Revisiting the Synthesis and Characterization of Hybrid Nanomaterial Constituted by Folate Intercalated into M²⁺/Al³⁺ (M²⁺ = Mg²⁺ and Zn²⁺) Layered Double Hydroxide

Intercalation of deprotonated folic acid (FA; vitamin B9) is of great interest for nutraceutical and cosmeceutical purposes. Although some studies have already reported the intercalation of divalent (HFol²⁻) or trivalent (Fol³⁻) folate anions into layered double hydroxides (LDH), the structure, spectroscopic, and thermal behavior of such hybrid materials still need to be better understood. This work revisited the synthesis of LDH constituted by M²⁺/Al³⁺ (M²⁺ = Mg or Zn) intercalated with HFol²⁻ or Fol³⁻. Insights concerning how the physicochemical properties of the materials are tuneable according to the synthetic approach (slow or fast coprecipitation) and pH value (7.5 or 9.0/9.5) of synthesis were pointed out. Materials synthesized at pH above 9.0 (Fol³⁻) presented larger particles and lower loading capacity than the ones synthesized at pH 7.5 (HFol²⁻). The fast coprecipitation approach led to the formation of materials with smaller particles. This work could address the following research concerning LDH-FA applications.

Keywords:
layered double hydroxide (LDH); folic acid; vitamin B9; hybrid materials; intercalation compounds