Interaction thermodynamics studies of different surface-modified ZnSe QDs with BSA by spectroscopic and molecular simulation methods

Albumin as a functional carrier enhances solubilization, photodynamic and photothermal antibacterial therapy of curcumin

Bacterial infections are a significant threat to human health. Photodynamic therapy (PDT) and photothermal therapy (PTT) offer promising alternatives to antibiotic therapy. Curcumin (CUR) has shown great potentials in PDT, but its PTT was never reported. Also, its delivery and efficacy is highly limited by the poor water solubility. Herein, we report the antibacterial PTT of CUR for the first time. Furthermore, we successfully solubilized CUR, facilitated its delivery into bacterial cells, and enhanced its antibacterial PDT/PTT via using bovine serum albumin (BSA) as a carrier. The water solubility of CUR was enhanced from 10 to 298 μg/mL by forming CUR-BSA complex (containing 4 mg/mL BSA) which also enhanced the delivery of CUR into E. coli cells by >10 folds. Upon 450 nm irradiation, CUR-BSA (80 μg/mL) caused 94 % viability loss of E. coli, higher than 70 % loss caused by CUR, and more intracellular ROS was generated in CUR-BSA group. Interestingly, the antibacterial activity of CUR-BSA was reduced when the hyperthermia was depleted, suggesting its synergistic PDT/PTT effect. Considering the ready availability and great biocompatibility of albumin, our findings indicate that CUR-albumin complex may have great potentials in clinical use for antibacterial phototherapy.

A Comparative Study of Nanobio Interaction of Zn-Doped CdTe Quantum Dots with Lactoferrin Using Different Spectroscopic Methods

In this paper, glutathione (GSH)-coated Zn-doped CdTe quantum dots (QDs) with different particle sizes were synthesized using the "reflow method", and the interaction mechanism between the two QDs and lactoferrin (LF) was investigated systemically with different spectroscopic methods. The steady-state fluorescence spectra showed that the LF formed a tight complex with the two QDs through static bursting and that the electrostatic force was the main driving force between the two LF-QDs systems. The complex generation process was found to be spontaneous (ΔG < 0) and accompanied by exothermic and increasing degrees of freedom (ΔH < 0, ΔS > 0) by using the temperature-dependent fluorescence spectroscopy. The critical transfer distance (R₀) and donor-acceptor distance (r) of the two LF-QDs systems were obtained based on the fluorescence resonance energy transfer theory. In addition, it was observed that the QDs changed the secondary and tertiary structures of LF, leading to an increase in the hydrophobicity of LF. Further, the nano-effect of orange QDs on LF is much larger than that of green QDs. The above results provide a basis for metal-doped QDs with LF in safe nano-bio applications.