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1.
Top Curr Chem (Cham) ; 378(2): 26, 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32067108

RESUMO

Genetic information and the blueprint of life are stored in the form of nucleic acids. The primary sequence of DNA, read from the canonical double helix, provides the code for RNA and protein synthesis. Yet these already-information-rich molecules have higher-order structures which play critical roles in transcription and translation. Uncovering the sequences, parameters, and conditions which govern the formation of these structural motifs has allowed researchers to study them and to utilize them in biotechnological and therapeutic applications in vitro and in vivo. This review covers both DNA and RNA structural motifs found naturally in biological systems including catalytic nucleic acids, non-coding RNA, aptamers, G-quadruplexes, i-motifs, and Holliday junctions. For each category, an overview of the structural characteristics, biological prevalence, and function will be discussed. The biotechnological and therapeutic applications of these structural motifs are highlighted. Future perspectives focus on the addition of proteins and unnatural modifications to enhance structural stability for greater applicability.


Assuntos
Biotecnologia , Ácidos Nucleicos/química , Ácidos Nucleicos/uso terapêutico , Conformação de Ácido Nucleico
2.
Chem Commun (Camb) ; 56(4): 647-650, 2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31840153

RESUMO

Here, we demonstrate use of a Mg2+-dependent, site-specific DNA enzyme (DNAzyme) to cleave oligos from polyacrylamide gel beads, which is suitable for use in drop-based assays. We show that cleavage efficiency is improved by use of a tandem-repeat cleavage site. We further demonstrate that DNAzyme-released oligos function as primers in reverse transcription of cell-released mRNA.


Assuntos
DNA Catalítico/metabolismo , Ácidos Nucleicos/metabolismo , Resinas Acrílicas/química , Resinas Acrílicas/metabolismo , Géis/química , Géis/metabolismo , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/metabolismo , Magnésio/química , Magnésio/metabolismo , Técnicas de Amplificação de Ácido Nucleico , Ácidos Nucleicos/química , Tamanho da Partícula , Propriedades de Superfície
3.
Soft Matter ; 16(3): 634-641, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31840704

RESUMO

Several analytical calculations and computer simulations propose that cylindrical monodispersive rods having an aspect ratio (ratio of length to diameter) greater than 4 can exhibit liquid crystal (LC) ordering. But, recent experiments demonstrated the signature of LC ordering in systems of 4- to 20-base pair (bp) long nucleic acids (NAs) that do not satisfy the shape anisotropy criterion. Mechanisms of end-to-end adhesion and stacking have been proposed to explain this phenomenon. In this study, using all-atom molecular dynamics (MD) simulation, we explicitly verify the end-to-end stacking of double-stranded RNA (dsRNA) and demonstrate the LC ordering at the microscopic level. Using umbrella sampling (US) calculation, we quantify the potential of mean force (PMF) between two dsRNAs for various reaction coordinates (RCs) and compare our results with previously reported PMFs for double-stranded DNA (dsDNA). The PMF profiles demonstrate the anisotropic nature of inter-NA interaction. We find that, like dsDNA, dsRNA also prefers to stack on top of each other while repelling sideways, leading to the formation of supra-molecular-columns that undergo LC ordering at high NA volume fraction (φ). We also demonstrate and quantify the nematic ordering of the RNAs using several hundred nanosecond-long MD simulations that remain almost invariant for different initial configurations and under different external physiological conditions.


Assuntos
Cristais Líquidos/química , Simulação de Dinâmica Molecular , Ácidos Nucleicos/química , Anisotropia , Conformação de Ácido Nucleico , Termodinâmica
4.
Mikrochim Acta ; 186(12): 824, 2019 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-31754805

RESUMO

The authors describe a tetrahedral DNA nanostructure loaded with SYBR Green (SG-TDN) for fluorometric determination of nucleic acids. After intercalating into the TDN, fluorescence of SG is enhanced by 260-fold (exc 480 nm, em 524 nm), and the resulting SG-TDN nanoflare displays >7-fold stronger fluorescence than that of FAM-labeled TDN. The SG-TDNs were coupled to magnetic microparticles and polydopamine nanoparticles to construct multi-functional nanoprobes through sequence hybridization using a toehold strand. The method was applied to detect a stretch of microRNA sequence (20 bp) in buffer and in undiluted serum with excellent selectivity, over a wide linear range and with a low limit of detection (0.2 nM). The probe was also applied for visualization of tumor-related microRNA in living cells via fluorescence imaging. Graphical abstract Schematic representation of tetrahedron-based DNA nanoflare for fluorometric nucleic acid determination in undiluted blood serum and living cells.


