Fig. 4: HA-BP•Laponite gels are compromised by edge-site or bisphosphonate-associating ions. | Nature Communications

Fig. 4: HA-BP•Laponite gels are compromised by edge-site or bisphosphonate-associating ions.

From: Bisphosphonate nanoclay edge-site interactions facilitate hydrogel self-assembly and sustained growth factor localization

Fig. 4

Compared with gels prepared in the absence of pyrophosphate (a), screening of Laponite edge sites with pyrophosphate ions (PPi) prior to mixing with HA-(BP)3 reduced the stiffness of the gels by half. Stiffness partially recovered post swelling suggesting release of PPi and the formation of new physical cross-links (b). Preincubation of HA-(BP)3 with BP-competing Mg2+ ions caused an initial increase in gel stiffness consistent with Mg2+ cation bridging of Laponite particles. Osmotic release of interlayer Mg2+ revealed that swelling-resistant BP•Laponite cross-links (a) were compromised by addition of Mg2+ (c). Storage modulus (G′) is recorded at 1 Hz.

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