Studies on antibody were documented as early as in 1890. They are proteins found in blood or other body fluid of vertebrates, and are used by the immune system to identify and neutralize antigens (like foreign objects, pathogens like bacteria and virus etc). Antibodies are dominating the biomedical research field especially detection, imaging and inhibition of biological target molecules, and therapeutics so far. However, recently aptamer has been seen to compete with antibodies in all the above areas. Aptamers are single stranded oligonucleotides or peptides that fold into well defined three dimensional shapes, allowing them to bind their targets with high affinity and specificity. Aptamer technology is relatively new and discovered only in 1990. Because of synthetic origin and similar function as antibodies, they are often termed as chemical antibody. Within 25 years of discovery, the first generation of aptamer drug "Macugen" is already marketed and available for public use. The Global market for aptamer was $236 million in 2010 and is expected to be valued at nearly $1.8 billion by 2014, with a growing compound annual growth rate of 67.5%. Various drugs being on the pipeline for clinical trials this emerging field of medical biotechnology is raising significant interest. This article gives an overview how aptamers are similar yet distinctly different from antibodies in terms of synthesis, handling, and applicability. (+info)
Assembly of aptamer switch probes and photosensitizer on gold nanorods for targeted photothermal and photodynamic cancer therapy.
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Single-step nanoplasmonic VEGF165 aptasensor for early cancer diagnosis.
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Early cancer diagnosis is very important for the prevention or mitigation of metastasis. However, effective and efficient methods are needed to improve the diagnosis and assessment of cancer. Here, we report a single-step detection method using a nanoplasmonic aptamer sensor (aptasensor), targeting a vascular endothelial growth factor-165 (VEGF(165)), a predominant biomarker of cancer angiogenesis. Our single-step detection is accomplished by (1) specific target recognition by an aptamer-target molecule interaction and (2) direct readouts of the target recognition. The readout is achieved by inactivation of surface plasmon enhancement of fluorescent probes preattached to the aptamers. Our aptasensor provides the appropriate sensitivity for clinical diagnostics with a wide range of linear detection from 25 pg/mL to 25 mug/mL (=from 1.25 pM to 1.25 muM), high specificity for VEGF(165) against PDGF-BB, osteopontin (OPN), VEGF(121), NaCl, and temporal/thermal/biological stability. In experiments with 100% serum and saliva from clinical samples, readouts of the aptasensor and an ELISA for VEGF(165) show good agreement within the limit of the ELISA kit. We envision that our developed aptasensor holds utilities for point-of-care cancer prognostics by incorporating simplicity in detection, low-cost for test, and required small sample volumes. (+info)
COP9 signalosome component JAB1/CSN5 is necessary for T cell signaling through LFA-1 and HIV-1 replication.
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Calcineurin A versus NS5A-TP2/HD domain containing 2: a case study of site-directed low-frequency random mutagenesis for dissecting target specificity of peptide aptamers.
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