Research Institute of science and New Technology

Mashhad, Iran

Research Institute of science and New Technology

Mashhad, Iran

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Abnous K.,Mashhad University of Medical Sciences | Danesh N.M.,Mashhad University of Medical Sciences | Danesh N.M.,Research Institute of science and New Technology | Alibolandi M.,Mashhad University of Medical Sciences | And 2 more authors.
Microchimica Acta | Year: 2017

The authors describe an amperometric aptasensor for the mycotoxin ochrotoxin A (OTA). It is based on the use of a modified gold electrode containing aptamer (Apt) as the sensing ligand, Methylene Blue (MB) as the redox indicator, single-walled carbon nanotubes (SWCNTs) as electrochemical signal amplifiers, and complementary strands of aptamer (CSs) as assisting DNA. In the absence of OTA, the duplex formed between Apt and CSs on the electrode remains intact. Thus, a strong electrochemical signal is observed due to the presence of the redox marker MB in the duplex. If OTA is added, the duplex will be disassembled and MB and SWCNTs will be released from the surface of the gold electrode. Hence, the electrochemical signal is weakened. The method is highly specificity for OTA and has a limit of detection as low as 52 pM. The aptasensor was successfully applied to the determination of OTA in (spiked) serum and grape juice samples where it shows LODs of 134 and 58 pM, respectively. © 2017 Springer-Verlag Wien


Ramezani M.,Mashhad University of Medical Sciences | Mohammad Danesh N.,Mashhad University of Medical Sciences | Mohammad Danesh N.,Research Institute of science and New Technology | Lavaee P.,Academic Center For Education | And 3 more authors.
Biosensors and Bioelectronics | Year: 2015

Detection methods of antibiotic residues in blood serum and animal derived foods are of great interest. In this study a colorimetric aptasensor was designed for sensitive, selective and fast detection of tetracycline based on triple-helix molecular switch (THMS) and gold nanoparticles (AuNPs). As a biosensor, THMS shows distinct advantages including high stability, sensitivity and preserving the selectivity and affinity of the original aptamer. In the absence of tetracycline, THMS is stable, leading to the aggregation of AuNPs by salt and an obvious color change from red to blue. In the presence of tetracycline, aptamer binds to its target, signal transduction probe (STP) leaves the THMS and adsorbs on the surface of AuNPs. So the well-dispersed AuNPs remain stable against salt-induced aggregation with a red color. The presented aptasensor showed high selectivity toward tetracyclines with a limit of detection as low as 266. pM for tetracycline. The designed aptasensor was successfully applied to detect tetracycline in serum and milk. © 2015 Elsevier B.V.


Taghdisi S.M.,Mashhad University of Medical Sciences | Danesh N.M.,Mashhad University of Medical Sciences | Danesh N.M.,Research Institute of science and New Technology | Beheshti H.R.,Testa Quality Control | And 2 more authors.
Nanoscale | Year: 2016

Analytical approaches for the detection and quantitation of ochratoxin A (OTA) in blood serum and food products are high in demand. In this study, a fluorescent aptamer-based sensor (aptasensor) is developed for the selective and sensitive detection of OTA, based on a complementary strand of aptamer (CS) and two types of nanoparticles, gold nanoparticles (AuNPs) and silica nanoparticles (SNPs) coated with streptavidin. The fabricated aptasensor inherits the characteristics of SNPs, as enhancers of fluorescence intensity; AuNPs, such as large surface area and unique optical properties; and high affinity of the aptamer toward its target compared to its CS. In the absence of OTA, no FAM and biotin-labeled CS is in the environment of the SNPs coated with streptavidin, which leads to no fluorescence emission. In the presence of the target, an FAM and biotin-labeled CS-SNPs coated with streptavidin conjugate is formed, thus resulting in a very strong fluorescence emission. The designed fluorescent aptasensor exhibits high selectivity toward OTA with a limit of detection (LOD) as low as 0.098 nM. Furthermore, the fabricated aptasensor was successfully applied for the detection of OTA in grape juice and serum with LODs of 0.113 and 0.152 nM, respectively. © 2016 The Royal Society of Chemistry.


Abnous K.,Mashhad University of Medical Sciences | Danesh N.M.,Mashhad University of Medical Sciences | Danesh N.M.,Research Institute of science and New Technology | Ramezani M.,Research Institute of science and New Technology | And 2 more authors.
Biosensors and Bioelectronics | Year: 2016

Analytical methods for detection and quantitation of chloramphenicol in blood serum and foodstuffs arse highly in demand. In this study, a colorimetric sandwich aptamer-based sensor (aptasensor) was fabricated for sensitive and selective detection of chloramphenicol, based on an indirect competitive enzymefree assay using gold nanoparticles (AuNPs), biotin and streptavidin. The designed aptasensor acquires characteristics of AuNPs, including large surface area and unique optical properties, and strong interaction of biotin with streptavidin. In the absence of chloramphenicol, the sandwich structure of aptasensor forms, leading to the observation of sharp red color. In the presence of target, functionalized AuNPs could not bind to 96-well plates, resulting in a faint red color. The fabricated colorimetric aptasensor exhibited high selectivity toward chloramphenicol with a limit of detection as low as 451 pM. Moreover, the developed colorimetric aptasensor was successfully used to detect chloramphenicol in milk and serum with LODs of 697 and 601 pM, respectively. © 2015 Elsevier B.V. Allrights reserved.


