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1.
Se Pu ; 37(8): 845-852, 2019 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642255

RESUMO

The study of protein glycosylation is important to deepening the current understanding of its biological functions as well as to elucidate novel biomarkers of glycosylation. However, glycopeptides must be enriched prior to analysis due to their naturally low abundance. In this study, tryptophan functionalized polymer materials (denoted as Poly-Trp) were synthesized to serve as a novel biomimetic polymers. The resulting materials were characterized by various methods including scanning electron microscopy, thermal analysis, and infrared spectrometry, validating the successful synthesis of Poly-Trp. The retention of glycopeptides on Poly-Trp was investigated revealing that the retention ability decreased as the acetonitrile content of the mobile phase decreased and its acidity increased. Poly-Trp exhibited higher enrichment selectivity for glycopeptides from bovine fetuin than the commercial material ZIC-HILIC, and aminated silica which could defect the interference of 100-fold amount of substance ratios of bovine serum albumin. Poly-Trp is expected to have further applications in the purification of biological samples for the study of glycosylation.


Assuntos
Biomimética , Glicopeptídeos/química , Polímeros/química , Animais , Bovinos , Fetuínas/química , Glicosilação , Dióxido de Silício
2.
J Chromatogr A ; 1604: 460474, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31493850

RESUMO

Biomimetic affinity chromatography with short peptide ligands is a developing technology, which has great potential for antibody separation and purification. In this study, a tetrapeptide library with critical residues of natural ligands to hIgG was constructed and a novel tetrapeptide ligand (Ac-FYHE) with high LibDock scores was selected by molecular docking. Then, Ac-FYHE ligand was linked to agarose bead to prepare a new chromatography resin. The properties of antibody adsorption were measured and evaluated by static/dynamic adsorption. It was found that the resin with ligand Ac-FYHE has high binding capacity and selectivity for hIgG. The results showed the Qm-hIgG of Ac-FYHE-4FF resin was 87.9 mg/g resin while the Qm-BSA of this resin was only 16.5 mg/g resin at pH 7.0. Moreover, at pH 7.0, Q10% of Ac-FYHE-4FF resin was 24.1 mg/mL for hIgG but just 2.1 mg/mL for BSA, which presented high selectivity of the screened resin at pH 7.0. Subsequently, the adsorption and separation properties of the Ac-FYHE-4FF resin were further investigated. As a result, with the addition of 0.5 M NaCl, Qm decreased by less than 20% but Qm decreased by 70% with the addition of 50% (v/v) ethylene glycol, which indicated that hydrophobic interaction would be the driving force for the binding between resin and hIgG. Besides, pH 7.5 and pH 4.5 could be the optimal loading and elution condition for hIgG, respectively. Finally, the Ac-FYHE-4FF resin was applied to separate mAb or/and hIgG from BSA containing feedstock, CHO cell culture supernatant and human serum, and the purity and recovery were both more than 90% with only one-step separation. The results indicate that the Ac-FYHE-4FF resin developed in this work would be promising for antibody separation and purification.


Assuntos
Anticorpos/isolamento & purificação , Biomimética , Técnicas de Química Analítica/métodos , Cromatografia de Afinidade , Adsorção , Animais , Células CHO , Cricetinae , Cricetulus , Humanos , Interações Hidrofóbicas e Hidrofílicas , Ligantes , Simulação de Acoplamento Molecular , Peptídeos/química , Sefarose/química
3.
Chem Commun (Camb) ; 55(66): 9865-9868, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31364624

RESUMO

Au hydrogel with a well-defined nanowire network was rationally designed through one-step dopamine-induced self-assembly. Due to the porous nanostructure along with the polydopamine induced accumulation and interfacial electron transfer effects, the resulting Au hydrogel nanozyme exhibits enhanced glucose oxidase-like activity and peroxidase-like activity, with a biomimetic cascade catalysis.


