Impedance spectroscopy for identifying tau protein to monitor anesthesia-based issues.

Anesthesia-related drugs cause various side effects and health-related illnesses after surgery. In particular, neurogenerative disorder is a common problem of anesthesia-related drugs. A patient gets anesthesia as a requirement of the preoperative evaluation to diagnose the medical illness, which is caused by anesthetic drug treatment. Different blood-based biomarkers help in identifying the changes appearing in patients after anesthesia treatment. Among them, tau protein is a sensitive biomarker of neurodegenerative diseases, and the fluctuations in tau proteins are highly associated with various diseases. Furthermore, researchers have found unstable levels of tau protein after the anesthesia process. The current research has focused on quantifying tau protein via impedance spectroscopy to identify the problems caused by anesthesia-related drugs. An impedance spectroscopy electrode was modified into a multiwalled carbon nanotube, and an amine-ended aptamer was then attached. This electrode surface was used to quantify the tau protein level and reached the detection limit of 1 fM. The determination coefficient was found to be y = 369.93x + 1144.9, with R2 = 0.9846 in the linear range of 1 fM-1 nM. Furthermore, tau protein spiked human serum was clearly identified on the immobilized aptamer surface, indicating the specific detection.

Aggregation-induced enhanced emission-type cruciform luminophore constructed by carbazole exhibiting mechanical force-induced luminescent enhancement and chromism.

One D-A type cruciform luminophore MDCS-BC based on carbazole has been prepared. We observed that this compound exhibits unique intramolecular charge-transfer (ICT) and typical aggregation-induced enhanced emission (AIEE) properties with the solid-state luminescence efficiency of 0.184. Moreover, this luminophore shows a significant stimuli-induced emission enhancement and chromism effect with good reversibility. Upon grinding, the fluorescence color of the as-prepared samples can change from blue (454 nm) to green (504 nm). What is unexpected is that the fluorescence efficiency of the initial powder is dramatically increased from 0.184 to 0.424 upon grinding. The results of PXRD, DSC and spectral properties studies show that the mechanical force-induced luminescence enhancement and chromism behavior of MDCS-BC originates from the transition between crystal and amorphous morphology, and the large red-shift and the emission enhancement inducing by grinding may be attributed to the planarization of the molecular conformation and subsequent planar ICT process.

ß-Furan-Fused bis(Difluoroboron)-1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine Fluorescent Dyes in the Visible Deep-Red Region.

Novel ß-furan-fused bis(difluoroboron)-1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine (BOPHY) fluorescent dyes (F-BOPHY1-3) were prepared through an efficient process, and their structures were confirmed by (1)H NMR spectroscopy, (13)C NMR spectroscopy, MALDI-TOF HRMS, and element analysis. Their optical properties were then characterized by UV-vis absorption and photoluminescence (PL) spectroscopy. The UV-vis absorption and PL spectra of the dyes shifted to longer wavelengths relative to those of BOPHY because of the fusion of their furan rings, which extended π-conjugation of the molecules. All of the dyes exhibited large extinction coefficients (109700-12300 M(-1) cm(-1)), deep-red fluorescence emission (646-667 nm), moderate fluorescence quantum yields (0.30-0.45), as well as high chemical stability and photostability in solution. These advantageous properties show that these compounds are important to the design of efficient long-wavelength fluorescent dyes and are suitable for various applications in biotechnology and materials science.

Luminescent organic 1D nanomaterials based on bis(ß-diketone)carbazole derivatives.

A series of new triphenylamine-functionalized bis(ß-diketone)s bridged by a carbazole (CnBDKC, n=1, 4, 8, 16) with twisted intramolecular charge-transfer emission in polar solvents has been synthesized. The length of the carbon chains has a significant effect on the self-assembling properties of the compounds. Well-defined 1D nanowires were easily generated from C1BDKC with a methyl group by a reprecipitation approach directed by π-stacking interaction, and the molecules packed into J-aggregates in the nanowires. In addition, 1D nanofibers based on C16BDKC bearing a long hexadecyl chain were prepared through the organogelation process, and H-aggregates were formed driven by the synergistic effect of π-stacking interaction and van der Waals force in the gel phase. C4BDKC and C8BDKC containing butyl and octyl side chains, respectively, cannot arrange into dispersed nanostructures, probably because π-π interaction between conjugated moieties might be disturbed by the interaction between the side chains, which is, however, not strong enough to dominate the self-assembling process. Notably, the nanowires based on C1BDKC and the gel nanofibers from C16BDKC can emit strong green light under irradiation, which suggests that these 1D nanomaterials may have potential applications in emitting materials as well as photonic devices.

New dendritic gelator bearing carbazole in each branching unit: selected response to fluoride ion in gel phase.

