Elongation of the Fe–His Bond in the α Subunit Induced by Binding of the Allosteric Effector Bezafibrate to Hemoglobins

Human adult hemoglobin (HbA), possessing an α2β2 tetramer structure, efficiently transports oxygen from the lungs to the tissues. The oxygen affinity of HbA has been shown to be regulated by organic phosphates such as 2,3-bisphosphoglycerate (BPG). Bezafibrate (BZF) is also known to alter the oxygen affinity of HbA through a mechanism largely different from that of BPG. The interaction of HbA with BZF has been characterized by 1H NMR to elucidate the molecular mechanism responsible for the functional alteration of HbA. Paramagnetically shifted heme methyl proton signals of only the α subunit of met-azido HbA exhibited sizable downfield shifts in the presence of BZF. Since met-azido HbA exhibits the so-called thermal spin equilibrium between high and low spin states, the BZF-induced shift changes observed for the α signals can be attributed to an increase in the high spin contents in the subunit, possibly due to the elongation of the Fe–His bond

Single-Beam Optical Biosensing Based on Enzyme-Linked Laser Nanopolymerization of <i>o</i>‑Phenylenediamine

We report an innovative biosensing technique using a focused laser beam for the fabrication of a polymer nanostructure and the detection of its nanoscale growth. A nanoaggregate structure is formed by focusing a single beam of a continuous-wave (cw) green laser beam on an <i>o</i>-phenylenediamine (o-pD) solution dropped on a glass substrate. The backreflection intensity of the focused laser beam shows a temporal oscillation, whereas the size of the aggregate monotonously increases. Simple calculations based on the Fresnel equation qualitatively reproduce the experimental results, indicating that the backreflected laser oscillation occurs because of the interference between two beams reflected at the front and the back surfaces of the aggregate. Because the growth speed of the aggregate depends on light absorption by the oxidized o-PD, the backreflection oscillation curve can be used to monitor the oxidative reaction in the solution. We apply this phenomena to optical biosensing based on the oxidation of o-PD by the peroxidase enzyme reaction. A reliable quantification of glucose can be achieved by simply focusing a single laser beam and detecting its reflection intensity in a manner similar to the optical pickup unit of optical storage drives

Interference Localized Surface Plasmon Resonance Nanosensor Tailored for the Detection of Specific Biomolecular Interactions

In this paper, we present an innovative sensing nanomaterial for an interference localized surface plasmon resonance (iLSPR) sensor. The iLSPR is based on plasmonic gold nanoparticles with photonic thin-film multilayers of porous aluminum oxide (Al2O3) and aluminum (Al) on a substrate. With a controllable transparent Al2O3 layer and a highly reflective Al layer, our new nanomaterial was able to detect refractive index (RI) changes of the surrounding environment and the specific interaction of biomolecules including biotin and avidin, 5- fluorouracil (5-FU) and its antibody, anti-5-fluorouracil (anti 5-FU), when the iLSPR surfaces were biologically functionalized. Our model nanostructure will open the way to display the plasmonic properties of other noble metal nanoparticles and to develop other functionally similar nanosensors, which could then be expanded into multiarrays

BDNF localizes in the injured IAN.

Histological analysis of inferior alveolar nerve (IAN) injury experiments in rats after 14 days. Azan staining (A, B) and immunohistochemical stainings of BDNF (C-G, I) and trkB (H, J). (A, C, E, G, H) Unaffected region of IAN injury. (B, D, F, I, J) Regenerating IAN region after injury. Although unaffected IAN and peripheral bone tissues did not express BDNF (C, E, G), injured IAN (D, F) and active osteoblasts on the surface of newly formed bone (I) were immunopositive for BDNF. The osteoblast lineage cells surrounding newly formed bone were immunopositive for trkB (J). IAN; inferior alveolar nerve. Bars, 100 μm (A-F), 20 μm (G-J).</p

An Interference Localized Surface Plasmon Resonance Biosensor Based on the Photonic Structure of Au Nanoparticles and SiO₂/Si Multilayers

