Surface modification of MCM-41 and its application in DNA adsorption

A new application of inorganic sorbent for biomolecules: IMAC practice of Fe3+-nano flowers for DNA separation

Selection of purification method and type of adsorbent has high significance for separation of a biomolecule like deoxyribonucleic acid (DNA). Nanoflowers are a newly improved class of adsorbent. Due to showing very structural similarity to plant flowers, they are named as nanoflowers. Herein, after synthesize of copper phosphate three hydrate nanoflowers [(Cu₃(PO₄)₂.3H₂O), CP-NFs], Fe³⁺ ions were attached to their surfaces. Obtained Fe³⁺-CP-NFs, before investigation of some adsorption parameters for DNA, they were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Some attained data from the results of adsorption experiments as follows: While maximum DNA adsorption on Fe³⁺-CP-NFs was found as an excellent value of 845.8 mg/g, nanoflowers without Fe³⁺ ions adsorbed DNA as only 25.3 mg/g. Optimum media conditions for DNA adsorption were observed at pH 7 and 25 °C with an initial concentration of 1.5 mg/mL DNA. Langmuir and Freundlich adsorption equations were applied to determine which adsorption model was appropriate, and it was seen that Langmuir model was fit with a R² of 0.9885.

Exploring encapsulation mechanism of DNA and mononucleotides in sol-gel derived silica

The encapsulation mechanism of DNA in sol-gel derived silica has been explored in order to elucidate the effect of DNA conformation on encapsulation and to identify the nature of chemical/physical interaction of DNA with silica during and after sol-gel transition. In this respect, double stranded DNA and dAMP (2'-deoxyadenosine 5'-monophosphate) were encapsulated in silica using an alkoxide-based sol-gel route. Biomolecule-encapsulating gels have been characterized using UV-Vis, ²⁹Si NMR, FTIR spectroscopy and gas adsorption (BET) to investigate chemical interactions of biomolecules with the porous silica network and to examine the extent of sol-gel reactions upon encapsulation. Ethidium bromide intercalation and leach out tests showed that helix conformation of DNA was preserved after encapsulation. For both biomolecules, high water-to-alkoxide ratio promoted water-producing condensation and prevented alcoholic denaturation. NMR and FTIR analyses confirmed high hydraulic reactivity (water adsorption) for more silanol groups-containing DNA and dAMP encapsulated gels than plain silica gel. No chemical binding/interaction occurred between biomolecules and silica network. DNA and dAMP encapsulated silica gelled faster than plain silica due to basic nature of DNA or dAMP containing buffer solutions. DNA was not released from silica gels to aqueous environment up to 9 days. The chemical association between DNA/dAMP and silica host was through phosphate groups and molecular water attached to silanols, acting as a barrier around biomolecules. The helix morphology was found not to be essential for such interaction. BET analyses showed that interconnected, inkbottle-shaped mesoporous silica network was condensed around DNA and dAMP molecules.