5'-Guanosine monophosphate mediated biocompatible porous hydrogel of β-FeOOH-viscoelastic behavior, loading, and release capabilities of freeze-dried gel.

The present manuscript reports the characterization, optimization of rheological properties, and loading and release capabilities of 5'-GMP mediated β-FeOOH hydrogel. Circular dichroism (CD) analysis indicates it to contain mainly the left-handed helix similar to that of Z-DNA. The highest viscosity (>300 cP) corresponds to the sample containing 2.5 × 10(-3) mol dm(-3) of 5'-GMP (SP2H). Field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) studies indicate the freeze-dried (FD) SP2H to be porous in nature, which is also supported by its high Brunauer-Emmett-Teller (BET) surface area of 226 m(2)/g as compared to that of SP3H (75 m(2)/g). Selected area electron diffraction (SAED) analysis and Raman spectroscopy show it to contain β-FeOOH phase. The FD SP2H exhibits the high swelling ratio (326%) and loading capacity for methylene blue (MB) dye. It displays a controlled and efficient release (>90%) for optimized [MB] (2.5 × 10(-4) mol dm(-3)) in 48 h. The low toxicity of as synthesized FD SP2H nanostructures against MDA-MB-231 (breast cancer cells) up to 100 μg/mL suggests its biocompatible nature. The high porosity, surface area, % swelling, and loading and release performance of the hydrogel indicate its potential for drug delivery and other biological applications.