A novel mediator-free biosensor was constructed by the co-intercalation of negatively charged DNA and positively charged hemoglobin (Hb) in the interlayer galleries of layered α-zirconium phosphate (α-ZrP) with the delamination-assembly procedure at pH 5.5. X-ray diffraction and field-emission scanning electron microscopy results revealed the featured layered structure for the re-assembled DNA/Hb/α-ZrP composite. Infrared spectroscopy and circular dichroism results confirmed the coexistence of Hb and DNA in the composite and the considerably retained protein conformation of intercalated Hb. The direct electron transfer of Hb was facilitated by the co-intercalation of DNA and Hb. Because of the synergistic effect of α-ZrP host and co-intercalated DNA guest, the DNA/Hb/α-ZrP modified electrode exhibited good electrocatalytic response to H2O2 with higher sensitivity of 0.79 A M−1 cm−2 and lower detection of 4.28 × 10−7 M in the linear range of 7.28 × 10−7 to 9.71 × 10−5 M. Furthermore, the electrocatalytic activity of Hb in the DNA/Hb/α-ZrP composite retained at high temperature (85 °C) or in the presence of organic solvent (CH3CN), which could be the protection of α-ZrP nanosheets.

A novel azobenzene-derived amphiphile with a melamine head, 2Azo-2C12H25-melamine, has been synthesized. π−A isotherm measurements displayed that this amphiphile is able to form a stable Langmuir monolayer on both pure water and barbituric acid (BA)- or thymine (T)-containing subphases. The collapse surface pressure and limiting molecular area of its Langmuir monolayer on pure water are 40 mN/m and 0.56 nm2, respectively. However, when barbituric acid or thymine was introduced into the subphase, the corresponding π−A isotherms of the monolayers exhibited a lower collapse surface pressure (22 mN/m for BA, 21 mN/m for T) and smaller limiting molecular area (0.54 nm2 for BA and 0.52 nm2 for T). UV−vis and FT-IR studies of the LB films formed by 2Azo-2C12H25-melamine have also been carried out. The results indicated that the LB films of 2Azo-2C12H25-melamine deposited from pure water undergo distinct collapse of the H-aggregate upon UV irradiation, while the LB films deposited from a BA- or T-containing subphase retain the H-aggregate. The host−guest-interaction-induced blockage of azobenzene photoisomerization should be responsible for the stabilized H-aggregate. A 1:1 host/guest binding mode to form a linear supramolecular polymeric chain has been proposed in the Langmuir monolayers formed on a BA- or T-containing subphase. The current results suggest that the host−guest interaction should be an effective means to manipulate the interfacial assembly of azobenzene-derived amphiphiles.