1
|
Sun J, Fang W, Liza AA, Gao R, Song J, Guo J, Rojas OJ. Photoluminescent Nanocellulosic Film for Selective Hg 2+ Ion Detection. Polymers (Basel) 2024; 16:1583. [PMID: 38891529 PMCID: PMC11174859 DOI: 10.3390/polym16111583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/24/2024] [Accepted: 05/27/2024] [Indexed: 06/21/2024] Open
Abstract
We developed a highly sensitive solid-state sensor for mercury detection by stabilizing red-sub-nanometric fluorescent gold nanoclusters (AuNC, 0.9 ± 0.1 nm diameter) with bovine serum albumin in a matrix composed of cellulose nanofibrils (CNF) (BSA-AuNC/CNF). The main morphological and optical features of the system were investigated via atomic force/transmission electron microscopy and UV-Vis/fluorescence spectroscopy. The hybrid film (off-white and highly transparent) showed strong photoluminescene under UV irradiation. The latter is assigned to the AuNC, which also increase the ductility of the emitting film, which was demonstrated for high sensitivity Hg2+ detection. When used as a sensor system, following AuNC printing on CNF hybrid films, a limit of detection <10 nM was confirmed. What is more, nanocellulose films have a high pore structure and selective separation properties, showcasing a wide range of potential applications in many fields such as water treatment and oil-water separation.
Collapse
Affiliation(s)
- Jing Sun
- Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources and International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China; (J.S.); (A.A.L.); (R.G.); (J.S.)
| | - Wenwen Fang
- Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16300, 00076 Helsinki, Finland;
| | - Afroza Akter Liza
- Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources and International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China; (J.S.); (A.A.L.); (R.G.); (J.S.)
| | - Rui Gao
- Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources and International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China; (J.S.); (A.A.L.); (R.G.); (J.S.)
| | - Junlong Song
- Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources and International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China; (J.S.); (A.A.L.); (R.G.); (J.S.)
| | - Jiaqi Guo
- Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources and International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China; (J.S.); (A.A.L.); (R.G.); (J.S.)
| | - Orlando J. Rojas
- Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16300, 00076 Helsinki, Finland;
- Bioproducts Institute, Department of Chemical and Biological Engineering, Department of Chemistry and Department of Wood Science, University of British Columbia, 2360, East Mall, Vancouver, BC V6T 1Z3, Canada
| |
Collapse
|
2
|
Petersen E, Barrios AC, Bjorkland R, Goodwin DG, Li J, Waissi G, Henry T. Evaluation of bioaccumulation of nanoplastics, carbon nanotubes, fullerenes, and graphene family materials. ENVIRONMENT INTERNATIONAL 2023; 173:107650. [PMID: 36848829 DOI: 10.1016/j.envint.2022.107650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/15/2022] [Accepted: 11/19/2022] [Indexed: 06/18/2023]
Abstract
Bioaccumulation is a key factor in understanding the potential ecotoxicity of substances. While there are well-developed models and methods to evaluate bioaccumulation of dissolved organic and inorganic substances, it is substantially more challenging to assess bioaccumulation of particulate contaminants such as engineered carbon nanomaterials (CNMs; carbon nanotubes (CNTs), graphene family nanomaterials (GFNs), and fullerenes) and nanoplastics. In this study, the methods used to evaluate bioaccumulation of different CNMs and nanoplastics are critically reviewed. In plant studies, uptake of CNMs and nanoplastics into the roots and stems was observed. For multicellular organisms other than plants, absorbance across epithelial surfaces was typically limited. Biomagnification was not observed for CNTs and GFNs but were observed for nanoplastics in some studies. However, the reported absorption in many nanoplastic studies may be a consequence of an experimental artifact, namely release of the fluorescent probe from the plastic particles and subsequent uptake. We identify that additional work is needed to develop analytical methods to provide robust, orthogonal methods that can measure unlabeled (e.g., without isotopic or fluorescent labels) CNMs and nanoplastics.