Assuntos
Biomimética , Dopamina/química , Glucose Oxidase/química , Ouro/química , Hidrogéis/química , Nanopartículas Metálicas/química , Peroxidase/química , Catálise , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Oxirredução
4.
Chem Commun (Camb) ; 55(70): 10444-10447, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31410430

RESUMO

A new series of 2D catalytic materials whose inorganic surfaces are fully covered with pre-designed "promoter" groups are reported. One of them showed excellent biomimetic catalytic activity and provided the lowest detection limit to glucose among the reported 2D materials and their composite materials.


Assuntos
Biomimética , Calcogênios/química , Metais/química , Catálise , Limite de Detecção , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Espectroscopia Fotoeletrônica , Difração de Pó
5.
Phys Chem Chem Phys ; 21(41): 22711-22721, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31454001

RESUMO

Peptide appended pillar[5]arene (PAP) is an artificial water channel resembling biological water channel proteins, which has shown a significant potential for designing bioinspired water purification systems. Given that PAP channels need to be incorporated at a high density in membrane matrices, it is critical to examine the role of channel-channel and channel-membrane interactions in governing the structural and functional characteristics of channels. To resolve the atomic-scale details of these interactions, we have carried out atomistic molecular dynamics (MD) simulations of multiple PAP channels inserted in a lipid or a block-copolymer (BCP) membrane matrix. Classical MD simulations on a sub-microsecond timescale showed clustering of channels only in the lipid membrane, but enhanced sampling MD simulations showed thermodynamically-favorable dimerized states of channels in both lipid and BCP membranes. The dimerized configurations of channels, with an extensive buried surface area, were stabilized via interactions between the aromatic groups in the peptide arms of neighboring channels. The conformational metrics characterizing the orientational and structural changes in channels revealed a higher flexibility in the lipid membrane as opposed to the BCP membrane although hydrogen bonds between the channel and the membrane molecules were not a major contributor to the stability of channels in the BCP membrane. We also found that the channels undergo wetting/dewetting transitions in both lipid and BCP membranes with a marginally higher probability of undergoing a dewetting transition in the BCP membrane. Collectively, these results highlight the role of channel dynamics in governing channel-channel and channel-membrane interfacial interactions, and provide atomic-scale insights needed to design stable and functional biomimetic membranes for efficient separations.


Assuntos
Aquaporinas/química , Calixarenos/química , Membrana Celular/química , Aquaporinas/metabolismo , Biomimética , Membrana Celular/metabolismo , Modelos Moleculares , Conformação Molecular , Simulação de Dinâmica Molecular
6.
Phys Life Rev ; 29: 51-54, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31307950

RESUMO

We look at a recent expansion of Physarum research from inspiring biomimetic algorithms to serving as a model organism in the evolutionary study of perception, memory, learning, and decision making.


Assuntos
Physarum , Algoritmos , Biomimética , Resolução de Problemas , Inquéritos e Questionários
7.
Chem Commun (Camb) ; 55(65): 9649-9652, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31339160

RESUMO

Intracellular delivery of bioactive polyphenols is currently evaluated as a protective strategy for cells under pharmaceutical stress. To this end, the 20mer R5 peptide from the marine diatom C. fusiformis was N-terminally modified with a quercetin derivative. This polyphenol-peptide conjugate was used to generate homogeneous silica particles under biomimetic conditions that are efficiently taken up by eukaryotic cells without being cytotoxic. However, not only was accumulation in the cytoplasm of living cells observed via electron and fluorescence microscopy but also translocation into the nucleus. The latter was only seen when the quercetin-peptide conjugate was present within the silica particles and provides a novel targeting option for silica particles to nuclei.


