Volume 6, Issue 1, 2019
Nano-mechanical properties of novel intermetallic coatings on 316L bioimplant material
Muhammad Ans, Muhammad Atif Makhdoom, Ali Hassan
In the present work, nano-mechanical properties of intermetallic layer formed on 316L austenitic stainless steel have been investigated. Hot dip aluminizing technique applied on stainless steel samples for coating and composition of Al-Si alloys maintained as 8%, 10%, 12% and 14%. Nano-mechanical properties of the intermetallic formed have been evaluated using Nano-indentation technique at room temperature and results were compared. On the basis of our observations and obtained results it is concluded that with increasing silicon percentage the thickness of the intermetallic layer increases. However, the nano-mechanical results showed that this layer is brittle in nature. Therefore, it can be inferred that for bio-implant application the thickness of the layer needs to be at lower level as possible.
Volume 5, Issue 3-4, 2018
A review of chitosan-, alginate-, and gelatin-based biocomposites for bone tissue engineering
Bone diseases and injuries have a major impact on the quality of life. Classical treatments for bone repair/regeneration/replacement have various disadvantages. Bone tissue engineering (BTE) received a great attention in the last years. Natural polymers are intensively studied in this field due to their properties (biocompatibility, biodegradability, abundance in nature, high processability). Unfortunately, their mechanical properties are poor, which is why synthetic polymers or ceramics are added in order to provide the optimal compressive, elastic or fatigue strength. Moreover, growth factors, vitamins, or antimicrobial substances are also added to enhance the cell behavior (attachment, proliferation, and differentiation). In this review, new scientific results regarding potential applications of chitosan-, alginate-, and gelatin based biocomposites in BTE will be provided, along with their in vitro and/or in vivo tests.
Tissue engineered vascular grafts
With the continuous increase in the prevalence of cardiovascular diseases and the limited efficiency of conventional treatments, including diet and lifestyle modifications, pharmaceutical administration, and surgical interventions, there is an equally increased need for vascular grafts for the replacement of damaged blood vessels. Currently, autologous grafts represent the gold standard. However, due to the limited availability, intensive work has been performed in the field of vascular tissue engineering. Although there are many possibilities for obtaining synthetic vascular grafts, there is still no ideal solution for vascular replacements. In this paper, the main material categories and fabrication techniques are reviewed.
Volume 5, Issue 1-2, 2018
Strategies based on stem cells for tissue engineering
Cell-therapy is a new approach in medical research field. The increased number of patients, which is reported all over the world, has led to the development of innovative solutions capable of improving wound healing. Stem cells, due to their self-renewal and differentiation capacities, gradually replace the traditional medicine used in the past. Even if the risks of using stem cells exists, the promising results they can offer have led to the design of intelligent materials that can make life easier for patients. Stem cells can be classified by many criteria, but the most important are embryonic and adult stem cells. The ability of embryonic stem cells of differentiate into any type of tissue by various strategies makes them an ideal candidate in tissue engineering applications. Ethical problems must be taken into consideration, so the most used in different therapies are adult stem cells. Nowadays, the applications of stem cells are various. They can be used in order to restore the function of soft and hard tissue and to improve the healing time of a wound. Skin problems, osteogenesis, angiogenesis or fracture healing are some examples of tissue disorders that can be restored by using stem cells therapy and nanotechnology.
Volume 4, Issue 1-4, 2017
Nano-structured metal-semiconductor-metal photodetector for sensor network systems
Farzaneh Fadakar Masouleh, Narottam Das, Seyed Mohammad Rozati
The advanced and smart ways to produce complex nano-structures have incorporated new capabilities in various aspects of science and technology where structures on nano-meter scales are desirable including high-speed communication and sensor networks, and future biomedical sensors and detectors. In recent years, there has been a growing interest towards the miniaturization of optical and electrical components with faster and more efficient performance. The development of nano-materials and nano-structures design provides great opportunity for building multifunctional sensing elements which are smaller and more efficiently incorporated. Furthermore they have other useful characteristics like reduced production cost and minimized power consumption. Wireless sensor network systems have been identified as one of the most important technologies for the 21st century (Chong et. al., 2003). It can be deduced from its name that sensor network systems are composed of several sensor nodes, where each component is responsible for a function in the whole system, where it can consist of different kinds of sensors such as, thermal, visual, biomedical, infrared, acoustics, etc. Recent wireless communication system development requires a concurrent speedy advancement of sensors characteristics as well as the system performance. Therefore, it is very important to make the progress in sensors design with tiny dimensions, suitable for communication over a sensor network system with specified purposes such as, monitoring different parameters, namely humidity, temperature, light in household, cities, and different environments (Ian-Akyildiz et al., 2002). The main focus of this review is to design and model an optimized plasmonics-based metal-semiconductor-metal photodetectors (MSM-PDs) with sub-wavelength architectures that is useful for high-speed optical communication systems and sensor network systems. Nano-structures designed on top of the electrodes trigger surface plasmon polaritons (SPPs) excitation and enable routing and manipulation of the light to be eventually trapped into the device active region.
