Phenol/Chloroform-Free TiO₂-Based miRNA Extraction from Cell Lysate

While microRNAs are considered as excellent biomarkers of various diseases, there are still several remaining challenges regarding their isolation. In this study, we aimed to design a novel RNA isolation method that would help to overcome those challenges. Therefore, we present a novel phenol/chloroform-free, low-cost method for miRNA extraction. Within this method, RNA is extracted from cell lysate with an isopropanol/water/NaCl system, followed by solid-phase extraction using TiO₂ microspheres to effectively separate short RNAs from long RNA molecules. We also demonstrated the pH-dependent selectivity of TiO₂ microspheres towards different sizes of RNA. We were able to regulate the size range of extracted RNAs with simple adjustments in binding conditions used during the solid-phase extraction.