Aptamers are a class of single oligonucleotide molecules(DNA or RNA)that are screened from random DNA or RNA oligonucleotide chain libraries by the systemic evolution of ligands by exponential enrichment technology.Th...Aptamers are a class of single oligonucleotide molecules(DNA or RNA)that are screened from random DNA or RNA oligonucleotide chain libraries by the systemic evolution of ligands by exponential enrichment technology.The selected aptamers are capable of specifically binding to different targeting molecules,which is achieved by the three-dimensional structure of aptamers.Aptamers are similar in function to monoclonal antibodies,and therefore,they are also referred to as"chemical antibodies".Due to their high affinity and specificity and low immunogenicity,aptamers are topics of intense interest in today's biological targeting research especially in tumor research.They not only have high potential for clinical advances in tumor targeting detection but also are highly promising as targeted tumor drug carriers for use in tumor therapy.Various experimental studies have shown that aptamer-based diagnostic and therapeutic methods for liver cancer have great potential for application.This paper summarizes the structure,characteristics,and screening methods of aptamers and reviews the recent research progress on nucleic acid aptamers in the targeted diagnosis and treatment of liver cancer.展开更多
Hepatitis B virus surface antigen （HBsAg）, a specific antigen on the membrane of Hepatitis B virus （HBV）-infected cells, provides a perfect target for therapeutic drugs. The development of reagents with high affin...Hepatitis B virus surface antigen （HBsAg）, a specific antigen on the membrane of Hepatitis B virus （HBV）-infected cells, provides a perfect target for therapeutic drugs. The development of reagents with high affinity and specificity to the HBsAg is of great significance to the early-stage diagnosis and treatment of HBV infection. Herein, we report the selection of RNA aptamers that can specifically bind to HBsAg protein and HBsAg-positive hepatocytes. One high affinity aptamer, HBs-A22, was isolated from an initial 115 met library of -1.1 ×10^15 random-sequence RNA molecules using the SELEX procedure. The selected aptamer HBs-A22 bound specifically to hepatoma cell line HepG2.2.15 that expresses HBsAg but did not bind to HBsAg-devoid HepG2 cells. This is the first reported RNA aptamer which could bind to a HBV specific antigen. This newly isolated aptamer could be modified to deliver imaging, diagnostic, and therapeutic agents targeted at HBV-infected cells.展开更多
Aptamers are specific nucleic acid sequences that can bind to a wide range of nucleic acid and non-nucleic acid targets with high affinity and specificity. Nucleic acid aptamers are selected in vitro from single stran...Aptamers are specific nucleic acid sequences that can bind to a wide range of nucleic acid and non-nucleic acid targets with high affinity and specificity. Nucleic acid aptamers are selected in vitro from single stranded DNA or RNA ligands containing random sequences of up to a few hundred nucleotides. Systematic evolution of ligands by exponential enrichment （SELEX） was used to select and PCR amplify DNA sequences （aptamers） capable of binding to and detecting Listeria monocytogenes, one of the major food-borne pathogens. A simplified affinity separation approach was employed, in which L. monocytogenes in exponential （log） phase of growth was used as the separation target. A fluorescently-labeled aptamer assay scheme was devised for detecting L. monoeytogenes. This report described a novel approach to the detection of L. monocytogenes using DNA aptamers. Aptamers were developed by nine rounds of SELEX. A high affinity aptamer was successfully selected from the initial random DNA pool, and its secondary structure was also investigated. One of aptamers named e01 with the highest affinity was further tested in aptamer-peroxidase and aptamer-fluorescence staining protocols. This study has proved the principle that the whole-cell SELEX could be a promising technique to design aptamer-based molecular probes for dectection of pathogenic microorganisms without tedious isolation and purification of complex markers or targets.展开更多
动物疫病的暴发不仅造成了巨大损失,也严重阻碍着人工养殖业的健康可持续发展,因此亟须针对疫病病原开发快速检测技术和病原防控技术来预防病害的暴发。核酸适体(aptamer)是针对特定靶标,利用指数富集配基系统进化技术(systematic evolu...动物疫病的暴发不仅造成了巨大损失,也严重阻碍着人工养殖业的健康可持续发展,因此亟须针对疫病病原开发快速检测技术和病原防控技术来预防病害的暴发。核酸适体(aptamer)是针对特定靶标,利用指数富集配基系统进化技术(systematic evolution of ligands by exponential enrichment,SELEX)筛选得到具有高亲和力和高特异性的功能性单链寡核苷酸。本文结合国内外研究,阐述了核酸适体的优势以及其在人工养殖动物病原微生物防控中的研究进展,同时重点讨论了核酸适体在应用方面的5种挑战,(1)核酸适体筛选技术的局限性;(2)核酸适体在治疗方面缺乏稳定性与安全性;(3)核酸适体在生物体内如何持续性发挥靶向治疗作用;(4)核酸适体在活体实验中的精确性有待提高;(5)核酸适体与其他检测方法能否串联,从而构建全面性的检测平台。目前核酸适体针对养殖动物病原领域的研究只是刚刚起步,在快速检测与靶向治疗方面具有广阔的应用前景。展开更多
文摘Aptamers are a class of single oligonucleotide molecules(DNA or RNA)that are screened from random DNA or RNA oligonucleotide chain libraries by the systemic evolution of ligands by exponential enrichment technology.The selected aptamers are capable of specifically binding to different targeting molecules,which is achieved by the three-dimensional structure of aptamers.Aptamers are similar in function to monoclonal antibodies,and therefore,they are also referred to as"chemical antibodies".Due to their high affinity and specificity and low immunogenicity,aptamers are topics of intense interest in today's biological targeting research especially in tumor research.They not only have high potential for clinical advances in tumor targeting detection but also are highly promising as targeted tumor drug carriers for use in tumor therapy.Various experimental studies have shown that aptamer-based diagnostic and therapeutic methods for liver cancer have great potential for application.This paper summarizes the structure,characteristics,and screening methods of aptamers and reviews the recent research progress on nucleic acid aptamers in the targeted diagnosis and treatment of liver cancer.
基金National Mega Research Program of China(2008ZX10002-011)National Natural Science Foundation of China(30700701)National High Tech-nology Research and Development program of China(2006AA02Z128)
文摘Hepatitis B virus surface antigen （HBsAg）, a specific antigen on the membrane of Hepatitis B virus （HBV）-infected cells, provides a perfect target for therapeutic drugs. The development of reagents with high affinity and specificity to the HBsAg is of great significance to the early-stage diagnosis and treatment of HBV infection. Herein, we report the selection of RNA aptamers that can specifically bind to HBsAg protein and HBsAg-positive hepatocytes. One high affinity aptamer, HBs-A22, was isolated from an initial 115 met library of -1.1 ×10^15 random-sequence RNA molecules using the SELEX procedure. The selected aptamer HBs-A22 bound specifically to hepatoma cell line HepG2.2.15 that expresses HBsAg but did not bind to HBsAg-devoid HepG2 cells. This is the first reported RNA aptamer which could bind to a HBV specific antigen. This newly isolated aptamer could be modified to deliver imaging, diagnostic, and therapeutic agents targeted at HBV-infected cells.
文摘Aptamers are specific nucleic acid sequences that can bind to a wide range of nucleic acid and non-nucleic acid targets with high affinity and specificity. Nucleic acid aptamers are selected in vitro from single stranded DNA or RNA ligands containing random sequences of up to a few hundred nucleotides. Systematic evolution of ligands by exponential enrichment （SELEX） was used to select and PCR amplify DNA sequences （aptamers） capable of binding to and detecting Listeria monocytogenes, one of the major food-borne pathogens. A simplified affinity separation approach was employed, in which L. monocytogenes in exponential （log） phase of growth was used as the separation target. A fluorescently-labeled aptamer assay scheme was devised for detecting L. monoeytogenes. This report described a novel approach to the detection of L. monocytogenes using DNA aptamers. Aptamers were developed by nine rounds of SELEX. A high affinity aptamer was successfully selected from the initial random DNA pool, and its secondary structure was also investigated. One of aptamers named e01 with the highest affinity was further tested in aptamer-peroxidase and aptamer-fluorescence staining protocols. This study has proved the principle that the whole-cell SELEX could be a promising technique to design aptamer-based molecular probes for dectection of pathogenic microorganisms without tedious isolation and purification of complex markers or targets.
文摘动物疫病的暴发不仅造成了巨大损失,也严重阻碍着人工养殖业的健康可持续发展,因此亟须针对疫病病原开发快速检测技术和病原防控技术来预防病害的暴发。核酸适体(aptamer)是针对特定靶标,利用指数富集配基系统进化技术(systematic evolution of ligands by exponential enrichment,SELEX)筛选得到具有高亲和力和高特异性的功能性单链寡核苷酸。本文结合国内外研究,阐述了核酸适体的优势以及其在人工养殖动物病原微生物防控中的研究进展,同时重点讨论了核酸适体在应用方面的5种挑战,(1)核酸适体筛选技术的局限性;(2)核酸适体在治疗方面缺乏稳定性与安全性;(3)核酸适体在生物体内如何持续性发挥靶向治疗作用;(4)核酸适体在活体实验中的精确性有待提高;(5)核酸适体与其他检测方法能否串联,从而构建全面性的检测平台。目前核酸适体针对养殖动物病原领域的研究只是刚刚起步,在快速检测与靶向治疗方面具有广阔的应用前景。
