Biocomposites derived from wood-based materials exhibit complex interfacial structures that critically influence their mechanical and physicochemical properties. Solid-state NMR spectroscopy enhanced by Dynamic Nuclear Polarization (DNP) has emerged as a powerful tool to probe such interfaces at the molecular level by significantly boosting signal sensitivity. In this study, we employ DNP-NMR to characterize the interfacial regions of wood-based biocomposites, focusing on the in-situ addition of DNP radicals within the system. DNP is based on a microwave-induced transfer of the spin polarisation of unpaired electrons in the sample. To date, high-field DNP studies of materials have mainly used exogenous organic radicals introduced into materials by post-impregnation with radical-containing solutions [1,2,3]. By instead introducing radicals during composite formulation, we aim to achieve homogeneous radical dispersion, mitigating the need for post-synthetic radical impregnation. Based on the selection of a model biocomposite, the strategy is to use either radicals added during the processing stages (solvent casting, spray drying, extrusion, hot pressing) or radicals incorporated by chemical reaction (oxidation of conjugated polymers). The effectiveness of these biocomposite radical systems will then be assessed using DNP-NMR and Electron Paramagnetic Resonance (EPR) spectroscopies. High Resolution NMR will also be performed to assess molecular size changes through diffusion-ordered spectroscopy (DOSY) to ensure proper composite formation. This approach facilitates direct polarization transfer to interfacial domains, improving spectral resolution and enabling the identification of chemical interactions between cellulosic components and matrix biopolymers. Our methodology provides new insights into the fundamental chemistry of biocomposite interfaces, paving the way for advanced material design and improved functional performance.