Photo-responsive polymer materials for biological applications

In this review, we briefly summarized the remarkable progress of photo-responsive polymer materials from zero-dimensional micelles, twodimensional surfaces to three-dimensional hydrogels with irreversible or reversible moieties. Based on the photo-responsiveness, polymer have been designed, synthesized and applied for various biological fields including drug delivery and cell manipulation.     

Lanthanide-containing polymer nanoparticles for biological tagging applications: nonspecific endocytosis and cell adhesion

We describe the synthesis and characterization of element-encoded polystyrene nanoparticles with diameters on the order of 100 nm and a narrow size distribution. Individual particles contain ca. 10(3) chelated lanthanide ions, of either a single element or a mixture of elements. These particles were effectively internalized by nonspecific endocytosis into three cell lines associated with human leukemia. Using an assay based upon ICP-MS detection, we could monitor quantitatively cell adhesion induced by cell differentiation of THP-1 cells in response to phorbol ester stimulation (PMA) in single cell type or mixed cultures.     

Hollow polymer shells from biological templates: fabrication and potential applications

Three-dimensional ultrathin polymer shells have been produced by a combination of step-by-step adsorption of polyelectrolytes on glutaraldehyde-treated human erythrocytes and subsequent solubilization of the cytoplasmatic constituents by means of a deproteinizing agent. The obtained hollow films preserve both the size and shape of the templating cells. This opens a pathway for the fabrication of polymeric capsules within a wide range of size and shape by using various biological templates. They may have exciting potential applications, such as templates for nanocomposites, as containers for a large class of materials, or as cages for chemical reactions. The thickness of the films can be adjusted over a large range: from a few nm up to several tens of nm. The polymer shells are permeable to small molecules and ions but not to macromolecules. An increase in the ionic strength of the solution up to 100 mmol make the capsules permeable for proteins. Permeability and conductivity studies have provided evidence that the adsorption of lipids on polyelectrolyte layers is a means of producing capsules with controlled permeability properties. 6-Carboxyfluorescein and Rhodamin 6G were precipitated within the capsules.     

Thermal analysis in biological and medical applications

In this paper, I will sum up our research activity from this field performed in the last about 25 years. I will focus on three main points: basic muscle research in the different intermediate states of ATP hydrolysis cycle during muscle contraction, R&D activities to develop and test different dairy products and TA application in some surgical and diagnostic problem. Our initial research concerned the investigation of thermal stability of main muscle proteins clarifies their basic unfolding characteristics. Later we extended the thermal stability investigation from protein solution to the myosin myofibrils and to the higher organization of muscle proteins, the muscle fibres, checking the effect of nucleotides. At that time, it became possible to stabilize the different intermediate states of ATP hydrolysis up to the time of DSC measurement, using different P_i analogues (V_i, AlF_x and BeF_x) and non-hydrolysable ATP analogue (AMP.PNP). This way the targets were AM.ADP.V_i (and with AlF_x or BeF_x) so-called weak binding state, AM.ADP the “strong” binding state as well as the “rigor” AM complex state. AM.AMP.PNP state was used to mimic the AM.ATP state. With our R&D cooperation, a cold spreadable butter was successfully developed. We were a partner in the development of Ca-enriched cheese, in its spreadable form too as well as in the development and testing of different dairy products using probiotic cultures. Our TA activity covers a wide range of medical applications, e.g. investigation of the different abnormalities of human leg skeletal muscle, different stages of degeneration of human vertebral disc, to judge the goodness/applicability of different suture technique on tracheal cartilage in primary airway reconstruction or the characterization of different self-expandable stents implantation in the oesophagus treatment. We have joined those groups who try to use DSC in the diagnosis of different diseases from blood plasma, e.g. in the case of breast cancer, melanoma, in psoriasis.     

Liquid phase microextraction applications in food analysis

Over the last years, liquid-phase microextraction (LPME) in its different application modes (single drop microextraction, dispersive liquid-liquid microextraction and hollow fiber-LPME) has been increasingly applied for the extraction of both inorganic and organic analytes from different matrices. Its advantages over conventional extraction procedures (simplicity, effectiveness, rapidity and low consumption of organic solvents) has also attracted its application in the complex food analysis field, in which it has clearly provided good and challenging results. A comprehensive review dealing with those articles published since its introduction till the end of March 2011 is presented, offering also a critical vision of the analytical potential of LPME for the analysis of foods.     

