Evaluating sensitivity and specificity of the Biomeme Franklin™ three9 real-time PCR device and SARS-CoV-2 go-strips assay using clinical samples.

We evaluated the sensitivity and specificity of the Biomeme Franklin™ three9 Real-Time PCR Thermocycler and Biomeme SARS-CoV-2 Go-Strips in the detection of SARS-CoV-2. The Biomeme Franklin™ three9 platform is a portable, battery-operated system that could be used in remote settings. We assessed performance of the Biomeme SARS-CoV-2 detection system at a wide range of viral concentrations, examined cross-reactivity of the SARS-CoV-2 Go-Strips against several near-neighbor respiratory pathogens, and evaluated agreement against the BioFire® Respiratory Panel 2.1 in four clinical sample types. Our data indicate the Biomeme Go-Strips can reliably detect SARS-CoV-2 at a concentration of 4.2 × 103 copies/mL. No cross reactivity of the Go-Strips targets was detected against any of the tested near-neighbor respiratory pathogens. Cohen's kappa statistics ranged from 0.68 to 0.92 between results from the Biomeme SARS-CoV-2 Go-Strips and the BioFire® Respiratory Panel 2.1 in all the different sample types. Compared to the BioFire® Respiratory Panel 2.1, the Biomeme SARS-CoV-2 Go-Strips demonstrated statistically significantly lower sensitivity in 3 out of 5 sample types. Overall, our study demonstrates the Biomeme Franklin™ three9 used with the SARS-CoV-2 Go-Strips is an effective system for the detection of SARS-CoV-2 that could potentially be used in a remote or austere environment.

Assessment of Commercial Off-the-Shelf Tissue Adhesives for Sealing Military-Relevant Corneal Perforation Injuries.

INTRODUCTION: Open-globe ocular injuries have increased in frequency in recent combat operations due to increased use of explosive weaponry. Unfortunately, open-globe injuries have one of the worst visual outcomes for the injured warfighter, often resulting in permanent loss of vision. To improve visual recovery, injuries need to be stabilized quickly following trauma, in order to restore intraocular pressure and create a watertight seal. Here, we assess four off-the-shelf (OTS), commercially available tissue adhesives for their ability to seal military-relevant corneal perforation injuries (CPIs). MATERIALS AND METHODS: Adhesives were assessed using an anterior segment inflation platform and a previously developed high-speed benchtop corneal puncture model, to create injuries in porcine eyes. After injury, adhesives were applied and injury stabilization was assessed by measuring outflow rate, ocular compliance, and burst pressure, followed by histological analysis. RESULTS: Tegaderm dressings and Dermabond skin adhesive most successfully sealed injuries in preliminary testing. Across a range of injury sizes and shapes, Tegaderm performed well in smaller injury sizes, less than 2 mm in diameter, but inadequately sealed large or complex injuries. Dermabond created a watertight seal capable of maintaining ocular tissue at physiological intraocular pressure for almost all injury shapes and sizes. However, application of the adhesive was inconsistent. Histologically, after removal of the Dermabond skin adhesive, the corneal epithelium was removed and oftentimes the epithelium surface penetrated into the wound and was adhered to inner stromal tissue. CONCLUSIONS: Dermabond can stabilize a wide range of CPIs; however, application is variable, which may adversely impact the corneal tissue. Without addressing these limitations, no OTS adhesive tested herein can be directly translated to CPIs. This highlights the need for development of a biomaterial product to stabilize these injuries without causing ocular damage upon removal, thus improving the poor vision prognosis for the injured warfighter.

Transcorneal Freezing in Aged Rabbits as a Platform for Evaluating Corneal Endothelial Cell Therapeutics.

