Cristian Pirvu

Cristian Pirvu
Polytechnic University of Bucharest | UPB · Department of General Chemistry

Professor

About

108
Publications
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1,023
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Publications

Publications (108)
Article
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Due to their superior mechanical and chemical properties, titanium (Ti) and its alloys have been widely used as orthopedic implantable devices. However, their bioinertness represents a limitation, which can be overcome by employing various surface modifications, such as TiO2 nanotube (TNT) fabrication via electrochemical anodization. Anodic TNTs pr...
Article
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This research deals with the deposition of copper on a steel substrate. Two different methods were investigated: electrochemical and magnetron sputtering. The deposition parameters were optimized to obtain a coating layer with uniform granular structure and good adhesion to the substrate. As a novelty, carbon nanowalls (CNW) were used as reinforcem...
Article
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In this study, a new material obtained from titanium ingots residue was coated with natural carotenoids having antibacterial properties. The waste is a no recycling titanium scrap from technological production process which was pressed and transformed into disks titanium samples. Through anodization and annealing procedures of the titanium disk, a...
Article
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The aim of the current paper is the development of phytosynthesized silver nanoparticles mediated by Raphanus sativus L. extracts obtained through two extraction methods (temperature and microwave) and to test their potential application for controlling apple crops pathogens. The phytosynthesized materials were characterized by X-ray diffraction, s...
Article
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The present paper presents a gliadin detection method. This method is based on a modified Ti electrode. Modification was performed by a simple and cheap anodization. Then, a layer of graphene oxide was added, and gliadin antibody was fixed on the electrode surface. Using this complex system, electrochemical impedance spectroscopy was used for gliad...
Article
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A new thiosemicarbazone ligand was immobilized through a Cu(I)-catalyzed click reaction on the surface of glassy carbon (GC) and electrochemically reduced graphene oxide (GC-ERGO) electrodes grafted with phenylethynyl groups. Using the accumulation at open circuit followed by anodic stripping voltammetry, the modified electrodes showed a significan...
Cover Page
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REVISTA DE CHIMIE Cite as: Rev. Chim. https://doi.org/10.37358/Rev.Chim.1949 OSIM Nr. R102355 ISSN Print 0034-7752 ISSN Online 2668-8212 Journal Metrics * Impact Factor 2019: 1.755 * 5-Year IF: 1.351 * CiteScore: 2.2 * H index: 28 (InCites Journal Citation Reports) Revista de Chimie REVISTA DE CHIMIE Revista de Chimie is internationally rec...
Article
Celiac disease (CD) is an autoimmune disorder. For these patients, the only treatment is a gluten free diet. In this work we showed that there can be an easy and cheap method to test gluten presence. We used several modified Ti electrodes. All modified electrodes were prepared using electrochemical methods. Modified electrodes were tested using dif...
Article
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This study proposes the development of new architectures that combine nanostructured titanium surface and biodegradable polymers as a promising approach to achieve a better performance after bioactive agent incorporation. The silk fibroin protein that was extracted from silkworm Bombyx mori cocoons is important due to the remarkable characteristics...
Article
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Despite many discussions about Ti versus Zr, Ti remains the golden standard for dental implants. With the extended use of implants, their rejection in peri-implantitis due to material properties is going to be an important part of oral health problems. Extended use of implants leading to a statistical increase in implant rejection associated with p...
Article
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The aim of this study was the valorization of titanium flakes (waste) from titanium and titanium alloy ingot production factories and using in applications related to metals recovery as retention bed for some trace metals. The titanium flakes were anodized for surface nanostructuration with TiO2 nanotubes and then annealed in order to increase the...
Article
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An integrated system for photo-accumulation (photoreduction) and sensing, based on a Zr/ZrO2 electrode, has been developed for the detection of trace heavy metals. The nanostructuring of the Zr/ZrO2 electrode was achieved by anodizing, which produced a nanotubular structure. Solutions containing Cd(II), Pb(II), Cu(II) and Hg(II) were used for analy...
Article
The paper describes an innovative bio-design of some hybrid nanoarchitectures containing bioartificial membranes and silver nanoparticles phytogenerated by using a natural extract Caryophyllus aromaticus (cloves) that contains many bioactive compounds. Two kinds of liposomes with and without chlorophyll a (Chla) obtained through thin film hydration...
Article
The aim of this paper was to present a parallel investigation of the poly(dopamine) (DP) and nitrodopamine (NDP) structures deposited on titanium surface (Ti) and titanium oxide nanotubes (NT-TiO2/Ti) and to highlight their advantages and drawbacks to serve as an intermediary layer for bone regeneration applications. This study outlines some hypoth...