Collapse
Affiliation(s)
- Elijah Petersen
- Biosystems and Biomaterials Division, NIST, Gaithersburg, MD 20899, United States.
| | - Ana C Barrios
- Biosystems and Biomaterials Division, NIST, Gaithersburg, MD 20899, United States
| | | | - David G Goodwin
- Engineering Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, United States
| | - Jennifer Li
- Biosystems and Biomaterials Division, NIST, Gaithersburg, MD 20899, United States
| | - Greta Waissi
- University of Eastern Finland, School of Pharmacy, POB 1627 70211, Kuopio, Finland
| | - Theodore Henry
- Institute of Life and Earth Sciences, School of Energy, Geoscience, Infrastructure and Society, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| |
Collapse
|
3
|
Review on Hybrid Reinforced Polymer Matrix Composites with Nanocellulose, Nanomaterials, and Other Fibers. Polymers (Basel) 2023; 15:polym15040984. [PMID: 36850267 PMCID: PMC9959991 DOI: 10.3390/polym15040984] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/27/2023] [Accepted: 01/29/2023] [Indexed: 02/18/2023] Open
Abstract
The use of composite materials has seen many new innovations for a large variety of applications. The area of reinforcement in composites is also rapidly evolving with many new discoveries, including the use of hybrid fibers, sustainable materials, and nanocellulose. In this review, studies on hybrid fiber reinforcement, the use of nanocellulose, the use of nanocellulose in hybrid forms, the use of nanocellulose with other nanomaterials, the applications of these materials, and finally, the challenges and opportunities (including safety issues) of their use are thoroughly discussed. This review will point out new prospects for the composite materials world, enabling the use of nano- and micron-sized materials together and creating value-added products at the industrial scale. Furthermore, the use of hybrid structures consisting of two different nano-materials creates many novel solutions for applications in electronics and sensors.
Collapse
|
4
|
Cui SM, Hashmi S, Li WQ, Handschuh-Wang S, Zhu CT, Wang SC, Yang PP, Huang YF, Zhu GM, Stadler FJ. Influence of Cellulose Nanofibers on the Behavior of Pickering Emulsions. Part 1. Microscopy and Startup Flow Test. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8285. [PMID: 36499785 PMCID: PMC9736908 DOI: 10.3390/ma15238285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 06/17/2023]
Abstract
The dispersibility of flexible polymer chains present at the emulsion's interface between the dispersed and continuous phase has obvious effects on rheology and dielectric properties of the whole emulsion. Cellulose nanofiber (CNF)-based Pickering emulsions are good systems to research these properties with respect to their microscopic phase structure, dielectric, and rheological properties by using CNF as a water-dispersible Pickering emulsifier, liquid paraffin as an oil phase, and didodecyldimethylammonium bromide (DDAB) as a cationic auxiliary surfactant. The CNF and DDAB contents were systematically varied while the water-to-paraffin oil ratio was kept constant to discern the influence of the Pickering emulsifiers. Polarized optical microscopic images reveal that the droplets tend to shrink at higher CNF content but grow bigger when increasing the DDAB content, which is proved by fluorescence analysis of the CNF dispersibility with varying DDAB content. The dielectric damping exhibits a minimum, whose value decreases with increasing DDAB and CNF content. Increasing the DDAB content promotes the solubilization of CNF in the aqueous phase, which will increase the overall viscosity and yield points. Similarly, a higher CNF content leads to a higher viscosity and yield point, but at high DDAB contents, the viscosity function exhibits an S-shape at intermediate CNF contents. To evaluate the results further, they were compared with CNF dispersions (without oil phase), which showed a surfactant effect slightly on maximum stress but strongly on yield stress τy, indicating that DDAB can promote the formation of a CNF network rather than the viscosity of the whole system. This paper provides information on how a systematical variation of the composition influences morphology and physico-chemical interactions as detected by broadband dielectric spectroscopy and rheological behavior.
Collapse
Affiliation(s)
- Shu-Ming Cui
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, Nanshan District Key Laboratory for Biopolymers and Safety Evaluation, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
- South China Advanced Institute for Soft Matter Science and Technology, School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Saud Hashmi
- Department of Polymer & Petrochemical Engineering, NED University of Engineering & Technology, Karachi 75270, Sindh, Pakistan
| | - Wen-Qiang Li
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, Nanshan District Key Laboratory for Biopolymers and Safety Evaluation, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
| | - Stephan Handschuh-Wang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Cheng-Tian Zhu
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, Nanshan District Key Laboratory for Biopolymers and Safety Evaluation, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
| | - Shi-Chang Wang
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, Nanshan District Key Laboratory for Biopolymers and Safety Evaluation, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
| | - Pian-Pian Yang
- College of Management, Shenzhen University, Shenzhen 518055, China
| | - Yan-Fei Huang
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, Nanshan District Key Laboratory for Biopolymers and Safety Evaluation, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
| | - Guang-Ming Zhu
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, Nanshan District Key Laboratory for Biopolymers and Safety Evaluation, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
| | - Florian J. Stadler
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, Nanshan District Key Laboratory for Biopolymers and Safety Evaluation, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
| |
Collapse
|
5
|
Melnikov P, Bobrov A, Marfin Y. On the Use of Polymer-Based Composites for the Creation of Optical Sensors: A Review. Polymers (Basel) 2022; 14:polym14204448. [PMID: 36298026 PMCID: PMC9611646 DOI: 10.3390/polym14204448] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/08/2022] [Accepted: 10/17/2022] [Indexed: 11/16/2022] Open
Abstract
Polymers are widely used in many areas, but often their individual properties are not sufficient for use in certain applications. One of the solutions is the creation of polymer-based composites and nanocomposites. In such materials, in order to improve their properties, nanoscale particles (at least in one dimension) are dispersed in the polymer matrix. These properties include increased mechanical strength and durability, the ability to create a developed inner surface, adjustable thermal and electrical conductivity, and many others. The materials created can have a wide range of applications, such as biomimetic materials and technologies, smart materials, renewable energy sources, packaging, etc. This article reviews the usage of composites as a matrix for the optical sensors and biosensors. It highlights several methods that have been used to enhance performance and properties by optimizing the filler. It shows the main methods of combining indicator dyes with the material of the sensor matrix. Furthermore, the role of co-fillers or a hybrid filler in a polymer composite system is discussed, revealing the great potential and prospect of such matrixes in the field of fine properties tuning for advanced applications.
Collapse
Affiliation(s)
- Pavel Melnikov
- M. V. Lomonosov Institute of Fine Chemical Technologies, MIREA—Russian Technological University, 119571 Moscow, Russia
- Correspondence:
| | - Alexander Bobrov
- Department of Inorganic Chemistry, Ivanovo State University of Chemistry and Technology, Sheremetevsky pr., 10, 153010 Ivanovo, Russia
| | - Yuriy Marfin
- Department of Inorganic Chemistry, Ivanovo State University of Chemistry and Technology, Sheremetevsky pr., 10, 153010 Ivanovo, Russia
- Pacific National University, 136 Tikhookeanskaya Street, 680035 Khabarovsk, Russia
| |
Collapse
|
6
|
Vital N, Ventura C, Kranendonk M, Silva MJ, Louro H. Toxicological Assessment of Cellulose Nanomaterials: Oral Exposure. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3375. [PMID: 36234501 PMCID: PMC9565252 DOI: 10.3390/nano12193375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Cellulose nanomaterials (CNMs) have emerged recently as an important group of sustainable bio-based nanomaterials (NMs) with potential applications in multiple sectors, including the food, food packaging, and biomedical fields. The widening of these applications leads to increased human oral exposure to these NMs and, potentially, to adverse health outcomes. Presently, the potential hazards regarding oral exposure to CNMs are insufficiently characterised. There is a need to understand and manage the potential adverse effects that might result from the ingestion of CNMs before products using CNMs reach commercialisation. This work reviews the potential applications of CNMs in the food and biomedical sectors along with the existing toxicological in vitro and in vivo studies, while also identifying current knowledge gaps. Relevant considerations when performing toxicological studies following oral exposure to CNMs are highlighted. An increasing number of studies have been published in the last years, overall showing that ingested CNMs are not toxic to the gastrointestinal tract (GIT), suggestive of the biocompatibility of the majority of the tested CNMs. However, in vitro and in vivo genotoxicity studies, as well as long-term carcinogenic or reproductive toxicity studies, are not yet available. These studies are needed to support a wider use of CNMs in applications that can lead to human oral ingestion, thereby promoting a safe and sustainable-by-design approach.
