Ana-Iulia Bița

Scopus Publications

Mechanical and Computational Fluid Dynamic Models for Magnesium-Based Implants
Veronica Manescu (Paltanea), Gheorghe Paltanea, Aurora Antoniac, Lucian Gheorghe Gruionu, Alina Robu, Marius Vasilescu, Stefan Alexandru Laptoiu, Ana Iulia Bita, Georgiana Maria Popa, Andreea Liliana Cocosila,et al.
MDPI AG
Today, mechanical properties and fluid flow dynamic analysis are considered to be two of the most important steps in implant design for bone tissue engineering. The mechanical behavior is characterized by Young’s modulus, which must have a value close to that of the human bone, while from the fluid dynamics point of view, the implant permeability and wall shear stress are two parameters directly linked to cell growth, adhesion, and proliferation. In this study, we proposed two simple geometries with a three-dimensional pore network dedicated to a manufacturing route based on a titanium wire waving procedure used as an intermediary step for Mg-based implant fabrication. Implant deformation under different static loads, von Mises stresses, and safety factors were investigated using finite element analysis. The implant permeability was computed based on Darcy’s law following computational fluid dynamic simulations and, based on the pressure drop, was numerically estimated. It was concluded that both models exhibited a permeability close to the human trabecular bone and reduced wall shear stresses within the biological range. As a general finding, the proposed geometries could be useful in orthopedics for bone defect treatment based on numerical analyses because they mimic the trabecular bone properties.

Chitosan-Based Biomaterials for Hemostatic Applications: A Review of Recent Advances
Daniela Gheorghiță, Horațiu Moldovan, Alina Robu, Ana-Iulia Bița, Elena Grosu, Aurora Antoniac, Iuliana Corneschi, Iulian Antoniac, Alin Dănuț Bodog, and Ciprian Ionuț Băcilă
MDPI AG
Hemorrhage is a detrimental event present in traumatic injury, surgery, and disorders of bleeding that can become life-threatening if not properly managed. Moreover, uncontrolled bleeding can complicate surgical interventions, altering the outcome of surgical procedures. Therefore, to reduce the risk of complications and decrease the risk of morbidity and mortality associated with hemorrhage, it is necessary to use an effective hemostatic agent that ensures the immediate control of bleeding. In recent years, there have been increasingly rapid advances in developing a novel generation of biomaterials with hemostatic properties. Nowadays, a wide array of topical hemostatic agents is available, including chitosan-based biomaterials that have shown outstanding properties such as antibacterial, antifungal, hemostatic, and analgesic activity in addition to their biocompatibility, biodegradability, and wound-healing effects. This review provides an analysis of chitosan-based hemostatic biomaterials and discusses the progress made in their performance, mechanism of action, efficacy, cost, and safety in recent years.

INFLUENCE OF HEAT TREATMENT ON MICROSTRUCTURE AND CORROSION BEHAVIOR OF BIODEGRADABLE Mg-Ca ALLOY

Construction of a magnesium hydroxide/graphene oxide/hydroxyapatite composite coating on Mg–Ca–Zn–Ag alloy to inhibit bacterial infection and promote bone regeneration
Bo Yuan, Hewei Chen, Rui Zhao, Xuangeng Deng, Guo Chen, Xiao Yang, Zhanwen Xiao, Antoniac Aurora, Bita Ana Iulia, Kai Zhang,et al.
Elsevier BV

Failure Analysis of Ultra-High Molecular Weight Polyethylene Tibial Insert in Total Knee Arthroplasty
Veronica Manescu (Paltanea), Iulian Antoniac, Aurora Antoniac, Gheorghe Paltanea, Marian Miculescu, Ana-Iulia Bita, Stefan Laptoiu, Marius Niculescu, Alexandru Stere, Costel Paun,et al.
MDPI AG
Knee osteoarthritis is treated based on total knee arthroplasty (TKA) interventions. The most frequent failure cause identified in surgical practice is due to wear and oxidation processes of the prothesis’ tibial insert. This component is usually manufactured from ultra-high molecular weight polyethylene (UHMWPE). To estimate the clinical complications related to a specific prosthesis design, we investigated four UHMWPE tibial inserts retrieved from patients from Clinical Hospital Colentina, Bucharest, Romania. For the initial analysis of the polyethylene degradation modes, macrophotography was chosen. A light stereomicroscope was used to estimate the structural performance and the implant surface degradation. Scanning electron microscopy confirmed the optical results and fulfilled the computation of the Hood index. The oxidation process in UHMWPE was analyzed based on Fourier-transform infrared spectroscopy (FTIR). The crystallinity degree and the oxidation index were computed in good agreement with the existing standards. Mechanical characterization was conducted based on the small punch test. The elastic modulus, initial peak load, ultimate load, and ultimate displacement were estimated. Based on the aforementioned experimental tests, a variation between 9 and 32 was found in the case of the Hood score. The oxidation index has a value of 1.33 for the reference sample and a maximum of 9.78 for a retrieved sample.

