Natural and Artificial Superwettable Surfaces-Superficial Phenomena: An Extreme Wettability Scenario

With the help of biomimetics, superficial characteristics were transposed, through various methods, onto artificially obtained materials. Many industrial fields applied surface architecture modifications as improvements of classic materials/methods. The medico-pharmaceutical, biochemical, transportation, and textile fields are few examples of industrial areas welcoming a “structural change.” Anti-bioadhesion was widely exploited by means of antibacterial or self-cleaning fabrics and cell culturing/screening/isolation. Anti-icing, antireflective, and anticorrosion materials/coatings gained attention in the transportation and optical device fields. Interdisciplinary approaches on extreme wettability include “solid-fluid” formations called liquid marbles, which will be further discussed as a superhydrophobic behavior exponent

Chitosan: A Good Candidate for Sustained Release Ocular Drug Delivery Systems

This chapter focuses on the eye, one of the most important organs of humans. Current data on pathophysiology of the human eye are presented in direct correlation with a range of therapeutic products, with a well-known and widely used material, namely chitosan. Applications of chitosan biopolymer are described in the development of innovative, modern, therapeutic devices and solutions. Thus, chitosan is a good excipient either for classic drop-type ocular systems, as well as for complex drug systems such as nanostructures (nanoparticles, nanomicelles and nanosuspensions), liposomes, microemulsions, microspheres, in situ hydrogels and inserts or implants. A number of disadvantages for ocular administration of the drugs are thus overcome

Promising Hydrogels-Based Dressings for Optimal Treatment of Cutaneous Lesions

Worldwide, cutaneous lesions care represents a daily challenge for the medical system, with an increasing prevalence from year to year (from ~5 million in 2005 to about 8 million in 2018) and high costs for their treatment (between ~$28 billion and ~$97 billion). Injuries are the most frequent and destructive form of skin damage, affecting patients’ quality of life. To promote wound healing, an ideal treatment involves proper dressings that can manage the local pain, inflammation, or infection. Passive or dry traditional dressings, such as cotton, gauze, or lint, have limited therapeutic actions and demand periodic replacement of the dressing. Therefore, an optimal alternative for advanced wound care is represented by hydrogels, one of the five classes of modern dressings, which assure excellent local moisture, due to their high ability to absorb a large volume of water inside their three-dimensional networks. Moreover, hydrogels possess suitable biocompatibility, biodegradability, porosity, elasticity, flexibility, and biological properties similar to the extracellular matrix. This chapter presents the main characteristics of the hydrogels and the recent research regarding the development of new hydrogel dressings, based on natural, semi-synthetic, or synthetic biopolymers, loaded with varied therapeutic agents to stimulate the tissue regeneration of different etiologies cutaneous lesions

Melatonin: A Silent Regulator of the Glucose Homeostasis

In the human organism, the circadian regulation of carbohydrates metabolism is essential for the glucose homeostasis and energy balance. Unbalances in glucose and insulin tissue and blood levels have been linked to a variety of metabolic disorders such as obesity, metabolic syndrome, cardiovascular diseases and type 2 diabetes. Melatonin, the pineal hormone, is the key mediator molecule for the integration between the cyclic environment and the circadian distribution of physiological and behavioral processes and for the optimization of energy balance and body weight regulation, events that are crucial for a healthy organism. This chapter reviews the interplay between melatonin modulatory physiological effects, glucose homeostasis and metabolic balance, from the endocrinology perspective. The tremendous effect of melatonin in the regulation of metabolic processes is observed from the chronobiology perspective, considering melatonin as a major synchronizer of the circadian internal order of the physiological processes involved in energy metabolism

