Showing papers on "Nanobiotechnology published in 2007"

Intrinsic peroxidase-like activity of ferromagnetic nanoparticles

Abstract: Nanoparticles containing magnetic materials, such as magnetite (Fe3O4), are particularly useful for imaging and separation techniques. As these nanoparticles are generally considered to be biologically and chemically inert, they are typically coated with metal catalysts, antibodies or enzymes to increase their functionality as separation agents. Here, we report that magnetite nanoparticles in fact possess an intrinsic enzyme mimetic activity similar to that found in natural peroxidases, which are widely used to oxidize organic substrates in the treatment of wastewater or as detection tools. Based on this finding, we have developed a novel immunoassay in which antibody-modified magnetite nanoparticles provide three functions: capture, separation and detection. The stability, ease of production and versatility of these nanoparticles makes them a powerful tool for a wide range of potential applications in medicine, biotechnology and environmental chemistry.

Nanoparticle-enzyme hybrid systems for nanobiotechnology.

Abstract: Biomolecule–nanoparticle (NP) [or quantum-dot (QD)] hybrid systems combine the recognition and biocatalytic properties of biomolecules with the unique electronic, optical, and catalytic features of NPs and yield composite materials with new functionalities. The biomolecule–NP hybrid systems allow the development of new biosensors, the synthesis of metallic nanowires, and the fabrication of nanostructured patterns of metallic or magnetic NPs on surfaces. These advances in nanobiotechnology are exemplified by the development of amperometric glucose sensors by the electrical contacting of redox enzymes by means of AuNPs, and the design of an optical glucose sensor by the biocatalytic growth of AuNPs. The biocatalytic growth of metallic NPs is used to fabricate Au and Ag nanowires on surfaces. The fluorescence properties of semiconductor QDs are used to develop competitive maltose biosensors and to probe the biocatalytic functions of proteases. Similarly, semiconductor NPs, associated with electrodes, are used to photoactivate bioelectrocatalytic cascades while generating photocurrents.

Designer Self‐Assembling Peptide Materials

Abstract: Understanding of macromolecular materials at the molecular level is becoming increasingly important for a new generation of nanomaterials for nanobiotechnology and other disciplines, namely, the design, synthesis, and fabrication of nanodevices at the molecular scale from bottom up. Basic engineering principles for microfabrication can be learned through fully grasping the molecular self-assembly and programmed assembly phenomena. Self- and programmed-assembly phenomena are ubiquitous in nature. Two key elements in molecular macrobiological material productions are chemical complementarity and structural compatibility, both of which require weak and non-covalent interactions that bring building blocks together during self-assembly. Significant advances have been made during the 1990s at the interface of materials chemistry and biology. They include the design of helical ribbons, peptide nanofiber scaffolds for three-dimensional cell cultures and tissue engineering, peptide surfactants for solubilizing and stabilizing diverse types of membrane proteins and their complexes, and molecular ink peptides for arbitrary printing and coating surfaces as well as coiled-coil helical peptides for multi-length scale fractal structures. These designer self-assembling peptides have far reaching implications in a broad spectrum of applications in biology, medicine, nanobiotechnology, and nanobiomedical technology, some of which are beyond our current imaginations. [image: see text]

Nanobiotechnology: protein-nanomaterial interactions.

Abstract: We review recent research that involves the interaction of nanomaterials such as nanoparticles, nanowires, and carbon nanotubes with proteins. We begin with a focus on the fundamentals of the structure and function of proteins on nanomaterials. We then review work in three areas that exploit these interactions: (1) sensing, (2) assembly of nanomaterials by proteins and proteins by nanomaterials, and (3) interactions with cells. We conclude with the identification of challenges and opportunities for the future.

Nano-Surface Chemistry

Abstract: Molecular architecture at the solid-liquid interfaces studies by surface forces measurement adhesion on the nanoscale Langmuir monolayers - fundamentals and relevance to nanotechnology supramolecular organic layer engineering for industrial technology mono- and multilayers of spherical polymer particles prepared by Langmuir-Blodgett and self-assembly techniques studies of wetting and capillary phenomena at nanometer scale with scanning polarization force microscopy nanometric solid deformation of soft materials in capillary phenomena 2D and 3D superlattices - synthesis and collective properties molecular nanotechnology and nanobiotechnology with two-dimensional protein crystals (S-layers) DNA as a material for nanobiotechnology self-assembled DNA/polymer complexes supramolecular assemblies made of biological macromolecules reversed micelles as nanometer-size solvent media engineering of core-shell particles and hollow capsules electro-transport in hydrophilic nanostructured materials electrolytes in nanostructures polymer-clay nanocomposites - synthesis and properties.