Collapse
Affiliation(s)
- Nádia Vital
- National Institute of Health Dr. Ricardo Jorge, Department of Human Genetics, 1649-016 Lisbon, Portugal
- NOVA Medical School, Universidade NOVA de Lisboa, 1169-056 Lisbon, Portugal
- Centre for Toxicogenomics and Human Health (ToxOmics), NOVA Medical School, Universidade NOVA de Lisboa, 1169-056 Lisbon, Portugal
| | - Célia Ventura
- National Institute of Health Dr. Ricardo Jorge, Department of Human Genetics, 1649-016 Lisbon, Portugal
- Centre for Toxicogenomics and Human Health (ToxOmics), NOVA Medical School, Universidade NOVA de Lisboa, 1169-056 Lisbon, Portugal
| | - Michel Kranendonk
- NOVA Medical School, Universidade NOVA de Lisboa, 1169-056 Lisbon, Portugal
- Centre for Toxicogenomics and Human Health (ToxOmics), NOVA Medical School, Universidade NOVA de Lisboa, 1169-056 Lisbon, Portugal
| | - Maria João Silva
- National Institute of Health Dr. Ricardo Jorge, Department of Human Genetics, 1649-016 Lisbon, Portugal
- Centre for Toxicogenomics and Human Health (ToxOmics), NOVA Medical School, Universidade NOVA de Lisboa, 1169-056 Lisbon, Portugal
| | - Henriqueta Louro
- National Institute of Health Dr. Ricardo Jorge, Department of Human Genetics, 1649-016 Lisbon, Portugal
- Centre for Toxicogenomics and Human Health (ToxOmics), NOVA Medical School, Universidade NOVA de Lisboa, 1169-056 Lisbon, Portugal
| |
Collapse
|
7
|
Brand W, van Kesteren PCE, Swart E, Oomen AG. Overview of potential adverse health effects of oral exposure to nanocellulose. Nanotoxicology 2022; 16:217-246. [PMID: 35624082 DOI: 10.1080/17435390.2022.2069057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Nanocellulose is an emerging material for which several food-related applications are foreseen, for example, novel food, functional food, food additive or in food contact materials. Nanocellulose materials can display a range of possible shapes (fibers, crystals), sizes and surface modifications. For food-related applications in the EU, information on the safety of substances must be assessed. The present review summarizes the current knowledge on (possible) adverse health effects of nanocellulose upon oral exposure, keeping EU regulatory aspects in mind. The overview indicates that toxicity data, especially from in vivo studies, are limited and outcomes are not unambiguous. The hazard assessment is further complicated by: the diversity in morphologies and surface modifications, lack of standard reference materials, limited knowledge about intestinal fate and absorption, analytical difficulties in biological matrices, dispersion issues, the possible presence of impurities and interferences within biological assays. Two subchronic in vivo toxicity studies show no indications of toxicity for two specific nanocellulose materials, even at high doses. However, these studies may have missed certain early or nano-specific toxic effects, such as inflammation potential, for which other, subacute studies provide some indications. Most in vitro studies show no cytotoxicity; however, several indicate that effects on oxidative stress and inflammatory responses depend on differences in size or surface treatments. Further, too few studies assessed genotoxicity of nanocelluloses. Therefore, immunotoxicity, oxidative stress and genotoxicity require further attention, as do absorption and effects on nutrient uptake. Recommendations for future research facilitating the safety assessment and safe-by-design of nanocellulose in food-related applications are provided.
