Photoactivated multifunctional nanoplatform based on lysozyme-Au nanoclusters-curcumin conjugates with FRET effect and multiamplified antimicrobial activity

Controllable Preparation of a Cu NCs@Zn-MOF Hybrid with Dual Emission Induced by an Ion Exchange Strategy for the Detection of Explosives

The precise synthesis of Cu NCs is a highly desirable and controllable route for the preparation of desired structures and properties, which facilitates the rational design of valuable probes for fluorescence sensing and the understanding of structure-property relationships. Herein, an ion-exchange strategy combined with a bottom-up synthetic approach was utilized in the synthesis process of Cu NCs for the first time, which achieved the controllable synthesis of Cu NCs and in situ anchoring of Cu NCs on the support material HPU-14. The as-prepared Cu NCs@HPU-14-4h not only had a good peroxidase-like property but also exhibited stable dual-emitting fluorescence at 470 and 620 nm. Notably, the peroxidase-like property endowed Cu NCs@HPU-14-4h with the capability of highly sensitive colorimetric detection of H2O2 in a linear concentration from 0.1 to 140 μM (detection limit of 86.7 nM), and a change in the fluorescent color from red to blue could be observed by the naked eye. Furthermore, due to the large overlap between the absorption of 2,4,6-trinitrophenol (TNP) and the excitation band of Cu NCs@HPU-14-4h, TNP could also be detected from 27 types of analogs and common ions with a limit of detection of 68 nM. Finally, a portable hydrogel probe with efficient wipe sampling was fabricated by polyvinyl alcohol (PVA) comprising Cu NCs@HPU-14-4h with the aim of on-site visualization of different explosives. Consequently, the current study not only provides a new idea for the precise synthesis of Cu NCs and their controllable anchoring on support materials but also offers an effective method for predicting H2O2 and TNP.

Cur@ZIF-8@BA nanomaterials with pH-responsive and photodynamic therapy properties promotes antimicrobial activity

Antimicrobial photodynamic therapy (aPDT) has emerged as a highly promising strategy for non-antibiotic treatment of infections due to its unique advantages in efficient bactericidal action and reduction of drug resistance. The natural photosensitizing properties of curcumin (Cur) are widely acknowledged; however, its limited bioavailability has impeded its practical application. In this study, we developed a nanomaterial called Cur@ZIF-8@BA by encapsulating Cur within ZIF-8 and modifying the surface with boric acid (BA). The Cur@ZIF-8@BA exhibits pH-responsive properties and enhances bacterial binding, thereby effectively promoting photodynamic therapy. Moreover, its antibacterial activity against E. coli, Staphylococcus aureus and A. baumannii is significantly increased in the presence of light compared to a dark environment. The mechanism behind this may be that BA increases the affinity of Cur@ZIF-8@BA towards bacteria, and making released Zn2+ and BA from the nanomaterial increase bacterial cell membrane permeability. This facilitates efficient delivery of Cur into bacterial cells, resulting in generation of abundant reactive oxygen species (ROS) and subsequent bactericidal activity. In conclusion, our prepared Cur@ZIF-8@BA holds great promise as a photodynamically mediated antimicrobial strategy.

Mix and Shake: A Mild Way to Drug-Loaded Lysozyme Nanoparticles

Biocompatible nanoparticles as drug carriers can improve the therapeutic efficiency of hydrophobic drugs. However, the synthesis of biocompatible and biodegradable polymeric nanoparticles can be time-consuming and often involves toxic solvents. Here, a simple method for protein-based stable drug-loaded particles with a narrow polydispersity is introduced. In this process, lysozyme is mixed with hydrophobic drugs (curcumin, ellipticine, and dasatinib) and fructose to prepare lysozyme-based drug particles of around 150 nm in size. Fructose is mixed with the drug to generate nanoparticles that serve as templates for the lysozyme coating. The effect of lysozyme on the physicochemical properties of these nanoparticles is studied by transmission electron microscopy (TEM) and scattering techniques (e.g., dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS)). We observed that lysozyme significantly stabilized the curcumin fructose particles for 7 days. Moreover, additional drugs, such as ellipticine and dasatinib, can be loaded to form dual-drug particles with narrow polydispersity and spherical morphology. The results also reveal that lysozyme dual ellipticine/dasatinib curcumin particles enhance the cytotoxicity and uptake on MCF-7 cells, RAW 264.7 cells, and U-87 MG cells due to the larger and rigid hydrophobic core. In summary, lysozyme in combination with fructose and curcumin can serve as a powerful combination to form protein-based stable particles for the delivery of hydrophobic drugs.