Assuntos
Corantes Fluorescentes/química , Substâncias Intercalantes/química , Nanoestruturas/química , Ácidos Nucleicos/química , Células A549 , Técnicas Biossensoriais , DNA/química , Fluorometria , Células HEK293 , Humanos , Indóis , Limite de Detecção , MicroRNAs/química , Hibridização de Ácido Nucleico , Imagem Óptica , Polímeros , Sensibilidade e Especificidade
5.
Environ Monit Assess ; 191(12): 732, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31705223

RESUMO

Isolation and purification of nucleic acids are basic laboratory procedures used in molecular analysis supporting determination of organisms in environmental monitoring. However, many different methods of isolation are commonly used, often being designed for a particular type of DNA extraction. While researchers commonly decide on commercial isolation kits for their ease of use and efficiency, they require large amounts of studied tissue, and the cost of purchasing such kits over a long run can be high. To provide an alternative to using commercial kits, we have developed a simple, rapid, cost-effective, and reliable protocol for DNA isolation from cultured fungi on slants and from dried fungal samples using silica particles (silicon dioxide powder) in chaotropic conditions. With the presented method, it is possible to isolate good-quality DNA from fungi in less than 1.5 h, using easily accessible chemicals. Compared with other methods employing CTAB or commercial kits, it allows fast, easy, and cheap DNA purification from two main sources of fungi routinely used for research. In addition to the method protocol, we also provide advice for further optimization of the isolation process to account for specific conditions, making the procedure more useful.


Assuntos
Monitoramento Ambiental/métodos , Ácidos Nucleicos/química , Dióxido de Silício/química , DNA , Fungos/genética
6.
Chem Commun (Camb) ; 55(91): 13733-13736, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31661100

RESUMO

The tough challenges for the convenient and quantitative determination of circulating miRNAs (cmiRNAs) in the peripheral blood are low abundance, high interference and lack of direct digital readout. Here, we developed dual-enhanced magnetobiosensors based on cascaded nucleic acid circuits, which integrate catalyzed hairpin assembly (CHA) with the hybridization chain reaction (HCR), for sensitive, portable and digital quantitative detection of circulating miRNAs in serum by a personal glucose meter (PGM).


Assuntos
Técnicas Biossensoriais/métodos , Campos Magnéticos , MicroRNAs/sangue , Ácidos Nucleicos/química , Glucose/química , Humanos , Hibridização de Ácido Nucleico
7.
Nat Commun ; 10(1): 4918, 2019 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-31664022

RESUMO

Nanopore sensing is a powerful single-molecule approach for the detection of biomolecules. Recent studies have demonstrated that aerolysin is a promising candidate to improve the accuracy of DNA sequencing and to develop novel single-molecule proteomic strategies. However, the structure-function relationship between the aerolysin nanopore and its molecular sensing properties remains insufficiently explored. Herein, a set of mutated pores were rationally designed and evaluated in silico by molecular simulations and in vitro by single-channel recording and molecular translocation experiments to study the pore structural variation, ion selectivity, ionic conductance and capabilities for sensing several biomolecules. Our results show that the ion selectivity and sensing ability of aerolysin are mostly controlled by electrostatics and the narrow diameter of the double ß-barrel cap. By engineering single-site mutants, a more accurate molecular detection of nucleic acids and peptides has been achieved. These findings open avenues for developing aerolysin nanopores into powerful sensing devices.


Assuntos
Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Ácidos Nucleicos/química , Peptídeos/química , Proteínas Citotóxicas Formadoras de Poros/química , Proteínas Citotóxicas Formadoras de Poros/genética , Toxinas Bacterianas/metabolismo , Cinética , Mutação , Nanoporos , Nanotecnologia , Ácidos Nucleicos/genética , Peptídeos/genética , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Eletricidade Estática
8.
Chem Commun (Camb) ; 55(87): 13096-13099, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31612162

RESUMO

A fluorescence "turn-on" method for digestion-free analysis of 4-thiouridine (s4U) in nucleic acids was developed in this work based on the oxidative amination of s4U by fluoresceinamine (FAM-NH2) and periodate (IO4-). It was 125-fold more sensitive for s4U detection than the traditional UV330 absorption method, and showed excellent selectivity to s4U over 2-thiouridine (s2U) analogues and biological thiols.


Assuntos
Fluorescência , Ácidos Nucleicos/química , Tiouridina/análise , Aminação , Estrutura Molecular , Oxirredução
9.
Molecules ; 24(19)2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31591283

RESUMO

Aptamers are small oligonucleotides that are capable of binding specifically to a target, with impressive potential for analysis, diagnostics, and therapeutics applications. Aptamers are isolated from large nucleic acid combinatorial libraries using an iterative selection process called SELEX (Systematic Evolution of Ligands by EXponential enrichment). Since being implemented 30 years ago, the SELEX protocol has undergone many modifications and improvements, but it remains a laborious, time-consuming, and costly method, and the results are not always successful. Each step in the aptamer selection protocol can influence its results. This review discusses key technical points of the SELEX procedure and their influence on the outcome of aptamer selection.


Assuntos
Aptâmeros de Nucleotídeos/química , Primers do DNA/química , Técnica de Seleção de Aptâmeros/métodos , Aptâmeros de Nucleotídeos/síntese química , Primers do DNA/síntese química , DNA de Cadeia Simples/isolamento & purificação , Biblioteca Gênica , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Técnicas de Amplificação de Ácido Nucleico , Ácidos Nucleicos/química , Reação em Cadeia da Polimerase
10.
Mol Cell ; 76(2): 295-305, 2019 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-31604601

RESUMO

Biomolecular condensation is emerging as an essential process for cellular compartmentalization. The formation of biomolecular condensates can be driven by liquid-liquid phase separation, which arises from weak, multivalent interactions among proteins and nucleic acids. A substantial body of recent work has revealed that diverse cellular processes rely on biomolecular condensation and that aberrant phase separation may cause disease. Many proteins display an intrinsic propensity to undergo phase separation. However, the mechanisms by which cells regulate phase separation to build functional condensates at the appropriate time and location are only beginning to be understood. Here, we review three key cellular mechanisms that enable the control of biomolecular phase separation: membrane surfaces, post-translational modifications, and active processes. We discuss how these mechanisms may function in concert to provide robust control over biomolecular condensates and suggest new research avenues that will elucidate how cells build and maintain these key centers of cellular compartmentalization.


Assuntos
Compartimento Celular , Membrana Celular/metabolismo , Ácidos Nucleicos/metabolismo , Processamento de Proteína Pós-Traducional , Transporte Proteico , Proteínas/metabolismo , Animais , Membrana Celular/química , Endocitose , Humanos , Membranas Intracelulares/metabolismo , Chaperonas Moleculares/metabolismo , Conformação de Ácido Nucleico , Ácidos Nucleicos/química , Conformação Proteica , Proteínas/química , Solubilidade , Relação Estrutura-Atividade
11.
Molecules ; 24(20)2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31615053

RESUMO

We report a universal smart probe (SP) that is capable of detecting several homologous let-7 microRNAs (miRNAs). While the SP is complementary to let-7a, and therefore, strongly binds to this target, due to sequence homology, the SP also has equal propensity to non-specifically hybridize with let-7b and let-7c, which are homologous to let-7a. The fluorescence signal of the SP was switched off in the absence of any homologous member target, but the signal was switched on when any of the three homologous members was present. With the assistance of nucleic acid blockers (NABs), this SP system can discriminate between homologous miRNAs. We show that the SP can discriminate between let-7a and the other two sequences by using linear NABs (LNABs) to block non-specific interactions between the SP and these sequences. We also found that LNABs used do not cross-react with the let-7a target due to the low LNABs:SP molar ratio of 6:1 used. Overall, this SP represents a universal probe for the recognition of a homologous miRNA family. The assay is sensitive, providing a detection limit of 6 fmol. The approach is simple, fast, usable at room temperature, and represents a general platform for the in vitro detection of homologous microRNAs by a single fluorescent hairpin probe.


Assuntos
MicroRNAs/genética , Técnicas de Amplificação de Ácido Nucleico , Ácidos Nucleicos/genética , Corantes Fluorescentes/química , Humanos , Limite de Detecção , MicroRNAs/isolamento & purificação , Conformação de Ácido Nucleico , Ácidos Nucleicos/química , Homologia de Sequência
12.
Soft Matter ; 15(36): 7108-7116, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31482930

RESUMO

In biological systems, it is well-known that the activities and functions of biomacromolecules are dictated not only by their primary chemistries, but also by their secondary, tertiary, and quaternary hierarchical structures. Achieving control of similar levels in synthetic macromolecules is yet to be demonstrated. Most of the critical molecular parameters associated with molecular and hierarchical structures, such as size, composition, topology, sequence, and stereochemistry, are heterogenous, which impedes the exploration and understanding of structure formation and manipulation. Alternatively, in the past few years we have developed a unique giant molecule system based on molecular nanoparticles, in which the above-mentioned molecular parameters, as well as interactions, are precisely defined and controlled. These molecules could self-assemble into a myriad of unconventional and unique structures in the bulk, thin films, and solution. Giant molecules thus offer a robust platform to manipulate the hierarchical structures via precise and modular assemblies of building blocks in an amplified size level compared with small molecules. It has been found that they are not only scientifically intriguing, but also technologically relevant.


Assuntos
Substâncias Macromoleculares/química , Nanopartículas/química , Dimerização , Estrutura Molecular , Ácidos Nucleicos/química , Tamanho da Partícula , Transição de Fase , Polímeros/química , Propriedades de Superfície , Temperatura Ambiente
13.
Chemistry ; 25(53): 12303-12307, 2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31373735

RESUMO

Triplex forming oligonucleotides are used as a tool for gene regulation and in DNA nanotechnology. By incorporating artificial nucleic acids, target affinity and biological stability superior to that of natural DNA may be obtained. This work demonstrates how a chimeric clamp consisting of acyclic (L)-threoninol nucleic acid (aTNA) and DNA can bind DNA and RNA by the formation of a highly stable triplex structure. The (L)-aTNA clamp is released from the target again by the addition of a releasing strand in a strand displacement type of reaction. It is shown that the clamp efficiently inhibits Bsu and T7 RNA polymerase activity and that polymerase activity is reactivated by displacing the clamp. The clamp was successfully applied to the regulation of luciferase expression by reversible binding to the mRNA. When targeting a sequence in the double stranded plasmid, 40 % downregulation of protein expression is achieved.


Assuntos
RNA Polimerases Dirigidas por DNA/química , DNA/química , Ácidos Nucleicos/química , RNA/química , Proteínas Virais/química , Amino Álcoois/química , Butileno Glicóis/química , RNA Polimerases Dirigidas por DNA/metabolismo , RNA Polimerases Dirigidas por DNA/farmacologia , Proteínas Virais/metabolismo , Proteínas Virais/farmacologia
14.
Nat Commun ; 10(1): 3805, 2019 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-31444344

RESUMO

The versatile and tunable self-assembly properties of nucleic acids and engineered nucleic acid constructs make them invaluable in constructing microscale and nanoscale devices, structures and circuits. Increasing the complexity, functionality and ease of assembly of such constructs, as well as interfacing them to the macroscopic world requires a multifaceted and programmable fabrication approach that combines efficient and spatially resolved nucleic acid synthesis with multiple post-synthetic chemical and enzymatic modifications. Here we demonstrate a multi-level photolithographic patterning approach that starts with large-scale in situ surface synthesis of natural, modified or chimeric nucleic acid molecular structures and is followed by chemical and enzymatic nucleic acid modifications and processing. The resulting high-complexity, micrometer-resolution nucleic acid surface patterns include linear and branched structures, multi-color fluorophore labeling and programmable targeted oligonucleotide immobilization and cleavage.


