Carbon nanofiber modified with osmium based redox polymer for glucose sensing

Electrochemical detection of glucose was performed on carbon nanofibers containing an osmium based redox polymer and using glucose oxidase enzyme. Redox polymer assembled on the nanofibers provided a more stable support that preserved enzyme activity and promoted the electrical communication to the glassy carbon electrode. The morphologies, structures, and electrochemical behavior of the redox polymer modified nanofibers were characterized by scanning electron microscope, energy dispersive spectrometer and voltammetry. The glucose oxidase showed excellent communication with redox polymer as observed with the increased activity toward glucose. Both cyclic voltammetry and amperometry showed a linear response with glucose concentration. The linear range for glucose determination was from 1 to 12 mM with a relatively high sensitivity of 0.20±0.01 μA mM−1 for glucose oxidase in carbon nanofibers and 0.10±0.01 μA mM−1 without carbon nanofibers. The apparent Michaelis–Menten constant (Km) for glucose oxidase with carbon nanofibers was 0.99 mM. On the other hand, the Km value for the glucose oxidase without the nanofibers was 4.90 mM

Biomolecular Triconjugates Formed between Gold, Protamine, and Nucleic Acid: Comparative Characterization on the Nanoscale

DNA and RNA micro- and nanoparticles are increasingly being used for gene and siRNA drug delivery and a variety of other applications in bionanotechnology. On the nanoscale, these entities represent unique challenges from a physicochemical characterization perspective. Here, nucleic acid conjugates with protamine and gold nanoparticles (GNP) were characterized comparatively in the nanorange of concentration by UV/Vis NanoDrop spectroscopy, fluorimetry, and gel electrophoresis. Given the intense interest in splice-site switching oligomers (SSOs), we utilized a human tumor cell culture system (HeLa pLuc-705), in which SSO-directed splicing repair upregulates luciferase expression, in order to investigate bioactivity of the bionanoconjugates. Process parameters important for bioactivity were investigated, and the bimolecular nanoconjugates were confirmed by shifts in the dynamic laser light scatter (DLLS), UV/Vis spectrum, gel electrophoresis, or sedimentation pattern. The data presented herein may be useful in the future development of pharmaceutical and biotechnology formulations, processes, and analyses concerning protein, DNA, or RNA bionanoconjugates

Control of Neural Stem Cell Survival by Electroactive Polymer Substrates

Stem cell function is regulated by intrinsic as well as microenvironmental factors, including chemical and mechanical signals. Conducting polymer-based cell culture substrates provide a powerful tool to control both chemical and physical stimuli sensed by stem cells. Here we show that polypyrrole (PPy), a commonly used conducting polymer, can be tailored to modulate survival and maintenance of rat fetal neural stem cells (NSCs). NSCs cultured on PPy substrates containing different counter ions, dodecylbenzenesulfonate (DBS), tosylate (TsO), perchlorate (ClO4) and chloride (Cl), showed a distinct correlation between PPy counter ion and cell viability. Specifically, NSC viability was high on PPy(DBS) but low on PPy containing TsO, ClO4 and Cl. On PPy(DBS), NSC proliferation and differentiation was comparable to standard NSC culture on tissue culture polystyrene. Electrical reduction of PPy(DBS) created a switch for neural stem cell viability, with widespread cell death upon polymer reduction. Coating the PPy(DBS) films with a gel layer composed of a basement membrane matrix efficiently prevented loss of cell viability upon polymer reduction. Here we have defined conditions for the biocompatibility of PPy substrates with NSC culture, critical for the development of devices based on conducting polymers interfacing with NSCs

An Effective Amperometric Biosensor Based on Gold Nanoelectrode Arrays

A sensitive amperometric biosensor based on gold nanoelectrode array (NEA) was investigated. The gold nanoelectrode array was fabricated by template-assisted electrodeposition on general electrodes, which shows an ordered well-defined 3D structure of nanowires. The sensitivity of the gold NEA to hydrogen peroxide is 37 times higher than that of the conventional electrode. The linear range of the platinum NEA toward H2O2is from 1 × 10−6to 1 × 10−2 M, covering four orders of magnitudes with detection limit of 1 × 10−7 M and a single noise ratio (S/N) of four. The enzyme electrode exhibits an excellent response performance to glucose with linear range from 1 × 10−5to 1 × 10−2 M and a fast response time within 8 s. The Michaelis–Menten constantkm and the maximum current densityimaxof the enzyme electrode were 4.97 mM and 84.60 μA cm−2, respectively. This special nanoelectrode may find potential application in other biosensors based on amperometric signals

“Convento de Nossa Senhora dos Remédios – Reutilização Museológica de um Património Conventual”.

