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1257 KiB

Open AccessArticle

DNA-Aptamers Binding Aminoglycoside Antibiotics

by Nadia Nikolaus and Beate Strehlitz

Sensors 2014, 14(2), 3737-3755; https://doi.org/10.3390/s140203737 - 21 Feb 2014

Cited by 50 | Viewed by 10137

Aptamers are short, single stranded DNA or RNA oligonucleotides that are able to bind specifically and with high affinity to their non-nucleic acid target molecules. This binding reaction enables their application as biorecognition elements in biosensors and assays. As antibiotic residues pose a [...] Read more.

Aptamers are short, single stranded DNA or RNA oligonucleotides that are able to bind specifically and with high affinity to their non-nucleic acid target molecules. This binding reaction enables their application as biorecognition elements in biosensors and assays. As antibiotic residues pose a problem contributing to the emergence of antibiotic-resistant pathogens and thereby reducing the effectiveness of the drug to fight human infections, we selected aptamers targeted against the aminoglycoside antibiotic kanamycin A with the aim of constructing a robust and functional assay that can be used for water analysis. With this work we show that aptamers that were derived from a Capture-SELEX procedure targeting against kanamycin A also display binding to related aminoglycoside antibiotics. The binding patterns differ among all tested aptamers so that there are highly substance specific aptamers and more group specific aptamers binding to a different variety of aminoglycoside antibiotics. Also the region of the aminoglycoside antibiotics responsible for aptamer binding can be estimated. Affinities of the different aptamers for their target substance, kanamycin A, are measured with different approaches and are in the micromolar range. Finally, the proof of principle of an assay for detection of kanamycin A in a real water sample is given. Full article

(This article belongs to the Special Issue Aptasensors)

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407 KiB

Open AccessArticle

Development of an Antigen-DNAzyme Based Probe for a Direct Antibody-Antigen Assay Using the Intrinsic DNAzyme Activity of a Daunomycin Aptamer

by Noorsharmimi Omar, Qiuting Loh, Gee Jun Tye, Yee Siew Choong, Rahmah Noordin, Jörn Glökler and Theam Soon Lim

Sensors 2014, 14(1), 346-355; https://doi.org/10.3390/s140100346 - 27 Dec 2013

Cited by 9 | Viewed by 7043

Abstract

G-Quadruplex (G-4) structures are formed when G-rich DNA sequences fold into intra- or intermolecular four-stranded structures in the presence of metal ions. G-4-hemin complexes are often effective peroxidase-mimicking DNAzymes that are applied in many detection systems. This work reports the application of a [...] Read more.

G-Quadruplex (G-4) structures are formed when G-rich DNA sequences fold into intra- or intermolecular four-stranded structures in the presence of metal ions. G-4-hemin complexes are often effective peroxidase-mimicking DNAzymes that are applied in many detection systems. This work reports the application of a G-rich daunomycin-specific aptamer for the development of an antibody-antigen detection assay. We investigated the ability of the daunomycin aptamer to efficiently catalyze the hemin-dependent peroxidase activity independent of daunomycin. A reporter probe consisting of biotinylated antigen and daunomycin aptamer coupled to streptavidin gold nanoparticles was successfully used to generate a colorimetric readout. In conclusion, the daunomycin aptamer can function as a robust alternative DNAzyme for the development of colorimetric assays. Full article

(This article belongs to the Special Issue Aptasensors)

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1430 KiB

Open AccessArticle

Impedimetric Aptasensor for Ochratoxin A Determination Based on Au Nanoparticles Stabilized with Hyper-Branched Polymer

by Gennady Evtugyn, Anna Porfireva, Veronika Stepanova, Marianna Kutyreva, Alfiya Gataulina, Nikolay Ulakhovich, Vladimir Evtugyn and Tibor Hianik

Sensors 2013, 13(12), 16129-16145; https://doi.org/10.3390/s131216129 - 26 Nov 2013

Cited by 57 | Viewed by 8457

Abstract

An impedimetric aptasensor for ochratoxin A (OTA) detection has been developed on the base of a gold electrode covered with a new modifier consisting of electropolymerized Neutral Red and a mixture of Au nanoparticles suspended in the dendrimeric polymer Botlorn H30^®. [...] Read more.

