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.

Magnetic Resonance Imaging (MRI) has been recently applied to decipher the complex flow of dry granular materials, which play an important role in a variety of chemical engineering applications. In these materials, the short apparent transverse relaxation time of the constituent grains, T₂^∗, leads to rapid signal decay and hence limits the choice of suitable pulse sequences. While oil-rich agricultural seeds and oil-filled core–shell particles containing substantial amounts of liquids have been used to generate MRI signals, these particles still suffer from T₂^∗ values much shorter than the transverse relaxation time T₂ of the contained liquid. This work investigates the effect of magnetic susceptibility on T₂^∗ through numerical simulations and experiments. Numerical results demonstrate that matching the magnetic susceptibility of the particles, χ_p, to that of the air between them, χ_air, reduces dipolar magnetic field inhomogeneities, theoretically enabling T₂^∗=T₂. We also found that common imperfections in core–shell particles — such as asphericity, non-concentricity of core and shell, and uneven shell thickness — cause significant field inhomogeneities. These inhomogeneities can only be mitigated if both the core and shell materials have a magnetic susceptibility matching that of air. Based on these findings, we designed and manufactured core–shell particles with doped cyclooctane (CO) encapsulated in doped gelatin with χ_core≈χ_shell≈χ_air. These particles exhibited a T₂^∗ of 3.85 ms, more than twice that of previously available materials, thus improving the signal-to-noise ratio and enhancing pulse sequence flexibility. This advancement opens up new possibilities for applications in engineering and the study of granular physics.

Stimuli-responsive gels demonstrate macroscopic changes upon exposure to external stimuli, offering potential for the development of adaptive chemical reactors. Early investigations into hydrogels established that crosslinked polymer networks experience reversible volume phase transitions, with temperature, pH, and solvent composition governing swelling and shrinking dynamics. Although hydrogels behavior in aqueous environments has been extensively characterized, lyogels that incorporate organic solvents remain comparatively underexplored, despite their potential for enhanced chemical compatibility and functional versatility. Here, we investigate how solvent polarity and crosslinking density govern the swelling behavior, pore formation, and molecular-scale dynamics of poly(N-isopropylacrylamide)-based lyogels. Using a combination of swelling measurement, scanning electron microscopy, and multiscale NMR relaxometry and diffusometry, we demonstrate that solvent polarity fundamentally alters lyogel structure and dynamics. Lyogels swollen in a high-polarity solvent exhibits macroporous networks and slower solvent exchange rates, whereas a low-polarity solvent induces shrinkage, denser microstructures, faster solvent exchange rates, and stronger surface interactions. These results establish a mechanistic framework linking thermodynamic affinity, solvent dynamics, and microstructural confinement to macroscopic gel responsiveness. This framework provides guidance for tailoring lyogels in dynamic environments, with potential applications in adaptable and tunable chemical reactors.