Nanobiotechnology: silica breaks through in plants.

Abstract: Designer nanotubes based on mesoporous silica can now penetrate the thick cell walls of plants and deliver DNA and their activators. This opens the way to precisely manipulate gene expression in plants at the single-cell level.

Nanobiotechnology II: More Concepts and Applications

Abstract: Nanobiotechnology II More Concepts and Applications , Nanobiotechnology II More Concepts and Applications , کتابخانه الکترونیک و دیجیتال - آذرسا

Nanobiotechnology of Biomimetic Membranes

Abstract: The Significance of Biomimetic Membrane Nanobiotechnology to Biomedical Applications.- Langmuir-Blodgett Technique for Synthesis of Biomimetic Lipid Membranes.- Liposome Techniques for Synthesis of Biomimetic Lipid Membranes.- Characterization and Analysis of Biomimetic Membranes.- Biomimetic Membranes in Biosensor Applications.

Plenty of Room for Biology at the Bottom: An Introduction to Bionanotechnology

Abstract: Introduction: Nanobiotechnology and Bionanotechnology A Brief Introduction to Nanotechnology Natural Biological Assembly at the Nano-Scale Nanometric Biological Assemblies: Molecular and Chemical Basis for Interaction Molecular Recognition and the Formation of Biological Structures Self-Assembly of Biological and Bio-Inspired Nano-Materials Application of Biological Assemblies in Nanotechnology Medical and Other Applications of Bionanotechnology Future Prospects for Nanobiotechnology and Bionanotechnology Concluding Remarks: The Prospects and Dangers of the Nanobiological Revolution.

Controlled assembly of peptide nanotubes triggered by enzymatic activation of self-immolative dendrimers.

Abstract: Although various building blocks can self-assemble to form ordered structures on the nanoscale, the temporal and spatial control of such processes is key for the technological application of these nanostructures. The ability to precisely control the formation of nanoassemblies by an external signal is highly desirable. The aromatic dipeptide nanotubes [ADNT] represent a unique class of organic nanostructures. These bio-inspired structures are formed by the self-assembly of the core recognition motif of the b-amyloid polypeptide into hollow tubes of remarkable persistence, length and rigidity. Biocompatible and water-soluble ADNT are readily formed under mild conditions from inexpensive starting materials. Furthermore, the ADNTs have remarkable chemical and thermal stability and extraordinary mechanical strength; this makes these nanotubes attractive for various applications. The application of these tubes for the fabrication of metal wires and coaxial nanocables for the organization of platinum nanoparticles, as well as for electrochemical biosensors has been demonstrated. 20] Methodologies were also developed for the horizontal and vertical patterning of aligned ADNT. A limiting factor in the utilization of this system, however, is the ability to temporally control the assembly process. Therefore, we decided to explore the ability of a self-immolative dendritic system to serve as a platform for the controlled assembly of peptide nanotubes. The extremely short length of the peptide building blocks and their ability to self-assemble make these units ideal candidates for controlled assembly applications. Self-immolative dendrimers are a novel class of molecules that can amplify a single cleavage event, which is received at a focal point, into multiple releases of tail groups at the periphery. These dendrimers have been used for the construction of unique dendritic prodrugs that have a specific trigger attached to the focal point, and drug molecules linked to the periphery. Self-immolative dendritic prodrugs that are activated through a single catalytic reaction by a specific enzyme offer significant advantages in the inhibition of tumor growth relative to the monomeric prodrugs, especially if the activating enzyme exists at relatively low levels in the malignant tissue. Here, we explored the potential of a self-immolative dendritic system to serve as a transporter platform for control assembly of the peptide nanostructures. We have recently developed an AB3 self-immolative dendritic system, like 1 that can release three reporter groups upon activation by penicillin G amidase (PGA). The first step of the disassembly is the catalytic cleavage of phenylacetic acid by PGA, followed by the elimination of azaquinone-methide and decarboxylation to release amine intermediate 1a. This amine intermediate further disassembles through triple elimination to release the three drug units (Scheme 1). The disassembly of this molecule after the enzymatic cleavage is based solely on

Imaging Gold Nanoparticles for DNA Sequence Recognition in Biomedical Applications

Abstract: The hybridization of single-stranded oligonucleotide-derivatized gold nanoparticles (Au nanoprobes) with double stranded complementary DNA was directly observed by atomic force microscopy (AFM). This specific interaction is the basis for an Au nanoprobe-based homogeneous assay for specific DNA sequence detection, based on salt-induced particle aggregation that is prevented when a complementary target is present. For long DNA targets (linearized plasmid DNA) complicated hybridized target DNA-Au-nanoprobes structures were formed, that were interpreted as the basis for stability of the Au nanoprobes against salt-induced aggregation. For shorter DNA targets (PCR amplified fragments) hybridization with the Au nanoprobes occurred, in the majority of cases, in the expected location of the DNA target fragment containing the specific sequence. The formation of the observed DNA hybridized structures provides evidence at the molecular level for specific hybridization to the target sequence as the method of binding of the Au nanoprobes.

Nanobiotechnology today: focus on nanoparticles

Abstract: In the recent years the nanobiotechnology field and the Journal of Nanobiotechnology readership have witnessed an increase in interest towards the nanoparticles and their biological effects and applications. These include bottom-up and molecular self-assembly, biological effects of naked nanoparticles and nano-safety, drug encapsulation and nanotherapeutics, and novel nanoparticles for use in microscopy, imaging and diagnostics. This review highlights recent Journal of Nanobiotechnology publications in some of these areas http://www.jnanobiotechnology.com.

Nanobiotechnology and nanomedicine

Abstract: Nanobiotechnology is a new direction in the technological science, which plays a key role in creation of nanodevices for analysis of living systems on a molecular level. Nanomedicine is the application of nanotechnologies in medicine for maintenance and improvement of human life using the knowledge on human organism at a molecular level. Application of nanoparticles and nanomaterials for the diagnostic and therapeutic purposes is now significantly extended in nanomedicine. Use of nanotechnological approaches and nanomaterials opens new prospects for creation of drugs and systems for their directed transport. Implementation of optico-biosensoric, atomic-force, nanowire and nanoporous approaches into genomics and proteomics will significantly enhance the sensitivity and accuracy of diagnostics and will shorten the time of diagnostic procedures that will undoubtedly improve the efficiency of medical treatment. The review highlights data on application of nanobiotechnologies in the field of diagnostics and creation of new drugs.

Stretching and selective immobilization of DNA in SU-8 micro- and nanochannels

Abstract: Nanoimprint lithography is used to fabricate 200nm–10μm wide SU-8 channels reversal imprinted onto Si substrates. The immobilization and stretching of double stranded λ-DNA molecules within the micro- and nanochannels are demonstrated and controlled by varying the hydrophobicity of SU-8 using oxygen plasma exposure. Site-directed immobilization of DNA is achieved by the integration of 10μm wide SU-8 patterns with 6μm gaps into 100μm wide and 1μm deep Si channels.

Biomolecular computation for bionanotechnology

Abstract: Introduction. The State-of-the-Art Molecular Biology and Nanotechnology. Nanobiomachines For Information Processing and Communications. Computing by Biomoleware: Diverse Methods From Diversified Materials. Theoretical Biomolecular Computing. Cellular Biomolecular Computing Based on Signaling Pathways. Comparison of Algorithms of Biomolecular Computing and Molecular Bioinformatics. Emerging Nanobiotechnology in Multi-disciplines. References.

Nanobiotechnology: looking inside cell walls.

Abstract: Carbon nanotubes have been used to probe the properties of bilayer systems resembling living cell membranes. Such experiments could offer new insights into the working of cells.

The effect of surface properties of gold nanoparticles on cellular uptake

Abstract: In this study, we developed GNPs with various types of chemical surface features and evaluated how these features led nanoparticles to selectively bind to different target cell sites. Results showed that selective binding was successful in producing high concentrations in target locations. We also explored the potential application of these GNPs to enhance the cancer cell cytotoxicity induced by radiotherapy.