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Schaudy E, Ibañez-Redín G, Parlar E, Somoza MM, Lietard J. Nonaqueous Oxidation in DNA Microarray Synthesis Improves the Oligonucleotide Quality and Preserves Surface Integrity on Gold and Indium Tin Oxide Substrates. Anal Chem 2024; 96:2378-2386. [PMID: 38285499 PMCID: PMC10867803 DOI: 10.1021/acs.analchem.3c04166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/29/2023] [Accepted: 12/29/2023] [Indexed: 01/30/2024]
Abstract
Nucleic acids attached to electrically conductive surfaces are very frequently used platforms for sensing and analyte detection as well as for imaging. Synthesizing DNA on these uncommon substrates and preserving the conductive layer is challenging as this coating tends to be damaged by the repeated use of iodine and water, which is the standard oxidizing medium following phosphoramidite coupling. Here, we thoroughly investigate the use of camphorsulfonyl oxaziridine (CSO), a nonaqueous alternative to I2/H2O, for the synthesis of DNA microarrays in situ. We find that CSO performs equally well in producing high hybridization signals on glass microscope slides, and CSO also protects the conductive layer on gold and indium tin oxide (ITO)-coated slides. DNA synthesis on conductive substrates with CSO oxidation yields microarrays of quality approaching that of conventional glass with intact physicochemical properties.
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Affiliation(s)
- Erika Schaudy
- Institute
of Inorganic Chemistry, University of Vienna, Josef-Holaubek-Platz 2, Vienna 1090, Austria
| | - Gisela Ibañez-Redín
- Institute
of Inorganic Chemistry, University of Vienna, Josef-Holaubek-Platz 2, Vienna 1090, Austria
| | - Etkin Parlar
- Institute
of Inorganic Chemistry, University of Vienna, Josef-Holaubek-Platz 2, Vienna 1090, Austria
| | - Mark M. Somoza
- Institute
of Inorganic Chemistry, University of Vienna, Josef-Holaubek-Platz 2, Vienna 1090, Austria
- Leibniz-Institute
for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Straße 30, Freising 85354, Germany
- Chair
of Food Chemistry and Molecular Sensory Science, Technical University of Munich, Lise-Meitner-Straße 34, Freising 85354, Germany
| | - Jory Lietard
- Institute
of Inorganic Chemistry, University of Vienna, Josef-Holaubek-Platz 2, Vienna 1090, Austria
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2
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Lietard J, Leger A, Erlich Y, Sadowski N, Timp W, Somoza MM. Chemical and photochemical error rates in light-directed synthesis of complex DNA libraries. Nucleic Acids Res 2021; 49:6687-6701. [PMID: 34157124 PMCID: PMC8266620 DOI: 10.1093/nar/gkab505] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/24/2021] [Accepted: 06/17/2021] [Indexed: 11/30/2022] Open
Abstract
Nucleic acid microarrays are the only tools that can supply very large oligonucleotide libraries, cornerstones of the nascent fields of de novo gene assembly and DNA data storage. Although the chemical synthesis of oligonucleotides is highly developed and robust, it is not error free, requiring the design of methods that can correct or compensate for errors, or select for high-fidelity oligomers. However, outside the realm of array manufacturers, little is known about the sources of errors and their extent. In this study, we look at the error rate of DNA libraries synthesized by photolithography and dissect the proportion of deletion, insertion and substitution errors. We find that the deletion rate is governed by the photolysis yield. We identify the most important substitution error and correlate it to phosphoramidite coupling. Besides synthetic failures originating from the coupling cycle, we uncover the role of imperfections and limitations related to optics, highlight the importance of absorbing UV light to avoid internal reflections and chart the dependence of error rate on both position on the array and position within individual oligonucleotides. Being able to precisely quantify all types of errors will allow for optimal choice of fabrication parameters and array design.
