3,320 research outputs found
Design Strategies for Aptamer-Based Biosensors
Aptamers have been widely used as recognition elements for biosensor construction, especially in the detection of proteins or small molecule targets, and regarded as promising alternatives for antibodies in bioassay areas. In this review, we present an overview of reported design strategies for the fabrication of biosensors and classify them into four basic modes: target-induced structure switching mode, sandwich or sandwich-like mode, target-induced dissociation/displacement mode and competitive replacement mode. In view of the unprecedented advantages brought about by aptamers and smart design strategies, aptamer-based biosensors are expected to be one of the most promising devices in bioassay related applications
Recommended from our members
Three-dimensional modeling of single stranded DNA hairpins for aptamer-based biosensors.
Aptamers consist of short oligonucleotides that bind specific targets. They provide advantages over antibodies, including robustness, low cost, and reusability. Their chemical structure allows the insertion of reporter molecules and surface-binding agents in specific locations, which have been recently exploited for the development of aptamer-based biosensors and direct detection strategies. Mainstream use of these devices, however, still requires significant improvements in optimization for consistency and reproducibility. DNA aptamers are more stable than their RNA counterparts for biomedical applications but have the disadvantage of lacking the wide array of computational tools for RNA structural prediction. Here, we present the first approach to predict from sequence the three-dimensional structures of single stranded (ss) DNA required for aptamer applications, focusing explicitly on ssDNA hairpins. The approach consists of a pipeline that integrates sequentially building ssDNA secondary structure from sequence, constructing equivalent 3D ssRNA models, transforming the 3D ssRNA models into ssDNA 3D structures, and refining the resulting ssDNA 3D structures. Through this pipeline, our approach faithfully predicts the representative structures available in the Nucleic Acid Database and Protein Data Bank databases. Our results, thus, open up a much-needed avenue for integrating DNA in the computational analysis and design of aptamer-based biosensors
Recommended from our members
Aptamers in oncology: a diagnostic perspective
Nucleic acid sequences can produce a wide variety of three-dimensional conformations. Some of these structural forms are able to interact with proteins and small molecules with high affinity and specificity. These sequences, comprising either double or single stranded oligonucleotides, are called 'aptamers' based on the Greek word aptus, which means 'to fit'. Using an efficient selection process, randomised oligonucleotide libraries can be rapidly screened for aptamers with the appropriate binding characteristics. This technology has spawned the development of a new class of oligonucleotide therapeutic products. However, while interest among pharmaceutical companies continues to grow with some candidates already in clinical trials and one in the market, there appears to be some reluctance to fully explore the diagnostic potential of this technology. This article will review aptamer developments in diagnostics, compare them with other oligonucleotide therapeutics and highlight both potentials and pitfalls of technological development in this area
Recent Progress in Optical Sensors for Biomedical Diagnostics
In recent years, several types of optical sensors have been probed for their aptitude in healthcare biosensing, making their applications in biomedical diagnostics a rapidly evolving subject. Optical sensors show versatility amongst different receptor types and even permit the integration of different detection mechanisms. Such conjugated sensing platforms facilitate the exploitation of their neoteric synergistic characteristics for sensor fabrication. This paper covers nearly 250 research articles since 2016 representing the emerging interest in rapid, reproducible and ultrasensitive assays in clinical analysis. Therefore, we present an elaborate review of biomedical diagnostics with the help of optical sensors working on varied principles such as surface plasmon resonance, localised surface plasmon resonance, evanescent wave fluorescence, bioluminescence and several others. These sensors are capable of investigating toxins, proteins, pathogens, disease biomarkers and whole cells in varied sensing media ranging from water to buffer to more complex environments such as serum, blood or urine. Hence, the recent trends discussed in this review hold enormous potential for the widespread use of optical sensors in early-stage disease prediction and point-of-care testing devices.DFG, 428780268, Biomimetische Rezeptoren auf NanoMIP-Basis zur Virenerkennung und -entfernung mittels integrierter AnsÀtz
Voltammetric aptasensors for protein disease biomarkers detection: a review
"Available online 24 May 2016"An electrochemical aptasensor is a compact analytical device where the bioreceptor (aptamer) is coupled to a transducer surface to convert a biological interaction into a measurable signal (current) that can be easily processed, recorded and displayed. Since the discovery of the Systematic Evolution of Ligands by Enrichment (SELEX) methodology, the
selection of aptamers and their application as bioreceptors has become a promising tool in the design of electrochemical aptasensors. Aptamers present several advantages that highlight their usefulness as bioreceptors such as chemical stability, cost effectiveness and ease of modification towards detection and immobilization at different transducer surfaces. In this review, a special emphasis is given to the potential use of electrochemical aptasensors for the detection of protein disease biomarkers using voltammetry techniques. Methods for the immobilization of aptamers onto electrode surfaces are discussed, as well as different
electrochemical strategies that can be used for the design of aptasensors.The authors acknowledge the financial support from the Strategic
funding of UID/BIO/04469/2013 unit, from Project POCI-01-0145-
FEDER-006984 â Associate Laboratory LSRE-LCM funded by FEDER
funds through COMPETE2020 - Programa Operacional Competitividade
e Internacionalização (POCI) â and by national funds through FCT -
Fundação para a CiĂȘncia e a Tecnologia and project ref. RECI/BBB-EBI/
0179/2012 (project number FCOMP-01-0124-FEDER-027462) and S.
