Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Artigo em Inglês | MEDLINE | ID: mdl-38480514

RESUMO

The biologically produced gold nanoparticles (AuNPs) are novel carriers with promising use in targeted tumor therapy. Still, there are no studies regarding the efficacy of nanoparticle internalization by cancer and noncancer cells. In this study, AuNPs were produced by Fusarium oxysporum and analyzed by spectrophotometry, transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), and Zetasizer. Obtained AuNPs were about 15 nm in size with a zeta potential of -35.8 mV. The AuNPs were added to cancer cells (4T1), noncancer cells (NIH/3T3), and macrophages (RAW264.7). The viability decreased in 4T1 (77 ± 3.74%) in contrast to NIH/3T3 and RAW264.7 cells (89 ± 4.9% and 90 ± 3.5%, respectively). The 4T1 cancer cells also showed the highest uptake and accumulation of Au (∼80% of AuNPs was internalized) as determined by graphite furnace atomic absorption spectroscopy. The lowest amount of AuNPs was internalized by the NIH/3T3 cells (∼30%). The NIH/3T3 cells exhibited prominent reorganization of F-actin filaments as examined by confocal microscopy. In RAW264.7, we analyzed the release of proinflammatory cytokines by flow cytometry and we found the AuNP interaction triggered transient secretion of tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ). In summary, we proved the biologically produced AuNPs entered all the tested cell types and triggered cell-specific responses. High AuNP uptake by tumor cells was related to decreased cell viability, while low nanoparticle uptake by fibroblasts triggered F-actin reorganization without remarkable toxicity. Thus, the biologically produced AuNPs hold promising potential as cancer drug carriers and likely require proper surface functionalization to shield phagocytizing cells.

2.
Sci Rep ; 13(1): 4916, 2023 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-36966192

RESUMO

Enzymotherapy based on DNase I or RNase A has often been suggested as an optional strategy for cancer treatment. The efficacy of such procedures is limited e.g. by a short half-time of the enzymes or a low rate of their internalization. The use of nanoparticles, such as gold nanoparticles (AuNPs), helps to overcome these limits. Specifically, biologically produced AuNPs represent an interesting variant here due to naturally occurring capping agents (CA) on their surface. The composition of the CA depends on the producing microorganism. CAs are responsible for the stabilization of the nanoparticles, and promote the direct linking of targeting and therapeutic molecules. This study provided proof of enzyme adsorption onto gold nanoparticles and digestion efficacy of AuNPs-adsorbed enzymes. We employed Fusarium oxysporum extract to produce AuNPs. These nanoparticles were round or polygonal with a size of about 5 nm, negative surface charge of about - 33 mV, and maximum absorption peak at 530 nm. After the adsorption of DNAse I, RNase A, or Proteinase K onto the AuNPs surface, the nanoparticles exhibited shifts in surface charge (values between - 22 and - 13 mV) and maximum absorption peak (values between 513 and 534 nm). The ability of AuNP-enzyme complexes to digest different targets was compared to enzymes alone. We found a remarkable degradation of ssDNA, and dsDNA by AuNP-DNAse I, and a modest degradation of ssRNA by AuNP-RNase A. The presence of particular enzymes on the AuNP surface was proved by liquid chromatography-mass spectrometry (LC-MS). Using SDS-PAGE electrophoresis, we detected a remarkable digestion of collagen type I and fibrinogen by AuNP-proteinase K complexes. We concluded that the biologically produced AuNPs directly bound DNase I, RNase A, and proteinase K while preserving their ability to digest specific targets. Therefore, according to our results, AuNPs can be used as effective enzyme carriers and the AuNP-enzyme conjugates can be effective tools for enzymotherapy.


