Oligonucleotide Conjugated Gold Nanoparticles Research Articles

Doxorubicin-loaded oligonucleotide conjugated gold nanoparticles: A promising drug delivery system for ovarian cancer

Objective: Major cause of failure in the treatment of advanced ovarian cancer is chemoresistance. Gold nanoparticles (AuNPs) are promising drug delivery systems for overcoming chemoresistance. Doxorubicin (DOX) is one of the representative cancer chemotherapeutic agents and is widely used by many researchers as a chemotherapy agent in the drug delivery system; however, there have been limited data on ovarian cancer research. The aim of our study was to compare cytotoxic effect between DOX and DOX-loaded oligonucleotides (ONTs) attached to gold nanoparticles (AuNPs), called DOA, on ovarian cancer cell lines.

Field detection of multiple RNA viruses/viroids in apple using a CRISPR/Cas12a-based visual assay.

SummaryCo‐infection of apple trees with several viruses/viroids is common and decreases fruit yield and quality. Accurate and rapid detection of these viral pathogens helps to reduce losses and prevent virus spread. Current molecular detection assays used for apple viruses require specialized and expensive equipment. Here, we optimized a CRISPR/Cas12a‐based nucleic acid detection platform for the diagnosis of the most prevalent RNA viruses/viroid in apple, namely Apple necrotic mosaic virus (ApNMV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), Apple chlorotic leaf spot virus (ACLSV) and Apple scar skin viroid (ASSVd). We detected each RNA virus/viroid directly from crude leaf extracts after simultaneous multiplex reverse transcription‐recombinase polymerase amplification (RT‐RPA) with high specificity. Positive results can be distinguished by the naked eye via oligonucleotide‐conjugated gold nanoparticles. The CRISPR/Cas12a‐RT‐RPA platform exhibited comparable sensitivity to RT‐qPCR, with limits of detection reaching 250 viral copies per reaction for ASPV and ASGV and 2500 copies for the others. However, this protocol was faster and simpler, requiring an hour or less from leaf harvest. Field tests showed 100% agreement with RT‐PCR detection for 52 samples. This novel Cas12a‐based method is ideal for rapid and reliable detection of apple viruses in the orchard without the need to send samples to a specialized laboratory.

Doxorubicin-loaded oligonucleotide conjugated gold nanoparticles: A promising drug delivery system for ovarian cancer

Doxorubicin-loaded oligonucleotide conjugated gold nanoparticles: A promising drug delivery system for ovarian cancer

Doxorubicin-loaded oligonucleotide conjugated gold nanoparticles: A promising in vivo drug delivery system for colorectal cancer therapy

In this study, we propose doxorubicin (DOX) loaded oligonucleotides (ONTs) attached to gold nanoparticles (AuNPs) as a drug delivery system for cancer chemotherapy. DOX is one of the representative cancer chemotherapy agents and is widely used by many researchers as a chemotherapy agent in the drug delivery system. Due to the advantages of AuNPs such as simple steps in synthesis, high surface-area-to-volume ratio, and biocompatibility, we utilized AuNPs as drug delivery vehicle. AuNPs were synthesized by chemical reduction to be 13 nm diameter. The G-C rich oligonucleotides were used both for drug loading sites and AuNPs capping agents.80% of DOX in solution could be bound to ONTs on AuNPs to became DOX-loaded AuNPs coated with ONTs (Doxorubicin-Oligomer-AuNP, DOA), and about 28% of loaded DOX was released from the as-prepared DOA. Confocal microscopy observation showed that DOA was well transported into cells, and finally the DOX was released into the cell nucleus. The drug's efficacies such as in vitro cytotoxicity and in vivo tumor growth inhibition were demonstrated with SW480 colon cancer cell line and a xenograft mouse model. MTT assay was performed to see the cytotoxicity effect on SW480 cells treated with DOA for 24 h, and the cell viability was determined to be 41.77% (p < 0.001). When DOA was administered regularly to a tumor bearing mouse, the tumor growth inhibition degree was examined by measuring the tumor size. The treatment-control (T/C) ratio was found to be 0.69. Thus, our results suggest the use of DOAs as promising drug delivery systems for colorectal cancer therapy.

Oligonucleotide-Conjugated Gold Nanoparticles for Application on Lateral Flow Biosensors: Evaluation and Optimization of Low pH and Salt-Aging Conjugation Methods

ABSTRACTPaper-based lateral flow biosensors (LFBs) have been shown to be optimal for rapid analysis, since they exhibit user-friendly format, low analysis times, and no need for specialized instrumentation or highly trained personnel. Low detection limits are desirable for a variety of diagnostic applications, indicating the need for optimal detection labels primarily based on gold nanoparticles. Oligonucleotide-functionalized gold nanoparticles have attained great interest as LFB detection components and study of efficient conjugation methods is ongoing. However, a comparative investigation of oligonucleotide–gold nanoparticle conjugates for application as LFBs has not been performed. Therefore, the goal of the present study was the evaluation of two oligonucleotide–gold nanoparticles conjugation methods, and optimization of the most promising reaction. An LFB for nucleic acids detection was utilized for the evaluation study. Two conjugation protocols were tested: the pH 3 citrate method and the salt-aging method. The prepared conjugates were evaluated in terms of particle color and signal intensity, with a reference oligonucleotide that was used as a model system. Subsequently, the salt-aging protocol, which resulted in better oligonucleotide–gold nanoparticle conjugates, was optimized regarding several reaction parameters. Finally, the conjugate detection sensitivity and reproducibility were assessed.