Assuntos
Técnicas Biossensoriais/instrumentação , Microtecnologia/métodos , Ácidos Nucleicos/química , Reagentes para Ligações Cruzadas/química , Fluorescência , Luz , Conformação de Ácido Nucleico/efeitos da radiação , Ácidos Nucleicos/efeitos da radiação , Oligonucleotídeos/química , Oligonucleotídeos/efeitos da radiação , Processos Fotoquímicos/efeitos da radiação
15.
Eur J Pharm Biopharm ; 143: 61-69, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31445157

RESUMO

Localized aerosol delivery of gene therapies is a promising treatment of severe pulmonary diseases including lung cancer, cystic fibrosis, COPD and asthma. The administration of drugs by inhalation features multiple benefits including an enhanced patient acceptability and compliance. The application of a spray dried powder formulation has advantages over solutions due to their increased stability and shelf life. Furthermore, optimal sizes of the powder can be obtained by spray drying to allow a deep lung deposition. The present study optimized the parameters involved with spray drying polyplexes formed by polyethylenimine (PEI) and nucleic acids in inert excipients to generate a nano-embedded microparticle (NEM) powder with appropriate aerodynamic diameter. Furthermore, the effects of the excipient matrix used to generate the NEM powder on the biological activity of the nucleic acid and the ability to recover the embedded nanoparticles was investigated. The study showed that bioactivity and nucleic acid integrity was preserved after spray drying, and that polyplexes could be reconstituted from the dry powders made with trehalose but not mannitol as a stabilizer. Scanning electron microscopy (SEM) showed trehalose formulations that formed fused, lightly corrugated spherical particles in the range between 1 and 5 µm, while mannitol formulations had smooth surfaces and consisted of more defined particles. After redispersion of the microparticles in water, polyplex dispersions are obtained that are comparable to the initial formulations before spray drying. Cellular uptake and transfection studies conducted in lung adenocarcinoma cells show that redispersed trehalose particles performed similar to or better than polyplexes that were not spray dried. A method for quantifying polymer and nucleic acid loss following spray drying was developed in order to ensure that equal nucleic acid amounts were used in all in vitro experiments. The results confirm that spray dried NEM formulations containing nucleic acids can be prepared with characteristics known to be optimal for inhalation therapy.


Assuntos
Nanopartículas/química , Ácidos Nucleicos/química , Polietilenoimina/química , Pós/química , Células A549 , Administração por Inalação , Aerossóis/química , Varredura Diferencial de Calorimetria/métodos , Linhagem Celular Tumoral , Química Farmacêutica/métodos , Dessecação/métodos , Excipientes/química , Humanos , Manitol/química , Microscopia Eletrônica de Varredura/métodos , Tamanho da Partícula , Trealose/química
16.
Photochem Photobiol Sci ; 18(10): 2449-2460, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31407765

RESUMO

Glycol nucleic acids (GNA) are synthetic genetic-like polymers with an acyclic three-carbon propylene glycol phosphodiester backbone. Here, synthesis, luminescence properties, circular dichroism (CD) spectra, and confocal microscopy speciation studies of (R,S) and (S,R) pyrenyl-GNA (pyr-GNA) nucleosides are reported in HeLa cells. Enantiomerically pure nucleosides were obtained by a Sharpless asymmetric dihydroxylation reaction followed by semi-preparative high-performance liquid chromatography (HPLC) separation using Amylose-2 as the chiral stationary phase. The enantiomeric relationship between stereoisomers was confirmed by CD spectra, and the absolute configurations were assigned based on experimental and theoretical CD spectra comparisons. The pyr-GNA nucleosides were not cytotoxic against human cervical (HeLa) cancer cells and thus were utilized as luminescent probes in the imaging of these cells with confocal microscopy. Cellular staining patterns were identical for both enantiomers in HeLa cells. Compounds showed no photocytotoxic effect and were localized in the lipid membranes of the mitochondria, in cellular vesicles and in other lipid cellular compartments. The overall distribution of the pyrene and pyrenyl-GNA nucleosides inside the living HeLa cells differed, since the former compound gives a more granular staining pattern and the latter a more diffuse one.