Polydopamine-curcumin coating of titanium for remarkable antibacterial activity via synergistic photodynamic and photothermal properties

Combined photothermal therapy (PTT) and photodynamic therapy (PDT) has emerged as a novel and effective antibacterial strategy. In order to endow titanium (Ti) with antibacterial properties, the Ti-PDA-Cur composite was prepared using the excellent adhesion properties of polydopamine (PDA) to load curcumin (Cur) on the surface of Ti. The Ti-PDA-Cur coating can produce singlet oxygen (1O2) and heat under 405 + 808 nm light irradiation, which can effectively kill Staphylococcus aureus and Escherichia coli. Moreover, the cytotoxicity and hemolysis rate of Ti-PDA-Cur were low, indicating its good biocompatibility. Therefore, this study provided a new strategy for the development of new Ti implants.

Characteristics of hen egg white lysozyme, strategies to break through antibacterial limitation, and its application in food preservation: A review

Hen egg white lysozyme (HEWL) is used as a food additive in China due to its outstanding antibacterial properties. It is listed as GRAS grade (generally recognized as safe) by the United States Food and Drug Administration (FDA, US) and has been extensively researched and used in food preservation. And the industrial production of HEWL already been realized. Given the complex food system that can affect the antibacterial activity of HEWL, and the limitations of HEWL itself on Gram-negative bacteria. Based on the structure and main biological characteristics of HEWL, this paper focuses on reviewing methods to enhance the stability and antibacterial properties of HEWL. Immobilization tactics such as chemically driven self-assembly, embedding and adsorption address the restriction of poor HEWL antibacterial activity effected by external factors. Both intermolecular and intramolecular modification strategies break the bactericidal deficiencies of HEWL itself. It also comprehensively analyzes the current application status and future prospects of HEWL in the food preservation. There was limited research on the biological methods in modifying HEWL. If the HEWL is genetically engineered, it can broaden its antimicrobial spectrum, improve its other biological activities, so as to further expand its application in the food industry. At present, research on HEWL mainly focused on its antibacterial properties, whereas its application in anti-inflammatory and antioxidant effects also presented great potential.

In vitro study of nanoliposomes containing curcumin and doxycycline for enhanced antimicrobial photodynamic therapy against Aggregatibacter actinomycetemcomitans

The excessive inappropriate use of systemic antibiotics has contributed to the emergence of antibiotic-resistant pathogens, which pose a significant risk to the success of treatment. This study has approached this problem by developing doxycycline-loaded liposome doped with curcumin (NL-Cur^+Dox) for combination antibacterial therapy against Aggregatibacter actinomycetemcomitans. The characterization of formulation revealed encapsulation of both drugs in NL-Cur^+Dox with an average size of 239 nm and sustained release behavior. Transmission electron microscopy analysis confirmed the vesicular-shaped nanocarriers without any aggregation or crystallization. The cytotoxic and hemolytic activities of NL-Cur^+Dox were evaluated. The anti-biofilm and anti-metabolic effects of NL-Cur^+Dox -mediated antimicrobial photodynamic therapy (aPDT) were examined. The data indicated that NL-Cur^+Dox -mediated aPDT led to a significant reduction of biofilm (82.7%, p = 0.003) and metabolic activity (75%, p < 0.001) of A. actinomycetemcomitans compared to the control. NL-Cur^+Dox had no significant cytotoxicity to human gingival fibroblast cells under selected conditions (p = 0.074). In addition, the hemolytic activity of NL-Cur^+Dox were negligible (< 5%). These findings demonstrate the potential application of such potent formulations in reducing one of the main bacteria causing periodontitis where the NL-Cur^+Dox could be exploited to achieve an improved phototherapeutic efficiency.