Essential Oils as Antimicrobial Active Substances in Wound Dressings
Daniela Gheorghita, Elena Grosu, Alina Robu, Lia Mara Ditu, Iuliana Mihaela Deleanu, Gratiela Gradisteanu Pircalabioru, Anca-Daniela Raiciu, Ana-Iulia Bita, Aurora Antoniac, and Vasile Iulian Antoniac
MDPI AG
Wound dressings for skin lesions, such as bedsores or pressure ulcers, are widely used for many patients, both during hospitalization and in subsequent treatment at home. To improve the treatment and shorten the healing time and, therefore, the cost, numerous types of wound dressings have been developed by manufacturers. Considering certain inconveniences related to the intolerance of some patients to antibiotics and the antimicrobial, antioxidant, and curative properties of certain essential oils, we conducted research by incorporating these oils, based on polyvinyl alcohol/ polyvinyl pyrrolidone (PVA/PVP) biopolymers, into dressings. The objective of this study was to study the potential of a polymeric matrix for wound healing, with polyvinyl alcohol as the main material and polyvinyl pyrrolidone and hydroxypropyl methylcellulose (HPMC) as secondary materials, together with additives (plasticizers poly(ethylene glycol) (PEG) and glycerol), stabilizers (Zn stearate), antioxidants (vitamin A and vitamin E), and four types of essential oils (fennel, peppermint, pine, and thyme essential oils). For all the studied samples, the combining compatibility, antimicrobial, and cytotoxicity properties were investigated. The obtained results demonstrated a uniform morphology for almost all the samples and adequate barrier properties for contact with suppurating wounds. The results show that the obtained samples containing essential oils have a good inhibitory effect on, or antimicrobial properties against, Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Candida albicans ATCC 10231. The MTT assay showed that the tested samples were not toxic and did not lead to cell death. The results showed that the essential oils used provide an effective solution as active substances in wound dressings.

Electrochemical and In Vitro Biological Evaluation of Bio-Active Coatings Deposited by Magnetron Sputtering onto Biocompatible Mg-0.8Ca Alloy
Ana-Iulia Bița, Iulian Antoniac, Marian Miculescu, George E. Stan, Lucia Leonat, Aurora Antoniac, Bujor Constantin, and Norin Forna
MDPI AG
The use of resorbable magnesium alloys in the design of implants represents a new direction in the healthcare domain. Two main research avenues are currently explored for developing or improving metallic biomaterials: (i) increase of their corrosion resistance by designed compositional and structural modifications, and (ii) functionalization of their surfaces by coating with ceramic or polymeric layers. The main objective of this work was to comparatively assess bio-functional coatings (i.e., highly-crystallized hydroxyapatite and silica-rich glass) deposited by radio-frequency magnetron sputtering (RF-MS) on a biodegradable Mg-0.8Ca alloy (0.8 wt.% of Ca). After probing their morphology (by scanning electron microscopy) and structure (by Fourier transform infrared spectroscopy and grazing incidence X-ray diffraction), the corrosion resistance of the RF-MS coated Mg-0.8Ca substrates was electrochemically tested (in synthetic biological media with different degrees of biomimicry), and their cytocompatibility was assessed in osteoblast and fibroblast cell cultures. By collective assessment, the most promising performances, in terms of mass loss (~7% after 12 days), hydrogen release rate (~6 mL/cm2 after 12 days), electrochemical corrosion parameters and cytocompatibility, were obtained for the crystalline HA coating.

