Displaying publications 1 - 20 of 57 in total

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  1. Targeting genetic tool for long non-coding RNA of cancer stem cells with aptamer-guided nanocarriers
    Zaiki Y, Wong TW
    Expert Opin Drug Deliv, 2021 12;18(12):1791-1793.
    PMID: 34605336 DOI: 10.1080/17425247.2021.1989408
    Matched MeSH terms: Aptamers, Nucleotide*
  2. Formulation of DNA chimera templates: Effects on emission behavior of silver nanoclusters and sensing
    Lee ST, Beaumont D, Su XD, Muthoosamy K, New SY
    Anal Chim Acta, 2018 Jun 20;1010:62-68.
    PMID: 29447672 DOI: 10.1016/j.aca.2018.01.012
    Single strand DNA (ssDNA) chimeras consisting of a silver nanoclusters-nucleating sequence (NC) and an aptamer are widely employed to synthesize functional silver nanoclusters (AgNCs) for sensing purpose. Despite its simplicity, this chimeric-templated AgNCs often leads to undesirable turn-off effect, which may suffer from false positive signals caused by interference. In our effort to elucidate how the relative position of NC and aptamer affects the fluorescence behavior and sensing performance, we systematically formulated these NC and aptamer regions at different position in a DNA chimera. Using adenosine aptamer as a model, we tested the adenosine-induced optical response of each design. We also investigated the effect of linker region connecting NC and aptamer, as well as different NC sequence on the sensing performance. We concluded that locating NC sequence at 5'-end exhibited the best response, with immediate fluorescence enhancement observed over a wide linear range (1-2500 μM). Our experimental findings help to explain the emission behavior and sensing performance of chimeric conjugates of AgNCs, providing an important means to formulate a better aptasensor.
    Matched MeSH terms: Aptamers, Nucleotide/chemistry
  3. Aptamers: an emerging class of bioaffinity ligands in bioactive peptide applications
    Acquah C, Agyei D, Obeng EM, Pan S, Tan KX, Danquah MK
    Crit Rev Food Sci Nutr, 2020;60(7):1195-1206.
    PMID: 30714390 DOI: 10.1080/10408398.2018.1564234
    The food and health applications of bioactive peptides have grown remarkably in the past few decades. Current elucidations have shown that bioactive peptides have unique structural arrangement of amino acids, conferring distinct functionalities, and molecular affinity characteristics. However, whereas interest in the biological potency of bioactive peptides has grown, cost-effective techniques for monitoring the structural changes in these peptides and how these changes affect the biological properties have not grown at the same rate. Due to the high binding affinity of aptamers for other biomolecules, they have a huge potential for use in tracking the structural, conformational, and compositional changes in bioactive peptides. This review provides an overview of bioactive peptides and their essential structure-activity relationship. The review further highlights on the types and methods of synthesis of aptamers before the discussion of the prospects, merits, and challenges in the use of aptamers for bioaffinity interactions with bioactive peptides.
    Matched MeSH terms: Aptamers, Nucleotide/chemical synthesis*; Aptamers, Nucleotide/chemistry*
  4. Unravelling the diagnostic and therapeutic potentialities of a novel RNA aptamer isolated against human pituitary tumour transforming gene 1 (PTTG1) protein
    Prabu SS, Ch'ng ES, Woon PY, Chen JH, Tang TH, Citartan M
    Anal Chim Acta, 2020 Nov 22;1138:181-190.
    PMID: 33161980 DOI: 10.1016/j.aca.2020.09.038
    Human Pituitary Tumour Transforming Gene 1 (PTTG1) is an oncoprotein involved in maintaining chromosome stability and acts as a biomarker for a panel of cancers. In this study, we endeavoured to generate an RNA aptamer against PTTG1. The RNA aptamer, SECURA-3 has an estimated equilibrium dissociation constant of 16.41 ± 6.4 nM. The aptamer was successfully harnessed in several diagnostic platforms including ELASA, aptamer-based dot blot and aptamer-based western blot. SECURA-3 was also unveiled as a potential probe that could replace its counterpart antibody in the histostaining-based detection of PTTG1 in HeLa and MCF-7 formalin-fixed paraffin-embedded cell blocks. In the aspect of therapeutics, SECURA-3 RNA aptamer demonstrates an antagonistic effect by antagonizing the interaction between PTTG1 and CXCR2, as revealed in the in vitro competitive nitrocellulose filter binding assay and dual-luciferase reporter assay in HeLa cells. As the first anti-PTTG1 aptamer, SECURA-3 RNA aptamer has immense diagnostic and therapeutic properties.
