Sodium alginate

Alginate (A7003), medium viscosity alginate (A2033), low viscosity alginate (A2158), fucoidan (F5631), laminaran (L9634), gum Arabic (G9752), oat spelt xylan, and polygalacturonic acid (P3889) were obtained from Sigma-Aldrich. A sodium alginate from Laminaria hyperborea stipes was kindly provided by DuPont (Landerneau, France). High viscosity alginate (02154723, MP Biochemicals) and very low viscosity alginate (A18565, Alfa Aesar) were kindly provided by Dr Richard Blackburn (University of Leeds). Tamarind xyloglucan, potato galactan, guar galactomannan, sugar beet arabinan and citrus pectin were obtained from Megazyme International (Bray, Ireland).
The MM- and GG-blocks of alginates were prepared using the DuPont sodium alginate according to Heyraud et al. (1996) (link). A 0.5% alginate solution was hydrolyzed for 5 h at 100 °C in 0.3 M HCl. After selective precipitation and centrifugation, the blocks were dialyzed, freeze-dried, and re-suspended in distilled water, and respective M/G compositions monitored by NMR. The MM- and GG-blocks were further fragmented using alginate M-lyase (Lundqvist et al., 2012 (link)) and alginate G-lyase (Thomas et al., 2013 (link)), respectively. The enzymatic degradation and the purification of the released oligosaccharides was performed as described previously (Thomas et al., 2013 (link)).

Sodium alginate (viscosity: 100–300
mPa’s, DuPont, Wilmington, DE, USA) was first dissolved in
DI water (1.5% w/v) at ambient temperature by magnetic stirring until
a clear solution was obtained. Next, a calcium chloride solution (0.1%,
w/v) containing designated amounts of the IPNEs and CCNPs was added
to the above alginate solution under 800 rpm agitation. The mixture
was continuously stirred at 800 rpm under ambient temperature for
20 min, after which the I_PEC_CNAHG was obtained.
The I_PEC_CNAHG was stored in the dark at 4 °C
until use. The structure, configuration, and nanovector distribution
of I_PEC_CNAHG were detected by SEM. The fabrication
of I_PEC_CNAHG including the preparation of IPNEs
and CCNPs is schematically presented in Figure 1A.

Calcium nitrate tetrahydrate (Fisher, Hampton, NH, USA), ammonium phosphate (Fisher, USA), ammonium hydroxide (Sigma Aldrich, Oakville, ON, USA), hydroxyapatite (Sigma Aldrich, Oakville, ON, Canada), atelo-collagen solution (Advanced BioMatrix, Carlsbad, CA, USA), sodium hydroxide (Fisher, USA), and sodium alginate (DuPont, Wilmington, DE, USA) were utilized for ink preparation. Calcium chloride (Fisher, Schwerte, Germany) and glutaraldehyde (Sigma-Aldrich, Schnelldorf, Germany) were used as crosslinking agents. Thymol (Fisher, USA), ethanol (Fisher, USA), and citric acid (Sigma Aldrich, USA) for dentin disk preparation and polystyrene microspheres (Sigma Aldrich, USA) for the occlusion test were utilized. For cell study, bone marrow-derived stem cells (Lonza, Bend, OR, USA), high glucose DMEM (Gibco, Thermo Fisher, Ottawa, ON, Canada), fetal bovine serum (Gibco, Canada), 1% penicillin–streptomycin (Gibco, Canada), ascorbic acid (Sigma Aldrich, Oakville, ON), dexamethasone (Thermo Fisher, Waltham, MA, USA), and β-glycerophosphate (Sigma Aldrich, Oakville, ON, Canada) were used.