Fluoride Treatment and In Vitro Corrosion Behavior of Mg‐Nd‐Y‐Zn‐Zr Alloys Type
Pham Hong Quan, Iulian Antoniac, Florin Miculescu, Aurora Antoniac, Veronica Manescu (Păltânea), Alina Robu, Ana-Iulia Bița, Marian Miculescu, Adriana Saceleanu, Alin Dănuț Bodog,et al.
MDPI AG
Fluoride conversion coatings on Mg present many advantages, among which one can find the reduction of the corrosion rate under “in vivo” or “in vitro” conditions and the promotion of the calcium phosphate deposition. Moreover, the fluoride ions released from MgF2 do not present cytotoxic effects and inhibit the biofilm formation, and thus these treated alloys are very suitable for cardiovascular stents and biodegradable orthopedic implants. In this paper, the biodegradation behavior of four new magnesium biodegradable alloys that have been developed in the laboratory conditions, before and after surface modifications by fluoride conversion (and sandblasting) coatings, are analyzed. We performed structural and surface analysis (XRD, SEM, contact angle) before and after applying different surface treatments. Furthermore, we studied the electrochemical behavior and biodegradation of all experimental samples after immersion test performed in NaCl solution. For a better evaluation, we also used LM and SEM for evaluation of the corroded samples after immersion test. The results showed an improved corrosion resistance for HF treated alloy in the NaCl solution. The chemical composition, uniformity, thickness and stability of the layers generated on the surface of the alloys significantly influence their corrosion behavior. Our study reveals that HF treatment is a beneficial way to improve the biofunctional properties required for the studied magnesium alloys to be used as biomaterials for manufacturing the orthopedic implants.

Comparative assessment of in vitro and in vivo biodegradation of Mg-1Ca magnesium alloys for orthopedic applications
Iulian Antoniac, Răzvan Adam, Ana Biță, Marian Miculescu, Octavian Trante, Ionuț Mircea Petrescu, and Mark Pogărășteanu
MDPI AG
Use of magnesium implants is a new trend in orthopedic research because it has several important properties that recommend it as an excellent resorbable biomaterial for implants. In this study, the corrosion rate and behavior of magnesium alloys during the biodegradation process were determined by in vitro assays, evolution of hydrogen release, and weight loss, and further by in vivo assays (implantation in rabbits’ bone and muscle tissue). In these tests, we also used imaging assessments and histological examination of different tissue types near explants. In our study, we analyzed the Mg-1Ca alloy and all the hypotheses regarding the toxic effects found in in vitro studies from the literature and those from this in vitro study were rejected by the data obtained by the in vivo study. Thus, the Mg-1Ca alloy represents a promising solution for orthopedic surgery at the present time, being able to find applicability in the small bones: hand or foot.

Comparative framework of calcium phosphates-based products derived from sustainable marine and terrestrial resources for biomedical applications

Adhesion evaluation of different bioceramic coatings on Mg-Ca alloys for biomedical applications
Ana-Iulia Bita, G. E. Stan, M. Niculescu, I. Ciuca, E. Vasile, and I. Antoniac
Informa UK Limited
Abstract The aim of this study was to evaluate the adhesion of different bioceramic coatings deposited by radio frequency magnetron sputtering on the biodegradable implant-type magnesium–calcium (MgCa) alloys. Hydroxyapatite (HA) and bioactive glass (BG) were chosen as coating materials, due to their remarkable biological potential. The morphology, composition, structure and adhesion of the deposited thin coatings was characterized by scanning electron microscopy, atomic force microscopy, energy dispersive X-ray spectroscopy, grazing incidence X-ray diffraction, Fourier transform infrared spectroscopy and pull-out adherence measurements. A variation of the coating-to-substrate adhesion has been recorded and correlated with the physico-chemical results. The bonding strength values of the coatings were promising (being superior to the ISO13779-2:2008 fabrication standard for load-bearing biomedical coatings), and thus, encourage us to further proceed with the biological evaluation of the HA or BG coatings-MgCa substrate couples.

Glass-ceramic coated Mg-Ca alloys for biomedical implant applications
J.V. Rau, I. Antoniac, M. Fosca, A. De Bonis, A.I. Blajan, C. Cotrut, V. Graziani, M. Curcio, A. Cricenti, M. Niculescu,et al.
Elsevier BV

In vitro degradation and corrosion evaluation of Mg-Ca alloys for biomedical applications

Influence of antibiotics addition in bone cements for hip arthroplasty on their mechanical properties: Clinical perspective and in vitro tests
Razvan Ene, Zsombor Panti, Mihai Nica, Marian Pleniceanu, Patricia Ene, Monica Cîrstoiu, Octavian Trante, Ana Iulia Bita, Aurora Antoniac, and Catalin Cirstoiu
Trans Tech Publications, Ltd.
Bone cement has been used for over half a century, to successfully anchor artificial joints. From its emergence there have appeared a number of types of bone cement, with the 2 major classes being bone cement with or without active substances. The one with the added antibiotics is used primarily in the treatment and revision surgery of infected total hip arthroplasty (THA), as well as a prophylactic method in primary THA in patients with high risks for this complication. The purpose of this study is to determine the mechanical properties of bone cement with added antibiotics. Over a period of 2 years, a number of 41 cases were chosen for this study: 25 with revision surgery for THA, where bone cement with antibiotics was used, and 16 with primary THA, where regular bone cement was used. A number of studies have been performed on the mechanical properties of the 2 types of cement, which determined that the cement with antibiotics presents a slightly lower compressive strength, tensile strength, elastic modulus and fatigue strength compared with regular cement. These variations, however, become more pronounced as the quantity of the antibiotic goes up. The mechanical properties of the cement with antibiotics are similar with those of the regular cement, when low doses of antibiotics are used and become more evident as the doses go up. In conclusion, the antibiotic bone cement is a trustworthy tool in the surgeon’s arsenal against infection, with minimal detriments from the mechanical view.