A new dendritic gelator with carbazole as the building block (HBCD) was synthesized. It was found that H-bonding between the amide groups and π-π interaction between the aromatic rings played predominant roles in the gel formation. Meanwhile, significant aggregation-induced emission enhancement was observed in the gel state due to the formation of J-aggregates and the restricted molecular motion. Notably, the gel state of HBCD can be destroyed upon addition of F(-), accompanied by fluorescence enhancement on account of the formation of N-HF(-), which could further lead to the increased coplanarity of HBCD. The sensory capability of HBCD exhibited a high selectivity towards F(-) instead of the Cl(-), Br(-), I(-) and AcO(-) anions, which could be explained by the fact that the steric hindrance of the dendrimer would go against the interactions between the larger anions and HBCD.

Organogel based on ß-diketone-boron difluoride without alkyl chain and H-bonding unit directed by optimally balanced π-π interaction.

Rigid boomerang shaped triphenylamine functionalized bis-ß-diketone-boron difluoride without alkyl chain and H-bonding unit exhibits good gelation ability in some mixed organic solvents directed by optimally balanced π-π interactions.

Multicolor fluorescent switches in gel systems controlled by alkoxyl chain and solvent.

Two simple molecules, 1 and 2 with D-pi-A structure and alkoxyl groups, respectively, were designed and synthesized. Both compounds can gelatinize THF-water and DMSO. And compound 2 forms gel in acetone by ultrasonic stimulus. Interestingly, these gels exhibit aggregation-induced emission (AIE) during the sol-gel phase transformation. Moreover, the molecular self-assembled and photophysical properties can be controlled by the number of the alkoxyl chains and the type of the solvents. For example, 1 has an identical packing model and fluorescent colour in THF-water and DMSO gels. Contrarily, the self-assembly of molecule 2 strongly depends on the solvent. Furthermore, the gel phases of 2 formed in three solvents possess different fluorescent colours. Such as, THF-water gel emits yellow fluorescence, acetone gel has orange emission and red fluorescence appears in DMSO.

Hybrid self-assembly of a pi gelator and fullerene derivative with photoinduced electron transfer for photocurrent generation.

A pi-conjugated organogelator (1) was synthesized, and its gelation ability was checked. It was found that it is an excellent gelator for some organic solvents, such as dichloromethane, benzene, o-dichlorobenzene, and DMSO/water. It can self-assemble into 1-D nanofibers induced by hydrogen bonding and pi-pi interactions. Moreover, 1 could form a hybrid gel with C(60)COOH by hydrogen bonds in which 1 and C(60)COOH can act as an electron donor and acceptor, respectively. It was found that the active film from the hybrid 1-D self-assemblies of 1 and C(60)COOH showed remarkably higher photocurrent generation compared with that containing 1 and C(60) because of the construction of interdigitated and ordered assemblies of donors and acceptors.

Self-assembly of a chiral lipid gelator controlled by solvent and speed of gelation.

Glutamine derivative 1 with two-photon absorbing units has been synthesized and was found to show gelation ability in some solvents. Its self-assembly in the gel phase could be controlled by the solvent and speed of gelation. For example, in DMSO the organogelator self-assembled into H-aggregates with weak exciton coupling between the aromatic moieties. On the other hand, in DMSO/diphenyl ether (1:9, v/v) the molecules formed 1D aggregates, but with strong exciton coupling due to the small distance between the chromophores. Moreover, the formation of these two kinds of aggregates could be adjusted by the ratio of DMSO to diphenyl ether. In DMSO/toluene, DMSO/butanol, DMSO/butyl acetate, and DMSO/acetic acid systems similar results were observed. Therefore, conversion of the packing model occurs irrespective of the nature of the solvent. Notably, a unique sign inversion in the CD spectra could be realized by controlling the speed of gelation in the DMSO/diphenyl ether (1:9, v/v) system. It was found that a low speed of gelation induces the gelator to adopt a packing model with strong pi-pi interactions between the aromatic units. Moreover, the gels, when excited at 800 nm, emit strong green fluorescence and the quantum chemical calculations suggest that intramolecular charge transfer leads to two-photon absorption of the gelator molecule.

Carbazole-based organogel as a scaffold to construct energy transfer arrays with controllable fluorescence emission.

A diaryldiketopyrrolopyrrole derivative functionalized with phenothiazine moieties (DPPP) was synthesized and introduced into the ordered 4-(3,6-di-tert-butyl-9H-carbazol-9-yl)benzamide (TBCB) organogel system. It was found that TBCB-based gel became a scaffold to make DPPP molecules line up along the gel fibers, resulting in new self-assembled arrays, whose XRD patterns were quite different from those of the neat TBCB gel and DPPP crystal. In the composite gel, the occurrence of a partial energy transfer from the excited light-harvesting antenna of TBCB to the DPPP acceptor was confirmed on the basis of time-dependent and time-resolved fluorescence investigations. Remarkably, the composite gel could emit intense red light or purplish white light by tuning the excitation wavelength. Such ordered soft materials with color-tunable emission may possess potential applications in sensor and photonic devices.