Aggregation Behavior of the Template-Removed 5,10,15,20-Tetrakis(4-sulfonatophenyl)porphyrin Chiral Array Directed by Poly(ethylene glycol)-<i>block</i>-poly(l‑lysine)

Complexation between 5,10,15,20-tetrakis­(4-sulfonatophenyl)­porphyrin (TPPS) and poly­(ethylene glycol)-<i>block-</i>poly­(l-lysine) (PEG-<i>b</i>-PLL) was performed via electrostatic interaction. Two kinds of primary arrays of TPPS with different supramolecular chirality induced by PLL were obtained in the resultant complex by inverting the mixing procedure of the two components. These arrays could be displaced by poly­(sodium-<i>p</i>-styrenesulfonate) (PSS) from the chiral PLL template through competitive electrostatic complexation, and then PSS formed a polyion complex micelle with PEG-<i>b</i>-PLL. The template-removed TPPS arrays preserved their induced chirality and served as primary subunits for the secondary aggregation of TPPS. The morphology of the secondary aggregates was strongly dependent upon the asymmetric primary supramolecular arrangement of TPPS. The rodlike nanostructure that was ∼200 nm in length was composed of the primary arrays that showed opposite exciton chirality between the J- and H-bands. In contrast, the micrometer-sized fibrils observed were composed of the arrays with the same exciton chirality at the J- and H-bands

Assessing the Redox Toxicity of 2D Nanosheets Based on Their Redox Effect on Cytochrome <i>c</i> in Microchannels

2D nanosheets (NSs) have been widely used in drug-related applications. However, a comprehensive investigation into the cytotoxicity mechanism linked to the redox activity is lacking. In this study, with cytochrome c (Cyt c) as the model biospecies, the cytotoxicity of 2D NSs was evaluated systematically based on their redox effect with microfluidic techniques. The interface interaction, dissolution, and redox effect of 2D NSs on Cyt c were monitored with pulsed streaming potential (SP) measurement and capillary electrophoresis (CE). The relationship between the redox activity of 2D NSs and the function of Cyt c was evaluated in vitro with Hela cells. The results indicated that the dissolution and redox activity of 2D NSs can be simultaneously monitored with CE under weak interface interactions and at low sample volumes. Both WS2 NSs and MoS2 NSs can reduce Cyt c without significant dissolution, with reduction rates measured at 6.24 × 10–5 M for WS2 NSs and 3.76 × 10–5 M for MoS2 NSs. Furthermore, exposure to 2D NSs exhibited heightened reducibility, which prompted more pronounced alterations associated with Cyt c dysfunction, encompassing ATP synthesis, modifications in mitochondrial membrane potential, and increased reactive oxygen species production. These observations suggest a positive correlation between the redox activity of 2D NSs and their redox toxicity in Hela cells. These findings provide valuable insight into the redox properties of 2D NSs regarding cytotoxicity and offer the possibility to modify the 2D NSs to reduce their redox toxicity for clinical applications