Organic-inorganic antimicrobial nanostructures for health care applications
Shivaji Hariba Pawar, Sonali Suresh Rohiwal, Jatinder Yakhmi
In recent years, the drug resistant microorganisms are a serious and increasing public health problem. New strategies for controlling bacteria activity are urgently needed and nanomaterials can be a very promising approach, as the small size of the particle gives large surface area and consequently reactivity (and in many cases toxicity) increases substantially. The most tested metallic nanoparticles are silver, copper, gold, aluminum, titanium, iron, zinc, bismuth and others. Some of these metals have been coated onto several other materials. Another strategy is to incorporate these metals into a substrate such as polymethyl methacrylate forming organic-inorganic antimicrobial nanostructures. With respect to bacteria and fungi, the most frequent candidates for microbial experiments are: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, Bacillus subtilis among other species. The antimicrobial potential of these nanostructured particles, their mechanism of action and health care applications are presented and discussed at length in this review.
Nanostructures and their application in antimicrobial drug delivery system
Thakur Gurjeet Singh, Kashish Malhotra, Mayank Sippy, Sonia Dhiman
As multiresistant and pan-resistant infections continue to emerge, and because the development of novel antimicrobial drugs is a slow process, nanotechnology offers valuable alternatives for fighting resistant bugs, mainly by improving the therapeutic effect of current antimicrobials. Antibiotic resistance is one of the greatest global health threats of the 21st century, but nanotechnology is offering new solutions to the problem. Nanostructured biomaterials, nanoparticles in particular, have unique physicochemical properties such as ultra small and controllable size, large surface area to mass ratio, high reactivity, and functionalizable structure. These properties can be applied to facilitate the administration of antimicrobial drugs, thereby overcoming some of the limitations in traditional antimicrobial therapeutics. Carbon-based nanomaterials such as fullerenes, carbon nanotubes (CNTs) (especially single-walled carbon nanotubes (SWCNTs)) and graphene oxide (GO) nanoparticles) show potent antimicrobial properties. Nanocoating and shuttle systems have shown great promise in vitro and animal models. Noble metals nanostructures, particularly silver, have attracted much attention in the fields of medicine due to their unique properties which are strongly dependent on the size and shape of metal nanomaterials. Recent development of nanocarriers, improved the drug therapy of different diseases, together with the mechanisms of microbial inhibition.
Volume 3, Issue 1-4, 2016
Applications of transition metal nanoparticles in antimicrobial therapy
Arunachalam Dinesh Karthik, Kannappan Geetha
Nanotechnology is expected to open some new aspects to fight and prevent diseases using atomic scale tailoring of materials. The ability to uncover the structure and function of bio systems at the nanoscale, stimulates research leading to improvement in biology, biotechnology, medicine and healthcare. The size of nanomaterials is similar to that of most biological molecules and structures; therefore, nanomaterials can be useful for both in vivo and in vitro biomedical research and applications. The integration of nanomaterials with biology has led to the development of diagnostic devices, contrast agents, analytical tools, physical therapy applications, and drug delivery vehicles. In all the nanomaterials with antibacterial properties, metallic nanoparticles are the best. Nanoparticles increase chemical activity due to crystallographic surface structure with their large surface to volume ratio. The importance of bactericidal nanomaterials study is because of the increase in new resistant strains of bacteria against most potent antibiotics. This has promoted research in the well known activity of silver ions and silver-based compounds, including Cu, Ag, Zn, Cd and Ni nanoparticles. This effect was size and dose dependent and was more pronounced against gram-negative bacteria than grampositive organisms. Also, Biosynthesis of nanoparticles is under exploration is due to wide biomedical applications and research interest in nanotechnology. The biological approach for the synthesis of nanoparticles is considered as more eco-friendly and cost effective as compared to the other chemical and physical approaches. This review detailed view about the Nanostructures antimicrobial Therapy of metal nanoparticles.
Application of nanoparticles in oral hygiene
Shams Tabrez Khan, Abdulaziz A. Al-Khedhairy, Javed Musarrat, Maqusood Ahamed
Many of more than 700 bacterial species inhabiting the oral cavity are opportunistic pathogens causing systemic infections in addition to dental and periodontal diseases. This renders oral hygiene a much serious issue, which is further exacerbated with the emergence of multiple antibiotic resistance in oral bacteria. The role of nanoparticles based materials especially metal and metal oxide nanoparticles as an effective and alternative/supplementary antimicrobial agent is now well established. These nanoparticles could be a healthier, innocuous and effective alternative for controlling both the dental biofilms and oral planktonic bacterial population with lesser side effects or antibiotic resistance. Antimicrobial activity of these nanoparticles against a number of oral pathogens has already been demonstrated. When added to artificial dental materials and implants these nanoparticles improve the desirable physico-chemical properties of the materials in addition to improving their antimicrobial activity. Besides a few studies, biochemical processes underlying the antimicrobial activity of the nanoparticles against both planktonic cells and oral biofilms is not understood. Through our literature survey it is envisaged that ZnO nanoparticles and TiO2 nanoparticles are the most suitable nanoantibiotic for the development of dental pastes, mouthwashes, and other oral hygiene materials. However in vivo studies on nanotoxicity of these nanoparticles are missing and need a careful and balanced evaluation before successful clinical translations.
