Liquid biopsy is a technology that exhibits potential to detect cancer early,monitor therapies,and predict cancer prognosis due to its unique characteristics,including noninvasive sampling and real-time analysis.Circu...Liquid biopsy is a technology that exhibits potential to detect cancer early,monitor therapies,and predict cancer prognosis due to its unique characteristics,including noninvasive sampling and real-time analysis.Circulating tumor cells(CTCs)and extracellular vesicles(EVs)are two important components of circulating targets,carrying substantial disease-related molecular information and playing a key role in liquid biopsy.Aptamers are single-stranded oligonucleotides with superior affinity and specificity,and they can bind to targets by folding into unique tertiary structures.Aptamer-based microfluidic platforms offer new ways to enhance the purity and capture efficiency of CTCs and EVs by combining the advantages of microfluidic chips as isolation platforms and aptamers as recognition tools.In this review,we first briefly introduce some new strategies for aptamer discovery based on traditional and aptamer-based microfluidic approaches.Then,we subsequently summarize the progress of aptamer-based microfluidics for CTC and EV detection.Finally,we offer an outlook on the future directional challenges of aptamer-based microfluidics for circulating targets in clinical applications.展开更多
Background:Raloxifene,a selective estrogen receptor modulator,is also known to be a lysosomotropic agent.The bioavailability of raloxifene is around 2%due to extensive hepatic transport.Exosomes are nanosized vesicles...Background:Raloxifene,a selective estrogen receptor modulator,is also known to be a lysosomotropic agent.The bioavailability of raloxifene is around 2%due to extensive hepatic transport.Exosomes are nanosized vesicles that are naturally released from cells.Method:In this study,exosomes released from HeLa cervical cancer cells were loaded with raloxifene to increase its bioavailability,and an aptamer was attached to the exosome membrane for targeting only HeLa cells.Characterization of exosomes isolated from HeLa cells was performed by transmission electron microscopy,zeta sizer,and western blotting.In addition,the cytotoxic,apoptotic,autophagic,and lysosomotropic effects of the prepared Exo-Apt-Ral formulation on HeLa cervical cancer cells were investigated.Results:According to zeta analysis,the sizes of the empty exosome and Exo-Apt-Ral formulation were measured as 66±12 and 120±21 nm,respectively.There was a rise in the lysosomal permeability of HeLa cells after the Exo-Apt-Ral application.In addition,both apoptotic and autophagic death mechanisms were triggered in HeLa cells after the Exo-Apt-Ral application.Conclusion:This study showed that raloxifene functionalized by loading into aptamer-bound exosomes can be a new targeted drug carrier system for cervical cancer.展开更多
Aptamers as a kind of biological recognition element have shown great potential in monitoring and the rapid quantification of organophosphorus pesticides(OPPs). However, molecules of OPPs are structurally similar and ...Aptamers as a kind of biological recognition element have shown great potential in monitoring and the rapid quantification of organophosphorus pesticides(OPPs). However, molecules of OPPs are structurally similar and original aptamers selected by systematic evolution of ligands by exponential enrichment are usually long-chain bases, which hamper the further application under OPPs-aptamer recognition. The aim of the research was to develop a new strategy to design oligonucleotide sequences for binding OPPs by combination of experimental and molecular modeling methods. 3D models of aptamers binding OPPs were constructed, and binding energy and the most probable binding site for the OPPs were then determined by molecular docking, and the binding sites were further confirmed by the results of 2-AP replaced experiments. Based on the docking results, a new aptamer for detection 4 representative OPPs with only 29 bases was designed by reasonable truncation and mutation of the reported aptamer(named S4-29). The interaction between this new aptamer and OPPs were analyzed by molecular docking, microscale thermophoresis, circular dichroism and fluorometric analysis. The results revealed that the new aptamer exhibit more superior recognition performance to OPPs, which can be promote the monitoring ability of OPPs contaminations in food.展开更多
