Antibody-conjugated Gold Nanoparticles Research Articles

Targeted highly sensitive detection/eradication of multi-drug resistant Salmonella DT104 through gold nanoparticle-SWCNT bioconjugated nanohybrids.

Monoclonal antibody-conjugated sphere-shaped gold nanoparticles were combined with single-walled carbon nanotubes (SWCNTs) to create a nanohybrid system to selectively detect and eradicate multiple drug resistant Salmonella (MDRS) typhimurium DT104 bacteria. The Raman signal intensity from Rhodamine 6G (Rh6G) modified monoclonal AC04 antibody SWCNTs-gold nanoparticle (SWCNT-GNPs) hybrid provided a SERS enhancement by several orders of magnitude to detect the MDRS bacteria over the GNP system. A targeted photothermolysis experiment using 670 nm light at 2 W cm(-2) for 15 min, resulted in selective and irreparable damage to more than 99% Salmonella DT104 at the concentration of 10(5) CFU mL(-1). In comparison to solely SWCNTs or GNPs, our SWCNT-GNPs nanohybrids have also shown a better photothermal efficiency.

Incubation-free electrochemical immunoassay for diethylstilbestrol in milk using gold nanoparticle-antibody conjugates for signal amplification

We report on a novel enzyme-enhanced label for the electrochemical determination of diethylstilbestrol (DES). The label was obtained by orientation-controlled immobilization of a multiplex horseradisch peroxidase (HRP) conjugated polymer on gold nanoparticles (AuNPs) using the Envision reagent (EV) which is an enzyme-polymer complex that contains HRP and anti-IgG antibody in a polydextrin amine skeleton. The AuNPs were modified with Concanavalin A (Con A) and served as a carrier for immobilization of the EV−DES antibody composite. This resulted in a bioconjugate of the type AuNP−Con A−EV−DES Ab which was employed as the label. On exposure to samples containing DES, a sandwich immunocomplex is formed between antibody against DES (which was immobilized on a glassy carbon electrode and is acting as a capture probe), DES (the analyte), and the above label as the signal tracer. Hemin was used as an electronic mediator in the reaction of HRP. The HRP on the label catalyzes the oxidative formation of hydrogen peroxide at pH 7.0, and this induces an increased reductive current in the presence of hemin as an electron mediator. Under optimal conditions, the current increases linearly with increasing concentrations of DES in the range from 5 to 500 pg · mL−1, with a detection limit as low as 2 pg · mL−1 (at an S/N of 3). The method exhibits high selectivity and good stability. It works without incubation so that the time for an assay is shortened to 5 min. The assays was successfully applied to the determination of DES in milk samples.

Study on synthesis of colloidal gold nanoparticles and preparation of antiE. coli O157 monoclonal antibody conjugated nanoparticles

The present paper describes the preparation of colloidal gold nanoparticles by a chemical reduction method, using some chemical compounds such as sodium citrate (Na3Ct), chloroauric acid (HAuCl4.3H2O) and anti-E. coli O157 monoclonal antibodyconjugated gold nanoparticles. The nanoparticles were characterized by several techniques including Ultraviolet and Visible Absorption Spectroscopy (UV-Vis), Transmission Electron Microscopy (TEM). The UV-Vis confirmed that the concentration of Na3Ct has a major effect on the size of the synthesized gold nanoparticles, and TEM images showed that the size of gold particles is in the range of 10-20 nm. In addition, the binding of the antibody-gold conjugates to E. coli O157 was also investigated using the same characterization means

Rapid quantitative immunochromatographic strip for multiple proteins test

A rapid quantitative immunochromatographic strip (IS) for simultaneous detection of multiple proteins was described. Rabbit IgG (R-IgG) and human IgM (H-IgM) were used as model protein targets for demonstration of the proof of concepts. Gold nanoparticles (Au-NP) were used as tags to label the anti-R-IgG and anti-H-IgM antibodies to form two kinds of gold nanoparticle-antibody conjugates, respectively. The mixture of above conjugates was dispensed on the conjugate pad of IS. Capture antibodies of IgG and IgM were dispensed in the different locations of nitrocellulose membrane of the IS to form two test zones. The multiplex immunoassay was performed by simply applying the sample solution on the IS, waiting for several minutes, two red bands at the test zones can be easily discriminated with eyes. For quantitative test, the captured Au-NP tags on the test zones were quantified with a portable strip reader by recording the intensities of the resulting red bands at the test zones. The detection limits were estimated to be 0.5 and 2.5ng/ml for R-IgG and H-IgM, respectively, in association with a 7-min immunoassay time.

The Development of a Label-Free Electrochemical Impedance Based Pointof-care Technology for Multimarker Detection

With an increasing global population, rising healthcare costs, and greater demand on hospitals and clinicians, a growing need for low cost, rapid, Point of Care Technologies (POCT) exists. The overall goal is to detect or monitor a disease in order to give patients and clinicians fast, accurate, and all-encompassing information regarding the state of the disease. A challenge for many currentpoint-of-care technologies is the difficulty of monitoring several biomarkers simultaneously without the complexity of multiple sensors, labels, or spatially separated transducers. We have previously shown that convoluted signals obtained from protein biomarkers monitored by electrochemical impedance spectroscopy can be “tuned” away from one another by conjugation with gold nanoparticles to allow for the potential simultaneous detection of multiple biomarkers. This method of detection yields a sensitive and specific means of biomarker quantification in human media including tears or blood. In this work, we detail the development of a mathematical model that explores the roles of various factors, such as nanoparticle size and the nature of materials, so that a design space could be created for tuningotherwise convoluted biomarkers. Furthermore, we present assessments as to the validity of this model with preliminary bench-top experiments by taking advantage of gold nanoparticle-antibody conjugates of varying sizes. Gold nanoparticle size changes of 5, 10, and 20 nm demonstrated a 10.0, 4.8, and 1.0 Hz shift in frequency, respectively. Future work includes exploration of different sensor configurations, continuous monitoring, and the prospect for implantable sensors were also discussed as potential future avenues.

Automation Highlights from the Literature

Automation Highlights from the Literature

Poster 61: Induction of Selective Apoptosis by Means of Anti-HER2 Antibody-Conjugated Gold Nanoparticles on Melanoma Cell

Poster 61: Induction of Selective Apoptosis by Means of Anti-HER2 Antibody-Conjugated Gold Nanoparticles on Melanoma Cell

Stability of antibody-conjugated gold nanoparticles in the endolysosomal nanoenvironment: implications for noninvasive radiofrequency-based cancer therapy

The use of noninvasive radiofrequency (RF) electric fields as an energy source for thermal activation of nanoparticles within cancer cells could be a valuable addition to the emerging field of nano-mediated cancer therapies. Based on investigations of cell death through hyperthermia, and offering the ability for total-body penetration by RF fields, this technique is thought to complement and possibly outperform existing nano-heat treatments that utilize alternative heat production via optical or magnetic stimuli. However, it remains a challenge to understand fully the complex RF-nanoparticle-intracellular interactions before full system optimization can be engineered. Herein we have shown that liver cancer cells can selectively internalize antibody-conjugated gold nanoparticles (AuNPs) through receptor-mediated endocytosis, with the nanoparticles predominantly accumulating and aggregating within cytoplasmic endolysosomes. After exposure to an external RF field, nonaggregated AuNPs absorbed and dissipated energy as heat, causing thermal damage to the targeted cancer cells. We also observed that RF absorption and heat dissipation is dependent on solubility of AuNPs in the colloid, which is pH dependent. Furthermore, by modulating endolysosomal pH it is possible to prevent intracellular AuNP aggregation and enhance thermal cytotoxicity in hepatocellular cancer cells. From the Clinical EditorGold nanoparticles absorb energy from RF fields and can exert hyperthermic effects leading to cell death. Combining this known effect with antibody-based targeting of the nanoparticles, selective cancer specific hyperthermia induced cell death therapies can be designed, as demonstrated in this article.

Anti-CD30-targeted gold nanoparticles for photothermal therapy of L-428 Hodgkin's cell

PurposeDue to the efficient bioconjugation and highly photothermal effect, gold nanoparticles can stain receptor-overexpressing cancer cells through specific targeting of ligands to receptors, strongly absorb specific light and efficiently convert it into heat based on the property of surface plasmon resonance, and then induce the localized protein denaturation and cell death.MethodsTwo gold nanoparticle–antibody conjugates, gold-BerH2 antibody (anti-CD30 receptor) and gold-ACT1 antibody (anti-CD25-receptor), were synthesized. Gold-BerH2 conjugates can specifically bind to the surface of L-428 Hodgkin’s cells, and gold-ACT1 conjugates were used for the control. The gold nanoparticle-induced L-428 cell-killing experiments were implemented with different experimental parameters.ResultsAt a relatively low concentration of gold and short incubation time, the influence of cytotoxicity of gold on cell viability can be overlooked. Under laser irradiation at suitable power, the high killing efficiency of gold-targeted L-428 cells was achieved, but little damage was done to nontargeted cancer cells.ConclusionGold nanoparticle-mediated photothermal therapy provides a relatively safe therapeutic technique for cancer treatment.

A mass spectrometry-based immunosensor for bacteria using antibody-conjugated gold nanoparticles

We have developed a simple mass spectrometry-based immunosensor using antibody (Ab)-modified gold nanoparticles (Ab-Au NPs) for the rapid quantitation of bacteria via the analysis of Au clusters under pulsed laser irradiation.

VEGFR-2 targeted cellular delivery of doxorubicin by gold nanoparticles for potential antiangiogenic therapy

We report a novel gold nanobioconjugate system that achieves targeted delivery of the small molecule drug doxorubicin to endothelial cells using anti-VEGFR-2 antibody conjugated gold nanoparticles (GNPs). The reported nanobioconjugate system combines the inherent ability of GNPs to undergo high levels of derivatization with the precision of antibody recognition of a cell surface antigen. Transmission electron microscopy (TEM) and surface-enhanced Raman spectroscopy (SERS) confirmed intracellular presence of the GNPs. Using a VEGFR-2 expressing cell line and a cell line that is negative for the receptor, in combination with competition assay we established the cell specific targeted delivery of the nanobioconjugate. The nanobioconjugate system described here may have potential drug delivery applications for antiangiogenic cancer therapy.

An enhanced immuno-dot blot assay for the detection of white spot syndrome virus in shrimp using antibody conjugated gold nanoparticles probe

White Spot Syndrome (WSS) is a worldwide ailment of penaeid shrimp, a lethal and contagious disease in shrimp caused by the White Spot Syndrome Virus (WSSV). It is essential to control; handle early findings and routine screenings under field conditions. Though PCR affirmed sensing of the causative viral nucleic acid has many advantages, for its routine use custom necessitate an advanced equipment and technical expertise. In comparison, protein-based immuno detecting methods are easier to perform by a commoner, but lack of sensitivity due to inadequate signal amplification. In this study, we focused on a sensitive immuno detection method which developed by gold nanoparticles coupled with alkaline phosphatase conjugated secondary antibody in turn recognized primary anti-serum raised against WSSV. We successfully enhanced the sensitivity of immuno-dot blot assay by 80 fold over the conventional method and visually it can be detected up to 1 ng/mL of purified WSSV. The approach described in this study is a prototype for the development of simple and inexpensive diagnostic tool will provide the routine screening of WSS in shrimp farms.

Paper based point-of-care testing disc for multiplex whole cell bacteria analysis

Point-of-care testing (POCT) of infectious bacterial agents offers substantial benefits for disease diagnosis, mainly by shortening the time required to obtain results and by making the test available bedside or at remote care centers. Immunochromatographic lateral flow biosensors offer a low cost, highly sensitive platform for POCT. In this article, we describe the fabrication and testing of a multiplex immuno-disc sensor for the specific detection of Pseudomonas aeruginosa and Staphylococcus aureus. Antibody conjugated gold nanoparticles were used as the signaling agents. The detection range of the bacteria lies within 500–5000 CFU/ml. The advantage of the immuno-disc sensor is that it does not require any preprocessing of biological sample and is capable of whole cell bacterial detection. We also describe the design and fabrication of a compact portable device which converts the color intensity of the gold nanoparticles that accumulate at the test region into a quantitative voltage reading proportional to the bacterial concentration in the sample. The combination of the immuno-disc and the portable color reader provides a rapid, sensitive, low cost, and quantitative tool for the detection of a panel of infectious agents present in the patient sample.

Surface Enhanced Raman Scattering of Neurotransmitter Release in Neuronal Cells Using Antibody Conjugated Gold Nanoparticles

This study demonstrated the potential feasibility of using antibody-conjugated gold nanoparticles as highly sensitive and homogeneous sensing probes for biological monitoring of neurotransmitters in neuronal cells. Bands at 1152 and 1322 cm(-1) were also similar to SERS of metal catecholates, and could be assigned to catechol ring vibration and carbon-oxygen stretches.

Targeted Cancer Treatment Using Anti-EGFR and -TFR Antibody-Conjugated Gold Nanoparticles Stimulated by Nonthermal Air Plasma

Targeted Cancer Treatment Using Anti-EGFR and -TFR Antibody-Conjugated Gold Nanoparticles Stimulated by Nonthermal Air Plasma

Targeted Cancer Treatment Using Anti-EGFR and -TFR Antibody-Conjugated Gold Nanoparticles Stimulated by Nonthermal Air Plasma

Targeted Cancer Treatment Using Anti-EGFR and -TFR Antibody-Conjugated Gold Nanoparticles Stimulated by Nonthermal Air Plasma

Specific Protein Detection Using Thermally Reduced Graphene Oxide Sheet Decorated with Gold Nanoparticle‐Antibody Conjugates

A highly sensitive and selective field-effect transistor biosensor using thermally reduced graphene oxide (TRGO) sheet decorated with gold nanoparticle-antibody conjugates is demonstrated. Probe antibody (anti-Immunoglobulin G) is labeled on the surface of the TRGO sheet through gold nanoparticles and electrical detection of the protein binding (Immunoglobulin G and anti-Immunoglobulin G) is accomplished by FET and dc measurements.

Pancreatic carcinoma cells are susceptible to noninvasive radio frequency fields after treatment with targeted gold nanoparticles

Gold and carbon nanoparticles absorb nonionizing radio frequency (RF) energy and release heat. Solid gold nanoparticles are delivered to cancer cells via conjugation with targeting antibodies. Here, 20-nm gold particles were conjugated to cetuximab, which is an epidermal growth factor receptor-1 (EGFR-1) antibody. A pancreatic carcinoma cell line that highly expresses EGFR-1, Panc-1, and Cama-1, which is a breast carcinoma cell line that minimally expresses EGFR-1, were treated with 100-nmol/L cetuximab-conjugated gold nanoparticles for 3 h (n = 4). Thirty-six hours later, the dishes were placed in an RF field with a generator power of 200 W for 5 min. After another 36 h, cell injury and death were evaluated with flow cytometry. The targeted cell line Panc-1 had a viability of 46% +/- 12%, whereas the Cama-1 cell had a viability of 92% +/- 2% after RF field exposure (P < .008). Transmission electron microscopy showed gold nanoparticle uptake in Panc-1 cells but negligible uptake by Cama-1 cells. Nontargeted cells do not internalize a sufficient amount of antibody-conjugated gold nanoparticles to induce injury in a noninvasive RF field. This technique could be useful in cancer treatment if a cancer-specific antibody is used to localize gold nanoparticles to malignant cells.

Anti-CD4-targeted Gold Nanoparticles Induce Specific Contrast Enhancement of Peripheral Lymph Nodes in X-ray Computed Tomography of Live Mice

Antibody-conjugated gold nanoparticles have been applied as a biologically targeted contrast agent in live mice for one of the most widely used medical imaging methods, X-ray computed tomography. Such nanoprobes directed toward the CD4 receptor lead to distinctly enhanced X-ray contrast of peripheral lymph nodes. This study demonstrates the general feasibility of biologically specific X-ray imaging in living animals and discusses basic requirements for the use of nanoparticles as a targeted X-ray contrast agent.

Organic electrochemical transistor based immunosensor for prostate specific antigen (PSA) detection using gold nanoparticles for signal amplification

We demonstrated a highly sensitive organic electrochemical transistor (OECT) based immunosensor with a low detection limit for prostate specific antigen/α1-antichymotrypsin (PSA–ACT) complex. The poly(styrenesulfonate) doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) based OECT with secondary antibody conjugated gold nanoparticles (AuNPs) provided a detection limit of the PSA–ACT complex as low as 1 pg/ml, as well as improved sensitivity and a dynamic range, due to the role of AuNPs in the signal amplification. The sensor performances were particularly improved in the lower concentration range where the detection is clinically important for the preoperative diagnosis and screening of prostate cancer. This result shows that the OECT-based immunosensor can be used as a transducer platform acceptable to the point-of-care (POC) diagnostic systems and demonstrates adaptability of organic electronics to clinical applications.