Facile preparation of small-sized gold nanoparticle decorated silica nanocomposites and their morphological changes in catalytic reactions.

Due to the unique physicochemical properties of gold nanoparticles (AuNPs) decorated silica nanostructures (SiO2@AuNPs), they show great potential for applications in catalysis, biosensing, optical devices and medicine. It is essential to explore the catalytic effect of SiO2@AuNPs and the understanding of the essential process of catalytic reactions. We have prepared SiO2@AuNPs by loading small-sized AuNPs on surface-modified silica nanospheres. SiO2@AuNPs was used as a catalyst for the catalytic reduction of 4-nitrophenol (4-NP) in the presence of excess NaBH4, and the results showed that with the increase of the amount of catalyst from 30 to 100µl, the corresponding rate constantKappwas increased from 6.44 × 10-3to 1.45 × 10-2s-1, and its TOF was as high as 1.326 × 103h-1, and the catalytic rate could still be maintained at 87% after five cycles. By analyzing the morphology and size of the SiO2supported AuNPs before and after the catalytic reaction, it can be seen that the atoms on the surface of small-sized AuNPs supported by silica have migrated during the catalytic process, which subsequently affects the catalytic efficiency of the structure. This study proves the good catalytic effect of SiO2@AuNPs structure and lays the foundation for its wider application.

A nanogold sensor test for tire wear chemicals based on the plasmon ruler approach.

The release of tire wear substances in the environment is raising concerns about potential impacts on aquatic ecosystems. The purpose of this study was to develop a quick and inexpensive screening test for the following tire wear substances: 6-phenylphenyldiamine quinone (6-PPD quinone), hexamethoxymethylmelamine (HMMM), 1-3-diphenylguanidine (1,3-DPG), and melamine. A dual strategy consisting of nanogold (nAu) signal intensity and the plasmonic ruler principle was used based on the spectral shift from the unaggregated free-form nAu from 525 nm to aggregated nAu at higher wavelengths. The shift in resonance corresponded to the relative sizes of the tire wear substances at the surface of nAu: 6-PPD (560 nm), HMMM (590 nm), 1,3-DPG (620 nm), and melamine (660 nm) in a concentration-dependent manner. When present in mixtures, a large indiscriminate band between 550 and 660 nm with a maximum corresponding to the mean intermolecular distance of 0.43 nm from the tested individual substances suggests that all compounds indiscriminately interacted at the surface of nAu. An internal calibration methodology was developed for mixtures and biological extracts from mussels and biofilms and revealed a proportional increase in absorbance at the corresponding resonance line for each test compound. Application of this simple and quick methodology revealed the increased presence of melamine and HMMM compounds in mussels and biofilms collected at urban sites (downstream city, road runoffs), respectively. The data also showed that treated municipal effluent decreased somewhat melamine levels in mussels.

Tailoring plasmonic sensing strategies for the rapid and sensitive detection of hypochlorite in swimming water samples.

A tunable plasmonic sensor has been developed by varying the dextran content in the initially synthesized dextran-gold nanoparticle (dAuNPs) solution. A colloidal nanogold solution (dAuNPs-Sol) was initially prepared using dextran and gold salt in alkaline media by a one-pot green synthetic route. The dAuNPs-Sol was combined with varying amounts of dextran (ranging from 0.01 to 30.01%) to create a tunable probe, along with different solid formats, including tablet (dAuNPs-Tab), powder (dAuNPs-Powder), and composite (dAuNPs-Comp). Both the liquid and solid phase plasmonic probes were characterized using UV-vis spectroscopy, transmission electron microscopy (TEM) dynamic light scattering (DLS), and zeta potential analysis. The impact of dextran content in the dAuNP solution is studied in terms of surface charge and hydrodynamic size. The influence of operational treatments used to achieve solid dAuNPs probes is also explored. All plasmonic probes were employed to detect a broad range of OCl¯ concentrations (ranging from µM to mM) in water through aggregation followed by calculating a lower and upper limit of detection (LLoD, ULoD) of the proposed colorimetric sensors. Results indicate that the most sensitive detection is achieved with a lower dextran content (0.01%), which exhibits an LLoD of 50 µM. The dAuNPs-Sol sensor is selective and demonstrates real-world applicability, as confirmed by interference analysis and successful testing with various water samples. Additionally, it is found that a 20 × concentration of dextran-coated gold nanoparticles could be attained without any changes in the particle morphology. This concentration is achieved through a straightforward process that does not require the use of a centrifuge machine. This finding highlights the practicality and simplicity of the method, indicating its potential for scalable and cost-effective production of concentrated dAuNPs without compromising their structural integrity.

