How to automate a kinematic mount using a 3D printed Arduino-based system

We demonstrate a simple, flexible and cost-effective system to automatize most of the kinematic mounts available nowadays on the market. It combines 3D printed components, an Arduino board, stepper motors, and simple electronics. The system developed can control independently and simultaneously up to ten stepper motors using commands sent through the serial port, and it is suitable for applications where optical realignment using flat mirrors is required on a periodic basis.Comment: 9 pages, 8 figure

Optical-Resolution Photoacoustic Microscopy

Optical microscopy, providing valuable biomedical insights at the cellular and organelle levels, has been widely recognized as an enabling technology. Mainstream optical microscopy technologies, including single-/multi-photon fluorescence microscopy and OCT, have demonstrated extraordinary sensitivities to fluorescence and optical scattering contrasts, respectively. However, the optical absorption contrast of biological tissues, which encodes essential physiological/pathological information, has not yet been fully assessable. The emergence of biomedical photoacoustics has led to a new branch of optical microscopy--OR-PAM. As a valuable complement to existing optical microscopy technologies, OR-PAM detects optical absorption contrasts with exquisite sensitivity: i.e., 100%). Combining OR-PAM with fluorescence microscopy or optical-scattering-based OCT: or both) provides comprehensive optical properties of biological tissues. Moreover, OR-PAM encodes optical absorption into acoustic waves, in contrast to the pure optical processes in fluorescence microscopy and OCT, and thus provides background-free detection. The acoustic detection in OR-PAM mitigates the impacts of optical scattering on signal degradation and naturally eliminates possible interferences: i.e., crosstalks) between excitation and detection, which is a common problem in fluorescence microscopy due to the overlap between the excitation and fluorescence spectra and imperfect extinction of the filter. Unique for high-resolution imaging of optical absorption, OR-PAM has demonstrated broad biomedical applications in fields such as neurology, ophthalmology, vascular biology, and dermatology. My doctoral research focuses on developments and biomedical applications of OR-PAM. The first part of my dissertation discusses the development of three generations of OR-PAM towards high-resolution, high-sensitivity, high-speed, and wide FOV in vivo imaging. In this section, I provide a comprehensive description of OR-PAM, including the principle, system design, system configuration, experimental procedures, laser safety, functional imaging scheme, and example biomedical applications at a variety of in vivo anatomical sites: i.e., skins, eyes and brains). The second part of my dissertation focuses on the application of OR-PAM in vascular biology, with an emphasis on neovascularization. In this section, I demonstrate longitudinal OR-PAM monitoring of the morphological: i.e., vessel diameter, length, tortuosity and volume) and functional: i.e., sO2) changes of angiogenic microenvironment at the capillary level, in both a non-disease TetON-HIF-1 transgenic mouse model and a cancer xenograft model in mouse ear. The last part of my dissertation focuses on the application of OR-PAM in neurology, with an emphasis on cortical stimulation, Alzheimer\u27s disease, and ischemic stroke. In this section, I use label-free OR-PAM for both acute monitoring of microvascular responses to direct electrical stimulations of the mouse somatosensory cortex through a cranial opening and longitudinal monitoring of the morphological and functional changes of cortical vasculature in a transient middle cerebral artery occlusion mouse model. I also explore the potential of OR-PAM for transcranial monitoring of amyloid plaque growth in an AD mouse model

Disposable cartridge based platform for real-time detection of single viruses in solution

Label-free imaging of viruses and nanoparticles directly in complex solutions is important for virology, vaccine research, and rapid diagnostics. These fields would all benefit from tools that allow for more rapid and sensitive characterization of viruses. Traditionally, light microscopy has been used in laboratories for detection of parasites, fungi, and bacteria for both research and clinical diagnosis because it is portable and simple to use. However, virus particles typically cannot be explored using light microscopy without the use of secondary labels due to their small size and low contrast. Characterization and detection of virus particles therefore rely on more complex approaches such as electron microscopy, ELISA, or plaque assay. These approaches require a significant level of expertise, purification of the virus from its natural environment, and often offer indirect verification of the virus presence. A successful virus visualization technique should be rapid, sensitive, and inexpensive, while needing minimal sample preparation or user expertise. We have developed a disposable cartridge based platform for real-time, sensitive, and label free visualization of viruses and nanoparticles directly in complex solutions such as serum. To create this platform we combined an interference reflectance imaging technique (SP-IRIS) with a sealable microfluidic cartridge. Through empirical testing and numeric modelling, the cartridge parameters were optimized and a flow rate of ~3 µL/min was established as optimal. A complex 2-dimensional paper based capillary pump was incorporated into the polymer cartridge to achieve a constant flow rate. Using this platform we were able to reliably show virus detection in a 20 minute experiment. We demonstrate sensitivity comparable to laboratory-based assays such as ELISA and plaque assay, and equal or better sensitivity compared to paper based rapid diagnostic tests. These results display a platform technology that is capable of rapid multiplexed detection and visualization of viruses and nanoparticles directly in solution. This disposable cartridge based platform represents a new approach for sample-to-answer label-free detection and visualization of viruses and nanoparticles. This technology has the potential to enable rapid and high-throughput investigation of virus particle morphology, as well as be used as a rapid point-of-care diagnostic tool where imaging viruses directly in biological samples would be valuable

Technological Advances in the Diagnosis and Management of Pigmented Fundus Tumours

