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1.
Dalton Trans ; 2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31932819

RESUMO

Correction for 'Azamacrocycles and tertiary amines can be used to form size tuneable hollow structures or monodisperse oxide nanoparticles depending on the 'M' source' by Graham E. Tilburey, et al., Dalton Trans., 2019, 48, 15470-15479.

2.
Langmuir ; 35(44): 14230-14237, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31609123

RESUMO

This paper describes novel adaptations of optically sectioned planar format assays to screen compounds for their affinities to materials surfaces. The novel platform, which we name optically sectioned indicator displacement assays (O-IDA), makes use of displaceable dyes in a format adaptable to high-throughput multiwell plate technologies. We describe two approaches: the first being where the dye exhibits fluorescence in both the surface bound and unbound state and the second, where fluorescence is lost upon displacement of the dye from the surface. Half maximal inhibitory concentration (IC50), binding affinity (Ki), and binding free energy (ΔGads) values can be extracted from the raw data. Representative biomolecules were tested for interactions with silica in an aqueous environment and ZnO(0001)-Zn and (10-10) facets in a nonaqueous environment. We provide the first experimental values for both the binding of small molecules to silica and the facet-dependent ZnO binding affinity of key amino acids associated with ZnO-specific oligopeptides. The specific data will be invaluable to those studying interactions at interfaces both experimentally and computationally. O-IDA provides a general framework for the high-throughput screening of molecule binding to materials surfaces, which has important applications in drug delivery, (bio-) catalysis, biosensing, and biomaterial engineering.

3.
Org Lett ; 21(19): 7902-7907, 2019 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-31524401

RESUMO

There is high demand for new methods to modify peptides, for application in drug discovery and biomedicine. A C-H functionalization protocol for the olefination of tryptophan residues in peptides is described. The modification is successful for Trp residues at any position in the peptide, has broad scope in the styrene coupling partner, and offers opportunities for conjugating peptides with other biomolecules. For peptides containing both Trp and Phe, directing group manipulation enables full control of residue selectivity.

4.
Dalton Trans ; 48(41): 15470-15479, 2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31259981

RESUMO

We show that the azamacrocycle 'cyclam' (1,4,8,11-tetraazacyclodecane) in conjunction with a silicon catecholate ion generates novel hollow tetragonal tube-like crystalline materials [(C6H4O2)3Si][C10H26N4]·H2O, whose dimensions can be tuned according to the pH of the reaction medium. The synthesis approach was successful for both silicon and germanium and we hypothesise that a range of other catecholate precursors of elements such as iron could be used to generate a large array of inorganic materials with interesting morphologies. The synthesis approach can be extended to tertiary diamines with functional group spacing playing an important role in the efficacy of complexation. Of the molecules explored to date, a C2 spacing (N,N,N',N'-tetramethylethylenediamine (4MEDAE)), leads to the most efficient structure control with hollow hexagonal tube-like structures being formed. In addition, we show that azamacrocycles, in the presence of unbuffered tetramethoxysilane (TMOS) solutions can be used to manipulate silica formation and provide a fast (ca. 10 minutes) synthesis route to particles whose diameter can be tuned from ca. 20 nm to several hundreds of nm under reaction conditions (no extremes of pH) that make the sols suitable for direct use in biotechnological applications.

5.
Front Plant Sci ; 10: 210, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30891051

RESUMO

Equisetum species are primitive vascular plants that benefit from the biogenesis of silica bio-organic inclusions in their tissues and participate in the annual biosilica turnover in local eco-systems. As means of Equisetum reproduction and propagation, spores are expected to reflect the evolutionary adaptation of the plants to the climatic conditions at different times of the year. Combining methods of Raman and scanning electron microscopy and assisted with density functional theory, we conducted material spatial-spectral correlations to characterize the distribution of biopolymers and silica based structural elements that contribute to the bio-mineral content of the elater. The elater tip has underlying skeletal-like structural elements where cellulose fibers provide strength and flexibility, both of which are necessary for locomotion. The surface of the elater tips is rich with less ordered pectin like polysaccharide and shows a ridged, folded character. At the surface we observe silica of amorphous, colloidal form in nearly spherical structures where the silica is only a few layers thick. We propose the observed expansion of elater tips upon germination and the form of silica including encapsulated biopolymers are designed for ready dispersion, release of the polysaccharide-arginine rich content and to facilitate silica uptake to the developing plant. This behavior would help to condition local soil chemistry to facilitate competitive rooting potential and stem propagation.