The applications of epigallocatechin gallate (EGCG)-nanogold conjugate in cancer therapy.

Cancer has recently increased the death toll worldwide owing to inadequate therapy and decreased drug bioavailability. Long-term and untargeted chemotherapeutic exposure causes toxicity to healthy cells and drug resistance. These challenges necessitate the development of new methods to increase drug efficacy. Nanotechnology is an emerging field in the engineering of new drug delivery platforms. The phytochemical epigallocatechin gallate (EGCG), the main component of green tea extract and its most bioactive component, offers novel approaches to cancer cell eradication. The current review focuses on the nanogold-based carriers containing EGCG, with an emphasis on the chemotherapeutic effects of EGCG in cancer treatment. The nanoscale vehicle may improve the EGCG solubility and bioavailability while overcoming constraints and cellular barriers. This article reviewed the phytochemical EGCG-based gold nanoplatforms and their major anticancer applications, both individually, and in combination therapy in a few cases.

Bacterial DNA Recognition by SERS Active Plasma-Coupled Nanogold.

It is shown that surface-enhanced Raman spectroscopy (SERS) can identify bacteria based on their genomic DNA composition, acting as a "sample-distinguishing marker". Successful spectral differentiation of bacterial species was accomplished with nanogold aggregates synthesized through single-step plasma reduction of the ionic gold-containing vapored precursor. A high enhancement factor (EF = 107) in truncated coupled plasmonic particulates allowed SERS-probing at nanogram sample quantities. Simulations confirmed the occurrence of the strongest electric field confinement within nanometric gaps between gold dimers/chains from where the molecular fingerprints of bacterial DNA fragments gained photon scattering enhancement. The most prominent Raman modes linked to fundamental base-pair molecular vibrations were deconvoluted and used to proceed with nitrogenous base content estimation. The genomic composition (percentage of guanine-cytosine and adenine-thymine) was successfully validated by third-generation sequencing using nanopore technology, further proving that the SERS technique can be employed to swiftly specify bioentities by the discriminative principal-component statistical approach.

The Preparation of Silver and Gold Nanoparticles in Hyaluronic Acid and the Influence of Low-Pressure Plasma Treatment on Their Physicochemical and Microbiological Properties.

Nanometals constitute a rapidly growing area of research within nanotechnology. Nanosilver and nanogold exhibit significant antimicrobial, antifungal, antiviral, anti-inflammatory, anti-angiogenic, and anticancer properties. The size and shape of nanoparticles are critical for determining their antimicrobial activity. In this study, silver and gold nanoparticles were synthesized within a hyaluronic acid matrix utilizing distilled water and distilled water treated with low-pressure, low-temperature glow plasma in an environment of air and argon. Electron microscopy, UV-Vis and FTIR spectra, water, and mechanical measurements were conducted to investigate the properties of nanometallic composites. This study also examined their microbiological properties. This study demonstrated that the properties of the composites differed depending on the preparation conditions, encompassing physicochemical and microbiological properties. The application of plasma-treated water under both air and argon had a significant effect on the size and distribution of nanometals. Silver nanoparticles were obtained between the range of 5 to 25 nm, while gold nanoparticles varied between 10 to 35 nm. The results indicate that the conditions under which silver and gold nanoparticles are produced have a significant effect on their mechanical and antibacterial properties.

