A highly sensitive electrochemical aptasensor for cocaine detection based on CRISPR-Cas12a and terminal deoxynucleotidyl transferase as signal amplifiers.

Cocaine is one of the mainly used illegal drugs in the world. Using the signal amplification elements of terminal deoxynucleotidyl transferase (TdT) and CRISPR-Cas12a, a highly sensitive and simple electrochemical aptasensor was introduced for cocaine quantification. When, no cocaine existed in the sample, the 3'-end of complementary strand of aptamer (CS) was extended by TdT, leading to the activation of CRISPR-Cas12a and remaining of very short oligonucleotides on the working electrode.

A bivalent binding aptamer-cDNA on MoS nanosheets based fluorescent aptasensor for detection of aflatoxin M.

To ensure the safety of dairy products, especially milk, and consequently protect human health, accurate and simple analytical techniques are highly necessary to determine the low concentration of aflatoxin M (AFM) as an important carcinogen. Herein, a novel, accurate and simple fluorescent aptasensor was designed for selective detection of AFM based on bivalent binding aptamer-cDNA (BBA-cDNA) structure. Moreover, MoS nanosheets (MoS NSs) were used as the fluorescent quencher and FAM-labeled complementary strand of aptamer (FAM-CS) was applied as a fluorescent probe.

An optical aptasensor for aflatoxin M1 detection based on target-induced protection of gold nanoparticles against salt-induced aggregation and silica nanoparticles.

Not only intoxications of aflatoxins are significant risk for human beings, but also; the contamination with these toxins affect the economy. Therefore, developing a rapid, precise and inexpensive determination method is vitally important. Here, a colorimetric aptasensor is introduced for the detection of aflatoxin M (AFM) based on the preservation of gold nanoparticles (AuNPs) against NaCl-induced aggregation by detaching of complementary strand of aptamer (CS) from the aptamer-modified streptavidin coated silica nanoparticles (SNPs) following the addition of target.

Co-delivery of doxorubicin and aptamer against Forkhead box M1 using chitosan-gold nanoparticles coated with nucleolin aptamer for synergistic treatment of cancer cells.

Herein, a nanotherapeutic delivery method was presented for co-delivery of doxorubicin (DOX) and aptamer against Forkhead box M1 (FOXM1 Apt) to cancer cells. Firstly, the vehicle composed of chitosan (CS)-Gold nanoparticles (AuNPs) conjugate was prepared. Nucleolin aptamer (AS1411) and FOXM1 Apt were loaded onto the CS-AuNPs and formed Aptamers (Apts)-CS-AuNPs.

A smart ATP-responsive chemotherapy drug-free delivery system using a DNA nanostructure for synergistic treatment of breast cancer and .

This study demonstrated a chemotherapy drug-free delivery system for breast cancer treatment based on a simple DNA nanostructure composed of sequence 1 containing ATP and AS1411 aptamers and sequence 2 containing antimiR-21. The DNA nanostructure was used for co-delivery of KLA peptide and antimiR-21 as antiapoptotic agents. These therapeutic agents could not be internalised into eukaryotic cells freely which is one of the great features of this targeting platform.

An ultrasensitive electrochemical sensing method for detection of microcystin-LR based on infinity-shaped DNA structure using double aptamer and terminal deoxynucleotidyl transferase.

This study develops a novel electrochemical sensing platform for microcystin-LR (MC-LR) detection. This aptasensor comprises the hybridization of double aptamer to its complementary strand (CS) on the surface of electrode and generation of an Infinity-shaped DNA structure in the absence of target by terminal deoxynucleotidyl transferase (TdT). The formation of Infinity-shaped construction leads to the development of an ultrasensitive aptasensor for MC-LR detection.

A rapid and simple ratiometric fluorescent sensor for patulin detection based on a stabilized DNA duplex probe containing less amount of aptamer-involved base pairs.

In this study, a sensor is described for determination of patulin by using ratiometric fluorescence measurement and strand displacement strategy. In the presence of patulin, the ratiometric fluorescence response decreases, owing to disassembly of DNA duplex structure and target-mediated release of TAMRA-labeled complementary DNA sequence2 (cDNA2). While, in the absence of target, the fluorescence resonance energy transfer (FRET) phenomenon happens between FAM and TAMRA under excitation at 490 nm, resulting in the enhancement of ratiometric signal.

Fluorescent sensor for detection of miR-141 based on target-induced fluorescence enhancement and PicoGreen.

Studies have shown that microRNAs affect the development of tumors. In many cases, they can be applied as biomarkers for the diagnosis of cancer; therefore, simple and sensitive analytical methods for detection of miRNAs are necessary. In this study, miR-141, which is used to diagnose several types of cancer, was detected in water and serum samples using a biosensor designed based on streptavidin-coated magnetic beads (SMBs), complementary sequences of miR-141 and PicoGreen as the fluorescent dye.

Design, synthesis and biological evaluation of novel benzo- and tetrahydrobenzo-[h]quinoline derivatives as potential DNA-intercalating antitumor agents.

A new series of benzo- and tetrahydro benzo-[h]quinoline bearing a flexible (dimethylamino)ethylcarboxamide side chain was designed and synthesized as DNA-intercalating antitumor agents. The cytotoxic activity of the synthesized compounds was evaluated against four human cancer cell lines including MCF-7, A2780, C26 and A549. In general, saturated quinolines (tetrahydrobenzo[h]quinolines) exhibited more cytotoxicity compared to their corresponding unsaturated quinolines (benzo[h]quinolines).