    Matched MeSH terms: Aptamers, Nucleotide*
  5. Regulation of Glycine Cleavage and Detoxification by a Highly Conserved Glycine Riboswitch in Burkholderia spp
    Munyati-Othman N, Appasamy SD, Damiri N, Emrizal R, Alipiah NM, Ramlan EI, et al.
    Curr Microbiol, 2021 Aug;78(8):2943-2955.
    PMID: 34076709 DOI: 10.1007/s00284-021-02550-5
    The glycine riboswitch is a known regulatory element that is unique in having two aptamers that are joined by a linker region. In this study, we investigated a glycine riboswitch located in the 5' untranslated region of a glycine cleavage system homolog (gcvTHP) in Burkholderia spp. Structure prediction using the sequence generated a model with a glycine binding pocket composed of base-triple interactions (G62-A64-A86 and G65-U84-C85) that are supported by A/G minor interactions (A17-C60-G88 and G16-C61-G87, respectively) and two ribose-zipper motifs (C11-G12 interacting with A248-A247 and C153-U154 interacting with A79-A78) which had not been previously reported. The capacity of the riboswitch to bind to glycine was experimentally validated by native gel assays and the crucial role of interactions that make up the glycine binding pocket were proven by mutations of A17U and G16C which resulted in conformational differences that may lead to dysfunction. Using glycine supplemented minimal media, we were able to prove that the expression of the gcvTHP genes found downstream of the riboswitch responded to the glycine concentrations introduced thus confirming the role of this highly conserved Burkholderia riboswitch and its associated genes as a putative glycine detoxification system in Burkholderia spp.
    Matched MeSH terms: Aptamers, Nucleotide*
  6. Recent developments of aptasensors expedient for point-of-care (POC) diagnostics
    Citartan M, Tang TH
    Talanta, 2019 Jul 01;199:556-566.
    PMID: 30952298 DOI: 10.1016/j.talanta.2019.02.066
    Aptamers are nucleic acid-based molecular recognition elements that are specific and have high binding affinity against their respective targets. On account of their target recognition capacity, aptamers are widely utilized in a number of applications including diagnostics. This review aims to highlight the recent developments of aptasensors expedient for point-of-care (POC) diagnostics. Significant focus is given on the primary assay formats of aptamers such as fluorescence, electrochemical, surface plasmon resonance (SPR) and colorimetric assays. A potpourri of platforms such as paper-based device, lateral flow assay, portable electrodes, portable SPR and smart phones expedient for point-of-care (POC) diagnostics are discussed. Emphasis is also given on the technicalities and assay configurations associated with the sensors.
    Matched MeSH terms: Aptamers, Nucleotide/chemical synthesis; Aptamers, Nucleotide/chemistry*
  7. In vitro selection and characterization of single stranded DNA aptamers for luteolin: A possible recognition tool
    Tuma Sabah J, Zulkifli RM, Shahir S, Ahmed F, Abdul Kadir MR, Zakaria Z
    Anal Biochem, 2018 05 15;549:72-79.
    PMID: 29524380 DOI: 10.1016/j.ab.2018.03.004
    Distinctive bioactivities possessed by luteolin (3', 4', 5, 7-tetrahydroxy-flavone) are advantageous for sundry practical applications. This paper reports the in vitro selection and characterization of single stranded-DNA (ssDNA) aptamers, specific for luteolin (LUT). 76-mer library containing 1015 randomized ssDNA were screened via systematic evolution of ligands by exponential enrichment (SELEX). The recovered ssDNA pool from the 8th round was amplified with unlabeled primers and cloned into PSTBlue-1 vector prior to sequencing. 22 of LUT-binding aptamer variants were further classified into one of the seven groups based on their N40 random sequence regions, wherein one representative from each group was characterized. The dissociation constant of aptamers designated as LUT#28, LUT#20 and LUT#3 was discerned to be 107, 214 and 109 nM, respectively with high binding affinity towards LUT. Prediction analysis of the secondary structure suggested discrete features with typical loop and stem motifs. Furthermore, LUT#3 displayed higher specificity with insignificant binding toward kaempferol and quercetin despite its structural and functional similarity compared to LUT#28 and LUT#20. Further LUT#3 can detect free luteolin within 0.2-1 mM in solution. It was suggested that LUT#3 aptamer were the most suitable for LUT recognition tool at laboratory scale based on the condition tested.