Assuntos
Núcleo Celular/metabolismo , Corantes Fluorescentes/farmacocinética , Fragmentos de Peptídeos/farmacocinética , Quercetina/análogos & derivados , Quercetina/farmacocinética , Dióxido de Silício/farmacocinética , Transporte Ativo do Núcleo Celular , Biomimética , Diatomáceas/química , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Corantes Fluorescentes/toxicidade , Células HT29 , Humanos , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/toxicidade , Quercetina/síntese química , Quercetina/toxicidade , Dióxido de Silício/química , Dióxido de Silício/toxicidade
8.
Nature ; 571(7765): 381-386, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31292552

RESUMO

In ant colonies, collectivity enables division of labour and resources1-3 with great scalability. Beyond their intricate social behaviours, individuals of the genus Odontomachus4, also known as trap-jaw ants, have developed remarkable multi-locomotion mechanisms to 'escape-jump' upwards when threatened, using the sudden snapping of their mandibles5, and to negotiate obstacles by leaping forwards using their legs6. Emulating such diverse insect biomechanics and studying collective behaviours in a variety of environments may lead to the development of multi-locomotion robotic collectives deployable in situations such as emergency relief, exploration and monitoring7; however, reproducing these abilities in small-scale robotic systems with simple design and scalability remains a key challenge. Existing robotic collectives8-12 are confined to two-dimensional surfaces owing to limited locomotion, and individual multi-locomotion robots13-17 are difficult to scale up to large groups owing to the increased complexity, size and cost of hardware designs, which hinder mass production. Here we demonstrate an autonomous multi-locomotion insect-scale robot (millirobot) inspired by trap-jaw ants that addresses the design and scalability challenges of small-scale terrestrial robots. The robot's compact locomotion mechanism is constructed with minimal components and assembly steps, has tunable power requirements, and realizes five distinct gaits: vertical jumping for height, horizontal jumping for distance, somersault jumping to clear obstacles, walking on textured terrain and crawling on flat surfaces. The untethered, battery-powered millirobot can selectively switch gaits to traverse diverse terrain types, and groups of millirobots can operate collectively to manipulate objects and overcome obstacles. We constructed the ten-gram palm-sized prototype-the smallest and lightest self-contained multi-locomotion robot reported so far-by folding a quasi-two-dimensional metamaterial18 sandwich formed of easily integrated mechanical, material and electronic layers, which will enable assembly-free mass-manufacturing of robots with high task efficiency, flexibility and disposability.


Assuntos
Formigas/anatomia & histologia , Formigas/fisiologia , Biomimética , Locomoção , Movimento , Robótica/instrumentação , Robótica/métodos , Animais , Marcha
9.
Adv Exp Med Biol ; 1140: 13-43, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31317494

RESUMO

The most widely-used assays for studying viral entry, including infectivity, cofloatation, and cell-cell fusion assays, yield functional information but provide low resolution of individual entry steps. Structural characterization provides high-resolution conformational information, but on its own is unable to address the functional significance of these conformations. Single virion tracking microscopy techniques provide more detail on the intermediate entry steps than infection assays and more functional information than structural methods, bridging the gap between these methods. In addition, single virion approaches also provide dynamic information about the kinetics of entry processes. This chapter reviews single virion tracking techniques and describes how they can be applied to study specific virus entry steps. These techniques provide information complementary to traditional ensemble approaches. Single virion techniques may either probe virion behavior in live cells or in biomimetic platforms. Synthesizing information from ensemble, structural, and single virion techniques ultimately yields a more complete understanding of the viral entry process than can be achieved by any single method alone.


Assuntos
Biomimética , Células , Microscopia , Internalização do Vírus , Células/virologia , Virologia/instrumentação
10.
Philos Trans A Math Phys Eng Sci ; 377(2150): 20190118, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31177953

RESUMO

Cacti use the Laplace pressure gradient due to conical geometry as a mechanism for collecting water from fog. Bioinspired surfaces using conical geometry can be developed for water collection from fog for human consumption. A systematic study is presented which investigates the dynamics of water droplets on a bioinspired conical surface. A series of experiments was conducted where a known volume of droplets was deposited on the cone. This was followed by an investigation into droplet dynamics where the droplets are deposited from fog and the volume is unknown. This includes a study on the macroscopic level as well as the microscopic level. The main parameters that were varied for these tests were the tip angle and the cone orientation. The droplet movement observed was compared relatively. Based on captured videos of droplet movement, distance travelled and velocities were measured. The Laplace pressure gradient, gravity and droplet coalescence were found to be the mechanisms of droplet movement on a conical surface. The findings of this study should be of interest in designing bioinspired surfaces with high water collection. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 2)'.


Assuntos
Biomimética , Água Potável , Propriedades de Superfície , Abastecimento de Água , Água , Tempo (Meteorologia) , Cactaceae/anatomia & histologia , Água/química , Abastecimento de Água/métodos , Molhabilidade
11.
Retrovirology ; 16(1): 13, 2019 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-31036006

RESUMO

BACKGROUND: HIV-1 patients receiving combination antiretroviral therapy (cART) survive infection but require life-long adherence at high expense. In chronic cART-treated patients with undetectable viral titers, cell-associated viral RNA is still detectable, pointing to low-level viral transcriptional leakiness. To date, there are no FDA-approved drugs against HIV-1 transcription. We have previously shown that F07#13, a third generation Tat peptide mimetic with competitive activity against Cdk9/T1-Tat binding sites, inhibits HIV-1 transcription in vitro and in vivo. RESULTS: Here, we demonstrate that increasing concentrations of F07#13 (0.01, 0.1, 1 µM) cause a decrease in Tat levels in a dose-dependent manner by inhibiting the Cdk9/T1-Tat complex formation and subsequent ubiquitin-mediated Tat sequestration and degradation. Our data indicate that complexes I and IV contain distinct patterns of ubiquitinated Tat and that transcriptional inhibition induced by F07#13 causes an overall reduction in Tat levels. This reduction may be triggered by F07#13 but ultimately is mediated by TAR-gag viral RNAs that bind suppressive transcription factors (similar to 7SK, NRON, HOTAIR, and Xist lncRNAs) to enhance transcriptional gene silencing and latency. These RNAs complex with PRC2, Sin3A, and Cul4B, resulting in epigenetic modifications. Finally, we observed an F07#13-mediated decrease of viral burden by targeting the R region of the long terminal repeat (HIV-1 promoter region, LTR), promoting both paused polymerases and increased efficiency of CRISPR/Cas9 editing in infected cells. This implies that gene editing may be best performed under a repressed transcriptional state. CONCLUSIONS: Collectively, our results indicate that F07#13, which can terminate RNA Polymerase II at distinct sites, can generate scaffold RNAs, which may assemble into specific sets of "RNA Machines" that contribute to gene regulation. It remains to be seen whether these effects can also be seen in various clades that have varying promoter strength, mutant LTRs, and in patient samples.


Assuntos
Regulação Viral da Expressão Gênica/efeitos dos fármacos , HIV-1/genética , RNA não Traduzido/genética , Transcrição Genética , Antirretrovirais/farmacologia , Biomimética , Sistemas CRISPR-Cas , Linhagem Celular , Edição de Genes , Inativação Gênica , HIV-1/efeitos dos fármacos , Humanos , Regiões Promotoras Genéticas , RNA Viral/genética , Produtos do Gene tat do Vírus da Imunodeficiência Humana/química
12.
Nature ; 569(7755): 208-214, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31068721

RESUMO

Software implementations of brain-inspired computing underlie many important computational tasks, from image processing to speech recognition, artificial intelligence and deep learning applications. Yet, unlike real neural tissue, traditional computing architectures physically separate the core computing functions of memory and processing, making fast, efficient and low-energy computing difficult to achieve. To overcome such limitations, an attractive alternative is to design hardware that mimics neurons and synapses. Such hardware, when connected in networks or neuromorphic systems, processes information in a way more analogous to brains. Here we present an all-optical version of such a neurosynaptic system, capable of supervised and unsupervised learning. We exploit wavelength division multiplexing techniques to implement a scalable circuit architecture for photonic neural networks, successfully demonstrating pattern recognition directly in the optical domain. Such photonic neurosynaptic networks promise access to the high speed and high bandwidth inherent to optical systems, thus enabling the direct processing of optical telecommunication and visual data.