Assuntos
Ouro , Nanopartículas Metálicas , Ouro/química , Nanopartículas Metálicas/química , Adsorção , Ribonuclease Pancreático , Endopeptidase K
3.
J Am Chem Soc ; 145(9): 5320-5329, 2023 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-36826345

RESUMO

Whereas modern proteins rely on a quasi-universal repertoire of 20 canonical amino acids (AAs), numerous lines of evidence suggest that ancient proteins relied on a limited alphabet of 10 "early" AAs and that the 10 "late" AAs were products of biosynthetic pathways. However, many nonproteinogenic AAs were also prebiotically available, which begs two fundamental questions: Why do we have the current modern amino acid alphabet and would proteins be able to fold into globular structures as well if different amino acids comprised the genetic code? Here, we experimentally evaluate the solubility and secondary structure propensities of several prebiotically relevant amino acids in the context of synthetic combinatorial 25-mer peptide libraries. The most prebiotically abundant linear aliphatic and basic residues were incorporated along with or in place of other early amino acids to explore these alternative sequence spaces. The results show that foldability was likely a critical factor in the selection of the canonical alphabet. Unbranched aliphatic amino acids were purged from the proteinogenic alphabet despite their high prebiotic abundance because they generate polypeptides that are oversolubilized and have low packing efficiency. Surprisingly, we find that the inclusion of a short-chain basic amino acid also decreases polypeptides' secondary structure potential, for which we suggest a biophysical model. Our results support the view that, despite lacking basic residues, the early canonical alphabet was remarkably adaptive at supporting protein folding and explain why basic residues were only incorporated at a later stage of protein evolution.


Assuntos
Aminoácidos , Proteínas , Aminoácidos/química , Proteínas/química , Peptídeos/genética , Dobramento de Proteína , Biblioteca de Peptídeos
4.
Materials (Basel) ; 15(13)2022 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-35806737

RESUMO

Although there are several research articles on the detection and characterization of protein corona on the surface of various nanoparticles, there are no detailed studies on the formation, detection, and characterization of protein corona on the surface of biologically produced gold nanoparticles (AuNPs). AuNPs were prepared from Fusarium oxysporum at two different temperatures and characterized by spectrophotometry, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). The zeta potential of AuNPs was determined using a Zetasizer. AuNPs were incubated with 3 different concentrations of mouse plasma, and the hard protein corona was detected first by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and then by electrospray liquid chromatography-mass spectrometry (LC-MS). The profiles were compared to AuNPs alone that served as control. The results showed that round and oval AuNPs with sizes below 50 nm were produced at both temperatures. The AuNPs were stable after the formation of the protein corona and had sizes larger than 86 nm, and their zeta potential remained negative. We found that capping agents in the control samples contained small peptides/amino acids but almost no protein(s). After hard protein corona formation, we identified plasma proteins present on the surface of AuNPs. The identified plasma proteins may contribute to the AuNPs being shielded from phagocytizing immune cells, which makes the AuNPs a promising candidate for in vivo drug delivery. The protein corona on the surface of biologically produced AuNPs differed depending on the capping agents of the individual AuNP samples and the plasma concentration.

5.
Pharmaceutics ; 13(10)2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34683842

RESUMO

Cancer is one of the most important problems of modern medicine. At the present time, gene therapy has been developed against cancer, which includes the delivery of anticancer small interfering RNAs (siRNAs) directed at cancer proteins. The prospect of creating drugs based on RNA interference implies the use of delivery systems. Metal nanoparticles are the most studied objects for medicine, including their application as non-viral vectors. We have synthesized gold nanoparticles (AuNPs) modified with cationic carbosilane dendrons of 1-3 generations, with a positive charge on the surface, gold nanoparticles can effectively bind small interfering RNAs. Using a photometric viability test and flow cytometry, we assessed the ability of dendronized gold nanoparticles in delivering siRNAs to tumor cells. The efficiency of the complexes in initiating apoptosis was measured and, also, the overall effect of proapoptotic siRNA on cells. AuNP15 has both the highest efficacy and toxicity. The delivery efficiency in suspension cell lines was 50-60%. Complexes with targeted siRNA decreased cell viability by 20% compared to control and initiated apoptosis.

