Stefania Marin

Bio: Stefania Marin is an academic researcher from Politehnica University of Bucharest. The author has contributed to research in topics: Silver nanoparticle & Self-healing hydrogels. The author has an hindex of 5, co-authored 16 publications receiving 255 citations.

Applications and toxicity of silver nanoparticles: a recent review.

Abstract: Silver nanoparticles (AgNPs) exhibit a consistent amount of flexible properties which endorse them for a larger spectrum of applications in biomedicine and related fields. Over the years, silver nanoparticles have been subjected to numerous in vitro and in vivo tests to provide information about their toxic behavior towards living tissues and organisms. Researchers showed that AgNPs have high antimicrobial efficacy against many bacteria species including Escherichia coli, Neisseria gonorrhea, Chlamydia trachomatis and also viruses. Due to their novel properties, the incorporation of silver nanoparticles into different materials like textile fibers and wound dressings can extend their utility on the biomedical field while inhibiting infections and biofilm development. Among the noble metal nanoparticles, AgNPs present a series of features like simple synthesis routes, adequate and tunable morphology, and high surface to volume ratio, intracellular delivery system, a large plasmon field area recommending them as ideal biosensors, catalysts or photo-controlled delivery systems. In bioengineering, silver nanoparticles are considered potentially ideal gene delivery systems for tissue regeneration. The remote triggered detection and release of bioactive compounds of silver nanoparticles has proved their relevance also in forensic sciences. The authors report an up to date review related to the toxicity of AgNPs and their applications in antimicrobial activity and biosensors for gene therapy.

New collagen-dextran-zinc oxide composites for wound dressing

Abstract: The goal of this paper was the design, development, and characterization of some new composites, based on collagen and dextran as natural polymers and zinc oxide as antimicrobial, to be used in wound healing. Collagen hydrogels with various concentrations of dextran and zinc oxide were investigated in terms of rheological analysis. The spongious composites, obtained by freeze-drying of hydrogels, were evaluated by morphology (SEM), water uptake, and biological (enzymatic biodegradation) analysis. All the results were strongly influenced by the nature and concentration of composite components. Based on the performances of the hydrogels, stationary rheometry, porous structure, morphology, and biological behavior, the antimicrobial spongious composite based on collagen and dextran with 50% ZnO were the most promising for future applications in wound dressing and a biomaterial with high potential in skin regeneration.

Silver nanoparticles in cancer therapy

Abstract: Silver nanoparticles have attracted significant attention from researchers because of their large number of applications, such as medical imaging, filters, drug delivery, nanocomposites, cell electrodes, and antimicrobial products. Plenty of studies revealed advantageous size- and shape-depending properties, which can be used in order to achieve complex systems for various purposes. Silver nanoparticles can be obtained by many methods but the most used technique is green synthesis. In this method, silver nanoparticles can be easily synthesized by manipulating different microorganisms or plants including: green tea (Camellia sinensis), alfalfa (Medicago sativa), lemongrass (Cymbopogon flexuosus), and Brassica juncea. The elimination of toxic and expensive chemical substances is the most substantial benefit. Due to their novel properties, silver nanoparticles are considered potentially ideal for cancer therapy. In recent years, numerous studies have claimed that silver nanoparticles can be successfully used as antitumor agents due to their antiproliferative and apoptosis-inducing properties. Both in vivo and in vitro tests have been performed on various types of cancer cells in order to correlate the physical properties of nanosilver and the administered doses with a satisfactory effect on tumor and the healthy tissues surrounding it. However, for silver nanoparticles to become influential in nanomedicine and for patient safety, all the mechanisms related to their anticancer activity must be understood.

Innovative Biomaterials Based on Collagen-Hydroxyapatite and Doxycycline for Bone Regeneration

Abstract: Bone regeneration is a serious challenge in orthopedic applications because of bone infections increase, tumor developing, and bone loss due to trauma. In this context, the aim of our study was to develop innovative biomaterials based on collagen and hydroxyapatite (25, 50, and 75%) which mimic bone composition and prevent or treat infections due to doxycycline content. The biomaterials were obtained by freeze-drying in spongious forms and were characterized by water uptake capacity and microscopy. The in vitro release of doxycycline was also determined and established by non-Fickian drug transport mechanism. Among the studied biomaterials, the most suitable one to easily deliver the drug and mimic bone structure, having compact structure and lower capacity to uptake water, was the one with 75% hydroxyapatite and being cross-linked.

Collagen-Carboxymethylcellulose Biocomposite Wound-Dressings with Antimicrobial Activity.

Abstract: Microbial infections associated with skin diseases are frequently investigated since they impact on the progress of pathology and healing. The present work proposes the development of freeze-dried, glutaraldehyde cross-linked, and non-cross-linked biocomposite dressings with a porous structure, which may assist the reepithelization process through the presence of collagen and carboxymethylcellulose, along with a therapeutic antimicrobial effect, due to silver nanoparticles (AgNPs) addition. Phisyco-chemical characterization revealed the porous morphology of the obtained freeze-dried composites, the presence of high crystalline silver nanoparticles with truncated triangular and polyhedral morphologies, as well as the characteristic absorption bands of collagen, silver, and carboxymethylcellulose. In vitro tests also assessed the stability, functionality, and the degradability rate of the obtained wound-dressings. Antimicrobial assay performed on Gram-negative (Escherichia coli), Gram-positive (Staphyloccocus aureus) bacteria, and yeast (Candida albicans) models demonstrated that composite wound dressings based on collagen, carboxymethylcellulose, and AgNPs are suitable for skin lesions because they prevent the risk of infection and have prospective wound healing capacity. Moreover, the cell toxicity studies proved that the obtained materials can be used in long time treatments, with no cytotoxic effects.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Treatment Strategies for Infected Wounds.

Abstract: The treatment of skin wounds is a key research domain owing to the important functional and aesthetic role of this tissue. When the skin is impaired, bacteria can soon infiltrate into underlying tissues which can lead to life-threatening infections. Consequently, effective treatments are necessary to deal with such pathological conditions. Recently, wound dressings loaded with antimicrobial agents have emerged as viable options to reduce wound bacterial colonization and infection, in order to improve the healing process. In this paper, we present an overview of the most prominent antibiotic-embedded wound dressings, as well as the limitations of their use. A promising, but still an underrated group of potential antibacterial agents that can be integrated into wound dressings are natural products, especially essential oils. Some of the most commonly used essential oils against multidrug-resistant microorganisms, such as tea tree, St. John’s Wort, lavender and oregano, together with their incorporation into wound dressings are presented. In addition, another natural product that exhibits encouraging antibacterial activity is honey. We highlight recent results of several studies carried out by researchers from different regions of the world on wound dressings impregnated with honey, with a special emphasis on Manuka honey. Finally, we highlight recent advances in using nanoparticles as platforms to increase the effect of pharmaceutical formulations aimed at wound healing. Silver, gold, and zinc nanoparticles alone or functionalized with diverse antimicrobial compounds have been integrated into wound dressings and demonstrated therapeutic effects on wounds.

Особливості структурно-функціональної організації техногенно зміненої водної екосистеми гирлової ділянки річки Ірпінь. Кваліфікаційна праця на правах рукопису

Abstract: Писанко Я. І. Особливості структурно-функціональної організації техногенно зміненої водної екосистеми гирлової ділянки річки Ірпінь. : автореф. дис. на здобуття наук. ступеня канд. техн. наук : спец. 21.06.01 "Екологічна безпека" / Писанко Яна Іванівна – Київ. – 26 с.