Parallel peptide synthesis on microfluidic microarrays for identification of protein and cell binding ligands.

Advances in combinatorial chemistry have enabled the application of small molecule microarrays for study of limitless receptor-ligand interactions. Short synthetic peptides have emerged as popular probes for microarrays due to their stability, diverse range of biomolecular interactions and sequence specific bioactivity. Consequently, there is an increasing potential for spatially addressable peptide libraries, with high synthesis efficiencies and which are routinely producible at low cost and less time. In addition, the potential of peptide microarray applications has not yet been realized; with a relatively unexplored application of identification of synthetic peptides that target tumor cells. In this work, we present the development of an integrated parallel peptide synthesis system using solid phase peptide synthesis and photogenerated acid chemistry. Next we demonstrate the application of arrays synthesized by this system to the identification of cell and protein adhesive ligands. The surface of a silicon-glass microchip was modified to form a mixed self-assembled monolayer that presented PEG moieties interspersed with reactive amino terminals. The PEG provided biomolecular inertness and the reactive amino groups were used for consequent peptide synthesis. The cytophobicity of the surface was characterized by on-chip fluorescent binding assays and was found to be resistant to non-specific attachment of cells and proteins. An integrated system for parallel peptide synthesis on this reactive amino surface was developed, using photogenerated acid chemistry and digital microlithography. A constant synthesis efficiency of >98% was observed for up to 7mer peptides. To demonstrate specific cell adhesion on these synthetic peptide arrays, variations of a 7mer cell binding peptide that binds to murine B lymphoma cells were synthesized. Sequence specific binding was observed on incubation with fluorescently labeled, intact murine B lymphoma cells and key residues for binding were identified by deletional analysis. In conclusion, a combination of PEG-based surface passivation techniques and spatially addressable solid phase peptide synthesis was used to develop a highly specific cell-peptide adhesion assay on a microfluidic platform.Ph.D.Applied SciencesChemical engineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/126503/2/3253349.pd

New iridoid glucoside from <i>Picrorhiza kurroa </i>Royle ex Benth.

1023-1025Picrorhiza kurroa Royle ex Benth, commonly known as kutki is used as a crude drug reported in Indian pharmacopoeia. Acetyl derivative of a new iridoid glucoside, picroside V (6-m-methoxybenzoyl catalpol) along with three known iridoid glucosides picroside I, picroside II and catalpol have been isolated from the roots of Picrorhiza kurroa Royle ex Benth

<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Bacopasaponin H: A pseudojujubogenin glycoside from <i>Bacopa monniera</i></span>

1802-1804A new dammarane-type pseudojujubogenin glycoside hacopasaponin H has been isolated from the reputed Indian medicinal plant Bacopa monniera and characterized as 3-O-[α-1-arabinopyranosyl] pseudojujubogenin by spectral and chemical studies

Micropatterned Fiber Scaffolds for Spatially Controlled Cell Adhesion

Because the local microstructure plays a pivotal role for many biological functions, a wide range of methods have been developed to design precisely engineered substrates for both fundamental biological studies and biotechnological applications. However, these techniques have been by-and-large limited to flat surfaces. Herein, we use electrohydrodynamic co-spinning to prepare biodegradable three-dimensional fiber scaffolds with precisely engineered, micrometre-scale patterns, wherein each fiber is comprised of two distinguishable compartments. When bicompartmental fiber scaffolds are modified via spatially controlled peptide immobilization, highly selective cell guidance at spatial resolutions (<10 µm), so far exclusively reserved for flat substrates, is achieved. Microstructured fiber scaffolds may have utility for a range of biotechnological applications including tissue engineering or cell-based assays.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64103/1/1638_ftp.pd

Allylic Hydroxylation Through Acid Catalysed Epoxy Ring Opening of Betulinic Acid Derivatives

Acid catalysed epoxy ring opening of several lupane type triterpenoids leads to unusual allylic hydroxylation. The reaction involves the formation of epoxide by m-chloroperbenzoic acid followed by the treatment of mineral acid. The simple methodology finds utility to introduce a hydroxyl function at the allylic position in these triterpenoids, which is otherwise quite difficult

Macromol. Rapid Commun. 19/2009

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64100/1/1597_ftp.pd

Ocular adverse effects of Topiramate: Two case reports

Topiramate, an antiepileptic drug is reported to cause various ocular adverse effects like acute onset myopia, glaucoma. Visual field defect is an uncommon, serious treatment emergent adverse effect. We are reporting two cases of suspected topiramate induced visual field defects

