Full Length ArticleCopper nanoparticles obtained by laser ablation in liquids as bactericidal agent for dental applications
Graphical abstract
Introduction
Nowadays, more and more infections caused by resistant microorganism, fail to conventional treatments. According to the Centre for Disease Control and Prevention (CDC), antibiotic resistant bacteria cause at least 2 million infections per year with 23,000 deaths in the U.S. and 25,000 deaths in Europe [1]. The excess and improper use of antibiotics, has made the treatment of infections more difficult and expensive; some voices in the health system claim we are facing a new global health crisis [2], [3]. In this sense, Gram-negative bacteria are a huge threat, because of the rapid evolution of their resistance mechanisms what results in insusceptibility to nearly all available antibiotics [4].
In dentistry, some of the more extended diseases caused by bacterial infections are periodontitis and periimplantitis. In both cases, the inflammation and destruction of soft and hard tissues surrounding teeth or dental implants, ultimately leads to loss of teeth or dental implant failure as the most common consequences [5]. Although many risk factors are related to the origin of periimplantitis [6], pathogenic microflora are the main cause of this periodontal disease [5]. Aggregatibacter actinomycetemcomitans is a Gram-negative bacteria and commonly part of the normal flora of human mouths, especially in gingival and supragingival crevices [7].
In light of this situation, it is necessary to explore new alternatives in the treatment of diseases caused by infections such as periimplantitis. Nobel metal nanoparticles have become an attractive alternative source to fight against such resistant microorganisms. The antibacterial activity of noble metal nanoparticles have been extensively studied because of their high surface to volume ratio, that increases reactivity allowing to kill the pathogens efficiently [8]. Particularly, copper nanoparticles are of special interest because they are potentially effective against different bacterial pathogens [8], [9], and are very attractive in terms of cost when compared for example with Ag nanoparticles [10].
Although a great number of studies in the recent years have tried to explain the mechanisms of the bactericidal process, this still represents a gap in our knowledge. Previous researches have addressed that not only the size is behind this remarkable antibacterial activity, also shape and crystallographic structure of the nanoparticles [11], which depend on the fabrication method. In this sense, Laser ablation of solids in liquids (LASL) is a key technique to obtain pure nanoparticles with no need of chemical precursors which can contaminate the obtained material, resulting in a potential harmful agent not only for the target bacteria but also for the healthy tissues.
In previous works, other noble metal nanoparticles such as Ag NPs were obtained by means of laser ablation in open air [12] and water [13], [14] and their bactericidal effects were demonstrated. Copper and copper oxide nanoparticles were already synthesized by laser ablation in different solvents such as distilled de-ionized water [15], acetone [16] or organic solutions such as phenanthroline [17]. These works show that the characteristic features of the obtained nanoparticles can be controlled by varying the laser parameters and the liquid properties. Although all of them demonstrate the bactericidal properties of copper nanoparticles, none of them establishes the relationship between bactericidal activity and physicochemical properties, neither their biocompatibility.
In the present work, the bactericidal properties of the Cu nanoparticles are evaluated against A. actinomycetemcomitans (a Gram negative bacteria) one of the main pathogens responsible for inducing localized aggressive periodontitis [18], peri-implantitis [5] and various non-oral infections [7]. In order to assess their biocompatibility, the cytotoxic effects were evaluated using human periodontal ligament stem cells. The mechanism responsible for the bacterial growth inhibition is also studied and discussed. The present study provides some insights as to the influence of nanoparticle size, morphology, oxidation state, crystallographic structure, stability and ion release on the biocidal process.
Section snippets
Laser ablation
Copper foils with 99.99% of purity (Thermo Fisher Scientific), were used as laser ablation targets. In order to analyze the influence of the laser parameters and the liquid medium used in the process, the targets were submerged in two different solvents and ablated by two different diode-pumped Nd:YVO4 laser sources.
Sample nomenclature with the corresponding assay conditions are listed in Table 1.
The first laser source was a nanosecond laser providing pulses at wavelength of 532 nm (Green –
Results and discussion
Cu-NPs in suspension were produced by laser ablation in two different solvents without using any chemical precursors. Nanoparticle formation was directly detected because of the change in the solvent color, from colorless to the final coloring (see Fig. 2). The colloidal solutions obtained in water (a and c) exhibit greenish color indicating oxidized Cu. The nanoparticles obtained in methanol show lighter color due different level of oxidation and particle size.
Despite the different color of
Conclusions
Feasibility of laser ablation of solids in liquids to produce crystalline copper nanoparticles without any additional chemical compound is demonstrated. The type of solvent has more influence over size and stability of the obtained nanoparticles than the laser source used and determines to a large extent the characteristics of the nanoparticles.