Assuntos
Biomimética/métodos , Modelos Neurológicos , Redes Neurais (Computação) , Reconhecimento Automatizado de Padrão/métodos , Fótons , Aprendizado de Máquina Supervisionado , Aprendizado de Máquina não Supervisionado , Potenciais de Ação , Sistemas de Computação , Computadores , Rede Nervosa/citologia , Rede Nervosa/fisiologia , Neurônios/citologia , Neurônios/fisiologia , Sinapses/fisiologia
13.
Biosens Bioelectron ; 136: 97-105, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31048213

RESUMO

We report on a novel biomimetic sensor that allows sensitive and specific detection of Escherichia coli (E. coli) bacteria in a broad concentration range from 102 up to 106 CFU/mL in both buffer fluids and relevant food samples (i.e. apple juice). The receptors are surface-imprinted polyurethane layers deposited on stainless-steel chips. Regarding the transducer principle, the sensor measures the increase in thermal resistance between the chip and the liquid due to the presence of bacteria captured on the receptor surface. The low noise level that enables the low detection limit originates from a planar meander element that serves as both a heater and a temperature sensor. Furthermore, the experiments show that the presence of bacteria in a liquid enhances the thermal conductivity of the liquid itself. Reference tests with a set of other representative species of Enterobacteriaceae, closely related to E. coli, indicate a very low cross-sensitivity with a sensor response at or below the noise level.


Assuntos
Técnicas Bacteriológicas/métodos , Técnicas Biossensoriais/métodos , Escherichia coli/isolamento & purificação , Microbiologia de Alimentos , Biomimética
14.
J Biomed Nanotechnol ; 15(6): 1267-1279, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31072434

RESUMO

An ideal wound dressing should not only promote rapid hemostasis and wound healing but also have good biocompatibility, antimicrobial activities, and should mimic the skin's physiological function. In the present study, five O-quaternized chitosan (QAS-CS) materials with satisfactory antibacterial activity and no cytotoxicity were successfully synthesized. Furthermore, we reported the synthesis and characterization of the two novel composite nanofibrous scaffolds consisting of selfdeveloped collagen (COL), quaternary ammonium salt (QAS) or QAS-CS and polycaprolactone (PCL) or polyvinyl alcohol (PVA) with an electrospinning approach. The PCL/COL/QAS (PCQ3) and PVA/COL/QAS-CS (PCQC5) materials exhibited uniform, three-dimensional interconnected pore structure, high porosity, and large specific surface area, which can mimic the architecture and biological functions of the native extracellular matrix microenvironment and provide suitable conditions for cell adhesion, proliferation, and differentiation. The growth and proliferation of human immortalized epidermal (HaCaT) cells on PCQ3 and PCQC5 materials was good, and the result of blood compatibility and the skin irritant test indicated that the scaffolds had good blood compatibility and did not exhibit significant irritability. Importantly, PCQ3 and PCQC5 have notable effects on rapid hemostasis, antibacterial activity, and anti-inflammation, promote wound healing, and display other superior benefits in comparison to available products. Overall, PCQ3 and PCQC5 are proposed to be good candidates for skin tissue engineering applications and can be used on different types of wounds.


Assuntos
Hemostáticos , Nanofibras , Antibacterianos , Biomimética , Hemostasia , Humanos , Tecidos Suporte , Cicatrização
15.
Nat Commun ; 10(1): 2168, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-31092830

RESUMO

Adult cardiac tissue undergoes a rapid process of dedifferentiation when cultured outside the body. The in vivo environment, particularly constant electromechanical stimulation, is fundamental to the regulation of cardiac structure and function. We investigated the role of electromechanical stimulation in preventing culture-induced dedifferentiation of adult cardiac tissue using rat, rabbit and human heart failure myocardial slices. Here we report that the application of a preload equivalent to sarcomere length (SL) = 2.2 µm is optimal for the maintenance of rat myocardial slice structural, functional and transcriptional properties at 24 h. Gene sets associated with the preservation of structure and function are activated, while gene sets involved in dedifferentiation are suppressed. The maximum contractility of human heart failure myocardial slices at 24 h is also optimally maintained at SL = 2.2 µm. Rabbit myocardial slices cultured at SL = 2.2 µm remain stable for 5 days. This approach substantially prolongs the culture of adult cardiac tissue in vitro.


