Systematic Evaluation of Protein-Based Nanoparticles for Stable Delivery of Small Interfering RNA

Developing a delivery vehicle to protect siRNA from degradation is a significant challenge. To solve this challenge, researchers attempted to use protein-based nanoparticles to deliver siRNA with limited to moderate success. However, a systematic investigation of comparing the ability of different protein-based nanoparticles as vehicles to deliver siRNA stably within cells is still unavailable. Therefore, in this study we synthesized a library of both non-targeted (proteinsiRNA) nanoparticles (NPs) and targeted (antibody conjugated protein-siRNA) NPs and evaluated ability to stably deliver siRNA in to cells to silence the gene of interest. We investigated nanoparticles of casein, bovine serum albumin, and gelatin for the delivery of siRNA. We synthesized and characterized a total of 12 nanoconjugates; in these conjugates, we either encapsulated, electrostatically attached, or covalently conjugated siRNA. We evaluated the efficiency of attaching siRNA to nanoconjugates, stability, and cellular delivery. The ability of siRNA to silence the protein of interest in cancer cells was also investigated. Among non-targeted conjugates, BSA matrix imparted relatively high stability to siRNA when encapsulated. Among targeted nanoconjugates, gelatin nanoparticles rendered high stability to siRNA upon covalent conjugation to the surface. On comparing with both targeted and non-targeted NPs for release of siRNA within cells, antibody-gelatin-siRNA conjugate exhibited high release and functional activity (down-regulation of target protein levels) within the cells as confirmed by both fluorescence imaging and Western blotting. In summary, our investigations show that targeted gelatin nanoparticles and non-targeted BSA nanoparticles possess high stability and excellent gene suppression capabilities and warrants further studies. We can extend the results from this study to develop stable siRNA delivery vehicles to specifically silence the protein of interest.

Silencing AXL by covalent siRNA-gelatin-antibody nanoconjugate inactivates mTOR/EMT pathway and stimulates p53 for TKI sensitization in NSCLC

Non-small cell lung cancer (NSCLC) is the leading cause of cancer mortality with the 5-year survival rate at a dismal 16% for the past 40 years. Drug resistance is a major obstacle to achieving long-term patient survival. Identifying and validating molecular biomarkers responsible for resistance and thereby adopting multi-directional therapy is necessary to improve the survival rate. Previous studies indicated ~20% of tyrosine kinase inhibitor (TKI) resistant NSCLC patients overexpress AXL with increase in EMT and decrease in p53 expression. To overcome the resistance, we designed gelatin nanoparticles covalently conjugated with EGFR targeting antibody and siRNA (GAbsiAXL). GAbsiAXL efficiently silences AXL, decreases mTOR and EMT signaling with concomitant increase in p53 expression. Because of the molecular changes, the AXL silencing sensitizes the cells to TKI. Our results show AXL overexpression has an important role in driving TKI resistance through close association with energy-dependent mitochondrial pathways.

Targeting HMGA protein inhibits retinoblastoma cell proliferation

We describe a novel synthetic strategy for conjugating HMGA2 siRNA and the HMGA aptamer to the nucleolin aptamer and nucleolin antibody, respectively. Our studies demonstrate that these conjugates inhibit cell proliferation in retinoblastoma cells.

A novel approach to target HMGA proteins in retinoblastoma using HMGA2 siRNA–nucleolin aptamer and HMGA aptamer–nucleolin antibody conjugates was developed.

Abstract 4171: Combined AXL/FN14 inhibition sensitize drug-resistant NSCLC in vitro and in vivo