Meirinhos's doctoral grant (ref SFRH/BD/65021/2009) funded by
Fundação para a CiĂȘncia e a Tecnologia
Applications of Graphene Quantum Dots in Biomedical Sensors
Due to the proliferative cancer rates, cardiovascular diseases, neurodegenerative disorders, autoimmune diseases and a plethora of infections across the globe, it is essential to introduce strategies that can rapidly and specifically detect the ultralow concentrations of relevant biomarkers, pathogens, toxins and pharmaceuticals in biological matrices. Considering these pathophysiologies, various research works have become necessary to fabricate biosensors for their early diagnosis and treatment, using nanomaterials like quantum dots (QDs). These nanomaterials effectively ameliorate the sensor performance with respect to their reproducibility, selectivity as well as sensitivity. In particular, graphene quantum dots (GQDs), which are ideally graphene fragments of nanometer size, constitute discrete features such as acting as attractive fluorophores and excellent electro-catalysts owing to their photo-stability, water-solubility, biocompatibility, non-toxicity and lucrativeness that make them favorable candidates for a wide range of novel biomedical applications. Herein, we reviewed about 300 biomedical studies reported over the last five years which entail the state of art as well as some pioneering ideas with respect to the prominent role of GQDs, especially in the development of optical, electrochemical and photoelectrochemical biosensors. Additionally, we outline the ideal properties of GQDs, their eclectic methods of synthesis, and the general principle behind several biosensing techniques.DFG, 428780268, Biomimetische Rezeptoren auf NanoMIP-Basis zur Virenerkennung und -entfernung mittels integrierter AnsÀtz
Recommended from our members
RNA-aptamers-in-droplets (RAPID) high-throughput screening for secretory phenotypes.
Synthetic biology and metabolic engineering seek to re-engineer microbes into living foundries for the production of high value chemicals. Through a design-build-test cycle paradigm, massive libraries of genetically engineered microbes can be constructed and tested for metabolite overproduction and secretion. However, library generation capacity outpaces the rate of high-throughput testing and screening. Well plate assays are flexible but with limited throughput, whereas droplet microfluidic techniques are ultrahigh-throughput but require a custom assay for each target. Here we present RNA-aptamers-in-droplets (RAPID), a method that greatly expands the generality of ultrahigh-throughput microfluidic screening. Using aptamers, we transduce extracellular product titer into fluorescence, allowing ultrahigh-throughput screening of millions of variants. We demonstrate the RAPID approach by enhancing production of tyrosine and secretion of a recombinant protein in Saccharomyces cerevisiae by up to 28- and 3-fold, respectively. Aptamers-in-droplets affords a general approach for evolving microbes to synthesize and secrete value-added chemicals.Screening libraries of genetically engineered microbes for secreted products is limited by the available assay throughput. Here the authors combine aptamer-based fluorescent detection with droplet microfluidics to achieve high throughput screening of yeast strains engineered for enhanced tyrosine or streptavidin production
Design Strategies of Fluorescent Biosensors Based on Biological Macromolecular Receptors
Fluorescent biosensors to detect the bona fide events of biologically important molecules in living cells are increasingly demanded in the field of molecular cell biology. Recent advances in the development of fluorescent biosensors have made an outstanding contribution to elucidating not only the roles of individual biomolecules, but also the dynamic intracellular relationships between these molecules. However, rational design strategies of fluorescent biosensors are not as mature as they look. An insatiable request for the establishment of a more universal and versatile strategy continues to provide an attractive alternative, so-called modular strategy, which permits facile preparation of biosensors with tailored characteristics by a simple combination of a receptor and a signal transducer. This review describes an overview of the progress in design strategies of fluorescent biosensors, such as auto-fluorescent protein-based biosensors, protein-based biosensors covalently modified with synthetic fluorophores, and signaling aptamers, and highlights the insight into how a given receptor is converted to a fluorescent biosensor. Furthermore, we will demonstrate a significance of the modular strategy for the sensor design