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Affiliation(s)
- Jory Lietard
- Institute of Inorganic Chemistry, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
| | - Adrien Leger
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | | | - Norah Sadowski
- Johns Hopkins University, Department of Molecular Biology and Genetics, Baltimore, MD, USA
| | - Winston Timp
- Johns Hopkins University, Department of Molecular Biology and Genetics, Baltimore, MD, USA.,Johns Hopkins University, Departments of Biomedical Engineering, Molecular Biology and Genetics and Medicine, Division of Infectious Disease, Baltimore, MD, USA
| | - Mark M Somoza
- Institute of Inorganic Chemistry, University of Vienna, Althanstraße 14, 1090 Vienna, Austria.,Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich, Lise-Meitner-Straße 34, 85354 Freising, Germany.,Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Straße 34, 85354 Freising, Germany
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3
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Shlyapnikov YM, Malakhova EA, Shlyapnikova EA. Improving Immunoassay Performance with Cleavable Blocking of Microarrays. Anal Chem 2021; 93:1126-1134. [PMID: 33305941 DOI: 10.1021/acs.analchem.0c04175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Among the key issues that are commonly associated with the development of microarray-based assays are nonspecific binding and diffusion constraints. Here we present a novel strategy addressing both of these challenges simultaneously. The essence of the method consists in blocking the microarray surface with a blocking agent containing a perfluoroalkyl chain and a disulfide linker. The resulting surface is hydrophobic, and no immiscible liquid layer remains on it upon cyclically draining and replenishing the sample solution, ensuring an efficient mass transfer of an analyte onto a microarray. Prior to the signal detection procedure, disulfide bonds are chemically cleaved, and the perfluoroalkyl chains are removed from the microarray surface along with nonspecifically adsorbed proteins, resulting in extremely low background. Using conventional fluorescent detection, we show a 30-fold increase in signal/background ratio compared to a common epoxy-modified glass substrate. The combination of this technique with magnetic beads detection results in a simple and ultrasensitive cholera toxin (CT) immunoassay. The limit of detection (LOD) is 1 fM, which is achieved with an analyte binding time of 1 h. Efficient mass transfer provides highly sensitive detection of whole virus particles despite their low diffusion coefficient. The achieved LOD for vaccinia virus is 104 particles in 1 mL of sample. Finally, we have performed for the first time the simultaneous detection of whole virus and CT protein biomarker in a single assay. The developed technique can be used for multiplex detection of trace amounts of pathogens of various natures.
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Affiliation(s)
- Yuri M Shlyapnikov
- Institute of Theoretical and Experimental Biophysics Russian Academy of Sciences, Pushchino 142290, Russia
| | - Ekaterina A Malakhova
- Institute of Theoretical and Experimental Biophysics Russian Academy of Sciences, Pushchino 142290, Russia
| | - Elena A Shlyapnikova
- Institute of Theoretical and Experimental Biophysics Russian Academy of Sciences, Pushchino 142290, Russia
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Antkowiak PL, Lietard J, Darestani MZ, Somoza MM, Stark WJ, Heckel R, Grass RN. Low cost DNA data storage using photolithographic synthesis and advanced information reconstruction and error correction. Nat Commun 2020; 11:5345. [PMID: 33093494 PMCID: PMC7582880 DOI: 10.1038/s41467-020-19148-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 09/29/2020] [Indexed: 12/02/2022] Open
Abstract
Due to its longevity and enormous information density, DNA is an attractive medium for archival storage. The current hamstring of DNA data storage systems-both in cost and speed-is synthesis. The key idea for breaking this bottleneck pursued in this work is to move beyond the low-error and expensive synthesis employed almost exclusively in today's systems, towards cheaper, potentially faster, but high-error synthesis technologies. Here, we demonstrate a DNA storage system that relies on massively parallel light-directed synthesis, which is considerably cheaper than conventional solid-phase synthesis. However, this technology has a high sequence error rate when optimized for speed. We demonstrate that even in this high-error regime, reliable storage of information is possible, by developing a pipeline of algorithms for encoding and reconstruction of the information. In our experiments, we store a file containing sheet music of Mozart, and show perfect data recovery from low synthesis fidelity DNA.
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Affiliation(s)
- Philipp L Antkowiak
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, 8093, Zürich, Switzerland
| | - Jory Lietard
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Althanstraße 14, A-1090, Vienna, Austria
| | - Mohammad Zalbagi Darestani
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX, 77005, USA
| | - Mark M Somoza
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Althanstraße 14, A-1090, Vienna, Austria
- Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich, Lise-Meitner-Straße 34, 85354, Freising, Germany
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Straße 34, 85354, Freising, Germany
| | - Wendelin J Stark
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, 8093, Zürich, Switzerland
| | - Reinhard Heckel
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX, 77005, USA.