Therapeutic use of quercetin in the control of infection and anemia associated with visceral leishmaniasis

Flavonoids are a broad class of plant phenolics that are known to possess a well-established protective effect against membrane lipoperoxidative damages. Oxidative damage of erythrocytes has been implicated in the reduced survival of erythrocytes during leishmanial infection. This study reveals the efficacy of five naturally occurring flavonoids in arresting the development of anemia during the postinfection period. Among the compounds studied, quercetin was most successful in inhibiting the oxidation of proteins and lipids on the red cell membranes of infected animals. Apart from its antianemic property, quercetin also seemed to be highly potent in lowering the parasite load in the spleen. Combination therapy of quercetin with the antileishmanial drug stibanate produced a better decay of SOH in the erythrocytes of the infected animals compared to that induced by quercetin or drug treatment alone. Similar results were obtained in successful prevention of proteolytic degradation resulting in an aversion to early lysis of red cells after simultaneous treatment with quercetin and stibanate. Subsequent studies demonstrated the therapeutic efficacy of the combination treatment in the abatement of both anemia and parasitemia under the diseased conditio

Enhanced ionic conductivity in Ce0.8Sm0.2O1.9: Unique effect of calcium co-doping

In order to identify new oxide ion-conducting materials in the ceria family of oxides, the unique effect of co-doping is explored and a novel series of Ce0.8Sm0.2-xCaxO2-delta Compositions is identified that have enhanced properties compared to the singledoped Ce0.8Sm0.2O1.9 and Ce0.8Ca0.2O1.9 cornpositions. Moreover, the superior characteristics of the co-doped Ce0.8Sm0.2-xCaxO2-delta powders prepared by the mixed-fuel process aid in obtaining 98 % dense ceramics upon sintering at 1.200 degrees C for 6 h. Though a linear increase in conductivity is observed by replacing Sm with Ca, the composition with the maximum amount of Ca and the minimum amount of Sm exhibits a significant improvement in properties compared to the rest in the series. The composition Ce0.80Sm0.05Ca0.15O2-delta exhibits a conductivity as high as 1.22 x 10(-1) S cm-l at 700 degrees C with minimum activation energy (0.56 eV) and a superior chemical stability to reduction compared to any of the hitherto known (CaSm) compositions. The absence of Ce-III, confirmed both from X-ray photoelectron spectroscopy and X-ray absorption spectroscopy, strongly suggests that the observed increase in conductivity is solely due to the oxide ion conductivity and not due to the partial electronic contribution arising from the presence of Ce-III and Ce-IV. To conclude, the experimental results on the Ce0.8Sm0.2-xCaxO2-delta series underscore the unique effect of calcium co-doping in identifying a cost-effective new composition, with a remarkably high conductivity and enhanced chemical stability to reduction, for technological application

Fluorescence switching of quantum dot in quantum dot–porphyrin–cucurbit [7] uril assemblies

The fluorescence switching of alloy (Cd<SUB>1-x</SUB>Zn<SUB>x</SUB>S) quantum dot (QD) in the presence of porphyrin and cucurbit [7] uril has been demonstrated using steady-state and time-resolved spectroscopy. The assemblies of Cd<SUB>1-x</SUB>Zn<SUB>x</SUB>S QD, 5-(4-aminophenyl)-10,15,20-triphenyl-21H,23H-porphyrin (APTPP), have been prepared by electrostatically attaching the negatively charged QD with positively charged APTPP. The drastic photoluminescence (PL) quenching and the shortening of decay time of alloy QD in the presence of porphyrin indicate the efficient energy transfer from QD to porphyrin. It is interesting to note that the PL quenching varies with changing the alloy composition, which reveals that the quenching of QD luminescence by porphyrin could be used as a probe for detection of porphyrin. Furthermore, in the presence of cucurbit [7] uril, CB[7] acts as a receptor to bind the porphyrin (quencher) and restore the luminescence of the QD by preventing the energy transfer from QD to porphyrin. Encapsulation of APTPP molecules within CB[7] is confirmed by steady-state and time-resolved anisotropic spectroscopy. The turn off/on fluorescence of luminescent QD opens a new opportunity for designing a new optical-based sensor for bioapplications