Novel electrochemical aptamer-based sensing mechanism inspired by selection strategies
Des millions de patients souffrant dâinsuffisance cardiaque bĂ©nĂ©ficieraient dâanalyses sanguines hebdomadaires pour surveiller lâĂ©volution de leur Ă©tat de santĂ© comme câest le cas avec les personnes atteintes du diabĂšte. Cependant, il nâexiste pas de technologies dâanalyses sanguines rapides et efficaces pour dĂ©tecter des marqueurs dâinsuffisance cardiaque, telle que la crĂ©atinine, la NT-proBNP et la troponine I par exemple. La possibilitĂ© pour les patients de surveiller leurs taux de crĂ©atinine rĂ©guliĂšrement, du confort de chez soi, amĂ©liorerait largement leur qualitĂ© de vie ainsi que leur taux de survie. En suivant leur taux de crĂ©atinine, le patient pourrait prĂ©dire des signes dâinsuffisance cardiaque, et ainsi faire ajuster leur plan de traitement en consĂ©quence. Pour y arriver, les biocapteurs Ă©lectrochimiques, dont un exemple est le glucomĂštre, reprĂ©sentent une classe prometteuse de dispositifs dâanalyse sanguine puisquâils sont faciles Ă utiliser, rapides, peu coĂ»teux, sensibles, stables et potentiellement universels. Les biocapteurs Ă©lectrochimiques Ă base dâADN pourraient potentiellement ĂȘtre adaptĂ©s en biocapteur de crĂ©atinine, par lâentremise dâaptamĂšres. Le but de cette recherche est de dĂ©velopper un nouveau mĂ©canisme de dĂ©tection universel et efficace pouvant ĂȘtre adaptĂ© directement Ă partir des stratĂ©gies de sĂ©lection des aptamĂšres. Pour ce faire, nous avons identifiĂ© et caractĂ©risĂ© un Ă©lĂ©ment de bioreconnaissance sĂ©lectif pour la crĂ©atinine. Ensuite, nous avons conçu une nouvelle stratĂ©gie de dĂ©tection et nous avons validĂ© cette nouvelle stratĂ©gie par spectroscopie de fluorescence avant de lâadapter pour une dĂ©tection Ă©lectrochimique. Par la suite, nous avons optimisĂ© les performances du biocapteur en modulant des paramĂštres analytiques tels que sa gamme linĂ©aire et son gain de signal, tout en validant ses performances dans une matrice complexe comme le sĂ©rum. Les rĂ©sultats de cette recherche suggĂšrent que la stratĂ©gie de conception du nouveau biocapteur Ă©lectrochimique Ă base dâaptamĂšre est prometteuse pour la dĂ©tection efficace de biomarqueurs sanguins. Ce type de mĂ©canisme pourrait ĂȘtre facilement adaptĂ© pour dĂ©tecter d'autres molĂ©cules cliniquement pertinentes en modifiant simplement la stratĂ©gie de sĂ©lection de l'aptamĂšre.Millions of patients suffering from heart failure would greatly benefit from weekly blood analysis to help them manage their disease state like patients suffering from diabetes. However, no simple blood monitoring technologies detecting heart failure biomarkers, such as creatinine, NT-proBNP, and troponin I, are available. The ability to determine and regularly monitor the creatinine level in the home setting would greatly improve the patientâs quality of life and survival rate. Knowing the concentration of creatinine help to predict heart failure and to revise the treatment plan if the concentration of creatinine is abnormal. To achieve this, electrochemical sensors, like a glucometer, represent a promising class of blood analysis devices due to their ease of use, fast response, low cost, inherent sensitivity and stability, and potential universality. More specifically, DNA-based electrochemical biosensors could potentially be adapted into a creatinine sensor by using aptamers specific to a biomarker. To achieve this goal, we identified a selective biorecognition element for creatinine detection and characterized it. We also designed a novel sensing aptamer-based strategy and validated this strategy by fluorescent spectroscopy before transposing it into the electrochemical format. We then optimized the performance of the sensor by tuning its signal gain and characterizing the dynamic range while also validating its performance in serum. The results of this work suggest that the electrochemical aptamer-based strategy represents a promising sensing mechanism. We believe this mechanism could be easily adapted to detect other clinically relevant molecules by simply relying on the aptamerâs selection strategy
- âŠ