Removal of ribonucleases from solution using an inhibitor-based sol-gel-derived Biogel

Currently, there are no simple one-step methods available to remove ribonucleases (RNases) from solution; however, such is imperative for researchers working with ribonucleic acids (RNAs) because RNases can destroy RNA. We report a simple means to remove RNase from solution. The scheme is based on the encapsulation of a new RNase inhibitor, poly[2'-O-(2,4-dinitrophenyl)]poly-(adenylic acid) (DNP-poly(A)), within porous tetramethoxysilane-(TMOS) or tetraethoxysilane-(TEOS) based sol-gel-derived silica particles that are used to form a small bioaffinity column. We investigate the activity, binding capacity, and stability of the hybrid DNP-poly(A)/sol-gel-derived bioaffinity material. Radioactivity and fluorometric assays are used to determine the response of the sol-gel entrapped DNP-poly(A) to a variety of RNases. The results clearly demonstrate that DNP-poly(A) entrapped within the sol-gel matrix is active and binds to all RNases tested. There is minimal (< 6%) leaching of the DNP-poly-(A) from the column. The DNP-poly(A)-doped sol-gel-derived particles do not require hydrated storage conditions. Biocolumn performance and stability are comparable for DNP-poly(A)-doped TMOS- and TEOS-derived materials. Sodium chloride can be used to regenerated the DNP-poly(A) column. The binding capacity of the biocolumn decreases over time; however, the binding capacity of a 2-month-old DNP-poly(A)-doped biocolumn is several orders of magnitude greater than the typical levels of RNase encountered in contaminated solutions.