Green synthesis and multifunctional applications of nitrogen-doped carbon quantum dots via one-step hydrothermal carbonization of Curcuma zedoaria

Low-dimensional (<10 nm) semiconductor carbon quantum dots (CQDs) have been widely used in metal ion sensing and bioimaging. Here, we used the renewable resource Curcuma zedoaria as a carbon source and prepared green carbon quantum dots with good water solubility by a hydrothermal method without any chemical reagent. At different pH values (4-6) and high NaCl concentrations, the photoluminescence of the CQDs was very stable, which indicated that they were suitable for a wide range of applications even under harsh conditions. The CQDs exhibited fluorescence quenching in the presence of Fe³⁺ ions, indicating their application potential as fluorescence probes for the sensitive and selective detection of Fe³⁺ ions. The CQDs showed high photostability, low cytotoxicity, and good hemolytic activity, and were successfully applied to bioimaging experiments, i.e. multicolor cell imaging in L-02 (human normal hepatocytes) and CHL (Chinese hamster lung) cells with and without Fe³⁺, as well as wash-free labeling imaging of Staphylococcus aureus and Escherichia coli. The CQDs also showed good free radical scavenging activity and demonstrated a protective effect against photooxidative damage to L-02 cells. These results indicate that CQDs obtained from medicinal herb sources have multiple potential applications in the fields of sensing, bioimaging, and even disease diagnosis.

Turmeric carbon quantum dots enhanced chitosan nanocomposite films based on photodynamic inactivation technology for antibacterial food packaging

The increased demand for food quality and safety has led the food industry to pay urgent attention to new packaging materials with antimicrobial activity. In this study, we combined photodynamic inactivation of bactericidal technology in food packaging materials by incorporating fluorescent carbon quantum dots (CDs) prepared from the natural plant turmeric into a chitosan matrix to prepare a series of active composite food packaging films (CDs-CS). The chitosan film containing CDs had better mechanical properties, UV protection and hydrophobicity. Under irradiation with a 405 nm light source, the composite film was able to produce abundant reactive oxygen species, and the CDs-CS₂ film exhibited reductions of approximately 3.19 and 2.05 Log₁₀ CFU/mL for Staphylococcus aureus and Escherichia coli respectively within 40 min. In cold pork storage applications, CDs-CS₂ films showed inhibition of the growth of colonization in pork and retarded the spoilage of pork within 10 days. This work will provide new insights to explore safe and efficient antimicrobial food packaging.

Title: Advances of Gold Nanoclusters for Bioimaging

Gold nanoclusters (AuNCs) have become a promising material for bioimaging detection because of their tunable photoluminescence, large Stokes shift, low photobleaching, and good biocompatibility. Last decade, great efforts have been made to develop AuNCs for enhanced imaging contrast and multimodal imaging. Herein, an updated overview of recent advances in AuNCs was present for visible fluorescence (FL) imaging, near-infrared fluorescence (NIR-FL) imaging, two-photon near-infrared fluorescence (TP-NIR-FL) imaging, computed tomography (CT) imaging, positron emission tomography (PET) imaging, magnetic resonance imaging (MRI), and photoacoustic (PA) imaging. The justification of AuNCs applied in bioimaging mentioned above applications was discussed, the performance location of different AuNCs were summarized and highlighted in an unified parameter coordinate system of corresponding bioimaging, and the current challenges, research frontiers, and prospects of AuNCs in bioimaging were discussed. This review will bring new insights into the future development of AuNCs in bio-diagnostic imaging.