Collapse
Affiliation(s)
- Walter Brand
- National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Petra C E van Kesteren
- National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Elmer Swart
- National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Agnes G Oomen
- National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| |
Collapse
|
8
|
Maceda A, Terrazas T. Fluorescence Microscopy Methods for the Analysis and Characterization of Lignin. Polymers (Basel) 2022; 14:polym14050961. [PMID: 35267784 PMCID: PMC8912355 DOI: 10.3390/polym14050961] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 02/19/2022] [Accepted: 02/20/2022] [Indexed: 02/04/2023] Open
Abstract
Lignin is one of the most studied and analyzed materials due to its importance in cell structure and in lignocellulosic biomass. Because lignin exhibits autofluorescence, methods have been developed that allow it to be analyzed and characterized directly in plant tissue and in samples of lignocellulose fibers. Compared to destructive and costly analytical techniques, fluorescence microscopy presents suitable alternatives for the analysis of lignin autofluorescence. Therefore, this review article analyzes the different methods that exist and that have focused specifically on the study of lignin because with the revised methods, lignin is characterized efficiently and in a short time. The existing qualitative methods are Epifluorescence and Confocal Laser Scanning Microscopy; however, other semi-qualitative methods have been developed that allow fluorescence measurements and to quantify the differences in the structural composition of lignin. The methods are fluorescence lifetime spectroscopy, two-photon microscopy, Föster resonance energy transfer, fluorescence recovery after photobleaching, total internal reflection fluorescence, and stimulated emission depletion. With these methods, it is possible to analyze the transport and polymerization of lignin monomers, distribution of lignin of the syringyl or guaiacyl type in the tissues of various plant species, and changes in the degradation of wood by pulping and biopulping treatments as well as identify the purity of cellulose nanofibers though lignocellulosic biomass.
Collapse
Affiliation(s)
- Agustín Maceda
- Laboratorio Nacional de Investigación y Servicio Agroalimentario y Forestal, Universidad Autónoma Chapingo, Texcoco 56230, Mexico;
| | - Teresa Terrazas
- Instituto de Biología, Universidad Nacional Autónoma de México, Mexico City 09230, Mexico
- Correspondence: ; Tel.: +52-555622-9116
| |
Collapse
|
9
|
Ventura J, Uriel C, Gomez AM, Avellanal-Zaballa E, Bañuelos J, García-Moreno I, Lopez JC. A Concise Synthesis of a BODIPY-Labeled Tetrasaccharide Related to the Antitumor PI-88. Molecules 2021; 26:2909. [PMID: 34068920 PMCID: PMC8156587 DOI: 10.3390/molecules26102909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/06/2021] [Accepted: 05/12/2021] [Indexed: 02/04/2023] Open
Abstract
A convergent synthetic route to a tetrasaccharide related to PI-88, which allows the incorporation of a fluorescent BODIPY-label at the reducing-end, has been developed. The strategy, which features the use of 1,2-methyl orthoesters (MeOEs) as glycosyl donors, illustrates the usefulness of suitably-designed BODIPY dyes as glycosyl labels in synthetic strategies towards fluorescently-tagged oligosaccharides.
Collapse
Affiliation(s)
- Juan Ventura
- Instituto de Química Orgánica General, IQOG-CSIC, Juan de la Cierva 3, 28006 Madrid, Spain; (J.V.); (C.U.)
| | - Clara Uriel
- Instituto de Química Orgánica General, IQOG-CSIC, Juan de la Cierva 3, 28006 Madrid, Spain; (J.V.); (C.U.)
| | - Ana M. Gomez
- Instituto de Química Orgánica General, IQOG-CSIC, Juan de la Cierva 3, 28006 Madrid, Spain; (J.V.); (C.U.)
| | - Edurne Avellanal-Zaballa
- Departamento de Química Física, Universidad del Pais Vasco-EHU, Apartado 644, 48080 Bilbao, Spain;
| | - Jorge Bañuelos
- Departamento de Química Física, Universidad del Pais Vasco-EHU, Apartado 644, 48080 Bilbao, Spain;
| | | | - Jose Cristobal Lopez
- Instituto de Química Orgánica General, IQOG-CSIC, Juan de la Cierva 3, 28006 Madrid, Spain; (J.V.); (C.U.)
| |
Collapse
|