The large number of deaths induced by carcinoma and infections indicates that the need for new, better, targeted therapy is higher than ever. Apart from classical treatments and medication, photodynamic therapy (PDT) is one of the possible approaches to cure these clinical conditions. This strategy offers several advantages, such as lower toxicity, selective treatment, faster recovery time, avoidance of systemic toxic effects, and others. Unfortunately, there is a small number of agents that are approved for usage in clinical PDT. Novel, efficient, biocompatible PDT agents are, thus, highly desired. One of the most promising candidates is represented by the broad family of carbon-based quantum dots, such as graphene quantum dots (GQDs), carbon quantum dots (CQDs), carbon nanodots (CNDs), and carbonized polymer dots (CPDs). In this review paper, these new smart nanomaterials are discussed as potential PDT agents, detailing their toxicity in the dark, and when they are exposed to light, as well as their effects on carcinoma and bacterial cells. The photoinduced effects of carbon-based quantum dots on bacteria and viruses are particularly interesting, since dots usually generate several highly toxic reactive oxygen species under blue light. These species are acting as bombs on pathogen cells, causing various devastating and toxic effects on those targets.

The electrochemical exfoliation of graphite to give one-atom-thick graphene with desirable properties is a green, cost-effective method for high-yield graphene production. This paper presents the results of electrochemical exfoliation of two different graphite precursors under an applied direct current voltage of +12 V. The used characterization techniques (elemental analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-photoelectron spectroscopy, Raman spectroscopy, field emission scanning electron microscopy and atomic force microscopy) showed that the exfoliated powder is highly functionalized with a low carbon/oxygen content that is similar to graphene oxide. The exfoliated graphene sheets dispersed in N,N′-dimethylformamide were deposited on ano-discs by vacuum filtration and transferred to glass ceramic substrates. The thermal annealing of the as-deposited films at 600 °C for 30 minutes resulted in an increase in the carbon/oxygen ratio by more than 3 fold and a decrease in the sheet resistance by 25%. The lowest values for the sheet resistance of the annealed graphene thin films were in the range of 0.32 ± 0.04 to 0.84 ± 0.1 kohm sq⁻¹ depending on the graphite source that was used.