    Matched MeSH terms: Aptamers, Nucleotide/chemical synthesis; Aptamers, Nucleotide/chemistry
  8. Deploying aptameric sensing technology for rapid pandemic monitoring
    Acquah C, Danquah MK, Agyei D, Moy CK, Sidhu A, Ongkudon CM
    Crit Rev Biotechnol, 2016 Dec;36(6):1010-1022.
    PMID: 26381238
    The genome of virulent strains may possess the ability to mutate by means of antigenic shift and/or antigenic drift as well as being resistant to antibiotics with time. The outbreak and spread of these virulent diseases including avian influenza (H1N1), severe acute respiratory syndrome (SARS-Corona virus), cholera (Vibrio cholera), tuberculosis (Mycobacterium tuberculosis), Ebola hemorrhagic fever (Ebola Virus) and AIDS (HIV-1) necessitate urgent attention to develop diagnostic protocols and assays for rapid detection and screening. Rapid and accurate detection of first cases with certainty will contribute significantly in preventing disease transmission and escalation to pandemic levels. As a result, there is a need to develop technologies that can meet the heavy demand of an all-embedded, inexpensive, specific and fast biosensing for the detection and screening of pathogens in active or latent forms to offer quick diagnosis and early treatments in order to avoid disease aggravation and unnecessary late treatment costs. Nucleic acid aptamers are short, single-stranded RNA or DNA sequences that can selectively bind to specific cellular and biomolecular targets. Aptamers, as new-age bioaffinity probes, have the necessary biophysical characteristics for improved pathogen detection. This article seeks to review global pandemic situations in relation to advances in pathogen detection systems. It particularly discusses aptameric biosensing and establishes application opportunities for effective pandemic monitoring. Insights into the application of continuous polymeric supports as the synthetic base for aptamer coupling to provide the needed convective mass transport for rapid screening is also presented.
    Matched MeSH terms: Aptamers, Nucleotide*
  9. SELEX Modifications and Bioanalytical Techniques for Aptamer-Target Binding Characterization
    Tan SY, Acquah C, Sidhu A, Ongkudon CM, Yon LS, Danquah MK
    Crit Rev Anal Chem, 2016 Nov;46(6):521-37.
    PMID: 26980177 DOI: 10.1080/10408347.2016.1157014
    The quest to improve the detection of biomolecules and cells in health and life sciences has led to the discovery and characterization of various affinity bioprobes. Libraries of synthetic oligonucleotides (ssDNA/ssRNA) with randomized sequences are employed during Systematic Evolution of Ligands by Exponential Enrichment (SELEX) to select highly specific affinity probes called aptamers. With much focus on the generation of aptamers for a variety of target molecules, conventional SELEX protocols have been modified to develop new and improved SELEX protocols yielding highly specific and stable aptamers. Various techniques have been used to analyze the binding interactions between aptamers and their cognate molecules with associated merits and limitations. This article comprehensively reviews research advancements in the generation of aptamers, analyses physicochemical conditions affecting their binding characteristics to cellular and biomolecular targets, and discusses various field applications of aptameric binding. Biophysical techniques employed in the characterization of the molecular and binding features of aptamers to their cognate targets are also discussed.
    Matched MeSH terms: Aptamers, Nucleotide/chemistry*
  10. In silico approach for Post-SELEX DNA aptamers: A mini-review
    Ahmad NA, Mohamed Zulkifli R, Hussin H, Nadri MH
    J Mol Graph Model, 2021 06;105:107872.