PURPOSE: Transcorneal freezing is a common technique used in rabbits to induce damage to the corneal endothelium. Previous studies have been performed with a range of freezing temperatures, times, and rabbit ages. Here, we aimed to characterize the aged rabbit endothelium after transcorneal freezing to establish an innate corneal endothelial cell regrowth rate and propose it as a mechanism for evaluation of therapeutic efficacy in rabbit models. METHODS: Central corneas of anesthetized New Zealand White rabbits (n=3) aged 18-24 months were exposed to nitrous oxide cooled probes for 30 seconds. Animals were assessed by in vivo confocal microscopy, applanation tonometry, specular microscopy, optical coherence tomography, and histology. The contralateral eye acted as a control. Images were taken immediately before and after injury and on days 2, 4, 7, 11, and 14. RESULTS: Following transcorneal freezing, there was a significant decrease in corneal endothelium density and a temporary increase in corneal thickness. Endothelial density decreased by 95% immediately after injury compared to controls and showed linear recovery over 14 days, reaching a 38% reduction by day 14. There was a significant increase in pleomorphism across all time points post-injury. Conversely, corneal thickness increased two days post injury but recovered at all later time points. Intraocular pressure was not affected throughout. CONCLUSIONS: This corneal endothelium injury platform is ideal for injury and therapeutic research as it can be rapidly performed, and has minimal impact on corneal thickness and intraocular pressure. Due to innate rabbit endothelial regrowth, it is vital to establish corneal endothelial recovery rate before evaluating therapeutics for efficacy in this model system.

Amniotic membrane allografts maintain key biological properties post SCCO2 and lyophilization processing.

Amniotic membrane (AM) has been shown to enhance corneal wound healing due to the abundance of growth factors, cytokines, and extracellular matrix (ECM) proteins inherent to the tissue. As such, AM has garnered widespread clinical utility as a biological dressing for a number of ophthalmic and soft tissue applications. The preparation, sterilization, and storage procedures used to manufacture AM grafts are extremely important for the conservation of inherent biological components within the membrane. Current processing techniques use harsh chemicals and sterilization agents that can compromise the fundamental wound healing properties of AM. Furthermore, commercially available cryopreserved AM products require specific storage conditions (e.g., ultra-low freezers) thereby limiting their clinical availability in austere environments. Supercritical carbon dioxide (SCCO2) technology allows for the sterilization of biological tissues without the resulting degradation of integral ECM proteins and other factors often seen with current tissue sterilization processes. With this study we demonstrate that lyophilized AM, sterilized using SCCO2, maintains similar biochemical properties and biocompatibility as that of commercially available AM products requiring specialized cold storage conditions.

An Open-Globe Porcine Injury Platform for Assessing Therapeutics and Characterizing Biological Effects.

Open-globe injuries can result in permanent vision loss, partly due to extended delays between injury and medical intervention. Even with early intervention, the management of open-globe injuries remains a challenge for ophthalmologists, mostly due to inadequate or suboptimal current therapies. To aid in the development of novel therapeutics and track toxicological and pathophysiological changes, this article details an open-globe injury platform capable of inducing injuries in enucleated porcine eyes. The injury platform relies on a high-speed solenoid device to mimic explosive injury scenarios, allowing for large, complex injury shapes and sizes that are often observed in casualties and are more difficult to treat. The system can be implemented with precise computer control of the injury mechanism to allow for more complex setups. Also, the system can make use of real-time intraocular pressure measurement to track changes during injury induction and to assess therapeutic efficacy for restoring intraocular pressure and the integrity of the eye. These protocols will assist with implementation of the injury model in prospective laboratories seeking to develop therapeutics or studying biological changes that occur from this type of traumatic injury. Published 2020. U.S. Government. Basic Protocol 1: Preparing gelatin molds and porcine eye tissue Basic Protocol 2: Creating an open-globe injury using a solenoid device Alternate Protocol 1: Constructing a computer-controlled system for open-globe injury Alternate Protocol 2: Constructing a pressure measurement system for tracking intraocular pressure Support Protocol 1: Assessing ocular compliance in porcine eyes Support Protocol 2: Assessing outflow rate from the anterior chamber Support Protocol 3: Assessing burst pressure in porcine eyes.

