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Fagúndez P, Botasini S, Tosar JP, Méndez E. Systematic process evaluation of the conjugation of proteins to gold nanoparticles. Heliyon 2021; 7:e07392. [PMID: 34307927 PMCID: PMC8258641 DOI: 10.1016/j.heliyon.2021.e07392] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 05/22/2021] [Accepted: 06/21/2021] [Indexed: 11/30/2022] Open
Abstract
The present work addresses some fundamental aspects in the preparation of protein-conjugated gold nanoparticles, in order to ensure an appropriate final product. Ten broadly available and/or easy to implement analytical tools were benchmarked and compared in their capacity to provide reliable and conclusive information for each step of the procedure. These techniques included transmission electron microscopy, UV/VIS spectroscopy, dynamic light scattering, zeta-potential, Fourier-transformed infrared spectroscopy, colloidal stability titration, end-point colloidal stability analysis, cyclic voltammetry, agarose gel electrophoresis and size-exclusion chromatography (SEC). Four different proteins widely used as adaptors or blocking agents were tested, together with 13 nm gold nanoparticles containing different surface chemistries. Among all tested techniques, some of the least popular among nanomaterial scientists probed to be the most informative, including colloidal stability, gel electrophoresis and SEC; the latter being also an efficient purification procedure. These three techniques provide low-cost, low time consuming, sensitive and robust ways to assess the success of the nanoparticle bioconjugation steps, especially when used in adequate combinations.
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Affiliation(s)
- Pablo Fagúndez
- Unidad de Bioquímica Analítica, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, 11400, Montevideo, Uruguay.,Graduate Program in Chemistry, Facultad de Química, Universidad de la República, Uruguay
| | - Santiago Botasini
- Laboratorio de Biomateriales, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, 11400, Montevideo, Uruguay
| | - Juan Pablo Tosar
- Unidad de Bioquímica Analítica, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, 11400, Montevideo, Uruguay
| | - Eduardo Méndez
- Laboratorio de Biomateriales, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, 11400, Montevideo, Uruguay
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Méndez E, Fagúndez P, Sosa P, Gutiérrez MV, Botasini S. Experimental evidences support the existence of an aggregation/disaggregation step in the Turkevich synthesis of gold nanoparticles. Nanotechnology 2021; 32:045603. [PMID: 33036011 DOI: 10.1088/1361-6528/abbfd5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Turkevich method is one of the most employed techniques to synthesize gold nanoparticles. Despite its simplicity, the mechanism has been an issue of debate over the past years. The general belief is that particles are formed by a classical nucleation and growth theory, originally described by LaMer's model. In the present work, we provide new experimental evidences that supports either LaMer's theory and their detractors. In the former model, it is proposed that particles are generated by a burst nucleation form the initial 'seeds', from which their growth in a second and quasi-independent step. Instead, our experiments (DLS, UV/VIS and TEM measurements) support the idea that nanoparticles 'seeds' tend to form large intermediate clusters at the beginning of the synthesis, that afterwards disassemble to yield the final nanoparticles. However, unlike other reports, we propose that during the cluster formation the particles do not coalesce, instead they come close to each other without losing their identity. As the synthesis continues, these clusters are progressively separated into the final particles. As a consequence, a path to synthesize ultra-narrow size nanoparticles is provided, along with their stability against salt aggregation, and shelf-time. We found that these ultra-homogeneous nanoparticles are stable for several months, making them suitable for many applications in the biomedical and analytical research.