A label-free fluorescent aptasensor for detection of kanamycin based on dsDNA-capped mesoporous silica nanoparticles and Rhodamine B.

Kanamycin is an aminoglycoside antibiotic that can be useful against both gram negative and positive bacteria. However, if its serum levels are not controlled properly, it can cause serious side effects like ototoxicity and nephrotoxicity. The aim of this study was to design a simple and rapid fluorescent aptasensor for detection of kanamycin, based on Aptamer/Complementary strand (dsDNA)-capped mesoporous silica nanoparticles (MSNs) and Rhodamine B as a fluorescent probe.

A colorimetric gold nanoparticle aggregation assay for malathion based on target-induced hairpin structure assembly of complementary strands of aptamer.

The authors describe a method for the colorimetric determination of the pesticide malathion. It is based on the use of a hairpin structure consisting of a complementary strand of aptamer and a double-stranded DNA (dsDNA) structure to protect gold nanoparticles (AuNPs) against salt-induced aggregation. In the absence of malathion, the dsDNA structure is preserved on the surface of AuNPs and the color of the AuNPs in solutions containing NaCl remains red.

Double targeting and aptamer-assisted controlled release delivery of epirubicin to cancer cells by aptamers-based dendrimer in vitro and in vivo.

Clinical use of epirubicin (Epi) in the treatment of cancer has been limited, due to its cardiotoxicity. Targeted delivery of chemotherapeutic agents could increase their efficacy and reduce their off-target effects. High drug loading and excellent stability of DNA dendrimers make these DNA nanostructures unique candidates for biological applications.

Double targeting, controlled release and reversible delivery of daunorubicin to cancer cells by polyvalent aptamers-modified gold nanoparticles.

Clinical use of daunorubicin (Dau) in treatment of leukemia has been restricted because of its cardiotoxicity. Targeted delivery of anticancer drugs could decrease their off-target effects and enhance their efficacy. In this study a modified polyvalent aptamers (PA)-Daunorubicin (Dau)-Gold nanoparticles (AuNPs) complex was designed and its efficacy was assessed in Molt-4 cells (human acute lymphoblastic leukemia T-cell, target).

Synthesis, Characterization and Fluorescence Properties of Zn(II) and Cu(II) Complexes: DNA Binding Study of Zn(II) Complex.

Zinc(II) and copper(II) complexes containing Schiff base, 2- methoxy-6((E)-(phenylimino) methyl) phenol ligand (HL) were synthesized and characterized by elemental analysis, IR, NMR, and single crystal X-ray diffraction technique. The fluorescence properties and quantum yield of zinc complex were studied. Our data showed that Zn complex could bind to DNA grooves with Kb = 10(4) M(-1).

Colorimetric and fluorescence quenching aptasensors for detection of streptomycin in blood serum and milk based on double-stranded DNA and gold nanoparticles.

Antibiotic residues in animal foodstuffs are of great concern to consumers. In this study, fluorescence quenching and colorimetric aptasensors were designed for detection of streptomycin based on aqueous gold nanoparticles (AuNPs) and double-stranded DNA (dsDNA). In the absence of streptomycin, aptamer/FAM-labeled complementary strand dsDNA is stable, resulting in the aggregation of AuNPs by salt and an obvious color change from red to blue and strong emission of fluorescence.

An aptasensor for selective, sensitive and fast detection of lead(II) based on polyethyleneimine and gold nanoparticles.

Lead (Pb), as a major environmental contaminant, could be harmful to humans when inhaled or ingested. In this study, we developed a sensitive, selective and fast colorimetric aptasensor for Pb(+2) based on polyethylenimine (PEI) and gold nanoparticles (AuNPs). In the absence of Pb(+2), aptamer binds to PEI.

Targeted and controlled release delivery of daunorubicin to T-cell acute lymphoblastic leukemia by aptamer-modified gold nanoparticles.

Clinical administration of daunorubicin (Dau) in treatment of leukemia has been limited by its cardiotoxicity. Targeted delivery of chemotherapy drugs could reduce their side effects and increase the therapeutic efficacy of these drugs. Biocompatibility and large surface area of gold nanoparticles (AuNPs) make these nanoparticles great candidates for biomedical applications.

A novel colorimetric triple-helix molecular switch aptasensor for ultrasensitive detection of tetracycline.

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.

Epirubicin loaded super paramagnetic iron oxide nanoparticle-aptamer bioconjugate for combined colon cancer therapy and imaging in vivo.

Every year a large number of new cases of colorectal cancer are diagnosed in the world. Application of Epirubicin (Epi) in treatment of cancer has been limited due to its cardiotoxicity. Specific delivery of chemotherapy drugs is an important factor in reducing the side effects of drugs used in chemotherapy.

Reversible targeting and controlled release delivery of daunorubicin to cancer cells by aptamer-wrapped carbon nanotubes.

Aim: Single-walled carbon nanotubes (SWNTs) have been already used as drug carriers. In this study, we introduced sgc8c aptamer (this aptamer targets leukemia biomarker protein tyrosine kinase-7) to complex between Dau (daunorubicin) and SWNT to enhance targeted delivery of Dau to acute lymphoblastic leukemia T-cells (Molt-4).

Material And Methods: Dau-aptamer-SWNTs tertiary complex formation was analyzed by visible spectroscopy and spectrofluorophotometric analysis.