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Nanotechnology Applications in Medicine
Published in Cherry Bhargava, Amit Sachdeva, Nanotechnology, 2020
Ashish Suttee, Neeraj Choudhary
Ophthalmology: To construct, repair, defend, monitor, control and improve the biological systems at molecular stage by means of nanodevices, nanostructures that work particularly at cellular level for achieving medical benefits is the goal of nanomedicines. Biomimicry, along with artificial intelligence and nanotechnology principles, are applied to develop nanomedicine. Nanoparticles have been used in the measurement of intraocular pressure, treatment of oxidative stress, the prevention of scars that occurs after glaucoma surgery, regenerative nanomedicine, the treatment of degenerative disease of the retina using gene therapy, and prosthetics are some of the applications of nanotechnology to ophthalmology. Postoperative scarring, sight-restoring therapy in patients suffering from degenerative retinal disease, and present-day drug delivery challenges can be resolved with the effective use of nanotechnology [29]. A nanoscale-dispersed eye ointment is used in curing severe evaporative dry eye. Excipients of conventional eye ointment, viz. petrolatum and lanolin, were attached to triglycerides as a lipid, followed by dispersion in polyvinyl pyrrolidone solution to develop nanodispersion [30].
Materials for Tissue Engineering
Published in Joseph W. Freeman, Debabrata Banerjee, Building Tissues, 2018
Joseph W. Freeman, Debabrata Banerjee
Hyaluronic acid is a naturally occurring linear anionic polysaccharide consisting of repeating disaccharide units, Figure 5.13. It is an important component of articular cartilage and is widely distributed in the connective tissue as well as vitreous and synovial fluids of mammals. The polymer is water soluble, forming very viscous solutions. Hyaluronic acid possesses several properties that make it an ideal candidate for wound dressing applications. It can act as a scavenger for free radicals in wounds, controlling inflammation. It can interact with a variety of biomolecules, is a bacteriostat, and can be recognized by receptors on a variety of cells associated with tissue repair. Cross-linked hyaluronic acid gels or hyaluronic acid derivatives such as ethyl/benzyl (HYAFF) esters have been investigated for wound-dressing applications. The rate of degradation and the solubility of the hyaluronic acid can be controlled by changing the extent of esterification. These derivatives can be fabricated into a variety of shapes such as membranes, fibers, sponges, and microspheres. High molecular-weight viscoelastic hyaluronic solutions (AMVISC and AMVISC PLUS) are used to protect delicate tissue in the eye during cataract extraction, corneal transplantation, and glaucoma surgery. Hyaluronic acid can act as a vitreous substitute during retina reattachment surgery. Injectable formulations of hyaluronic acid (SYNVISC, ORTHOVISC) have been developed to relieve pain and improve joint mobility in patients suffering from osteoarthritis.
Laser Processing and On-Line Monitoring for Biomedical Applications
Published in Savaş Kaya, Sasikumar Yesudass, Srinivasan Arthanari, Sivakumar Bose, Goncagül Serdaroğlu, Materials Development and Processing for Biomedical Applications, 2022
Guoqing Hu, Xuan Wang, Jingwen He, Jie Yang, Feng Zhao
Due to the unique advantages of laser surgery as demonstrated before, it provides an attractive alternative treatment tool. Besides, excimer laser photons have high energy exceeding the bond energy of many polymers. Its energy is sufficient to break molecular bonds of materials for material removal without heating. Thus, it is most suitable for the organic materials such as the components of the eye due to their weak bonds. Actually, research on the applications of laser eye surgery in ophthalmic diseases has lasted for tens of years (Alio 2014; McAlinden 2012; Mosquera et al. 2014). The first excimer laser surgery, executed already over 31 years ago, was a historical breakthrough (McDonald 1990). As demonstrated previously, the femtosecond laser processing could be a cold processing tool to effectively suppress thermal damage (Lo et al. 2012). In 1998, Kurtz et al. proposed the first experimental verification of femtosecond laser-assisted eye surgery (Kurtz et al. 1998). In 2000, Sacks et al. demonstrated the femtosecond laser cutting of the sclera in glaucoma surgery (Sacks et al. 2000). At that time, over five million people all over the world had become blind due to complications arising from glaucoma. In 2009, femtosecond laser-assisted cataract surgery was reported (Nagy et al. 2009). Nowadays, the systems of femtosecond laser-assisted cataract surgery (Grewal et al. 2015) and laser surgery of glaucoma and refractive error have been commercially produced for practical applications. The diagram of the optical and mechanical interface between the laser system and the eye is depicted as shown in Figure 12.2. For safety, an online monitoring subsystem (i.e. optical coherence tomography (OCT)) is also adopted for imaging. Nevertheless, higher precision and efficiency, lower cost, and better postoperative recovery are still a continuous pursuit.
Device profile of the EYEMATE-IO™ system for intraocular pressure monitoring: overview of its safety and efficacy
Published in Expert Review of Medical Devices, 2020
Philip Enders, Claus Cursiefen
The safety profile of the Eyemate-IO™ in this study was comparable to the safety profile in combined surgery with keratoprosthesis. Out of 22 POAG patients, surgical complications were reported in seven. Iris prolapse and pigment dispersion were most frequent (n = 5). The investigators counted four ocular SAEs after implantation. These were anterior chamber inflammatory response with accumulation of fibrin (n = 2), corneal decompensation (n = 1) and persisting IOP increase (n = 1) requiring consecutive glaucoma surgery. Anterior chamber inflammation leading to hospitalization in two cases occurred early after surgery and resolved promptly with intensified corticosteroid application. Seventy AEs in 18 patients were classified as at least possibly related to the Eyemate-IO™. Most frequent AEs were increased IOP (n = 22), anterior chamber inflammation with cells and flare (n = 11), and pigment dispersion (n = 8). Best-corrected visual acuity was improved and endothelium cell count in line with the typical mild loss after cataract surgery.
Compatibility and durability of the gel stent material
Published in Expert Review of Medical Devices, 2022
Vanessa Vera, Arsham Sheybani, William Wustenberg, Laszlo Romoda, Larissa Camejo, Xiongfei Liu, Richard Lewis
Successful glaucoma surgery must provide safe, long-term IOP reduction. With the XEN Gel Stent, the biggest concern was that the inner lumen of the stent would erode over time. A 10-year accelerated flow test was performed to evaluate the durability of the stent [30].