An impedimetric aptasensor for ochratoxin A (OTA) detection has been developed on the base of a gold electrode covered with a new modifier consisting of electropolymerized Neutral Red and a mixture of Au nanoparticles suspended in the dendrimeric polymer Botlorn H30^®. Thiolated aptamer specific to OTA was covalently attached to Au nanoparticles via Au-S bonding. The interaction of the aptamer with OTA induced the conformational switch of the aptamer from linear to guanine quadruplex form followed by consolidation of the surface layer and an increase of the charge transfer resistance. The aptasensor makes it possible to detect from 0.1 to 100 nM of OTA (limit of detection: 0.02 nM) in the presence of at least 50 fold excess of ochratoxin B. The applicability of the aptasensor for real sample assay was confirmed by testing spiked beer samples. The recovery of 2 nM OTA was found to be 70% for light beer and 78% for dark beer. Full article

(This article belongs to the Special Issue Aptasensors)

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1128 KiB

Open AccessArticle

Biostable ssDNA Aptamers Specific for Hodgkin Lymphoma

by Parag Parekh, Sanchit Kamble, Nianxi Zhao, Zihua Zeng, Jianguo Wen, Bin Yuan and Youli Zu

Sensors 2013, 13(11), 14543-14557; https://doi.org/10.3390/s131114543 - 25 Oct 2013

Cited by 6 | Viewed by 6543

Abstract

As a “chemical antibody”, oligonucleotide aptamers can specifically bind to their target molecules. However, clinical potential of aptamers in disease diagnosis is not yet fully explored. Using a tumor cell-based selection protocol, we developed single-stranded DNA aptamers for Hodgkin lymphoma (HL) tumor cells. [...] Read more.

As a “chemical antibody”, oligonucleotide aptamers can specifically bind to their target molecules. However, clinical potential of aptamers in disease diagnosis is not yet fully explored. Using a tumor cell-based selection protocol, we developed single-stranded DNA aptamers for Hodgkin lymphoma (HL) tumor cells. The aptamers specifically bound to HL cells with a high affinity, reaching maximal cell binding at 10 nM final concentration. Importantly, the aptamers were able to selectively detect HL cells and did not react to other tumor or blood cells in mixed samples, indicating that the aptamers can be used as a specific probe for in vitro analysis of HL cells. Moreover, due to the inherent properties of DNA, the aptamers were stable in human serum, suggesting potential for in vivo detection of HL tumor cells. Full article

(This article belongs to the Special Issue Aptasensors)

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517 KiB

Open AccessArticle

Development of a Multiplex Sandwich Aptamer Microarray for the Detection of VEGF₁₆₅ and Thrombin

by Alice Sosic, Anna Meneghello, Agnese Antognoli, Erica Cretaio and Barbara Gatto

Sensors 2013, 13(10), 13425-13438; https://doi.org/10.3390/s131013425 - 03 Oct 2013

Cited by 26 | Viewed by 7307

Abstract

In this work we have developed a multiplex microarray system capable of detecting VEGF₁₆₅ and thrombin. We recently described a Sandwich Aptamer Microarray (SAM) for thrombin detection feasible for use in multiplex microarrays; here we describe a new aptasensor for VEGF₁₆₅ [...] Read more.

In this work we have developed a multiplex microarray system capable of detecting VEGF₁₆₅ and thrombin. We recently described a Sandwich Aptamer Microarray (SAM) for thrombin detection feasible for use in multiplex microarrays; here we describe a new aptasensor for VEGF₁₆₅ detection employing Vap7 and VEa5, two DNA aptamers recognizing different sites of the protein. The aptamers were modified to be adapted to the solid phase platform of SAM and their capability to simultaneously recognize VEGF₁₆₅ by forming a ternary complex was analyzed in solution. Having so defined the best tandem arrangement of modified aptamers, we set up the aptasensor for VEGF₁₆₅, and finally analyzed the multiplex system with the two aptasensors for the simultaneous detection of VEGF₁₆₅ and thrombin. The results indicate that each sandwich is specific, even when the two proteins are mixed. The system performance is consistent with the behavior evidenced by the biochemical analysis, which proves to be valuable to drive the evaluation and refinement of aptamers prior to or along the development of a detection platform. Since thrombin upregulates VEGF expression, the simultaneous recognition of these two proteins could be useful in the analysis of biomarkers in pathologies characterized by neo-angiogenesis. Full article

(This article belongs to the Special Issue Aptasensors)

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Review

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700 KiB

Open AccessReview

Smart Materials Based on DNA Aptamers: Taking Aptasensing to the Next Level

by Emily Mastronardi, Amanda Foster, Xueru Zhang and Maria C. DeRosa

Sensors 2014, 14(2), 3156-3171; https://doi.org/10.3390/s140203156 - 18 Feb 2014

Cited by 48 | Viewed by 10090

Abstract

“Smart” materials are an emerging category of multifunctional materials with physical or chemical properties that can be controllably altered in response to an external stimulus. By combining the standard properties of the advanced material with the unique ability to recognize and adapt in [...] Read more.

“Smart” materials are an emerging category of multifunctional materials with physical or chemical properties that can be controllably altered in response to an external stimulus. By combining the standard properties of the advanced material with the unique ability to recognize and adapt in response to a change in their environment, these materials are finding applications in areas such as sensing and drug delivery. While the majority of these materials are responsive to physical or chemical changes, a particularly exciting area of research seeks to develop smart materials that are sensitive to specific molecular or biomolecular stimuli. These systems require the integration of a molecular recognition probe specific to the target molecule of interest. The ease of synthesis and labeling, low cost, and stability of DNA aptamers make them uniquely suited to effectively serve as molecular recognition probes in novel smart material systems. This review will highlight current work in the area of aptamer-based smart materials and prospects for their future applications. Full article

(This article belongs to the Special Issue Aptasensors)

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598 KiB

Open AccessReview

Aptamer-Based Analysis: A Promising Alternative for Food Safety Control

by Sonia Amaya-González, Noemí De-los-Santos-Álvarez, Arturo J. Miranda-Ordieres and María Jesús Lobo-Castañón

Sensors 2013, 13(12), 16292-16311; https://doi.org/10.3390/s131216292 - 28 Nov 2013

Cited by 112 | Viewed by 14004

Abstract

Ensuring food safety is nowadays a top priority of authorities and professional players in the food supply chain. One of the key challenges to determine the safety of food and guarantee a high level of consumer protection is the availability of fast, sensitive [...] Read more.

Ensuring food safety is nowadays a top priority of authorities and professional players in the food supply chain. One of the key challenges to determine the safety of food and guarantee a high level of consumer protection is the availability of fast, sensitive and reliable analytical methods to identify specific hazards associated to food before they become a health problem. The limitations of existing methods have encouraged the development of new technologies, among them biosensors. Success in biosensor design depends largely on the development of novel receptors with enhanced affinity to the target, while being stable and economical. Aptamers fulfill these characteristics, and thus have surfaced as promising alternatives to natural receptors. This Review describes analytical strategies developed so far using aptamers for the control of pathogens, allergens, adulterants, toxins and other forbidden contaminants to ensure food safety. The main progresses to date are presented, highlighting potential prospects for the future. Full article

(This article belongs to the Special Issue Aptasensors)

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396 KiB

Open AccessReview

Recent Advances and Achievements in Nanomaterial-Based, and Structure Switchable Aptasensing Platforms for Ochratoxin A Detection

by Akhtar Hayat, Cheng Yang, Amina Rhouati and Jean Louis Marty

Sensors 2013, 13(11), 15187-15208; https://doi.org/10.3390/s131115187 - 06 Nov 2013

Cited by 48 | Viewed by 7983

Abstract

Aptamer-based bioreceptors that can easily adopt their surroundings have captured the attention of scientists from a wide spectrum of domains in designing highly sensitive, selective and structure switchable sensing assays. Through elaborate design and chemical functionalization, numerous aptamer-based assays have been developed that [...] Read more.

Aptamer-based bioreceptors that can easily adopt their surroundings have captured the attention of scientists from a wide spectrum of domains in designing highly sensitive, selective and structure switchable sensing assays. Through elaborate design and chemical functionalization, numerous aptamer-based assays have been developed that can switch their conformation upon incubation with target analyte, resulting in an enhanced output signal. To further lower the detection limits to picomolar levels, nanomaterials have attracted great interest in the design of aptamer-based sensing platforms. Associated to their unique properties, nanomaterials offer great promise for numerous aptasensing applications. This review will discuss current research activities in the aptasensing with typical example of detection of ochratoxin A (OTA). OTA, a secondary fungal metabolite, contaminates a variety of food commodities, and has several toxicological effects such as nephrotoxic, hepatotoxic, neurotoxic, teratogenic and immunotoxic activities. The review will introduce advances made in the methods of integrating nanomaterials in aptasensing, and will discuss current conformational switchable design strategies in aptasensor fabrication methodologies. Full article

(This article belongs to the Special Issue Aptasensors)

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449 KiB

Open AccessReview

Aptamers as Theranostic Agents: Modifications, Serum Stability and Functionalisation

by Sarah Shigdar, Joanna Macdonald, Michael O'Connor, Tao Wang, Dongxi Xiang, Hadi Al.Shamaileh, Liang Qiao, Ming Wei, Shu-Feng Zhou, Yimin Zhu, Lingxue Kong, Santanu Bhattacharya, ChunGuang Li and Wei Duan

Sensors 2013, 13(10), 13624-13637; https://doi.org/10.3390/s131013624 - 10 Oct 2013

Cited by 103 | Viewed by 11187

Abstract

Aptamers, and the selection process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX) used to generate them, were first described more than twenty years ago. Since then, there have been numerous modifications to the selection procedures. This review discusses the use [...] Read more.

Aptamers, and the selection process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX) used to generate them, were first described more than twenty years ago. Since then, there have been numerous modifications to the selection procedures. This review discusses the use of modified bases as a means of enhancing serum stability and producing effective therapeutic tools, as well as functionalising these nucleic acids to be used as potential diagnostic agents. Full article

(This article belongs to the Special Issue Aptasensors)

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