TY - JOUR A1 - Wang, X.-D. A1 - Meier, R.J. A1 - Schmittlein, C. A1 - Schreml, S. A1 - Schäferling, Michael A1 - Wolfbeis, Otto S. T1 - A water-sprayable, thermogelating and biocompatible polymer host for use in fluorescent chemical sensing and imaging of oxygen, pH values and temperature N2 - We report on the use of a sprayable and thermogelating biomaterial (Poloxamer™; a.k.a. Pluronic™) in optical imaging of pH values, local oxygen and temperature. The material is highly biocompatible and easy to handle. We also show that the material is well permeable to oxygen (thus making it a good choice for use in oxygen sensors), and is stable in liquid solution and at elevated temperature. We demonstrate its applicability in optical sensors for oxygen, pH and temperature. This was accomplished by incorporating appropriate luminescent probes in various kinds of microparticles (which act as hosts for the probes and prevent dye leaching and aggregation), and then dispersing the microparticles in the thermogelating polymer. The resulting sensor gels were deposited on the surface of interest via spraying at temperatures of <20 °C. At these temperatures, the gels adhere well to the target, even on uneven surfaces such as skin, wounds, and bacterial cultures. If temperature is risen to above 25 °C, the gels form a thin and soft but solid sensing layer which, however, can be simply removed from surface of interest by cooling and wiping it off, or by washing with water. Sprayable thermogelating sensors present obvious advantages over other sensors by not causing damage to the surface of interest. In our perception, the sensing materials also have wide further applicability in sensors for other species including clinically relevant gases, enzyme substrates (such as glucose or lactate) and ions. KW - Chemical sensing KW - Imaging KW - Biocompatible polymer KW - Sprayable sensor KW - Fluorescence KW - Poloxamer KW - Pluronic KW - Oxygen sensor KW - pH sensor KW - Temperature sensor PY - 2015 DO - https://doi.org/10.1016/j.snb.2015.05.082 SN - 0925-4005 SN - 1873-3077 VL - 221 SP - 37 EP - 44 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-33855 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Schäferling, Michael ED - Meyers, R.A. T1 - Fluorescence-based biosensors N2 - Biosensors, as defined by Pure and Applied Chemistry, are ‘chemical sensors in which the recognition System utilizes a biochemical mechanism. The biological recognition system translates information from the biochemical domain, usually an analyte concentration, into a chemical or physical output signal with a defined sensitivity’.(1) It is also appointed that chemical or biological sensors contain two basic components connected in series: a chemical or biomolecular recognition System (receptor) and a physicochemical transducer. According to this prerequisite, this overlook is confined to sensor devices that combine a biomolecular recognition element with an optical signal transducer. Homogeneous or intracellular assays using fluorescent molecular probes or nanoparticles are not considered, although they are frequently termed as molecular sensors or nanosensors in the literature. Fluorescence-based biosensors are generalized as those devices that derive an analytical signal from a photoluminescent (either fluorescence or phosphorescence) emission process. Chemi- or bioluminescent detection systems are only briefly discussed in this review. Biosensors are used for a wide variety of tasks, including detection of compounds of biomedical, environmental or defense interest; on-line monitoring for process control; quality control of foodstuffs; selective detection of compounds undergoing a chemical separation; and screening of drug compounds. Advantages of such devices include high selectivity, rapid response times, reusability, amenability to remote analysis, and immunity to electrical interferences. The selective nature of complexation between biomolecule and analyte and the small size of sensor devices can be combined with advanced detection techiques such as total internal reflection (TIR) spectroscopy. This results in an ability to measure analytes in complex matrices with unsurpassed sensitivity. Such samples may include highly scattering components such as milk or whole blood,(11) or relatively inaccessible locations such as groundwater wells, or even intracellular environments. The key limitation of such devices mainly centers on the poor stability of biological compounds, which can lead to a substantial drift in instrumental response over time. The so-called Cambridge Definition appoints another characteristic property of sensors. Therein, they are defined as ‘miniaturized devices which can deliver real-time and on-line information on the presence of specific compounds or ions in even complex samples’. Accordingly, a sensor is expected to respond reversibly and continuously. With the exception of some enzymatic sensors, these conditions are not fulfilled in case of most biosensors. Particularly, in devices where immunological reagents or DNA are used as recognition elements, they show a lack of reversibility and operate only as a ‘one-shot’ screen, without the potential for continuous, quantitative analysis. Nevertheless, the designations immunosensors or DNA sensors became accepted for such analytical or diagnostic tools. KW - Biosensor KW - Fluorescence KW - Immunoassay KW - Enzyme sensor KW - DNA sensor PY - 2016 UR - http://onlinelibrary.wiley.com/doi/10.1002/9780470027318.a0206.pub3/abstract SN - 9780470027318 DO - https://doi.org/10.1002/9780470027318.a0206.pub3 SP - 1 EP - 51 PB - John Wiley & Sons AN - OPUS4-38741 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -