Synthesis, characterization and applications of maghemite beads functionalized with rabbit antibodies.

Magnetic nanoparticles (NPs) have attracted great attention owing to their applications in the biomedical field. In the present work, maghemite (γFe2O3) NPs of 6.5 nm were prepared using a sonochemical method and used to prepare magnetic beads through silanization with 3-aminopropyltrimethoxysilane (APTS). Subsequently, amino groups in the resulting APTS-γFe2O3 beads were converted to carboxylic acid (CARB-γFe2O3) through the succinic anhydride reaction, as confirmed by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy and dynamic light scattering (DLS) measurements. The size of these beads was measured as 12 nm and their hydrodynamic diameter as 490 nm, using TEM analysis and DLS, respectively. The CARB-γFe2O3 beads were further functionalized by immobilizing rabbit antibodies on their surfaces; the immobilization was confirmed by flow cytometry and ionic strength. The samples were further characterized by Mössbauer spectroscopy and DC magnetization measurements. Studies on magnetic relaxivities showed that magnetic beads present great potential for application in MR imaging.

Biometria e parâmetros hematológicos em tartarugas da Amazônia de um criatório comercial de Rio Branco/AC / Biometric and haematological indices in turtles from the Amazon farm in Rio Branco/AC

Com o objetivo de definir os valores biométricos e quantificar parâmetros hematológicos como hematócrito, concentração de proteínas plasmáticas totais e leucócitos totais de tartarugas da espécie Podocnemis expansa, coletou-se um mililitro de sangue da veia femoral de 60 exemplares aparentemente saudáveis. Os animais obtidos do criatório particular, Estância Terra, localizado no estado do Acre, foram classificados em seis grupos de pesos diferentes. Durante a biometria, foram tomadas medidas de peso, comprimento e largura da carapaça e do plastrão, para as análises da correlação dos parâmetros de tamanho e massa corporal entre os indivíduos do mesmo grupo. Os valores observados indicaram que o grupo 06, que inclui os animais com massa acima de 26 kg, apresentou melhor correlação entre as massas individuais de cada animal (r = 0,97) Enquanto que, o grupo 02 (massa entre 21 e 25 kg) apresentou a pior correlação entre as massas (r = 0,34). O resultado da média total de hematócrito de todos os animais deste experimento foi de 10,56%. A concentração das proteínas plasmáticas totais foi de 3,69g dL-1, e a média de leucócitos totais foi de 51466,66µL. Estes parâmetros são considerados fora do padrão quando comparados com os valores encontrados em animais saudáveis da mesma espécie. Assim, este trabalho pode contribuir com informações sobre os dados biométricos e parâmetros hematológicos de P. expansa de cativeiro e demonstra a importância do monitoramento da sanidade dos animais em cativeiro, prevenindo manifestação de enfermidades que poderão pôr em risco a saúde de todo o plantel.(AU)

The aim of this study was defined the biometric values and quantify hematological parameters such as hematocrit, concentration of total plasma proteins and total leukocytes for Podocnemis expansa, we collect one milliliter of blood from the femoral vein of 60 specimens apparently healthy. The animals were collected from a private farm, Estancia Terra, located in Rio Branco in the state of Acre, and were classified into six groups of different weights. During the collection of biometric data, weight measurements were taken, and length and width of the carapace and plastron, for the analysis of correlation between the size parameters and body mass between individuals of the same group. The values observed indicate that the group 06, which includes animals with mass above 26kg, showed the best correlation between the individual masses of each animal (R = 0.97), while the group 02 (weight 21 to 25kg) showed the worst correlation between the mass (r = 0.34). The result of the overall average hematocrit of all animals of this experiment was 10.56%. The concentration of total plasma proteins was 3,69g DL-1 and the average total number of leukocytes was 51466,66µL. These parameters are considered abnormal when compared to the values found in healthy animals of the same species. This work contributes with information about biometric data and hematological parameters of P. expansa captivity and demonstrates the importance of monitoring health, preventing diseases that may endanger the health of all animals in the farm.(AU)

Photoacoustic investigation of maghemite-based nanocomposite.

Photoacoustic spectroscopy was used to investigate magnetic nanocomposites incorporating nanosized maghemite particles into styrene-divinylbenzene copolymer template. Typical photoacoustic features were observed in bands C, S and L in the wavelength region of 300-1000 nm. The relative intensity of band-C scaled with the nominal concentration of nanosized maghemite incorporated into the polymeric template whereas the lowest relative intensity of band-S was found in the sample in which the template polymerization took place in the presence of the highest polar-like reaction medium. X-ray diffraction and transmission electron microscopy were used to characterize the magnetic nanosized phase as maghemite, with average particle diameter of 6.9 nm (sample Est34), 7.0 nm (sample H30), and 7.9 nm (sample Em15).

Synthesis, characterization and magnetic properties of polymer-Fe3O4 nanocomposite.

The chemical stability of magnetic particles is of great importance for their applications in medicine and biotechnology. The most challenging problem in physics of disordered systems of magnetic nanoparticles is the investigation of their dynamic properties. The chemical coprecipitation process was used to synthesize spherical magnetite nanoparticles of 14 nm. The as-prepared magnetite nanoparticles have been aged in the matrix. Magnetic properties and aging effect were studied by Mössbauer spectroscopy at temperatures ranging from 77 to 300 K, and X-ray diffraction. At room temperature, the Mössbauer spectrum showed superparamagnetic behavior of the particles, while well-defined sextets were observed at 77K, indicating a blocked regime. The superparamagnetic magnetite nanoparticles can be used as microbead biosensors.

Photoacoustic spectroscopy study of Blepharocalyx salicifolius (Kunt) O. Berg.

Photoacoustic spectroscopy (PAS) has revolutionized the fields of biological, environmental, and agricultural sciences. It is a very simple, sensitive, and non-destructive technique that allows the determination of optical properties of bio-samples. The in vivo chlorophylls of the leaf have a recorded maximum absorption peak at 675 nm as against 665 nm of the in vitro chlorophylls. The intensity of purple pigmentation in leaves of Blepharocalyx salicifolius (Kunt) O. Berg, is inversely correlated to the soil moisture levels, leaf water content and leaf water potentials. The applicability of PAS to biological samples was discussed. It allows the validation of existing emission models which are important for atmospheric process. A portable device for photoacoustic spectroscopy of plants and other photosynthetic tissues, cells and organelles is provided. Further, there is provided a method to measure photosynthesis of such tissues, cells and organelles.