Food safety is a major issue to public health and have attracted global attention.Fast,sensitive,and reliable detection methods for food hazardous substances is highly desirable.Aptamers which can bind to the target m...Food safety is a major issue to public health and have attracted global attention.Fast,sensitive,and reliable detection methods for food hazardous substances is highly desirable.Aptamers which can bind to the target molecules with high affinity and specificity represent an attractive tool for the recognition of food hazardous substances,which play an important role in the development and application of new food safety detection technology.But current assays for characterizing small molecule-aptamer binding are limited by either the mass sensitivity or the size differentiation ability.Herein,we proposed a comprehensive method for assessing the dissociation equilibria of small molecule-aptamer,which is immobilized-free under ambient conditions.The design employs the Le Chatelier’s principle and could be used to effectively measure small molecule-aptamer interactions.ATP binding aptamer and anti-aflatoxin B1 aptamer were used as the model system to determine their affinity,in which their dissociation equilibria measurements are in excellent close to their previous work.Due to the simplicity and sensitivity of this new method,we believe that it could be recommended as an effective tool for characterizing small molecule-aptamer interactions and promote the further application of small molecular aptamer in food safety.展开更多
Staphylococcus aureus is a gram-staining positive cocci bacillus baterium and also one of the foodborne pathogens, which is a serious potential hazard to human health and food safety. We constructed an electroche...Staphylococcus aureus is a gram-staining positive cocci bacillus baterium and also one of the foodborne pathogens, which is a serious potential hazard to human health and food safety. We constructed an electrochemical biosensor for the detection of S. aureus based on nucleic acid aptamers to achieve highly specific detection of S. aureus. The detection of S. aureus was realized by using Aptamer (Apt) to capture S. aureus, which resulted in a change in the spatial conformation of Apt and a decrease in the electrochemical signal. Under the optimized experimental conditions, the detected electrochemical signals were positively correlated with the concentration of S. aureus with a linear range of 1 × 10<sup>1</sup> - 1 × 10<sup>5</sup> CFU/mL, a detection limit of 4.76 CFU/mL, and an experimental recovery of 97.43% - 99.37%. Therefore, we successfully constructed an electrochemical biosensor for the specific detection of S. aureus, which has the advantages of high specificity, sensitive detection and convenient operation.展开更多
Ergot alkaloids are mycotoxins which can be found in food based on cereal-crops, due to a contamination of plants by fungi of the genus Claviceps. The ingestion of ergot contaminated cereal crops can lead to a severe ...Ergot alkaloids are mycotoxins which can be found in food based on cereal-crops, due to a contamination of plants by fungi of the genus Claviceps. The ingestion of ergot contaminated cereal crops can lead to a severe poisoning known as ergotism. For food and feed safety purposes, the extraction of ergot alkaloids from ergot contaminated flour was investigated. For the specific recognition of ergot alkaloids, DNA aptamer ligands specially selected for ergot alkaloids were grafted onto silica gel in order to construct a specific solid phase extraction system. The aptamer-functionalized silica gels were used to extract ergot alkaloids from a contaminated rye feed sample. The presence of ergot alkaloids eluted from the aptamer-functionalized silica gels was analyzed using LC-QTOF-MS. By using this simple system, it was possible to specifically extract ergosine, ergokryptine and ergocornine from an ergot contaminated rye feed sample. This aptamer-based extraction tool shows the applicability of aptamers for the specific extraction of toxins or natural compounds from turbid matrices in a one-step procedure.展开更多
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
Okadaic acid(OA)is a typical marine toxin with strong toxicity causing diarrheic shellfish poisoning(DSP).Aptamers show great advantages in toxin detection and attract increasing attentions in the field of food analys...Okadaic acid(OA)is a typical marine toxin with strong toxicity causing diarrheic shellfish poisoning(DSP).Aptamers show great advantages in toxin detection and attract increasing attentions in the field of food analysis.In this study,a label-free col-orimetric aptasensor was constructed for visual and rapid detection of OA in shellfish.To exploit the binding capability of the anti-OA aptamer,the inherent molecular recognition mechanism of aptamer and OA was studied,based on molecular docking,fluorescent assay,and biolayer interferometry.Consistent results showed that the stem-loop near the 3’terminal of the aptamer exhibit dominate binding capacity.Based on the revealed recognition information,the aptamer was thus rationally utilized and combined with AuNPs and cationic polymer polydiallyl dimethyl ammonium chloride(PDDA)for the development of the label-free colorimetric aptasensor,in which the 3’terminal was thoroughly exposed to OA.The aptasensor provided robust performance with a linear detection range of 100-1200 nmol L-1,a limit of detection of 41.30 nmol L-1,recovery rates of 91.6%-106.2%,as well as a high selectivity towards OA in shellfish samples.The whole detection process can be completed within 1 h.To our best knowledge,this is the first time that the anti-OA aptamer was thoroughly studied,and a label-free colorimetric aptasensor was rationally designed in this way.This study not only provides a rapid detection method for highly sensitive and specific detection of OA,but also serves as a reference for the design of efficient aptasensors in the future.展开更多
Lymphomas are cancers that arise from white blood cells and usually present as solid tumors. Treatment of lymphoma often involves chemotherapy, and can also include radiotherapy and/or bone marrow transplantation. The...Lymphomas are cancers that arise from white blood cells and usually present as solid tumors. Treatment of lymphoma often involves chemotherapy, and can also include radiotherapy and/or bone marrow transplantation. There is an unquestioned need for more effective therapies and diagnostic tool for lymphoma. Aptamers are single stranded DNA or RNA oligonucleotides whose three-dimensional structures are dictated by their sequences. The immense diversity in function and structure of nucleic acids enable numerous aptamers to be generated through an iterative in vitro selection technique known as Systematic Evolution of Ligands by EXponential enrichment (SELEX). Aptamers have several biochemical properties that make them attractive tools for use as potential diagnostic and pharmacologic agents. Isolated aptamers may directly inhibit the function of target proteins, or they can also be formulated for use as delivery agents for other therapeutic or imaging cargoes. More complex aptamer identification methods, using whole cancer cells (Cell-SELEX), may identify novel targets and aptamers to affect them. This review focuses on recent advances in the use of nucleic acid aptamers as diagnostic and therapeutic agents and as targeted delivery carriers that are relevant to lymphoma. Some representative examples are also discussed.展开更多
Despite intensive research,most neurodegenerative diseases cannot be cured and for some of them no treatment is available to increase survival or quality of life.Among the latter are prion diseases,fatal and transmiss...Despite intensive research,most neurodegenerative diseases cannot be cured and for some of them no treatment is available to increase survival or quality of life.Among the latter are prion diseases,fatal and transmissible neurodegenerative diseases of humans and other animals.Exam-展开更多
Ochratoxin A(OTA),one of the most dangerous mycotoxins for human health,has been subjected to numerous studies for separation and detection in minimal amounts.Aptamers as novel recognition elements have been employed ...Ochratoxin A(OTA),one of the most dangerous mycotoxins for human health,has been subjected to numerous studies for separation and detection in minimal amounts.Aptamers as novel recognition elements have been employed to fabricate ultrasensitive biosensors for the detection of OTA and designing delicate analytical tools.This review attempted to comprehensively examine all reported aptamer-based detection and separation platforms for ochratoxin.The most relevant databases were considered to discover all specific aptamers for dealing with OTA.Aptamer-based detection and separation devices specified for OTA were searched for,analyzed,discussed,and classified based on their specifications.The optical aptasensors have gathered a higher interest than electrochemical aptasensors,which can achieve a lower limit of detections.Moreover,some extraction platforms based on these aptamers were also found.However,aptamer-based devices seem to have some challenges in their application.展开更多
Background: Nine proteins were identified as putative profibrotic biomarkers in systemic sclerosis (SSc) and an unrelated fibrotic disease in a previously published proteomic study. As the majority of these proteins w...Background: Nine proteins were identified as putative profibrotic biomarkers in systemic sclerosis (SSc) and an unrelated fibrotic disease in a previously published proteomic study. As the majority of these proteins were orphans of commercially available antibodies, the nine proteins were investigated to determine whether binding peptide aptamers of the Stefin A quadruple mutant-Tracy variant (referred to as “affimers”) could be validated by enzyme linked immunosorbant assay (ELISA) to allow the quantification of these candidate biomarkers in the sera of SSc patients. Materials and Methods: Candidate biomarker peptides were analysed by high throughput affimer microarray to identify binding affimers. Two candidate biomarkers were prioritised, and binding affimers were expressed from genetically modified BL21 competent E. coli strains and purified. These affimers were used in indirect ELISA, and then sandwich ELISA formats against the candidate biomarker recombinant proteins osteonectin and pigment epi-thetlium-derived factor (PEDF). Results: 39 affimers were identified as binders for eight of the nine candidate biomarker