Resumo: Pretende-se fazer a abordagem de um conjunto conventual que passou por vicissitudes várias desde a sua desocupação pelos frades carmelitas, exigida pela extinção das ordens religiosas e a sua reutilização atual que contribui para que este património continue vivo e em condições de ser transmitido às gerações vindouras, nas melhores condições. O Convento de Nossa Senhora dos Remédios, foi casa religiosa fundada por iniciativa do bispo de Évora D. Teotónio de Bragança datando a sagração da igreja conventual do ano de 1614. Integrando a reformada Ordem dos Carmelitas possuía regra austera que obrigava a pobreza e despojamento rigorosos. O carisma contemplativo e apostólico das comunidades dos Carmelitas Descalços inspiravam-se na acção de Jesus “ora orando isolado no deserto, ora em piedosa intervenção quando no meio da multidão”. Situando-se o convento no exterior da muralha medieva, em área anexa às Portas de Alconchel, à época principal ligação da cidade com o exterior, era local privilegiado de circulação de pessoas e bens. Possui a igreja orientação sudeste/noroeste desenvolvendo-se o claustro para sudoeste, rodeando-se este com os compartimentos necessários à vida da comunidade religiosa: a sudeste, a ala onde se situava a sala do Capítulo, refeitório e escada “regular” de acesso ao dormitório do piso superior, subdividido em celas; a sudoeste dependências de serviço, nomeadamente o refeitório e cozinha; a noroeste, localiza-se a igreja assim como o pequeno compartimento para os livros de orações e a noroeste, na ala dos “mossos”, localiza-se ainda hoje a primitiva portaria. Possivelmente existiriam aí outros compartimentos como sala de aula, hospedaria, enfermaria, refeitório para os “noviços”, dependências para armazenamento de víveres e um acesso entre os dois pisos a ligar ao dormitório. No tardoz do altar-mor da igreja, no prolongamento da ala claustral, existe ainda hoje a sacristia assim como capela mortuária de um dos benfeitores da casa. A cerca conventual envolvia o conjunto edificado pelos lados sudoeste e sueste situando-se as ligações com o espaço público a noroeste. Passados cerca de 200 anos sobre a sua saída dos frades carmelitas, a igreja é utilizada atualmente para a realização de recitais e aulas de música clássica e canto, a capela funerária é ocupada por gabinete, a sacristia é local de aulas de música, a sala do capítulo foi transformada em espaço para crianças mantendo o “refeitório dos frades” a anterior função. As alas sudoeste e dos “mossos” estão totalmente reestruturadas sendo hoje ampla galeria de exposições. O andar superior ocupado pelas celas foi totalmente remodelado aí existindo amplos espaços destinados a exposições e actividades complementares. A cerca, cedida pela Fazenda Pública à Câmara Municipal de Évora em 1839, foi no ano seguinte reutilizada como cemitério. Os serviços necessários à sua manutenção encontram-se igualmente instalados no atual conjunto edificado

Tiny Medicine: Nanomaterial-Based Biosensors

Tiny medicine refers to the development of small easy to use devices that can help in the early diagnosis and treatment of disease. Early diagnosis is the key to successfully treating many diseases. Nanomaterial-based biosensors utilize the unique properties of biological and physical nanomaterials to recognize a target molecule and effect transduction of an electronic signal. In general, the advantages of nanomaterial-based biosensors are fast response, small size, high sensitivity, and portability compared to existing large electrodes and sensors. Systems integration is the core technology that enables tiny medicine. Integration of nanomaterials, microfluidics, automatic samplers, and transduction devices on a single chip provides many advantages for point of care devices such as biosensors. Biosensors are also being used as new analytical tools to study medicine. Thus this paper reviews how nanomaterials can be used to build biosensors and how these biosensors can help now and in the future to detect disease and monitor therapies

Review: The increasing importance of carbon nanotubes and nanostructured conducting polymers in biosensors

The growing need for analytical devices requiring smaller sample volumes, decreased power consumption and improved performance have been driving forces behind the rapid growth in nanomaterials research. Due to their dimensions, nanostructured materials display unique properties not traditionally observed in bulk materials. Characteristics such as increased surface area along with enhanced electrical/optical properties make them suitable for numerous applications such as nanoelectronics, photovoltaics and chemical/biological sensing. In this review we examine the potential that exists to use nanostructured materials for biosensor devices. By incorporating nanomaterials, it is possible to achieve enhanced sensitivity, improved response time and smaller size. Here we report some of the success that has been achieved in this area. Many nanoparticle and nanofibre geometries are particularly relevant, but in this paper we specifically focus on organic nanostructures, reviewing conducting polymer nanostructures and carbon nanotubes

Prospects of Nanotechnology in Clinical Immunodiagnostics

Nanostructured materials are promising compounds that offer new opportunities as sensing platforms for the detection of biomolecules. Having micrometer-scale length and nanometer-scale diameters, nanomaterials can be manipulated with current nanofabrication methods, as well as self-assembly techniques, to fabricate nanoscale bio-sensing devices. Nanostructured materials possess extraordinary physical, mechanical, electrical, thermal and multifunctional properties. Such unique properties advocate their use as biomimetic membranes to immobilize and modify biomolecules on the surface of nanoparticles. Alignment, uniform dispersion, selective growth and diameter control are general parameters which play critical roles in the successful integration of nanostructures for the fabrication of bioelectronic sensing devices. In this review, we focus on different types and aspects of nanomaterials, including their synthesis, properties, conjugation with biomolecules and their application in the construction of immunosensing devices. Some key results from each cited article are summarized by relating the concept and mechanism behind each sensor, experimental conditions and the behavior of the sensor under different conditions, etc. The variety of nanomaterial-based bioelectronic devices exhibiting novel functions proves the unique properties of nanomaterials in such sensing devices, which will surely continue to expand in the future. Such nanomaterial based devices are expected to have a major impact in clinical immunodiagnostics, environmental monitoring, security surveillance and for ensuring food safety

Properties and customization of sensor materials for biomedical applications.

Low-power chemo- and biosensing devices capable of monitoring clinically important parameters in real time represent a great challenge in the analytical field as the issue of sensor calibration pertaining to keeping the response within an accurate calibration domain is particularly significant (1–4). Diagnostics, personal health, and related costs will also benefit from the introduction of sensors technology (5–7). In addition, with the introduction of Registration, Evaluation, Authorization, and Restriction of Chemical Substances (REACH) regulation, unraveling the cause–effect relationships in epidemiology studies will be of outmost importance to help establish reliable environmental policies aimed at protecting the health of individuals and communities (8–10). For instance, the effect of low concentration of toxic elements is seldom investigated as physicians do not have means to access the data (11)