Article
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The combined influence of iron and calcium salts can increase the voltage and power of MFC systems using Saccharomyces cerevisiae as biocatalyst, but no systematic studies were performed. To explore these incomplete understood interactions, the production of bioelectricity has been studied in two types of dual-chambered MFC systems: in small volume...
Article
We report hereby the results of our study on optical damage threshold of DNA and DNA-CTMA thin films, doped with natural chromophores extracts. The films were obtained by spin coating on glass substrates. Their morphology was studied by scanning electron microscopy. Their optical damage threshold, which is an important parameter determining practic...
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Based on previously reported findings showing reduced foreign body reactions on nanochannelar topography formed on TiZr alloy, this study explores the in vitro effects of such a nanostructured surface on cells relevant for implant osseointegration, namely osteoblasts and osteoclasts. We show that such nanochannelar surfaces sustain adhesion and pro...
Article
TiO2 nanowires are fabricated by electrospinning on Ti50Zr alloy, by changing the elaboration conditions. The surface covered with nanowires is characterized by performing scanning electronic microscopy and contact angle measurements. The best surface from the point of view of nanowires organization is chosen based on experimental conditions. The e...
Article
The present paper introduces a study on the preparation and characterization of cellulose acetate – TiO2 nanotubes membrane. In order to be used as a hemodialysis membrane, fraxiparinized nanotubes have been incorporated into the cellulose matrix. Fraxiparine embedding was performed via strong binding ability of dopamine. Composite membrane was cha...
Article
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In recent years, a considerable interest was paid to ecological strategies in management of plant diseases and plant growth. Metallic nanoparticles (MNPs) gained considerable interest as alternative to pesticides due to their interesting properties. Green synthesis of MNPs using plant extracts is very advantageous taking into account the fact that...
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This paper presents some physical and mechanical properties of Portland cement mortars prepared with two types of waste as alternative aggregates. These wastes result during the mechanical processing of titanium alloy ingots by shot blasting with steel beads (DS) or by surface abrasion/polishing process with abrasive discs (DSIC). The total replace...
Article
A simple bottom-up strategy was used to achieve biocomposites designed from carbon nanotubes decorated with chlorophyll a – loaded biomimetic membranes. The emission fluorescence of chlorophyll a was exploited for monitoring insertion of quercetin in these biohybrids. Morphological aspects of the samples were revealed by AFM analysis. The bio-based...
Article
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This study has been carried out to investigate a new method to improve metallic implant bioactivity for osseointegration by producing a calcium phosphate (Ca-P) surface layer using an immersion process in the Simulated Body Fluid (SBF) of Polypyrrole (PPy) and Polypyrrole/poly(sodium-4styrensulfonate) (NaPSS) conductive hybrid polymers electrochemi...
Article
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Cerium oxide nanoparticles (CeO 2 NPs) in crystalline form have been synthesized by a coprecipitation method. CeO 2 nanoparticles were then embedded in polypyrrole (PPy) films during the electropolymerization of pyrrole (Py) on titanium substrate. The influence of poly(sodium 4-styrenesulfonate) (NaPSS) surfactant used during polymerization on the...
Article
Novel nanohybrids consisting of nano-Ag, chitosan, lipids and phyto-compounds (chlorophyll a and curcumin) have been achieved through a simple bottom-up strategy, resulting in stable (ZP = − 30.9 mV) and spherical-shaped nano-entities with size < 200 nm (estimated by AFM analysis and DLS measurements). The formation of these biohybrids was monitore...
Article
In a Surface Plasmon Resonance (SPR) experiment two key parameters are classically recorded: the time and the angle of SPR reflectivity. This paper brings into focus a third key parameter: SPR reflectivity. The SPR reflectivity is proved to be related to surface roughness changes. Practical investigations on (i) gold anodizing and (ii) polypyrrole...
Article
Electrochemical and Surface Plasmon Resonance (SPR) experiments are made in ultrapure water at ultralow concentrations of phenol. SPR technique has been proved to be complementary to the electrochemical technique in the study of surface adsorption/desorption and phenol polymerization process.
Conference Paper
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In the last years, microbial fuel cells (MFCs) have emerged like a novel research technologies for production of sustainable and clean electricity energy through bioxidation of organic materials, representing a promising alternative to combustion energy sources. In this study, production of bioelectricity in MFC in batch system (dual chambered MFC)...
Article
In dentistry, one of the major problems is related to the adherence of the composite filling materials to the dentin. Presently, in order to enhance this adherence, different adhesive materials are used. The main cause for the filling failure is the marginal degradation appeared between the filling material and the dentin, due to the weak structure...
Article
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A new dye-sensitized solar cell (DSSC) counter electrode was obtained through the electropolymerization of the monomer 3.4-Ethylendioxythiophene (EDOT) directly onto a indium tin oxide (ITO) coated glass in the presence of an aqueous titania nanotubes (TiO2NTs) suspension. The TiO2nanotubes in the anatase phase were incorporated in the conductive p...
Article
In this article, the corrosion processes that occur in metallic fixed dental restorations from a group of patients with oral lichen planus are investigated throughout electrochemical characterizations. Oral lichen planus (OLP) is a non-infectious, chronic, autoimmune disorder, of unknown aetiology, which involves the oral mucosa and sometimes, it h...
Article
Lanthanide ions have attracted intense research interest for their luminescence properties, which make them interesting for applications such as bioactive probes for magnetic resonance and luminescence. We present here our study related to the interaction between DNA–CTMA (hexadecyltrimethylammonium chloride) and praseodymium. The new materials syn...
Article
This paper describes an original bio-design of organic/inorganic hybrid architectures containing biomimetic membranes and celandine–nanoAg for different bioapplications. A simple, time efficient, low-cost and ecofriendly bottom-up procedure was used to build for the first time, celandine/nanoAg-based hybrids. Dipalmitoyl phosphatidylcholine bio-ins...
Article
Implant-associated infections are a major cause of morbidity and mortality. This study was performed using titanium samples coated by anodization with a titanium dioxide (TiO2) shielded nanotube layer. TiO2/Ti surface was modified by simple immersion in torularhodin solution and by using a mussel-inspired method based on polydopamine as bio adhesiv...
Article
Ti surface was modified with a natural antioxidant and antimicrobial agent, torularhodin, by its incorporation onto a Ti/TiO2 substrate via anodization process. This natural antioxidant and antimicrobial agent can be produced from waste materials, as an alternative to synthetic antimicrobial compounds. Scanning electron microscopy (SEM), Structura...
Article
Using easy and cheap potential step anodization in electrolytes with different molar mass and watercontent, a Ti substrate was covered with a nanostructured TiO2layer. Surface characterization of theprepared samples was conducted using scanning electron microscopy (SEM), Fourier transform infraredspectroscopy (FT-IR) and contact angle analysis. The...
Article
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Nanotubular and nanochannels structures were fabricated via anodizing on a new alloy Ti-20Zr-8Ta-2Ag. A continuous coating of connected tubes/channels can be observed in the SEM micrographs forming tubular structures with diameters in hundreds of nm, as well as smaller tubes, with diameters in tens of nm. In the case of nanochannels structure, the...
Article
In this paper we report conformational changes recorded on a protein molecule (alpha-amylase) under green light irradiation. In order to explain the experimental results we advanced the hypothesis that green light induces electric dipoles in the protein, which interact with each other, generating conformational modifications toward a more compact d...
Article
The paper aims on the investigations of corrosion processes of three different porcelain fused to metal dental crowns with CoCrMo frameworks. The three crowns, with different exposed metal surfaces, were investigated using electrochemical impedance spectroscopy (EIS), through 168 hours of experiment. The data were analyzed and the influence of corr...
Article
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The Surface Plasmon Resonance (SPR) is a technique well established as a highly sensitive biosensing tool. This work expanded the use of the SPR by the realtime monitoring of the pyrrole electropolymerization, thus obtaining an intrinsically conductive polymer. The high sensitivity of SPR indicates a specific range in which accurate measurements ca...
Article
The paper aims on microfabrication and corrosion processes evaluation of three different metal-ceramic crowns with CoCrMo substructures. The samples have different exposed metal surface and the electrochemical investigations are Tafel analysis and Electrochemical Impedance Spectroscopy (EIS).
Article
By mixing the same concentration polyethylene glycol (PEG) with molar masses of 400, 600 and 1000, a series of poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT: PSS) composite thin films were prepared by spin coating. The morphology of the films was inspected by Atomic Force Microscopy (AFM). Electrochemical characterizations perfor...
Article
The Gigahertz Resonance at a gold nano-layer, coupled with an Electrochemical system allowed the investigation of the interfacial interaction of ions at the gold/aqueous solution boundary. The implications of the ion behavior under polarized electric fields are discussed. The study of non-Faradaic and Faradaic currents open the path for increased v...
Article
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The purpose of this study was to investigate the effect of ultrasonic scaling on teeth restored with a light-cured resin. Ultrasonic scaling is a very popular periodontal therapy among dentists, and used for the removal of dental plaque and calculus in order to reduce and eliminate inflammation. Given the fact that most ultrasonic devices are used...
Article
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AbstractThe practice of dentistry involves laborious high finesse dental preparations, precision and control in executions that require a particular attention, concentration and patience of the dentist and finally the dentist’s physical and mental resistance. The optimal therapeutic approach and the success of practice involve special working condi...