    PMID: 33765525 DOI: 10.1016/j.jmgm.2021.107872
    Aptamers are short oligonucleotides that possess high specificity and affinity against their target. Generated via Systematic Evolution of Ligands by Exponential Enrichment, (SELEX) in vitro, they were screened and enriched. This review covering the study utilizing bioinformatics tools to analyze primary sequence, secondary and tertiary structure prediction, as well as docking simulation for various aptamers and their ligand interaction. Literature was pooled from Web of Science (WoS) and Scopus databases until December 18, 2020 using specific search string related to DNA aptamers, in silico, structure prediction, and docking simulation. Out of 330 published articles, 38 articles were assessed in the analysis based on the predefined inclusion and exclusion criteria. It was found that Mfold and RNA Composer web server is the most popular tool in secondary and tertiary structure prediction of DNA aptamers, respectively. Meanwhile, in docking simulation, ZDOCK and AutoDock are preferred to analyze binding interaction in the aptamer-ligand complex. This review reports a brief framework of recent developments of in silico approaches that provide predictive structural information of ssDNA aptamer.
    Matched MeSH terms: Aptamers, Nucleotide*
  11. Nucleic Acid Aptamers as a Potential Nucleus Targeted Drug Delivery System
    Shrivastava G, Bakshi HA, Aljabali AA, Mishra V, Hakkim FL, Charbe NB, et al.
    Curr Drug Deliv, 2020;17(2):101-111.
    PMID: 31906837 DOI: 10.2174/1567201817666200106104332
    BACKGROUND: Nucleus targeted drug delivery provides several opportunities for the treatment of fatal diseases such as cancer. However, the complex nucleocytoplasmic barriers pose significant challenges for delivering a drug directly and efficiently into the nucleus. Aptamers representing singlestranded DNA and RNA qualify as next-generation highly advanced and personalized medicinal agents that successfully inhibit the expression of certain proteins; possess extraordinary gene-expression for manoeuvring the diseased cell's fate with negligible toxicity. In addition, the precisely directed aptamers to the site of action present a tremendous potential to reach the nucleus by escaping the ensuing barriers to exhibit a better drug activity and gene expression.

    OBJECTIVE: This review epigrammatically highlights the significance of targeted drug delivery and presents a comprehensive description of the principal barriers faced by the nucleus targeted drug delivery paradigm and ensuing complexities thereof. Eventually, the progress of nucleus targeting with nucleic acid aptamers and success achieved so far have also been reviewed.

    METHODS: Systematic literature search was conducted of research published to date in the field of nucleic acid aptamers.

    CONCLUSION: The review specifically points out the contribution of individual aptamers as the nucleustargeting agent rather than aptamers in conjugated form.

    Matched MeSH terms: Aptamers, Nucleotide*
  12. Generation of an RNA aptamer against LipL32 of Leptospira isolated by Tripartite-hybrid SELEX coupled with in-house Python-aided unbiased data sorting
    Shien Yeoh T, Yusof Hazrina H, Bukari BA, Tang TH, Citartan M
    Bioorg Med Chem, 2023 Mar 01;81:117186.
    PMID: 36812779 DOI: 10.1016/j.bmc.2023.117186
    Leptospirosis is a potentially life-threatening zoonosis caused by pathogenic Leptospira. The major hurdle of the diagnosis of Leptospirosis lies in the issues associated with current methods of detection, which are time-consuming, tedious and the need for sophisticated, special equipments. Restrategizing the diagnostics of Leptospirosis may involve considerations of the direct detection of the outer membrane protein, which can be faster, cost-saving and require fewer equipments. One such promising marker is LipL32, which is an antigen with high amino acid sequence conservation among all the pathogenic strains. In this study, we endeavored to isolate an aptamer against LipL32 protein via a modified SELEX strategy known as tripartite-hybrid SELEX, based on 3 different partitioning strategies. In this study, we also demonstrated the deconvolution of the candidate aptamers by using in-house Python-aided unbiased data sorting in examining multiple parameters to isolate potent aptamers. We have successfully generated an RNA aptamer against LipL32 of Leptospira, LepRapt-11, which is applicable in a simple direct ELASA for the detection of LipL32. LepRapt-11 can be a promising molecular recognition element for the diagnosis of leptospirosis by targeting LipL32.
