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Tooth staining and biofilm formation are major challenges for dental healthcare around the world. Herein, a bifunctional photodynamic dental therapy (PDDT) strategy is designed based on zwitterion-modified porphyrin (ZMP) prepared by the conjugation of protoporphyrin IX (PP) and a superhydrophilic zwitterion moiety for tooth whitening and biofilm eradication. The electron donor-acceptor structure and water solubility of ZMP increases its reactive oxygen species output to ≈8 times compared with PP under purple light irradiation. Results show that this new strategy can not only nondestructively whiten teeth by degrading the chromogen, but also eradicate ≈95% of the biofilm by disintegrating the extracellular polymeric substances. This study highlights the superiority of ZMP as a photosensitizer and opens new avenues in exploring PDDT for clinical dentistry to whiten teeth and treat biofilm-induced dental diseases.

Recently, genkwanin (GKA) has been shown to display in vitro antitumor activity against some cancer cells, but its poor solubility restricted the in vivo study and further investigation of its antitumor therapeutic efficacy. In this paper, genkwanin nanosuspensions (GKA-NSps) were successfully prepared using D-alpha tocopherol acid polyethylene glycol succinate (TPGS) as a stabilizer using the precipitation-homogenization method. The obtained GKA-NSps had an average particle size of 183.1 ± 4.4 nm, a PDI value of 0.16 ± 0.07, a zeta potential of -16.2 ± 0.1 mV, and a drug loading content of 49.36 ± 0.14%. GKA-NSps showed spherical morphology and very good stability in normal saline, phosphate buffer saline (PBS, pH 7.4), 5% glucose, artificial gastric juice, artificial intestinal juice and plasma; thus, it is suitable for both oral and intravenous administration. The resultant GKA-NSps displayed sustained drug release behavior and stronger in vitro cytotoxicity against 4T1, MCF-7, MDA-MB-453, HeLa, HepG2, BT474, and A549 cells than free GKA. The in vivo study in MCF-7 tumor-bearing nude mice indicated that GKA-NSps (60 mg/kg, i.v.) achieved similar therapeutic efficacy as PTX injection (8 mg/kg, i.v.) (62.09% vs. 61.27%), while the minimal lethal dose was more than 320 mg/kg, indicating good safety. By using nanotechnology, our study suggested that some antitumor flavonoids of low potency, such as GKA, are promising as safe but effective anticancer drugs.

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In order to achieve the purpose of targeting treatment of osteosarcoma, we developed novel paclitaxel (PTX) nanoparticles (Nps) coated with polydopamine (PDA) and grafted by alendronate (ALN) as ligand. Dopamine can be easily polymerized on various surfaces to form a thin PDA film in alkaline environment, which provided a versatile platform to perform secondary reactions for compounds without functional groups. The targeting Nps had a mean particle size of 290.6 ± 2.2 nm and a zeta potential of −13.4 ± 2.7. It was stable in phosphate buffer saline (PBS, pH 7.4), 5% glucose, plasma and displayed sustained drug release behavior. In vitro assay demonstrated the targeting Nps had stronger cytotoxicity against K7M2 wt osteosarcoma cells than the non-targeting Nps. Furthermore, in vivo distribution study indicated they could accumulate much more in tumor than non-targeting Nps. This is consistent with the in vivo antitumor study, targeting Nps achieved a better therapeutic effect than Taxol (8 mg kg−1, i.v.) (71.85% versus 66.53%) and prominently decreased the side effects of PTX. In general, the PTX-PDA-ALN-Nps may offer a feasible and effective strategy for osteosarcoma targeted therapy.