Enzyme Tagged Poly (Acrylic Acid)‐ <i>grafted‐</i> Nanoparticles: A Unique Strategy to Improve Stability and Activity of Enzyme

ABSTRACT The application of enzymes in biocatalytic and biomedical technologies remains challenging due to their intrinsic instability, despite evidence that immobilization on solid supports enhances stability and reusability. Herein, we report a simple strategy for covalent immobilization of urease, an enzyme with inherently poor stability at ambient temperature, onto silica nanoparticle surfaces grafted with poly(acrylic acid) (pAA‐ g ‐SiNPs) via reversible addition‐fragmentation chain transfer polymerization. The resulting hybrid materials offer a high density of surface carboxyl functionalities enabling efficient urease conjugation, yielding a stable biocatalytic material (pAA‐ g ‐SiNPs/U). Kinetic studies of urea hydrolysis confirmed that immobilized urease retained catalytic activity for nearly one month under ambient conditions, in contrast to free urease, which losses catalytic activity within 2–5 days when stored in ambient temperature. Moreover, pAA‐ g ‐SiNPs/U exhibited excellent operational stability, maintaining activity after multiple catalytic cycles and under alkaline pH and elevated temperatures up to 60 °C. This enhanced performance proves the ability of the hybrid polymer‐silica platform to mitigate enzymatic denaturation while extending functional shelf‐life. Our approach offers a simple and versatile route for preserving enzymes at room temperature, thereby facilitating their translation into biomedical applications and enabling their use as recyclable heterogeneous biocatalysts.