Hierarchical starch-based fibrous scaffold for bone tissue engineering applications

Fibrous structures mimicking the morphology of the natural extracellular matrix are considered promising scaffolds for tissue engineering. This work aims to develop a novel hierarchical starch-based scaffold. Such scaffolds were obtained by a combination of starch-polycaprolactone micro- and polycaprolactone nano-motifs, respectively produced by rapid prototyping (RP) and electrospinning techniques. Scanning electron microscopy (SEM) and micro-computed tomography analysis showed the successful fabrication of a multilayer scaffold composed of parallel aligned microfibres in a grid-like arrangement, intercalated by a mesh-like structure with randomly distributed nanofibres (NFM). Human osteoblast-like cells were dynamically seeded on the scaffolds, using spinner flasks, and cultured for 7 days under static conditions. SEM analysis showed predominant cell attachment and spreading on the nanofibre meshes, which enhanced cell retention at the bulk of the composed/hierarchical scaffolds. A significant increment in cell proliferation and osteoblastic activity, assessed by alkaline phosphatase quantification, was observed on the hierarchical fibrous scaffolds. These results support our hypothesis that the integration of nanoscale fibres into 3D rapid prototype scaffolds substantially improves their biological performance in bone tissue-engineering strategies.This work was partially supported by the European Integrated Project GENOSTEM (Grant No. LSH-STREP-CT-2003-503161) and the European Network of Excellence EXPERTISSUES (Grant No. NMP3-CT-2004-500283). We also acknowledge the Portuguese Foundation for Science and Technology for the project Naturally Nano (Grant No. POCI/EME/58982/2004) and a PhD grant to A. Martins (Grant No. SFRH/BD/24382/2005)

Performance of new gellan gum hydrogels combined with human articular chondrocytes for cartilage regeneration when subcutaneously implanted in nude mice

Gellan gum is a polysaccharide that has been recently proposed by our group for cartilage tissueengineering applications. It is commonly used in the food and pharmaceutical industry and has the ability to form stable gels without the use of harsh reagents. Gellan gum can function as a minimally invasive injectable system, gelling inside the body in situ under physiological conditions and efficiently adapting to the defect site. In this work, gellan gum hydrogels were combined with human articular chondrocytes (hACs) and were subcutaneously implanted in nude mice for 4 weeks. The implants were collected for histological (haematoxylin and eosin and Alcian blue staining), biochemical [dimethylmethylene blue (GAG) assay], molecular (real-time PCR analyses for collagen types I, II and X, aggrecan) and immunological analyses (immunolocalization of collagen types I and II). The results showed a homogeneous cell distribution and the typical round-shaped morphology of the chondrocytes within the matrix upon implantation. Proteoglycans synthesis was detected by Alcian blue staining and a statistically significant increase of proteoglycans content was measured with the GAG assay quantified from 1 to 4 weeks of implantation. Real-time PCR analyses showed a statistically significant upregulation of collagen type II and aggrecan levels in the same periods. The immunological assays suggest deposition of collagen type II along with some collagen type I. The overall data shows that gellan gum hydrogels adequately support the growth and ECM deposition of human articular chondrocytes when implanted subcutaneously in nude mice.J. T. Oliveira would like to acknowledge the Portuguese Foundation for Science and Technology (FCT) for his grant (SFP,H/BD17135/2004). The authors would like to thank the patients at Hospital de S. Marcos, Braga, Portugal, for the donation of the biological samples and the medical staff for their help and support. The authors would also like to thank the Institute for Health and Life Sciences (ICVS), University of Minho, Braga, Portugal, for allowing the use of their research facilities. This work was carried out under the scope of European NoE EXPERTISSUES (Project No. NMP3-CT-2004-500283) and partially supported by the European Project HIPPOCRATES (No. STRP 505758-1)

A Arte e a Saúde: Uma possibilidade de reflexão e educação

Trabalho apresentado no 31º SEURS - Seminário de Extensão Universitária da Região Sul, realizado em Florianópolis, SC, no período de 04 a 07 de agosto de 2013 - Universidade Federal de Santa Catarina.O presente trabalho tem por objetivo promover por meio da expressão artística, uma reflexão frente aos fatores que condicionam a violência e o uso de drogas na adolescência. A atividade que se pretende desenvolver trata-se de uma oficina que transcorrerá de forma interativa junto aos participantes do 31º Seminário de Extensão da Região Sul. Os temas abordados a partir da temática proposta, e incluirão atividades que desenvolvam a reflexão a cerca das questões de saúde, o uso de drogas e a violência urbana. Neste contexto, compreende-se que a partir destes momentos de expressões artísticas os participantes abrem espaço para uma nova forma de perceber o mundo, a vida e o cotidiano. Além de despertar a vontade de experenciar novas alternativas que possibilitem suas expressões críticas frente às dificuldades vivenciadas reafirmando seus papeis como sujeitos de opiniões, mesmo se tratando de jovens adolescentes