This paper presents the experimental and simulation analysis of an original nanostructure design constructed with plasmonic gold nanoparticles and photonic thin-film multilayers of silicon dioxide (500 nm in thickness) and silicon on a substrate. Our nanostructure substrate showed a high sensitivity for various refractive index RI solutions and a prominent capacity for functionalizing alkanethiol molecules on the gold surface and demonstrates great potential in the development of a microfluidic-based biosensor for monitoring biotin−avidin interactions in real-time

Versatile Micropatterning of Plasmonic Nanostructures by Visible Light Induced Electroless Silver Plating on Gold Nanoseeds

A versatile fabrication technique for plasmonic silver (Ag) nanostructures that uses visible light exposure for micropatterning and plasmon resonance tuning is presented. The surface of a glass substrate modified with gold (Au) nanoseeds by a thermal dewetting process was used as a Ag plating platform. When a solution containing silver nitrate and sodium citrate was dropped on the Au nanoseeds under visible light exposure, the plasmon-mediated reduction of Ag ions was induced on the Au nanoseeds to form Ag nanostructures. The plasmon resonance spectra of Ag nanostructures were examined by an absorption spectral measurement and a finite-difference time-domain (FDTD) simulation. Some examples of Ag nanostructure patterning were demonstrated by means of light exposure through a photomask, direct writing with a focused laser beam, and the interference between two laser beams. Surface enhanced Raman spectroscopy (SERS) of 4-aminothiophenol (4-ATP) was conducted with fabricated Ag nanostructures

Local BDNF promotes bone formation after osteotomy in the mandible.

Micro-computed tomography images in the osteotomy at day 28 in rat. (A) The area of osteotomy was indicated by arrow (A). Twenty-eight days after osteotomy, exogenous BDNF accelerated regeneration of the cortex and induced osteosclerotic changes in the surrounding cortical bones (A). (B) Buccal cortical bone areas around osteotomy injury within 1,800 μm2 were measured using graphics software. The bone area was significantly wider in BDNF treated group.</p

Sclerotic changes in alveolar bone after IAN injury.

<p>CT, X-ray and photographic images from patients of a post-extraction tooth cavity. (A) A thirty-five-year-old woman reported dysesthesia for a long period after the tooth extraction. Sclerotic changes were observed in the periphery of the alveolar bone (arrows). (B) A 46-year-old woman experienced dysesthesia, which increased in relation to the deformity of the mandibular canal. In both of these patients, the masses of traumatic neuroma located in the nerve lesion were detected later by surgical observation.</p

Local BDNF induces osteosclerotic changes to surrounding bones.

<p>Hematoxylin and eosin staining (A-L) and azan staining (K, L) on day 7 (A-D), day 14 (E-H) and day 28 (I-L) after osteotomy in rat. (C, D, G, H, K, L) Magnified views of square areas in A, B, E, F, I, J. Histological examination demonstrated that many resorption lacunae were observed on the bone surface at day 7 in the control group (C, arrow and square). In contrast, the cortical bone surface was smooth with few resorption lacunae in BDNF group (D). After day 14, active osteoblasts lined the surface of the BDNF-treated bone (H, arrow and square), although osteoblast differentiation was not prominent in control (G). At day 28, a number of complicated reversal lines were observed in the BDNF-treated bone, and active bone formation occurred not only on the outer surface of the cortical bone but also inside of the bone lacunae and bone marrow cavity as clearly demonstrated by azan staining (L, arrow and square). Bars, 1000 μm (A, B, E, F, I, J), 100 μm (C, D, G, H, K, L).</p

BDNF promotes activation of Akt signals in MC3T3-E1 cells.

<p>Western blot analysis (A) and immunocytochemical staining of Akt and pAkt (Ser473) (B) in MC3T3-E1 cells. (A) BDNF significantly increased the active form of Akt (pAkt) in MC3T3-E1 cells at 30 min. On the other hand, the phosphorylation of ERK was not affected by BDNF. (B) BDNF enhanced pAkt immunoreactivity in the cytoplasm. The nucleus is stained with DAPI (blue).</p