Next-generation engineered nanogold for multimodal cancer therapy and imaging: a clinical perspectives.

Cancer is one of the significant threats to human life. Although various latest technologies are currently available to treat cancer, it still accounts for millions of death each year worldwide. Thus, creating a need for more developed and novel technologies to combat this deadly condition. Nanoparticles-based cancer therapeutics have offered a promising approach to treat cancer effectively while minimizing adverse events. Among various nanoparticles, nanogold (AuNPs) are biocompatible and have proved their efficiency in treating cancer because they can reach tumors via enhanced permeability and retention effect. The size and shape of the AuNPs are responsible for their diverse therapeutic behavior. Thus, to modulate their therapeutic values, the AuNPs can be synthesized in various shapes, such as spheres, cages, flowers, shells, prisms, rods, clusters, etc. Also, attaching AuNPs with single or multiple targeting agents can facilitate the active targeting of AuNPs to the tumor tissue. The AuNPs have been much explored for photothermal therapy (PTT) to treat cancer. In addition to PTT, AuNPs-based nanoplatforms have been investigated for combinational multimodal therapies in the last few years, including photodynamic therapy, chemotherapy, radiotherapy, immunotherapy, etc., to ablate cancer cells. Thus, the present review focuses on the recent advancements in the functionalization of AuNPs-based nanoconstructs for cancer imaging and therapy using combinatorial multimodal approaches to treat various cancers.

2D disposable stochastic sensors for molecular recognition and quantification of maspin in biological samples.

Three disposable stochastic sensors using nanolayer deposition of a graphene nanocomposite comprising graphene nanoparticles and gold nanoparticles, on different supports: silk, plastic, and paper, and modified with chitosan, were characterized and validated for molecular recognition and quantification of maspin in biological samples. Very low limits of determination (of pg mL-1 magnitude order) were recorded (5.12 pg mL-1 for the sensor based on silk at pH 7.40 and on copy paper at pHs 3.00 and 7.40; 16 ng mL-1 at pH 7.40 for the sensor based on plastic, 41.00 pg mL-1 for the sensor based on silk at pH 3.00, and 204.00 pg mL-1 for the sensor based on plastic, at pH 3.00), with wide linear concentration ranges (5.12 × 10-12-2.00 × 10-6 g mL-1 for the sensors based on silk at pH 7.40, and on copy paper at pH 3.00; 5.12 × 10-12-8.00 × 10-7 g mL-1 for the sensor based on copy paper at pH 7.40; 1.60 × 10-8-2.00 × 10-6 g mL-1 for the sensor based on plastic at pH 7.40; 4.10 × 10-14-2.00 × 10-6 g mL-1 for the sensor based on silk, at pH 3.00; and 2.04 × 10-13-8.00 × 10-7 g mL-1 for the sensor based on plastic at pH 3.00) allowing the molecular recognition and quantification of maspin in healthy people and patients with gastric cancer, when a potential of 125 mV vs. Ag/AgCl was applied. The recoveries of maspin in whole blood, saliva, urine, and tissue samples were higher than 95.00%, with a relative standard deviation lower than 1.0%.

Nano-gold-enhanced LAMP method for qualitative visual detection of Salmonella in milk.

Since Salmonella can cause foodborne disease and public health safety issues and requires a robust, rapid, on-site detection method, a novel visual qualitative method with nano-gold-enhanced loop-mediated isothermal amplification (LAMP) reaction was established for detecting Salmonella in an integrated tube. During the experiment, nano-gold were used to enhance LAMP amplification, improving amplification efficiency and shortening the reaction time to within 30 min. Visual qualitative detection is achieved via negative staining, involving the addition of CuSO4 to the final products of the LAMP reaction. Ring-like white accumulation occurs in the absence of Salmonella targets but not when they are present. After completing the LAMP reaction, the integration tube was shaken gently for 1 min to observe the liquid phase system changes, realizing the closed tube detection of Salmonella. The process resolved the challenge presented by cross-contamination, false positives, and nonspecific amplification during the LAMP reaction. This method was used to detect Salmonella in milk, further highlighting its prospects in the field of rapid food safety detection.

