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We present an easy and effective method for the encapsulation of cells inside PEG-based hydrogel microstructures fabricated using photolithography. High-density arrays of three-dimensional microstructures were created on substrates using this method. Mammalian cells were encapsulated in cylindrical hydrogel microstructures of 600 and 50 micrometers in(More)
Primary hepatocytes are commonly used as liver surrogates in toxicology and tissue engineering fields, therefore, maintenance of functional hepatocytes in vitro is an important topic of investigation. This paper sought to characterize heparin-based hydrogel as a three-dimensional scaffold for hepatocyte culture. The primary rat hepatocytes were mixed with a(More)
The regulatory system of the lactose operon has been "modeled" by a set of mass action equations and conservation constraints which describe the system at equilibrium. A "base-set" of values of binding constants and total component concentrations has been assembled from the available experimental data, and the simultaneous equations solved by computer(More)
When solubilized in laurylmaltoside, cytochrome oxidases from beef heart and rat liver mitochondria exist as monodisperse populations that are stable, highly active, and have apparent molecular weights of 300,000 to 350,000, as measured by gel filtration. To determine whether these are monomeric (2 heme A, 2 Cu) or dimeric forms of the enzyme, we performed(More)
Organizing leukocytes into high-density arrays makes these cells amenable to rapid optical characterization and subsequent sorting, pointing to clinical and basic science applications. The present paper describes development of a cytometry platform for creating high-density leukocyte arrays and demonstrates retrieval of single cells from the array.(More)
The electrostatic assembly of nanocomposite thin films consisting of alternating layers of an organometallic redox polymer (RP) and oxidoreductase enzymes, glucose oxidase (GOX), lactate oxidase (LOX) and pyruvate oxidase (PYX), was investigated. Multilayer nanostructures were fabricated on gold surfaces by the deposition of an anionic self-assembled(More)
This paper describes a novel approach of controlling cell-surface interactions through an electrochemical "switching" of biointerfacial properties of optically transparent microelectrodes. The indium tin oxide (ITO) microelectrodes, fabricated on glass substrates, were modified with poly(ethylene glycol) (PEG) silane to make glass and ITO regions resistant(More)
The gene (coxII) encoding subunit II of Rhodobacter sphaeroides cytochrome c oxidase (cytochrome aa3) has been isolated by screening a genomic DNA library in phage lambda with a probe derived from coxII of Paracoccus denitrificans. A 2-kb fragment containing coxII DNA was subcloned into the phage M13mp18 and the sequence determined. The 2-kb insert contains(More)
Biosensors are of great significance because of their capability to resolve a potentially large number of analytical problems and challenges in very diverse areas such as defense, homeland security, agriculture and food safety, environmental monitoring, medicine, pharmacology, industry, etc. The expanding role of biosensing in society and a real-world(More)
The coxII/coxIII operon of Rhodobacter sphaeroides cytochrome c oxidase has been sequenced and characterized by insertional inactivation/complementation analysis. The organization of the genes in this locus (coxII.orf1.orf3.coxIII) is the same as that of the equivalent operon of Paracoccus denitrificans (ctaC.ctaB.ctaG.ctaE), but unlike that of other(More)