Lung cancer is the number one cause of cancer-related deaths in both men and women with a median survival time of 8-10 months’ post treatment. Non Small Cell Lung Cancer (NSCLC) accounts for 80% of the lung cancers and the treatment plan is determined based on the active mutations (EGFR, ALK/ROS, and KRAS) present in the tumor. Patients bearing EGFR mutation initially respond to targeted tyrosine kinase inhibitor (TKI) therapy and after 10-14 months of treatment acquire TKI resistance. Consequently, the median PFS for NSCLC patients with EGFR mutation is only 9.5 months. The reason for this acquired drug resistance is not yet fully understood. Recent studies have reported oncogenes such as AXL could be responsible for TKI resistance. Therefore, understanding the mechanism of drug resistance is key in developing a solution to overcome the problem. For this study, we first examined the resistance mechanism and developed a biodegradable targeted nanoparticle based solution to systematically investigate the role of AXL in resistant NSCLC cell lines. In this study we (1) downregulated AXL using siRNA and separately (2) knocked out the AXL gene using crRNA (CRISPR) and treated with TKI. Our results show that AXL is responsible for activation of several EMT related proteins and upregulation of mTOR pathway. We believe the upregulation of these proteins is essential for cancer cells to switch pathways for proliferation and regulating miRNAs linked to mutations. Our results further confirm that AXL is responsible for regulating MMP-2 that is associated with cell invasion. Based on data from multiple cell lines such as H820 and A549, we demonstrate that AXL upregulation is responsible for resistance independent of EGFR activating mutations. The elucidated pathway for drug resistance was further confirmed in cell lines generated by knocking-out the AXL gene. Interpretation for AXL signaling and drug resensitization was confirmed by Western blotting, Zymography, Invasion & Migration assay, Apoptosis assay and MTT toxicity assay. We performed mRNA and miRNA analysis using qRT-PCR to understand gene expression post treatment. During the process of our investigation, we found that NSCLC cells undergo further survival cross talk with other biomarkers. Indeed, we report the first experimental evidence of a survival cross talk between AXL and FN14, a wound healing gene, that enhance cell survival post treatment. Down regulation of both AXL and FN14 dramatically reduced the IC50 of TKI. Based on the mechanism, we designed a gelatin nanoparticle that can carry both AXL and FN14 to deliver it in the tumor cell. The nanoparticle is targeted to tumor using EGFR-antibody and releases the silencing RNA within cytoplasm. We further demonstrated that dual-inhibition of AXL and FN14 in A549 mice xenografts showed tumor reduction compared to controls. In conclusion, inhibition of AXL and FN14 can maximize therapeutic response of TKI, wherein AXL is upregulated before or during drug treatment.

Citation Format: Dhananjay Suresh, Ajit Zambre, Soumavo Mukherjee, Shreya Ghoshdastidar, Jennifer L. Schnabel, Sarah Chapman, W. Matthew Leevy, Anandhi Upendran, Raghuraman Kannan. Combined AXL/FN14 inhibition sensitize drug-resistant NSCLC in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4171. doi:10.1158/1538-7445.AM2017-4171

In vitro/in vivo “peeling” of multilayered aminocarboxylate gold nanoparticles evidenced by a kinetically stable 99mTc-label

The BBN-Au-DTDTPA coating is selectively released upon interaction with glutathione (GSH), rendering this nanoplatform potentially useful for GSH-mediated drug delivery.

Targeted nanoconjugate co-delivering siRNA and tyrosine kinase inhibitor to KRAS mutant NSCLC dissociates GAB1-SHP2 post oncogene knockdown

A tri-block nanoparticle (TBN) comprising of an enzymatically cleavable porous gelatin nanocore encapsulated with gefitinib (tyrosine kinase inhibitor (TKI)) and surface functionalized with cetuximab-siRNA conjugate has been synthesized. Targeted delivery of siRNA to undruggable KRAS mutated non-small cell lung cancer cells would sensitize the cells to TKI drugs and offers an efficient therapy for treating cancer; however, efficient delivery of siRNA and releasing it in cytoplasm remains a major challenge. We have shown TBN can efficiently deliver siRNA to cytoplasm of KRAS mutant H23 Non-Small Cell Lung Cancer (NSCLC) cells for oncogene knockdown; subsequently, sensitizing it to TKI. In the absence of TKI, the nanoparticle showed minimal toxicity suggesting that the cells adapt a parallel GAB1 mediated survival pathway. In H23 cells, activated ERK results in phosphorylation of GAB1 on serine and threonine residues to form GAB1-p85 PI3K complex. In the absence of TKI, knocking down the oncogene dephosphorylated ERK, and negated the complex formation. This event led to tyrosine phosphorylation at Tyr627 domain of GAB1 that regulated EGFR signaling by recruiting SHP2. In the presence of TKI, GAB1-SHP2 dissociation occurs, leading to cell death. The outcome of this study provides a promising platform for treating NSCLC patients harboring KRAS mutation.