peptides were by affimer microarray;six for osteonectin and eleven for PEDF. Two of the six and all eleven were able to recognize physiological concentrations (5 and 1 μg·ml﹣1) of osteonectin and PEDF, respectively by indirect ELISA. In sandwich ELISA format: two affimers were able to detect recombinant PEDF;however, the two affimers identified in indirect ELISA were unable to recognise recombinant osteonectin, and were thus hypothesised to bind to osteonectin at the same binding site. Discussion: SSc is currently an orphan of fully validated biomarkers, which is required for the development of stratified medicine in this field. This approach has laid the groundwork for an affimer based on multiplexed assay, to validate biomarkers in the sera of SSc patients in the future.展开更多
Acute myocardial infarction(AMI)is a major health problem leading to high rates of mortality and morbidity.Biomarker cardiac troponin I(cTnI)has shown high sensitivity and specificity towards AMI detection,and has bee...Acute myocardial infarction(AMI)is a major health problem leading to high rates of mortality and morbidity.Biomarker cardiac troponin I(cTnI)has shown high sensitivity and specificity towards AMI detection,and has been regarded as"gold standard".An ultrasensitive method to detectcTnI with low concentration in human fluid is essential.In this paper,we developed an aptamer-based assay coupled with rolling circle amplification(RCA)and molecular beacon probe for sensitive detection ofcTnI.In this strategy,aptamer acts as a bridge to communicate between oligonucleotides andcTnI.RCA reaction produces a single-stranded tandem repeated copy of the circular template,which are recognized by fluorescence molecular beacon probe.With this strategy,highly sensitive and specific detection of cTnI was realized with the lowest detectable concentration of 7.24 pg/m L.The developed aptamer-RCA assay can be a promising tool in clinical samples analysis.The assay can also analyze other disease-related biomarkers by replacing the aptamer.展开更多
Objective:To isolate and characterize RNA aptamers that are specific to human CD36 protein using systematic evolution of ligands by exponential enrichment(SELEX)technology to identify candidates for adjunct therapy to...Objective:To isolate and characterize RNA aptamers that are specific to human CD36 protein using systematic evolution of ligands by exponential enrichment(SELEX)technology to identify candidates for adjunct therapy to reverse the binding of Plasmodiuminfected erythrocytes.Methods:RNA aptamers were isolated using nitrocellulose membrane-based SELEX and binding analysis was screened using an electrophoretic mobility shift assay and enzyme-linked oligonucleotide assay.Results:Thirteen cycles of nitrocellulose membrane-based SELEX yielded three aptamers(RC60,RC25,RC04)exhibiting high binding against CD36 protein as shown on electrophoretic mobility shift assay.The sequence analysis revealed a G-quadruplex sequence within all the isolated aptamers that might contribute to aptamer binding and thermodynamic stability.The specificity assay further showed that RC60 and RC25 were highly specific to CD36.The competitive inhibition assay demonstrated that RC60 and RC25 shared a similar binding epitope recognized by m Ab FA6-152,a specific monoclonal antibody against CD36.Conclusions:RC60 and RC25 are promising candidates as anticytoadherence for severe malaria adjunct therapy.展开更多
AIM:To confirm whether exosome-mediated delivery of aptamer S58(Exo-S58) has a better antifibrotic effect than naked S58 in human conjunctival fibroblasts(HCon Fs) and a rat glaucoma filtration surgery(GFS) model.METH...AIM:To confirm whether exosome-mediated delivery of aptamer S58(Exo-S58) has a better antifibrotic effect than naked S58 in human conjunctival fibroblasts(HCon Fs) and a rat glaucoma filtration surgery(GFS) model.METHODS:To enhance the effective reaction time of aptamer S58 in vivo, we loaded aptamer S58 into exosomes derived from HEK293 T cells by PEI transfection to determine the effect of Exo-S58 in HCon Fs and a rat GFS model.RESULTS:Exo-S58 can significantly reduce cell proliferation, migration and fibrosis in TGF-β2-induced HCon Fs. In an in vivo experiment, Exo-S58 treatment prolonged filtering bleb retention and reduced fibrosis compared with naked S58 treatment in GFS rats.CONCLUSION:The exosomes are safe and valid carriers to deliver aptamers. Furthermore, Exo-S58 exhibited superior antifibrotic effect than naked S58 both in HCon Fs cells and rat GFS models.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.:82003710 and 82173808)the Natural Science Foundation of Guangdong Province(Grant Nos.:2020A1515010075 and 2021B1515020100)+3 种基金the Project of Educational Commission of Guangdong Province(Grant No.:2021ZDZX2012)the Guangzhou Basic and Applied Basic Research Project(Grant No.:2023A04J1163)the National Key Clinical Specialty Construction Project(Clinical Pharmacy)High-Level Clinical Key Specialty(Clinical Pharmacy)in Guangdong Province,China.
