Amount of human albumin secreted by HepG2 cells in the supernatant of the mineralised beads.

<p>Concentrations showed the daily albumin released outside of the hybrid alginate-silica material as means ± 1 S.D. (n = 3).</p

Concentration-dependent effects of different sol-gel by-products on HepG2 cells after 5 hours of incubation.

<p>The membrane damaging effect of chemicals was quantified by measuring the release of the cytosolic enzyme LDH. Results are presented in percentage of cytotoxicity as means ± 1 S.D. (n = 3).</p

In vitro determination of a proinflammatory response due to alginate or silica around cells.

<p>Proinflammatory response is highlighted by IL-8, which is secreted by monocytes THP-1 (immune defenders) when they are activated. The control (a) are made without THP-1 to underline the basal concentration of IL-8 produced by HepG2 cells. Results are presented as means ± 1 S.D. (n = 3).</p

Steps for microencapsulation of animal cells into hybrid alginate-silica beads.

<p>Cells in suspension are pre-encapsulated in Ca-alginate capsules and transferred in a diluted sodium silicate solution. The beads are finally coated with a Ca-alginate layer.</p

Microscopy images highlighting the survival of cells 6 weeks after immobilisation.

<p>Brightfield (a, c) and fluorescent microscopy images (b, d) of HepG2 cells three-dimensionally entrapped within a mineralised bead and labelled with fluorescein diacetate (viability probe). The micrographs were taken 1 day (a, b) and 42 days (c, d) post-encapsulation.</p

Conditions tested to perform the <i>in vitro</i> immune response test. Determination of IL-8 released in the supernatant, synonym of a proinflammatory response.

<p>Conditions tested to perform the <i>in vitro</i> immune response test. Determination of IL-8 released in the supernatant, synonym of a proinflammatory response.</p

SEM micrographs (a, b, c) and EDX spectrum (d) of a cross section of a mineralised bead.

<p>The bead was conserved in vitro in the biological medium during one month.</p

Microscopy images of an alginate capsule and a mineralized bead showing the silification.

<p>Brightfield (a, c, e) and fluorescent microscopy images (b, d, f) of an alginate capsule (a–b) and a mineralised bead (c–f) in the presence of PDMPO (silica tracer). Micrographs (a–d) and (e–f) correspond to representative cross sections of the materials and to a whole bead, respectively.</p

Nitrogen adsorption-desorption isotherms.

<p>Isotherms obtained by analysis of purified alginate capsules (a) and mineralised beads (b).</p

Comparison of oxygen consumption at HepG2 cells encapsulated within (a) alginate capsule or (b) mineralised bead.

<p>100% corresponds to the oxygen consumption of cells entrapped within one bead (1.8 10² µmole of O₂ hour⁻¹ bead⁻¹). Results are presented as means ± 1 S.D. (n = 3).</p