Assuntos
Insuficiência Cardíaca/patologia , Coração/fisiologia , Contração Miocárdica/fisiologia , Miocárdio/patologia , Técnicas de Cultura de Tecidos/métodos , Adulto , Animais , Biomimética/métodos , Humanos , Masculino , Microscopia Eletrônica de Transmissão , Miocárdio/citologia , Miocárdio/ultraestrutura , Coelhos , Ratos , Ratos Sprague-Dawley , Sarcômeros/fisiologia
16.
ACS Appl Mater Interfaces ; 11(17): 15262-15275, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30964624

RESUMO

Nanoparticles camouflaged by red blood cell (RBC) membranes have attracted considerable attention owing to reservation of structure of membrane and surface proteins, endowing prominent cell-specific function including biocompatibility, prolonged circulation lifetime, and reduced reticular endothelial system (RES) uptake ability. Considering the drawbacks of carrier-free nanomedicine including the serious drug burst release, poor stability, and lack of immune escape function, herein we developed and fabricated a novel RBC membranes biomimetic combinational therapeutic system by enveloping the small molecular drug coassemblies of 10-hydroxycamptothecin (10-HCPT) and indocyanine green (ICG) in the RBC membranes for prolonged circulation, controlled drug release, and synergistic chemo-photothermal therapy (PTT). The self-reorganized RBCs@ICG-HCPT nanoparticles (NPs) exhibited a diameter of ∼150 nm with core-shell structure, high drug payload (∼92 wt %), and reduced RES uptake function. Taking advantage of the stealth functionality of RBC membranes, RBCs@ICG-HCPT NPs remarkably enhanced the accumulation at the tumor sites by passive targeting followed by cellular endocytosis. Upon the stimuli of near-infrared laser followed by acidic stimulation, RBCs@ICG-HCPT NPs showed exceptional instability by heat-mediated membrane disruption and pH change, thereby triggering the rapid disassembly and accelerated drug release. Consequently, compared with individual treatment, RBCs@ICG-HCPT NPs under dual-stimuli accomplished highly efficient apoptosis in cancer cells and remarkable ablation of tumors by chemo-PTT. This biomimetic nanoplatform based on carrier-free, small molecular drug coassemblies integrating imaging capacity as a promising theranostic system provides potential for cancer diagnosis and combinational therapy.


Assuntos
Antineoplásicos Fitogênicos/química , Biomimética , Camptotecina/análogos & derivados , Membrana Celular/química , Raios Infravermelhos , Nanopartículas/química , Neoplasias/terapia , Animais , Antineoplásicos Fitogênicos/farmacologia , Antineoplásicos Fitogênicos/uso terapêutico , Apoptose/efeitos dos fármacos , Camptotecina/química , Camptotecina/farmacologia , Camptotecina/uso terapêutico , Eritrócitos/citologia , Eritrócitos/metabolismo , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Verde de Indocianina/química , Masculino , Camundongos , Camundongos Nus , Nanopartículas/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Fototerapia , Ratos , Ratos Sprague-Dawley
17.
Biomed Res Int ; 2019: 7127869, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31032360