Abstract 1332: Dual antibody gold nanoconjugate significantly enhances cytotoxicity in metastatic breast cancer

Background: Metastatic breast cancer is the second leading cause of cancer-related deaths of women in the United States. First line treatment for Her2-positive metastatic breast cancer patient is combination therapy involving pertuzumab, trastuzumab, and docetaxel. Both pertuzumab and trastuzumab targets Her2, but works in complementary ways in increasing the cytotoxicity. Indeed, combination of these two antibody drugs for treatment has shown excellent survival benefits. We hypothesized that by covalently attaching these two antibodies to a single nanoparticle would accelerate the cancer cell death in lower concentrations of antibodies. In this study, we covalently conjugated trastuzumab and pertuzumab to gold nanoparticle (AuNP) and investigated the cytotoxicity in metastatic breast cancer cells.

Methods: Gold nanoparticles of core size 16 nm were prepared and modified using heterofunctional end terminal carboxylic polyethylene glycol (PEG) linker. The carboxyl terminals were activated by conventional EDC/NHS procedure followed by simultaneous addition of antibodies. The dual antibody gold nanoconjugates (AuNP-Dual Ab) was purified by HPLC using size exclusion column and characterized in detail by routine analytical techniques. Detailed proteomic analysis was performed on the dual antibody gold nanoconjugate. The binding affinity of AuNP-Dual Ab was investigated on HER2+ve SkBR3 cells using dark field microscopy. In vitro cytotoxicity evaluations of AuNP-Dual Ab were performed on HER2 expressing SKBR3 and BT474 cell lines. The effect of AuNP-Dual Ab on signal transduction and phosphorylation status mediated by HER family proteins were evaluated by monitoring the HER2, HER3, AKT, ERK, MEK protein expression through western blot analysis. In vivo studies have been performed in metastatic breast tumor mice models to evaluate the therapeutic efficacy of the nanoconjugate.

Results: AuNP-Dual Ab was isolated from the free antibodies by HPLC. We confirmed both the presence and the structural identity of antibodies covalently attached to AuNP using proteomics. TEM immunohistochemistry and dark field microscopy showed AuNP-Dual-Ab possess high receptor binding affinity with Her2+ve breast cancer cells. We investigated the cytotoxicity of AuNP-Dual-Ab in SKBR-3 and BT474 human breast cancer cells. Our studies reveal that AuNP-Dual-Ab is 60 fold higher cytotoxic than non-antibody coated AuNPs, antibodies, and combination antibodies. Western blot analysis showed down regulation of AkT and phospho-AkT proteins while expression of MEK and phospho-MEK proteins was un-altered. We believe the increase in cytotoxicity is possibly due to effective transport of antibodies to cancer cells.

Conclusions: The in vitro studies demonstrate that AuNP-Dual Ab is promising and can potentially overcome the problem of resistance. In vivo studies are ongoing on metastatic breast tumor mice models for therapy evaluation.

Citation Format: Ajit Zambre, Anandhi Upendran, Matthew Leevy, Sarah Chapman, Raghuraman Kannan. Dual antibody gold nanoconjugate significantly enhances cytotoxicity in metastatic breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1332.

Three-Dimensional Nanocomposites: Fluidics Driven Assembly of Metal Nanoparticles on Protein Nanostructures and Their Cell-Line-Dependent Intracellular Trafficking Pattern

Three-dimensional nanocomposites prepared using two different families of nanomaterials holds significant relevance pertaining to biological applications. However, integration of the two distinct nanomaterials with precision to control the overall compositional homogeneity of the resulting 3D nanocomposite is a synthetic challenge. Conventional reactions result in nanocomposites with heterogeneous composition and render useless. To address this challenge, we have developed a fluidics-mediated process for controlling the interaction of nanoparticles to yield a compositional uniform multidimensional nanoparticle; as an example, we demonstrated the integration of gold nanoparticles on gelatin nanoparticles. The composition of the nanocomposite is controlled by reacting predetermined number of gold nanoparticles to a known number of thiolated gelatin nanoparticles at any given time within a defined cross-sectional area. Using the fluidics process, we developed nanocomposites of different composition: [gelatin nanoparticles-(gold nanoparticles)x] where xaverage = 2, 12, or 25. The nanocomposites were further surface conjugated with organic molecules such as fluorescent dye or polyethylene glycol (PEG) molecules. To study the biological behavior of nanocomposite, we investigated the cellular internalization and trafficking characteristics of nanocomposites in two human cancer cell lines. The nanocomposites exhibited a three-stage cellular release mechanism that enables the translocation of gold nanoparticles within various cellular compartments. In summary, the three-dimensional nanocomposite serves as a novel platform for developing well-defined protein-metal nanocomposites for potential drug delivery, sensory, and molecular imaging applications.

