We have shown that integrating cellulose derived carbon dots (CD) and reduced CD (r-CD) to common bioplastics or bioresorbable materials, such as poly(lactide) (PLA) and poly(caprolactone) (PCL) can enhance the material properties and induce new properties as bioactivity. The CD (~22 nm) were obtained via oxidation of carbon spheres produced from hydrothermal carbonization of cellulose. An additional facile hydrothermal approach was developed to reduce the CD into r-CD (~12 nm) with the aid of caffeic acid. The reduction led to a C/O ratio of 3.3 for r-CD, whereas the ratio was 1.0 for CD. Good adhesion between CD and PLA was proven successfully as measured by atomic force microscopy colloidal probe. The adhesion force between PLA and CD (234.8 nN) was significantly greater compared to graphene oxide (GO) (80.4 nN), which resulted in better dispersion of CD. As a result, the strength and ductility, as well as hydrolytic degradation, was enhanced in the PLA/CD nanocomposite compared to neat PLA and PLA/GO. In addition, PLA/CD showed high transparency and worked as a good barrier against oxygen. It was further shown that added CD/r-CD in PCL worked as nucleation points for mineralization on the surface of PCL nanocomposite. As compared to CD, r-CD had better interactions with PCL leading to ductile nanocomposites with improved storage modulus compared to neat PCL. Promisingly, the cytotoxicity of r-CD was also low towards osteoblastic-like MG63 cells at a concentration of up to 200 ug/mL. These works demonstrated that renewable resource derived CD enabled multifunctional mechanically improved nanocomposites. References: 1. RSC Adv. 2015, 5, 26550-26558 2. ACS Sustainable Chem. Eng. 2016, 4, 5618-5631 3. Biomacromolecules. 2015, 17, 256-261 4. ACS Sustainable Chem. Eng. 2018, 6, 1246-1255 5. Biomacromolecules. 2018, 19, 1074-1081