Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30536 (PBS)
 9,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thin polymer films with the ability of both drug release and protein adsorption resistance were formed on silicon substrates and silica particles. The films were made of a block copolymer of poly(N-isopropylacrylamide) (p(AAm)) that can load and release drugs and poly(2-methoxyethyl methacrylate) (p(MEMA)) that can suppress protein adsorption. Aspirin and bovine serum albumin were respectively used as model substances for testing the abilities of the films to load and release drugs and to suppress protein adsorption. The films were immersed in a phosphate buffer saline (pH 7.4) for 100 days to evaluate their water resistance. The experimental results showed that the films have both drug release and protein adsorption resistance and are highly stable against PBS.
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PMID:Preparation of thin polymer films with drug release and protein adsorption resistance. 1716 91

The objective of this study was to determine whether stromal and/or epithelial relaxin receptor (LGR7) is required for relaxin to promote proliferation and inhibit apoptosis of stromal and epithelial cells in the mouse cervix and vagina. Tissue recombinants were prepared with stroma (St) and epithelium (Ep) from wild-type (wt) and LGR7 knockout (ko) mice: wt-St+wt-Ep, wt-St+ko-Ep, ko-St+wt-Ep, and ko-St+ko-Ep. Tissue recombinants were grafted under the renal capsule of intact syngeneic female mice. After 3 wk of transplant growth, hosts were ovariectomized and fitted with silicon implants containing progesterone and estradiol-17beta (designated d 1 of treatment). Animals were injected sc with relaxin or relaxin vehicle PBS at 6-h intervals from 0600 h on d 8 through 0600 h on d 10 of treatment. To evaluate cell proliferation, 5-bromo-2'-deoxyuridine was injected sc 10 h before cervices and vaginas were collected at 1000 h on d 10. Terminal deoxynucleotidyl transferase-mediated deoxyuridine 5'-triphosphate nick end labeling was used to quantify apoptosis. Relaxin markedly increased proliferation and decreased apoptosis of epithelial and stromal cells in tissue recombinants containing wt stroma (P < 0.01) but had no effect on tissue recombinants prepared with ko stroma, regardless of whether epithelium was derived from wt or ko mice. In conclusion, this study shows that LGR7-expressing cells in the stroma are both necessary and sufficient for relaxin to promote proliferation and inhibit apoptosis in both stromal and epithelial cells of cervix and vagina, whereas epithelial LGR7 does not affect these processes.
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PMID:Relaxin acts on stromal cells to promote epithelial and stromal proliferation and inhibit apoptosis in the mouse cervix and vagina. 1821 91

A silicon nanowire-based sensor for biological application showed highly desirable electrical responses to either pH changes or receptor-ligand interactions such as protein disease markers, viruses, and DNA hybridization. Furthermore, because the silicon nanowire can display results in real-time, it may possess superior characteristics for biosensing than those demonstrated in previously studied methods. However, despite its promising potential and advantages, certain process-related limitations of the device, due to its size and material characteristics, need to be addressed. In this article, we suggest possible solutions. We fabricated silicon nanowire using a top-down and low cost micromachining method, and evaluate the sensing of molecules after transfer and surface modifications. Our newly designed method can be used to attach highly ordered nanowires to various substrates, to form a nanowire array device, which needs to follow a series of repetitive steps in conventional fabrication technology based on a vapor-liquid-solid (VLS) method. For evaluation, we demonstrated that our newly fabricated silicon nanowire arrays could detect pH changes as well as streptavidin-biotin binding events. As well as the initial proof-of-principle studies, C-reactive protein binding was measured: electrical signals were changed in a linear fashion with the concentration (1 fM to 1 nM) in PBS containing 1.37 mM of salts. Finally, to address the effects of Debye length, silicon nanowires coupled with antigen proteins underwent electrical signal changes as the salt concentration changed.
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PMID:Quantitative measurements of C-reactive protein using silicon nanowire arrays. 1848 22

