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Aptamer-antibody dual probes on single-walled carbon nanotube bridged dielectrode: Comparative analysis on human blood clotting factor

Yao J, Li S, Zhang L, Yang Y, Gopinath SCB, Lakshmipriya T, et al.

Int J Biol Macromol, 2020 May 15;151:1133-1138.
PMID: 31743722 DOI: 10.1016/j.ijbiomac.2019.10.156

Haemophilia is a blood clotting disorder known as 'Christmas disease' caused when the blood has defect with the clotting factor(s). Bleeding leads various issues, such as chronic pain, arthritis and a serious complication during the surgery. Identifying this disease is mandatory to take the necessary treatment and maintains the normal clotting. It has been proved that the level of factor IX (FIX) is lesser with haemophilia patient and the attempt here is focused to quantify FIX level by interdigitated electrode (IDE) sensor. Single-walled carbon nanotube (SWCNT) was utilized to modify IDE sensing surface. On this surface, dual probing was evaluated with aptamer and antibody to bring the possible advantages. The detection limit with antibody was found to be 1 pM, while aptamer shows 100 fM. Further, a fine-tuning was attempted with sandwich pattern of aptamer-FIX-antibody and antibody-FIX-aptamer and compared. Specific elevation of detection with 10 folds was noticed and displayed the detection at 100 f. in both sandwich patterns. In addition, FIX was detected in the diluted human serum by aptamer-FIX-antibody sandwich, it was found that FIX detected from the dilution factor 1:640. A novel demonstration is with higher discrimination against other clotting factors, XI and VII.

Matched MeSH terms: Molecular Probes*
Fulltext Polymerase chain reaction detection and restriction enzyme typing of human papillomavirus in cervical carcinoma

Yadav M, Nurhayati ZA, Padmanathan A, Abdul Aziz Y, Norhanom AW

Med J Malaysia, 1995 Mar;50(1):64-71.
PMID: 7752979

Specific human papillomavirus (HPV) types have been implicated in the development of cervical carcinoma worldwide. Novel molecular techniques have facilitated the detection and typing of HPV in cervical lesions. DNA preparations from a series of 23 histopathologically confirmed cervical carcinoma patients were analyzed by polymerase chain reaction (PCR) using degenerate primers for the presence of HPV DNA sequences. A total of 22 of 23 cases studied (95.7%) were found positive for HPV DNA sequences. Further studies by DNA hybridization with viral specific probe and restriction enzyme analysis demonstrated the presence of HPV 16 in 73.9% (17/23) and HPV 18 in 65.2% (15/23) of the cases examined. Interestingly, the uncommon HPV 31 and 33 were also found but with a lower percentage (16.9%). It was noted that HPV 16 frequency in the carcinoma increased with age but HPV 18 was evenly present at all ages investigated. We found that HPV was frequently associated with the majority of the cervical carcinomas, and in all but one case, oncogenic high risk HPV genotypes were present. We conclude that HPV infection of the genital tract has an important role in the development of the disease in Malaysia.

Matched MeSH terms: Molecular Probes/genetics
Electrospin-coating of nitrocellulose membrane enhances sensitivity in nucleic acid-based lateral flow assay

Yew CT, Azari P, Choi JR, Li F, Pingguan-Murphy B

Anal Chim Acta, 2018 Jun 07;1009:81-88.
PMID: 29422135 DOI: 10.1016/j.aca.2018.01.016

Point-of-care biosensors are important tools developed to aid medical diagnosis and testing, food safety and environmental monitoring. Paper-based biosensors, especially nucleic acid-based lateral flow assays (LFA), are affordable, simple to produce and easy to use in remote settings. However, the sensitivity of such assays to infectious diseases has always been a restrictive challenge. Here, we have successfully electrospun polycaprolactone (PCL) on nitrocellulose (NC) membrane to form a hydrophobic coating to reduce the flow rate and increase the interaction rate between the targets and gold nanoparticles-detecting probes conjugates, resulting in the binding of more complexes to the capture probes. With this approach, the sensitivity of the PCL electrospin-coated test strip has been increased by approximately ten-fold as compared to the unmodified test strip. As a proof of concept, this approach holds great potential for sensitive detection of targets at point-of-care testing.

Matched MeSH terms: Molecular Probes/chemistry
Synthesis of triazole-linked oligonucleotides with high affinity to DNA complements and an analysis of their compatibility with biosystems

Varizhuk AM, Kaluzhny DN, Novikov RA, Chizhov AO, Smirnov IP, Chuvilin AN, et al.