Assuntos
Corantes Fluorescentes/química , Microscopia Confocal , Ácidos Nucleicos/química , Nucleosídeos/síntese química , Pirenos/química , Sobrevivência Celular/efeitos dos fármacos , Dicroísmo Circular , Cristalografia por Raios X , Teoria da Densidade Funcional , Corantes Fluorescentes/síntese química , Glicóis/química , Células HeLa , Humanos , Conformação Molecular , Nucleosídeos/química , Nucleosídeos/farmacologia , Estereoisomerismo
17.
Talanta ; 205: 120121, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31450457

RESUMO

The amine decorated carbon quantum dots (NH2-CQDs) were synthesized through ultrasonic method from graphite rods derived CQDs and ammonia hydroxide and utilized as the sensing probes for cobalt (II) ions and nucleic acids. The sensing technique was investigated to be the fluorescence quenching effect, which demonstrated linear relationship between cobalt (II) ions concentration and the emission intensity deviation ratio in the concentration range of 50 nM to 40 µM with the detection limit of 12 nM. In brief, this sensitive and selective detection method was confirmed to demonstrate high potential in cobalt (II) ions detection in real samples and nucleic acid sensing in biological cells.


Assuntos
Cobalto/análise , Corantes Fluorescentes/química , Pontos Quânticos/química , Hidróxido de Amônia/química , Nucléolo Celular/metabolismo , Transferência Ressonante de Energia de Fluorescência/métodos , Grafite/química , Células HeLa , Humanos , Limite de Detecção , Ácidos Nucleicos/química , Ondas Ultrassônicas
19.
Nat Protoc ; 14(8): 2416-2436, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31270509

RESUMO

Soft matter can serve as a template to guide the growth of inorganic components with well-controlled structural features. However, the limited design space of conventional organic and biomolecular templates restricts the complexity and accuracy of templated growth. In past decades, the blossoming of structural DNA nanotechnology has provided us with a large reservoir of delicate-framework nucleic acids with design precision down to a single base. Here, we describe a DNA origami silicification (DOS) approach for generating complex silica composite nanomaterials. By utilizing modified silica sol-gel chemistry, pre-hydrolyzed silica precursor clusters can be uniformly coated onto the surface of DNA frameworks; thus, user-defined DNA-silica hybrid materials with ~3-nm precision can be achieved. More importantly, this method is applicable to various 1D, 2D and 3D DNA frameworks that range from 10 to >1,000 nm. Compared to pure DNA scaffolds, a tenfold increase in the Young's modulus (E modulus) of these composites was observed, owing to their soft inner core and solid silica shell. We further demonstrate the use of solidified DNA frameworks to create 3D metal plasmonic devices. This protocol provides a platform for synthesizing inorganic materials with unprecedented complexity and tailored structural properties. The whole protocol takes ~10 d to complete.


Assuntos
Nanotecnologia/métodos , Ácidos Nucleicos/química , Ácidos Nucleicos/ultraestrutura , Dióxido de Silício/química , Módulo de Elasticidade , Transição de Fase
20.
Phys Chem Chem Phys ; 21(30): 16706-16717, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31321392

RESUMO

Herein, for the first time the complexation ability of a homological series of triphenylphosphonium surfactants (TPPB-n) toward DNA decamers has been explored. Formation of lipoplexes was confirmed by alternative techniques, including dynamic light scattering, indicating the occurrence of nanosized complexes (ca. 100-150 nm), and monitoring the charge neutralization of nucleotide phosphate groups and the fluorescence quenching of dye-intercalator ethidium bromide. The complexation efficacy of TPPB-surfactants toward an oligonucleotide (ONu) is compared with that of reference cationic surfactants. Strong effects of the alkyl chain length and the structure of the head group on the surfactant/ONu interaction are revealed, which probably occur via different mechanisms, with electrostatic and hydrophobic forces or intercalation imbedding involved. Phosphonium surfactants are shown to be capable of disordering lipid bilayers, which is supported by a decrease in the temperature of the main phase transition, Tm. This effect enhances with an increase in the alkyl chain length, indicating the integration of TPPB-n with lipid membranes. This markedly differs from the behavior of typical cationic surfactant cetyltrimethylammonium bromide, which induces an increase in the Tm value. It was demonstrated that the cytotoxicity of TPPB-n in terms of the MTT-test on a human cell line 293T nonmonotonically changes within the homological series, with the highest cytotoxicity exhibited by the dodecyl and tetradecyl homologs.


Assuntos
DNA/química , Bicamadas Lipídicas/química , Ácidos Nucleicos/química , Tensoativos/química , Membrana Celular/efeitos dos fármacos , Células HEK293 , Humanos , Tensoativos/toxicidade
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