Pharmacological Role of Functionalized Gold Nanoparticles in Disease Applications.

Gold has always been regarded as a symbol of nobility, and its shiny golden appearance has always attracted the attention of many people. Gold has good ductility, molecular recognition properties, and good biocompatibility. At present, gold is being used in many fields. When gold particles are as small as several nanometers, their physical and chemical properties vary with their size in nanometers. The surface area of a nano-sized gold surface has a special effect. Therefore, gold nanoparticles can, directly and indirectly, give rise to different biological activities. For example, if the surface of the gold is sulfided. Various substances have a strong chemical reactivity and are easy to combine with sulfhydryl groups; hence, nanogold is often used in biomedical testing, disease diagnosis, and gene detection. Nanogold is easy to bind to proteins, such as antibodies, enzymes, or cytokines. In fact, scientists use nanogold to bind special antibodies, as a tool for targeting cancer cells. Gold nanoparticles are also directly cytotoxic to cancer cells. For diseases caused by inflammation and oxidative damage, gold nanoparticles also have antioxidant and anti-inflammatory effects. Based on these unique properties, gold nanoparticles have become the most widely studied metal nanomaterials. Many recent studies have further demonstrated that gold nanoparticles are beneficial for humans, due to their functional pharmacological properties in a variety of diseases. The content of this review will be the application of gold nanoparticles in treating or diagnosing pressing diseases, such as cancers, retinopathy, neurological diseases, skin disorders, bowel diseases, bone cartilage disorders, cardiovascular diseases, infections, and metabolic syndrome. Gold nanoparticles have shown very obvious therapeutic and application potential.

Combination of infra-red light with nanogold targeting macrophages in the treatment of Leishmania major infected BALB/C mice.

PURPOSE: In the treatment of cutaneous leishmaniasis (CL), developing drug resistance, existing toxic effects of drugs and failure respond to treatment cause the need to try different treatment methods. We investigated the effect of gold-conjugated macrophage-specific antibody on amastigotes under infra-red light for the treatment of CL. METHODS: Female BALB/c (4-8 weeks old, 20 ± 5 g weight) mice were used in the study. The L. major strain was inoculated on the soles of mice in amastigote form and subpassed. Nanogold (Au), Au + macrophage-specific antibody (MSA) modification and near infra-red (NIR) (5 seconds) were applied to mice groups that developed cutaneous leishmaniasis on their soles. On the 5th and 10th days of the treatment, the lesions were examined clinically and pathologically. RESULTS: When the erythema values were examined, the highest decrease was calculated in the Au + MSA + NIR group in the measurements made on the 10th day (p < 0.014). The best improvement in 10th day measurements is in the NIR and Au + MSA + NIR groups when area values were examined (p = 0.011, p = 0.001). There was a statistically significant difference between the groups in terms of parasite load (PL) (p < 0.005) in pathological evaluation. According to PL grouping, the best result is NIR (p = 0.002). When both main titles (clinical and pathological) are examined, the Au + MSA + NIR group is thought to have an optimal therapeutical feature. CONCLUSIONS: Au + MSA + NIR combination could be a new treatment approach for CL treatment.

Endocytosed nanogold fiducials for improved in-situ cryo-electron tomography tilt-series alignment.

Cryo-electron tomography (CET) on cryo-focused ion beam (FIB)-milled lamellae is becoming a powerful technique for determining the structure of macromolecular complexes in their native cellular environment. Prior to tomogram reconstruction, CET tilt-series recorded on FIB lamellae need to be aligned. Traditionally, CET tilt-series alignment is performed with 5-20 nm gold fiducials, but it has thus far proven difficult to apply this to FIB lamellae of eukaryotic cells. In here, we describe a simple method to allow uptake of bovine serum albumin (BSA)-gold fiducials into mammalian cells via endocytosis, which can subsequently be used as fiducials for tilt-series alignment of cryo-FIB lamellae. We compare the alignment of tilt-series with BSA-gold fiducials to fiducial-less patch-tracking, and find better alignment results with BSA-gold. This technique can contribute to understand cells at a structural and ultrastructural level with both cryo- and room-temperature electron tomography. Furthermore, fluorescently labeled BSA-gold has the potential to be used as fiducials for correlative light and electron microscopy studies.