J Org Chem, 2013 Jun 21;78(12):5964-9.
PMID: 23724994 DOI: 10.1021/jo400651k

New oligonucleotide analogues with triazole internucleotide linkages were synthesized, and their hybridization properties were studied. The analogues demonstrated DNA binding affinities similar to those of unmodified oligonucleotides. The modification was shown to protect the oligonucleotides from nuclease hydrolysis. The modified oligonucleotides were tested as PCR primers. Modifications remote from the 3'-terminus were tolerated by polymerases. Our results suggest that these new oligonucleotide analogues are among the most promising triazole DNA mimics characterized to date.

Matched MeSH terms: Molecular Probes/chemical synthesis*
Synthesis of fluorescent carbon dots via simple acid hydrolysis of bovine serum albumin and its potential as sensitive sensing probe for lead (II) ions

Wee SS, Ng YH, Ng SM

Talanta, 2013 Nov 15;116:71-6.
PMID: 24148375 DOI: 10.1016/j.talanta.2013.04.081

Carbon dots have great potential to be utilised as an optical sensing probe due to its unique photoluminescence and less toxic properties. This work reports a simple and novel synthesis method of carbon dots via direct acid hydrolysis of bovine serum albumin protein in a one-pot approach. Optimisation of the important synthetic parameters has been performed which consists of temperature effect, acid to protein ratio and kinetics of reaction. Higher temperature has promoted better yield with shorter reaction time. The carbon dots obtained shows a strong emission at the wavelength of 400 nm with an optimum excitation of 305 nm. The potential of the carbon dots as optical sensing probe has been investigated on with different cations that are of environmental and health concern. The fluorescence of the carbon dots was significantly quenched particularly by lead (II) ions in a selective manner. Further analytical study has been performed to leverage the performance of the carbon dots for lead (II) ions sensing using the standard Stern-Volmer relationship. The sensing probe has a dynamic linear range up to 6.0 mM with a Stern-Volmer constant of 605.99 M(-1) and a limit of detection (LOD) of 5.05 μM. The probe performance was highly repeatable with a standard deviation below 3.0%. The probe suggested in this study demonstrates the potential of a more economical and greener approach that uses protein based carbon dots for sensing of heavy metal ions.

Matched MeSH terms: Molecular Probes/chemical synthesis*; Molecular Probes/chemistry
Metal-Polydopamine Framework as an Effective Fluorescent Quencher for Highly Sensitive Detection of Hg(II) and Ag(I) Ions through Exonuclease III Activity

Ravikumar A, Panneerselvam P, Morad N

ACS Appl Mater Interfaces, 2018 Jun 20;10(24):20550-20558.
PMID: 29792319 DOI: 10.1021/acsami.8b05041

In this paper, we propose a metal-polydopamine (MPDA) framework with a specific molecular probe which appears to be the most promising approach to a strong fluorescence quencher. The MPDA framework quenching ability toward various organic fluorophore such as aminoethylcoumarin acetate, 6-carboxyfluorescein (FAM), carboxyteramethylrhodamine, and Cy5 are used to establish a fluorescent biosensor that can selectively recognize Hg2+ and Ag+ ions. The fluorescent quenching efficiency was sufficient to achieve more than 96%. The MPDA framework also exhibits different affinities with ssDNA and dsDNA. In addition, the FAM-labeled ssDNA was adsorbed onto the MPDA framework, based on their interaction with the complex formed between MPDA frameworks/ssDNA taken as a sensing platform. By taking advantage of this sensor, highly sensitive and selective determination of Hg2+ and Ag+ ions is achieved through exonuclease III signal amplification activity. The detection limits of Hg2+ and Ag+ achieved to be 1.3 and 34 pM, respectively, were compared to co-existing metal ions and graphene oxide-based sensors. Furthermore, the potential applications of this study establish the highly sensitive fluorescence detection targets in environmental and biological fields.

