowing label-free examination and quantification of features such as tissue and cell morphology over large sample areas.

Multiphoton imaging methods such as Coherent Raman Scattering (CRS) microscopy which also comprises Second Harmonic Generation (SHG) and Two Photon Excited Auto-Fluorescence (TPEAF) imaging (termed as multimodal Coherent Raman microscopy), have greatly facilitated the advancement of biomedical research due to their unique features. Multimodal CRS microscopy, is label free, chemically specific, inherently ‘confocal’ offering three independent contrast mechanisms which can be associated in a composite image comprising a wide range of chemical and structural information about the interrogated sample. The standard light source for multimodal CRS microscopy is a picosecond pumped Optical Parametric Oscillator (OPO) which has exhibited excellent performance but due to its associated high cost, maintenance, complexity and requirement of a dedicated optics laboratory, has hindered the wider adoption of multimodal CRS microscopy and especially its deployment in clinical applications. Here we present a novel, low cost Optical Parametric Amplifier (OPA) based on a MgO doped Periodically Poled Lithium Niobate (PPLN) crystal seeded by a continuous wave (CW) laser source and pumped by a picosecond laser at 1031nm, which removes any synchronisation requirements. We show that this OPA is a versatile light source module that can be tailored to the tunability and affordability requirements of the specific application. We demonstrate that it can be used either in association with an OPO or on its own as a light source for multimodal CRS microscopy and we show its performance by imaging a variety of standards and biological samples.

Here we describe the evaluation and subsequent re-design of an optical, point of care parasite infection diagnostic instrument. The original optical system was resolution limited by the focusing objective which had an f5.6 numerical aperture with an effective 3Mega pixel performance giving a minimum resolution of 3.73μm. Changing the objective to an f2.4 lens and employing 12Mega pixel sensor, combined with illumination modelling and re-design, improved resolution to 1.46μm within the necessary 3mm field of view. This presents a simple case for change which leads to benefits in both instrument sensitivity and improved parasite identification and speciation.

We are exploring the use of different optical regions in the Mid-infrared (Mid-IR) that can be used to develop future point of care tools and methodologies. This research will allow us to establish new methods to monitor proxies for health within blood samples. Mid-IR spectra of heme groups were studied by FTIR analysis to find spectral signatures can be exploited to quantify the redox state of haemoglobin as a function of its concentration. We performed Attenuated Total Reflection Spectroscopy (ATR) using heme groups. We found spectral differences between HbMet and Hb/HbO₂ in the regions 3000-3600, 2000-2100 and 1300 cm^-1. Mid-IR has the potential to expand the optical tools in medical monitoring and diagnosis for future non-invasive characterization systems. This could open a window of opportunity to understand proxies for disease and health in blood.

A recent effort in advancing a well established technique in material science - Brillouin spectroscopy - is making it amenable to applications in biomedical science, e.g. to live cells and tissues. Brillouin scattering is the inelastic scattering of light from longitudinal acoustic phonons that propagate across matter, sensing its viscoelastic properties. As the technique is performed in the GHz range (and on a micro-scale), much attention has been focused on the biological relevance of elasticity and viscosity probed in this spatio-temporal regime. In this talk, I review the most recent advances in this emerging biophotonic technique and its potential in biomechanics and mechanobiology.

Near-infrared spectroscopy (NIRS) is an optical technique that can measure brain tissue oxygenation and haemodynamics in real time and at the patient bedside allowing medical doctors to access important physiological information. In particular, time-domain NIRS (or TD-NIRS) is the most advanced NIRS technique, collecting the biggest amount of information, increasing the accuracy of the measurements and enabling to extract detailed information of the absolute optical properties of the tissues. All these optical information allows to extract detailed physiological information about the brain, and also get some insights into to the tissue’s anatomy. After presenting the basics of TDNIRS, typical applications of TD-NIRS in a clinical context will be presented.

All-optical ultrasound imaging, in which ultrasound is generated and received using light, is well-suited to minimally invasive surgical procedures. Here we present a device that can provide real-time M-mode ultrasound images, and demonstrate its use imaging a dynamic heart valve phantom. This device, comprising two optical fibres, one with a graphene-polydimethylsiloxane composite coating for ultrasound generation, and a second with a concave Fabry-Perot cavity for ultrasound reception, had a diameter of < 1 mm. This provided a wide ultrasound transmission bandwidth (> 30 MHz) that enabled imaging with high axial resolution (< 50 μm) and large imaging depths (> 2 cm). M-mode imaging with an A-line rate of 100 Hz was demonstrated on a heart valve phantom with realistic mitral valve motion. This work demonstrates the potential for all-optical ultrasound imaging to be used for guidance of intracardiac interventions.

Open-source technologies and solutions have paved the way for making science accessible the world over. Motivated to contribute to the direction of open-source methods, our current research presents a complete workflow of building a microscope using 3D printing and easily accessible optical components to collect images of biological samples. Further, these images are classified using machine learning algorithms to illustrate both the effectiveness of this method and show the disadvantages of classifying images that are visually similar. The second outcome of this research is an openly accessible dataset of the images collected, OPEN-BIOset, and made available to the machine learning community for future research. The research adopts the OpenFlexure Delta Stage microscope (https://openflexure.org/) that allows motorised control and maximum stability of the samples when imaging. A Raspberry Pi camera is used for imaging the samples in a transmission-based illumination setup. The imaging data collected is catalogued and organised for classification using TensorFlow. Using visual interpretation, we have created subsets from amongst the samples to experiment for the best classification results. We found that by removing similar samples, the categorical accuracy achieved was 99.9% and 99.59% for the training and testing sets. Our research shows evidence of the efficacy of open source tools and methods. Future approaches will use improved resolution images for classification and other modalities of microscopy will be realised based on the OpenFlexure microscope.

In this paper a nanostructure for DNA detection was proposed. The aim of the work is a theoretical analysis of the construction. The optimal dimensions of the nanostructure were determined. The characteristics of the model were obtained. It was revealed that the resonant wavelength changes by more than 100 nm, which can be detected even without using any instruments.