RESUMO

Natural enzyme mimics have attracted considerable attention due to leakage of enzymes and their easy denaturation during their storage and immobilization procedure. Here in this study, for the first time, a new iron oxide hydroxide, ferrihydrite - Fe1.44O0.32 (OH) 3.68 magnetic nanoparticles were synthesized by bacterial strain named Comamonas testosteroni. The characterization of the produced magnetic nanoparticles was confirmed by transmission electron microscopy (TEM), Fourier-transform spectroscopy (FTIR), X-ray diffraction (XRD), and magnetization hysteresis loops. Further, these extracted nanoparticles were proven to have biogenic magnetic behavior and to exhibit enhanced peroxidase-like activity. It is capable of catalyzing the oxidation of 3, 3', 5, 5'-Tetramethylbenzidine (TMB) by H2O2 to produce blue color (typical color reactions). Catalysis was examined to follow Michaelis-Menton kinetics and the good affinity to both H2O2 and TMB. The K m value of the Fe1.44O0.32 (OH) 3.68 with H2O2 and TMB as the substrate was 0.0775 and 0.0155 mM, respectively, which were lower than that of the natural enzyme (HRP). Experiments of electron spin resonance (ESR) spectroscopy proved that the BMNPs could catalyze H2O2 to produce hydroxyl radicals. As a new peroxidase mimetic, the BMNPs were exhibited to offer a simple, sensitive, and selective colorimetric method for determination of H2O2 and glucose and efficiently catalyze the detection of glucose in real blood samples.


Assuntos
Comamonas testosteroni/química , Glucose/química , Peróxido de Hidrogênio/química , Peroxidase/química , Benzidinas/química , Biomimética , Técnicas Biossensoriais , Catálise , Espectroscopia de Ressonância de Spin Eletrônica , Compostos Férricos/síntese química , Compostos Férricos/química , Compostos Férricos/farmacologia , Glucose/isolamento & purificação , Peróxido de Hidrogênio/isolamento & purificação , Cinética , Nanopartículas de Magnetita , Microscopia Eletrônica de Transmissão , Oxirredução/efeitos dos fármacos , Peroxidase/síntese química , Peroxidase/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 217: 197-205, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30939366

RESUMO

Molecular switches are valuable tools for the detection of many chemical and biological processes. On the other hand, Schiff bases are known for their simplicity in synthesis and their enormous biochemical applications. In this scenario, when a strategically designed Schiff base acts as a molecular switch in biomimetic environments drags inevitable attention. In this article, we hereby demonstrate an interesting behavior of a strategically designed bioactive benzothiazole based Schiff base (E)-2-(((6-chlorobenzo[d]thiazol-2-ylimino)methyl)-5-diethylamino) phenol (CBMDP) whose fluorescence characteristics dramatically modulate as consequence of its structural modification in aqueous and biomimetic environments individually. Electronic absorption, steady state and time resolved fluorescence spectroscopic techniques along with DFT based quantum chemical calculation evidence that in pure organic solvents CBMDP exists in highly fluorescent enol-imine (N) form which transform into feebly fluorescent hydrated species (H) in bulk aqueous media. Contrariwise, on interaction with the ionic and non-ionic micellar media or with liposome, a structural restoration occurs from less fluorescent hydrated (H) species into a highly fluorescent normal (N) one. This molecular flipping of the title compound upon micellar compartmentalization is possibly caused by the micropolarity of the local environment and further supported by its spectral behavior in different polarity gradient solvent mixture of water-dioxane (protic-aprotic) and water-methanol (protic -protic). Usually, Schiff bases are prone to hydrolysis in aqueous media, interestingly, the structural framework of this strategically designed molecule only allow the first step of hydrolysis, which is hydration of azomethine linkage whereas it withstand the second step, and that possibly helps the structural restoration process. Hence the article described herein may emphasize how a systematically designed Schiff base framework can be used as 'turn off- turn on' fluorescent molecular switch which may be extremely useful for its applications in the area of biochemical sensors.