6.
J Biotechnol ; 331: 48-52, 2021 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-33727080

RESUMO

The interaction of nanoparticles (NP) with proteins (the so-called 'protein corona') is a huge challenge in attempting to apply them in personalized nanomedicine. We have analyzed the interaction between A) two 'soft' NPs (a cationic phosphorus dendrimer of generation 3; a cationic phosphorus amphiphilic dendron of generation 2), and B) one 'hard' nanoparticle (silver NP covered with cationic carbosilane dendritic moieties); and membrane-bound protein phospholipase A2 from bovine pancreas. The hard and soft NPs have differences in the nature of their interactions with phospholipase A2. This enzyme surrounds hard AgNP, whereas dendrimer and amphiphilic dendron form aggregates/micelles with phospholipase A2. There is a difference in action of phospholipase A2 bound to the core of dendrimer, and of micelles formed from non-covalent interactions between the amphiphilic dendron. These data are important in understanding the nature of interaction between different kinds of nanoparticles and proteins.


Assuntos
Dendrímeros , Nanopartículas Metálicas , Nanopartículas , Animais , Bovinos , Micelas , Fosfolipases A2 , Prata
7.
Mater Sci Eng C Mater Biol Appl ; 113: 111020, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32487418

RESUMO

Selection of purification method and type of adsorbent has high significance for separation of a biomolecule like deoxyribonucleic acid (DNA). Nanoflowers are a newly improved class of adsorbent. Due to showing very structural similarity to plant flowers, they are named as nanoflowers. Herein, after synthesize of copper phosphate three hydrate nanoflowers [(Cu3(PO4)2.3H2O), CP-NFs], Fe3+ ions were attached to their surfaces. Obtained Fe3+-CP-NFs, before investigation of some adsorption parameters for DNA, they were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Some attained data from the results of adsorption experiments as follows: While maximum DNA adsorption on Fe3+-CP-NFs was found as an excellent value of 845.8 mg/g, nanoflowers without Fe3+ ions adsorbed DNA as only 25.3 mg/g. Optimum media conditions for DNA adsorption were observed at pH 7 and 25 °C with an initial concentration of 1.5 mg/mL DNA. Langmuir and Freundlich adsorption equations were applied to determine which adsorption model was appropriate, and it was seen that Langmuir model was fit with a R2 of 0.9885.


Assuntos
DNA/química , Imidazóis/química , Ferro/química , Nanoestruturas/química , Adsorção , Cobre/química , DNA/isolamento & purificação , Concentração de Íons de Hidrogênio , Íons/química , Cinética , Fosfatos/química
8.
Colloids Surf B Biointerfaces ; 182: 110354, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325775

RESUMO

Nanoflowers - new nanostructures - have aroused the interest of scientists due to the topographic features of nanolayers, the special location of which allows a higher surface-to-volume ratio compared to classic spherical nanoparticles, which significantly increases the efficiency of surface reactions for nanoflowers. The main purpose of these types of nanomaterials is their use as enzyme stabilizers. To facilitate the functioning of enzymes under different conditions, organic-inorganic hybrid nanomaterials have been developed, the name of which indicates that all components of inorganic nanoparticles are associated with organic materials. These nanoparticles have many promising applications in catalysis, as biosensors, and for drug delivery. Organic-inorganic hybrid nanoflowers have led to the development of a new branch of chemistry - the chemistry of hybrid nanomaterials - in which research is rapidly developing. Thus, studying organic-inorganic hybrid nanocrystals can lead to creative new solutions in the field of chemistry of enzyme systems and the rapid development of bionanomaterials and new biotechnology industries. Present review focuses on wide biomedical applications of nanoflowers including biocatalysis, detection of substances, electrochemical biosensors based on nanoflowers, photosensitizers, drug and gene carriers and detection of various diseases, photothermal and other treatments. It will be interesting for wide range of scientists focusing in topic of new kinds of nanoparticles.