Hydrogen evolution analyzed on various magnesium alloys
Ana Iulia Bita, Augustin Semenescu, Aurora Antoniac, and Iulian Antoniac
Trans Tech Publications, Ltd.
The purpose of this study was to evaluate the biodegradability of some magnesium alloys, different both from the point of view of chemical composition and different system (Mg-Ca, Mg-Zn-Ag). Microstructural characteristics of experimental magnesium alloys were investigated using optical microscopy and scanning electron microscopy coupled with energy dispersive X-ray. The hydrogen evolution was analyzed using the method proposed by Song. The assessment was made through the evaluation of hydrogen released rate in simulated body fluid (SBF) as proposed by Kokubo and his colleagues, maintaining the temperature at 37 °C, for 240 hours. The studied samples showed different degradation rates depending on the chemical composition of magnesium based alloys and function of immersion time.

Bioceramics and biocomposites from marine sources
Iulian Vasile Antoniac, Isidoro Giorgio Lesci, Ana Iulia Blajan, Greta Vitioanu, and Aurora Antoniac
Trans Tech Publications, Ltd.
Advanced technologies and biocomplexity offer new dimensions for the development of novel medical products obtained from marine resources. Because several biomaterials can be derived from synthetic or natural sources, this area offers a very large variety of natural species that may be used for biomedical applications, including tissue engineering, drug delivery and surgery. The marine environment is a natural collector of porous materials the porosity of which varies from submicron to millimeter. The production of hydroxyapatite from synthetic chemicals can sometimes lead to a costly work and sea creatures may represent an alternative way to produce very fine and even nano-structured biomaterials. Rapana venosa is, in this sense, a study marine organism because its shell is made of aragonite that can be converted into bioceramic powder, which can subsequently be used for biomedical applications. The indirect use of marine organisms was tackled according to different routes: synthetic precursor casts using biomorphic moulds, chemical conversion of the inorganic marine matrix into a biomorphic substitute, and self-assembly of nanoparticles via chemical and molecular interactions. The chemical conversion is the most developed practice to obtain biomaterials for bone regeneration. It can be realized by hydrothermal synthesis or hydrothermal hot pressing. Both methods suppose a pre-treatment to remove the organic matrix of the skeleton. Hydrothermal synthesis involves heating the marine skeletons under alkaline conditions at a specific temperature pressure in either a reaction vessel or an autoclave. The temperature and pressure have an important significance concerning material structure properties of final product in terms of degree of crystallinity, grain size, and specific surface area. The temperature has an importance on the crystallite size (50-150 nm), and in general, the optimal temperature ranges between 200-250°C. Hydrothermal hot pressing is the process used in the fabrication of some commercial bone substitutes from coral sources and involves the solidification of synthetic hydroxyapatite powder. Some experimental results related to the processing of Rapana venosa snail shell in order to obtain hydroxyapatite for medical applications are presented at the end. In conclusion, preliminary results obtained by us show that this snail shell appears to be suitable to be used as raw material for obtaining hydroxyapatite.

Effect of calcium content on the microstructure and degradation of Mg-Ca binary alloys potentially used as orthopedic biomaterials
Ana Iulia Blajan, Florin Miculescu, Ion Ciucă, Mihai Cosmin Cotruț, Augustin Semenescu, and Iulian Vasile Antoniac
Trans Tech Publications, Ltd.
The effect of calcium addition in modifying the microstructural aspects and corrosion behavior was investigated on two different biodegradable magnesium alloys type Mg-xCa binary alloys (x = 0.8, 1.8 wt. (%)). Systematic microstructure investigations was made using optical microscopy and scanning electron microscopy coupled with energy dispersive X-ray. Following these experimental investigations, in the microstructure of the investigated Mg-Ca alloys a notable refinement was observed occurred with increasing the calcium content. The evaluation of corrosion resistance was performed both using electrochemical measurements and hydrogen release in simulated body fluid (SBF), as proposed by Kokubo and his colleagues, maintaining the temperature at 37°C. The results showed a lower corrosion resistance when the calcium content was increased, due to the increased Mg2Ca intermetallic phase in grain boundaries. Consequently, our preliminary results showed that MgCa0.8 alloy having a minimal amount of Mg2Ca appear to be a promising alloy to be used as a biomaterial for orthopedic implants.

