The eye is a complex organ consisting of several protective barriers and particular defense mechanisms. Since this organ is exposed to various infections, genetic disorders, and visual impairments it is essential to provide necessary drugs through the appropriate delivery routes and vehicles. The topical route of administration, as the most commonly used approach, maybe inefficient due to low drug bioavailability. New generation safe, effective, and targeted drug delivery systems based on nanocarriers have the capability to circumvent limitations associated with the complex anatomy of the eye. Nanotechnology, through various nanoparticles like niosomes, liposomes, micelles, dendrimers, and different polymeric vesicles play an active role in ophthalmology and ocular drug delivery systems. Niosomes, which are nano-vesicles composed of non-ionic surfactants, are emerging nanocarriers in drug delivery applications due to their solution/storage stability and cost-effectiveness. Additionally, they are biocompatible, biodegradable, flexible in structure, and suitable for loading both hydrophobic and hydrophilic drugs. These characteristics make niosomes promising nanocarriers in the treatment of ocular diseases. Hereby, we review niosome based drug delivery approaches in ophthalmology starting with different preparation methods of niosomes, drug loading/release mechanisms, characterization techniques of niosome nanocarriers and eventually successful applications in the treatment of ocular disorders.

Due to the resistance to drugs, studies involving the combination and controlled release of different agents are gradually increasing. In this study, two different active ingredients, known to have antibacterial and antiparasitic activities, were encapsulated into single polymeric nanoparticles. After co-encapsulation their antibacterial and antileishmanial activity was enhanced approximately 5 and 250 times, respectively. Antibacterial and antileishmanial activities of caffeic acid phenethyl ester and juglone loaded, multifunctional nanoformulations (CJ4-CJ6-CJ8) were also evaluated for the first time in the literature comparatively with their combined free formulations. The antibacterial activity of the multifunctional nanoformulation (CJ8) were found to have a much higher activity (MIC values 6.25 and 12.5 μg ml −1 for S. aureus and E. coli, respectively) than all other formulations. Similar efficacy for CJ8 was obtained in the antiparasitic study against the Leishmania promastigotes and the IC 50 was reduced to 0.1263 μg ml −1 . The high activity of multifunctional nanoparticles is not only due to the synergistic effect of the active molecules but also by the encapsulation into polymeric nanoparticles. Therefore, it has been shown in the literature for the first time that the biological activity of molecules whose activity is increased by the synergistic effect can be improved with nanosystems.

Objectives: The skin is a multifunctional organ that covers up the entire surface of the body. Material properties such as hyperelasticity, viscoelasticity and plasticity are very important for the development of new biological materials. The main focus of this study is to investigate the biomechanical properties of the dermis and to examine how these vary according to different body parts. Methods: Skin samples were dissected from various parts of the body. All skin samples were tested in uniaxial tension parallel to their long axis. A strength-elongation curve was obtained and the maximum strength and maximum elongation values were determined from this curve for each tensile test performed. Reaction forces and displacements were determined by software. Results: The results of our study showed a statistically significant difference in the evaluation between the scalp, face, upper and lower extremities for elastic modulus, tensile strength and thickness. It has been observed that the elastic modulus, tensile strength and thickness values vary depending on the topographic region of the body. According to our results, the upper extremity showed the highest elastic modulus among all regions (42.70 ± 8.92 MPa). The highest tensile strength was also measured for the upper extremity skin and its value was determined as 17.72 ± 4.00 MPa. Conclusions: Data obtained from this study may provide valuable information for modeling purposes, basic data for tissue grafts and comparison of tissue characteristics after head trauma or forensic examinations.

The current COVID-19 pandemic has affected more than 100 million people and resulted in morbidity and mortality around the world. Even though the disease caused by SARS-CoV-2 is characterized by respiratory tract involvement, previous and recent data also indicates ocular manifestation. Not surprisingly, cell entry point of the virus, ACE2 receptor, is widely expressed in ocular tissues ranging from conjunctiva to retina. Despite the sensibility of ocular tissues, the sophisticated defense mechanism of the eye might eliminate viral transmission. Nevertheless, the potential of systemic transmission through the nasolacrimal duct may not be eliminated. In the case of ocular involvement, the disease outcomes might be as treatable as conjunctivitis or as serious as retinal degeneration and the treatment regimen vary accordingly. Within these contingencies, our aim with this chapter is to shed light on molecular bases of SARS-CoV-2 infection, systemic invasiveness following ocular transmission, manifestation and permanent effects on ocular tissues.