Matched MeSH terms: Molecular Probes
Integrated miniature fluorescent probe to leverage the sensing potential of ZnO quantum dots for the detection of copper (II) ions

Ng SM, Wong DS, Phung JH, Chin SF, Chua HS

Talanta, 2013 Nov 15;116:514-9.
PMID: 24148438 DOI: 10.1016/j.talanta.2013.07.031

Quantum dots are fluorescent semiconductor nanoparticles that can be utilised for sensing applications. This paper evaluates the ability to leverage their analytical potential using an integrated fluorescent sensing probe that is portable, cost effective and simple to handle. ZnO quantum dots were prepared using the simple sol-gel hydrolysis method at ambient conditions and found to be significantly and specifically quenched by copper (II) ions. This ZnO quantum dots system has been incorporated into an in-house developed miniature fluorescent probe for the detection of copper (II) ions in aqueous medium. The probe was developed using a low power handheld black light as excitation source and three photo-detectors as sensor. The sensing chamber placed between the light source and detectors was made of 4-sided clear quartz windows. The chamber was housed within a dark compartment to avoid stray light interference. The probe was operated using a microcontroller (Arduino Uno Revision 3) that has been programmed with the analytical response and the working algorithm of the electronics. The probe was sourced with a 12 V rechargeable battery pack and the analytical readouts were given directly using a LCD display panel. Analytical optimisations of the ZnO quantum dots system and the probe have been performed and further described. The probe was found to have a linear response range up to 0.45 mM (R(2)=0.9930) towards copper (II) ion with a limit of detection of 7.68×10(-7) M. The probe has high repeatable and reliable performance.

Matched MeSH terms: Molecular Probes/chemistry*
Fulltext Alzheimer's Disease Determination by a Dual Probe on Gold Nanourchins and Nanohorn Hybrids

Qiu Z, Shen Q, Jiang C, Yao L, Sun X, Li J, et al.

Int J Nanomedicine, 2021;16:2311-2322.
PMID: 33776435 DOI: 10.2147/IJN.S302396

Background: Alzheimer's disease (AD) is a neurodegenerative chronic disorder that causes dementia and problems in thinking, cognitive impairment and behavioral changes. Amyloid-beta (Aβ) is a peptide involved in AD progression, and a high level of Aβ is highly correlated with severe AD. Identifying and quantifying Aβ levels helps in the early treatment of AD and reduces the factors associated with AD.
Materials and Methods: This research introduced a dual probe detection system involving aptamers and antibodies to identify Aβ. Aptamers and antibodies were attached to the gold (Au) urchin and hybrid on the carbon nanohorn-modified surface. The nanohorn was immobilized on the sensor surface by using an amine linker, and then a Au urchin dual probe was immobilized.
Results: This dual probe-modified surface enhanced the current flow during Aβ detection compared with the surface with antibody as the probe. This dual probe interacted with higher numbers of Aβ peptides and reached the detection limit at 10 fM with R2=0.992. Furthermore, control experiments with nonimmune antibodies, complementary aptamer sequences and control proteins did not display the current responses, indicating the specific detection of Aβ.
Conclusion: Aβ-spiked artificial cerebrospinal fluid showed a similar response to current changes, confirming the selective identification of Aβ.

Matched MeSH terms: Molecular Probes/chemistry*
Fulltext Synthesis of [18F]F-γ-T-3, a Redox-Silent γ-Tocotrienol (γ-T-3) Vitamin E Analogue for Image-Based In Vivo Studies of Vitamin E Biodistribution and Dynamics

Roselt P, Cullinane C, Noonan W, Elsaidi H, Eu P, Wiebe LI

Molecules, 2020 Dec 03;25(23).
PMID: 33287202 DOI: 10.3390/molecules25235700

Vitamin E, a natural antioxidant, is of interest to scientists, health care pundits and faddists; its nutritional and biomedical attributes may be validated, anecdotal or fantasy. Vitamin E is a mixture of tocopherols (TPs) and tocotrienols (T-3s), each class having four substitutional isomers (α-, β-, γ-, δ-). Vitamin E analogues attain only low concentrations in most tissues, necessitating exacting invasive techniques for analytical research. Quantitative positron emission tomography (PET) with an F-18-labeled molecular probe would expedite access to Vitamin E's biodistributions and pharmacokinetics via non-invasive temporal imaging. (R)-6-(3-[18F]Fluoropropoxy)-2,7,8-trimethyl-2-(4,8,12-trimethyltrideca-3,7,11-trien-1-yl)-chromane ([18F]F-γ-T-3) was prepared for this purpose. [18F]F-γ-T-3 was synthesized from γ-T-3 in two steps: (i) 1,3-di-O-tosylpropane was introduced at C6-O to form TsO-γ-T-3, and (ii) reaction of this tosylate with [18F]fluoride in DMF/K222. Non-radioactive F-γ-T-3 was synthesized by reaction of γ-T-3 with 3-fluoropropyl methanesulfonate. [18F]F-γ-T-3 biodistribution in a murine tumor model was imaged using a small-animal PET scanner. F-γ-T-3 was prepared in 61% chemical yield. [18F]F-γ-T-3 was synthesized in acceptable radiochemical yield (RCY 12%) with high radiochemical purity (>99% RCP) in 45 min. Preliminary F-18 PET images in mice showed upper abdominal accumulation with evidence of renal clearance, only low concentrations in the thorax (lung/heart) and head, and rapid clearance from blood. [18F]F-γ-T-3 shows promise as an F-18 PET tracer for detailed in vivo studies of Vitamin E. The labeling procedure provides acceptable RCY, high RCP and pertinence to all eight Vitamin E analogues.

