Al no3 3 9h2o

Deoxyribonucleic acid (DNA) from salmon milt (ca. 100–300 bp, purity >90%) was purchased from Fujifilm Wako (Osaka, Japan). RNA from yeast was purchased from Tokyo Chemical Industry Inc. (Tokyo, Japan). Cytidine-5′-monophosphate (purity 98%), adenosine-5′-monophasphate (purity 98%), guanosine-5′-monophasphate (purity 97%), and uridine-5′-monophasphate (purity 98%) were purchased from Combi Blocks Inc. (San Diego, CA, USA). KNO₃, NaCl, CaCl₂·2H₂O, Al(NO₃)₃·9H₂O, Zn(NO₃)₂·6H₂O, Co(NO₃)₂·6H₂O, Pb(NO₃)₂, NiCl₂·6H₂O, Cu(NO₃)₂·3H₂O from Fujifilm Wako (Osaka, Japan), Hg(NO₃)₂·H₂O and AgNO₃ from Sigma-Aldrich (St. Louis, MO, USA), Cd(NO₃)₂·9H₂O from Combi-Blocks (San Diego, CA, USA), and MgCl₂·6H₂O from Kishida Chemicals (Osaka, Japan) were used for metal ion sensing experiments, as received. Unless otherwise mentioned, deionized water of resistivity 18.2 MOhm⋅cm and purified using a Purelab Chorus 1 Life Science apparatus was used in all experiments.

Reagent-grade Mg(NO₃)₂·6H₂O, Al(NO₃)₃·9H₂O, Na₂CO₃, NaOH, HCl, and NaCl (Wako Pure Chemical Industries, Ltd.) were used. Highly and weakly charged Mg/Al LDHs with x = 0.28 and 0.22, respectively, were synthesised by the conventional co-precipitation method using an aqueous solution containing Mg²⁺ and Al³⁺ ions as a precursor solution and NaOH/Na₂CO₃ aqueous solution as a precipitation agent, followed by hydrothermal treatment at 140 °C for 22 h^{24 –26} . After drying at 60 °C in air, the samples were subjected to the Cl-exchange treatment method using an acidic chloride aqueous solution to eliminate carbonate contamination (immersed overnight in aqueous HCl (33.0 mM) and NaCl (4.0 M) solutions at room temperature).