Catalytic effects of magnetic and conductive nanoparticles on immobilized glucose oxidase in skin sensors.

Wearable skin sensors is a promising technology for real-time health care monitoring. They are of particular interest for monitoring glucose in diabetic patients. The concentration of glucose in sweat can be more than two orders of magnitude lower than in blood. In consequence, the scientific and technological efforts are focused in developing new concepts to enhance the sensitivity, decrease the limit of detection (LOD) and reduce the response time (RT) of glucose skin sensors. This work explores the effect of adsorbed superparamagnetic magnetite nanoparticles (MNPs) and conductive nanoparticles (CNPs) on carbon nanotube substrates (CNTs) used to immobilize glucose oxidase enzyme in the working electrode of skin sensors. MNPs and CNPs are made of magnetite and gold, respectively. The performance of the sensors was tested in standard buffer solution, artificial sweat, fresh sweat and on the skin of a healthy volunteer during an exercise session. In the case of artificial sweat, the presence of MNPs accelerated the RT from 7 to 5 s at the expense of increasing the LOD from 0.017 to 0.022 mM with slight increase of the sensitivity from 4.90 to 5.09µAm M-1cm-2. The presence of CNPs greatly accelerated the RT from 7 to 2 s and lowered the LOD from 0.017 to 0.014 mM at the expense of a great diminution of the sensitivity from 4.90 to 4.09µAm M-1cm-2. These effects were explained mechanistically by analyzing the changes in the concentration of free oxygen and electrons promoted by MNPs and CNPs in the CNTs and its consequences on the the glucose oxidation process.

Nanogold Particles Suppresses 5-Flurouracil-Induced Renal Injury: An Insight into the Modulation of Nrf-2 and Its Downstream Targets, HO-1 and γ-GCS.

The development of the field of nanotechnology has revolutionized various aspects in the fields of modern sciences. Nano-medicine is one of the primary fields for the application of nanotechnology techniques. The current study sheds light on the reno-protective impacts of gold nano-particles; nanogold (AuNPs) against 5-flurouracil (5-FU)-induced renal toxicity. Indeed, the use of 5-FU has been associated with kidney injury which greatly curbs its therapeutic application. In the current study, 5-FU injection was associated with a significant escalation in the indices of renal injury, i.e., creatinine and urea. Alongside this, histopathological and ultra-histopathological changes confirmed the onset of renal injury. Both gene and/or protein expression of nuclear factor erythroid 2-related factor 2 (Nrf-2) and downstream antioxidant enzymes revealed consistent paralleled anomalies. AuNPs administration induced a significant renal protection on functional, biochemical, and structural levels. Renal expression of the major sensor of the cellular oxidative status Nrf-2 escalated with a paralleled reduction in the renal expression of the other contributor to this axis, known as Kelch-like ECH-associated protein 1 (Keap-1). On the level of the effector downstream targets, heme oxygenase 1 (HO-1) and gamma-glutamylcysteine synthetase (γ-GCS) AuNPs significantly restored their gene and protein expression. Additionally, combination of AuNPs with 5-FU showed better cytotoxic effect on MCF-7 cells compared to monotreatments. Thus, it can be inferred that AuNPs conferred reno-protective impact against 5-FU with an evident modulatory impact on Nrf-2/Keap-1 and its downstream effectors, HO-1 and γ-GCS, suggesting its potential use in 5-FU regimens to improve its therapeutic outcomes and minimize its underlying nephrotoxicity.

Paper-Based Analytical Devices for the Rapid and Direct Electrochemical Detection of Hydrogen Peroxide in Tomato Leaves Inoculated with Botrytis cinerea.

