Oil-Isolated Hydrogel Microstructures for Sensitive Bioassays On-Chip

Multiplexed, sensitive, and on-chip molecular diagnostic assays are essential in both clinical and research settings. In past work, running reactions in nanoliter- to femtoliter-sized volumes such as microwells or droplets has led to significant increases in detection sensitivities. At the same time, hydrogels have emerged as attractive scaffolds for bioassays due to their nonfouling, flexible, and aqueous properties. In this paper, we combine these concepts and develop a novel platform in which hydrogel compartments are used as individually confined reaction volumes within a fluorinated oil phase. We fabricate functional and versatile hydrogel microstructures in microfluidic channels that are physically isolated from each other using a surfactant-free fluorinated oil phase, generating picoliter- to nanoliter-sized immobilized aqueous reaction compartments that are readily functionalized with biomolecules. In doing so, we achieve monodisperse reaction volumes with an aqueous interior while exploiting the unique chemistry of a hydrogel, which provides a solid and porous binding scaffold for biomolecules and is impenetrable to oil. Furthermore, our lithographically defined reaction volumes are readily customized with respect to geometry and chemistry within the same channel, allowing rational tuning of the confined reaction volume on a post-to-post basis without needing to use surfactants to maintain stability. We design and implement a multiplexed signal amplification assay in which gel-bound enzymes turn over small molecule substrate into fluorescent product in the oil-confined gel compartment, providing significant signal enhancement. Using short (20 min) amplification times, the encapsulation scheme provides up to 2 orders of magnitude boost of signal in nucleic acid detection assays relative to direct labeling and does not suffer from any cross-talk between the posts. We ultimately demonstrate up to 57-fold increase in nucleic acid detection sensitivity compared to a direct labeling scheme.National Institutes of Health (U.S.). Center for Future Technologies in Cancer Care (U54-EB-015403-01)National Institutes of Health (U.S.) (Interdepartmental Biotechnology Training Grant T32 GM08334)National Science Foundation (U.S.) (Grant CMMI-1120724

Suppression of spermatogenesis before grafting increases survival and supports resurgence of spermatogenesis in adult mouse testis

Objective: To test whether absence of complete spermatogenesis in mature testicular tissue before grafting will increase graft survival. Design: Prospective experimental study. Setting: Laboratory. Animal(s): Donor testes were obtained from adult untreated mice, adult mice rendered cryptorchid, and adult mice treated with a GnRH antagonist (acyline). Intervention(s): Donor testes were ectopically grafted to nude mice and recovered at three time points. Main Outcome Measure(s): Most advanced germ cell type and presence of spermatogonia were assessed. Donor testes and grafts were analyzed by histology and by immunocytochemistry for ubiquitin C-terminal hydrolase-L1 to mark germ cells. Result(s): Suppression of spermatogenesis by inducing cryptorchidism or acyline treatment resulted in improved survival of grafted tissue compared with controls and recovery of complete spermatogenesis, whereas control testis grafts mostly degenerated and did not restore complete spermatogenesis. Conclusion(s): These results indicate that complete spermatogenesis at the time of grafting has a negative effect on graft survival. Grafting of adult testis tissue from donors with suppressed spermatogenesis leads to spermatogenic recovery and may provide a tool to study and preserve fertility and for conservation of genetic resources in individuals that lack complete germ cell differentiation. © 2012 American Society for Reproductive Medicine.Peer Reviewe

Sclerotinia rot of rapeseed mustard: A comprehensive review

Indian mustard [Brassica juncea (L.) Czern & Coss.] is one of the major oilseed crops cultivated in India and around the world. It is extensively grown traditionally as a pure crop as well as intercrop (mixed crop) in marginal and sub-marginal soils in the eastern, northern and north western states of India. Cool and moist climate of winter months is the major factor for luxuriant growth and productivity of mustard in these states. Despite considerable increase in productivity and production, a wide gap exists between yield potential and yield realized at farmer’s field, which is largely due to biotic and abiotic stresses. The destructive diseases of rapeseed-mustard include those caused by fungi, bacteria, viruses and phytoplasma. Among them, Sclerotinia stem rot is the most serious fungal disease that causes maximum damage in Indian mustard. This paper reviews the research and development of Sclerotinia rot in rapeseed-mustard during the past years in relation to pathogen taxonomy, biology, epidemiology, disease cycle and management. The paper also attempts to present future outlook and strategy for Sclerotinia rot of rapeseed mustard research

Prospects of III-Vs for Logic Applications

The increasing challenges for further scaling down of Si CMOS require the study of alternative channel materials. This paper highlights the significance of III-V compound semiconductor materials in order to face the looming fate of Si CMOS technology. The potential advantages of using III-Vs as channel materials for future III-V CMOS is its outstanding transport properties that have been widely accepted in high frequency RF applications. However, many significant challenges in front of III-V digital technology needs to be overcome before III-V CMOS becomes feasible for next generation high speed and low power logic applications. But it may be that this situation is changing given recent progress in the fabrication of high-mobility III-Vs based heterostructure electronic devices for logic applications to fulfill the needs towards the everyday evolving III-V CMOS technology. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2778

Hydrogel microparticles for biosensing

Due to their hydrophilic, biocompatible, and highly tunable nature, hydrogel materials have attracted strong interest in the recent years for numerous biotechnological applications. In particular, their solution-like environment and non-fouling nature in complex biological samples render hydrogels as ideal substrates for biosensing applications. Hydrogel coatings, and later, gel dot surface microarrays, were successfully used in sensitive nucleic acid assays and immunoassays. More recently, new microfabrication techniques for synthesizing encoded particles from hydrogel materials have enabled the development of hydrogel-based suspension arrays. Lithography processes and droplet-based microfluidic techniques enable generation of libraries of particles with unique spectral or graphical codes, for multiplexed sensing in biological samples. In this review, we discuss the key questions arising when designing hydrogel particles dedicated to biosensing. How can the hydrogel material be engineered in order to tune its properties and immobilize bioprobes inside? What are the strategies to fabricate and encode gel particles, and how can particles be processed and decoded after the assay? Finally, we review the bioassays reported so far in the literature that have used hydrogel particle arrays and give an outlook of further developments of the field. Keywords: Hydrogel; Biosensor; Microparticle; Multiplex assayNovartis Institutes of Biomedical Research (Presidential Fellowship)Novartis Institutes of Biomedical Research (Education Office)National Cancer Institute (U.S.) (Grant 5R21CA177393-02)National Science Foundation (U.S.) (Grant CMMI-1120724)Institute for Collaborative Biotechnologies (Grant W911NF-09-0001)United States. Army Research Offic

Phyto-mediated Synthesis of Copper Nanoparticles by Cassia auriculata and its Characterization with reference to E-waste Management

An eco-friendly loom has been taking up in the present study to synthesize copper nanoparticles using Cassia auriculata. The leaf extract of Cassia auriculata acts as reducing as well as capping agent. Synthesis of copper nanoparticles was initially confirmed by the visual observation i.e color change (dark green color). The synthesized copper nanoparticles were primarily characterized by UV-vis spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy. Further, the formation of amorphous and crystalline phase was analyzed by X-Ray Diffraction pattern. The size and morphology of the synthesized Copper nanoparticles was characterized by Scanning Electron Microscopy (SEM) and the elemental composition was analyzed by EDAX. The present study is a preliminary investigation to know about the capability of Cassia auriculata to synthesize copper nanoparticles from its salts. The results of the present study confirmed that the leaf extract of Cassia auriculata be capable of recovering copper from printed circuit boards in the form of nanoparticles in near future

Selection of Bradyrhizobium or Ensifer symbionts by the native Indian caesalpinioid legume Chamaecrista pumila depends on soil pH and other edaphic and climatic factors

Nodules of Chamaecrista pumila growing in several locations in India were sampled for anatomical studies and for characterization of their rhizobial microsymbionts. Regardless of their region of origin, the nodules were indeterminate with their bacteroids contained within symbiosomes which were surrounded by pectin. More than 150 strains were isolated from alkaline soils from the Thar Desert (Rajasthan), wet-acidic soils of Shillong (Meghalaya), and from trap experiments using soils from four other states with different agro-ecological regions. Molecular phylogenetic analysis based on five housekeeping (rrs, recA, glnII, dnaK, atpD) and two symbiotic (nodA, nifH) genes was done for selected strains. Chamaecrista pumila was shown to be nodulated by niche-specific diverse strains of either Ensifer or Bradyrhizobium in alkaline (Thar Desert) to neutral (Tamil Nadu) soils and only Bradyrhizobium strains in acidic (Shillong) soils. Concatenated core gene phylogenies showed four novel Ensifer-MLSA types and nine Bradyrhizobium-MLSA types. Genetically diverse Ensifer strains harbored similar sym genes which were novel. In contrast, significant symbiotic diversity was observed in the Bradyrhizobium strains. The C. pumila strains cross-nodulated Vigna radiata and some wild papilionoid and mimosoid legumes. It is suggested that soil pH and moisture level played important roles in structuring the C. pumila microsymbiont community.</p