Interrogating the Role of Receptor-Mediated Mechanisms: Biological Fate of Peptide-Functionalized Radiolabeled Gold Nanoparticles in Tumor Mice

To get a better insight on the transport mechanism of peptide-conjugated nanoparticles to tumors, we performed in vivo biological studies of bombesin (BBN) peptide functionalized gold nanoparticles (AuNPs) in human prostate tumor bearing mice. Initially, we sought to compare AuNPs with thiol derivatives of acyclic and macrocyclic chelators of DTPA and DOTA types. The DTPA derivatives were unable to provide a stable coordination of (67)Ga, and therefore, the functionalization with the BBN analogues was pursued for the DOTA-containing AuNPs. The DOTA-coated AuNPs were functionalized with BBN[7-14] using a unidentate cysteine group or a bidentate thioctic group to attach the peptide. AuNPs functionalized with thioctic-BBN displayed the highest in vitro cellular internalization (≈ 25%, 15 min) in gastrin releasing peptide (GRP) receptor expressing cancer cells. However, these results fail to translate to in vivo tumor uptake. Biodistribution studies following intravenous (IV) and intraperitoneal (IP) administration of nanoconjugates in tumor bearing mice indicated that the presence of BBN influences to some degree the biological profile of the nanoconstructs. For IV administration, the receptor-mediated pathway appears to be outweighed by the EPR effect. By contrast, in IP administration, it is reasoned that the GRPr-mediated mechanism plays a role in pancreas uptake.

Abstract 1903: Personalized diagnostics: Receptor specific gold nanorods used for accurate diagnosis of EGFR expression in human tumor tissues

Objective: The purpose of this study was to apply the enhanced surface chemistry and imaging properties of gold nanorods to the area of tumor protein diagnostics in order to give an accurate, quantifiable interpretation of a patient's biomarker status. The epidermal growth factor receptor (EGFR; HER1) is a cell surface receptor that regulates cell migration, adhesion, and proliferation. EGFR is commonly overexpressed in a variety of cancers. EGFR expression testing has been mandated by insurance companies in many areas before therapy can be given. Current methods of EGFR evaluation have been shown to be unreliable, thus EGFR was chosen as a target of interest for our studies.

Methods: Gold nanorods (GNR) of aspect ratio 3:4 were prepared using an established seed-mediated growth method. The GNR were then PEGylated and conjugated with a unique modified peptide that has shown specific affinity for the EGF receptor. The product was characterized to show stability and presence of surface-bound peptide. The compound known as GNR-1070 was used to examine correlations between EGFR expression and gold present on the membranes of human cell lines and paraffin-embedded tissue samples.

Results: In cell lines that are known to express EGFR, gold particles were identified bound to the membranes. The amount of bound gold correlated with the degree of EGFR expression of each cell line. Histochemical analysis of paraffin-embedded human tissue lines also correlated with the amount of gold bound to the membranes of the tissues.

Conclusion: Gold nanorods conjugated with receptor-specific peptides can be used to give an accurate evaluation of protein expression in human cell lines and tissue samples.

Citation Format: Chuck Caldwell, Ajit Zambre, Dhananjay Suresh, Gerald Arthur, Raghuraman Kannan. Personalized diagnostics: Receptor specific gold nanorods used for accurate diagnosis of EGFR expression in human tumor tissues. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1903. doi:10.1158/1538-7445.AM2014-1903

Selective X-ray contrast enhancement of the spleen of living mice mediated by gold nanorods

Gold nanomaterials (AuNPs) represent a promising new class of contrast agents for X-ray computed tomographic (CT) imaging in both research and clinical settings. These materials exhibit superior X-ray absorption properties compared with other iodinated agents, and thus require lower injection doses. Gold is nonimmunogenic and therefore contributes to safety profile in living specimens. Unfortunately, most reports on the use of AuNPs as X-ray CT enhancers only demonstrate marginal enhancement of the intended anatomical structure. In this study, we demonstrate the dramatic properties of gold nanorods (GNR) to serve as robust X-ray CT contrast-enhancing agent for selective imaging of the spleen. These organ-specific uptake properties were delineated by performing longitudinal CT imaging of living mice that were dosed with GNR at 2 day intervals. Rapid uptake in spleen was noted within 12 h of first systemic administration with a change in contrast enhancement of 90 Hounsfield units (ΔHU = 90) and with two subsequent injections a total contrast enhancement of over 200 HU was observed. The resulting images provide excellent contrast that will enable the detailed anatomical visualization and study of a range of pre-clinical models of spleen disease including infection and cancer.

