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A highly selective and sensitive electrogenerated chemiluminescence (ECL) biosensor for the detection of prostate PC-3 cancer cells was designed using a prostate specific antibody as a capture probe and ruthenium complex-labelled wheat germ agglutinin as a signal probe. The ECL biosensor was fabricated by covalently immobilising the capture probe on a graphene oxide-coated glassy carbon electrode. Target PC-3 cells were selectively captured on the surface of the biosensor, and then, the signal probe was bound with the captured PC-3 cells to form a sandwich. In the presence of tripropylamine, the ECL intensity of the sandwich biosensor was logarithmically directly proportion to the concentration of PC-3 cells over a range from 7.0×10(2) to 3.0×10(4) cells mL(-1), with a detection limit of 2.6×10(2) cells mL(-1). The ECL biosensor was also applied to detect prostate specific antigen with a detection limit of 0.1 ng mL(-1). The high selectivity of the biosensor was demonstrated in comparison with that of a lectin-based biosensor. The strategy developed in this study may be a promising approach and could be extended to the design of ECL biosensors for highly sensitive and selective detection of other cancer-related cells or cancer biomarkers using different probes., (Copyright © 2014. Published by Elsevier B.V.)

Carbon nanotubes (CNTs) have unusual physical properties that are valuable for nanotechnology and electronics, but the chemical synthesis of chirality‐ and diameter‐specific CNTs and π‐conjugated CNT segments is still a great challenge. Reported here are the selective syntheses, isolations, characterizations, and photophysical properties of two novel chiral conjugated macrocycles ([4]cyclo‐2,6‐anthracene; [4]CAn2,6), as (−)/(+)‐(12,4) carbon nanotube segments. These conjugated macrocyclic molecules were obtained using a bottom‐up assembly approach and subsequent reductive elimination reaction. The hoop‐shaped molecules can be directly viewed by a STM technique. In addition, chiral enantiomers with (−)/(+) helicity of the [4]CAn2,6 were successfully isolated by HPLC. The new tubular CNT segments exhibit large absorption and photoluminescence redshifts compared to the monomer unit. The carbon enantiomers are also observed to show strong circularly polarized luminescence (glum≈0.1). The results reported here expand the scope of materials design for bottom‐up synthesis of chiral macrocycles and enrich existing knowledge of their optoelectronic properties. [ABSTRACT FROM AUTHOR]

Stimuli‐responsive organic luminescence‐switching materials have attracted much attention for a decade. Most of the reported examples display a reversible two‐color luminescence switching, and multicolor‐switching materials remain extremely rare. Herein, we report a simple organic molecule, 4,4′‐(9,9‐dimethyl‐9H‐fluorene‐2,7‐diyl)dipyridine (MFDP), which exhibits three different crystal polymorphs (V‐MFDP, B‐MFDP and G‐MFDP) with different luminescent colors. Furthermore, the three crystal polymorphs show a reversible tricolor fluorescent switching from violet to blue and to green upon physical stimuli. The single‐crystal structures of the three polymorphs were obtained, and the results indicate that the stimuli‐responsive properties of the three polymorphs come from the different stacking modes induced by intermolecular interactions. The competition between weak π–π stacking and weak hydrogen bonding is the main reason for the the phase transformations among the three crystal polymorphs. Tricolor neons: A fluorene‐based functional molecule is reported which exhibits three different crystal polymorphs with different luminescent colors. The tricolor luminescence can be reversibly switched by thermal and mechanical stimuli. The crystal structures revealed the mechanism of the phase transformation and luminescence switching. [ABSTRACT FROM AUTHOR]

C 3 -symmetric truxene and triindole have been widely used to design the branched optoelectronic molecules. However, most of them exhibit high luminous efficiency in the solution and quenched luminescence in the solid state. Here, we respectively chose alkylated truxene and triindole as the central core, 2-methylphenyl as the peripheral functional groups to synthesize three branched compounds. Their photophysical properties have been explored combining with the theoretical calculation. The three compounds exhibit good solubility and high solid-state fluorescence quantum yields. The absorption and emission peaks of triindole compound exhibit apparent red-shift in comparison with those of truxene compounds, which indicates triindole more highly electron delocalization than truxene. The single-crystal structure shows that alkylation of the central core and branched steric bulkiness of these molecules effectively reduce the intermolecular π ⋯ π stacking and avoid the non-radiative transition of these molecules from excited state to ground state in the solid state. [ABSTRACT FROM AUTHOR]