    Matched MeSH terms: Aptamers, Nucleotide*
  13. Isolation of a novel DNA aptamer against LipL32 as a potential diagnostic agent for the detection of pathogenic Leptospira
    Yeoh TS, Tang TH, Citartan M
    Biotechnol J, 2023 Mar;18(3):e2200418.
    PMID: 36426669 DOI: 10.1002/biot.202200418
    Leptospirosis is a potentially life-threatening zoonosis caused by pathogenic Leptospira and for rapid diagnostics, direct detection is desirable. LipL32 protein is the most suitable biomarker for direct detection. DNA aptamers are sought to be generated against LipL32 by Systemic Evolution of Ligands via Exponential Enrichment (SELEX). LepDapt-5a is the most potent aptamer candidate among all the candidates, as determined by direct Enzyme-linked Aptasorbent Assay (ELASA). LepDapt-5a was predicted to form a G-quadruplex structure as predicted by QGRS Mapper and validated experimentally by direct ELASA. The diagnostic potential of the aptamer was further tested on a direct and sandwich ELASA platform. A LOD of 106 mL-1 and 105 mL-1 were estimated by direct and sandwich ELASA platforms, respectively, which are within the range associated with leptospiremia levels. The dot blot assay developed was able to attain a LOD of 104 CFU mL-1 against pathogenic Leptospira, which is also within the leptospiremia level. This is the first-ever DNA aptamer and hybrid-heterodimeric aptamer constructed against LipL32. The diagnostic potentiality of the LepDapt-5a DNA aptamer was proven on three major diagnostic platforms, which are direct ELASA, sandwich ELASA, and aptamer-based dot assay.
    Matched MeSH terms: Aptamers, Nucleotide
  14. Assays for aptamer-based platforms
    Citartan M, Gopinath SC, Tominaga J, Tan SC, Tang TH
    Biosens Bioelectron, 2012 Apr 15;34(1):1-11.
    PMID: 22326894 DOI: 10.1016/j.bios.2012.01.002
    Aptamers are single stranded DNA or RNA oligonucleotides that have high affinity and specificity towards a wide range of target molecules. Aptamers have low molecular weight, amenable to chemical modifications and exhibit stability undeterred by repetitive denaturation and renaturation. Owing to these indispensable advantages, aptamers have been implemented as molecular recognition element as alternative to antibodies in various assays for diagnostics. By amalgamating with a number of methods that can provide information on the aptamer-target complex formation, aptamers have become the elemental tool for numerous biosensor developments. In this review, administration of aptamers in applications involving assays of fluorescence, electrochemistry, nano-label and nano-constructs are discussed. Although detection strategies are different for various aptamer-based assays, the core of the design strategies is similar towards reporting the presence of specific target binding to the corresponding aptamers. It is prognosticated that aptamers will find even broader applications with the development of new methods of transducing aptamer target binding.
    Matched MeSH terms: Aptamers, Nucleotide/chemistry*
  15. Cell-targeting aptamers act as intracellular delivery vehicles
    Gopinath SC, Lakshmipriya T, Chen Y, Arshad MK, Kerishnan JP, Ruslinda AR, et al.
    Appl Microbiol Biotechnol, 2016 Aug;100(16):6955-69.
    PMID: 27350620 DOI: 10.1007/s00253-016-7686-2
    Aptamers are single-stranded nucleic acids or peptides identified from a randomized combinatorial library through specific interaction with the target of interest. Targets can be of any size, from small molecules to whole cells, attesting to the versatility of aptamers for binding a wide range of targets. Aptamers show drug properties that are analogous to antibodies, with high specificity and affinity to their target molecules. Aptamers can penetrate disease-causing microbial and mammalian cells. Generated aptamers that target surface biomarkers act as cell-targeting agents and intracellular delivery vehicles. Within this context, the "cell-internalizing aptamers" are widely investigated via the process of cell uptake with selective binding during in vivo systematic evolution of ligands by exponential enrichment (SELEX) or by cell-internalization SELEX, which targets cell surface antigens to be receptors. These internalizing aptamers are highly preferable for the localization and functional analyses of multiple targets. In this overview, we discuss the ways by which internalizing aptamers are generated and their successful applications. Furthermore, theranostic approaches featuring cell-internalized aptamers are discussed with the purpose of analyzing and diagnosing disease-causing pathogens.