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Affiliation(s)
- Eduardo Méndez
- Laboratorio de Biomateriales, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República. Iguá 4225, 11400 Montevideo, Uruguay
| | - Pablo Fagúndez
- Unidad de Bioquímica Analítica, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Uruguay
| | - Paola Sosa
- Laboratorio de Biomateriales, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República. Iguá 4225, 11400 Montevideo, Uruguay
| | - María Victoria Gutiérrez
- Laboratorio de Biomateriales, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República. Iguá 4225, 11400 Montevideo, Uruguay
| | - Santiago Botasini
- Laboratorio de Biomateriales, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República. Iguá 4225, 11400 Montevideo, Uruguay
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Tosar JP, Segovia M, Castellano M, Gámbaro F, Akiyama Y, Fagúndez P, Olivera Á, Costa B, Possi T, Hill M, Ivanov P, Cayota A. Fragmentation of extracellular ribosomes and tRNAs shapes the extracellular RNAome. Nucleic Acids Res 2020; 48:12874-12888. [PMID: 32785615 PMCID: PMC7736827 DOI: 10.1093/nar/gkaa674] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 07/19/2020] [Accepted: 07/31/2020] [Indexed: 12/14/2022] Open
Abstract
A major proportion of extracellular RNAs (exRNAs) do not copurify with extracellular vesicles (EVs) and remain in ultracentrifugation supernatants of cell-conditioned medium or mammalian blood serum. However, little is known about exRNAs beyond EVs. We have previously shown that the composition of the nonvesicular exRNA fraction is highly biased toward specific tRNA-derived fragments capable of forming RNase-protecting dimers. To solve the problem of stability in exRNA analysis, we developed a method based on sequencing the size exclusion chromatography (SEC) fractions of nonvesicular extracellular samples treated with RNase inhibitors (RI). This method revealed dramatic compositional changes in exRNA population when enzymatic RNA degradation was inhibited. We demonstrated the presence of ribosomes and full-length tRNAs in cell-conditioned medium of a variety of mammalian cell lines. Their fragmentation generates some small RNAs that are highly resistant to degradation. The extracellular biogenesis of some of the most abundant exRNAs demonstrates that extracellular abundance is not a reliable input to estimate RNA secretion rates. Finally, we showed that chromatographic fractions containing extracellular ribosomes are probably not silent from an immunological perspective and could possibly be decoded as damage-associated molecular patterns.
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Affiliation(s)
- Juan Pablo Tosar
- Analytical Biochemistry Unit. Nuclear Research Center. Faculty of Science. Universidad de la República, Uruguay
- Functional Genomics Unit, Institut Pasteur de Montevideo, Uruguay
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Mercedes Segovia
- Laboratory of Immunoregulation and Inflammation, Institut Pasteur de Montevideo, Uruguay. Immunobiology Department, Faculty of Medicine, Universidad de la República, Uruguay
| | - Mauricio Castellano
- Analytical Biochemistry Unit. Nuclear Research Center. Faculty of Science. Universidad de la República, Uruguay
- Functional Genomics Unit, Institut Pasteur de Montevideo, Uruguay
| | - Fabiana Gámbaro
- Functional Genomics Unit, Institut Pasteur de Montevideo, Uruguay
- Molecular Virology Laboratory, Nuclear Research Center. Faculty of Science. Universidad de la República, Uruguay
| | - Yasutoshi Akiyama
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Pablo Fagúndez
- Analytical Biochemistry Unit. Nuclear Research Center. Faculty of Science. Universidad de la República, Uruguay
- Functional Genomics Unit, Institut Pasteur de Montevideo, Uruguay
| | - Álvaro Olivera
- Centro Universitario Regional Este, Universidad de la República, Uruguay
| | - Bruno Costa
- Analytical Biochemistry Unit. Nuclear Research Center. Faculty of Science. Universidad de la República, Uruguay
- Functional Genomics Unit, Institut Pasteur de Montevideo, Uruguay
| | - Tania Possi
- Functional Genomics Unit, Institut Pasteur de Montevideo, Uruguay
| | - Marcelo Hill
- Laboratory of Immunoregulation and Inflammation, Institut Pasteur de Montevideo, Uruguay. Immunobiology Department, Faculty of Medicine, Universidad de la República, Uruguay
| | - Pavel Ivanov
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
- The Broad Institute of Harvard and M.I.T., Cambridge, MA, USA
| | - Alfonso Cayota
- Functional Genomics Unit, Institut Pasteur de Montevideo, Uruguay
- Department of Medicine, University Hospital, Universidad de la República, Uruguay
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Fagúndez P, Brañas G, Laíz J, Tosar JP. Electrochemical Detection of dsDNA-Specific Antibodies. Methods Mol Biol 2020; 2063:73-83. [PMID: 31667764 DOI: 10.1007/978-1-0716-0138-9_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electrochemical biosensors have shown great promise as useful point-of-care tests since they operate on electronic circuits which can be miniaturized and whose readout process can be easily automated. Here, we describe a method for the electrochemical sensing of antibodies directed against double-stranded DNA (α-dsDNA), which are often present at higher-than-normal levels in the sera of autoimmune disease patients. The method can be easily implemented in any lab and requires little investment in equipment, namely a potentiostat. An artificial reference serum sample containing known amounts of spiked-in α-dsDNA antibodies enables reporting results in absolute scale rather than titer. Once electrodes are modified with DNA and the calibration curves are made (i.e., after the biosensor construction phase), individual measurements in test samples can be obtained in as low as 35 min.
