Potential antioxidant and anti-inflammatory action of Hypericum hookerianum extracts in a liposome system evaluated with zebrafish embryos

Maleimide conjugated PEGylated liposomal antibiotic to combat multi-drug resistant Escherichia coli and Klebsiella pneumoniae with enhanced wound healing potential

Antibiotic resistance is a significant threat, leaving us vulnerable to bacterial infections. Novel strategies are needed to combat bacterial resistance beyond discovering new antibiotics. This research focuses on using maleimide conjugated PEGylated liposomes (Mal-PL-Ab) to individually encapsulate a variety of antibiotics (ceftriaxone, cephalexin, doxycycline, piperacillin, ampicillin, and ceftazidime) and enhance their delivery against multi-drug resistant (MDR) bacteria like Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae). Mal-PL-Ab, with an average size of 84.2 nm ± 4.32 nm, successfully encapsulated these antibiotics with an encapsulation efficiency of 37.73 ± 3.19%. Compared to non-PEGylated liposomes (L-Ab), Mal-PL-Ab exhibited reduced toxicity in human dermal cells, emphasizing the importance of PEGylation in minimizing adverse effects. Mal-PL-Ab significantly decreased the minimum inhibitory concentration (MIC) values against both E. coli and K. pneumoniae by 9.33-fold and eightfold reduction (compared to non-PEGylated liposomes with 2.33-fold and 2.33fold reduction), respectively, indicating enhanced efficacy against MDR strains. Furthermore, in vitro scratch assay and gene expression analysis of human dermal fibroblast revealed that Mal-PL-Ab promoted cell proliferation, migration, and wound healing through upregulation of cell cycle, DNA repair, and angiogenesis-related genes. Harnessing the power of encapsulation, Mal-PL-Ab presents a novel avenue for enhanced antibiotic delivery and wound healing, potentially transcending the limitations of traditional options.

Novel concept of exosome-like liposomes for the treatment of Alzheimer's disease

Exosomes are cell-derived vesicles that act as carriers for proteins and nucleic acids, with therapeutic potential and high biocompatibility. We propose a new concept of exosome-like liposomes for controlled delivery. The goal of this work was to develop a new type of liposomes with a unique mixture of phospholipids, similar to naturally occurring exosomes but overcoming their limitations of heterogeneity and low productivity, for therapeutic delivery of bioactive compounds. Curcumin was chosen as model compound, as it is a phytochemical molecule known to have antioxidant and anti-inflammatory properties, which can protect the brain against oxidative stress and reduce β-amyloid accumulation, major hallmarks of Alzheimer's disease (AD). These new liposomes can efficiently encapsulate hydrophobic curcumin, yielding particles with a size smaller than 200 nm, and a polydispersity index lower than 0.20, which make them ideal for crossing the blood-brain barrier. These particles have a long shelf life, being stable up to 6 months. The curcumin encapsulation efficiency was higher than 85% (up to approximately 94%). Curcumin-loaded liposomes were not cytotoxic (up to 20 μM curcumin, and 200 μM of exo-liposomes), and significantly reduced oxidative stress induced in SH-SY5Y neuronal cells, indicating their potential for neuroprotection. They also do not show any toxicity and are internalized in zebrafish embryos, concentrating in lipid enriched areas, as the brain and the yolk sac. Such innovative carriers are a new effective approach to deliver drugs into the brain, as these are stable, protect the cargo and are uptaken by neuronal cells. Upon internalization, liposomes release the therapeutic biomolecules, resulting in successful neuroprotection, being a positive alternative strategy for AD therapy.

Recent development in zebrafish model for bioactivity and safety evaluation of natural products

The zebrafish is a species of freshwater fish, popular in aquariums and laboratories. Several advantageous features have facilitated zebrafish to be extensively utilized as a valuable vertebrate model in the lab. It has been well-recognized that natural products possess multiple health benefits for humans. With the increasing demand for natural products in the development of functional foods, nutraceuticals, and natural cosmetics, the zebrafish has emerged as an unprecedented tool for rapidly and economically screening and identifying safe and effective substances from natural products. This review first summarized the key factors for the management of zebrafish in the laboratory, followed by highlighting the current progress on the establishment and applications of zebrafish models in the bioactivity evaluation of natural products. In addition, the zebrafish models used for assessing the potential toxicity or health risks of natural products were involved as well. Overall, this review indicates that zebrafish are promising animal models for the bioactivity and safety evaluation of natural products, and zebrafish models can accelerate the discovery of novel natural products with potential health functions.

Facile preparation of liposome-encapsulated Zn–DTPA from soy lecithin for decorporation of radioactive actinides

Diethylenetriaminepentaacetic acid (DTPA) is an attractive decorporation agent that can enhance the excretion of radioactive actinides such as plutonium, americium, and curium after a radiological incident. However, DTPA is excreted in a short period of time after administration. Several formulations have been developed to improve DTPA pharmacokinetics properties. In this project, liposomes were prepared facilely from soy lecithin as a nanocarrier for pulmonary delivery of Zn–DTPA. Lipid hydration, reverse phase evaporation, and mechanical sonication were three methods evaluated for the preparation of liposome-encapsulated Zn-DTPA (lipo-Zn-DTPA). Mechanical sonication was the method of choice due to simple apparatus and facile preparation. Lipo-Zn–DTPA exhibited a hydrodynamic diameter of 178 ± 2 nm and a spherical shape. The loading capacity and encapsulation efficiency of Zn–DTPA were 41 ± 5 mg/g and 10% ± 1%, respectively. Lyophilization of lipo-Zn–DTPA for extended storage did not affect the amount of encapsulated drug or damage the structure of liposomes. An in vivo cytotoxicity test confirmed no serious adverse effect of Zn–DTPA encapsulated lecithin liposomes in rats.