文摘Liquid biopsy is a technology that exhibits potential to detect cancer early,monitor therapies,and predict cancer prognosis due to its unique characteristics,including noninvasive sampling and real-time analysis.Circulating tumor cells(CTCs)and extracellular vesicles(EVs)are two important components of circulating targets,carrying substantial disease-related molecular information and playing a key role in liquid biopsy.Aptamers are single-stranded oligonucleotides with superior affinity and specificity,and they can bind to targets by folding into unique tertiary structures.Aptamer-based microfluidic platforms offer new ways to enhance the purity and capture efficiency of CTCs and EVs by combining the advantages of microfluidic chips as isolation platforms and aptamers as recognition tools.In this review,we first briefly introduce some new strategies for aptamer discovery based on traditional and aptamer-based microfluidic approaches.Then,we subsequently summarize the progress of aptamer-based microfluidics for CTC and EV detection.Finally,we offer an outlook on the future directional challenges of aptamer-based microfluidics for circulating targets in clinical applications.
基金supported by a Grant(221S945)from the Scientific and Technological Research Council of Turkey(TUBITAK)an Aydin Adnan Menderes University Research Grant(ADU-TPF-20041).
文摘Background:Raloxifene,a selective estrogen receptor modulator,is also known to be a lysosomotropic agent.The bioavailability of raloxifene is around 2%due to extensive hepatic transport.Exosomes are nanosized vesicles that are naturally released from cells.Method:In this study,exosomes released from HeLa cervical cancer cells were loaded with raloxifene to increase its bioavailability,and an aptamer was attached to the exosome membrane for targeting only HeLa cells.Characterization of exosomes isolated from HeLa cells was performed by transmission electron microscopy,zeta sizer,and western blotting.In addition,the cytotoxic,apoptotic,autophagic,and lysosomotropic effects of the prepared Exo-Apt-Ral formulation on HeLa cervical cancer cells were investigated.Results:According to zeta analysis,the sizes of the empty exosome and Exo-Apt-Ral formulation were measured as 66±12 and 120±21 nm,respectively.There was a rise in the lysosomal permeability of HeLa cells after the Exo-Apt-Ral application.In addition,both apoptotic and autophagic death mechanisms were triggered in HeLa cells after the Exo-Apt-Ral application.Conclusion:This study showed that raloxifene functionalized by loading into aptamer-bound exosomes can be a new targeted drug carrier system for cervical cancer.
基金supported by the National Natural Science Foundation of China (31801647)Sichuan Science and Technology Program (2018JY0194,2020YFN0153,2020YFN0151)。
文摘Aptamers as a kind of biological recognition element have shown great potential in monitoring and the rapid quantification of organophosphorus pesticides(OPPs). However, molecules of OPPs are structurally similar and original aptamers selected by systematic evolution of ligands by exponential enrichment are usually long-chain bases, which hamper the further application under OPPs-aptamer recognition. The aim of the research was to develop a new strategy to design oligonucleotide sequences for binding OPPs by combination of experimental and molecular modeling methods. 3D models of aptamers binding OPPs were constructed, and binding energy and the most probable binding site for the OPPs were then determined by molecular docking, and the binding sites were further confirmed by the results of 2-AP replaced experiments. Based on the docking results, a new aptamer for detection 4 representative OPPs with only 29 bases was designed by reasonable truncation and mutation of the reported aptamer(named S4-29). The interaction between this new aptamer and OPPs were analyzed by molecular docking, microscale thermophoresis, circular dichroism and fluorometric analysis. The results revealed that the new aptamer exhibit more superior recognition performance to OPPs, which can be promote the monitoring ability of OPPs contaminations in food.
基金supported by the National Key R&D Program of China(2017YFC1600603)the Funds for Huangshan Professorship of Hefei University of Technology(407-037019).
文摘Food safety is a major issue to public health and have attracted global attention.Fast,sensitive,and reliable detection methods for food hazardous substances is highly desirable.Aptamers which can bind to the target molecules with high affinity and specificity represent an attractive tool for the recognition of food hazardous substances,which play an important role in the development and application of new food safety detection technology.But current assays for characterizing small molecule-aptamer binding are limited by either the mass sensitivity or the size differentiation ability.Herein,we proposed a comprehensive method for assessing the dissociation equilibria of small molecule-aptamer,which is immobilized-free under ambient conditions.The design employs the Le Chatelier’s principle and could be used to effectively measure small molecule-aptamer interactions.ATP binding aptamer and anti-aflatoxin B1 aptamer were used as the model system to determine their affinity,in which their dissociation equilibria measurements are in excellent close to their previous work.Due to the simplicity and sensitivity of this new method,we believe that it could be recommended as an effective tool for characterizing small molecule-aptamer interactions and promote the further application of small molecular aptamer in food safety.
文摘Staphylococcus aureus is a gram-staining positive cocci bacillus baterium and also one of the foodborne pathogens, which is a serious potential hazard to human health and food safety. We constructed an electrochemical biosensor for the detection of S. aureus based on nucleic acid aptamers to achieve highly specific detection of S. aureus. The detection of S. aureus was realized by using Aptamer (Apt) to capture S. aureus, which resulted in a change in the spatial conformation of Apt and a decrease in the electrochemical signal. Under the optimized experimental conditions, the detected electrochemical signals were positively correlated with the concentration of S. aureus with a linear range of 1 × 10<sup>1</sup> - 1 × 10<sup>5</sup> CFU/mL, a detection limit of 4.76 CFU/mL, and an experimental recovery of 97.43% - 99.37%. Therefore, we successfully constructed an electrochemical biosensor for the specific detection of S. aureus, which has the advantages of high specificity, sensitive detection and convenient operation.
文摘Ergot alkaloids are mycotoxins which can be found in food based on cereal-crops, due to a contamination of plants by fungi of the genus Claviceps. The ingestion of ergot contaminated cereal crops can lead to a severe poisoning known as ergotism. For food and feed safety purposes, the extraction of ergot alkaloids from ergot contaminated flour was investigated. For the specific recognition of ergot alkaloids, DNA aptamer ligands specially selected for ergot alkaloids were grafted onto silica gel in order to construct a specific solid phase extraction system. The aptamer-functionalized silica gels were used to extract ergot alkaloids from a contaminated rye feed sample. The presence of ergot alkaloids eluted from the aptamer-functionalized silica gels was analyzed using LC-QTOF-MS. By using this simple system, it was possible to specifically extract ergosine, ergokryptine and ergocornine from an ergot contaminated rye feed sample. This aptamer-based extraction tool shows the applicability of aptamers for the specific extraction of toxins or natural compounds from turbid matrices in a one-step procedure.
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funded by the National Natural Sci-ence Foundation of China(No.31801620).