Liquid crystals for display applications

Active Matrix (AM) LCDs and STN LCDs are the leading display technologies for portable applications such as notebook computers. Recently, new LCD device configurations and new LCD operation modes have been introduced. The existing technologies and the new LCD operation modes require improved liquid crystal materials. The history of liquid crystals for display applications and recent progress in new liquid crystal structures is presented.     

Zeolite micropattern for biological applications

A facile method was established using composition-gradient pattern on zeolite surface to guide the deposition and formation of chemical and biomolecular patterns with features as small as five microns.     

Liquid crystals for AMLCD and TFT-PDLCD applications

This paper presents a review of the work on the molecular design of liquid crystals for active matrix displays (AMLCDs), thin-film-transistor-polymer dispersed liquid crystal displays (TFT-PDLCDs) and examines in some detail the relationships between liquid crystalline molecular structures and their physico-chemical properties.     

Tubular conjugated polymer for chemosensory applications

In this paper, we present the concept of a soluble tubular conjugated polymer (TCP). We report on a fluorescent 5,5'-Bicalixarene-based polymer where the calixarene units are seamlessly incorporated in the conjugated polymeric chain that can respond to a small molecule complexation inside the hydrophobic cavity. In particular, our system demonstrated a reversible rapid fluorescence quenching upon interaction of gaseous nitric oxide with the calixarene moiety.     

Industrial applications of supercritical fluid chromatography: polymer analysis

Summary Polymers can be difficult to fully characterize by conventional chromatographic methods [i.e., gas chromatography (GC), high performance liquid chromatography (HPLC) and size exclusion chromatography (SEC)] due to temperature instability, detector incompatibility, nonvolatility, molecular weight considerations or insufficient chromatographic efficiency. Capillary supercritical fluid chromatography (SFC) offers several advantages for polymer analysis. Complex distributions can be resolved, low temperatures can be used and individual oligomers can be detected, allowing differences in molecular weight distributions to be quantitatively and qualitatively measured. In this paper, results will be shown for the analysis of various types of polymers demonstrating how changes in chromatographic parameters affect the analysis

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Industrielle Anwendungen der Chromatographie mit überkritischen fluiden Phasen: Polymeranalyse

     

Magnetic polymer nanocomposites for environmental and biomedical applications

Hybrid nanomaterials have received voluminous interest due to the combination of unique properties of organic and inorganic component in one material. In this class, magnetic polymer nanocomposites are of particular interest because of the combination of excellent magnetic properties, stability, and good biocompatibility. Organic–inorganic magnetic nanocomposites can be prepared by in situ, ex situ, microwave reflux, co-precipitation, melt blending, and ceramic–glass processing and plasma polymerization techniques. These nanocomposites have been exploited for in vivo imaging, as superparamagnetic or negative contrast agents, drug carriers, heavy metal adsorbents, and magnetically recoverable photocatalysts for degradation of organic pollutants. This review article is mainly focused on fabrication of magnetic polymer nanocomposites and their applications. Different types of magnetic nanoparticles, methods of their synthesis, properties, and applications have also been reviewed briefly. The review also provides detailed insight into various types of magnetic nanocomposites and their synthesis. Diverse applications of magnetic nanocomposites including environmental and biomedical uses have been discussed.     

Near-infrared light for polymer re-shaping and re-processing applications

The re-shaping and reprocessing of polymers are usually associated with strong energetic costs, strongly limiting their practical usage. In this article, a new approach is proposed based on a near-infrared (NIR) activation of the material in presence of a NIR heater for a highly efficient process upon ecofriendly NIR light emitting diodes irradiation. Markedly, due to this light-triggered process, a spatial control of the shaping/reprocessing behavior can be obtained, that is, only the needed parts are irradiated preventing a heating of all the sample. In this work, different thermoplastics are reshaped or reprocessed due to NIR activation in presence of an organic NIR dye used as heater. As other examples of photothermal treatment upon NIR light, the on-demand dehydration of polyethylene glycol (PEG-based) hydrogels are also provided. All the processes are followed in real time by thermal imaging camera.     

A photopatternable silicone for biological applications

We show the application of a commercially available photopatternable silicone (PPS) that combines the advantageous features of both PDMS and SU-8 to address a critical bioMEMS materials deficiency. Using PPS, we demonstrate the ability to pattern free-standing mechanically isolated elastomeric structures on a silicon substrate: a feat that is challenging to accomplish using soft lithography-based fabrication. PPS readily integrates with many cell-based bioMEMS since it exhibits low autofluorescence and cells easily attach and proliferate on PPS-coated substrates. Because of its inherent photopatternable properties, PPS is compatible with standard microfabrication processes and easily aligns to complex featured substrates on a wafer scale. By leveraging PPS' unique properties, we demonstrate the design of a simple dielectrophoresis-based bioMEMS device for patterning mammalian cells. The key material properties and integration capabilities explored in this work should present new avenues for exploring silicone microstructures for the design and implementation of increasingly complex bioMEMS architectures.     