Biotin/silole-derivatized distributed Bragg reflectors porous silicon (DBR PSi) smart particles for the detection of streptavidin have been developed. DBR PSi fabricated by applying a computer-controlled periodic square current waveform was prepared for the application as a label-free biosensor based on PSi interferometer. The fabrication, optical characterization, and surface derivatization of DBR smart particles were described. Biotin/silole-derivatized DBR smart particles displaying dual optical properties such as photoluminescence (lambda(em) = 505 nm) and reflectivity (lambda(max) = 607 nm) were obtained from the DBR PSi film in organic solution by using ultra-sono method. The surface and cross sectional morphology of DBR smart particles were obtained with FE-SEM. FT-IR spectroscopy was used to characterize the oxidation and functionalization of DBR smart particles. Binding of the streptavidin into the biotin-derivatized DBR smart particles displayed a change in refractive index. A red-shift of reflectivity by 14 nm in the reflectivity spectrum was observed, when the biotin-modified DBR smart particles were exposed to a flow of PBS buffer solution containing streptavidin.
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PMID:Fabrication and characterization of surface-derivatized porous silicon "smart particles" for detection of streptavidin. 1919 13

We have measured the influence of mesoporous silica (MCM-41 and SBA-15) nanoparticles and dense silica nanoparticles on epinephrine oxidation, a pH-dependent reaction, whose rate is small in acidic or neutral solutions but much greater at higher pH. The reaction was measured by monitoring adrenochrome at 480 nm, the product of epinephrine oxidation. In distilled water (dH(2)O) with no particles present, the oxidation of epinephrine occurs slowly but more rapidly at higher pH. The presence of MCM-41 or silica spheres does not accelerate the oxidation, but SBA-15 does, showing that the difference in the structures of nanomaterials leads to differing effects on the epinephrine oxidative process. In phosphate buffered saline (PBS, pH = 7.4), epinephrine undergoes a much quicker oxidation, and, in this case, the presence of SBA-15 and MCM-41 makes it even more rapid. Silica spheres have no noticeable influence on the oxidation in PBS or in dH(2)O. The possibility that the catalytic effect of mesoporous silica nanoparticles (MSN) could result from the residue of templating chemicals, however, can be excluded due to the postsynthesis calcinations. Experiments with dithionite, added either earlier than or at the same time as the epinephrine addition, show that fast oxidation takes place only when dithionite and epinephrine are simultaneously added into PBS solution. This confirms a vital role of oxygen radicals (probably *O(2)(-)) in the oxidation of epinephrine. These oxygen radicals are likely to form and accumulate within the phosphate buffer or in the presence of MSN. Comparing the three kinds of silica nanoparticles applied, we note that mesoporous SBA-15 and MCM-41 materials own much larger surface area than solid silica particles do, whereas MCM-41 possesses a much narrower pore size (0.4-fold) than SBA-15. It seems, therefore, that large surface area, characteristic mesoporosity, and surface structures aid in the deposit of oxygen radicals inside MSN particles, which catalyze the epinephrine oxidation in a favorable phosphate environment.
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PMID:Accelerated oxidation of epinephrine by silica nanoparticles. 1946 13

Cell and tissue responses to implanted biomaterials often limit their effectiveness and lifetime. This is particularly true for materials implanted into the brain. We present here a new approach for the modification of materials to enable release of multiple agents, which might be useful in modulating tissue responses, without changing the properties of the underlying material, in this case, a silicon probe. Poly(lactide-co-glycolide) nanoparticles (NPs) were assembled onto silicon probe surfaces by electrostatic interactions. Charged NPs were fabricated by altering the properties of the surfactant. NPs formed with poly(ethylene-alt-maleic anhydride) (PEMA) were strongly negatively charged; these NPs assembled onto probes best when suspended at nearly physiological conditions (surface density approximately 83,600+/-3000 particles/mm(2)). The percentage of surface area coverage by the NPs was estimated to be approximately 13% and was maintained over two weeks during constant exposure to PBS. Multiple fluorescent NP populations were attached to the same probe to allow visualization of simultaneous delivery of multiple agents by fluorescence microscopy. Release from NP coatings was reproducible and controllable. The distinct release profiles of each agent from the coatings were preserved upon attachment to the surfaces. The unique feature of this new system is that NPs encapsulating various molecules (i.e. drugs, proteins, or DNA) can be fabricated separately, in advance, and simply mixed prior to attachment. The versatility of this delivery system, therefore, makes it suitable for many applications.
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PMID:Simultaneous release of multiple molecules from poly(lactide-co-glycolide) nanoparticles assembled onto medical devices. 1959 89