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Affiliation(s)
- Pablo Fagúndez
- Analytical Biochemistry Unit, Nuclear Research Center, Faculty of Science, Universidad de la República, Montevideo, Uruguay
| | - Gustavo Brañas
- Analytical Biochemistry Unit, Nuclear Research Center, Faculty of Science, Universidad de la República, Montevideo, Uruguay
| | - Justo Laíz
- Analytical Biochemistry Unit, Nuclear Research Center, Faculty of Science, Universidad de la República, Montevideo, Uruguay
| | - Juan Pablo Tosar
- Analytical Biochemistry Unit, Nuclear Research Center, Faculty of Science, Universidad de la República, Montevideo, Uruguay.
- Functional Genomics Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay.
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Gámbaro F, Li Calzi M, Fagúndez P, Costa B, Greif G, Mallick E, Lyons S, Ivanov P, Witwer K, Cayota A, Tosar JP. Stable tRNA halves can be sorted into extracellular vesicles and delivered to recipient cells in a concentration-dependent manner. RNA Biol 2019; 17:1168-1182. [PMID: 31885318 DOI: 10.1080/15476286.2019.1708548] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Extracellular vesicles (EVs) are cell-derived nanoparticles that act as natural carriers of nucleic acids between cells. They offer advantages as delivery vehicles for therapeutic nucleic acids such as small RNAs. Loading of desired nucleic acids into EVs can be achieved by electroporation or transfection once purified. An attractive alternative is to transfect cells with the desired small RNAs and harness the cellular machinery for RNA sorting into the EVs. This possibility has been less explored because cells are believed to secrete only specific RNAs. However, we hypothesized that, even in the presence of selective secretion, concentration-driven RNA sorting to EVs would still be feasible. To show this, we transfected cells with glycine 5' tRNA halves, which we have previously shown to better resist RNases. We then measured their levels in EVs and in recipient cells and found that, in contrast to unstable RNAs of random sequence, these tRNA halves were present in vesicles and in recipient cells in amounts proportional to the concentration of RNA used for transfection. Similar efficiencies were obtained with other stable oligonucleotides of random sequence. Our results demonstrate that RNA stability is a key factor needed to maintain high intracellular concentrations, a prerequisite for efficient non-selective RNA sorting to EVs and delivery to cells. Given that glycine 5' tRNA halves belong to the group of stress-induced tRNA fragments frequently detected in extracellular space and biofluids, we propose that upregulation of extracellular tRNA fragments is consequential to cellular stress and might be involved in intercellular signalling.