Assuntos
Técnicas Biossensoriais , Estruturas Metalorgânicas/síntese química , Nanomedicina/métodos , Nanoestruturas/química , Nanotecnologia/métodos , Animais , Biocatálise , Sistemas de Liberação de Medicamentos/métodos , Técnicas Eletroquímicas , Humanos , Estruturas Metalorgânicas/ultraestrutura , Nanomedicina/instrumentação , Nanoestruturas/administração & dosagem , Nanoestruturas/ultraestrutura , Nanotecnologia/instrumentação , Tamanho da Partícula , Fármacos Fotossensibilizantes/química , Propriedades de Superfície
9.
Future Med Chem ; 11(14): 1741-1756, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31287722

RESUMO

Coordination of ruthenium arene fragments on carbosilane dendrimers' surface greatly increases their antitumor properties. Newly synthetized ruthenium dendrimers are water-soluble, monodisperse and stable. Since carbosilane dendrimers are good carriers of drugs and genes, the presence of ruthenium in their structure makes them promising candidates for new drug delivery systems with improved antitumor potential. Carbosilane ruthenium dendrimers are more toxic to cancer cells than normal cells. Results of several in vitro studies applied here indicate that carbosilane ruthenium dendrimers induce apoptosis in promyelocytic leukemia HL-60 cells.


Assuntos
Antineoplásicos/farmacologia , Dendrímeros/farmacologia , Leucemia Promielocítica Aguda/tratamento farmacológico , Compostos Organometálicos/farmacologia , Rutênio/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Dendrímeros/síntese química , Dendrímeros/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HL-60 , Humanos , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patologia , Estrutura Molecular , Compostos Organometálicos/síntese química , Compostos Organometálicos/química , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismo , Rutênio/química , Relação Estrutura-Atividade
10.
Colloids Surf B Biointerfaces ; 179: 226-232, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30974260

RESUMO

Dendrimers are hyperbranched polymers for delivery of therapeutic genetic material to cancer cells. The fine tuning chemical modifications of dendrimers allow for the modification of the composition. The architecture and the properties of dendrimers are key factors to improve their in vitro and in vivo properties such as biocompatibility with cells and tissues and their pharmacokinetic/pharmacodynamic behavior. The side effects of dendrimers on structure and function of proteins is an important question that must be addressed. We herein describe the effect of newly synthesized piperidine-based cationic phosphorous dendrimers of 2 generations and commercial cationic, neutral and anionic poly(amidoamine) (PAMAM) dendrimers of 4th generation on immunochemical properties of 2 serum proteins: human serum albumin (HSA) and alpha-1-microglobulin (A1M). Both can bind and transfer ligands in blood, including hormones, fatty acids, toxins and drugs, and have immunoreactivity properties. Comparing the effects of piperidinium-terminated phosphorus and cationic, neutral and anionic PAMAM dendrimers on HSA and A1M, we conclude that, in the case of equimolar complexes, these dendrimers had no significant effect on immunoreactivity of proteins. In contrast, the formation of complexes in which a protein is fully bound to dendrimers leads to partial (1.2-2.3 times) reduction in protein immunoreactivity. The most important fact is that dendrimer-induced change in immunoreactivity of proteins is not complete, even if the protein is entirely bound by dendrimers. This means that the application of dendrimers in vivo will not totally hamper the immunoreactivity of these proteins and antibodies.


Assuntos
alfa-Globulinas/imunologia , Dendrímeros/metabolismo , Albumina Sérica Humana/imunologia , Anticorpos Monoclonais/metabolismo , Antígenos/metabolismo , Dendrímeros/química , Estradiol/metabolismo , Humanos , Eletricidade Estática , Tiroxina/metabolismo
11.
Pharmaceutics ; 10(3)2018 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-30096839

RESUMO

The lack of an appropriate intracellular delivery system for therapeutic nucleic acids (TNAs) is a major problem in molecular biology, biotechnology, and medicine. A relatively new class of highly symmetrical hyperbranched polymers, called dendrimers, shows promise for transporting small TNAs into both cells and target tissues. Dendrimers have intrinsic advantages for this purpose: their physico-chemical and biological properties can be controlled during synthesis, and they are able to transport large numbers of TNA molecules that can specifically suppress the expression of single or multiple targeted genes. Numerous chemical modifications of dendrimers extend the biocompatibility of synthetic materials and allow targeted vectors to be designed for particular therapeutic purposes. This review summarizes the latest experimental data and trends in the medical application of various types of dendrimers and dendrimer-based nanoconstructions as delivery systems for short small interfering RNAs (siRNAs) and microRNAs at the cell and organism levels. It provides an overview of the structural features of dendrimers, indicating their advantages over other types of TNA transporters.