Volume 2, Issue 1-4, 2015
In vitro evaluation of the antibacterial activity of modified multi-walled carbon nanotubes with phenolic extracts
Mahdieh Entezari, Zohreh Ghazi Tabatabaei, Amin Azarioun, Sanaz Sarabian, Ghazal Taghizadeh Farahani
Conventional Antibiotics such as ciprofloxacin, ofloxacin and levofloxacin are an important group of antimicrobials which are widely used in the treatment of various infectious diseases. Long-term treatment with antibiotics can cause side effects in consumers. Bactericidal antibiotics may persuade the establishment of toxic reactive oxygen types (ROS) in bacteria. In the present study, we tried to eliminate the side effects of antibiotics by modification of multi wall carboxylated nanotubes with phenolic extractives that are extracted of pigmented vegetables. Very low concentrations of functionalized nanotubes were tested against both Gram-positive and Gram-negative bacteria. Antibacterial activity of the products was compared with MIC values of conventional antibiotics. In vitro studies represented that killed bacteria in the presence of low concentrations of modified nanotubes. so, the extremely abilities of functionalized carboxylated multiwall nanotubes have the potential to be described as innocuous antibiotic candidates.
Effects of hypericin on the oxidative stress and modulation of cytochrome P450 (CYP1A) activity in microsomes
Renata Kubínová, Václav Suchý, Marie Valentová
Hypericin is a pigment present in the widely distributed medicinal plant Hypericum perforatum L. (Hypericaceae). In our research, hypericin was found to be an inhibitor of NADPH/Fe2+ induced microsomal lipid peroxidation and NADPH-dependent lucigenin chemiluminescence emission in vitro. Hypericin also inhibited the microsomal CYP1Adependent 7-ethoxyresorufin O-deethylase (EROD) which participates in the metabolic activation of xenobiotics including chemical carcinogens.
Volume 1, Issue 1-4, 2014
Local delivery of tetracycline from γ-aminobutiric acid-silica networks thin films for preventing microbial colonization
Alina Maria Holban, Ecaterina Andronescu, Valentina Grumezescu, Gabriel Socol, Alexandru Mihai Grumezescu, Veronica Lazar, Mariana Carmen Chifiriuc
The purpose of this study was to characterize and evaluate the citotoxicity and antimicrobial activity of γaminobutiric acid-silica/tetracycline network thin films prepared by Matrix Assisted Pulsed Laser Evaporation (MAPLE). Thin films were characterized by Infrared Microscopy (IRM), X-ray Diffraction (XRD), Transmision Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). TEM images showed an average size of gammaaminobutiric acid-silica network (γ-AA/SiO2) lower than 10 nm. Unlike the dropcast samples, IRM recorded on MAPLE films revealed a good distribution of monitored functional groups on the entire scanned surface. Besides a good homogeneity of the coatings, SEM analysis revealed aggregates typical for MAPLE deposition, randomly distributed on the surface with an average diameter of ~300 nm. The biological evaluation of MAPLE nanobiocoated surfaces evidenced a good biocompatibility and an enhanced antibiofilm effect against both Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) tested strains. Our results recommend the use of γ-aminobutiric acid-silica networks as matrixes for controlled local delivery of antibiotics, with practical applications in developing improved medical surfaces for the prevention or reduction of surface-associated microbial infections.
In vitro cytocompatibility evaluation of collagen based scaffolds using human endothelial progenitor cells for vascular tissue engineering
Florin Iordache, Andrei Constantinescu, Eugen Andrei, Carmen Curuțiu, Alexandru Mihai Grumezescu, Georgeta Voicu, Horia Maniu
Vascular tissue engineering attempts to grow blood vessels through the use of different scaffolds that allows vascular cells such as endothelial cells to form networks and organized in vascular tissue. Various biomaterials are used to produce scaffolds that allow growth and differentiation of stem cells; depending on the cell type and applications some materials are more suitable than other. The aim of this study was to evaluate the cytocompatibility of collagen based scaffolds and to assess the capacity of endothelial progenitor cells (EPC) isolated from human umbilical cord to form vascular networks on these scaffolds. Our results show that after 5 days in culture with collagen scaffolds, the EPC remained viable, a sign of biocompatibility with the 3D scaffolds. Scanning electron microscopy showed that in the collagen scaffolds EPC organize within networks and presents an abundant extracellular matrix that strengthen the links between them. When EPC were cultured on collagenchitosan scaffolds, they are more adherent to the scaffolds compared with collagen, exibiting a good capacity to form networks. This study shows that the collagen and collagen-chitosan scaffolds are not cytotoxic for EPC and they provide the possibility of being used in vascular tissue engineering to help creating blood vessels.