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Affiliation(s)
- Fabiana Gámbaro
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay.,Molecular Virology Laboratory, Nuclear Research Center, Faculty of Science, Universidad de la República , Montevideo, Uruguay
| | - Marco Li Calzi
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay
| | - Pablo Fagúndez
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay.,Analytical Biochemistry Unit, Nuclear Research Center, Faculty of Science, Universidad de la República , Montevideo, Uruguay
| | - Bruno Costa
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay.,Analytical Biochemistry Unit, Nuclear Research Center, Faculty of Science, Universidad de la República , Montevideo, Uruguay
| | - Gonzalo Greif
- Molecular Biology Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay
| | - Emily Mallick
- Molecular and Comparative Pathobiology, and Neurology, The Johns Hopkins University School of Medicine , Baltimore, MD, USA
| | - Shawn Lyons
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital , Boston, MA, USA.,Department of Medicine, Harvard Medical School , Boston, MA, USA.,Department of Biochemistry, and The Genome Science Institute, Boston University School of Medicine , Boston, MA, USA
| | - Pavel Ivanov
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital , Boston, MA, USA.,Department of Medicine, Harvard Medical School , Boston, MA, USA.,The Broad Institute of Harvard and M.I.T ., Cambridge, MA, USA
| | - Kenneth Witwer
- Molecular and Comparative Pathobiology, and Neurology, The Johns Hopkins University School of Medicine , Baltimore, MD, USA
| | - Alfonso Cayota
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay.,Department of Medicine, Faculty of Medicine, Universidad de la República , Montevideo, Uruguay
| | - Juan Pablo Tosar
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay.,Analytical Biochemistry Unit, Nuclear Research Center, Faculty of Science, Universidad de la República , Montevideo, Uruguay
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Fagúndez P, Brañas G, Cairoli E, Laíz J, Tosar JP. An electrochemical biosensor for rapid detection of anti-dsDNA antibodies in absolute scale. Analyst 2018; 143:3874-3882. [DOI: 10.1039/c8an00020d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The authors report an electrochemical biosensor enabling fast (30 min) detection of anti-DNA antibodies in serum with reduced manipulation steps.
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Affiliation(s)
- Pablo Fagúndez
- Analytical Biochemistry Unit
- Nuclear Research Center
- Faculty of Science
- Universidad de la República
- Montevideo 11400
| | - Gustavo Brañas
- Analytical Biochemistry Unit
- Nuclear Research Center
- Faculty of Science
- Universidad de la República
- Montevideo 11400
| | - Ernesto Cairoli
- Systemic Autoimmune Diseases Unit
- Clínica Médica C
- Hospital de Clínicas
- Universidad de la República
- Montevideo 11600
| | - Justo Laíz
- Analytical Biochemistry Unit
- Nuclear Research Center
- Faculty of Science
- Universidad de la República
- Montevideo 11400
| | - Juan Pablo Tosar
- Analytical Biochemistry Unit
- Nuclear Research Center
- Faculty of Science
- Universidad de la República
- Montevideo 11400
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Doldán X, Fagúndez P, Cayota A, Laíz J, Tosar JP. Electrochemical Sandwich Immunosensor for Determination of Exosomes Based on Surface Marker-Mediated Signal Amplification. Anal Chem 2016; 88:10466-10473. [DOI: 10.1021/acs.analchem.6b02421] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Ximena Doldán
- Analytical
Biochemistry Unit, Nuclear Research Center, Faculty of Sciences, Universidad de la República, Mataojo 2055, Montevideo 11400, Uruguay
| | - Pablo Fagúndez
- Analytical
Biochemistry Unit, Nuclear Research Center, Faculty of Sciences, Universidad de la República, Mataojo 2055, Montevideo 11400, Uruguay
| | - Alfonso Cayota
- Functional
Genomics Laboratory, Institut Pasteur de Montevideo. Mataojo 2020, Montevideo 11400, Uruguay
- Department
of Medicine, Faculty of Medicine, Universidad de la República, Av. Italia S/N, Montevideo 11600, Uruguay
| | - Justo Laíz
- Analytical
Biochemistry Unit, Nuclear Research Center, Faculty of Sciences, Universidad de la República, Mataojo 2055, Montevideo 11400, Uruguay
| | - Juan Pablo Tosar
- Analytical
Biochemistry Unit, Nuclear Research Center, Faculty of Sciences, Universidad de la República, Mataojo 2055, Montevideo 11400, Uruguay
- Functional
Genomics Laboratory, Institut Pasteur de Montevideo. Mataojo 2020, Montevideo 11400, Uruguay
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