12.
Int J Biol Macromol ; 118(Pt B): 1773-1780, 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-29997045

RESUMO

Functionalization of gold nanoparticles by different chemical groups is an important issue regarding the biomedical applications of such particles. Therefore we have analyzed the interaction between gold nanoparticles functionalized by carbosilane dendrons with human serum albumin at different pHs, and in the presence of the protein unfolding agent, guanidine hydrochloride, using circular dichroism, zeta-potential and fluorescence quenching. The effect of a nanoparticle dendronization and pure dendrons on the immunoreactivity of albumin was estimated using ELISA. In addition, the tool to estimate the binding capacity of dendronized gold nanoparticles using a hydrophobic fluorescent probe 1,8-ANS (1-anilinonaphthalene-8-sulfonic acid) was chosen. We concluded that the effect of a nanoparticle on the structure, immunochemical properties and unfolding of albumin significantly decreased with second and third generations dendrons attached. Differences in pH dependence of the interaction between nanoparticles, their dendrons and albumin showed several effects of the "dendritic corona" and the metallic part of nanoparticle on the protein. These interactions indicate changes in the immunoreactivity of the protein, whereas dendron coating per se had no effect. Thus, dendronization of gold nanoparticles helps to shield them from interactions with plasma proteins.


Assuntos
Cátions , Dendrímeros , Ouro , Nanopartículas Metálicas , Albumina Sérica Humana/química , Silanos , Cátions/química , Dicroísmo Circular , Dendrímeros/química , Ouro/química , Humanos , Concentração de Íons de Hidrogênio , Cinética , Nanopartículas Metálicas/química , Ligação Proteica , Albumina Sérica Humana/metabolismo , Silanos/química , Relação Estrutura-Atividade
13.
Int J Biol Macromol ; 108: 936-941, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29104054

RESUMO

Gold nanoparticles are new kinds of nanomaterials. Their large surface-to-volume ratio, stability, excellent biocompatibility, low toxicity and functionality make them very attractive for biomedical applications. Therefore we have analyzed how dendronized gold nanoparticles interact with human alpha-1-microglobulin. This is a glycoprotein of ∼30kDa present in blood plasma and some tissues of the human body. Comparing 3 nanoparticles with different dendronization, we conclude that the effect of a nanoparticle on the structure of alpha-1-microglobulin significantly decreased with second and third generations dendrons as a result of less exposure of the metal cores in the nanoparticles. These interactions indicate weak changes in the immunochemical properties of the protein, whereas the dendron coating had no effect. Thus, dendronization of gold nanoparticles helps to modify their binding properties by shielding them from interactions with plasma proteins.


Assuntos
alfa-Globulinas/química , Dendrímeros/química , Ouro/química , Nanopartículas Metálicas/química , Humanos , Modelos Moleculares , Tamanho da Partícula , Conformação Proteica
14.
Colloids Surf B Biointerfaces ; 152: 414-422, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-28167455

RESUMO

Dendrimers are hyperbranched polymers belonging to the huge class of nanomedical devices. Their wide application in biology and medicine requires understanding of the fundamental mechanisms of their interactions with biological systems. Summarizing, electrostatic force plays the predominant role in dendrimer-protein interactions, especially with charged dendrimers. Other kinds of interactions have been proven, such as H-bonding, van der Waals forces, and even hydrophobic interactions. These interactions depend on the characteristics of both participants: flexibility and surface charge of a dendrimer, rigidity of protein structure and the localization of charged amino acids at its surface. pH and ionic strength of solutions can significantly modulate interactions. Ligands and cofactors attached to a protein can also change dendrimer-protein interactions. Binding of dendrimers to a protein can change its secondary structure, conformation, intramolecular mobility and functional activity. However, this strongly depends on rigidity versus flexibility of a protein's structure. In addition, the potential applications of dendrimers to nanomedicine are reviwed related to dendrimer-protein interactions.