Matched MeSH terms: Molecular Probes/pharmacokinetics; Molecular Probes/chemistry
Fluorescence in situ hybridization analysis using PAX8- and PPARG-specific probes reveals the presence of PAX8-PPARG translocation and 3p25 aneusomy in follicular thyroid neoplasms

Chia WK, Sharifah NA, Reena RM, Zubaidah Z, Clarence-Ko CH, Rohaizak M, et al.

Cancer Genet. Cytogenet., 2010 Jan 1;196(1):7-13.
PMID: 19963130 DOI: 10.1016/j.cancergencyto.2009.08.001

At the present time, the differentiation between follicular thyroid carcinoma (FTC) and adenoma can be made only postoperatively and is based on the presence of capsular or vascular invasion. The ability to differentiate preoperatively between the malignant and benign forms of follicular thyroid tumors assumes greater importance in any clinical setting. The PAX8-PPARG translocation has been reported to occur in the majority of FTC. In this study, a group of 60 follicular thyroid neoplasms [18 FTC, 1 Hurthle cell carcinoma (HCC), 24 follicular thyroid adenomas (FTA), 5 Hurthle cell adenomas (HCA), and 12 follicular variants of papillary thyroid carcinomas (FV-PTC)] were analyzed to determine the prevalence of the PAX8-PPARG translocation by fluorescence in situ hybridization. The PAX8-PPARG translocation was detected in 2/18 FTC (11.1%). In addition, 2/18 (11.1%) FTC and 1/5 (20%) HCA showed 3p25 aneusomy only. The frequency of the translocation detected in the study was lower compared to the earlier studies conducted in Western countries. This might be attributed to the ethnic background and geographic location. Detection of either the PAX8-PPARG translocation or the 3p25 aneusomy in FTC indicates that these are independent genetic events. It is hereby concluded that 3p25 aneusomy or PAX8-PPARG translocation may play an important role in the molecular pathogenesis of follicular thyroid tumors.

Matched MeSH terms: Molecular Probes
Conformational properties of serum albumin binding sites in rats with different behaviour in the open field test

Gryzunov YA, Koplik EV, Smolina NV, Kopaeva LB, Dobretsov GE, Sudakov KV

Stress, 2006 Mar;9(1):53-60.
PMID: 16753933

In this study, the hypothesis was tested that behaviour of rats under the open field test condition and effects of subsequent acute stress relate to conformational properties of the main plasma carrier protein, albumin.To evaluate albumin properties, fluorescence intensity of a molecular probe CAPIDAN (N-carboxyphenylimide of dimethylaminonaphthalic acid) at N (at pH 7.4) and F (at pH 4.2) albumin conformations was measured and the N-F signal ratio was calculated. The data obtained showed that CAPIDAN fluoresces selectively from albumin in rat serum and its fluorescence is sensitive to binding of fatty acids and some other ligands to albumin. Behaviour of 78 Wistar male rats was characterized from the fraction of time taken for exploratory and ambulatory activity during the open field test. In rats not subjected to stress (n = 40), a negative correlation was revealed between open field activity and CAPIDAN N-to-F ratio for albumin (r = - 0.55, p < 0.0005). In the group of rats subjected to acute stress (immobilization plus stochastic electrocutaneous stimulation) the correlation between behavioural activity and the albumin conformational properties was significantly positive (r = 0.59, p < 0.0001): the CAPIDAN albumin fluorescence ratio increased in the highly active rats and decreased in the low-activity rats. The mechanisms of the observed effects may involve differences in nonesterified fatty acid production during stress.

Matched MeSH terms: Molecular Probes

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