Encapsulation of Carbon Dots in a Core–Shell Mesh through Coaxial Direct Ink Writing for Improved Crop Growth

[Image: see text] Through coaxial direct ink writing, we fabricated a core–shell mesh system for the controlled release of carbon dots (C-dots). In the core ink, we developed an ink formulation with tuned viscosity using hydroxypropyl cellulose and polyethylene glycol to host C-dots. Polycaprolactone was employed as the main shell material, in combination with sodium alginate, to control the degradation rate of the shell. We investigated the degradation profile of the 3D-printed meshes and tracked the weekly release of C-dots in an aqueous medium by spectrofluorometry. We tested the efficacy of the C-dot release on plants by placing the meshes in transparent soil with Triticum aestivum L. seeds. We observed the in vivo translocation of the C-dots in the plant using confocal microscopy. We measured the root elongation and shoot length to assess the effect of C-dots on plant growth. Our study revealed that the plants exposed to C-dots grew 2.5-fold faster than the control group, indicating that C-dots are promising nanofertilizers for aggrotech and non-toxic fluorescent biolabels for in vivo applications.