    Matched MeSH terms: Aptamers, Nucleotide/metabolism*
  16. Cardiovascular therapies utilizing targeted delivery of nanomedicines and aptamers
    Tan KX, Pan S, Jeevanandam J, Danquah MK
    Int J Pharm, 2019 Mar 10;558:413-425.
    PMID: 30660748 DOI: 10.1016/j.ijpharm.2019.01.023
    Cardiovascular ailments are the foremost trigger of death in the world today, including myocardial infarction and ischemic heart diseases. To date, extraordinary measures have been prescribed, from the perspectives of both conventional medical therapies and surgeries, to enforce cardiac cell regeneration post cardiac traumas, albeit with limited long-term success. The prospects of successful heart transplants are also grim, considering exorbitant costs and unavailability of suitable donors in most cases. From the perspective of cardiac revascularization, use of nanoparticles and nanoparticle mediated targeted drug delivery have garnered substantial attention, attributing to both active and passive heart targeting, with enhanced target specificity and sensitivity. This review focuses on this aspect, while outlining the progress in targeted delivery of nanomedicines in the prognosis and subsequent therapy of cardiovascular disorders, and recapitulating the benefits and intrinsic challenges associated with the incorporation of nanoparticles. This article categorically provides an overview of nanoparticle-mediated targeted delivery systems and their implications in handling cardiovascular diseases, including their intrinsic benefits and encountered procedural trials and challenges. Additionally, the solicitations of aptamers in targeted drug delivery with identical objectives, are presented. This includes a detailed appraisal on various aptamer-navigated nanoparticle targeted delivery platforms in the diagnosis and treatment of cardiovascular maladies. Despite a few impending challenges, subject to additional investigations, both nanoparticles as well as aptamers show a high degree of promise, and pose as the next generation of drug delivery vehicles, in targeted cardiovascular therapy.
    Matched MeSH terms: Aptamers, Nucleotide/administration & dosage*
  17. Aptamer-17β-estradiol-antibody sandwich ELISA for determination of gynecological endocrine function
    Huang Y, Zhang L, Li Z, Gopinath SCB, Chen Y, Xiao Y
    Biotechnol Appl Biochem, 2021 Aug;68(4):881-888.
    PMID: 33245588 DOI: 10.1002/bab.2008
    17β-Estradiol-E2 (17β-E2) is a steroid hormone that plays a major role in the reproductive endocrine system and is involved in various processes, such as pregnancy, fertility, and menopause. In this study, the performance of an enzyme-linked immunosorbent assay (ELISA) for 17β-E2 quantification was enhanced by using a gold nanoparticle (GNP)-conjugated aptamer. An anti-17β-E2-aptamer-GNP antibody was immobilized on an amine-modified ELISA surface. Then, 17β-E2 was allowed to interact with and be sandwiched by antibodies. Aptamer-GNP conjugation was confirmed by colorimetric assays via the naked eye and UV-visible light spectroscopy. The detection limit based on a signal-to-noise ratio (S/N) of 3 was estimated to be 1.5 nM (400 pg/mL), and the linear range was 1.5-50 nM. Control experiments (without 17β-E2/with a complementary aptamer sequence/with a nonimmune antibody) confirmed the specific detection of 17β-E2. Moreover, 17β-E2 spiking of human serum did not interrupt the interaction between 17β-E2 and its antibody and aptamer. Thus, the developed ELISA can be used as an alternate assay for quantification of 17β-E2 and assessment of endocrine-related gynecological problems.
    Matched MeSH terms: Aptamers, Nucleotide/chemistry*
  18. Fulltext Advances in Aptamer-Based Biosensors and Cell-Internalizing SELEX Technology for Diagnostic and Therapeutic Application
    Gan Z, Roslan MAM, Abd Shukor MY, Halim M, Yasid NA, Abdullah J, et al.
    Biosensors (Basel), 2022 Oct 25;12(11).