Cu-NPs obtained by laser ablation in methyl alcohol are spherical with low degree of oxidation, while those obtained in water present chain-like
Author Contributions
M. Fernández-Arias: Collected the data, Performed the analysis, Wrote the paper. M. Boutinguiza: Conceived and designed the analysis, Performed the analysis, Wrote the paper. J. Del Val: Contributed data or analysis tools, Other contribution: Graphic design. C. Covarrubias: Conceived and designed the analysis, Collected the data. F. Bastias: Contributed data or analysis tools. L. Gómez: Performed the analysis. M. Maureira: Collected the data. F. Arias-González: Contributed data or analysis
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This work was partially supported by the EU research project Bluehuman (EAPA_151/2016 Interreg Atlantic Area), Government of Spain [RTI2018-095490-J-I00 (MCIU/AEI/FEDER, UE)], and by Xunta de Galicia (ED431B 2016/042, ED481D 2017/010, ED481B 2016/047-0). The technical staff from CACTI (University of Vigo) is gratefully acknowledged. C. Covarrubias acknowledges support from Project U-Redes NanoBioMat, University of Chile.
References (42)
- et al.
Infections by multidrug-resistant Gram-negative Bacteria: what’s new in our arsenal and what’s in the pipeline?
Int. J. Antimicrob. Agents.
(2019) - et al.
Synthesis of copper nanoparticles and role of pH on particle size control
Mater. Today Proc.
(2016) - et al.
Synthesis and deposition of silver nanoparticles on cp Ti by laser ablation in open air for antibacterial effect in dental implants
Mater. Lett.
(2018) - et al.
RE-irradiation of silver nanoparticles obtained by laser ablation in water and assessment of their antibacterial effect
Appl. Surf. Sci.
(2019) - et al.
In situ preparation and osteogenic properties of bionanocomposite scaffolds based on aliphatic polyurethane and bioactive glass nanoparticles
Mater. Sci. Eng. C
(2019) Laser ablation in liquids: applications in the synthesis of nanocrystals
Prog. Mater. Sci.
(2007)- et al.
Thermal conductivity measurement of methanol-based nanofluids with Al2O3 and SiO2 nanoparticles
Int. J. Heat Mass Transf.
(2012) - et al.
Preparation of silver nanoparticles by laser ablation in solution: influence of laser wavelength on particle size.pdf
Appl. Surf. Sci.
(2002) - et al.
Chitosan capped copper oxide/copper nanoparticles encapsulated microbial resistant nanocomposite films
Int. J. Biol. Macromol.
(2019) - et al.
Synthesis and characterization of Cu @ Cu 2 O core shell nanoparticles prepared in seaweed Kappaphycus alvarezii media
Int. J. Electrochem. Sci.
(2014)
Highly dispersed CuO nanoparticles prepared by a novel quick-precipitation method
Mater. Lett.
Green synthesis of copper oxide nanoparticles and its effective applications in Biginelli reaction, BTB photodegradation and antibacterial activity
Adv. Powder Technol.
Physico-chemical properties of Pd nanoparticles produced by Pulsed Laser Ablation in different organic solvents
Appl. Surf. Sci.
DLS and zeta potential – what they are and what they are not?
J. Control. Release
Influence of metal oxide nanoparticles concentration on their zeta potential
J. Colloid Interface Sci.
Bacteria antibiotic resistance: new challenges and opportunities for implant-associated orthopaedic infections
J. Orthop. Res.
The antibiotic resistance crisis Part 1: causes and threats
P&T
Metal oxide nanoparticles as antimicrobial agents: a promise for the future
Int. J. Antimicrob. Agents.
Comparative biology of chronic and aggressive periodontitis vs. peri-implantitis
Periodontol
The Peri-Implantitis : Implant Surfaces, Microstructure, and Physicochemical Aspects
Clin. Implant Dent. Relat. Res.
181 – Other Gram-Negative Coccobacilli
Cited by (44)
Cu metal nanoparticles in transparent electrodes for light harvesting in solar cells
2024, Applied Surface ScienceFast and easy synthesis of silver, copper, and bimetallic nanoparticles on cellulose paper assisted by ultrasound
2023, Ultrasonics SonochemistryOne-step synthesis of low-dimensional copper-based nanomaterials with intrinsic antioxidant properties
2023, Materials Today CommunicationsTemperature controlled morphology transformation during aging of colloidal copper nanoparticles produced by laser ablation in water
2023, Materials Today CommunicationsTailored CuCl<inf>2</inf> nanoparticles for glutamine and ammonia biochemical sensing applications
2023, Solid State SciencesCustomization of structure, morphology and optical characteristics of silver and copper nanoparticles: Role of laser fluence tuning
2023, Applied Surface ScienceCitation Excerpt :Hence, PLAL emerged as an effective and reproducible technique for the synthesis of high quality NPs advantages for applications [15,20,24]. On top, the amount of colloidal NPs dispersed in the liquid media strongly depend on various laser parameters of the PLAL method such as repetition rate, irradiance, electronegativity of the medium, experimental geometry, target morphology, focusing condition (spot size and separation of the laser source from the target), fluence, wavelength, and so forth [32–34]. Compared to the conventional methods for the synthesis of NPs, PLAL technique has more advantages due to its simplicity, low cost, environmental friendliness, flexibility to diverse metals and solvents, reproducibility, non-requirement of any chemical precursors and ability to produce high purity NPs with desirable structures and morphology in a customized way [29,35].