Development and Characterization of a Benchtop Corneal Puncture Injury Model.

During recent military operations, eye-related injuries have risen in frequency due to increased use of explosive weaponry which often result in corneal puncture injuries. These have one of the poorest visual outcomes for wounded soldiers, often resulting in blindness due to the large variations in injury shape, size, and severity. As a result, improved therapeutics are needed which can stabilize the injury site and promote wound healing. Unfortunately, current corneal puncture injury models are not capable of producing irregularly shaped, large, high-speed injuries as seen on the battlefield, making relevant therapeutic development challenging. Here, we present a benchtop corneal puncture injury model for use with enucleated eyes that utilizes a high-speed solenoid device suitable for creating military-relevant injuries. We first established system baselines and ocular performance metrics, standardizing the different aspects of the benchtop model to ensure consistent results and properly account for tissue variability. The benchtop model was evaluated with corneal puncture injury objects up to 4.2 mm in diameter which generated intraocular pressure levels exceeding 1500 mmHg. Overall, the created benchtop model provides an initial platform for better characterizing corneal puncture injuries as seen in a military relevant clinical setting and a realistic approach for assessing potential therapeutics.

Treatment of corneal chemical alkali burns with a crosslinked thiolated hyaluronic acid film.

PURPOSE: The study objective was to test the utilization of a crosslinked, thiolated hyaluronic acid (CMHA-S) film for treating corneal chemical burns. METHODS: Burns 5.5mm in diameter were created on 10 anesthetized, male New Zealand white rabbits by placing a 1N NaOH soaked circular filter paper onto the cornea for 30s. Wounds were immediately rinsed with balanced salt solution (BSS). CMHA-S films were placed in the left inferior fornix of five injured and five uninjured animals. Five animals received no treatment. At 0h, 48h, 96h, and on day 14 post chemical burn creation, eyes were evaluated by white light imaging, fluorescein staining, and optical coherence tomography (OCT). Corneal histology was performed using H&E and Masson's Trichrome stains. RESULTS: Image analysis indicated biocompatible CMHA-S treatment resulted in significant decreases in the areas of corneal opacity at 48h, 96h, and on day 14 postoperatively. A significant increase in re-epithelialization was seen 14days post injury. CMHA-S treated corneas showed significantly less edema than untreated burns. No pathological differences were observed in corneal histological samples as a result of CMHA-S treatment. CONCLUSIONS: CMHA-S films facilitate re-epithelialization and decrease the area of corneal opacity in our corneal alkali burn rabbit model.

Magnetic Nanoparticles as a Potential Vehicle for Corneal Endothelium Repair.

The corneal endothelium is paramount to the health and function of the cornea as damage to this cell layer can lead to corneal edema, opacification, and ultimately vision loss. Transplantation of the corneal endothelium is associated with numerous limitations, including graft rejection, thus an alternative therapeutic treatment is needed to restore endothelial layer integrity. We hypothesize that a nanotechnology-based approach using superparamagnetic iron oxide nanoparticles (SPIONPs) can ultimately be used to guide corneal endothelial cells (CECs) to injured areas via an external magnetic force without changing their morphology or viability. In this feasibility study we examined the effects of SPIONPs on the morphology and viability of bovine CECs in the presence of a magnetic force. The CECs were exposed to increasing SPIONP concentrations and the viability and cytoskeletal structure assessed over 3 days via metabolic analysis and rhodamine phalloidin staining. Significant differences (p < .05) in the metabolic activity of the CECs (100 × 10(6) SPIONP/cell) occurred in the presence of magnetic force versus those with no magnetic force. No differences were observed in the cytoskeleton of CECs in the presence or absence of magnetic force for all SPIONP concentrations. These SPIONPs will next be evaluated with human CECs for future applications.