Nanoparticles aptamer-conjugated

Fig. 9 Aptamers conjugated gold nanoparticles. (Adapted from [49])...

Medley et al. have shown the use of aptamer-conjugated nanoparticles for cancer cell detection [50]. Herr et al. [51] have shown the rapid collection and detection of leukemia cells using a novel two-nanoparticle assay with aptamers as the molecular recognition element. 

Herr, J.K., Smith, J.E., Medley, C.D., Shang-guan, D., Tan, W. (2006). Aptamer-conjugated nanoparticles for selective collection and detection of cancer cells. Anal. Chem. 78,2918-2924... 

Chen X, Estevez MC, Zhu Z et al (2009) Using aptamer-conjugated fluorescence resonance energy transfer nanoparticles for multiplexed canco cell monitoring. Anal Chem 81 7009-7014... 

Recently, Kang et al. reported the development of the first aptamer-conjugated, multifunctional liposome nanostructure. Similar to the drug-encapsulated nanoparticles previously mentioned, PEG spacers were incorporated to increase the systemic circulation time of the liposome and well as to prevent its uptake by macrophages in the liver and other organs, thus increasing it delivery efficacy. 

Chang, M., Yang, C.-S., Huang, D.-M., 2011. Aptamer-conjugated DNA icosahedral nanoparticles as a carrier of doxorubicin for cancer therapy. ACS Nano 5 (8), 6156-6163. Charoenphol, R, Bermudez, H., 2014. Aptamer-targeted DNA nanostructures for therapeutic delivery. Mol. Pharm. 11 (5), 1721-1725. 

Wang Y, Liu B (2009) Conjugated polyelectrolyte sensitized fluorescent detection of thrombin in blood serum using aptamer-immobilized silica nanoparticles as the platform. Langmuir 25 12787-12793... 

In one study, PLG microspheres bound to DNA using a cryogenic double emulsion process and injected intramuscularly into mice were found to promote transgene expression for up to 174 days after injection, dependent upon microsphere mass. More recently nanoparticles were constructed from carboxy terminated, PEG modified PGL polymers. These particles were conjugated with an aptamer to the prostate specific membrane antigen and evaluated for in vivo biodistribution in an LNCaP (PSMA+) xenograft mouse model of prostate cancer. In this study, the aptamer caused a 3.77-fold increase in polymer concentration in the tumor tissue after retro-orbital injection (79). 

Tremendous efforts have been made to overcome these challenges, cationic liposome and positively charged polymers are currently being used as the most common method to complex with negatively charged siRNA for systemic delivery [30, 36]. Other in vivo delivery approaches include conjugation with cholesterol, aptamer, peptide complexation with antibody-protamine fusion protein or encapsulation in cyclodextrin nanoparticles [35, 37-39]. 

This chapter broadly describes the lead optimization activities relevant to the development of novel conjugate siRNA therapeutics for hepatic targets via subcutaneous administration. For specific information regarding other therapeutic oligonucleotide technologies (e.g., antisense, aptamer, CpG, anti-miR), specific nanoparticle-based delivery systems, or non-hepatic targeting, readers are directed elsewhere (Bennett and Swayze, 2010 Kole et al., 2012). 

J.L. Chavez, W. Lyon, N. Kelley-Loughnane, M.O. Stone, Theophylline detection using an aptamer and DNA-gold nanoparticle conjugates. Biosens. Bioelectron. 26 (2010) 23-28. 

Aptamer based biosensors, for example for recombinant human erythropoietin (as model analyte), can be made more sensitive by amplification with a boronic acid tethered gold nanoparticle that is then associated with an alkaline phosphatase to produce a redox active probe molecule. A similar re-usable bio-immuno-sensor has been suggested for carcinoembryonic antigen. A phenylboronic acid is assembled on gold to (reversibly) bind the antibody horseradish peroxidase conjugate. Interaction with the antigen slows down the hydrogen peroxide reduction. An HIV-1 immunoassay based on electroluminescence has been proposed by Zhou etaV In this process the... 

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