pinecone/core-2020-05-10-deduplication huggingface dataset:
Depth-resolved multimodal imaging : wavelength modulated spatially offset Raman spectroscopy with optical coherence tomography

Funding: UK Engineering and Physical Sciences Research Council (EPSRC: EP/J01771X/1, EP/M000869/1), the European Union FAMOS project (FP7 ICT, 317744) and the RS MacDonald Charitable Trust for funding.A major challenge in biophotonics is multimodal imaging to obtain both morphological and molecular information at depth. We demonstrate a hybrid approach integrating optical coherence tomography (OCT) with wavelength modulated spatially offset Raman spectroscopy (WM-SORS). With depth co-localization obtained from the OCT, we can penetrate 1.2mm deep into the strong scattering media (lard) to acquire up to a 14-fold enhancement of a Raman signal from a hidden target (Polystyrene) with a spatial offset. Our approach is also capable of detecting both Raman and OCT signals for pharmaceutical particles embedded in turbid media and revealing the white matter within a brain tissue layer. This depth resolved label-free multimodal approach is a powerful route to analyze complex biomedical samples.PostprintPeer reviewe
3D correlative single-cell imaging utilizing fluorescence and refractive
  index tomography

Cells alter the path of light, a fact that leads to well-known aberrations in
single cell or tissue imaging. Optical diffraction tomography (ODT) measures
the biophysical property that causes these aberrations, the refractive index
(RI). ODT is complementary to fluorescence imaging and does not require any
markers. The present study introduces RI and fluorescence tomography with
optofluidic rotation (RAFTOR) of suspended cells, quantifying the intracellular
RI distribution and colocalizing it with fluorescence in 3D. The technique is
validated with cell phantoms and used to confirm a lower nuclear RI for HL60
cells. Furthermore, the nuclear inversion of adult mouse photoreceptor cells is
observed in the RI distribution. The applications shown confirm predictions of
previous studies and illustrate the potential of RAFTOR to improve our
understanding of cells and tissues.Comment: 15 pages, 5 figure
In situ study of partially crystallized bioglass (R) and hydroxylapatite in vitro bioactivity using atomic force microscopy

The present work investigates, in situ, the in vitro
bioactivity of partially crystallized 45S5 Bioglass! (BG) as a
function of immersion time in a simulated body fluid (SBF)
using atomic force microscopy (AFM). The results obtained
for the crystallized BG! were compared to those of hydroxyapatite
c- and a-faces. The calcium phosphate layer grows on
the crystallized 45S5 B! by multiple two-dimensional nucleation
and fusion of these two-dimensional islands, which is
essentially the same mode as for the hydroxyapatite c-face.
The surface of the crystallized 45S5 BG! was almost fully
covered with a dense and compact calcium phosphate layer
after 24 h. The calcium phosphate formation on the crystallized
BG! arises from a low surface energy of the surface
layer and/or an effect of the layer to lower the resistance
when the growth units of calcium phosphate incorporate
into the growing island. These results indicate that the crystallized
45S5 BG! is suitable to be used as a filler for polymeric
matrix bioactive composites, as it maintains a high
bioactivity associated with a stiffer behavior (as compared to
standard BG!)
Effect of flow perfusion on the osteogenic differentiation of bone marrow stromal cells cultured on starch-based three dimensional scaffolds

This study aims to investigate the effect of culturing conditions (static and flow perfusion) on the proliferation and osteogenic differentiation of rat bone marrow stromal cells seeded on two novel scaffolds exhibiting distinct porous structures. Specifically, scaffolds based on SEVA-C (a blend of starch with ethylene vinyl alcohol) and SPCL (a blend of starch with polycaprolactone) were examined in static and flow perfusion culture. SEVA-C scaffolds were formed using an extrusion process, whereas SPCL scaffolds were obtained by a fiber bonding process. For this purpose, these scaffolds were seeded with marrow stromal cells harvested from femoras and tibias of Wistar rats and cultured in a flow perfusion bioreactor and in 6-well plates for 3, 7, and 15 days. The proliferation and alkaline phosphatase activity patterns were similar for both types of scaffolds and for both culture conditions. However, calcium content analysis revealed a significant enhancement of calcium deposition on both scaffold types cultured under flow perfusion. This observation was confirmed by Von Kossa-stained sections and tetracycline fluorescence. Histological analysis and confocal images of the cultured scaffolds showed a much better distribution of cells within the SPCL scaffolds than the SEVA-C scaffolds, which had limited pore interconnectivity, under flow perfusion conditions. In the scaffolds cultured under static conditions, only a surface layer of cells was observed. These results suggest that flow perfusion culture enhances the osteogenic differentiation of marrow stromal cells and improves their distribution in three-dimensional, starch-based scaffolds. They also indicate that scaffold architecture and especially pore interconnectivity affect the homogeneity of the formed tissueFundação para a Ciência e a Tecnologia  (FCT
Casein and soybean protein-based thermoplastics and composites as alternative biodegradable polymers for biomedical applications