文摘Okadaic acid(OA)is a typical marine toxin with strong toxicity causing diarrheic shellfish poisoning(DSP).Aptamers show great advantages in toxin detection and attract increasing attentions in the field of food analysis.In this study,a label-free col-orimetric aptasensor was constructed for visual and rapid detection of OA in shellfish.To exploit the binding capability of the anti-OA aptamer,the inherent molecular recognition mechanism of aptamer and OA was studied,based on molecular docking,fluorescent assay,and biolayer interferometry.Consistent results showed that the stem-loop near the 3’terminal of the aptamer exhibit dominate binding capacity.Based on the revealed recognition information,the aptamer was thus rationally utilized and combined with AuNPs and cationic polymer polydiallyl dimethyl ammonium chloride(PDDA)for the development of the label-free colorimetric aptasensor,in which the 3’terminal was thoroughly exposed to OA.The aptasensor provided robust performance with a linear detection range of 100-1200 nmol L-1,a limit of detection of 41.30 nmol L-1,recovery rates of 91.6%-106.2%,as well as a high selectivity towards OA in shellfish samples.The whole detection process can be completed within 1 h.To our best knowledge,this is the first time that the anti-OA aptamer was thoroughly studied,and a label-free colorimetric aptasensor was rationally designed in this way.This study not only provides a rapid detection method for highly sensitive and specific detection of OA,but also serves as a reference for the design of efficient aptasensors in the future.
文摘Lymphomas are cancers that arise from white blood cells and usually present as solid tumors. Treatment of lymphoma often involves chemotherapy, and can also include radiotherapy and/or bone marrow transplantation. There is an unquestioned need for more effective therapies and diagnostic tool for lymphoma. Aptamers are single stranded DNA or RNA oligonucleotides whose three-dimensional structures are dictated by their sequences. The immense diversity in function and structure of nucleic acids enable numerous aptamers to be generated through an iterative in vitro selection technique known as Systematic Evolution of Ligands by EXponential enrichment (SELEX). Aptamers have several biochemical properties that make them attractive tools for use as potential diagnostic and pharmacologic agents. Isolated aptamers may directly inhibit the function of target proteins, or they can also be formulated for use as delivery agents for other therapeutic or imaging cargoes. More complex aptamer identification methods, using whole cancer cells (Cell-SELEX), may identify novel targets and aptamers to affect them. This review focuses on recent advances in the use of nucleic acid aptamers as diagnostic and therapeutic agents and as targeted delivery carriers that are relevant to lymphoma. Some representative examples are also discussed.
基金funded by grants from the Alberta Prion Research Institutethe Alzheimer Society of Alberta and Northwest Territories+2 种基金the Natural Sciences and Engineering Research Council(NSERC)of Canadasupported by the Canada Research Chair programa postdoctoral fellowship from the German Research Foundation(DFG)
文摘Despite intensive research,most neurodegenerative diseases cannot be cured and for some of them no treatment is available to increase survival or quality of life.Among the latter are prion diseases,fatal and transmissible neurodegenerative diseases of humans and other animals.Exam-
文摘Ochratoxin A(OTA),one of the most dangerous mycotoxins for human health,has been subjected to numerous studies for separation and detection in minimal amounts.Aptamers as novel recognition elements have been employed to fabricate ultrasensitive biosensors for the detection of OTA and designing delicate analytical tools.This review attempted to comprehensively examine all reported aptamer-based detection and separation platforms for ochratoxin.The most relevant databases were considered to discover all specific aptamers for dealing with OTA.Aptamer-based detection and separation devices specified for OTA were searched for,analyzed,discussed,and classified based on their specifications.The optical aptasensors have gathered a higher interest than electrochemical aptasensors,which can achieve a lower limit of detections.Moreover,some extraction platforms based on these aptamers were also found.However,aptamer-based devices seem to have some challenges in their application.
文摘Background: Nine proteins were identified as putative profibrotic biomarkers in systemic sclerosis (SSc) and an unrelated fibrotic disease in a previously published proteomic study. As the majority of these proteins were orphans of commercially available antibodies, the nine proteins were investigated to determine whether binding peptide aptamers of the Stefin A quadruple mutant-Tracy variant (referred to as “affimers”) could be validated by enzyme linked immunosorbant assay (ELISA) to allow the quantification of these candidate biomarkers in the sera of SSc patients. Materials and Methods: Candidate biomarker peptides were analysed by high throughput affimer microarray to identify binding affimers. Two candidate biomarkers were prioritised, and binding affimers were expressed from genetically modified BL21 competent E. coli strains and purified. These affimers were used in indirect ELISA, and then sandwich ELISA formats against the candidate biomarker recombinant proteins osteonectin and pigment epi-thetlium-derived factor (PEDF). Results: 39 affimers were identified as binders for eight of the nine candidate biomarker peptides were by affimer microarray;six for osteonectin and eleven for PEDF. Two of the six and all eleven were able to recognize physiological concentrations (5 and 1 μg·ml﹣1) of osteonectin and PEDF, respectively by indirect ELISA. In sandwich ELISA format: two affimers were able to detect recombinant PEDF;however, the two affimers identified in indirect ELISA were unable to recognise recombinant osteonectin, and were thus hypothesised to bind to osteonectin at the same binding site. Discussion: SSc is currently an orphan of fully validated biomarkers, which is required for the development of stratified medicine in this field. This approach has laid the groundwork for an affimer based on multiplexed assay, to validate biomarkers in the sera of SSc patients in the future.
