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1.
Angew Chem Int Ed Engl ; 60(45): 24266-24274, 2021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34464491

RESUMO

We report a simple and rapid saliva-based SARS-CoV-2 antigen test that utilizes a newly developed dimeric DNA aptamer, denoted as DSA1N5, that specifically recognizes the spike proteins of the wildtype virus and its Alpha and Delta variants with dissociation constants of 120, 290 and 480 pM, respectively, and binds pseudotyped lentiviruses expressing the wildtype and alpha trimeric spike proteins with affinity constants of 2.1 pM and 2.3 pM, respectively. To develop a highly sensitive test, DSA1N5 was immobilized onto gold electrodes to produce an electrochemical impedance sensor, which was capable of detecting 1000 viral particles per mL in 1:1 diluted saliva in under 10 min without any further sample processing. Evaluation of 36 positive and 37 negative patient saliva samples produced a clinical sensitivity of 80.5 % and specificity of 100 % and the sensor could detect the wildtype virus as well as the Alpha and Delta variants in the patient samples, which is the first reported rapid test that can detect any emerging variant of SARS-CoV-2.


Assuntos
Antígenos Virais/análise , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais , Teste Sorológico para COVID-19 , Técnicas Eletroquímicas , SARS-CoV-2/genética , Humanos , Saliva/química
2.
Nucleic Acids Res ; 49(13): 7267-7279, 2021 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-34232998

RESUMO

We performed in vitro selection experiments to identify DNA aptamers for the S1 subunit of the SARS-CoV-2 spike protein (S1 protein). Using a pool of pre-structured random DNA sequences, we obtained over 100 candidate aptamers after 13 cycles of enrichment under progressively more stringent selection pressure. The top 10 sequences all exhibited strong binding to the S1 protein. Two aptamers, named MSA1 (Kd = 1.8 nM) and MSA5 (Kd = 2.7 nM), were assessed for binding to the heat-treated S1 protein, untreated S1 protein spiked into 50% human saliva and the trimeric spike protein of both the wildtype and the B.1.1.7 variant, demonstrating comparable affinities in all cases. MSA1 and MSA5 also recognized the pseudotyped lentivirus of SARS-CoV-2 with respective Kd values of 22.7 pM and 11.8 pM. Secondary structure prediction and sequence truncation experiments revealed that both MSA1 and MSA5 adopted a hairpin structure, which was the motif pre-designed into the original library. A colorimetric sandwich assay was developed using MSA1 as both the recognition element and detection element, which was capable of detecting the pseudotyped lentivirus in 50% saliva with a limit of detection of 400 fM, confirming the potential of these aptamers as diagnostic tools for COVID-19 detection.


Assuntos
Aptâmeros de Nucleotídeos , COVID-19/virologia , Biblioteca Gênica , Mutação , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/genética , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/genética , Pareamento de Bases , Sequência de Bases , COVID-19/diagnóstico , Colorimetria/métodos , Humanos , Conformação de Ácido Nucleico , Técnica de Seleção de Aptâmeros
3.
Anal Bioanal Chem ; 413(18): 4635-4644, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33735408

RESUMO

Pd-Ir nanocubes are promising peroxidase-mimicking nanozymes for immunoassays, enabled by their excellent stability, relatively high catalytic activity, and reproducible performance. A key step involved in the preparation of Pd-Ir nanocubes is the synthesis of Pd nanocubes. However, the traditional method to synthesize Pd nanocubes requires sophisticated and expensive equipment to precisely control the reaction temperature and highly skilled technicians to achieve satisfactory and reproducible product yields. Herein, we report a simple, cost-effective, high-yield (> 99%) and one-pot strategy to synthesize Pd nanocubes with sizes of 7, 18, and 51 nm for the preparation of Pd-Ir nanocubes. The resulting 18 nm Pd-Ir nanocubes display three orders of magnitude higher peroxidase activity compared to horseradish peroxidase, leading to a significantly increased detection sensitivity when applied in the immunoassay of nucleocapsid protein from SARS-CoV-2. Due to the simplicity in both material synthesis and assaying procedures and the excellent detection sensitivity, our method should allow for the generalized application of Pd-Ir nanocube-based immunoassays for the diagnosis of human diseases.