- Department of Electrical and Computer Engineering, Technical University of Munich, Theresienstr. 90, 80333, Munich, Germany.
| | - Robert N Grass
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, 8093, Zürich, Switzerland.
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Lietard J, Somoza MM. Spotting, Transcription and In Situ Synthesis: Three Routes for the Fabrication of RNA Microarrays. Comput Struct Biotechnol J 2019; 17:862-868. [PMID: 31321002 PMCID: PMC6612525 DOI: 10.1016/j.csbj.2019.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 06/04/2019] [Accepted: 06/08/2019] [Indexed: 12/11/2022] Open
Abstract
DNA microarrays have become commonplace in the last two decades, but the synthesis of other nucleic acids biochips, most importantly RNA, has only recently been developed to a similar extent. RNA microarrays can be seen as organized surfaces displaying a potentially very large number of unique sequences and are of invaluable help in understanding the complexity of RNA structure and function as they allow the probing and treatment of each of the many different sequences simultaneously. Three approaches have emerged for the fabrication of RNA microarrays. The earliest examples used a direct, manual or mechanical, deposition of pre-synthesized, purified RNA oligonucleotides onto the surface in a process called spotting. In a second approach, pre-spotted or in situ-synthesized DNA microarrays are employed as templates for the transcription of RNA, subsequently or immediately captured on the surface. Finally, a third approach attempts to mirror the phosphoramidite-based protocols for in situ synthesis of high-density DNA arrays in order to produce in situ synthesized RNA microarrays. In this mini-review, we describe the chemistry and the engineering behind the fabrications methods, underlining the advantages and shortcomings of each, and illustrate how versatile these platforms can be by presenting some of their applications.
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Sack M, Hölz K, Holik AK, Kretschy N, Somoza V, Stengele KP, Somoza MM. Express photolithographic DNA microarray synthesis with optimized chemistry and high-efficiency photolabile groups. J Nanobiotechnology 2016; 14:14. [PMID: 26936369 PMCID: PMC4776362 DOI: 10.1186/s12951-016-0166-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/17/2016] [Indexed: 12/16/2022] Open
Abstract
Background DNA microarrays are a core element of modern genomics research and medical diagnostics, allowing the simple and simultaneous determination of the relative abundances of hundreds of thousands to millions of genomic DNA or RNA sequences in a sample. Photolithographic in situ synthesis, using light projection from a digitally-controlled array of micromirrors, has been successful at both commercial and laboratory scales. The advantages of this synthesis method are its ability to reliably produce high-quality custom microarrays with a very high spatial density of DNA features using a compact device with few moving parts. The phosphoramidite chemistry used in photolithographic synthesis is similar to that used in conventional solid-phase synthesis of oligonucleotides, but some unique differences require an independent optimization of the synthesis chemistry to achieve fast and low-cost synthesis without compromising microarray quality. Results High microarray quality could be maintained while reducing coupling time to a few seconds using DCI activator. Five coupling activators were compared, which resulted in microarray hybridization signals following the order ETT > Activator 42 > DCI ≫ BTT ≫ pyridinium chloride, but only the use of DCI led to both high signal and highly uniform feature intensities. The photodeprotection time was also reduced to a few seconds by replacing the NPPOC photolabile group with the new thiophenyl-NPPOC group. Other chemical parameters, such as oxidation and washing steps were also optimized. Conclusions Highly optimized and microarray-specific phosphoramidite chemistry, along with the use of the very photosensitive thiophenyl-NPPOC protecting group allow for the synthesis of high-complexity DNA arrays using coupling times of 15 s and deprotection times of 9 s. The resulting overall cycle time (coupling to coupling) of about 50 s, results in a three-fold reduction in synthesis time.
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Affiliation(s)
- Matej Sack
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria.
| | - Kathrin Hölz
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria.
| | - Ann-Katrin Holik
- Department of Nutritional and Physiological Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria.
| | - Nicole Kretschy
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria.
| | - Veronika Somoza
- Department of Nutritional and Physiological Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria. .,Christian Doppler Laboratory for Bioactive Aroma Compounds, University of Vienna, Vienna, Austria.
| | | | - Mark M Somoza
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria.
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