Polysaccharides based hydrogels for biological applications

Polysaccharides based hydrogels show several peculiar properties which can be so reassumed: • Capability to absorb a great amount of water once immersed in biological fluids, assuming, consequently, a structure similar to extracellular matrix or biological tissue • Tissotropic property, i.e. possibility to be injected through a needle without lose of their rheological properties. These fundamental properties make them ideal materials for several biomedical applications, such as cellular scaffold, coatings for biomedical disposals, treatments for different diseases, controlled release of drugs, etc. Hyaluronane, Carboxymethyl cellulose and Alginic acid based 50% hydrogels (i.e. 50% of the carboxylate groups present in the macromolecule chain were involved in the cross-linking reaction) are synthesised. Their effectiveness in promoting cells adhesion and proliferation was verified. Furthermore the possibility of injecting and sterilising hydrogels permitted to test the effect of Hyal 50% in the osteoarthritis therapy. It was found that the in vivo effect of Hyal 50% in the treatment of surgically created chondral defect in the rabbit knee was positive. These materials can be both chemically and morphologically modified. In fact, the insertion of sulphate groups increase their hemocompatibility as demonstred by the increase of TT (time necessary to turn the fibrinogen to thrombin). Furthermore microporous hydrogels were obtained and tested as drug controlled release systems.     

Biocompatible quantum dots for biological applications

Semiconductor quantum dots are quickly becoming a critical diagnostic tool for discerning cellular function at the molecular level. Their high brightness, long-lasting, size-tunable, and narrow luminescence set them apart from conventional fluorescence dyes. Quantum dots are being developed for a variety of biologically oriented applications, including fluorescent assays for drug discovery, disease detection, single protein tracking, and intracellular reporting. This review introduces the science behind quantum dots and describes how they are made biologically compatible. Several applications are also included, illustrating strategies toward target specificity, and are followed by a discussion on the limitations of quantum dot approaches. The article is concluded with a look at the future direction of quantum dots.     

Polymeric actuators for biological applications.

To shed light on the role of cell rheology and mechanotransduction in various physiological and disease states, different techniques of force application, such as optical tweezers and deformable substrates, are employed. In this present paper we describe a new approach for the deformation of cells based on the temperature-sensitive polymer poly(N-isopropylacrylamide), PNIPAM. In response to temperature changes, PNIPAM gels undergo extensive and reversible changes in volume that allow them to be used as actuators for stretching and compressing cells and tissues. Herein we focus mainly on our experience with the deformation of red blood cells as proof of principle, and demonstrate the wealth of possibilities such stimuli-responsive materials may offer as actuators.     

Graphene/polymer composites for energy applications

Graphene has wide potential applications in energy-related systems, mainly because of its unique atom-thick two-dimensional structure, high electrical or thermal conductivity, optical transparency, great mechanical strength, inherent flexibility, and huge specific surface area. For this purpose, graphene materials are frequently blended with polymers to form composites, especially when fabricating flexible devices. Graphene/polymer composites have been explored as electrodes of supercapacitors or lithium ion batteries, counter electrodes of dye-sensitized solar cells, transparent conducting electrodes and active layers of organic solar cells, catalytic electrodes, and polymer electrolyte membranes of fuel cells. In this review, we summarize the recent advances on the synthesis and applications of graphene/polymer composites for energy applications. The challenges and prospects in this field have also been discussed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013     

Liquid crystal polymer optics

In this paper we give a concise overview of various optical applications of Liquid Crystalline side‐chain polymers. The possibility to tune the LC structure and phase‐diagrams, as well as the availability of methods to create specific structures in the director field, allows materials to be developed for data‐storage media and as optical compensation films for LC display applications.     

Direct PCR analysis of biological samples in disposable plastic microreactors for biochip applications

In this work we show the development and assessment of disposable, biocompatible, fully plastic microreactors, which are demonstrated to be highly efficient for performing on-chip direct PCR analyses of very diverse crude biological samples, such as human cells, whole blood, buccal scrape and hair bulbs, without requiring any purification steps before PCR analyses.