    PMID: 36354431 DOI: 10.3390/bios12110922
    Aptamers are a group of synthetic single-stranded nucleic acids. They are generated from a random library of single-stranded DNA or RNA by a technology named systematic evolution of ligands by exponential enrichment (SELEX). SELEX is a repetitive process to select and identify suitable aptamers that show high affinity and specificity towards target cells. Great strides have been achieved in the design, construction, and use of aptamers up to this point. However, only a small number of aptamer-based applications have achieved widespread commercial and clinical acceptance. Additionally, finding more effective ways to acquire aptamers with high affinity remains a challenge. Therefore, it is crucial to thoroughly examine the existing dearth and advancement in aptamer-related technologies. This review focuses on aptamers that are generated by SELEX to detect pathogenic microorganisms and mammalian cells, as well as in cell-internalizing SELEX for diagnostic and therapeutic purposes. The development of novel aptamer-based biosensors using optical and electrical methods for microbial detection is reported. The applications and limitations of aptamers are also discussed.
    Matched MeSH terms: Aptamers, Nucleotide*
  19. A Zeolite Nanoparticle-Modified Anionic Surface for Aptasensing Lipocalin-2 in Ulcerative Colitis by Dual-Electrodes
    Li X, Gopinath SCB, Peng X, Lv J
    J Biomed Nanotechnol, 2021 Dec 01;17(12):2495-2504.
    PMID: 34974872 DOI: 10.1166/jbn.2021.3213
    An aptasensor was developed on an interdigitated microelectrode (IDME) by current-volt sensing for the diagnosis of ulcerative colitis by detecting the biomarker lipocalin-2. Higher immobilization of the anti-lipocalin-2 aptamer as a probe was achieved by using sodium dodecyl benzenesulfonate-aided zeolite particles. FESEM and FETEM observations revealed that the size of the zeolite particles was <200 nm, and they displayed a uniform distribution and spherical shape. XPS analysis attested the occurrence of Si, Al, and O groups on the zeolite particles. Zeolite particles were immobilized on IDME by a (3-aminopropyl)-trimethoxysilane amine linker, and then, the aptamer as the probe was tethered on the zeolite particles through a biotin-streptavidin strategy assisted by a bifunctional aldehyde linker. Due to the high occupancy of the aptamer and the efficient electric transfer from zeolite particles, higher changes in current can be observed upon interaction of the aptamer with lipocalin-2. The lower detection of lipocalin-2 was noted as 10 pg/mL, with a linear range from 10 pg/mL to 1 μg/mL and a linear regression equation of y=8E-07x+8E-08; R² = 0.991. Control experiments with complementary aptamer and matrix metalloproteinase-9 indicate the specific detection of lipocalin-2. Furthermore, spiking lipocalin-2 in human serum does not interfere with the identification.
    Matched MeSH terms: Aptamers, Nucleotide*
  20. Cardiovascular biomarker troponin I biosensor: Aptamer-gold-antibody hybrid on a metal oxide surface
    Hui H, Gopinath SCB, Ismail ZH, Chen Y, Pandian K, Velusamy P
    Biotechnol Appl Biochem, 2023 Apr;70(2):581-591.
    PMID: 35765758 DOI: 10.1002/bab.2380
    Myocardial infarction (MI) is highly related to cardiac arrest leading to death and organ damage. Radiological techniques and electrocardiography have been used as preliminary tests to diagnose MI; however, these techniques are not sensitive enough for early-stage detection. A blood biomarker-based diagnosis is an immediate solution, and due to the high correlation of troponin with MI, it has been considered to be a gold-standard biomarker. In the present research, the cardiac biomarker troponin I (cTnI) was detected on an interdigitated electrode sensor with various surface interfaces. To detect cTnI, a capture aptamer-conjugated gold nanoparticle probe and detection antibody probe were utilized and compared through an alternating sandwich pattern. The surface metal oxide morphology of the developed sensor was proven by microscopic assessments. The limit of detection with the aptamer-gold-cTnI-antibody sandwich pattern was 100 aM, while it was 1 fM with antibody-gold-cTnI-aptamer, representing 10-fold differences. Further, the high performance of the sensor was confirmed by selective cTnI determination in serum, exhibiting superior nonfouling. These methods of determination provide options for generating novel assays for diagnosing MI.
    Matched MeSH terms: Aptamers, Nucleotide*
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