Choroidal naevi are the most common intraocular tumour. They can be pigmented or non-pigmented and have a predilection for the posterior uvea. The majority remain undetected and cause no harm but are increasingly found on routine community optometry examinations. Rarely does a naevus demonstrate growth or the onset of suspicious features to fulfil the criteria for a malignant melanoma. Because of this very small risk, optometrists commonly refer these patients to hospital eye units for a second opinion, triggering specialist examination and investigation, causing significant anxiety to patients and stretching medical resources. This PhD thesis introduces the MOLES acronym and scoring system that has been devised to categorise the risk of malignancy in choroidal melanocytic tumours according to Mushroom tumour shape, Orange pigment, Large tumour size, Enlarging tumour and Subretinal fluid. This is a simplified system that can be used without sophisticated imaging, and hence its main utility lies in the screening of patients with choroidal pigmented lesions in the community and general ophthalmology clinics. Under this system, lesions were categorised by a scoring system as ‘common naevus’, ‘low-risk naevus’, ‘high-risk naevus’ and ‘probable melanoma.’ According to the sum total of the scores, the MOLES system correlates well with ocular oncologists’ final diagnosis. The PhD thesis also describes a model of managing such lesions in a virtual pathway, showing that images of choroidal naevi evaluated remotely using a decision-making algorithm by masked non-medical graders or masked ophthalmologists is safe. This work prospectively validates a virtual naevus clinic model focusing on patient safety as the primary consideration. The idea of a virtual naevus clinic as a fast, one-stop, streamlined and comprehensive service is attractive for patients and healthcare systems, including an optimised patient experience with reduced delays and inconvenience from repeated visits. A safe, standardised model ensures homogeneous management of cases, appropriate and prompt return of care closer to home to community-based optometrists. This research work and strategies, such as the MOLES scoring system for triage, could empower community-based providers to deliver management of benign choroidal naevi without referral to specialist units. Based on the positive outcome of this prospective study and the MOLES studies, a ‘Virtual Naevus Clinic’ has been designed and adapted at Moorfields Eye Hospital (MEH) to prove its feasibility as a response to the COVID-19 pandemic, and with the purpose of reducing in-hospital patient journey times and increasing the capacity of the naevus clinics, while providing safe and efficient clinical care for patients. This PhD chapter describes the design, pathways, and operating procedures for the digitally enabled naevus clinics in Moorfields Eye Hospital, including what this service provides and how it will be delivered and supported. The author will share the current experience and future plan. Finally, the PhD thesis will cover a chapter that discusses the potential role of artificial intelligence (AI) in differentiating benign choroidal naevus from choroidal melanoma. The published clinical and imaging risk factors for malignant transformation of choroidal naevus will be reviewed in the context of how AI applied to existing ophthalmic imaging systems might be able to determine features on medical images in an automated way. The thesis will include current knowledge to date and describe potential benefits, limitations and key issues that could arise with this technology in the ophthalmic field. Regulatory concerns will be addressed with possible solutions on how AI could be implemented in clinical practice and embedded into existing imaging technology with the potential to improve patient care and the diagnostic process. The PhD will also explore the feasibility of developed automated deep learning models and investigate the performance of these models in diagnosing choroidal naevomelanocytic lesions based on medical imaging, including colour fundus and autofluorescence fundus photographs. This research aimed to determine the sensitivity and specificity of an automated deep learning algorithm used for binary classification to differentiate choroidal melanomas from choroidal naevi and prove that a differentiation concept utilising a machine learning algorithm is feasible

Surgical Ophthalmic Oncology

Designed as an easy-to-use, practical guide to tumors of the eye, lids, and orbit, this Open Access book comprehensively addresses surgical treatment and management of diseases related to ophthalmic oncology. Surgical Ophthalmic Oncology: A Collaborative Open Access Reference is an ideal reference for general ophthalmologists, surgeons, fellows and trainees around the world who encounter these diseases in the care of their patients. Notably, this book includes considerations for those ophthalmologists offering subspecialty care in environments with limited access to advanced technology and instrumentation. Individual chapters address diagnostic indications, pre-operative and post-operative concerns, and provide detailed explanations of surgical techniques required to manage various eye cancer ailments with help of ample illustrations. High-quality videos included throughout the book provide readers with the opportunity to review surgical steps in real-time as a learning tool. Chapters thoroughly cover tumors of eyelid, cornea and conjunctiva, orbit as well as intraocular tumors, while later chapters discuss ophthalmic radiation therapy. The book concludes with a section on ophthalmic pathology which details essential guidelines on relevant aspects from specimen collection and transport, to interpretation of the pathology report. Surgical Ophthalmic Oncology: A Collaborative Open Access Reference is a unique and necessary valuable resource for ophthalmologists, trainees, and related medical professionals working in underserved areas in providing quality care for patients suffering from ocular cancers. ; Open Access text that discusses Preferred Practice Guidelines for common surgeries performed on tumors of the eye and adnexa Written for general ophthalmologists providing oncology care and specialists practicing in areas with limited access to advanced technology and instrumentation Includes chapters on eyelid tumors, conjunctival and corneal tumors, intraocular tumors, brachytherapy, and ocular pathology Each chapter includes extensive color pictures and relevant video to assist the clinician in the various surgical procedures discusse

New Insights on Biofilm Antimicrobial Strategies

Over the last few decades, the study of microbial biofilms has been gaining interest among the scientific community. These microbial communities comprise cells adhered to surfaces that are surrounded by a self-produced exopolymeric matrix that protects biofilm cells against different external stresses. Biofilms can have a negative impact on different sectors within society, namely in agriculture, food industries, and veterinary and human health. As a consequence of their metabolic state and matrix protection, biofilm cells are very difficult to tackle with antibiotics or chemical disinfectants. Due to this problem, recent advances in the development of antibiotic alternatives or complementary strategies to prevent or control biofilms have been reported. This book includes different strategies to prevent biofilm formation or to control biofilm development and includes full research articles, reviews, a communication, and a perspective