Assuntos
COVID-19/diagnóstico , Proteínas do Nucleocapsídeo de Coronavírus/química , Imunoensaio/métodos , Irídio/química , Paládio/química , SARS-CoV-2 , Anticorpos Antivirais , Análise Custo-Benefício , Humanos , Imunoensaio/economia , Estrutura Molecular , Nanoestruturas/química , Nanoestruturas/economia , Fosfoproteínas/química
4.
ACS Appl Mater Interfaces ; 13(8): 9464-9471, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33410654

RESUMO

Molecular recognition elements with high specificity are of great importance for the study of molecular interactions, accurate diagnostics, drug design, and personalized medicine. Herein, a highly specific DNA aptamer for RNase H2 from Clostridium difficile (C. difficile) was generated by SELEX and minimized to 40 nucleotides. The aptamer exhibits a dissociation constant (Kd) of 1.8 ± 0.5 nM and an inhibition constant (IC50) of 7.1 ± 0.6 nM for C. difficile RNase H2, both of which are 2 orders of magnitude better for the same enzyme from other control bacteria. The fluorescent version of the aptamer can distinguish C. difficile from several other control bacteria in a cell lysate assay. This work demonstrates that a ubiquitous protein like RNase H2 can still be used as the target for the development of highly specific aptamers and the combination of the protein and the aptamer can achieve the recognition specificity needed for a diagnostic test and drug development.


Assuntos
Aptâmeros de Nucleotídeos/química , Proteínas de Bactérias/análise , Clostridioides difficile/enzimologia , DNA/química , Ribonucleases/análise , Aptâmeros de Nucleotídeos/metabolismo , Proteínas de Bactérias/metabolismo , Biomarcadores/análise , Biomarcadores/metabolismo , DNA/metabolismo , Fluoresceínas/química , Corantes Fluorescentes/química , Ligação Proteica , Ribonucleases/metabolismo , Técnica de Seleção de Aptâmeros
5.
Chembiochem ; 21(11): 1547-1566, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32176816

RESUMO

Circular nucleic acids (CNAs) are nucleic acid molecules with a closed-loop structure. This feature comes with a number of advantages including complete resistance to exonuclease degradation, much better thermodynamic stability, and the capability of being replicated by a DNA polymerase in a rolling circle manner. Circular functional nucleic acids, CNAs containing at least a ribozyme/DNAzyme or a DNA/RNA aptamer, not only inherit the advantages of CNAs but also offer some unique application opportunities, such as the design of topology-controlled or enabled molecular devices. This article will begin by summarizing the discovery, biogenesis, and applications of naturally occurring CNAs, followed by discussing the methods for constructing artificial CNAs. The exploitation of circular functional nucleic acids for applications in nanodevice engineering, biosensing, and drug delivery will be reviewed next. Finally, the efforts to couple functional nucleic acids with rolling circle amplification for ultra-sensitive biosensing and for synthesizing multivalent molecular scaffolds for unique applications in biosensing and drug delivery will be recapitulated.


Assuntos
Técnicas Biossensoriais/métodos , DNA Catalítico/genética , DNA Circular/genética , Engenharia Genética/métodos , RNA Catalítico/genética , RNA Circular/genética , Animais , Aptâmeros de Nucleotídeos/síntese química , Aptâmeros de Nucleotídeos/genética , Aptâmeros de Nucleotídeos/metabolismo , DNA Catalítico/química , DNA Catalítico/metabolismo , DNA Circular/química , DNA Circular/metabolismo , Sistemas de Liberação de Medicamentos/métodos , Humanos , Nanotecnologia , Técnicas de Amplificação de Ácido Nucleico , Conformação de Ácido Nucleico , Estabilidade de RNA , RNA Catalítico/química , RNA Catalítico/metabolismo , RNA Circular/química , RNA Circular/metabolismo
6.
J Mater Chem B ; 8(16): 3213-3230, 2020 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-31942914

RESUMO

Recently, portable sensing devices with point of care testing (POCT) capability have attracted great attention due to their inherent affordability and accessibility in low resource areas. Paper sensors possess excellent potential as POCT platforms because of low cost, ease of operation, disposability and high-volume manufacturing. Paper sensors that incorporate functional nucleic acids (FNAs) as recognition elements are particularly attractive given that FNAs can be isolated from random-sequence nucleic acid pools to recognize, or respond to, virtually any target of interest. In this review, the advantages of FNAs, particularly DNA aptamers and DNAzymes, as recognition elements for the design of paper sensors are first discussed. This is followed by reviewing three specific types of FNA based paper sensors: dot blots, lateral flow assays, and microfluidic paper-based analytical devices. Furthermore, advances in the signal reporting methods used by FNA based paper sensors are summarized. Finally, limitations of current FNA based paper sensors are discussed along with considerations of future research directions.