Hydrogen peroxide (H2O2) is an important signaling molecule and plays key roles in multiple plant physiological processes. The rapid and direct monitoring of H2O2 could improve our understanding of its regulatory mechanisms in plants. In this study, we developed a paper-based analytical device consisting of a disposable nano-gold modified indium tin oxide working electrode to provide a platform for the rapid and direct detection of H2O2. The total analytical time was dramatically shortened to be approximate 3 min due to the avoidance of the time-consuming and complex treatment of plant samples. In addition, the amount of plant samples required was less than 3 mg in our approach. We used this system to monitor the concentrations of H2O2 in tomato leaves infected by Botrytiscinerea within 24 h. Our results showed that the concentration of H2O2 in tomato leaves was increased in the initial phase, peaked at 1.5 µmol gFW-1 at 6 h, and then decreased. The production trend of H2O2 in tomato leaves inoculated with Botrytiscinerea detected with our approach is similar to the 3,3-diaminobenzidine staining method. Taken together, our study offers a rapid and direct approach for the detection of H2O2, which will not only pave the way for the further investigation of the regulation mechanisms of H2O2 in plants, but also promote the development of precision agriculture technology.

Microbial contamination and plaque scores of nanogold-coated toothbrush.

OBJECTIVE: The study aimed to evaluate the microbial contamination and plaque scores of nanogold-coated and uncoated toothbrushes. METHODS: This study was designed as a single-centre, parallel, examiner-blinded, randomized, two-group clinical trial. Eighty-four participants were enrolled and randomly assigned to receive either a nanogold or uncoated toothbrush. Basic periodontal therapy was performed for all the recruited subjects, and plaque scores of zero were considered baseline values. All participants were instructed to follow a twice-daily brushing regimen without dentifrice and to refrain from other oral hygiene care during the one-week study period. Plaque levels were assessed after one week using the Turesky modification of the Quigley-Hein Plaque Index (TMQHPI). The bristles were tested for microbial contamination by viable cell counting. The recorded data were statistically analysed, and a P-value of <.05 was accepted as statistically significant. RESULTS: After one week of brushing without using toothpaste, the mean plaque index scores were 0.37 ± 0.07 in the nanogold group and 0.58 ± 0.10 in the uncoated group. A significant difference in the mean plaque scores was observed between the groups (P < .001). The mean colony-forming unit (CFU) was 21 ± 48.8 for the nanogold-coated group and 100 ± 128.4 for the uncoated group. The difference in the mean CFUs observed between the groups was significant (P = .014). CONCLUSION: The use of a nanogold-coated toothbrush demonstrated significantly lower bristle contamination and lower plaque scores after one week compared with uncoated toothbrushes without using dentifrice.

Mitochondrial accumulation of amyloid ß (Aß) peptides requires TOMM22 as a main Aß receptor in yeast.

Mitochondrial accumulation of intracellular ß-amyloid (Aß) peptides is present in the brains of individuals with Alzheimer's disease (AD) as well as in related mouse models of AD. This accumulation is extremely toxic because Aß disrupts the normal functions of many mitochondrial proteins, resulting in significant mitochondrial dysfunction. Therefore, understanding the mitochondrial accumulation of Aß is useful for future pharmaceutical design of drugs to address mitochondrial dysfunction in AD. However, the detailed molecular mechanism of this accumulation process remains elusive. Here, using yeast mitochondria, we present direct experimental evidence suggesting that Aß is specifically recognized by translocase of outer mitochondrial membrane subunit 22 (Tom22 in yeast; TOMM22 in human), a noncanonical receptor within the mitochondrial protein import machinery, and that this recognition is critical for Aß accumulation in mitochondria. Furthermore, we found that residues 25-42 in the Aß peptide mediate the specific interaction with TOMM22. On the basis of our findings, we propose that cytosolic Aß is recognized by TOMM22; transferred to another translocase subunit, TOMM40; and transported through the TOMM channel into the mitochondria. Our results not only confirm that yeast mitochondria can be used as a model to study mitochondrial dysfunction caused by Aß peptides in AD but also pave the way for future studies of the molecular mechanism of mitochondrial Aß accumulation.

