Embedded Ultrathin Cluster Electrodes for Long-Term Recordings in Deep Brain Centers.

Neural interfaces which allow long-term recordings in deep brain structures in awake freely moving animals have the potential of becoming highly valuable tools in neuroscience. However, the recording quality usually deteriorates over time, probably at least partly due to tissue reactions caused by injuries during implantation, and subsequently micro-forces due to a lack of mechanical compliance between the tissue and neural interface. To address this challenge, we developed a gelatin embedded neural interface comprising highly flexible electrodes and evaluated its long term recording properties.

Chroman-4-one and chromone based somatostatin β-turn mimetics.

A scaffold approach has been used to develop somatostatin β-turn mimetics based on chroman-4-one and chromone ring systems. Such derivatives could adopt conformations resembling type II or type II' β-turns. Side chain equivalents of the crucial Trp8 and Lys9 in somatostatin were introduced in the 2- and 8-positions of the scaffolds using efficient reactions.

Hydrophobic ion pairing of a minocycline/Ca(2+)/AOT complex for preparation of drug-loaded PLGA nanoparticles with improved sustained release.

Polymeric nanoparticles is an established and efficient means to achieve controlled release of drugs. Incorporation of minocycline, an antibiotic with anti-inflammatory and neuroprotective properties, into biodegradable nanoparticles may therefore provide an efficient means to combat foreign body reactions to implanted electrodes in the brain. However, minocycline is commonly associated with poor encapsulation efficiencies and/or fast release rates due to its high solubility in water.

An array of highly flexible electrodes with a tailored configuration locked by gelatin during implantation-initial evaluation in cortex cerebri of awake rats.

Background: A major challenge in the field of neural interfaces is to overcome the problem of poor stability of neuronal recordings, which impedes long-term studies of individual neurons in the brain. Conceivably, unstable recordings reflect relative movements between electrode and tissue. To address this challenge, we have developed a new ultra-flexible electrode array and evaluated its performance in awake non-restrained animals.

Inhibitors and promoters of tubulin polymerization: synthesis and biological evaluation of chalcones and related dienones as potential anticancer agents.

A series of dihalogenated chalcones and structurally related dienones were synthesized and evaluated for their antiproliferative activity in 10 different cancer cell lines and for their effect on microtubule assembly. All compounds showed cytotoxic activity, with IC(50) values in the 5-280 μM range depending on the chalcone structure and the cell line. Five of the compounds were found to be tubulin polymerization inhibitors.

2,6,8-Trisubstituted 3-hydroxychromone derivatives as fluorophores for live-cell imaging.

We present the synthesis and photophysical characterisation of a series of structurally diverse, fluorescent 2,6,8-trisubstituted 3-hydroxychromone derivatives with high fluorescence quantum yields and molar extinction coefficients. Two of these derivatives (9 and 10 a) have been studied as fluorophores for cellular imaging in HeLa cells and show excellent permeability and promising fluorescence properties in a cellular environment. In addition, we have demonstrated by photophysical characterisation of 3-isobutyroxychromone derivatives that esterification of the 3-hydroxyl group results in acceptable and useful fluorescence properties.

Synthesis of 2-alkyl-substituted chromone derivatives using microwave irradiation.

A base-promoted condensation between 2-hydroxyacetophenones and aliphatic aldehydes has been studied. The reaction has been optimized to afford 2-alkyl-substituted 4-chromanones in an efficient manner using microwave heating. Performing the reaction using diisopropylamine in EtOH at 170 degrees C for 1 h gave moderate to high yields (43-88%).

Efficient bioreduction of bicyclo[2.2.2]octane-2,5-dione and bicyclo[2.2.2]oct-7-ene-2,5-dione by genetically engineered Saccharomyces cerevisiae.

A screening of non-conventional yeast species and several Saccharomyces cerevisiae (baker's yeast) strains overexpressing known carbonyl reductases revealed the S. cerevisiae reductase encoded by YMR226c as highly efficient for the reduction of the diketones 1 and 2 to their corresponding hydroxyketones 3-6 (Scheme 1) in excellent enantiomeric excesses. Bioreduction of 1 using the genetically engineered yeast TMB4100, overexpressing YMR226c, resulted in >99% ee for hydroxyketone (+)-4 and 84-98% ee for (-)-3, depending on the degree of conversion.

Evaluation of two pairs of chiral stationary phases: effects from the length of the achiral spacers.

Two pairs of chiral stationary phases (CSPs) with different C(2)-symmetric central parts were prepared and evaluated by chromatography of a series of structurally different racemates. Within each pair, the selectors on which the CSPs are based had different lengths of their achiral spacers. The CSPs based on selectors with short spacers showed higher enantioselectivity than the phases incorporating long spacers.