6.
Phys Chem Chem Phys ; 21(8): 4663-4672, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30747204

RESUMO

Polypeptide based biosilica composites show promise as next generation multi-functional nano-platforms for diagnostics and bio-catalytic applications. Following the identification of a strong silica binder (LDHSLHS) by phage display, we conduct structural analysis of the polypeptide at the interface with amorphous silica nanoparticles in an aqueous environment. Our approach relies on modelling infrared and Raman spectral responses using predictions of molecular dynamics simulations and quantum studies of the normal modes for several potential structures. By simultaneously fitting both infrared and Raman responses in the amide spectral region, we show that the main structural conformer has a beta-like central region and helix-twisted terminals. Classical simulations, as conducted previously (Chem. Mater., 2014, 26, 5725), predict that the association of the main structure with the interface is stimulated by electrostatic interactions though surface binding also requires spatially distributed sodium ions to compensate for negatively charged acidic silanol groups. Accordingly, diffusion of sodium ions would contribute to a stochastic character of the peptide association with the surface. Consistent with the described dynamics at the interface, the results obtained from isothermal titration calorimetry (ITC) confirm a significant enhancement of polypeptide binding to silica at higher concentrations of Na+. The results of this study suggest that the tertiary structure of a phage capsid protein plays a significant role in regulating the conformation of peptide LDHSLHS, increasing its binding to silica during the phage display process. The results presented here support design-led engineering of polypeptide-silica nanocomposites for bio-technological applications.


Assuntos
Peptídeos/química , Dióxido de Silício/química , Sítios de Ligação , Técnicas de Visualização da Superfície Celular , Simulação de Dinâmica Molecular , Nanopartículas/química , Tamanho da Partícula , Ligação Proteica , Sódio/química , Eletricidade Estática , Relação Estrutura-Atividade , Propriedades de Superfície , Termodinâmica , Água/química
7.
Artigo em Inglês | MEDLINE | ID: mdl-30763147

RESUMO

Calcium carbonate (E170) is a common food and pharmaceutical additive/ingredient. In addition to a source of calcium, the carbonate has uses including as a colour, acidity regulator and bulking agent. Globally, a range of regulatory agencies and pharmacopoeia control the analyses and specification of additives in food, supplements, pharmaceutical substances and excipients. Accordingly, a range of specifications and analyses exist for calcium carbonate depending on the application and market of the product. In this contribution, we analyse calcium carbonates from geological, synthetic and biogenic sources, focussing on acid insoluble impurities, a test required by current monographs. Analysis of calcium carbonate from different origins may require modification of existing tests to comply with regulatory bodies, due to the variation of impurities specific to the source of the material. We suggest an analytical approach involving centrifugation that improves analytical efficiency (up to 85% time reduction), especially for calcium carbonate of biological origin.


Assuntos
Carbonato de Cálcio/análise , Aditivos Alimentares/análise , Centrifugação , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
8.
Org Lett ; 21(1): 104-108, 2019 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-30543424

RESUMO

New methods for peptide modification are in high demand in drug discovery, chemical biology, and materials chemistry; methods that modify natural peptides are particularly attractive. A Pd-catalyzed, C-H functionalization protocol for the olefination of phenylalanine residues in peptides is reported, which is compatible with common amino acid protecting groups, and the scope of the styrene reaction partner is broad. Bidentate coordination of the peptide to the catalyst appears crucial for the success of the reaction.


