Enhanced antimicrobial photodynamic activity of photosensitizer encapsulated copper based metallocatanionic vesicles against E.coli using visible light

Metallosurfactant aggregates: Structures, properties, and potentials for multifarious applications

Metallosurfactants offer important scientific and technological advances due to their novel interfacial properties. As a special class of structures formed by the integration of metal ions into amphiphilic surfactant molecules, these metal-based amphiphilic molecules possess both organometallic and surface chemistries. This review critically examines the structural transitions of metallosurfactants from micelle to vesicle upon metal coordination. The properties of a metallosurfactant can be changed by tuning the coordination between the metal ions and surfactants. The self-assembled behavior of surfactants can be controlled by selecting transition-metal ions that enhance their catalytic efficiency in environmental applications by applying a hydrogen evolution reaction or oxygen evolution reaction. We present the different scattering techniques available to examine the properties of metallosurfactants (e.g., size, shape, structure, and aggregation behavior). The utility of metallosurfactants in catalysis, the synthesis of nanoparticles, and biomedical applications (involving diagnostics and therapeutics) is also explored.

Tertiary amines convert 1O2 to H2O2 with enhanced photodynamic antibacterial efficiency

Photodynamic inactivation (PDI) is a promising approach to combat the increasing global multi-drug resistance crisis. However, the very short half-life of ¹O₂ and the inevitable photobleaching of photosensitizer (PS) are the inherent drawbacks that largely compromise its therapeutic efficiency. Here, we report a ROS conversion strategy that simultaneously addresses these issues. Based on a photodynamic model system where riboflavin (RF) served as the PS, we have clearly shown that about 93.2% of ¹O₂ could be converted to hydrogen peroxide (H₂O₂) in the presence of tertiary amine. The less reactivity of H₂O₂ (v.s.¹O₂) could retard the photobleaching of riboflavin by 88.9%. Orders of magnitude extended half-life of ROS (H₂O₂v.s.¹O₂) and retarded photobleaching of RF synergistically provide a more persistent oxidization that increased the oxidation capacity of the photodynamic model system by 56.6%. Consequently, it is able to improve the therapeutic efficiencies from 89.6% to 99.1% in combating methicillinresistant S. aureus (MRSA) and from 64.0% to 92.0% in eradicating S. aureus biofilm on biomaterials within a 5-min simulated sunlight illumination. The reinforced photodynamic model system could also significantly accelerate the healing & maturing of MRSA infected skin wound as compared to that of clinically used vancomycin. The generality of "ROS conversion" among different amines and different photosensitizers have been verified. These findings may inspire many creative approaches to increase the antibacterial efficiency of current photodynamic treatments for diverse applications.

Spherical silver oxide nanoparticles for fabrication of electrochemical sensor for efficient 4-Nitrotoluene detection and assessment of their antimicrobial activity

This research article reports an economic and affordable microwave-assisted synthesis of spherical silver oxide nanoparticles (Ag₂O NPs) (80-90 nm) for an efficient electrochemical sensing of a hazardous organic pollutant 4-nitrotoluene (4-NT). Such well-characterized Ag₂O NPs were utilized to modify gold (Au) electrode in order to fabricate Ag₂O-NPs/Au sensor to detect 4-NT using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) techniques. Ag₂O-NPs/Au sensor exhibited a distinguished electrical response as a function of varying 4-NT concentration in neutral medium samples. Ag₂O-NPs/Au sensor demonstrated an ultrahigh sensitivity as 15.33 μA (μM)^-1 cm^-2, a low detection limit of 62.3 nM, and linear response in detection ranges of 0.6-5.9 μM and 37-175 μM. The sensing performance of fabricated Ag₂O-NPs/Au sensor is reproducible, reusable, selective in presence of other chemical species, and validated using real samples. The Ag₂O/Au sensor had much rapid and easy fabrication process and offered much lower LOD for 4-NT detection than many previously reported sensors. Along with efficient electrochemical activity, the spherical Ag₂O NPs also exhibit remarkable antimicrobial activity against harmful gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus) bacteria. Herein projected efficient Ag₂O-NPs/Au electrochemical sensor for 4-NT is affordable with the capability of scaling up to perform point-of-care 4-NT testing needed for successful environmental monitoring and water quality assurance.

Biological properties and conformational studies of amphiphilic Pd(II) and Ni(II) complexes bearing functionalized aroylaminocarbo-N-thioylpyrrolinate units

A series of novel palladium(II) and nickel(II) complexes of multifunctionalized aroylaminocarbo-N-thioylpyrrolinates were synthesized and characterized by analytical and spectroscopic techniques. The biological properties of the freshly prepared compounds were screened against S. aureus, B. subtilis, A. hydrophila, E. coli, and A. baumannii bacteria and antituberculosis activity against M. tuberculosis H37Rv strains. Also, the antifungal activity was studied against C. albicans, C. tropicalis, and C. glabrata standard strains. A deep conformational survey was monitored using DFT calculations with the aim to explain the importance of the final conformation in the biological experimental results.

Lipid-Based Nanovesicular Drug Delivery Systems

In designing a new drug, considering the preferred route of administration, various requirements must be fulfilled. Active molecules pharmacokinetics should be reliable with a valuable drug profile as well as well-tolerated. Over the past 20 years, nanotechnologies have provided alternative and complementary solutions to those of an exclusively pharmaceutical chemical nature since scientists and clinicians invested in the optimization of materials and methods capable of regulating effective drug delivery at the nanometer scale. Among the many drug delivery carriers, lipid nano vesicular ones successfully support clinical candidates approaching such problems as insolubility, biodegradation, and difficulty in overcoming the skin and biological barriers such as the blood-brain one. In this review, the authors discussed the structure, the biochemical composition, and the drug delivery applications of lipid nanovesicular carriers, namely, niosomes, proniosomes, ethosomes, transferosomes, pharmacosomes, ufasomes, phytosomes, catanionic vesicles, and extracellular vesicles.

Antimicrobial Photodynamic Therapy: Latest Developments with a Focus on Combinatory Strategies

Antimicrobial photodynamic therapy (aPDT) has become a fundamental tool in modern therapeutics, notably due to the expanding versatility of photosensitizers (PSs) and the numerous possibilities to combine aPDT with other antimicrobial treatments to combat localized infections. After revisiting the basic principles of aPDT, this review first highlights the current state of the art of curative or preventive aPDT applications with relevant clinical trials. In addition, the most recent developments in photochemistry and photophysics as well as advanced carrier systems in the context of aPDT are provided, with a focus on the latest generations of efficient and versatile PSs and the progress towards hybrid-multicomponent systems. In particular, deeper insight into combinatory aPDT approaches is afforded, involving non-radiative or other light-based modalities. Selected aPDT perspectives are outlined, pointing out new strategies to target and treat microorganisms. Finally, the review works out the evolution of the conceptually simple PDT methodology towards a much more sophisticated, integrated, and innovative technology as an important element of potent antimicrobial strategies.