RESUMO
Protein sample preparation is a critical and an unsustainable step since it involves the use of tedious methods that usually require high amount of solvents. The development of new materials offers additional opportunities in protein sample preparation. This work explores, for the first time, the potential application of carboxylate-terminated carbosilane dendrimers to the purification/enrichment of proteins. Studies on dendrimer binding to proteins, based on protein fluorescence intensity and emission wavelengths measurements, demonstrated the interaction between carboxylate-terminated carbosilane dendrimers and proteins at all tested pH levels. Interactions were greatly affected by the protein itself, pH, and dendrimer concentration and generation. Especially interesting was the interaction at acidic pH since it resulted in a significant protein precipitation. Dendrimer-protein interactions were modeled observing stable complexes for all proteins. Carboxylate-terminated carbosilane dendrimers at acidic pH were successfully used in the purification/enrichment of proteins extracted from a complex sample. Graphical Abstract Images showing the growing turbidity of solutions containing a mixture of proteins (lysozyme, myoglobin, and BSA) at different protein:dendrimer ratios (1:0, 1:1, 1:8, and 1:20) at acidic pH and SDS-PAGE profiles of the corresponsing supernatants. Comparison of SDS-PAGE profiles for the pellets obtained during the purification of proteins present in a complex sample using a conventional "no-clean" method based on acetone precipitation and the proposed "greener" method using carboxylate-terminated carbosilane dendrimer at a 1:20 protein:dendrimer ratio.
Assuntos
Ácidos Carboxílicos/química , Dendrímeros/química , Muramidase/isolamento & purificação , Mioglobina/isolamento & purificação , Soroalbumina Bovina/isolamento & purificação , Silanos/química , Precipitação Química , Concentração de Íons de Hidrogênio , Simulação de Dinâmica Molecular , Muramidase/química , Mioglobina/química , Proteínas de Plantas/isolamento & purificação , Ligação Proteica , Estrutura Secundária de Proteína , Prunus domestica/química , Sementes/química , Soroalbumina Bovina/química , SolventesRESUMO
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/metabolismoRESUMO
The development of medical nanosystems requires knowledge of their behavior in vivo. Clinical chemistry tests are widely used to estimate the systemic toxicity of nanoparticles. In this paper we have explored the impact of small positively charged nanoparticles-poly(amidoamine), phosphorous and carbosilane dendrimers - on biochemical parameters of standardized serum in vitro. All the dendrimers could shift the main biochemical parameters. Thus, in the case of patients having the normal, but 'boundary', values of biochemical parameters, nanoparticle-induced changes can be wrongly interpreted as evidence of some dysfunctions (hepatic, renal, etc.). Moreover, the effects of nanoparticles of metals, carbon nanotubes, quantum dots, fullerenes, dendrimers having been sized up to 4000 nm and the hundreds of reactive groups, can be significantly higher. Thus, preliminary evaluation of any nanomaterial in vitro is required in clinical chemistry tests before its application in vivo to draw the correct conclusions and benefit animals.