Porous Cellulose Nanofiber-based Microcapsules for Biomolecular Sensing

Cellulose nanofibers (CNFs) have recently attracted a lot of attention in sensing because of its multifunctional character and properties such as renewability, non-toxicity, biodegradability, printability and optical transparency in addition to its unique physicochemical, barrier and mechanical properties. However, the focus has exclusively been devoted towards developing 2D sensing platforms in the form of nanopaper or nanocellulose-based hydrogels. To improve flexibility and sensing performance in situ, e.g. to detect biomarkers in vivo for early disease diagnostics, more advanced CNF-based structures are needed. Here, we developed porous and hollow, yet robust, CNF-based microcapsules using only the primary plant cell wall components, CNF, pectin and xyloglucan, to assemble the capsule wall. FITC-labelled dextrans with MW of 70 kDa and 2000 kDa could enter the hollow capsules at a rate of 0.13 ± 0.04 s-1 and 0.014 ± 0.009 s-1, respectively. This property is very attractive because it minimizes the infl...