Assuntos
Dendrímeros/química , Nanomedicina/métodos , Proteínas/química , Aminoácidos/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Estrutura Secundária de Proteína
15.
Colloids Surf B Biointerfaces ; 134: 377-83, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26218524

RESUMO

Protein absorption at the surface of big nanoparticles and formation of 'protein corona' can completely change their biological properties. In contrast, we have studied the binding of small nanoparticles - dendrimers - to proteins and the formation of their 'nanoparticle corona'. Three different types of interactions were observed. (1) If proteins have rigid structure and active site buried deeply inside, the 'nanoparticle corona' is unaffected. (2) If proteins have a flexible structure and their active site is also buried deeply inside, the 'nanoparticle corona' affects protein structure, but not enzymatic activity. (3) The 'nanoparticle corona' changes both the structure and enzymatic activity of flexible proteins that have surface-based active centers. These differences are important in understanding interactions taking place at a bio-nanointerface.


Assuntos
Dendrímeros/química , Nanopartículas/química , Proteínas/química , Dicroísmo Circular , Microscopia Eletrônica de Varredura , Estrutura Secundária de Proteína
16.
Int J Pharm ; 485(1-2): 288-94, 2015 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-25796120

RESUMO

This paper examines a perspective to use newly engineered nanomaterials as effective and safe carriers for gene therapy of cancer. Three different groups of cationic dendrimers (PAMAM, phosphorus, and carbosilane) were complexed with anticancer siRNA and the biophysical properties of the dendriplexes created were analyzed. The potential of the dendrimers as nanocarriers for anticancer Bcl-xl, Bcl-2, Mcl-1 siRNAs and additionally a scrambled sequence siRNA has been explored. Dendrimer/siRNA complexes were characterised by various methods including fluorescence, zeta potential, dynamic light scattering, circular dichroism, gel electrophoresis and transmission electron microscopy. In this part of study, the transfection of complexes in HeLa and HL-60 cells was analyzed using both single apoptotic siRNAs and a mixture (cocktail) of them. Cocktails were more effective than single siRNAs, allowing one to decrease siRNAs concentration in treating cells. The dendrimers were compared as siRNA carriers, the most effective being the phosphorus-based ones. However, they were also the most cytotoxic on their own, so that in this regard the application of all dendrimers in anticancer therapy will be discussed.


Assuntos
Dendrímeros/química , Neoplasias/terapia , Fósforo/química , RNA Interferente Pequeno/genética , Terapêutica com RNAi/métodos , Silanos/química , Transfecção/métodos , Apoptose , Sobrevivência Celular , Dicroísmo Circular , Dendrímeros/toxicidade , Eletroforese em Gel de Ágar , Regulação Neoplásica da Expressão Gênica , Células HL-60 , Células HeLa , Heparina/química , Humanos , Luz , Microscopia Eletrônica de Transmissão , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Conformação de Ácido Nucleico , Tamanho da Partícula , Fósforo/toxicidade , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/química , RNA Interferente Pequeno/metabolismo , Espalhamento de Radiação , Silanos/toxicidade , Espectrometria de Fluorescência , Proteína bcl-X/genética , Proteína bcl-X/metabolismo
17.
Int J Pharm ; 485(1-2): 261-9, 2015 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-25791760

RESUMO

This paper examines a perspective on the use of newly engineered nanomaterials as effective and safe carriers of genes for the therapy of cancer. Three different groups of cationic dendrimers (PAMAM, phosphorus and carbosilane) were complexed with anticancer siRNA and their biophysical properties of the dendriplexes analyzed. The potential of the dendrimers as nanocarriers for anticancer siBcl-xl, siBcl-2, siMcl-1 siRNAs and a siScrambled sequence was explored. Dendrimer/siRNA complexes were characterized by methods including fluorescence, zeta potential, dynamic light scattering, circular dichroism, gel electrophoresis and transmission electron microscopy. Some of the experiments were done with heparin to check if siRNA can be easily disassociated from the complexes, and whether released siRNA maintains its structure after interaction with the dendrimer. The results indicate that siRNAs form complexes with all the dendrimers tested. Oligoribonucleotide duplexes can be released from dendriplexes after heparin treatment and the structure of siRNA is maintained in the case of PAMAM or carbosilane dendrimers. The dendrimers were also effective in protecting siRNA from RNase A activity. The selection of the best siRNA carrier will be made based on cell culture studies (Part B).


