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A Fluorescent Supramolecular Biosensor for Bacterial Detection via Binding-Induced Changes in Coiled-Coil Molecular Assembly
摘要： The essential elements required for any sensors are a receptor, a signal converter, and a detector. Here, we report the construction of bacterial biosensors in which all of the required biosensor elements are furnished in one supramolecular assembly. The supramolecular biosensor is based on a double-layered octa-helical coiled-coil peptide assembly that contains tetravalent bioreceptors on the outer surface and environment-sensitive fluorophores in the core. The signal conversion takes advantage of the noncovalent and reversible nature of the self-assembled system, i.e., the multivalent binding of bacteria induces conformational changes in the supramolecular state, which is translated into differential fluorescence emissions. We show that fluorescent supramolecular biosensors (fSBs) can selectively detect E. coli over other bacteria. Because the fSBs were resistant to heat-induced denaturation, they retained their bacterial-sensing capability even at an elevated temperature (50 ℃). Biosensors based on responsive supramolecular assemblies can be further developed to detect various large and flat biological objects and biomacromolecules.
关键词： Escherichia coli,Supramolecule,Biosensor,Bacteria,Self-assembly,Peptide-based probe
更新于2025-11-21 11:08:12
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Improved stability in <scp>P3HT</scp> : <scp>PCBM</scp> photovoltaics by incorporation of <scp>wella??designed</scp> polythiophene/graphene compositions
摘要： Morphological and photovoltaic stabilities of poly(3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PC71BM) solar cells were investigated in pristine and modified states. To this end, the four types of patterned/assembled nanostructures, such as reduced graphene oxide (rGO)-g-poly(3-dodecylthiophene) (PDDT)/P3HT patched-like pattern, rGO-polythiophene (GPTh)/P3HT/PC71BM nanofiber, rGO-g-P3HT/P3HT cake-like pattern and supra(polyaniline (PANI)-g-rGO/P3HT) were designed on the basis of rGO and different conjugated polymers. Intermediately covered rGO nanosheets by the P3HT crystals (supra(PANI-g-rGO/P3HT)) acted better than rarely (patched-like pattern) and fully (cake-like pattern) covered ones in P3HT:PC71BM solar systems. Supra(PANI-g-rGO/P3HT) nano-hybrids largely phase separated in active layers (root mean square = 0.88 nm) and also reflected the highest performance (PCE = 5.74%). The photovoltaic characteristics demonstrated the plummeting trends during the air aging for all sorts of devices, but with distinct slopes. The steepest decreasing plots were obtained for the unmodified P3HT:PC71BM devices (from 1.77 to 0.28%). The two last supramolecules with the most ordered structures, i.e., cake-like pattern (10.12 mA/cm2, 51%, 0.58 V, 2.2 × 10–6 cm2/V.s, 4.3 × 10–5 cm2/V.s, 0.69 nm and 2.99%) and supra(PANI-g-rGO/P3HT) (12.51 mA/cm2, 57%, 0.63 V, 1.2 × 10–5 cm2/V.s, 3.4 × 10–4 cm2/V.s, 0.82 nm and 4.49%), highly retained the morphological and photovoltaic stabilities in P3HT:PC71BM devices after 1 month air aging. According to the morphological, optical, photovoltaic and electrochemical results, the supra(PANI-g-rGO/P3HT) nano-hybrids were the best candidates for stabilizing the P3HT:PC71BM solar cells.
关键词： Stability,air aging,P3HT,supramolecule,PC71BM
更新于2025-09-23 15:19:57
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Selectivity, Thermodynamic and Anisotropic Properties of Substituted Liquid-Crystal Cyanoazoxybenzenes as Stationary Phases for Gas Chromatography
摘要： Herein we discuss physical properties of 4-(ω-hydroxyalkoxy)-4’-cyanoazoxybenzene homologs. 1D and 2D correlation NMR spectroscopy (in particular, 1Н, 15N-HMBC experiment) have allowed elucidation of structure of the prepared rod-like supramolecular cyanoazoxybenzenes. Mesomorphic properties of the compounds have been studied by means of polarization thermomicroscopy and differential scanning calorimetry. All the studied cyanoazoxybenzenes have revealed enantiotropic nematic mesomorphism over wide temperature range. Nematic mesophase of the eighth homolog has possessed large positive dielectric anisotropy. Introduction of small amounts of the prepared cyanoazoxybenzenes as additive has stabilized the mesophase and has increased the dielectric anisotropy of 4-pentyloxy-4’-cyanobiphenyl. Gas-liquid chromatography studies have shown that sorbents based on 4-(2-hydroxyethyloxy)-4’-cyanoazoxybenzene are highly selective towards various structural isomers; that cannot be achieved using conventional nematic liquid crystals. Thermodynamic evidence of specific interactions between the mesogen and the non-mesomorphic sorbate has been discovered.
关键词： Mesogen,Dielectric anisotropy,Sorbent,Hydrogen bond,Structural selectivity,NMR spectroscopy,Nematic phase,Position isomerism,Azoxybenzene,Double refraction,Supramolecule
更新于2025-09-19 17:15:36
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Elevated air stability in PBDT-DTNT:PCBM solar cells by focusing on roles of fibrillar/patterned nanostructures via graphene/polymer constituents
摘要： Morphological, electrochemical, and photovoltaic stabilities of the poly[benzodithiophene-bis(decyltetradecylthien) naphthothiadiazole] (PBDT-DTNT):phenyl-C61-butyric acid methyl ester (PC71BM) solar cells were promoted by the pre-designed supramolecules on the basis of reduced graphene oxide (rGO) nanosheets. Nanostructures consisted of the pristine rGO, grafted-rGO/PBDT-DTNT, rGO-polythiophene (GPTh) electrospun nanofiber, grafted-rGO/PBDT-DTNT electrospun nanofiber and rGO/PBDT-DTNT samples. The reduction in photovoltaic characteristics during air aging was the steepest for the unmodified PBDT-DTNT:PC71BM solar cells. From rGO based photovoltaics towards the rGO/PBDT-DTNT modified ones possessing the well-patterned PBDT-DTNT nanofibers, the slopes of graphs decreased. The most stabilized devices were fabricated on the basis of PBDT-DTNT:PC71BM:rGO/PBDT-DTNT active layers (power conversion efficiency (PCE) from 6.09% for upon-fabricated to 4.87% for 1 month aged systems) for having the most red-shifted and intensified absorbance, the largest phase separation, the lowest impedance responses and the highest photovoltaic characteristics during 1 month air aging (short circuit current density (Jsc) of 12.09 mA/cm2, fill factor (FF) of 63%, open circuit voltage (Voc) of 0.64 V, hole mobility (μh) of 5.3 × 10–5 cm2/V s, electron mobility (μe) of 7.9 × 10–4 cm2/V s, charge transfer resistance (Rtr) of 431 Ω cm2 and PCE of 4.87%). The GPTh/PBDT-DTNT/PC71BM (Jsc = 10.31 mA/cm2, FF = 49%, Voc = 0.55 V, Rtr = 796 Ω cm2 and PCE = 2.78%) and grafted-rGO/PBDT-DTNT/PBDT-DTNT (Jsc = 10.98 mA/cm2, FF = 56%, Voc = 0.60 V, Rtr = 539 Ω cm2 and PCE = 3.69%) electrospun nanofibers also imparted the stabilization of devices within 1 month.
关键词： Stability,rGO,Supramolecule,PBDT-DTNT
更新于2025-09-16 10:30:52