Assuntos
Peptídeos/síntese química , Fenilalanina/química , Catálise , Estrutura Molecular , Paládio/química , Peptídeos/química
9.
Phys Chem Chem Phys ; 21(3): 1344-1353, 2019 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-30575829

RESUMO

A diversity of photo-switching structural elements opens up new opportunities in the engineering of light driven reshaping of matter, in catalysis on-click including photodynamic cancer therapy, in light sensitive transport control and in data storage. With the assistance of quantum calculations we explore the photo-physical properties of novel 3,3'-azothiophene molecular systems, the synthesis of which we reported recently. In the considered azothiophenes, upon exposure to ultraviolet and visible radiation, we observed effective anti(trans) to syn(cis) and syn(cis) to anti(trans) isomerization of the -N[double bond, length as m-dash]N- moiety, respectively. In contrast to azobenzene based photo-switchable molecular systems, the syn(cis) to anti(trans) isomerization in the azothiophenes studied does not take place at 22 °C in the dark. Temperature dependent experiments and theoretical studies suggest a slightly higher barrier for such processes than for azobenzene, which we attribute to the specific structural and electronic properties of the thiophene ring and the nature of the side groups. We discuss the potential of the observed properties in the development of novel molecular photo-switching machinery to promote biocatalytic applications at interfaces.

10.
Chem Rev ; 118(22): 11118-11193, 2018 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-30362737

RESUMO

Metallo-oxide (MO)-based bioinorganic nanocomposites promise unique structures, physicochemical properties, and novel biochemical functionalities, and within the past decade, investment in research on materials such as ZnO, TiO2, SiO2, and GeO2 has significantly increased. Besides traditional approaches, the synthesis, shaping, structural patterning, and postprocessing chemical functionalization of the materials surface is inspired by strategies which mimic processes in nature. Would such materials deliver new technologies? Answering this question requires the merging of historical knowledge and current research from different fields of science. Practically, we need an effective defragmentation of the research area. From our perspective, the superficial accounting of material properties, chemistry of the surfaces, and the behavior of biomolecules next to such surfaces is a problem. This is particularly of concern when we wish to bridge between technologies in vitro and biotechnologies in vivo. Further, besides the potential practical technological efficiency and advantages such materials might exhibit, we have to consider the wider long-term implications of material stability and toxicity. In this contribution, we present a critical review of recent advances in the chemistry and engineering of MO-based biocomposites, highlighting the role of interactions at the interface and the techniques by which these can be studied. At the end of the article, we outline the challenges which hamper progress in research and extrapolate to developing and promising directions including additive manufacturing and synthetic biology that could benefit from molecular level understanding of interactions occurring between inanimate (abiotic) and living (biotic) materials.

11.
Adv Funct Mater ; 28(27)2018 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-30140193

RESUMO

Biomineralization at the organic-inorganic interface is critical to many biology material functions in vitro and in vivo. Recombinant silk-silica fusion peptides are organic-inorganic hybrid material systems that can be effectively used to study and control biologically-mediated mineralization due to the genetic basis of sequence control. However, to date, the mechanisms by which these functionalized silk-silica proteins trigger the differentiation of human mesenchymal stem cells (hMSCs) to osteoblasts remain unknown. To address this challenge, we analyzed silk-silica surfaces for silica-hMSC receptor binding and activation, and the intracellular pathways involved in the induction of osteogenesis on these bioengineered biomaterials. The induction of gene expression of αVß3 integrin, all three Mitogen-activated Protein Kinsases (MAPKs) as well as c-Jun, Runt-related Transcription Factor 2 (Runx2) and osteoblast marker genes was demonstrated upon growth of the hMSCs on the silk-silica materials. This induction of key markers of osteogenesis correlated with the content of silica on the materials. Moreover, computational simulations were performed for silk/silica-integrin binding which showed activation of αVß3 integrin in contact with silica. This integrated computational and experimental approach provides insight into interactions that regulate osteogenesis towards more efficient biomaterial designs.

12.
Langmuir ; 34(28): 8255-8263, 2018 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-29924624

RESUMO

In this contribution, the effect of silica particle size (28 and 210 nm) and surface chemistry (i.e., hydroxyl, methyl, or amino groups) on peptide binding response is studied with a specific emphasis on the effect of the extent of functionalization on binding. Exhaustive characterization of the silica surfaces was crucial for knowledge of the chemistry and topography of the solid surface under study and, thus, to understand their impact on adsorption and the conformational ensemble of the peptides. The extent of surface functionalization was shown to be particle-size dependent, a higher level of 3-aminopropyl functionality being obtained for smaller particles, whereas a higher degree of methyl group functionality was found for the larger particles. We demonstrated that peptide interactions at the aqueous interface were not only influenced by the surface chemistry but also by the extent of functionalization where a "switch" of peptide adsorption behavior was observed, whereas the changes in the conformational ensemble revealed by circular dichroism were independent of the extent of functionalization. In addition to electrostatic interactions and hydrogen bonding driving interaction at the silica-peptide interface, the data obtained suggested that stronger interactions such as hydrophobic and/or covalent interactions may moderate the interaction. The insights gained from this peptide-mineral study give a more comprehensive view of mechanisms concerning mineral-peptide interactions which may allow for the design and synthesis of novel (nano)materials with properties tailored for specific applications.


Assuntos
Peptídeos/metabolismo , Dióxido de Silício/metabolismo , Adsorção , Ligações de Hidrogênio , Peptídeos/química , Dióxido de Silício/química , Propriedades de Superfície
13.
J Phys Chem A ; 122(22): 4997-5003, 2018 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-29738240

RESUMO

Structural properties of bioinorganic composites are of current interest in the areas of drug delivery, bone repair, and biomimetics. In such composite systems, structural analysis is enhanced when we combine methods of spectroscopy and simulation. Depending on size and shape, structural discontinuities of inorganic matter may modulate the optical response of a bound molecule. Using density functional theory, we explore the effects of a local field next to the surface of a silica cluster on frequencies of methyl stretching modes of associated methanols. Computation results predict that the electrostatic potential modulated by structural discontinuities of silica should not contribute to any systematic frequency shifts for normal modes of a guest molecule. Regardless of position, the methyl stretching modes of methanol demonstrate sensitivity only to the local chemistry of bonding with silanols, which may lead either to a low or high frequency shift for vibrations. In support, experimental studies of deuterated methanol at impurity levels in water show uniform broadening of resonances of carbon-deuterium stretching modes in the presence of both crystalline and amorphous silica nanoparticles. The significance of these findings is that the spectral responses of guest molecules on such surfaces should not be subject to bias introduced by edge effects.

14.
Acta Biomater ; 73: 355-364, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29649640

RESUMO

The physical and mechanical properties of structural proteins such as silk fibroin can be modified by controlled conformational change, which is regularly monitored by Fourier transform infrared spectroscopy by peak fitting of the amide I band envelope. Although many variables affecting peak shape are well established, there is no fixed methodology to compare and follow secondary structural differences without significant operator input especially where low frequency spectral noise is a problem. The aim of this contribution is to establish a method for such analyses to be carried at high levels of autonomy to prevent subjective or erroneous fitting. A range of approaches was trialled with optimal peak parameters selected based on overall goodness of fit and reproducibility of fit of replicate sample spectra. The method was successfully tested against reference proteins having contrasting ß content and the rationale for parameter selection is presented. Further, we applied this method to measure the effect of conformational change on the energy of the amide I band of silk fibroin during annealing. Energy changes were ca. 400 kJ mol-1 of fibroin. To confirm that this energy change was a consequence of increased hydrogen bonding we used a Thioflavin T staining method typically used to identify ß aggregate type structures in amyloid plaques. We propose that the approach described herein can aid in the development of silk based materials for biomedical applications where tuning of the physical and mechanical properties of the silk are needed to guarantee optimum activity. STATEMENT OF SIGNIFICANCE: The physical and mechanical properties of proteins including silk fibroin can be modified by controlled structural change, which is regularly monitored by Fourier transform infrared spectroscopy (FTIR) by peak fitting of the amide I band. Currently there is no fixed methodology to compare and follow secondary structural differences without significant operator input leading to subjectivity and error. This contribution establishes a method for such analyses to be carried at high levels of autonomy applicable to a wide range of proteins and the conformational changes have been quantified as a single energy change output, which clearly shows the progression of the annealing process used. We propose that the approach can help in the development of silk based materials for biomedical applications where tuning of the physical and mechanical properties of the silk are needed to guarantee optimum activity.


Assuntos
Fibroínas/química , Estrutura Secundária de Proteína , Espectrofotometria/métodos , Amidas/química , Animais , Benzotiazóis/química , Materiais Biocompatíveis/química , Bombyx , Humanos , Distribuição Normal , Placa Amiloide/química , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier
15.
Colloids Surf B Biointerfaces ; 166: 195-202, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29597152

RESUMO

Porous silica-based materials are attractive for biomedical applications due to their biocompatibility and biodegradable character. In addition, inorganic supports such as porous silicon are being developed due to integrated circuit chip compatibility and tunable properties leading to a wide range of multidisciplinary applications. In this contribution, biosilica extracted from a rarely studied plant material (Equisetum Myriochaetum), its conversion to silicon and the potential for both materials to be used as supports for enzyme immobilization are investigated. E. myriochaetum was subject to conventional acid digestion to extract biogenic silica with a% yield remarkably higher (up to 3 times) than for other Equisetum sp. (i.e. E. Arvense). The surface area of the isolated silica was ∼400 m2/g, suitable for biotechnological applications. Biogenic silicon was obtained by magnesiothermic reduction. The materials were characterized by SEM-EDX, XRD, FT-IR, ICP-OES, TGA and BET analysis and did not contain significant levels of class 1 heavy elements (such as Pb, Cd, Hg and As). Two commercial peroxidases, horseradish peroxidase (HRP) and Coprinus cinereus peroxidase (CiP) were immobilized onto the biogenic materials using three different functionalization routes: (A) carbodiimide, (B) amine + glutaraldehyde and (C) amine + carbodiimide. Although both biogenic silica and porous silicon could be used as supports differences in behaviour were observed for the two enzymes. For HRP, loading onto biogenic silica via the glutaraldehyde immobilization technique (route B) was most effective. The loading of CiP showed a much higher peroxidase activity onto porous silicon than silica functionalized by the carbodiimide method (route A). From the properties of the extracted materials obtained from Equisetum Myriochaetum and the immobilization results observed, these materials appear to be promising for industrial and biomedical applications.


Assuntos
Enzimas Imobilizadas/química , Equisetum/química , Dióxido de Silício/química , Silício/química , Porosidade
16.
Plant Physiol Biochem ; 125: 205-211, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29475086

RESUMO

Siliceous frustules of diatom algae contain unique long-chain polyamines, including those having more than six nitrogen atoms. These polyamines participate in the formation of the siliceous frustules of the diatoms but their precise physiological role is not clear. The main hypotheses include formation of a polyamine and polyphosphate supramolecular matrix. We have synthesized novel fluorescent dyes from a synthetic oligomeric mixture of polyamines and the fluorophore 7-nitro-2,1,3-benzoxadiazole. The long polyamine chain ensures the high affinity of these dyes to silica, which allows their application in the staining of siliceous materials, such as valves of diatom algae and fossilized samples from sediments. The fluorescently stained diatom valves were found to be promising liquid flow tracers in hydrodynamic tests. Furthermore, complexation of the polyamine component of the dyes with carbonic polymeric acids results in changes to the visible spectrum of the fluorophore, which allows study of the stability of the complex vs the length of the polyamine chain. Using poly (vinyl phosphonic acid) as a model for phosphate functionality in silaffins (a potential matrix in the formation of biogenic silica) little complexation with the polyamine fluorophores was observed, bringing into question the role of a polyamine - polymeric phosphate matrix in biosilicification.


Assuntos
4-Cloro-7-nitrobenzofurazano/química , Poliaminas Biogênicas , Diatomáceas , Corantes Fluorescentes/química , Coloração e Rotulagem/métodos , Poliaminas Biogênicas/química , Poliaminas Biogênicas/metabolismo , Diatomáceas/citologia , Diatomáceas/metabolismo
17.
Sci Rep ; 7(1): 7681, 2017 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-28794471

RESUMO

We present a non-destructive analytical calibration tool to allow quantitative assessment of individual calcium phosphates such as hydroxyapatite (HAP) from mixtures including brushite. Many experimental approaches are used to evaluate the mineralising capabilities of biomolecules including peptides. However, it is difficult to quantitatively compare the efficacy of peptides in the promotion of mineralisation when inseparable mixtures of different minerals are produced. To address this challenge, a series of hydroxyapatite and brushite mixtures were produced as a percent/weight (0-100%) from pure components and multiple (N = 10) XRD patterns were collected for each mixture. A linear relationship between the ratio of selected peak heights and the molar ratio was found. Using this method, the mineralising capabilities of three known hydroxyapatite binding peptides, CaP(S) STLPIPHEFSRE, CaP(V) VTKHLNQISQSY and CaP(H) SVSVGMKPSPRP, was compared. All three directed mineralisation towards hydroxyapatite in a peptide concentration dependent manner. CaP(V) was most effective at inducing hydroxyapatite formation at higher reagent levels (Ca2+ = 200 mM), as also seen with peptide-silk chimeric materials, whereas CaP(S) was most effective when lower concentrations of calcium (20 mM) and phosphate were used. The approach can be extended to investigate HAP mineralisation in the presence of any number of mineralisation promoters or inhibitors.


Assuntos
Durapatita/química , Peptídeos/química , Oligoelementos/química , Calcificação Fisiológica , Durapatita/farmacologia , Estrutura Molecular , Peptídeos/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
18.
Acta Biomater ; 49: 127-139, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27940162

RESUMO

Protein polymers provide a unique opportunity for tunable designs of material systems due to the genetic basis of sequence control. To address the challenge of biomineralization interfaces with protein based materials, we genetically engineered spider silks to design organic-inorganic hybrid systems. The spider silk inspired domain (SGRGGLGGQG AGAAAAAGGA GQGGYGGLGSQGT)15 served as an organic scaffold to control material stability and to allow multiple modes of processing, whereas the hydroxyapatite binding domain VTKHLNQISQSY (VTK), provided control over osteogenesis. The VTK domain was fused either to the N-, C- or both terminals of the spider silk domain to understand the effect of position on material properties and mineralization. The addition of the VTK domain to silk did not affect the physical properties of the silk recombinant constructs, but it had a critical role in the induction of biomineralization. When the VTK domain was placed on both the C- and N-termini the formation of crystalline hydroxyapatite was significantly increased. In addition, all of the recombinant proteins in film format supported the growth and proliferation of human mesenchymal stem cells (hMSCs). Importantly, the presence of the VTK domain enhanced osteoinductive properties up to 3-fold compared to the control (silk alone without VTK). Therefore, silk-VTK fusion proteins have been shown suitable for mineralization and functionalization for specific biomedical applications. STATEMENT OF SIGNIFICANCE: Organic-inorganic interfaces are integral to biomaterial functions in many areas of repair and regeneration. Several protein polymers have been investigated for this purpose. Despite their success the limited options to fine-tune their material properties, degradation patterns and functionalize them for each specific biomedical application limits their application. Various studies have shown that the biological performance of such proteins can be improved by genetic engineering. The present study provides data relating protein design parameters and functional outcome quantified by biomineralization and human mesenchymal stem cell differentiation. As such, it helps the design of osteoinductive recombinant biomaterials for bone regeneration.


