Physicochemical model of alginate–poly-l-lysine microcapsules defined at the micrometric/nanometric scale using ATR-FTIR, XPS, and ToF-SIMS

Tam, Susan K.; Dusseault, Julie; Polizu, Stéfania; Ménard, Martin; Hallé, Jean‐Pierre; Yahia, L’Hocine

doi:10.1016/j.biomaterials.2005.05.007

Cited by 182 publications

(121 citation statements)

References 41 publications

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“…Since we previously did not find any activation of the classical or lectin pathway by poly-L-lysine microcapsules, but elevated levels of the activation product Bb from the alternative pathway [14], we suggest that the C3 convertase activity is due to a direct binding through C3 tick-over activation to the poly amine groups of the alginate microcapsules. The analysis of the membrane of alginatePLL microcapsules has shown that PLL is exposed in the outermost surface of microcapsules [18,21] either as a complex with alginate or as a random coil exposing free amino groups [21]. Our data demonstrate a trend of increased complement reactivity with increased concentration of PLL for the solid core PLL-containing microcapsules using high G alginate, which probably reflected an increased amount of free amino groups to react with C3.…”

Section: Cd11b Cd18 or Cd11c Blockagementioning

confidence: 57%

Alginate microsphere compositions dictate different mechanisms of complement activation with consequences for cytokine release and leukocyte activation

Ørning

Hoem

Coron

et al. 2016

Journal of Controlled Release

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The inflammatory potential of 12 types of alginate-based microspheres was assessed in a human whole blood model. The inflammatory potential could be categorized from low to high based on the four main alginate microsphere types; alginate microbeads, liquefied core poly-L-ornithine (PLO)-containing microcapsules, liquefied core poly-L-lysine (PLL)-containing microcapsules, and solid core PLLcontaining microcapsules. No complement or inflammatory cytokine activation was detected for the Ca/Ba alginate microbeads. Liquefied core PLO-and PLL-containing microcapsules induced significant fluid phase complement activation (TCC), but with low complement surface deposition (anti-C3c), and a low proinflammatory cytokine secretion, with exception of an elevated MCP-1(CCL2) secretion. The solid core PLL-containing microcapsules generated lower TCC but a marked complement surface deposition and significant induction of the proinflammatory cytokines interleukin (IL-1)β, TNF, IL-6, the chemokines IL-8 (CXCL8), and MIP-1α (CCL3) and MCP-1(CCL2).Inhibition with compstatin (C3 inhibitor) completely abolished complement surface deposition, leukocyte adhesion and the proinflammatory cytokines. The C5 inhibitions partly lead to a reduction of the proinflammatory cytokines. The leukocyte adhesion was abolished by inhibitory antibodies against CD18 and partly reduced by CD11b, but not by CD11c. Anti-CD18 significantly reduced the (IL-1)β, TNF, IL-6 and MIP-1α and anti-CD11b significantly reduced the IL-6 and VEGF secretion. MCP-1 was strongly activated by anti-CD18 and anti-CD11b. In conclusion the initial proinflammatory cytokine responses are driven by the microspheres potential to trigger complement C3 (C3b/iC3b) deposition, leukocyte activation and binding through complement receptor CR3 (CD11b/CD18).MCP-1 is one exception dependent on the fluid phase complement activation mediated through CR3.

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Section: Cd11b Cd18 or Cd11c Blockagementioning

confidence: 57%

Alginate microsphere compositions dictate different mechanisms of complement activation with consequences for cytokine release and leukocyte activation

Ørning

Hoem

Coron

et al. 2016

Journal of Controlled Release

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“…The XPS study shows detectable content of nitrogen arising from PLL-modified graphene films compared to a native graphene films. The N1s atomic concentrations of the graphene surfaces for pre-and post-PLL modification are 0.68% and 2.78%, proving the success of PLL modification, which was further validated by presence of the N 1s peaks (HNeC]O, CeNH 2 , CeNH 3 þ ) [27].…”

Section: Surface Characterization Of Substratementioning

confidence: 82%

The promotion of neurite sprouting and outgrowth of mouse hippocampal cells in culture by graphene substrates

et al. 2011

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a b s t r a c tGraphene has been demonstrated in many biomedical applications and its potentials for neural interfacing. Emerging concerns on graphene, as a biomedical material, are its biocompatibility and how biologically targeted tissue/cells respond to it. Relatively few studies attempted to address the interactions of graphene or its derivatives with the tissues/cells, while very few reports on neural system. In this study, we tried to explore how neurites, one of the key structures for neural functions, are affected by graphene during the development until maturation in a mouse hippocampal culture model. The results reveal that graphene substrates exhibited excellent biocompatibility, as cell viability and morphology were not affected. Meanwhile, neurite numbers and average neurite length on graphene were significantly enhanced during 2e7 days after cell seeding compared with tissue culture polystyrene (TCPS) substrates. Especially on Day 2 of the neural development period, graphene substrates efficiently promoted neurite sprouting and outgrowth to the maximal extent. Additionally, expression of growthassociate protein-43 (GAP-43) was examined in both graphene and TCPS groups. Western blot analysis showed that GAP-43 expression was greatly enhanced in graphene group compared to TCPS group, which might result in the boost of neurite sprouting and outgrowth. This study suggests the potential of graphene as a material for neural interfacing and provides insight into the future biomedical applications of graphene.

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“…For this reason, another external alginate coating is often added to the beads to form the so-called 'alginate-polylysine -alginate' (APA) system. However, developments in the characterization of APA capsules [92] suggest that these capsules are not multi-layered; instead they consist of an inner calciumalginate core covered by one single external layer of a poly-L-lysine and alginate blend. The binding strength of the initial poly-L-lysine layer depends on the relative ratio of the G and M blocks in the alginate core.…”

Section: Alginatementioning

confidence: 99%

Natural polymers for the microencapsulation of cells

Gasperini

Mano

Reis

2014

J. R. Soc. Interface.

531

413

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The encapsulation of living mammalian cells within a semi-permeable hydrogel matrix is an attractive procedure for many biomedical and biotechnological applications, such as xenotransplantation, maintenance of stem cell phenotype and bioprinting of three-dimensional scaffolds for tissue engineering and regenerative medicine. In this review, we focus on naturally derived polymers that can form hydrogels under mild conditions and that are thus capable of entrapping cells within controlled volumes. Our emphasis will be on polysaccharides and proteins, including agarose, alginate, carrageenan, chitosan, gellan gum, hyaluronic acid, collagen, elastin, gelatin, fibrin and silk fibroin. We also discuss the technologies commonly employed to encapsulate cells in these hydrogels, with particular attention on microencapsulation.

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Physicochemical model of alginate–poly-l-lysine microcapsules defined at the micrometric/nanometric scale using ATR-FTIR, XPS, and ToF-SIMS

Cited by 182 publications

References 41 publications

Alginate microsphere compositions dictate different mechanisms of complement activation with consequences for cytokine release and leukocyte activation

Alginate microsphere compositions dictate different mechanisms of complement activation with consequences for cytokine release and leukocyte activation

The promotion of neurite sprouting and outgrowth of mouse hippocampal cells in culture by graphene substrates

Natural polymers for the microencapsulation of cells

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