Danesh N.M.,Mashhad University of Medical Sciences | Danesh N.M.,Research Institute of science and New Technology | Ramezani M.,Mashhad University of Medical Sciences | Emrani A.S.,Mashhad University of Medical Sciences | And 2 more authors.
Biosensors and Bioelectronics | Year: 2016

Detection and quantitation of antibiotic residues in blood serum and animal foodstuffs are of great significance. In this study, an electrochemical aptasensor was developed for sensitive and selective detection of streptomycin, based on exonuclease I (Exo I), complimentary strand of aptamer (CS), Archshape structure of aptamer (Apt)-CS conjugate and gold electrode. The designed aptasensor inherits characteristics of gold including large surface area and high electrochemical conductivity, as well as high sensitivity and selectivity of aptamer toward its target, property of Arch-shape structure of Apt-CS conjugate to act as a gate and barrier for the access of redox probe to the surface of electrode and the function of Exo I as an enzyme which selectively digests the 3'-end of single stranded DNA (ssDNA). In the absence of streptomycin the gate remains closed. Thus, the electrochemical signal is weak. Upon addition of streptomycin, the Apt leaves the CS and binds to streptomycin and the Arch-shape structure is disassembled. Then, Exo I addition leads to a strong electrochemical signal. The designed electrochemical aptasensor exhibited high selectivity toward streptomycin with a limit of detection (LOD) as low as 11.4 nM. Moreover, the developed electrochemical aptasensor was successfully used to detect streptomycin in milk and serum with LODs of 14.1 and 15.3 nM, respectively. © 2015 Elsevier B.V. Allrights reserved.


Taghdisi S.M.,Mashhad University of Medical Sciences | Danesh N.M.,Mashhad University of Medical Sciences | Danesh N.M.,Research Institute of science and New Technology | Ramezani M.,Mashhad University of Medical Sciences | Abnous K.,Mashhad University of Medical Sciences
RSC Advances | Year: 2016

Clinical application of vincristine in treatment of cancer is restricted because of its poor solubility and neuropathy. Targeted delivery of cytotoxic drugs could improve their therapeutic efficacy and reduce their severe side effects. Biocompatibility and high accumulation of human serum albumin nanoparticles (HSA) in tumors make this substance an ideal candidate for biomedical usage. Here, a Vincristine-HSA-Sgc8c aptamer (Apt) complex was designed and assessed for the treatment of Molt-4 cells (human acute lymphoblastic leukemia T-cell, target). Vincristine-HSA conjugate and Vincristine-HSA-Apt complex formations were analyzed by particle size analyzer, transmission electron microscopy (TEM) and gel retardation assay. Internalization of the Vincristine-HSA-FAM (3′-fluorescein)-labeled Apt complex into Molt-4 (target) and U266 cells (B lymphocyte human myeloma, nontarget) was monitored by confocal imaging and flow cytometry analysis. For cell viability (MTT assay), both cell lines were treated with vincristine, Vincristine-HSA conjugate, HSA-Apt conjugate and Vincristine-HSA-Apt complex. Vincristine was efficiently loaded (8.5%) into HSA. The results of confocal imaging and flow cytometry analysis indicated that the Vincristine-HSA-FAM-labeled Apt complex was effectively internalized into target cells (Molt-4) but not into nontarget cells (U266). The results of MTT assay also confirmed the internalization data. The Vincristine-HSA-Apt complex had less cytotoxicity in U266 cells compared to vincristine alone and Vincristine-HSA conjugate. In conclusion, the developed drug delivery system acquired properties of high drug loading, high cancer cell accumulation and cancer cell targeting. © 2016 The Royal Society of Chemistry.


Taghdisi S.M.,Mashhad University of Medical Sciences | Danesh N.M.,Mashhad University of Medical Sciences | Danesh N.M.,Research Institute of science and New Technology | Ramezani M.,Mashhad University of Medical Sciences | Abnous K.,Mashhad University of Medical Sciences
Biosensors and Bioelectronics | Year: 2016

Analytical techniques for detection and quantitation of tetracyclines in food products are greatly in demand. In this study, a novel electrochemical aptasensor was designed for ultrasensitive and selective detection of tetracyclines, based on M-shape structure of aptamer (Apt)-complementary strands of aptamer (CSs) complex, exonuclease I (Exo I) and gold electrode. The aptasensor was developed to make a noticeable electrochemical difference in the absence and presence of tetracycline. In the absence of tetracycline, the M-shape structure, which acts as a gate and barrier for the access of redox probe to the surface of gold electrode remains intact, leading to a weak electrochemical signal. Upon addition of tetracycline, Apt leaves CSs, resulting in disassembly of M-shape structure and following the addition of Exo I, a strong electrochemical signal was observed. The developed analytical assay indicated high selectivity toward tetracycline with a limit of detection (LOD) as low as 450 pM. Moreover, the designed aptasensor was effectively used for the detection of tetracycline in milk and serum samples with LODs of 740 and 710 pM, respectively. © 2016 Elsevier B.V.


Taghdisi S.M.,Mashhad University of Medical Sciences | Danesh N.M.,Mashhad University of Medical Sciences | Danesh N.M.,Research Institute of science and New Technology | Ramezani M.,Mashhad University of Medical Sciences | And 2 more authors.
Biosensors and Bioelectronics | Year: 2016

Monitoring of myoglobin (Mb) in human blood serum is highly in demand for early diagnosis of acute myocardial infarction (AMI). Here, a novel electrochemical aptasensor was developed for ultrasensitive and selective detection of Mb, based on Y-shape structure of dual-aptamer (DApt)-complementary strand of aptamer (CS) conjugate, gold electrode and exonuclease I (Exo I). The designed aptasensor obtains features of gold, such as high electrochemical conductivity and large surface area, property of Y-shape structure of DApt-CS conjugate to function as a gate and obstacle for the access of redox probe to the surface of electrode, as well as high specificity and sensitivity of aptamer toward its target and Exo I as an enzyme which specifically degrades the 3'-end of single-stranded DNA (ssDNA). In the absence of Mb, the Y-shape structure remains intact. So, a weak electrochemical signal is observed. Upon addition of target, the DApt leave the CS and bind to Mb, leading to disassembly of Y-shape structure and following the addition of Exo I, a strong electrochemical signal could be recorded. The fabricated aptasensor showed high selectivity toward Mb with a limit of detection (LOD) as low as 27 pM. Besides, the developed aptasensor was effectively applied to detect Mb in human serum. © 2016 Elsevier B.V.


Emrani A.S.,Mashhad University of Medical Sciences | Danesh N.M.,Mashhad University of Medical Sciences | Danesh N.M.,Research Institute of science and New Technology | Ramezani M.,Mashhad University of Medical Sciences | And 2 more authors.
Biosensors and Bioelectronics | Year: 2016

Cocaine is one of the most commonly misused stimulant which could influence the central nervous system. In this study, a fluorescent aptamer-based sensor (aptasensor) was designed for sensitive and selective detection of cocaine, based on hairpin structure of complementary strand of aptamer (CS), target-induced release of aptamer (Apt) from CS and two kinds of nanoparticles, including silica nanoparticles (SNPs) coated with streptavidin and gold nanoparticles (AuNPs). The designed aptasensor acquires characteristics of AuNPs such as unique optical properties and large surface area, SNPs as amplifiers of fluorescence intensity, higher affinity of Apt toward its target relative to its CS, and finally the hairpin structure of CS that brings the fluorophore (FAM) to close proximity to the surface of SNPs. In the absence of cocaine, FAM is in close proximity to the surface of AuNPs, resulting in a weak fluorescence emission. In the presence of target, FAM comes to close proximity to the surface of SNPs because of the formation of hairpin structure of CS, leading to a very strong fluorescence emission. The fabricated fluorescent aptasensor exhibited a good selectivity toward cocaine with a limit of detection (LOD) as low as 209 pM. Moreover, the designed aptasensor was successfully utilized to detect cocaine in serum with a LOD as low as 293 pM. © 2015 Elsevier B.V.


Abnous K.,Mashhad University of Medical Sciences | Danesh N.M.,Mashhad University of Medical Sciences | Danesh N.M.,Research Institute of science and New Technology | Ramezani M.,Mashhad University of Medical Sciences | And 2 more authors.
Sensors and Actuators, B: Chemical | Year: 2016

Cocaine is one of the most commonly abused stimulant which could affect the central nervous system. In this work, an electrochemical aptasensor was designed for sensitive and selective detection of cocaine, based on complimentary strands of aptamer (CSs), H-shape structure of Aptamer (Apt)-CSs conjugate and gold electrode. This aptasensor inherits properties of gold such as high electrochemical conductivity and large surface area, as well as high selectivity and sensitivity of aptamer toward its target and property of H-shape structure of Apt-CSs conjugate to act as a gate for the access of redox probe to the surface of electrode. In the absence of cocaine, the gate is closed, so that the electrochemical signal is weak. In the presence of cocaine, aptamer binds to target, leaves the surface of electrode and the gate is opened, leading to a strong electrochemical signal. The fabricated electrochemical aptasensor exhibited good selectivity toward cocaine with a limit of detection (LOD) as low as 0.228 nM. Furthermore, the designed aptasensor was successfully used to detect cocaine in serum with a LOD as low as 0.273 nM. © 2015 Elsevier B.V. All rights reserved.

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