Aggregation-induced emission (AIE) has attracted considerable interest in recent years. An understanding of the underlying mechanisms for the AIE phenomena is also of great importance. Here, we synthesized four fluorenone derivatives, which all show typical AIE properties. Their enhanced solid-state luminescence showed a 160 nm red-shift (from 380 to 540 nm) in comparison to their luminescence in dilute tetrahydrofuran (THF) solutions. The single-crystal structure and photophysical properties revealed that the bathochromic luminescence is due to the formation of static excimers. To further demonstrate the AIE mechanism of static excimers, rather than restricted intramolecular rotation (RIR), we designed a diphenylfluorenone-diboronic acid adduct, which can react with d -glucose to create structurally rigid oligomers, resulting in the restriction of intramolecular rotations. The spectral change in the d -glucose titration of the adduct indicated that the bathochromic AIE of these fluorenone compounds cannot possibly be caused by RIR and conformational planarization. [ABSTRACT FROM AUTHOR]

Eu 2+ /Eu 3+ -doped fluorophosphate Na 5 Al(PO 4 ) 2 F 2 was synthesized by the high-temperature solid-state reaction. The structural XRD refinement was used to investigate the phase formation and structure. The photoluminescence (PL) excitation and emission spectra were measured. The host accommodates two kinds of Eu-centers in the lattices, i.e., Eu 3+ and Eu 2+ , which were confirmed by the emission spectra and decay curves. Under the excitation of UV and near-UV light, the broad emission peaked at 420 nm and 530 nm from the 4 f 6 5 d –4 f 7 transition of Eu 2+ and narrow peaks at 592 nm, 615 nm from the 4 f –4 f transitions of Eu 3+ ions were detected. The luminescence color could shift from blue to white and red by mixing the luminescence from the coexistence of Eu 2+ /Eu 3+ ions in the single-phase phosphor. [ABSTRACT FROM AUTHOR]

Organicsolid-state luminescence switching (SLS) materials withthe ability to reversibly switch the luminescence by altering themode of molecular packing without changing the chemical structuresof their component molecules have attracted considerable interestin recent years. In this work, we design and synthesize a new classof 2,7-diphenylfluorenone derivatives (compounds 1–6) that exhibit prominent aggregation-induced emission (AIE)properties with high solid-state fluorescence quantum yields (29–65%).Among them, 2,7-bis(4-methoxyphenyl)-9H-fluoren-9-one(2) and 2,7-bis(4-ethylphenyl)-9H-fluoren-9-one(6) display reversible stimuli-responsive solid-stateluminescence switching. Compound 2transforms betweenred and yellow crystals (the emission wavelength switches between601 and 551 nm) under the stimuli of temperature, pressure, or solventvapor. Similarly, compound 6exhibits SLS behavior, withluminescence switching between orange (571 nm) and yellow (557 nm).Eight X-ray single-crystal structures, characterization of the photophysicalproperties, powder X-ray diffraction, and differential scanning calorimetryprovide insight into the structure–property relationships ofthe solid-state fluorescence behavior. The results indicate that thevariable solid-state luminescence of the fluorenone derivatives isattributed to the formation of different excimers in different solidphases. Additionally, the stimuli-responsive reversible phase transformationsof compounds 2and 6involve a structuraltransition between π–π stacking-directed packingand hydrogen bond-directed packing. The results also demonstrate thefeasibility of our design strategy for new solid-state luminescenceswitching materials: introduction of both π–π stackingand hydrogen bonding into an AIE structure to obtain a metastablesolid/crystalline state luminescence system. [ABSTRACT FROM AUTHOR]

Self-activated Ba2V2O7 phosphor microrods are prepared by hydrothermal reaction of Ba(NO3)2 and V2O5 in aq. [ABSTRACT FROM AUTHOR]