Assuntos
Regeneração Óssea/efeitos dos fármacos , Osseointegração/efeitos dos fármacos , Proteínas Recombinantes de Fusão/farmacologia , Seda/química , Materiais Biocompatíveis/farmacologia , Calcificação Fisiológica/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Imuno-Histoquímica , Sialoproteína de Ligação à Integrina/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Peptídeos/farmacologia , Proteínas Recombinantes de Fusão/química , Soluções , Eletricidade Estática , Difração de Raios X
19.
Recent Pat Nanotechnol ; 11(3): 168-180, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27915977

RESUMO

BACKGROUND: Although the popularity of using combinatorial display techniques for recognising unique peptides having high affinity for inorganic (nano) particles has grown rapidly, there are no systematic reviews showcasing current developments or patents on binding peptides specific to these materials. In this review, we summarize and discuss recent progress in patents on material binding peptides specifically exploring inorganic nano surfaces such as metals, metal oxides, minerals, carbonbased materials, polymer based materials, magnetic materials and semiconductors. We consider both the peptide display strategies used and the exploitation of the identified peptides in the generation of advanced nanomaterials. METHOD: In order to get a clear picture on the number of patents and literature present to date relevant to inorganic material binding biomolecules and their applications, a thorough online search was conducted using national and worldwide databases. The literature search include standard bibliographic databases while patents included EPO Espacenet, WIPO patent scope, USPTO, Google patent search, Patent lens, etc. along with commercial databases such as Derwent and Patbase. Both English and American spellings were included in the searches. RESULTS: The initial number of patents found related to material binders were 981. After reading and excluding irrelevant patents such as organic binding peptides, works published before 2001, repeated patents, documents not in English etc., 51 highly relevant patents published from 2001 onwards were selected and analysed. These patents were further separated into six categories based on their target inorganic material and combinatorial library used. They include relevant patents on metal, metal oxide or combination binding peptides (19), magnetic and semiconductor binding peptides (8), carbon based (3), mineral (5), polymer (8) and other binders (9). Further, how these material specific binders have been used to synthesize simple to complex bio- or nano-materials, mediate the controlled biomineralization process, direct self-assembly and nanofabrication of ordered structures, facilitate the immobilization of functional biomolecules and construct inorganic-inorganic or organic-inorganic nano hybrids are concisely described. CONCLUSION: From analysis of recent literature and patents, we clearly show that biomimetic material binders are in the vanguard of new design approaches for novel nanomaterials with improved/ controlled physical and chemical properties that have no adverse effect on the structural or functional activities of the nanomaterials themselves.

20.
Microsc Microanal ; 22(6): 1128-1145, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27784342

RESUMO

The article explores the theory of infrared-visible sum frequency generation microscopy of phospholipid envelopes with dimensions larger than the wavelength of the nonlinear emission. The main part of the study concerns derivation and accounting for the contributions of effective nonlinear responses specific to sites on the surfaces of a bilayer envelope and their dependence on polarization condition and experimental geometry. The nonlinear responses of sites are mapped onto the image plane according to their emission directions and the numerical aperture of a sampling microscope objective. According to the simulation results, we discuss possible approaches to characterize the shape of the envelope, to extract molecular hyperpolarizabilities, and to anticipate possible heterogeneity in envelope composition and anisotropy of the environment proximal to the envelope. The modeling approach offers a promising analytic facility to assist connecting microscopy observations in engineered liposomes, cellular envelopes, and subcellular organelles of relatively large dimensions to molecular properties, and hence to chemistry and structure down to available spatial resolution.


Assuntos
Processamento de Imagem Assistida por Computador , Raios Infravermelhos , Luz , Lipossomos/ultraestrutura , Microscopia , Modelos Biológicos , Membrana Celular/ultraestrutura
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