Article
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The paper's aim is to evaluate the corrosion behaviour for the TiO 2 oxide film native and obtained using laser texturing procedure. The chosen working conditions lead to grooves on treated sample which can be used to increase the bone implants strength. A better cell viability was observed after 24 h, but for longer period of time (48 h) was decre...
Article
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The main objective of the current paper is to show that electrochemical impedance spectroscopy (EIS) could be a method for evaluating and predicting of ProTaper rotary file system clinical lifespan. This particular aspect of everyday use of the endodontic files is of great importance in each dental practice and has profound clinical implications. T...
Article
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Fluoride under various forms is one of the most used substances in dentistry and prevention. It is a joined effort of many countries to incorporate fluoride in water, salt and many other consumer products but could it be too much? Modern day dentistry struggles to offer the possibility of tooth whitening to any nuance with no pain at all. Some prod...
Article
The paper is focused on using the electrochemical impedance spectroscopy (EIS) technique for enhancing cleaning and disinfecting of the root canal structure. The research investigated both NaOCl and EDTA (ethylenediaminetetraacetic acid) effects, establishing the optimal time of EDTA (ethylenediaminetetraacetic acid) application.
Article
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In this study, polypyrrole (PPy) films were successfully synthesized on Ti6Al7Nb alloy by potentiostatic polymerization in the presence of poly(sodium 4-styrenesulfonate) (NaPSS), t-octylphenoxy polyethoxyethanol (Triton X-100) and N-dodecyl-β-D-maltoside (DM) surfactants. Atomic force microscopy (AFM) analysis of the PPy/surfactant composite films...
Article
in this work, three different techniques are presented that deal with the formation of the TiO,films on titanium by metal organic chemical vapor deposition (MOCVD), electrochemical anodization and laser treatment. These techniques have some advantages in the growth stages, and produce films with different properties which recommend them for specifi...
Article
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The effects of electrolyte type used in electrodeposition of polypyrrole (PPy) films on Ti6Al7Nb alloy was studied in order to design a titanium modified surface with enhanced antibacterial activity and better biocompatibility. Therefore, the polypyrrole coatings were synthesized by potentiostatic electrochemically technique from pyrrole and lithiu...
Article
Recurrent post-treatment endodontic infection is a frequent issue in today's dental practice. Our study presents a complex investigation on the formation of the acquired protein pellicle, a natural forming intraoral biostructure offering a novel approach in understanding this natural process. The dental pellicle can form on any structure of the ora...
Article
This paper presents the results regarding characterization and protective properties of a new organic coating with low content of volatile organic compounds based on acryl resin. The coating was applied on carbon steel substrate and realized from a single layer (30-35 mm) and two layers (55-60 mm). The electrochemical techniques (electrochemical im...
Article
Phenols are well known as a class of pollutants that have a fouling effect on the electrode during electrochemical detection.The paper focuses on the investigation of the antifouling ability of Au/PPy and Au/PPy/PSS modified electrodes, during phenols electro-oxidation by electrochemical surface plasmon resonance technique (ESPR).The PPy and PPy/PS...
Article
The present paper reports on the formation and respectively shielding of TiO2 nanotubes elaborated in two water-containing organic electrolytes with the addition of NH4F, via potential step anodizing method. The organic compounds used ethylene glycol (EG) and polyethylene glycol (PEG), have significantly different molecular weights and viscosities....
Article
The formation process of auto-organised titanium oxide nanotube structures is presented using the electrochemical atomic force microscopy (EC-AFM). The images recorded in real time during the formation process of the auto-organised titanium oxide structures in two electrolytes, one inorganic and one hybrid organicinorganic highlighted differences i...
Article
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In order to enhance properties of the polymer composite films, composite coatings based on polypyrrole (PPy) and polyethylene glycol (PEG), using various percentages of PEG (0.5%, 2%, 4%), were electrodeposited on a new titanium alloy electrode as insulating material. The structure of the coatings was investigated via infrared (FTIR) analysis, and...
Article
The paper is a study about titanium surface modification with TiO2 nanotubes elaborated in viscous organic electrolyte, PEG 600, with small water amount and NH4F, also about possibility to remove of created shielding layer TiO2 – PEG, with ultrasound treatment. The self-organized nanostructures were characterized during ultrasound treatment by elec...
Article
Self-adhesive cements are the lmost recent class of cements based on resin composites designed to secure the prosthetic restorations to dental tissues. Comparatively to classic cements based on resins, they are more attractive to dentists because there is no requirement for a preconditioning of the substrates. Nevertheless, their adhesive performan...
Article
Electrochemical monitoring of electrical and structural changes of both PPy and PPy–PEG films electrochemical deposited, in order to highlight if the structural stability offered by PEG has an influence on electrical properties and stability in aqueous solution over immersion time was investigated.Electrochemical analysis suggests that PPy–PEG film...