Assuntos
Benzotiazóis/química , Biomimética , Fluorescência , Teoria Quântica , Bases de Schiff/química , Solventes/química , Espectrometria de Fluorescência , Termodinâmica
19.
Mater Sci Eng C Mater Biol Appl ; 100: 915-927, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30948128

RESUMO

The nepenthes-inspired slippery liquid-infused surface has led to multiple potentials in biomedical devices' design. This study aims to develop a biomimetic, environmentally-friendly slippery layer of oil-infused 3D printed polydimethylsiloxane with anti-bacterial nanosilver (iPDMS/AgNPs) for wound dressing. The engineered 3D printed iPDMS can cater the different requirements of wounds with antifouling, anti-blood staining, and kill bacteria. iPDMS/AgNPs not only exhibits biocompatibility, against adherence and effective antibacterial activity but also effectively promotes neo-epithelial and granulation tissue formation to accelerate wound healing in vivo. Optimized rheologic parameters were obtained for the 3D printable iPDMS pre-polymerization condition. Scanning electronic micrograph (SEM) and Energy Dispersive Spectrometer (EDS) show a uniform mesh with AgNPs dotted on the printed dressing. No cytotoxicity of iPDMS/AgNPs has been found via cell Counting Kit-8(CCK-8) assay. Meanwhile, the membranes infused with silicon oil effectively prevented from the adherence of the two standard drug-resistant bacteria, Staphylococcus aureus and Escherichia coli (PDMS vs. PDMS+oil, p < 0.05; PDMS+0.5%AgNPs vs. iPDMS+0.5%AgNPs, p < 0.05; PDMS+2.5%AgNPs vs. iPDMS+2.5%AgNPs, p < 0.05). By bacteria co-culture model iPDMS/AgNPs can kill about 80% of Staphylococcus aureus and Escherichia coli. When applied to a full-thickness wound defect model of murine, iPDMS/AgNPs was effective in anti-infection. It also promotes the epithelialization, the granulation tissue formation, and wound healing. These findings demonstrate that iPDMS/AgNPs may have therapeutic promise as an ideal wound dressing shortly.


Assuntos
Antibacterianos/uso terapêutico , Incrustação Biológica , Biomimética , Dimetilpolisiloxanos/farmacologia , Óleos/química , Impressão Tridimensional , Cicatrização/efeitos dos fármacos , Infecção dos Ferimentos/tratamento farmacológico , Animais , Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Escherichia coli/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Tecido de Granulação/efeitos dos fármacos , Tecido de Granulação/patologia , Íons , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Nanocompostos/química , Nanocompostos/ultraestrutura , Reologia , Prata/química , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Temperatura Ambiente , Infecção dos Ferimentos/patologia
20.
Int J Pharm ; 563: 314-323, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30978483

RESUMO

Nanoparticles such as liposomes have been applied for the treatment of various diseases such as cancer and inflammatory diseases by utilizing the enhanced permeability and retention effect. However, their entry into inflammation sites is still limited since passive delivery of nanoparticles is often hampered by the presence of endothelial barriers. As leukocytes can pass through the inflamed endothelium via utilizing membrane protein functions, we hypothesized that incorporating leukocyte membrane proteins onto liposomal membranes may impart leukocyte-mimicking functions to liposomes, allowing for their adherence to and active passage through the inflamed endothelium. Herein, we developed leukocyte-mimetic liposomes (LM-Lipo) by leukocyte membrane protein transfer and evaluated their function in vitro. Transfer of membrane proteins from human leukemia cells onto liposomal membranes allowed for significant association of the liposomes with inflamed human endothelial cells, and subsequent passage through inflamed endothelial cell layer. The confocal images showed that LM-Lipo significantly induced vascular endothelial-cadherin displacement. These results indicate that LM-Lipo adhered to and regulated intercellular junctions of inflamed endothelial cell layer, resulting in passage through the layer, by mimicking the function of leukocytes. Furthermore, it is suggested that liposomes possessing leukocyte-like functions could be useful for drug delivery to inflammation sites by overcoming endothelial barriers.


Assuntos
Células Endoteliais da Veia Umbilical Humana/metabolismo , Junções Intercelulares/metabolismo , Leucócitos , Lipossomos/administração & dosagem , Proteínas de Membrana/administração & dosagem , Biomimética , Células HL-60 , Humanos , Inflamação/metabolismo
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