Hydrogels - Smart Materials for Biomedical Applications

Hydrogels, as three-dimensional polymer networks, are able to retain a large amount of water in their swollen state. The biomedical application of hydrogels was initially hampered by the toxicity of cross-linking agents and the limitations of hydrogel formation under physiological conditions. However, emerging knowledge in polymer chemistry and an increased understanding of biological processes have resulted in the design of versatile materials and minimally invasive therapies.The novel but challenging properties of hydrogels are attracting the attention of researchers in the biological, medical, and pharmaceutical fields. In the last few years, new methods have been developed for the preparation of hydrophilic polymers and hydrogels, which may be used in future biomedical and drug delivery applications. Such efforts include the synthesis of self-organized nanostructures based on triblock copolymers with applications in controlled drug delivery. These hydrogels could be used as carriers for drug delivery when combined with the techniques of drug imprinting and subsequent release. Engineered protein hydrogels have many potential advantages. They are excellent biomaterials and biodegradables. Furthermore, they could encapsulate drugs and be used in injectable forms to replace surgery, to repair damaged cartilage, in regenerative medicine, or in tissue engineering. Also, they have potential applications in gene therapy, although this field is relatively new

Flow and Thixotropic Parameters for Rheological Characterization of Hydrogels

The goal of this paper was to design several sodium carboxymethylcellulose hydrogels containing a BCS class II model drug and to evaluate their flow and thixotropic properties. The rheological measurements were performed at two temperatures (23 °C and 37 °C), using a rotational viscometer. The hydrogels were stirred at different time intervals (10 s, 2, 5, 10 and 20 min at 23 °C, and 10 s, 2 and 5 min at 37 °C), with a maximum rotational speed of 60 rpm, and the corresponding forward and backward rheograms were recorded as shear stress vs. shear rate. For all hydrogels, the rheological data obtained at both temperatures showed a decrease of viscosity with the increase of the shear rate, highlighting a pseudoplastic behaviour. The flow profiles viscosity vs. shear rate were quantified through power law model, meanwhile the flow curves shear stress vs. shear rate were assessed by applying the Herschel-Bulkley model. The thixotropic character was evaluated through different descriptors: thixotropic area, thixotropic index, thixotropic constant and destructuration thixotropic coefficient. The gel-forming polymer concentration and the rheological experiments temperature significantly influence the flow and thixotropic parameters values of the designed hydrogels. The rheological characteristics described have an impact on the drug release microenvironment and determine the stasis time at the application site

Ethnomedicinal, Phytochemical and Pharmacological Profile of Anthriscus sylvestris as an Alternative Source for Anticancer Lignans

Anthriscus sylvestris (L.) Hoffm. is a wild herbaceous plant common in most temperate regions. It has been used traditionally to treat headaches, as a tonic, as antitussive, antipyretic, analgesic and diuretic. The plant contains deoxypodophyllotoxin, which is proven to have antitumor and anti-proliferative effects, anti-platelet aggregation, antiviral, anti-inflammatory and insecticidal activity. Deoxypodophyllotoxin is considered to be the plant’s most important constituent, because of its pharmacological properties and because it can be converted into epipodophyllotoxin, the main raw material for the semisynthesis of the cytostatic agents etoposide and teniposide. This work summarizes for the first time the results related to the botanical description, distribution and habitat, phytochemical and pharmacological properties and emphasizes the aspects for future biotechnological research to establish its utility in the therapeutic arsenal

Bacterial Cellulose—A Remarkable Polymer as a Source for Biomaterials Tailoring

Nowadays, the development of new eco-friendly and biocompatible materials using ‘green’ technologies represents a significant challenge for the biomedical and pharmaceutical fields to reduce the destructive actions of scientific research on the human body and the environment. Thus, bacterial cellulose (BC) has a central place among these novel tailored biomaterials. BC is a non-pathogenic bacteria-produced polysaccharide with a 3D nanofibrous structure, chemically identical to plant cellulose, but exhibiting greater purity and crystallinity. Bacterial cellulose possesses excellent physicochemical and mechanical properties, adequate capacity to absorb a large quantity of water, non-toxicity, chemical inertness, biocompatibility, biodegradability, proper capacity to form films and to stabilize emulsions, high porosity, and a large surface area. Due to its suitable characteristics, this ecological material can combine with multiple polymers and diverse bioactive agents to develop new materials and composites. Bacterial cellulose alone, and with its mixtures, exhibits numerous applications, including in the food and electronic industries and in the biotechnological and biomedical areas (such as in wound dressing, tissue engineering, dental implants, drug delivery systems, and cell culture). This review presents an overview of the main properties and uses of bacterial cellulose and the latest promising future applications, such as in biological diagnosis, biosensors, personalized regenerative medicine, and nerve and ocular tissue engineering