pinecone/core-2020-05-10-deduplication huggingface dataset:
An in vivo study of the host response to starch-based polymers and composites subcutaneously implanted in rats

Implant failure is one of the major concerns in the biomaterials field. Several factors have been related to the fail but in general these biomaterials do not exhibit comparable
physical, chemical or biological properties to natural tissues and ultimately, these devices can lead to chronic inflammation and foreign-body reactions. Starch-based biodegradable
materials and composites have shown promising properties for a wide range of biomedical applications as well as a reduced capacity to elicit a strong reaction from immune system cells in vitro. In this work, blends of corn starch with ethylene vinyl alcohol (SEVA-C), cellulose acetate (SCA)
and polycaprolactone (SPCL), as well as hydroxyapatite (HA) reinforced starch-based composites, were investigated in vivo. The aim of the work was to assess the host response evoked for starch-based biomaterials, identifying the presence
of key cell types. The tissues surrounding the implant were harvested together with the material and processed histologically for evaluation using immunohistochemistry.
At implant retrieval there was no cellular exudate around the implants and no macroscopic signs of an inflammatory reaction
in any of the animals. The histological analysis of the sectioned interface tissue after immunohistochemical staining using ED1, ED2, CD54, MHC class II and a/b antibodies
showed positively stained cells for all antibodies, except for a/b for all the implantation periods, where it was different for the various polymers and for the period of implantation.
SPCL and SCA composites were the materials that stimulated the greatest cellular tissue responses, but generally biodegradable
starch-based materials did not induce a severe reaction for the studied implantation times, which contrasts with other types of degradable polymeric biomaterials.Fundação para a Ciência e a Tecnologia (FCT
Drug release of pH/temperature-responsive calcium alginate/poly(N-isopropylacrylamide) semi IPN beads

A series of semi-interpenetrating, polymer
network (semi-IPN), hydrogel beads, composed of calcium
alginate (Ca-alginate) and poly(N-isopropylacrylamide)
(PNIPAAM), were prepared for a pH/temperature-sensitive
drug delivery study. The equilibrium swelling showed the
independent pH- and thermo- responsive nature of the
developed materials. At pH¼2.1, the release amount of
indomethacin incorporated into these beads was about 10%
within 400 min, while this value approached to 95% at
pH¼7.4. The release rate of the drug was higher at 37 8Cthan
that at 25 8C and increased slightly with increasing
PNIPAAM content. These results suggest that the Caalginate/
PNIPAAM beads have the potential to be used as
an effective pH/temperature sustainable delivery system of
bioactive agents
Surface structural investigation of starch-based biomaterials

Surface structural characterisation of three different starch-based blends (with poly[ethyleneco-(
vinyl alcohol)], cellulose acetate and polycaprolactone) was carried out. The results show
that there is a difference between the bulk and the surface composition of all studied blends.
Two different hypotheses were investigated –
predominant presence of a synthetic component
on the surface and possible inter- and/or intramolecular
bonds. The results were related to
previous data for cell behaviour on those
materials. It was found that both surface hydrophilicity
and surface functionality are of great
importance for cell adhesion and growth on
starch-based biomaterials
Plasma surface modification of chitosan membranes: characterization and preliminary cell response studies

Surface modification of biomaterials is a way to tailor cell responses whilst retaining the bulk
properties. In this work, chitosan membranes were prepared by solvent casting and treated
with nitrogen or argon plasma at 20Wfor 10–40 min. AFM indicated an increase in the surface
roughness as a result of the ongoing etching process. XPS and contact angle measurements
showed different surface elemental compositions
and higher surface free energy. The
MTS test and direct contact assays with an
L929 fibroblast cell line indicated that the
plasma treatment improved the cell adhesion
and proliferation. Overall, the results demonstrated
that such plasma treatments could
significantly improve the biocompatibility of
chitosan membranes and thus improve their
potential in wound dressings and tissue
engineering applications
Genipin modified silk fibroin nanometric-nets

Nanometric silk-fibroin nets were fabricated by electrospinning from regenerated Bombyx mori silk-fibroin (SF)/formic acid solutions with the addition of genipin (GE), 2, 15 and 24 h after the solution preparation. After spinning, the pure fibroin nanofibers were water soluble and needed a further stabilization process, whereas the reaction of fibroin with genipin resulted in water-insoluble fibroin nets due to conformational changes induced in the fibroin by the genipin. SFGE nanofibers presented diameters ranging from 140 to 590 nm and were generally thinner than pure SF nanofibers. The secondary structure of SF into SFGE nanofibers showed the presence of a β-sheet conformation together with β-turn intermediates (turns and bends). The approach described in this paper provides an alternative method of designing SF nanofibers that are already water insoluble, without any stability post-treatment needed
Poly(amidoamine) Conjugates Containing Doxorubicin Bound via an Acid-Sensitive Linker.

