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  • Pulsed Infrared Neural Stimulation of Vestibular System Evokes Cardiovascular Responses

    Darrian Rice1, Weitao Jiang1, Giorgio P. Martinelli2, Gay R. Holstein2, and Suhrud M. Rajguru1 1Department of Biomedical Engineering, University of Miami, 2Department of Neurology, Icahn School of Medicine at Mount Sinai Cardiovascular adaptation is a complex behavior influenced by various brainstem inputs including those from the vestibulo-sympathetic reflex (VSR). The VSR responds quickly to maintain adequate blood flow to the brain during changes in head position and posture by increasing sympathetic flow and is thought to work alongside the well-known autonomic feedback system, the baroreflex. Previous studies have demonstrated cardiovascular responses to activation of the vestibular labyrinth or 8th nerve. However, the methods of stimulation are non-specific and cannot effectively highlight the contributions of individual endorgans, limiting development of effective vestibular therapy. We have developed a method of applied infrared neural stimulation (INS) to individual vestibular endorgans to better characterize the VSR. In the present study, we investigated changes in heart rate (HR) and blood pressure (BP) evoked by INS of the posterior canal in a rat.  Frequency modulated INS (1863nm, 200us, 250pps, varied radiant exposure and frequencies) was delivered to the posterior canal via optical fibers to the right inner ear. HR and BP were measured via a small animal single pressure implantable device (DSI pressure sensing technologies, HD-S10) inserted into the femoral artery prior to stimulation.  Sinusoidal INS at 0.05 Hz directed at the posterior canal induced oscillations in HR and BP. An initial deflection in both were observed followed by sinusoidal modulation and return to baseline in several rats. MicroCT image analysis highlighted the spatial selectivity of IR and showed the posterior canal ampullary region to be the primary target of stimulation. We hypothesize that activation of vertical canal receptors and neurons provide inputs to the vestibulo-sympathetic reflex upon changes in head position relative to gravity. Results are suggestive of selective activation of the vestibular system by pulsed infrared, which can be used to detail the functioning of the VSR pathways activated by individual end organs.

  • Tissue-Engineered Stromal Reticulum to Study The Role of Lymph Node Fibroblastic Reticular Cell Networks in Autoimmune Diabetes

    Freddy Gonzalez Badillo1,2, Shane Wright1,2, Nicholas DeAngelis1,2, Mackenzie Scully1,2, Alice A. Tomei1,2 1Diabetes Research Institute, 2Department of Biomedical Engineering – University of Miami The lymph node (LN) is a secondary lymphoid organ where immune reactions are orchestrated. Fibroblastic Reticular Cells (FRCs) are the main stromal component of the LN paracortex. Besides forming the LN scaffold, FRCs expand/contract the LN to accommodate for the proliferating T-cells during immune responses. FRCs also participate in tolerance maintenance, which is affected in Type 1 Diabetes (T1D). We have developed a physiologically relevant in-vitro model of the FRC stromal network that recapitulates the native LN. Using the FRC engineered reticulum we will determine whether FRC interactions with beta-cell autoreactive T-cells and FRC contractility is affected in T1D. Methods:  LNs were obtained from 4 and 12 week-old C57BL/6 (B6) mice and from age-matched non-obese diabetic (NOD) mice. LNs were fixed in formalin, paraffin embedded, sectioned and stained for alpha-smooth muscle actin, gp38 and DAPI. Commercially available collagen sponges (CS) and 2% collagen gels (CG) were compared as FRC scaffolds. 24 hours after FRC seeding, scaffolds were fixed in formalin and stained with Phalloidin and DAPI. Images of both native LN and engineered reticula were obtained with a Leica SP5 microscope and the reticulum pore size was quantified using ImageJ. FRC contractility was measured by quantifying the size of FRC-seeded 2% CG disks 48 hours after fabrication. Results: FRC reticula have smaller pore sizes in healthy B6 models (5.42 ± 1.99 µm) than NOD T1D models (7.03 ± 2.58 µm, p < 0.0001) at 12 weeks of age. Engineered reticula pore size is bigger (CS: 42.7 ± 16.3; CG: 22.6 ± 13.9) than the native reticulum. B6 mice FRCs contracted CGs more (40%) than age-matched NOD FRCs (10%). Future studies will utilize the 3D FRC engineered platform we developed to determine FRCs interaction with antigen-specific T-cells using antigens related to T1D and its correlation with contractile properties

  • Self-assembling Nanomaterials for Local Delivery of Immunomodulatory Drugs in Cell Transplantation

    Teresa De Toni1,2, Diana Velluto1, Alice A. Tomei1,2 1Diabetes Research Institute, 2Department of Biomedical Engineering – University of Miami Reducing inflammation associated with transplantation of pancreatic islets will likely enhance islet graft outcomes. Nanocarriers may improve drug delivery to the target site of immunomodulatory drugs enhancing their poor water solubility, stability and side effects. We prepared amphiphilic block copolymers-based nanomaterials made of poly(ethylene glycol)-poly(propylene sulfide) (PEG-PPS) and poly(ethylene glycol)-oligo(ethylene sulfide) (PEG-OES), which self-assemble in water forming micelles and nanofibers loading hydrophobic drugs without chemical conjugation. We evaluated and compared micelles and nanofibers as nanocarriers for dexamethasone (Dexa), beclomethasone dipropionate (BD), and loteprednol etabonate (LE), and cyclosporine A (CsA). Methods: PEG44-PPS20 and of PEG44-OES5 block copolymers were synthetized by anionic ring opening polymerization of propylene sulfide (PS) and ethylene sulfide (ES), respectively and characterized by 1HNMR. The cosolvent evaporation method was used to form micelles and nanofibers with and without drugs. The size of the nanocarriers was measured with dynamic light scattering (DLS) and drug loading was evaluated with a RP-HPLC method. We calculated the drug encapsulation efficiency (EE%), and the drug loading capacity (LC). The drug release from micelles and nanofibers was studied using dialysis and RP-HPLC. Toxicity was evaluated by the MTT assay on MIN6, and RAW 264.7 cells after incubation with different concentrations of drug-nanocarriers. Results: PEG44-PPS20 and PEG44-OES5 formed micelles of about 26nm in diameter and nanofibers of 92nm in length. These concentrations of micelles-drug and nanofiber-drug didn’t show any toxicity in vitro. The in vitro release of Dexa was sustained over 8h and 5h from micelles and nanofibers, respectively. BD was released in 24h from nanofibers and 10 days from micelles. Finally, the release of CsA was maintained over 7 days for nanofibers and over 14 days for micelles. These findings will address the current challenges of the anti-inflammatory therapy, which is critical for improving the outcomes of islet transplantation.

  • Localized Therapeutic Hypothermia Mitigates Noise-Induced Hearing Loss

    Samantha Rincon1, Rachele Sangaletti2, Ilmar Tamames1, Anne Feliciano1, Curtis King3 and Suhrud M. Rajguru1,2 1Department of Biomedical Engineering, 2Department of Otolaryngology, University of Miami, 3Lucent Medical Systems Noise-induced hearing loss (NIHL) is caused either by acute acoustic trauma or by repetitive exposure to loud sounds and remains one of the leading global occupational diseases, with nearly 30–40 million Americans exposed to hazardous noise levels on a regular basis. In the present study, we assessed the therapeutic benefit and mechanisms of localized therapeutic hypothermia in preservation of residual hearing and mitigation of cochlear injury following acoustic trauma in a rat model. Brown Norway rats were separated into two groups: (1) normothermic NIHL and (2) hypothermic-treated NIHL. Auditory brainstem response (ABR) and distortion product optoacoustic emission (DPAOE) were measured to quantify changes in hearing threshold in anesthetized rats (44 mg/kg ketamine, 5 mg/kg xylazine) prior to NIHL and at various time points following trauma. NIHL was delivered in anesthetized rats (isoflurane) during 2 hours of continuous noise exposure using a 4-8 kHz narrowband noise emitted from a speaker with intensities of 105 or 120dBSPL. Hypothermia was applied to cool the cochlea (~33ºC) for 2 hours. Following measurements at multiple time points over 30 days, cochleae were harvested for immunolabeling and cell counting. In a separate set of animals, cochleae were harvested at several timepoints after each treatment for labeling and counting hair cells and ribbon synapses. Previous studies have suggested that animals exposed to noise when hypothermic show significantly less elevation of hearing thresholds than those exposed when euthermic. Our preliminary results confirm that hypothermia treatment even post-NIHL preserves significant residual function. It is known that multiple mechanisms must be targeted to reduce acute and chronic inflammation, prevent cell death and loss of function following trauma to the inner ear. Hypothermia is known to reduce oxidative stress and increase activity of anti-apoptotic pathways, providing mechanisms whereby it might also reduce adverse effects of noise on hearing.

  • Generation of Corneal Microlayer Thickness Maps

    Amr Elsawy, Mohamed Abou Shousha, Mohamed Abdel-Mottaleb

    Electrical and Computer Engineering Dept, Ophthalmolgy Dept., Bascom Palmer Eye Institute, Electrical and Computer Engineering Dept

    Optical Coherence Tomography (OCT) is a technology that is convenient for imaging the eye because it is non-contact and no-invasive. High resolution images of the anterior and posterior segments of the eye can be obtained using OCT. The anterior segment involves the cornea and its microlayers. Measuring the thickness of different corneal microlayers, from OCT images, is important for diagnosing several corneal diseases such as Fuchs dystrophy, keratoconus and corneal graft rejection.  Segmentation of corneal microlayers is needed to be able to measure the thickness. However, manual segmentation of those microlayers in OCT images is subjective and time consuming. Therefore, automatic segmentation is a necessity. Many methods were proposed for segmentation of corneal microlayers on OCT images, but none of these methods segment all the microlayers and they are not robust. Moreover, there is no large annotated database of corneal OCT images which prevents the application of machine learning methods such as deep learning in the segmentation. We presented new corneal OCT image segmentation methods using polynomial fitting, Randomized Hough Transform (RHT) or graph search. Our proposed methods can segment up to six corneal microlayers. The proposed methods help to measure thickness of corneal microlayers to quantify the diseases associated with those layers. The proposed methods were validated against manual segmentation of a random sample of images. The manual segmentation is done by manual trained operators. The segmentation error between the automatic segmentation and the manual segmentation is comparable to the inter-operator error between the manual operators and the significance test shows that there is no significance between them. Then, the segmentation is carried out along the cuts of a radial scan to provide 3D surfaces of corneal microlayers. Then, the surfaces are corrected due to light refraction and the thickness maps of corneal microlayers are obtained by measuring the thickness between those surfaces.

  • Redesigned Bubble CPAP to Effectively Curtail Preterm Infant Mortality in Low Resource Areas

    Elikem K. Tettey-Tamaklo, Solomon Mensah

    Industrial Engineering

    Respiratory distress syndrome (RDS) is a lung disorder that affects the normal breathing of preterm infants by preventing their lungs from staying open leading to obstructed breathing. This disorder is responsible for much of the largely preventable preterm infant mortality in many developing countries.

    The solution to this disease would be to provide the preterm babies with a constant supply of oxygen until their lungs mature enough to stay open without help. Commercial respiratory assistants are very expensive and made for first world facilities, but are being used in third world hospitals. Their combination of high cost and complexity result in the inability of local hospitals to afford or maintain

    them when they break. The result is less of these devices available to cater to the growing infant mortality crisis within developing countries.

    In an attempt to curb the problem, a cost-effective and practical intervention would be necessary. This intervention comes in the form of a completely redesigned bCPAP. This device is a respiratory device that provides the ideal mixture of oxygen and air, delivered to the delicate lungs of the baby.

    Therapeutic Innovations redesigns medical devices towards third world countries by removing unnecessary complex features while still maintaining reliable functionality. Part of our solution is to use pre-fabricated parts from medical suppliers and assembling them in a novel modular fashion to create our bCPAP. This removes manufacturing and approval costs, and allow us to focus on designing our product towards the conditions of third world countries.

  • In Vivo Measurement of the Attenuation Coefficient of the Sclera and Ciliary Muscle from Transscleral Optical Coherence Tomography images

    Monterano Mesquita, Gabrielle1, 2; Chang, Yu-Cherng1, 2; Cabot, Florence1, 3; Ruggeri, Marco1; Yoo, Sonia H.3, 4; Parel, Jean-Marie A.1, 4; Manns, Fabrice1, 2 1Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States. 2Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, United States. 3Anne Bates Leach Eye Hospital, Bascom Palmer Eye Institute, University of Miami College of Engineering, Coral Gables, FL, United States. 4Brien Holden Vision Institute and Vision Cooperative Research Center, Sydney, NSW, Australia.  Images of accommodation-induced changes in the ciliary muscle acquired using Optical Coherence Tomography (OCT) can provide insight into the mechanism of accommodation. However, the inner boundary of the ciliary body near the apex is often difficult to visualize due to signal loss. The purpose of this study was to quantify the attenuation coefficients of the sclera and ciliary muscle in vivo to better understand the mechanism of signal loss in OCT images of the ciliary muscle.

