This review provides a systematic overview of the complicated antibacterial and antibiofilm mechanisms of carbon dots.

Carbon quantum dots derived from gentamicin sulfate are directly developed by facile calcination at different temperatures. A promising nanomaterial, CQD₁₈₀, even shows a much superior antibacterial activity compared with the antibiotic counterpart and low drug resistance, by preserving the active structure of the starting materials and providing an additional antibacterial mode arising from the positive charge surface and induced reactive oxygen species simultaneously. Moreover, CQD₁₈₀ can effectively disrupt mature Staphylococcus aureus biofilm and selectively eliminate bacteria over mammalian cells.

Implant-associated infection is a major threat affecting the success of orthopedic surgeries. Although various materials scavenge bacteria by generating reactive oxygen species (ROS), the intrinsic inability of ROS to distinguish bacteria from cells notably limits the therapeutic effects. Here, we found that the arginine carbon dots (Arg-CDs) that were transformed from arginine exhibited supreme antibacterial and osteoinductive activity. We further designed the Schiff base bond between Arg-CDs and aldehyde hyaluronic acid/gelatin methacryloyl (HG) hydrogel to release Arg-CDs in response to the acidic bone injury microenvironment. The free Arg-CDs could selectively kill bacteria by generating excessive ROS. Furthermore, the Arg-CD–loaded HG composite hydrogel showed excellent osteoinductive activity through inducing the M2 polarization of macrophages by up-regulating interleukin-10 ( Il10 ) expression. Together, our findings revealed that transformation of the arginine into zero-dimensional Arg-CDs could endow the material with exceptional antibacterial and osteoinductive activity, favoring the regeneration of infectious bone.