Assuntos
Dendrímeros/química , Fósforo/química , RNA Interferente Pequeno/química , Terapêutica com RNAi/métodos , Silanos/química , Transfecção , Dicroísmo Circular , Eletroforese em Gel de Ágar , Regulação Neoplásica da Expressão Gênica , Heparina/química , Humanos , Luz , Microscopia Eletrônica de Transmissão , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/terapia , Conformação de Ácido Nucleico , Tamanho da Partícula , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Espalhamento de Radiação , Espectrometria de Fluorescência , Transfecção/métodos , Proteína bcl-X/genética , Proteína bcl-X/metabolismo
18.
J Control Release ; 181: 40-52, 2014 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-24607663

RESUMO

This paper reviews the biodistribution, toxicity and pharmacokinetics of pure dendrimers and their complexes with nucleic acids (dendriplexes) in animals, including mice, rats, rabbits, and guinea pigs. Methods and results will both be discussed. The paradigm about dendrimers' toxicity based on in vitro studies should be revised; almost all dendrimers of low and middle generations are non-toxic in vivo, despite showing some cytotoxic effects in vitro. Only the high generations of unmodified cationic dendrimers in high doses have some toxicity in vivo. Modifications of dendrimers decrease their toxicity, even when this has already been acceptable with regard to unmodified dendrimers. Several undesirable effects following administration of unmodified cationic dendrimers diminish during prolonged dosing because of the development of counteracting mechanisms. Disturbances tend to return to normal levels during the recovery period after dendrimers have ceased to be administered to animals. Neutralization of the surface charge of dendrimers in their dendriplexes leads to less toxicity in vivo. Although dendrimers and dendriplexes accumulate temporarily in liver, pancreas, heart, and kidneys, they do not do permanent damage to them, i.e. the risk of irreversible damage or malfunction of these internal organs is slight. Chemical modifications of dendrimers determine the desired location of multifunctional dendrimer-based conjugates and dendriplexes in a targeted organ. Clearance of dendrimers also strongly depends on their chemical structure. When nucleic acids are complexed with dendrimers (forming so-called dendriplexes), they are more stable, having longer circulation times than free and PEI-complexed ones. Dendrimers are highly efficient in transfection and can be targeted to any organ, e.g. brain, lung and kidneys. The vast majority of dendrimers and dendriplexes are non-immunogenic. To sum up, these promising results from in vivo studies open up the possibility of dendrimers being applied as a new generation of nano-therapeutic agents in medicine, especially in human gene therapy.


Assuntos
Dendrímeros , Portadores de Fármacos , Técnicas de Transferência de Genes , Ácidos Nucleicos/administração & dosagem , Animais , Cátions , Dendrímeros/química , Dendrímeros/farmacocinética , Dendrímeros/toxicidade , Portadores de Fármacos/química , Portadores de Fármacos/farmacocinética , Portadores de Fármacos/toxicidade , Cobaias , Camundongos , Ácidos Nucleicos/farmacocinética , Ácidos Nucleicos/toxicidade , Coelhos , Ratos , Distribuição Tecidual
19.
Colloids Surf B Biointerfaces ; 109: 183-9, 2013 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-23643914