  • Toward translating conformal polymer encapsulated islet transplantation as an autoimmune diabetes therapy

    Aaron A. Stock, Vita Manzoli, Diana Velluto, Felicia Pagliuca, Alice A. Tomei

    Biomedical Engineering

    Type 1 diabetes is an autoimmune disease characterized by T cell mediated destruction of the β cells of the islets of Langerhans in the pancreas. Pursuant to the loss of these insulin secreting cells, blood glucose cannot be regulated and those affected suffer reduced quality of life or even mortality. Islet transplantation presents a promising opportunity for curing this disease. However, this procedure is only indicated for adults with the most severe and unnoticed hypoglycemia due to the required systemic immunosuppression and limited availability of donor islets. Stem cell-derived insulin secreting cells (hereafter, scβ cell clusters) represent a potentially unlimited source of islets for transplant, and in combination with conformal encapsulation, may be the first immune-suppression free islet transplant platform that is indicated for the majority of people affected by autoimmune diabetes.

  • Engineering an In Vitro Human Glaucoma Model Using Atomic Force Microscopy-Based Nanolithography

    W.M. Batchelor1, Noel Ziebarth1, Vincent Moy2

    1Department of Biomedical Engineering, College of Engineering, University of Miami

    2Department of Cellular Physiology and Molecular Biophysics, Miller School of Medicine, University of Miami

    Glaucoma is a group of several related eye diseases that lead to progressive optic nerve degeneration and retinal ganglion cell (RGC) death. As of today, over 60 million people around the world suffer from some degree of permanent vision loss due to glaucoma, making glaucoma globally the most common cause of permanent visual impairment. Because of this, researchers and clinicians have focused on developing novel treatment strategies for glaucoma; however, many forms of glaucoma are difficult to treat and will eventually result in blindness. Glaucoma is a very complex disease, and animal models do not accurately capture all facets of its extremely complex pathogenesis. Lack of an appropriate glaucoma model slows development of a suitable treatment. An in vitro model of glaucoma, which better recapitulates the development of glaucoma in humans than traditional animal models, would be very useful in both studying the disease and creating treatments for it.

    This project proposes a novel in vitro model of human glaucoma that will incorporate both stem-cell derived retinal ganglion cells and unique biomaterials. For the first time, atomic force microscope (AFM) based methods of nanolithography will be used to chemically, physically, and topologically functionalize an electrospun collagen scaffold to form the base of the model. Over the course of this project, we will design and build a customized AFM for nanolithography on biomaterials, use this AFM to functionalize a biomaterial scaffold, combine cells to the scaffold to assemble the model, and finally, we will validate our model to determine how effective it is at simulating glaucoma.

  • Quantifying changes in eye shape during accommodation using Optical Coherence Tomography Images

    Siobhan Williams1,2, Giovanni Gregori3, Marco Ruggeri1,2, Yu-Cherng Chang1,2, Florence Cabot1,3, Arthur Ho1,2,4, Sonia Yoo1-3, Jean-Marie Parel1-4, Fabrice Manns1,2

    1Ophthalmic Biophysics Center, University of Miami Miller School of Medicine, FL; 

    2Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami, Coral Gables, FL; 

    3Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL; 

    4Vision Cooperative Research Centre, Sydney, Brien Holden Vision Institute, UNSW, Sydney, Australia

    Dynamic mechanisms of the eye’s accommodative apparatus are a key component in understanding presbyopia. A recently developed extended-depth spectral domain optical coherence tomography (SD-OCT) imaging system provides a non-invasive technique to stimulate accommodation and capture the eye’s response (Ruggeri et al. 2012). Large datasets generated by this approach require an automated and accurate method to quantify the eye shape using OCT images. This project introduces a fast, automated algorithm for quantifying dynamic changes of the crystalline lens during accommodation using two-dimensional OCT images. The algorithm attains a delicate balance between the inevitable trade-off between robustness and speed to efficiently process large volumes of data.

  • Combined Autorefractor and Visual Fixation Target to Study Human Accommodative Response: Benchtop Optical Design and Calibration

    Heather Durkee1,2, Channing Chang1,2, Gabrielle Monterano Mesquita1,2, Marco Ruggeri1, Jean-Marie Parel1,2, Fabrice Manns1,2 1Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine; 2Department of Biomedical Engineering, College of Engineering, University of Miami, Coral Gables, FL.

    • Accommodation is the process by which eye changes focus from far to near.
    • Accommodation decrease with age and is completely lost by age ~ 50.  
    • Loss of accommodation > loss of near vison.
    • Near vision can be corrected with reading glasses.  
    • Reading glasses cannot restore accommodation
    To develop a  system that can simultaneously measure the power of the eye and changes in the lens shape combining an adjustable accommodation stimulus, an autorefractor, and an Optical Coherence Tomography (OCT) system