Assuntos
Técnicas Biossensoriais , Ácidos Nucleicos/análise , Papel , Testes Imediatos , Humanos , Tamanho da Partícula , Propriedades de Superfície
7.
Chemistry ; 26(3): 592-596, 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31475757

RESUMO

DNA detection is usually conducted under nondenaturing conditions to favor the formation of Watson-Crick base-paring interactions. However, although such a setting is excellent for distinguishing a single-nucleotide polymorphism (SNP) within short DNA sequences (15-25 nucleotides), it does not offer a good solution to SNP detection within much longer sequences. Here we report on a new detection method capable of detecting SNP in a DNA sequence containing 35-90 nucleotides. This is achieved through incorporating into the recognition DNA sequence a previously discovered DNA molecule that forms a stable G-quadruplex in the presence of 7 molar urea, a known condition for denaturing DNA structures. The systems are configured to produce both colorimetric and fluorescent signals upon target binding.


Assuntos
DNA/química , Desnaturação de Ácido Nucleico/genética , Polimorfismo de Nucleotídeo Único/genética , Colorimetria , DNA/genética , Quadruplex G , Conformação de Ácido Nucleico
8.
Chemistry ; 26(3): 568, 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31696988

RESUMO

Invited for the cover of this issue is the group of Yingfu Li at McMaster University. The image depicts a molecular switch for ultra-specific detection of DNA utilizing a guanine-quadruplex (up-right structure) resistant to denaturation by urea (ball-and-stick structures). Read the full text of the article at 10.1002/chem.201903536.


Assuntos
DNA/genética , Guanina/química , Lítio/química , Polimorfismo de Nucleotídeo Único/genética , DNA/química , Guanina/análise
9.
ACS Appl Mater Interfaces ; 10(16): 13390-13396, 2018 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-29582655

RESUMO

Pressure-based bioassays (PASS) integrate a molecular recognition process with a catalyzed gas generation reaction, enabling sensitive and portable quantitation of biomarkers in clinical samples. Using platinum nanoparticles (PtNPs) as a catalyst has significantly improved the sensitivity of PASS compared with protein enzyme-based detection. However, PtNPs are easily deactivated during storage or after being decorated with antibodies. Moreover, nonspecific adsorption of PtNPs on substrates has been a problem, resulting in significant backgrounds. To solve these problems of PtNP-based detection, we report a robust, simple, stable, and sensitive Pt staining method for PASS. Detection antibody-decorated gold nanoparticles (AuNPs) are used to perform enzyme-linked immunosorbent assay, followed by Pt staining to stain AuNPs with Ag and Pt bimetallic shells (Au@AgPtNPs), which endow AuNPs with catalytic activity. The concentration of targets can be quantitatively determined by measuring the pressure due to O2 gas (g) formed by the decomposition of H2O2 catalyzed by Au@AgPtNPs. C-reactive protein and avian influenza hemagglutinin 5 neuraminidase 1 can be quantitatively detected with detection limits of 0.015 and 0.065 ng/mL, respectively. The simple, stable, and sensitive properties of the Pt staining-based method will largely broaden the applications of PASS in clinical diagnosis and biomedicine.


Assuntos
Bioensaio , Ouro , Peróxido de Hidrogênio , Nanopartículas Metálicas , Platina , Coloração e Rotulagem
10.
Chem Commun (Camb) ; 53(65): 9055-9058, 2017 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-28707690

RESUMO

A non-enzyme cascade amplification strategy, based on the dissolution of Ag nanoparticles and a Pt nanocube-catalyzed reaction, for colorimetric assay of disease biomarkers was developed. This strategy overcomes the intrinsic limitations of enzymes involved in conventional enzymatic amplification techniques, thanks to the utilization of noble-metal nanostructures with superior properties.


Assuntos
Biomarcadores/análise , Imunoensaio/métodos , Nanopartículas Metálicas/química , Platina/química , Prata/química , Animais , Benzidinas/química , Catálise , Compostos Cromogênicos/química , Colorimetria/métodos , Cabras , Humanos , Peróxido de Hidrogênio/química , Imunoglobulina G/imunologia , Calicreínas/análise , Calicreínas/imunologia , Limite de Detecção , Oxirredução , Tamanho da Partícula , Antígeno Prostático Específico/análise , Antígeno Prostático Específico/imunologia , Coelhos
11.
ACS Appl Mater Interfaces ; 9(27): 22252-22258, 2017 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-28650611

RESUMO

Point-of-care testing (POCT) with the advantages of speed, simplicity, and low cost, as well as no need for instrumentation, is critical for the measurement of analytes in a variety of environments lacking access to laboratory infrastructure. In the present study, a hydrogel pressure-based assay for quantitative POCT was developed by integrating a target-responsive hydrogel with pressuremeter readout. The target-responsive hydrogels were constructed with DNA grafted linear polyacrylamide and the cross-linking DNA for selective target recognition. The hydrogel response to the target substance allows release of the preloaded Pt nanoparticles, which have good stability and excellent catalytic ability for decomposing H2O2 to O2. Then, the generated O2 in a sealed environment leads to significant pressure increase, which can be easily read out by a handheld pressuremeter. Using this target-responsive hydrogel pressure-based assay, portable and highly sensitive detection of cocaine, ochratoxin A, and lead ion were achieved with excellent accuracy and selectivity. With the advantages of portability, high sensitivity, and simple sample processing, the hydrogel pressure-based assay shows great potential for quantitative POCT of a broad range of targets in resource-limited settings.


Assuntos
Hidrogéis/química , Cocaína , Hidrogel de Polietilenoglicol-Dimetacrilato , Peróxido de Hidrogênio , Testes Imediatos
12.
Chem Commun (Camb) ; 53(47): 6375-6378, 2017 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-28555677

RESUMO

A new method based on a functional DNA crosslinked hydrogel as a target-responsive unit and gold nanorods (AuNRs) as a multicolor signal readout circuit was developed for the sensitive and visual detection of different targets. The color variation of the AuNR solution was correlated with the concentration of the target. This system can be extended to detect various targets by designing the corresponding target-responsive DNA hydrogels.


Assuntos
Colorimetria/métodos , DNA/química , Ouro/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Nanotubos/química
13.
Small ; 12(39): 5449-5487, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27551864

RESUMO

It is demonstrated that DNA can be used to control the synthesis of silver nanoplates with different morphologies using spherical silver seeds. UV-vis spectroscopy, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy are used to characterize the synthesized nanoparticles. Silver nanoprisms are encoded by poly C and poly G, while silver flower bouquets and silver nanodiscs are synthesized using poly A and poly T, respectively. The length of DNA is found to have little effect on the morphology of silver nanoparticles. Moreover, the synthesized silver nanoplates are found to have high surface enhanced Raman scattering enhancement ability, good antibacterial activity, and good biocompatibility. These discoveries will broaden the application of DNA in nanoscience and will provide a new platform to investigate the interaction between DNA sequences and silver nanoparticles.


Assuntos
DNA/química , Nanopartículas Metálicas/química , Prata/química , Sequência de Bases , Células HeLa , Humanos , Cinética , Nanopartículas Metálicas/ultraestrutura , Espectroscopia Fotoeletrônica , Espectrofotometria Ultravioleta
14.
Anal Chem ; 88(15): 7828-36, 2016 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-27385563

RESUMO

Due to its large enhancement effect, nanostructure-based surface-enhanced Raman scattering (SERS) technology had been widely applied for bioanalysis and cell imaging. However, most SERS nanostructures suffer from poor signal reproducibility, which hinders the application of SERS nanostructures in quantitative detection. We report an etching-assisted approach to synthesize SERS-active plasmonic nanoparticles with 1 nm interior nanogap for multiplex quantitative detection and cancer cell imaging. Raman dyes and methoxy poly(ethylene glycol) thiol (mPEG-SH) were attached to gold nanoparticles (AuNPs) to prepare gold cores. Next, Ag atoms were deposited on gold cores in the presence of Pluronic F127 to form a Ag shell. HAuCl4 was used to etch the Ag shell and form an interior nanogap in Au@AgAuNPs, leading to increased Raman intensity of dyes. SERS intensity distribution of Au@AgAuNPs was found to be more uniform than that of aggregated AuNPs. Finally, Au@AgAuNPs were used for multiplex quantitative detection and cancer cell imaging. With the advantages of simple and rapid preparation of Au@AgAuNPs with highly uniform, stable, and reproducible Raman intensity, the method reported here will widen the applications of SERS-active nanoparticles in diagnostics and imaging.


Assuntos
Nanopartículas Metálicas/química , Nanoestruturas/química , Análise Espectral Raman , Proteína C-Reativa/análise , Linhagem Celular Tumoral , Cloretos/química , Ensaio de Imunoadsorção Enzimática , Violeta Genciana/química , Ouro/química , Compostos de Ouro/química , Humanos , Limite de Detecção , Microscopia de Fluorescência , Polietilenoglicóis/química , Prata/química , Compostos de Sulfidrila/química
15.
Chem Commun (Camb) ; 52(54): 8452-4, 2016 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-27306114

RESUMO

A portable method for the rapid detection of the disease biomarker C-reactive protein (CRP) with a hand-held pressuremeter was developed. The method allows an ultrasensitive quantitation of CRP within the entire clinical range. The pressure-based method could facilitate CRP measurements in point-of-care testing (POCT) scenarios, such as clinical offices, emergency departments, and community service centers.


Assuntos
Bioensaio/instrumentação , Proteína C-Reativa/análise , Testes Imediatos , Pressão , Limite de Detecção , Fatores de Tempo
16.
Lab Chip ; 16(7): 1139-51, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-26928571

RESUMO

Equipment-free devices with quantitative readout are of great significance to point-of-care testing (POCT), which provides real-time readout to users and is especially important in low-resource settings. Among various equipment-free approaches, distance-based visual quantitative detection methods rely on reading the visual signal length for corresponding target concentrations, thus eliminating the need for sophisticated instruments. The distance-based methods are low-cost, user-friendly and can be integrated into portable analytical devices. Moreover, such methods enable quantitative detection of various targets by the naked eye. In this review, we first introduce the concept and history of distance-based visual quantitative detection methods. Then, we summarize the main methods for translation of molecular signals to distance-based readout and discuss different microfluidic platforms (glass, PDMS, paper and thread) in terms of applications in biomedical diagnostics, food safety monitoring, and environmental analysis. Finally, the potential and future perspectives are discussed.


Assuntos
Técnicas Analíticas Microfluídicas/métodos , Testes Imediatos , Humanos
17.
Biosens Bioelectron ; 80: 1-8, 2016 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-26802746

RESUMO

Gliosarcoma, a variant of glioblastoma multiforme (GBM), is a highly invasive malignant tumor. Unfortunately, this disease still marked by poor prognosis regardless of modern treatments. It is of great significance to discover specific molecular probes targeting gliosarcoma for early cancer diagnosis and therapy. Herein, we have selected a group of DNA aptamers with high affinity and selectivity against gliosarcoma cells K308 using cell-SELEX. All the dissociation constants of these aptamers against gliosarcoma cells were in the nanomolar range and aptamer WQY-9 has the highest affinity and good selectivity among them. Furthermore, truncated aptamer sequence, WQY-9-B, shows similar recognition ability to aptamer WQY-9. In addition, WQY-9-B was found to be able to bind selectively and internalize into cytoplasm of target cancer cell at 37 °C. More importantly, compared to a random sequence, aptamer WQY-9-B showed excellent recognition rate (73.3%) for tissue sections of clinical gliosarcoma samples. These data suggests that aptamer WQY-9-B has excellent potential as an effective molecular probe for gliosarcoma diagnosis.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Glioblastoma/diagnóstico por imagem , Gliossarcoma/diagnóstico por imagem , Linhagem Celular Tumoral , Detecção Precoce de Câncer , Glioblastoma/patologia , Gliossarcoma/patologia , Humanos , Sondas Moleculares , Técnica de Seleção de Aptâmeros/métodos
18.
Biosens Bioelectron ; 77: 537-42, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26474094

RESUMO

Paper based microfluidics (µPADs) with advantages of portability, low cost, and ease of use have attracted extensive attention. Here we describe a novel method that integrates glucoamylase-trapped aptamer-crosslinked hydrogel for molecular recognition with cascaded enzymatic reactions for signal amplification and a µPAD for portable readout. Upon target introduction, the hydrogel decomposes to release glucoamylase, which catalyzes the hydrolysis of amylose to produce a large amount of glucose. With a simple folding of the µPAD, the sample solution containing glucose product wicks and diffuses in parallel to each test-zone to carry out homogeneous assays, where glucose is used to produce I2 for brown color visualization through multiple enzymatic and chemical cascade reactions. Through color gradient changes based on different concentrations of the target, a semiquantitative assay is achieved by the naked eye, and quantitation can be obtained by handheld devices. Detection of cocaine in buffer and urine was performed to demonstrate the utility of the hydrogel-µPAD system. More importantly, the hydrogel-µPAD system can be extended to the detection of various targets by incorporating the corresponding aptamer into the hydrogel. The hydrogel-µPAD system reported here provides a new platform for portable, disposable and visual detection of a wide range of targets.


Assuntos
Cocaína/sangue , Cocaína/urina , Glucana 1,4-alfa-Glucosidase/química , Dispositivos Lab-On-A-Chip , Papel , Sistemas Automatizados de Assistência Junto ao Leito , Colorimetria/instrumentação , Equipamentos Descartáveis , Desenho de Equipamento , Análise de Falha de Equipamento , Hidrogéis/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Detecção do Abuso de Substâncias/instrumentação
19.
Angew Chem Int Ed Engl ; 54(36): 10448-53, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26180027

RESUMO

Herein, we demonstrate that a very familiar, yet underutilized, physical parameter­gas pressure­can serve as signal readout for highly sensitive bioanalysis. Integration of a catalyzed gas-generation reaction with a molecular recognition component leads to significant pressure changes, which can be measured with high sensitivity using a low-cost and portable pressure meter. This new signaling strategy opens up a new way for simple, portable, yet highly sensitive biomedical analysis in a variety of settings.


Assuntos
Pressão , Técnicas Biossensoriais , Ensaio de Imunoadsorção Enzimática , Limite de Detecção
20.
Langmuir ; 31(28): 7869-76, 2015 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-26101941

RESUMO

DNA conjugated gold nanorods (AuNRs) are widely applied for nanostructure assembly, gene therapy, biosensing, and drug delivery. However, it is still a great challenge to attach thiolated DNA on AuNRs, because the positively charged AuNRs readily aggregate in the presence of negatively charged DNA. This article reports an mPEG-SH/Tween 20-assisted method to load thiolated DNA on AuNRs in 1 h. Tween 20 and mPEG-SH are used to synergistically displace CTAB on the surface of AuNRs by repeated centrifugation and resuspension, and thiolated DNA are attached to AuNRs in the presence of 1 M NaCl, 100 mM MgCl2, or 100 mM citrate. AuNRs with different sizes and aspect ratios can be functionalized with DNA by this method. The number of DNA loaded on each AuNR can be easily controlled by the concentrations of mPEG-SH and Tween 20 or the ratio between DNA and AuNR. Functionalized AuNRs were used for nanoparticle assembly and cancer cell imaging to confirm that DNA anchored on the surface of AuNRs retains its hybridization and molecular recognition capability. The new method is easy, rapid, and robust for the preparation of DNA functionalized AuNRs for a variety of applications such as cancer therapy, drug delivery, self-assembly, and imaging.


Assuntos
Ouro/química , Nanotecnologia/métodos , Nanotubos/química , Oligonucleotídeos/química , Polietilenoglicóis/química , Polissorbatos/química , Compostos de Sulfidrila/química , Sequência de Bases , DNA/química , DNA/genética , Ligantes , Modelos Moleculares , Conformação Molecular , Oligonucleotídeos/genética , Fatores de Tempo
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