Poly(amidoamine)s with amino pendant groups were prepared by hydrogen-transfer polyaddition of primary and secondary amines to bis-acrylamines. Dansyl cadaverine (DC) doxorubicin (Dox) were bound to the polymers via a cis-aconityl spacer to give conjugates containing 3 µg of DC per mg of polymer and 28 to 35 µg of Dox per mg of polymer. Release of DC and Dox at physiological and acidic pH varied from 0 to 35% over 48 h and was pH dependent. Although the ISA1Dox conjugate (IC50 = 6 µg Dox · mL-1) presented similar toxicity as the parent polymer without Dox, ISA23Dox showed increased toxicity (IC50 = 10 µg Dox · mL-1). These results suggest that ISA23Dox is able to release biologically active Dox in vitro and that this conjugate might be suitable for further development
Vascularization in bone tissue engineering : physiology, current strategies, major hurdles and future challenges

The lack of a functional vascular supply has, to a large extent, hampered the whole range of
clinical applications of ‘successful’ laboratory-based bone tissue engineering strategies. To the
present, grafts have been dependent on post-implant vascularization, which jeopardizes graft
integration and often leads to its failure. For
this reason, the development of strategies that
could effectively induce the establishment of a
microcirculation in the engineered constructs
has become a major goal for the tissue engineering
research community. This review
addresses the role and importance of the development
of a vascular network in bone tissue
engineering and provides an overview of the
most up to date research efforts to develop such
a network.M. I. Santos would like to acknowledge the Portuguese Foundation for Science and Technology (FCT) for her Ph.D. grant (SFRH/BD/13428/2003). This work was partially supported by FCT through funds from POCTI and/or FEDER programs and by the European Union funded STREP Project HIPPOCRATES (NMP3-CT-2003-505758). This work was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283). The authors also acknowledge Gabriela A. Silva for critically reading the manuscript
Carboxymethylchitosan/poly (amidoamine) dendrimer nanoparticles in central nervous systems-regenerative medicine: effects on neuron/glial cell viability and internalization efficiency

The applicability of CMCht/PAMAM dendrimer nanoparticles for CNS applications was
investigated. AFM and TEM observations revealed that the nanoparticles possessed a nanosphere-
like shape with a size from 22.0 to 30.7 nm. The nanoparticles could be bound to
fluorescent-probe FITC for tracing purposes. Post-natal hippocampal neurons and cortical glial
cells were both able to internalize the FITC-labeled
CMCht/PAMAM dendrimer nanoparticles with
high efficiency. The percentage of positive cells
internalizing the nanoparticles varied, reaching a
peak after 48 h of incubation. Further experiments
for periods up to 7 d revealed that the
periodical addition of FITC-labelled CMCht/
PAMAM dendrimer nanoparticles was needed to
maintain the overall percentage of cells internalizing
them. Finally, it was also observed that cell
viability was not significantly affected by the
incubation of dendrimer nanoparticles.Financial support from the Portuguese Foundation for Science and Technology through funds from POCTI and/or FEDER programs (Funding to ICVS, 3B's Research Group, post-doctoral and pre-doctoral fellowships to A.J. Salgado and J.M. Oliveira - SFRH/BPD/17595/2004; SFRH/BD/21786/2005) is gratefully acknowledged. This work was also carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283) and HIPPOCRATES STREP (NMP3-CT-2003-505758) projects
The influence of patterned nanofiber meshes on human mesenchymal stem cell osteogenesis

A specially designed electroconductive collector enables the electrospinning of P-NFM composed of areas of parallel/uniaxially aligned fibers and areas of random/orthogonal nanofiber distribution. The biological relevance of P-NFM is demonstrated using hBMSCs as an autologous cell source. The structures induce cell orientation along the uniaxially aligned fibers, mainly during earlier culturing periods under basal and osteogenic differentiation conditions. The microtopography of the P-NFM also controls the deposition of mineralized extracellular matrix along the pre-defined fiber direction. Genotypic characterization confirms the successful differentiation into the osteogenic lineage.European Integrated Project GENOSTEM (LSH-STREP-CT-2003-503161); European Network of Excellence EXPERTISSUES (NMP3-CT-2004-500283); Portuguese Foundation for Science and Technology for the project Naturally Nano (POCI/EME/58982/2004) and the PhD grant SFRH/BD/24382/2005
Multifunctionalized CMCht/PAMAM dendrimer nanoparticles modulate the cellular uptake by astrocytes and oligodendrocytes in primary cultures of glial cells

The efficiency of the treatments involving CNS disorders is commonly diminished by the toxicity, reduced stability and lack of targeting of the administered neuroactive compounds. In this study, we have successfully multifunctionalized CMCht/PAMAM dendrimer nanoparticles by coupling the CD11b antibody and loading MP into the nanoparticles. The modification of the new antibody-conjugated nanoparticles was confirmed by S-TEM observation and 1H NMR and FTIR spectroscopy. Cytotoxicity assays revealed that the conjugates did not affect the viability of both primary cultures of glial and microglial cells. Trace analyses of FITC-labelled nanoparticles revealed that the uptake of antibody-conjugated nanoparticles was conserved in microglial cells but significantly decreased in astrocytes and oligodendrocytes. Thus, this study demonstrates that antibody conjugation contributes to a modulation of the internalization of these nanocarriers by different cell types, which might be of relevance for specific targeting of CNS cell populations.The authors would like to acknowledge the Portuguese Foundation for Science and Technology (Pre-Doctoral fellowship to Susana R. Cerqueira SFRH/BD/48406/2008; Post-Doctoral fellowship to Joaquim M. Oliveira SFRH/BPD/63175/2009; Grant No. PTDC/SAU-BMA/114059/2009; Science 2007 Program - Antonio J. Salgado); the Foundation Calouste de Gulbenkian to funds attributed to Antonio J. Salgado under the scope of the The Gulbenkian Programme to Support Research in the Life Sciences; this work was also partially supported by the European FP7 Project Find and Bind (NMP4-SL-2009-229292)
Encapsulation and survival of a chondrocyte cell line within xanthan gum derivative

A chemical derivative of xanthan gum polysaccharide is investigated as a new artificial
matrix for the encapsulation of chondrocytic cells. Toward this goal, a novel micro-droplet
generator is developed to produce microcapsules. Microcapsules with an average diameter
of 500 mm, smooth surface, and homogeneous
size distribution are obtained.
ATDC5 cells encapsulated in carboxymethyl
xanthan (CMX) microcapsules
remain viable and are observed to proliferate
for prolonged culture periods
with enhanced metabolic activity.
Furthermore, retention of the chondrogenic
phenotype is exhibited by the
cells within CMX, suggesting the
ability of this material to be applied
in cell-delivery therapies.This work was supported through the European Union funded project "Find and Bind" (NMP4-SL-2009-229292) under FP7. A. C. M. thanks the Portuguese Foundation for Science Technology for a PhD grant (SFRH/BD/42161/2007). We thank Prof. Manuel Coimbra and Dr. Claudia Nunes from Aveiro University for their assistance with xanthan molecular weight determination
Controlled cell proliferation on an electrochemically engineered collagen scaffold

Therapies for corneal disease and injury often rely on artificial implants, but integrating cells into synthetic corneal materials remains a significant challenge. The electrochemically formed collagen-based matrix presented here is non-toxic to cells and controls the proliferation in the corneal fibroblasts seeded onto it. Histology and biomolecular studies show a behavior similar to corneal stromal cells in a native corneal environment. Not only is this result an important first step toward developing a more realistic, multi-component artificial cornea, but it also opens possibilities for using this matrix to control and contain the growth of cells in engineered tissues
Redox-responsive degradable PEG cryogels as potential cell scaffolds in tissue engineering

A Michael addition strategy involving the reaction between a maleimide double bond and amine groups is investigated for the synthesis of cryogels at subzero temperature. Low-molecular-weight PEG-based building blocks with amine end groups and disulfide-containing building blocks with maleimide end groups are combined to synthesize redox-responsive PEG cryogels. The cryogels exhibit an interconnected macroporous morphology, a high compressive modulus and gelation yields of around 95%. While the cryogels are stable under physiological conditions, complete dissolution of the cryogels into water-soluble products is obtained in the presence of a reducing agent (glutathione) in the medium. Cell seeding experiments and toxicologic analysis demonstrate their potential as scaffolds in tissue engineerin
Functionalized Synthetic Biodegradable Polymer Scaffolds for Tissue Engineering

Scaffolds (artificial ECMs) play a pivotal role in the process of regenerating tissues in 3D. Biodegradable synthetic polymers are the most widely used scaffolding materials. However, synthetic polymers usually lack the biological cues found in the natural extracellular matrix. Significant efforts have been made to synthesize biodegradable polymers with functional groups that are used to couple bioactive agents. Presenting bioactive agents on scaffolding surfaces is the most efficient way to elicit desired cell/material interactions. This paper reviews recent advancements in the development of functionalized biodegradable polymer scaffolds for tissue engineering, emphasizing the syntheses of functional biodegradable polymers, and surface modification of polymeric scaffolds.             Significant efforts have been made to develop functional biodegradable  scaffolds for tissue regeneration that can enhance cell function and guide new tissue formation. This paper discusses the recent advancements of functionalizing synthetic biodegradable polymer scaffolds, focusing on polymer synthesis, surface modification, and cellular response on these functionalized scaffolds
Development of Channeled Nanofibrous Scaffolds for Oriented Tissue Engineering

A tissue‐engineering scaffold resembling the structure of the natural extracellular matrix can often facilitate tissue regeneration. Nerve and tendon are oriented micro‐scale tissue bundles. In this study, a method combining injection molding and thermally induced phase separation techniques is developed to create single‐ and multiple‐channeled nanofibrous poly( L ‐lactic acid) scaffolds. The overall shape, the number and spatial arrangement of channels, the channel wall matrix architecture, the porosity and mechanical properties of the scaffolds are all tunable. The porous NF channel wall matrix provides an excellent microenvironment for protein adsorption and the attachment of PC12 neuronal cells and tendon fibroblast cells, showing potential for neural and tendon tissue regeneration.             A method combining injection molding and thermally induced  phase separation is developed to create single‐ and multiple‐channeled nanofibrous polymer scaffolds. The porous nanofibrous channel wall provides an excellent microenvironment for protein adsorption and cell attachment, showing potential for nerve and tendon regeneration
Poly(ethylene imine)s as Antimicrobial Agents with Selective Activity

We report the structure–activity relationship in the antimicrobial activity of linear and branched poly(ethylene imine)s (L‐ and B‐PEIs) with a range of molecular weights (MWs) (500–12 000). Both L‐ and B‐PEIs displayed enhanced activity against  Staphylococcus aureus  over  Escherichia coli . Both B‐ and L‐PEIs did not cause any significant permeabilization of  E. coli  cytoplasmic membrane. L‐PEIs induced depolarization of  S. aureus  membrane although B‐PEIs did not. The low MW B‐PEIs caused little or no hemolysis while L‐PEIs are hemolytic. The low MW B‐PEIs are less cytotoxic to human HEp‐2 cells than other PEIs. However, they induced significant cell viability reduction after 24 h incubation. The results presented here highlight the interplay between polymer size and structure on activity.             Unmodified poly(ethylene imine)s are shown to act as  selective antibacterial agents. The mechanism of action is likely related to, but not exclusive to, interaction with cell walls and cell membrane damage. These molecules provide a cost effective and chemically facile framework for the further development of selective antimicrobial materials
Unraveling the uptake mechanisms of mannan nanogel in bone-marrow-derived macrophages

The mechanisms associated with the cellular internalization of nanomedicines must be carefully considered when designing drug- and vaccine-delivery systems. The cellular fate and effects of nanomedicines depend to a large extent on the cell uptake routes. A self-assembled mannan nanogel is developed as a vaccination platform for antigen and adjuvant delivery. The mannan nanogel uptake by murine bone-marrow-derived macrophages is found to be time-, concentration-, and energy-dependent, involving mannose-receptor-mediated phagocytosis and clathrin-mediated endocytosis. The nanogel is also visualized in the cytosol suggesting endolysosomal escape. These results indicate that mannan nanogel is a promising versatile carrier for intracellular delivery of vaccines or therapeutic agents.S. A. F. is the recipient of a fellowship from International Iberian Nanotechnology Laboratory (INL). The authors wish to acknowledge the financial support from the Fundacao para a Ciencia e a Tecnologia (FCT, Portugal), trough PTDC. M. V., P.o M. and A. C. were supported by SUDOE-FEDER (IMMUNONET, SOE1/P1/E014). The technical support on confocal studies by Lucilia Goreti Ribeiro Pinto from Life and Health Sciences Research Institute (ICVS), School of Health Sciences, Braga, Portugal, is gratefully acknowledged. The authors thankfully acknowledge the important scientific comments, helpful advice and critical review given by Prof. Dr. Arwyn Tomos Jones, Welsh School of Pharmacy, Cardiff University, Cardiff
Glycol chitosan-based nanogel as a potential targetable carrier for siRNA

A self-assembled glycol chitosan nanogel (GC) is synthesized by chemically grafting hydrophobic chains onto a polysaccharide, which is comprehensively characterized. The obtained macromolecular micelle is decorated with folate-conjugated poly(ethylene glycol) (PEG) (GCFA). An average size distribution of 250 and 200 nm is observed, respectively for the GC and GCFA nanogels. Differential cell localization is observed on incubating the materials with HeLa cells. Whereas the GC nanogel is detected on the cell surface, GCFA is localized in the cytoplasm. The cell viability is not compromised by the nanogels. Interestingly, GC nanogel is poorly internalized by bone marrow derived macrophages (BMDMs), and GCFA is not phagocytosed. Given its ability to complex siRNA, the targetable GC nanogel can be a promising vehicle for siRNA delivery.Paula Pereira thanks FCT, the Ph.D. grant ref SFRH/BD/64977/2009
Development and characterization of PHB-HV based 3D scaffolds for a tissue engineering and cell-therapy combinatorial approach for spinal cord Injury regeneration

Spinal cord injury (SCI) leads to devastating neurological deficits. Several tissue engineering (TE)-
based approaches have been investigated for repairing this condition. Poly (3-hydroxybutyrateco-
3-hydroxyvalerate) (PHB-HV) is found to be particularly attractive for TE applications due to
its properties, such as biodegradability, biocompatibility, thermoplasticity and piezoelectricity.
Hence, this report addresses the development and characterization of PHB-HV-based 3D
scaffolds, produced by freeze-drying, aimed to SCI treatment. The obtained scaffolds reveal an
anisotropic morphology with a fully interconnected
network of pores. In vitro studies demonstrate
a lack of cytotoxic effect of PHB-HV
scaffolds. Direct contact assays also reveal their
ability to support the culture of CNS-derived cells
and mesenchymal-like stem cells from different
sources. Finally, histocompatibility studies show
that PHB-HV scaffolds are well tolerated by the
host tissue, and do not negatively impact the left
hindlimb locomotor function recovery. Therefore
results herein presented suggest that PHB-HV
scaffolds may be suitable for SCI treatment.This study was supported by the Portuguese Foundation for Science and Technology (FCT; Grant no PTDC/SAU-BMA/114059/2009; PEst-C/SAU/LA0001/2013-2014 and RNEM-REDE/1506/REM/2005) and Foundation Calouste Gulbenkian, under the scope of the Gulbenkian Program to Support Cutting Edge Research in Life Sciences (A.J.S.). This work was also partially supported by the European FP7 Project Find and Bind (NMP4-SL-2009-229292). The authors would like to thank Miguel Carvalho, Fabio Teixeira, and Filipa Campos for their collaboration in in vivo experiments
Self-assembling linear and star shaped poly (ε-caprolactone)/poly[(meth)acrylic acid] block copolymers as carriers of indomethacin and quercetin

A amphiphilic linear AB, BAB, and star shaped (AB)(3) block copolymers of poly(E-caprolactone) (PCL)/poly(meth)acrylic acid (P(M)AA) are used for the preparation of nanoparticles and drug entrapment, where indomethacin and quercetin are employed as model drugs. Drug loading experiments with the nanoparticles based on PAA block copolymers demonstrate a higher efficiency for the star structure, whereas the PMAA star copolymer presents the lowest entrapment ability. The release properties are studied at room temperature and 37 degrees C in phosphate buffer solutions with pH equal to 5 and 7.4. The kinetic profiles show a strong relation to the copolymer's topology, indicating the lowest release rates from the star based superstructures, while the PMAA particles are less stable than those containing PAA segment(s)