Fixation of ferritin using amino-silane modified substrates is effective, but salt and alkali ions of the buffer can contaminate substrates, inhibiting the sensing and fabrication of nano-electronic devices. To avoid adsorption of salts and alkali ions, buffer solutions have been replaced by pure water or alkali-metal-ion-free buffer. However, proteins in such solutions are sometimes denatured. Therefore, we developed a substrate which adsorbs ferritin but does not adsorb contaminants such as salts and alkali metal-ions contained in the buffer. Adsorption of ferritin was achieved by using a buffer with a high ion strength, such as PBS buffer, because the Debye length becomes shorter with increased ion strength due to intermolecular force even when the substrate has no positive charge. The combination of high coverage methyltrimethoxysilane (MTMS)-coupled silicon substrate and PBS buffer solution is effective for adsorption of ferritin while not adsorbing buffer components such as contaminants and/or salts on the silicon substrate.
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PMID:Adsorption behavior of ferritin and buffer components, buffer agents and salts, onto silane-coupled silicon substrate. 1978 20

The authors synthesized a kind of upconversion nanocrystals NaYF4:Yb3+, Er3+ via the hydrothermal assisted homogeneous precipitation method, and then the nanocrystal was coated with silica. The SEM image demonstrated that the as-prepared samples were uniform in size distribution with ca. 25 nm before and ca. 250 nm after silica coating, respectively. The upconversion spectra and photoluminescence lifetime measurement showed that the silica shell had hardly effect on the properties of fluorescence of the NaYF4:Yb3+, Er3+ nanocrystals. At the same time, the naked eye-visible green upconversion fluorescence pattern was acquired from the as-prepared upconversion nanoparticles in the PBS buffer (2 wt%) excited by 980 nm laser at room temperature. These water-soluble nanoparticles were linked to the antibodies using the coupling reagents glutaraldehyde. The circular dichroism (CD) spectra of antibody and upconversion nanoparticles-antibody conjugates were very similar to each other, indicating that the secondary structure of antibody remained largely intact after the conjugation. Finally, antigen-antibody recognition reaction was performed on the surface of a silicon slide. The immunofluorescence in vitro indicated that the upconversion nanoparticles-antibody bioconjugates had excellent species-specific detection ability with hardly non-specific binding. Based on the present results, it is anticipated that the silica-coated upconversion nanoparticles are suitable for use as biolabeling materials.
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PMID:[Preparation, characterization and specific biological labeling of silica coated upconversion fluorescent nanocrystals]. 2030 99

The study objective was to determine whether stromal and/or epithelial estrogen receptor-alpha (ERalpha) is required for relaxin to promote proliferation of stromal and epithelial cells in the mouse cervix. Four types of tissue recombinants were prepared with cervical stroma (St) and epithelium (Ep) from wild-type (wt) and ERalpha knockout (ko) mice: wt-St+wt-Ep, wt-St+ko-Ep, ko-St+wt-Ep and ko-St+ko-Ep. Tissue recombinants were grafted under the renal capsule of syngeneic female mice. After 3 wk of transplant growth, hosts were ovariectomized and fitted with silicon implants containing 17beta-estradiol (treatment d 1). Animals were injected sc with relaxin or vehicle PBS at 6-h intervals from 0600 h on d 8 through 0600 h on d 10. To evaluate cell proliferation, 5-bromo-2'-deoxyuridine was injected sc 10 h before tissue recombinants were collected at 1000 h on d 10. Relaxin promoted marked proliferation of both epithelial and stromal cells in tissue recombinants containing wt St (P < 0.001) but far lower proliferation in recombinants prepared with ko St, regardless of whether Ep was derived from wt or ko mice. An additional experiment using mice expressing wt ERalpha, a mutant of ERalpha that selectively lacks classical signaling through estrogen response element binding, or no ERalpha demonstrated that ERalpha must bind to an estrogen response element to enable relaxin's proliferative effects. In conclusion, this study shows that ERalpha-expressing cells in St, using a classical signaling pathway, are necessary for relaxin to promote marked proliferation in both stromal and epithelial cells of the mouse cervix.
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PMID:The effect of relaxin on cell proliferation in mouse cervix requires estrogen receptor {alpha} binding to estrogen response elements in stromal cells. 2030 31

Thin films terminated with oligo(ethylene glycol) (OEG) could be photochemically grafted onto ultrathin silicon carbide layers that were generated on silicon substrates via carbonization with acetylene at 820 degrees C. The OEG coating reduced the non-specific adsorption of fibrinogen on the substrates by 99.5% and remained resistant after storage in PBS for 4 weeks at 37 degrees C.
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PMID:Highly stable, protein resistant thin films on SiC-modified silicon substrates. 2044 89


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