Bombesin peptide conjugated gold nanocages internalize via clathrin mediated endocytosis

The nature of interaction and mechanism of internalization of receptor-avid peptide nanoparticles with cells is not yet completely understood. This article describes the cellular internalization mechanism and intracellular trafficking of peptide conjugated receptor targeted porous Gold nanocages (AuNCs) in cancer cells. We synthesized and characterized a library of AuNCs conjugated with bombesin (BBN) peptide. Evidence of selective affinity of AuNC-BBN toward gastrin releasing peptide receptors (GRPR) was obtained using radiolabeled competitive cell binding assay. Endocytic mechanism was investigated using cell inhibitor studies and monitored using optical and transmission electron microscopy (TEM). Results show AuNC-BBN uptake in PC3 cells is mediated by clathrin mediated endocytosis (CME). Indeed, in the presence of CME inhibitors, AuNC-BBN uptake in cells is reduced up to 84%. TEM images further confirm CME characteristic clathrin coated pits and lysosomal release of AuNCs. These results demonstrate that peptide ligands conjugated to the surface of nanoparticles maintain their target specificity. This bolsters the case for peptide robustness and its persisting functionality in intracellular vehicular delivery systems.

Synthesis and characterization of functional multicomponent nanosized gallium chelated gold crystals

Multicomponent nanomaterials containing Au, Ga, and a biomolecule have been synthesized. Compositional analysis of these nanoparticles was performed by using STEM-HAADF and EELS spectroscopy.

Novel di-tertiary-butyl phenylhydrazones as dual cyclooxygenase-2/5-lipoxygenase inhibitors: synthesis, COX/LOX inhibition, molecular modeling, and insights into their cytotoxicities

Although dual inhibition of Cyclooxygenase-2 (COX-2) and 5-Lipoxygenase (5-LOX) enzymes is highly effective than targeting COX or LOX alone, there are only a few reports of examining such compounds in case of colorectal cancers (CRC). In the present work we report that the novel di-tert-butyl phenol-based dual inhibitors DTPSAL, DTPBHZ, DTPINH, and DTPNHZ exhibit significant cytotoxicity against human CRC cell lines. Molecular docking studies revealed a good fit of these compounds in the COX-2 and 5-LOX protein cavities. The inhibitors show significant inhibition of COX-2 and 5-LOX activities and are effective against a panel of human colon cancer cell lines including HCA-7, HT-29, SW480 and intestinal Apc10.1 cells as well as the hyaluronan synthase-2 (Has2) enzyme over-expressing colon cancer cells, through inhibition of the Hyaluronan/CD44v6 cell survival pathway. Western blot analysis and qRT-PCR analyses indicated that the di-tert-butyl phenol-based dual inhibitors reduce the expression of COX-2, 5-LOX, and CD44v6 in human colon cancer HCA-7 cells, while the combination of CD44v6shRNA and DTPSAL has an additional inhibitory effect on CD44v6 mRNA expression. The synergistic inhibitory effect of Celecoxib and Licofelone on CD44v6 mRNA expression suggests that the present dual inhibitors down-regulate cyclooxygenase and lipoxygenase enzymes through CD44v6. The compounds also exhibited enhanced antiproliferative potency compared to standard dual COX/LOX inhibitor, viz. Licofelone. Importantly, the HA/CD44v6 antagonist CD44v6shRNA in combination with synthetic compounds had a sensitizing effect on the cancer cells which enhanced their antiproliferative potency, a finding which is crucial for the anti-proliferative potency of the novel synthetic di-tert-butyl phenol based dual COX-LOX inhibitors in colon cancer cells.

Nanoparticles and phage display selected peptides for imaging and therapy of cancer

Molecular imaging probes are a special class of pharmaceuticals that target specific biochemical signatures associated with disease and allow for noninvasive imaging on the molecular level. Because changes in biochemistry occur before diseases reach an advanced stage, molecular imaging probes make it possible to locate and stage disease, track the effectiveness of drugs, treat disease, monitor response, and select patients to allow for more personalized diagnosis and treatment of disease. Targeting agents radiolabeled with positron emitters are of interest due to their ability to quantitatively measure biodistribution and receptor expression to allow for optimal dose determinations. (68)Ga is a positron emitter, which allows for quantitative imaging through positron emission chromatography (PET). The availability of (68)Ga from a generator and its ability to form stable complexes with a variety of chelates hold promise for expanding PET utilization to facilities unable to afford their own cyclotron. Nanoparticles conjugated with various proteins and peptides derived from phage display that can be selectively targeted are being developed and evaluated for guided imaging and therapy. Herein we highlight some initial efforts in combining the enhanced selectivity of nanoparticles and peptides with (68)Ga for use as molecular imaging probes.

Green Nanotechnology from Brassicaceae

The interaction of cocktail of phytochemicals from broccoli with gold salt results in dual reduction and surface capping to produce well-defined stable and biocompatible gold nanoparticles (B-AuNPs). Broccoli phytochemicals–coated gold nanoparticles (B-AuNPs) have been fully characterized. Detailed in vitro stability in various biological fluids and affinity and selectivity for tumor cells have been investigated. The B-AuNPs showed significant in vitro cytotoxic effects against various cancer cells (MDA-MB-231, PC-3, U266, SkBr3, and T47D) as confirmed by 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) and flow cytometry apoptosis assays. Surface encapsulation of cocktail of broccoli phytochemicals on AuNPs facilitates the cellular internalization, thereby validating the in vitro therapeutic effects of these nanoparticles. Detailed analyses performed by combination of gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–tandem mass spectrometry (LC–MS–MS) have confirmed the presence of biologically active phytochemicals including glucoraphanin, phenethyl glucosinolates, quercetin, folic acid, vitamin C, allyl isothiocyanates, 2-phenylethyl isothiocyanates, and sulforaphane. The unique synergistic cocktail effects of B-AuNPs will provide new opportunities for generating biocompatible AuNPs for molecular imaging and therapeutic applications.

Functionalized radioactive gold nanoparticles in tumor therapy

The development of new treatment modalities that offer clinicians the ability to reduce sizes of tumor prior to surgical resection or to achieve complete ablation without surgery would be a significant medical breakthrough in the overall care and treatment of prostate cancer patients. The goal of our investigation is aimed at validating the hypothesis that Gum Arabic-functionalized radioactive gold nanoparticles (GA-(198) AuNP) have high affinity toward tumor vasculature. We hypothesized further that intratumoral delivery of the GA-(198) AuNP agent within prostate tumor will allow optimal therapeutic payload that will significantly or completely ablate tumor without side effects, in patients with hormone refractory prostate cancer. In order to evaluate the therapeutic efficacy of this new nanoceutical, GA-(198) AuNP was produced by stabilization of radioactive gold nanoparticles ((198) Au) with the FDA-approved glycoprotein, GA. This review will describe basic and clinical translation studies toward realization of the therapeutic potential and myriad of clinical applications of GA-(198) AuNP agent in treating prostate and various solid tumors in human cancer patients.

New Nanomedicine Approaches Using Gold-thioguanine Nanoconjugates as Metallo-ligands

Gold-thioguanine nanoconjugates (AuNP-TG) of size 3-4 nm were synthesized and the ratio between gold and 6-Thioguanine (TG) was estimated as ~1:1.5 using a cyanide digestion method and confirmed by flame atomic absorption spectroscopic analysis. AuNP-TG constructs showed high in vitro stability under different pH conditions and biologically relevant solutions for a period of 24 hours. Reaction of AuNP-TG with europium or platinum salts resulted in the formation of organized self-assembled metallo-networks.

Nanoscale sensor design via in situ labeling of gold nanoparticles onto protein scaffolds

A one-step method for synthesis of bioconjugated gold nanoparticles is reported. A non-toxic and biocompatible phosphorus based reducing agent was used for reduction of gold (III) and formation of nanoparticles. Physicochemical properties of protein-A stabilized gold nanoparticls were investigated. Result of immunoassay experiments confirmed the potential of the synthesized anti-protein-A conjugated gold nanoparticles for use as a simple and inexpensive test for quantitative screening of protein-A samples.