Enzyme immobilization plays a crucial role in enhancing the stability and recyclability of enzymes for industrial applications. However, traditional methods for quantifying enzyme loading within porous carriers are limited by time-consuming workflows, cumulative errors, and the inability to probe enzymes adsorbed inside the pores. In this study, we introduce Time-Domain Nuclear Magnetic Resonance (TD-NMR) relaxometry as a novel, non-invasive technique for directly quantifying enzyme adsorption within porous carriers. Focusing on epoxy methyl acrylate carriers, commonly used in biocatalysis, we correlate changes in T₂ relaxation times with enzyme concentration, leading to the development of an NMR-based pore-filling ratio that quantifies enzyme loading. Validation experiments demonstrate that TD-NMR-derived adsorption curves align closely with traditional photometric measurements, offering a reliable and reproducible alternative for enzyme quantification. The accessibility of tabletop TD-NMR spectrometers makes this technique a practical and cost-effective tool for optimizing biocatalytic processes. Furthermore, the method holds promise for real-time monitoring of adsorption dynamics and could be adapted for a wider range of carrier materials and enzymes.

In this review we explore the recent developments in the use of Magnetic Resonance Imaging (MRI) for studying granular flows. While MRI has been a valuable tool in this field for the past 40 years, recent advances in imaging hardware, reconstruction software and particles synthesis have significantly enhanced its capabilities. This article provides an overview of the current challenges of MRI and progress in the field of granular media, and gives a perspective of the possible future developments in the field.