RESUMO

Treatment of HIV infection by gene therapy is a promising tool for combating AIDS. One of the primary limitations of gene therapy is the effective delivery of nucleic acids to the target cells. Dendrimers are nanoparticles that are increasingly being used as nucleic acid vehicles. We have synthesized "Si-C" amino-terminated carbosilane dendrimers [GnO3(NMe3)m](m+) functionalized with quaternary ammonium (NMe3(+)) terminal groups via hydrosilylation of allyl dimethylamine with the corresponding GnO3(SiH)m dendrimers and further addition of MeI. These dendrimers are soluble in water. Initially, complexation between these "Si-C" dendrimers and anti-HIV nucleic acids (oligodeoxynucleotides ANTITAR and GEM91, siRNA siP24) was studied and molar ratios for complete complexation were determined. Then the charge and size of the dendriplexes (complexes of "Si-C" dendrimers with nucleic acids) were analyzed and it was found that they possessed charges of +5 to +40 mV and sizes of 60-600 nm (zeta-size) or 50-100 nm (atomic force microscopy) suitable for cell transfection. Stability studies showed that the dendriplexes were stable over time and were resistant to degradation by serum albumin. The effects of dendrimers and their dendriplexes on erythrocytes (isolated and in whole blood) revealed that the dendriplexes were significantly less cytotoxic than the pure dendrimers. The effects of dendrimers and their dendriplexes on peripheral blood mononuclear cells (the main target of HIV) were analyzed and it was found that the dendriplexes were 10 times less cytotoxic than the pure dendrimers. Finally, transfection experiments revealed that "Si-C"-carbosilane dendrimers had a restricted ability to deliver long-chain double-stranded nucleic acids. The results indicate that these cationic carbosilane dendrimers are good candidates for delivering short-chain siRNA and oligodeoxynucleotide to HIV-infected peripheral blood mononuclear cells or lymphocytes.


Assuntos
Fármacos Anti-HIV/química , Dendrímeros/química , Portadores de Fármacos/química , Portadores de Fármacos/farmacologia , Leucócitos Mononucleares/efeitos dos fármacos , Ácidos Nucleicos/química , Silanos/química , Sobrevivência Celular , Dendrímeros/síntese química , Dendrímeros/farmacologia , Portadores de Fármacos/síntese química , Terapia Genética , Humanos , Leucócitos Mononucleares/química , Leucócitos Mononucleares/virologia , Linfócitos/química , Linfócitos/efeitos dos fármacos , Linfócitos/virologia , Tamanho da Partícula , Silanos/síntese química , Silanos/farmacologia , Eletricidade Estática , Relação Estrutura-Atividade , Propriedades de Superfície
20.
J Phys Chem B ; 116(50): 14525-32, 2012 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-23199071

RESUMO

There are several barriers to the application of dendriplexes formed by poly(propylene imine) dendrimers and genetic material for gene therapy. One limitation is their interaction with extracellular matrix components such as glucosaminoglycans. These can displace the genetic material from the dendriplexes, affecting their transfection activity. In this study, we analyzed the interaction between dendriplexes and the four main glucosaminoglycans (heparin, heparan sulfate, chondroitin sulfate, and hyaluronic acid) by fluorescence polarization and gel electrophoresis. Dendriplexes were formed by combining three anti-HIV antisense oligodeoxynucleotides with three poly(propylene imine) dendrimers of the fourth generation: unmodified and partially modified with maltose and maltotriose (open shell glycodendrimers). The data showed that the effect of glucosaminoglycans on dendriplexes depends on the glucosaminoglycan type and the oligosaccharide serving as the surface group of the dendrimer. Heparin at physiological concentrations destroys dendriplexes formed by open shell glycodendrimers, but dendriplexes based on unmodified poly(propylene imine) dendrimers are stable in its presence. The other glucosaminoglycans at physiological concentrations cannot destroy dendriplexes formed by any of the dendrimers studied.


Assuntos
Dendrímeros/química , Glicosaminoglicanos/química , HIV-1/genética , Oligonucleotídeos Antissenso/química , Polipropilenos/química , Sequência de Bases , Estabilidade de Medicamentos , Eletroforese , Polarização de Fluorescência , Terapia Genética , Modelos Moleculares , Conformação Molecular , Oligonucleotídeos Antissenso/genética , Tamanho da Partícula
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...