This work reports on the development and characterization of novel meltable polymers and composites based on casein and soybean proteins. The effects of inert (Al(2)O(3)) and bioactive (tricalcium phosphate) ceramic reinforcements over the mechanical performance, water absorption, and ioactivity behavior of the injection-molded thermoplastics were examined. It was possible to obtain materials and composites with a range of mechanical properties, which might allow for their application in the biomedical field. The incorporation of tricalcium phosphate into the soybean thermoplastic decreased its mechanical properties but lead to the nucleation of a bioactive calcium-phosphate film on their surface when immersed in a simulated body fluid solution. When compounded with 1% of a zirconate coupling agent, the nucleation and growth of the bioactive films on the surface of the referred to composites was accelerated. The materials degradation was studied for ageing periods up to 60 days in an isotonic saline solution. Both water uptake and weight loss were monitored as a function of the immersion time. After 1 month of immersion, the materials showed signal of chemical degradation, presenting weight losses up to 30%. However, further improvement on the mechanical performance and the enhancement of the hydrolytic stability of those materials will be highly necessary for applications in the biomedical fieldPortuguese Foundation for Science and Tecnology (FCT), Ministry of Science and Tehnology, Portuga
Transforming growth factor-beta3-loaded microtextured membranes for skin regeneration in dermal wounds.

Contains fulltext :
                  59208.pdf (publisher's version ) (Open Access)Adverse effects of wound healing, such as excessive scar tissue formation, wound contraction, or nonhealing wounds represent a major clinical issue in today's healthcare. Transforming growth factor (TGF)-beta3 has specifically been implicated in wound healing. Our hypothesis was that local administration of TGF-beta3 to excisional dermal wounds would diminish wound contraction and scar formation. Microtextured wound covers, containing different concentrations of TGF-beta3, were placed onto full-thickness excisional skin wounds in guinea pigs. Tattooed reference marks were used to quantify wound contraction. Sixty-four male guinea pigs in four study groups (5 ng TGF-beta3, 50 ng TGF-beta3, no growth factor, sham wound) were followed for up to 6 weeks. We analyzed 19 different parameters of wound healing. Results showed that, in some instances, the 50-ng TGF-beta3 group gave less contraction, whereas the 5-ng TGF-beta3 group gave more contraction. These differences confirm that TGF-beta3 has an optimum working concentration, and suggest this concentration to be closer to 50 ng than to 5 ng TGF-beta3. However, only very few significant differences occurred, and thus we conclude that the clinical relevance of our findings is negligible. Earlier studies, reporting clinically improved wound healing by TGF-beta3, could therefore not be confirmed by this study
Synthesis and evaluation of novel bioactive composite starch/bioactive glass microparticles

The aim of the development of composite materials is to combine the most desired properties of two or more materials. In this work, the biodegradable character, good controlled-release properties, and natural origin of starch-based biomaterials are combined with the bioactive and bone-bonding properties of bioactive glass (BG). Novel, bioactive composite starch-BG microparticles were synthesized starting from a blend of starch and polylactic acid (50%/50% wt) with BG 45S5 powder using a simple emulsion method. Morphological and chemical characterization showed that these particles exhibited a spherical morphology with sizes up to 350 m and that BG 45S5 was incorporated successfully into the composite particles. Upon immersion in a solution simulating body fluids, for periods up to 3 weeks, their bioactive nature was confirmed, as a calcium-phosphate layer resembling biological apatite was formed onto their surface. The short-term cytotoxicity of these materials was also tested by placing 24-h leachables of the materials extracted in culture medium in contact with a fibroblastic cell line (L929) up to 72 h. At this time period, two biochemical tests - MTT and total protein quantification - were performed. The results showed that these materials are not cytotoxic. These results constitute the basis of future encapsulation studies using bone-acting therapeutic agents such as bone morphogenetic proteins or other bone-relevant factors. The particles developed here may be very useful for applications in which controlled release, degradability, and bone-bonding ability are the main requirements.FCT Foundation for Science and Technology, through funds from the POCTI and/or FEDER programmes
Cytokine secretion from mononuclear cells cultured in vitro with starch-based polymers and poly-L-lactide

The cytokine network is one of the major controlling systems of the inflammatory process, driving the magnitude and duration of the host response against invading microorganisms, foreign materials, or altered internal stimuli. Pro- and antiinflammatory cytokines were quantified after in vitro culture of a mixed population of monocytes/macrophages and lymphocytes with biodegradable polymers. Different blends of starch-based polymers and their composites filled with hydroxyapatite were studied and compared with poly-L-lactide. Interleukin (IL)-1, IL-6, and tumour necrosis factor- were investigated as the markers of immunological reactivity because they are known to act at the early stages of injury/invasion. Interferon-, recognized as a proinflammatory cytokine, although not present during early responses was also investigated. Contrarily, IL-4 derived from T lymphocytes, was investigated because it is an immunoregulator that counteracts some aspects of inflammation. T lymphocyte activation was also determined by quantifying IL-2. The results support the hypothesis that different biodegradable polymers can affect mononuclear cell activation and the production of several cytokines associated with the inflammatory process. No IL-2 or interferon- was found in the culture supernatants after 3, 7, and 14 days in the presence of any of the materials. IL-6 was detected in the highest amounts, for all the conditions, followed by tumour necrosis factor-. IL-1 was produced in very low amounts, being undetectable with some of the starch-based materials. IL-4 was the only cytokine that did not demonstrate any significant difference within this group of materials. Starch-based polymers and composites induced lower production of proinflammatory cytokines in comparison to poly-L-lactide.Fundação para a Ciência e a Tecnologia (FCT
Entrapment ability and release profile of corticosteroids from starch-based microparticles

We previously described the synthesis of starchbased microparticles that were shown to be bioactive (when combined with Bioactive Glass 45S5) and noncytotoxic. To
further assess their potential for biomedical applications such as controlled release, three corticosteroids with a similar basic structure—dexamethasone (DEX), 16-methylprednisonole
(MP), and 16-methylprednisolone acetate
(MPA) - were used as models for the entrapment and release of bioactive agents. DEX, MP, and MPA were entrapped
into starch-based microparticles at 10% wt/wt of the starch-based polymer and the loading efficiencies, as well as the release profiles, were evaluated. Differences were
found for the loading efficiencies of the three corticosteroids, with DEX and MPA being the most successfully loaded (82 and 84%, respectively), followed by MP (51%). These differences might be explained based on the differential distribution of the molecules within the matrix of the microparticles.
Furthermore, a differential burst release was observed in the first 24 h for all corticosteroids with DEX and MP being
more pronounced (around 25%), whereas only 12% of MPA was released during the same time period. Whereas the water uptake profile can account for this first stage burst
release, the subsequent slower release stage was mainly attributed to degradation of the microparticle network. Differences
in the release profiles can be explained based on the structure of the molecule, because MPA, a more bulky and hydrophobic molecule, is released at a slower rate compared
with DEX and MP. In this work, it is shown that these carriers were able to sustain a controlled release of the entrapped corticosteroids over 30 days, which confirms the potential of these systems to be used as carriers for the delivery of bioactive agents
Transparent micro and nano patterned poly(lactic acid) for biomedical applications

The formation of structures in poly(lactic acid) has been investigated with respect to producing areas of regular, superficial features with dimensions comparable to those of cells or biological macromolecules. Nanoembossing, a novel method of pattern replication in polymers, has been used for the production of features ranging from tens of micrometers, covering areas up to 1 cm2, down to hundreds of nanometers. Both micro- and nanostructures are faithfully replicated. Contact-angle measurements suggest that positive microstructuring of the polymer (where features protrude from the polymer surface) produces a more hydrophilic surface than negative microstructuring. The ability to structure the surface of the poly(lactic acid), allied to the polymer’s postprocessing transparency and proven biocompatibility, means that thin films produced in this way will be useful for bioengineers studying the interaction of microand nanodimensioned features with biological specimen, with regard to tissue engineering, for example.Postprint (published version
Calcium carbonate-calcium phosphate mixed cement compositions for bone reconstruction

The feasibility of making calcium carbonate-calcium phosphate (CaCO3-CaP) mixed cements, comprising at least 40 % (w/w) CaCO3 in the dry powder ingredients, has been demonstrated. Several original cement compositions were obtained by mixing metastable crystalline calcium carbonate phases with metastable amorphous or crystalline calcium phosphate powders in aqueous medium. The cements set within at most 1 hour at 37°C in atmosphere saturated with water. The hardened cement is microporous and exhibits weak compressive strength. The setting reaction appeared to be essentially related to the formation of a highly carbonated nanocrystalline apatite phase by reaction of the mestastable CaP phase with part or almost all of the metastable CaCO3 phase. The recrystallization of metastable CaP varieties led to a final cement consisting of a highly carbonated poorly crystalline apatite (PCA) analogous to bone mineral associated with various amounts of vaterite and/or aragonite. The presence of controlled amounts of CaCO3 with a higher solubility than the apatite formed in the well-developed calcium phosphate cements might be of interest to increase resorption rates in biomedical cement and favor its replacement by bone tissue. Cytotoxicity testing revealed excellent cytocompatibility of CaCO3-CaP mixed cement compositions
Biofilm formation by Staphylococcus epidermidis on nitrogen ion implanted CoCrMo alloy material

Staphylococcus epidermidis is the primary cause of medical device-related infections due to its adhesion and biofilm forming abilities on biomaterial surfaces. For this reason development of new materials and surfaces to prevent bacterial adhesion is inevitable. In this study, the adhesion of biofilm forming S. epidermidis strain YT-169a on nitrogen (N) ion implanted as well as on as-polished CoCrMo alloy materials were investigated. A medical grade CoCrMo alloy was ion implanted with 60 keV N ions to a high dose of 1.9 × 10 18 ions/cm2 at substrate temperatures of 200 and 400°C. The near-surface implanted layer crystal structures, implanted layer thicknesses, and roughnesses were characterized by XRD, SEM and AFM. The number of adherent bacteria on the surfaces of N implanted specimens was found to be 191 × 106 CFU/cm2 for the 200°C and 70 × 106 CFU/cm2 for the 400°C specimens compared to the as-polished specimen (3 × 106 CFU/cm2). The adhesion test results showed that S. epidermidis strain YT-169a adhere much more efficiently to the N implanted surfaces than to the as-polished CoCrMo alloy surface. This was attributed mainly to the rougher surfaces associated with the N implanted specimens in comparison with the relatively smooth surface of the as-polished specimen
Controlled release of an antibiotic, gentamicin sulphate,\ud
from gravity spun polycaprolactone fibers

The antibiotic, gentamicin sulphate (GS), was\ud
incorporated in gravity-spun polycaprolactone (PCL)\ud
fibers by spinning from particulate suspensions of the\ud
drug in PCL solution to produce a controlled delivery\ud
system. The production rate of GS-loaded PCL fibers was\ud
confined to the range 1–1.5 m/min and the fiber diameter\ud
to 170–220 lm. The kinetics of drug release could be\ud
adjusted by varying the GS loading of the fibers and the\ud
suspension preparation conditions. Gradual release of\ud
*80% of the initial GS content was measured in phosphate\ud
buffered saline at 378C over 50 days from fibers\ud
spun from nonhomogenized suspensions, whereas loss of\ud
this amount of antibiotic occurred in less than 10 days\ud
from fibers spun from homogenized suspensions. Studies\ud
of growth inhibition of Stapyhlococcus epidermidis in culture\ud
indicated that GS released after 2 weeks from PCL\ud
fibers retained antibacterial activity. This behavior recommends\ud
further investigation of PCL fibers for local delivery\ud
of antibiotics to combat infection associated with\ud
periodontal disease, musculoskeletal injuries, and implantation\ud
of fiber-based tissue substitutes such as vascular\ud
prostheses
A novel, tissue occlusive poly(ethylene glycol) hydrogel material

The use of guided bone regeneration (GBR) techniques requires new materials meeting the needs of clinical application. Design criteria for GBR devices are biocompatibility, tissue occlusion, space provision, and clinical manageability. This study evaluates a novel biodegradable poly (ethylene glycol) (PEG) based material as tissue occlusive membrane. A subcutaneous implant model in rats was developed to test the barrier function of the PEG hydrogels over time. Fourteen rats received three membrane implants and two positive controls each. Explants were collected over a period of 7 months. Histological analysis revealed that for at least 4 months cellular infiltration in the membrane explants was lower than 1% of that of the positive controls. Therefore, the PEG based hydrogel can be regarded as tissue occlusive during this period of time. A barrier function seems to be maintained for up to 6 months. In vitro degradation studies performed with the same PEG constructs confirm the in vivo result. In conclusion, our results indicate that this novel PEG-based material has potential for use as a GBR barrier membrane
Skeletal myogenesis on highly orientated microfibrous polyesterurethane scaffolds

Skeletal myogenesis is a complex process, which is known to be intimately depending on an optimal outside-in substrate-cell signaling. Current attempts to reproduce skeletal muscle tissue in vitro using traditional scaffolds mainly suffer from poor directionality of the myofibers, resulting in an ineffective vectorial power generation. In this study, we aimed at investigating skeletal myogenesis on novel biodegradable microfibrous scaffolds made of DegraPol, a block polyesterurethane previously demonstrated to be suitable for this application. DegraPol was processed by electrospinning in the form of highly orientated ("O") and nonorientated ("N/O") microfibrous meshes and by solvent-casting in the form of nonporous films ("F"). The effect of the fiber orientation at the scaffold surface was evaluated by investigating C2C12 and L6 proliferation (via SEM analysis and alamarBlue test) and differentiation (via RT-PCR analysis and MHC immunostaining). We demonstrated that highly orientated elastomeric microfibrous DegraPol scaffolds enable skeletal myogenesis in vitro by aiding in (a) myoblast adhesion, (b) myotube alignment, and (c) noncoplanar arrangement of cells, by providing the necessary directional cues along with architectural and mechanical support.status: publishe
Novel hydroxyapatite/carboxymethylchitosan composite scaffolds prepared through an innovative ‘‘autocatalytic’’ electroless coprecipitation route

A developmental composite scaffold for bone
tissue engineering applications composed of hydroxyapatite
(HA) and carboxymethylchitosan (CMC) was obtained
using a coprecipitation method, which is based on the
‘‘autocatalytic’’ electroless deposition route. The results
revealed that the pores of the scaffold were regular, interconnected,
and possess a size in the range of 20–500 lm.
Furthermore, the Fourier transform infra-red spectrum of
the composite scaffolds exhibited all the characteristic
peaks of apatite, and the appearance of typical bands from
CMC, thus showing that coprecipitation of both organic
and inorganic phases was effective. The X-ray diffraction
pattern of composite scaffolds demonstrated that calciumphosphates
consisted of crystalline HA. From microcomputed
tomography analysis, it was possible to determine
that composite scaffolds possess a 58.9% 6 6% of porosity.
The 2D morphometric analysis demonstrated that on
average the scaffolds consisted of 24% HA and 76%
CMC. The mechanical properties were assessed using
compressive tests, both in dry and wet states. Additionally,
in vitro tests were carried out to evaluate the wateruptake
capability, weight loss, and bioactive behavior
of the composite scaffolds. The novel hydroxyapatite/
carboxymethylchitosan composite scaffolds showed
promise whenever degradability and bioactivity are simultaneously
desired, as in the case of bone tissue-engineering
scaffolding applications.Contract grant sponsor: European Union (STREP Project HIPPOCRATES); contract grant number: NMP3-CT-2003-50575