Chitosan/bacterial cellulose composite films containing diamond nanoparticles (NDs) with potential application as wound dressing are introduced. Microstructural studies show that NDs are uniformly dispersed in the matrix, although slight agglomeration at concentrations above 2 wt % is seen. Fourier transform infrared spectroscopy reveals formation of hydrogen bonds between NDs and the polymer matrix. X-ray diffraction analysis indicates reduced crystallinity of the polymer matrix in the presence of NDs. Approximately 3.5-fold increase in the elastic modulus of the composite film is obtained by the addition of 2 wt % NDs. The results of colorimetric analysis show that the composite films are transparent but turn to gray-like and semitransparent at high ND concentrations. Additionally, a decrease in highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) gap is also seen, which results in a red shift and higher absorption intensity towards the visible region. Mitochondrial activity assay using L929 fibroblast cells shows that the nanocomposite films are biocompatible (>90%) after 24 h incubation. Multiple lamellapodia and cell-cell interaction are shown. The results suggest that the developed films can potentially be used as a flexible platform for wound dressing.

Relationship of the surface physicochemical characteristics of nanoparticles with their interactions with biological entities may provide critical information for nanomedicinal application. Here, we report the systematic synthesis of sub-50 nm carbon nanoparticles (CNP) presenting neutral, anionic, and cationic surface functionalities. A subset of CNPs with ~10, 20, and 40 nm hydrodynamic sizes were synthesized with neutral surface headgroups. For the first time, the cellular internalization of these CNPs was systematically quantified in various stages of breast cancer cells (early, late, and metastatic), thereby providing a parametric assessment of charge and size effects. Distinct activities were observed when these systems interacted with cancer cells in various stages. Our results indicated that metastatic breast cancer could be targeted by a nanosystem presenting anionic phosphate groups. On the contrary, for patients in late stage of cancer, drugs could be delivered with sulfonate functionalized carbon nanoparticles, which have higher probability of intracellular transport. This study will facilitate the better understanding of nanoparticle–biological entity interaction, and the integration of this knowledge with pathophysiology would promote the engineering of nanomedicine with superior likelihoods of crossing the endocytic “barrier” for drug delivery inside cancerous cells.