基金Supported by the National Key Scientific Instrument and Equipment Development Projects of China(2012YQ04014005)。
文摘Acute myocardial infarction(AMI)is a major health problem leading to high rates of mortality and morbidity.Biomarker cardiac troponin I(cTnI)has shown high sensitivity and specificity towards AMI detection,and has been regarded as"gold standard".An ultrasensitive method to detectcTnI with low concentration in human fluid is essential.In this paper,we developed an aptamer-based assay coupled with rolling circle amplification(RCA)and molecular beacon probe for sensitive detection ofcTnI.In this strategy,aptamer acts as a bridge to communicate between oligonucleotides andcTnI.RCA reaction produces a single-stranded tandem repeated copy of the circular template,which are recognized by fluorescence molecular beacon probe.With this strategy,highly sensitive and specific detection of cTnI was realized with the lowest detectable concentration of 7.24 pg/m L.The developed aptamer-RCA assay can be a promising tool in clinical samples analysis.The assay can also analyze other disease-related biomarkers by replacing the aptamer.
基金supported by an Exploratory Research Grant Scheme(ERGS203/CIPPM/6730106)+2 种基金Higher Institution Centre of Excellent(HICo E311/CIPPM/4401005)from the Malaysian,Ministry of Higher EducationUniversiti Sains Malaysia Fellowship Scheme.
文摘Objective:To isolate and characterize RNA aptamers that are specific to human CD36 protein using systematic evolution of ligands by exponential enrichment(SELEX)technology to identify candidates for adjunct therapy to reverse the binding of Plasmodiuminfected erythrocytes.Methods:RNA aptamers were isolated using nitrocellulose membrane-based SELEX and binding analysis was screened using an electrophoretic mobility shift assay and enzyme-linked oligonucleotide assay.Results:Thirteen cycles of nitrocellulose membrane-based SELEX yielded three aptamers(RC60,RC25,RC04)exhibiting high binding against CD36 protein as shown on electrophoretic mobility shift assay.The sequence analysis revealed a G-quadruplex sequence within all the isolated aptamers that might contribute to aptamer binding and thermodynamic stability.The specificity assay further showed that RC60 and RC25 were highly specific to CD36.The competitive inhibition assay demonstrated that RC60 and RC25 shared a similar binding epitope recognized by m Ab FA6-152,a specific monoclonal antibody against CD36.Conclusions:RC60 and RC25 are promising candidates as anticytoadherence for severe malaria adjunct therapy.
基金National Natural Science Foundation of China (No.81700836,No.81470629,No.81670860)Chongqing Natural Research Foundation (No.cstc 2018jcyj AX0034)。
文摘AIM:To confirm whether exosome-mediated delivery of aptamer S58(Exo-S58) has a better antifibrotic effect than naked S58 in human conjunctival fibroblasts(HCon Fs) and a rat glaucoma filtration surgery(GFS) model.METHODS:To enhance the effective reaction time of aptamer S58 in vivo, we loaded aptamer S58 into exosomes derived from HEK293 T cells by PEI transfection to determine the effect of Exo-S58 in HCon Fs and a rat GFS model.RESULTS:Exo-S58 can significantly reduce cell proliferation, migration and fibrosis in TGF-β2-induced HCon Fs. In an in vivo experiment, Exo-S58 treatment prolonged filtering bleb retention and reduced fibrosis compared with naked S58 treatment in GFS rats.CONCLUSION:The exosomes are safe and valid carriers to deliver aptamers. Furthermore, Exo-S58 exhibited superior antifibrotic effect than naked S58 both in HCon Fs cells and rat GFS models.