Metallic biomaterials processing technologies in order to obtain a new design for a hip prosthesis femoral component
Marius Niculescu, Iulian Vasile Antoniac, and Ana Blajan
Trans Tech Publications, Ltd.
The paper presents the processing technology that could be used in order to obtain a new design of a stem component for a hip prosthesis type lattice beam. This new design was made based on the analysis of the currently successful stems used in clinical practice and on different biomechanical and biomaterials criteria. Metallic biomaterials used for manufacturing different components for hip prosthesis are usually austenitic stainless steel type 316L, Co-Cr alloy and titanium based alloy. In our study, considering the specific design of the stem, stainless steel type 316L with the nominal compositions (%weight): C <0.03, Cr 17, Ni 14.5, Mo 2.7, Mn <2.0, Si <1.0, P <0.025, S <0.010, Fe balance is used. Different mechanical processing techniques were used in order to obtain the experimental prototype. According to the well-known limitation of the stainless steel type 316L as biomaterial for long term implants, we propose for the new stem component to use a TiN coating obtained using magnetron sputtering technique. The cytotoxicity studies were performed using a CCl 81 (VERO) stabilized cellular line, in order to analyse the biocompatibility properties. The samples were examined for the development of the cellular culture, in order to compare the results obtained using direct contact method. From the point of view of these tests, it was not observed an essential modification of cells and the cellular morphology is not affected by the presence of the TiN coated metallic samples. In the conclusion, the new geometry proposed for a stem component of cemented hip prosthesis could be made using different mechanical processing techniques and appears to be a potential solution in order to solve the problems related to the stability of the total hip prosthesis, with improved biocompatibility properties due to the TiN coatings.

Effect on adhesion to tooth structure for some experimental dental adhesive system
Loredana Colceriu, Sanda Cimpean, Codruta Nicola, Sorina Sava, Marcela Trif, Tinca Buruiana, Marioara Moldovan, Laura Silaghi-Dumitrescu, Aurora Antoniac, Ana-Iulia Blajan,et al.
Trans Tech Publications, Ltd.
The present study was conducted with the aim of evaluating and comparing the microleakage at the dentin and enamel/composite interfaces of two adhesive systems. The adhesives are: a new-developed experimental adhesive systems and OptiBond FL (Kerr Corp.) The new adhesive system was prepared for the composite material as three steps adhesive (etchant, primer and bonding). The bonding resin contains the base monomer that was present in the corresponding composite material, HEMA and TEGDMA as diluents. Twenty box-type Class V standardized cavities were prepared on the facial and oral surfaces of each tooth, with coronal margins in enamel and apical margins in cementum (dentin). The preparations were restored with two restorative materials a new experimental microfilled resin composites based on Bis-GMA analogue and hybrid resin composite Herculite XRV Ultra (Kerr Corp.). The teeth were thermocycled and immersed in 2% methyl blue solution for 24 hours. The specimens were sectioned buccolingually into 3 slices and the resulted sections were examined using a stereomicroscope under 40x magnification. The extent of dye penetration was measured in a quantitative manner. This measurement was converted into percentage using the formula described by Sano et al.I=p/Lx100. These percentage values were submitted to variance analyses (ANOVA) andttest at a p<0.05 level of significance. Scanning electron microscopy was used in order to see the interface between tooth and composite restoration. Significantly less microleakage was associated with the use of OptiBond FL adhesive system at the enamel surface. Between the enamel and the dentin margins no significantly statistical differences were found just for the experimental adhesive system. This adhesive containing water and ethanol as solvent performed significantly better at the dentin margins.

Failure analysis of some retrieved orthopedic implants based on materials characterization
Marin Bane, Florin Miculescu, Ana Iulia Blajan, Mihaela Dinu, and Iulian Antoniac
Trans Tech Publications, Ltd.
The aim of this paper is to determine causes of failure of orthopedic implants like intramedullary nail based on explants analysis and materials characterization. The clinical performance, corrosion characteristics and metallurgical properties of some retrieved titanium femoral nails have been examined. The macroscopic and the microscopic investigation of explants help us to describe the breaking mechanism and to identify the potential causes that led to implant failure.

Ana-Iulia Bița

EDUCATION

Scopus Publications