Gold nanoparticles interfere with sperm functionality by membrane adsorption without penetration

To examine gold nanoparticle reprotoxicity, bovine spermatozoa were challenged with ligand-free or oligonucleotide-conjugated gold nanoparticles synthesized purely without any surfactants by laser ablation. Sperm motility declined at nanoparticle mass dose of 10 µg/ml (corresponding to ∼14 000 nanoparticles per sperm cell) regardless of surface modification. Sperm morphology and viability remained unimpaired at all concentrations. Transmission electron microscopy showed an modification dependant attachment of nanoparticles to the cell membrane of spermatozoa, but provided no evidence for nanoparticle entrance into sperm cells. A molecular examination revealed a reduction of free thiol residues on the cell membrane after nanoparticle exposure, which could explain the decrease in sperm motility. Sperm fertilising ability decreased after exposure to 10 µg/ml of ligand-free nanoparticles indicating that agglomerated ligand-free nanoparticles interfere with membrane properties necessary for fertilisation. In conclusion, nanoparticles may impair key sperm functions solely by interacting with the sperm surface membrane.

Developing oligonucleotide microarray-based resonance light scattering assay for DNA detection on the PAMAM dendrimer modified surface

Here, a three-dimensional (3D) oligonucleotide microarray-based resonance light scattering (RLS) assay has been developed for DNA detection. Oligonucleotide conjugated gold nanoparticles are used as RLS probes for labeling the detection system, followed by silver deposition for signal enhancement. The 3D oligonucleotide microarray is fabricated on the home-made fourth-generation (G4) NH2-terminated poly(amidoamine) dendrimers (PAMAM) modified substrate. After activated by glutaraldehyde (GA), the PAMAM modified substrate enables to react with NH2-modified oligonucleotide with highly efficiency and generates highly signal-to-background ratio. This assay makes it possible to discriminate an oligonucleotide sequence from the target with single nucleotide mismatch with high selectivity. And detection sensitivity of the 3D microarray is nearly 3-fold higher than that of two-dimensional (2D) microarray which is fabricated on the commercial planar slide. The discrimination between G : T and C : T mismatch as well as the mismatch sites, a particularly difficult task for microarray-based assays, has also evaluated.

Synthesis of Polynucleotide Modified Gold Nanoparticles as a High Potent Anti‐Cancer Drug Carrier

AbstractGold nanoparticles have been developed for the photoacoustic imaging, delivery of genes and laser induced photothermal therapy. In this study, we have developed oligonucleotide conjugated gold nanoparticles as the carrier for simultaneous DNA and anti‐cancer nucleoside delivery. The polynucleotidenanoparticle complex presented higher capacity in carrying 5‐FU anti‐cancer compounds than the original gold particles. The hydrodynamic size of the gold nanoparticles increased from 25 to 35 nm with an increase in the negative surface charge from −9.58 to 21.66 mV after polynucleotide conjugation and drug loading. A positive association between environmental pH and drug release was observed in PBS, which implied their potential use in the controlled localized drug release in the lower GI tract. The MTT assay revealed dose dependent cytotoxicity to colon cancer cell line than free compounds. These results suggest the potential use of this new polynucleotide‐gold nanoparticles complex as the environmental controlled anti‐cancer nanocapsule, especially suitable for per oral colon cancer chemotherapy.

DNA-Based Programmed Assembly of Gold Nanoparticles on Lithographic Patterns with Extraordinary Specificity

We demonstrate the highly specific and programmed assembly of oligonucleotide-conjugated gold nanoparticles on lithographically defined microscale gold patterns. A key feature of our fabrication technique is the use of poly(ethylene glycol) (PEG) groups to form an inert coating on regions of the chip where no nanoparticle assembly is desired. By assembling multiple layers of DNA-conjugated nanoparticles we illustrate the capability of PEG surface coatings to exquisitely direct the nanoparticles onto the lithographic patterns with almost zero nonspecific reaction per square micron. We further suggest that the use of PEG to eliminate nonspecific reaction may be extended to micro- and nanoscale fabrication systems that make use of a variety of different nanostructures.

Oligonucleotide-functionalized gold nanoparticles as probes in a dry-reagent strip biosensor for DNA analysis by hybridization.

The highly specific molecular recognition properties of oligonucleotides are combined with the unique optical properties of gold nanoparticles for the development of a dry-reagent strip-type biosensor that enables visual detection of double stranded DNA within minutes. The assay does not require instrumentation and avoids the multiple incubation and washing steps performed in most current assays. Gold nanoparticle reporters with oligo(dT) attached to their surface form an integral part of the strip. Biotinylated PCR products (233 bp or 495 bp) are hybridized (5 min) with a poly(dA)-tailed oligo and applied on the strip, which is then immersed in the appropriate buffer. As the buffer migrates upward, it rehydrates the nanoparticles that are linked to the target DNA through poly(dA)/(dT) hybridization. Capture of the hybrids by immobilized streptavidin in the test zone of the strip generates a characteristic red band. A second red band is formed, by hybridization, in the control zone of the strip to indicate proper test performance. The sensor offers at least 8 times higher detectability than ethidium bromide staining of agarose gels and provides confirmation of the amplified fragments. Quantitative data are obtained by densitometric analysis of the bands. As low as 2 fmol of amplified DNA were detectable by the strip sensor. Also, 500 copies of prostate-specific antigen cDNA were detected by combining PCR and the strip sensor. The sensor was used successfully for detection of hepatitis C virus in plasma samples from 20 patients. The strip detected 16 out of 16 positive samples and gave no signal for 4 samples that were negative for the virus. To our knowledge, this is the first dry-reagent system that makes use of oligonucleotide-conjugated gold nanoparticles as probes.