Xyloglucan in the primary cell wall: assessment by FESEM, selective enzyme digestions and nanogold affinity tags.

Xyloglucan has been hypothesized to bind extensively to cellulose microfibril surfaces and to tether microfibrils into a load-bearing network, thereby playing a central role in wall mechanics and growth, but this view is challenged by newer results. Here we combined high-resolution imaging by field emission scanning electron microscopy (FESEM) with nanogold affinity tags and selective endoglucanase treatments to assess the spatial location and conformation of xyloglucan in onion cell walls. FESEM imaging of xyloglucanase-digested cell walls revealed an altered microfibril organization but did not yield clear evidence of xyloglucan conformations. Backscattered electron detection provided excellent detection of nanogold affinity tags in the context of wall fibrillar organization. Labelling with xyloglucan-specific CBM76 conjugated with nanogold showed that xyloglucans were associated with fibril surfaces in both extended and coiled conformations, but tethered configurations were not observed. Labelling with nanogold-conjugated CBM3, which binds the hydrophobic surface of crystalline cellulose, was infrequent until the wall was predigested with xyloglucanase, whereupon microfibril labelling was extensive. When tamarind xyloglucan was allowed to bind to xyloglucan-depleted onion walls, CBM76 labelling gave positive evidence for xyloglucans in both extended and coiled conformations, yet xyloglucan chains were not directly visible by FESEM. These results indicate that an appreciable, but still small, surface of cellulose microfibrils in the onion wall is tightly bound with extended xyloglucan chains and that some of the xyloglucan has a coiled conformation.

Development of an immunochromatographic assay for the specific detection of Bacillus thuringiensis (Bt) Cry1Ab toxin.

Cry1Ab has been widely used in genetically modified (GM) crops and its amino acid sequence had high identity to Cry1Ac toxin. Existing nanogold immunochromatographic strips cannot distinguish Cry1Ab from Cry1Ac toxin. In this study, a rapid (5-6 min), qualitative nanogold immunochromatographic strip was successfully developed for the specific detection of Cry1Ab toxin. The assay was based on double antibody sandwich format with the visual detection limit (vLOD) of 0.1 µg mL-1. The results of immunochromatographic assay were all positive validated against the DAS-ELISA (recoveries between 109.6 and 111.8%). In addition, 10%, 5% and 0% error probability results were found in 20 times repeated tests for Cry1Ab concentration of 0.1, 0.2, 0.5 and 1 µg mL-1, respectively, demonstrating the reproducibility of the test strip. Furthermore, the test strip could be stored for 3 months under dry conditions without significant loss of sensitivity. Furthermore, the practical sample analysis results showed that the test strip was able to detect the presence of Cry1Ab in GM materials containing as low as 0.5% MON 810 Bt maize which indicated the practical value of the test strip. To our knowledge, this is the first report on the detection of Cry1Ab by immunochromatographic assay without interference from Cry1Ac toxin.

Gold Nanoparticles in Cancer Treatment.

Colloidal gold has been studied for its potential application in medicine for centuries. However, synthesis and evaluation of various gold nanoparticles have only recently been met with a wide interest of scientists. Current studies confirm numerous advantages of nanogold over different nanomaterials, primarily due to highly optimized protocols for the production of gold nanoparticles of countless sizes and shapes, featured with unique properties. The possibility to modify the surface of nanogold particles with different targeting and functional compounds significantly broadens the range of their potential biomedical applications, with particular emphasis on cancer treatment. Functionalized gold nanoparticles exhibit good biocompatibility and controllable biodistribution patterns, which make them particularly fine candidates for the basis of innovative therapies. Considering the high amount of scientific data on nanogold, this review summarizes recent advances in the field of medical application of gold nanoparticles for the therapy of cancer.