Amphiphilic beads as depots for sustained drug release integrated into fibrillar scaffolds

Native extracellular matrix (ECM) is a complex fibrous structure loaded with bioactive cues that affects the surrounding cells. A promising strategy to mimicking native tissue architecture for tissue engineering applications is to engineer fibrous scaffolds using electrospinning. By loading appropriate bioactive cues within these fibrous scaffolds, various cellular functions such as cell adhesion, proliferation and differentiation can be regulated. Here, we report on the encapsulation and sustained release of a model hydrophobic drug (dexamethasone (Dex)) within beaded fibrillar scaffold of poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT), a polyether-ester multiblock copolymer to direct differentiation of human mesenchymal stem cells (hMSCs). The amphiphilic beads act as depots for sustained drug release that is integrated into the fibrillar scaffolds. The entrapment of Dex within the beaded structure results in sustained release of the drug over the period of 28days. This is mainly attributed to the diffusion driven release of Dex from the amphiphilic electrospun scaffolds. In vitro results indicate that hMSCs cultured on Dex containing beaded fibrillar scaffolds exhibit an increase in osteogenic differentiation potential, as evidenced by increased alkaline phosphatase (ALP) activity, compared to the direct infusion of Dex in the culture medium. The formation of a mineralized matrix is also significantly enhanced due to the controlled Dex release from the fibrous scaffolds. This approach can be used to engineer scaffolds with appropriate chemical cues to direct tissue regenerationAKG, SMM, LM and AK conceived the idea and designed the experiments. AKG and SMM fabricated electrospun scaffolds and performed the structural (SEM, FTIR), mechanical, and in vitro studies. AAK and AKGperformedDex release study. AKGand AP performed thermal analysis. AKG analyzed experimental data. AKG, SMM, LMand AK wrote the manuscript. ADL and CvB provided the polymers and corrected the manuscript. AKK, AP, MG and RLR revised the paper. All authors discussed the results and commented on the manuscript. Authors would like to thank Shilpaa Mukundan, Poornima Kulkarni and Dr. Arghya Paul for help with image analysis, drug release modeling and technical discussion respectively. AKG would like to thank Prof. Robert Langer for access to equipment and acknowledge financial support from MIT Portugal Program (MPP-09Call-Langer-47). SMMthanks the Portuguese Foundation for Science and Technology (FCT) for the personal grant SFRH/BD/42968/2008 (MIT-Portugal Program). This research was funded by the office of Naval Research Young National Investigator Award (AK), the Presidential Early Career Award for Scientists and Engineers (PECASE) (AK), the NIH (EB009196; DE019024; EB007249; HL099073; AR057837), the National Science Foundation CAREER award (DMR 0847287; AK), and the Dutch Technology Foundation (STW # 11135; LM, CvB, and AD)

Atividade antimicrobiana do urucum, ácido fosfórico e Biomax D® contra Listeria monocytogenes em salsicha / Antimicrobial activity of urucum, phosphoric acidand and Biomax D® against Listeria monocytogenes in sausage

Os produtos cárneos são frequentemente identificados como responsáveis por surtos e casos de listeriose. Compostos naturais como, extratos de plantas e frutos podem apresentar atividade antimicrobiana contra Listeria monocytogenes.  O presente estudo teve como objetivo avaliar a atividade antilisterial do urucum e ácido fosfórico, compostos utilizados na etapa de tingimento da salsicha, bem como do Biomax D® (extrato de pomelo e ácido ascórbico). Inicialmente, avaliou-se atividade antimicrobiana in vitro do urucum, ácido fosfórico e Biomax D® contra L. monocytogenes. Os compostos demostraram atividade antilisterial, no entanto, quando incorporado em alimentos esta ação antimicrobiana pode ser influenciada pelos componentes da matriz alimentar.  Para isto, salsichas foram contaminadas com diferentes concentrações de L. monocytogens e submetidas aos  tratamentos: T1 -  2,0% de urucum; T2 – 1,5% de ácido fosfórico; T3 – 2,0% de urucum e 1,5% de ácido fosfórico; T4 – 5,0% de Biomax D®; T5 – 5,0% de Biomax D® e  2,0% de urucum; T6 – 5,0% de Biomax D® e 1,5% de ácido fosfórico; T7 – 5,0% de Biomax D®, 2,0% de urucum e 1,5% de ácido de ácido fosfórico e armazenadas a 4 °C por 10 dias. Nos tempos zero, 5 e 10 dias, as salsicha foram submetidas as contagens de Listeria spp. em ágar Oxford e por PCR confirmou-sea espécie L. monocytogenes. Verificou-se que o urucum, o ácido fosfórico e o Biomax D® quando aplicados individualmente ou em conjunto apresentam atividade antilisterial em salsichas. A etapa de tingimento da salsicha pode contribuir para o controle deste micro-organismo. Além disso, o Biomax D® é um antimicrobiano natural, com potencial de utilização em salsicha

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO