Development of a hybrid CuS-ICG polymeric photosensitive vector and its application in antibacterial photodynamic therapy.

At the present time, owing to the extremely high growth of microbial resistance to antibiotics and, consequently, the increased healthcare associated costs and the loss of efficacy of current treatments, the development of new therapies against bacteria is of paramount importance. For this reason, in this work, a hybrid synergetic nanovector has been developed, based on the encapsulation of a NIR (near infrared) photosensitive molecule (indocyanine green, ICG) in biodegradable polymeric nanoparticles (NPs). In addition, copper sulfide nanoparticles (CuS NPs), optically sensitive to NIR, were anchored on the polymeric nanoparticle shell in order to boost the generation of reactive oxygen species (ROS) upon NIR irradiation.

PLGA nanoparticle-encapsulated lysostaphin for the treatment of Staphylococcus aureus infections.

Staphylococcus aureus possesses the ability to become pathogenic, leading to severe and life-threatening infections. Its methicillin-resistant variant MRSA has garnered high-priority status due to its increased morbidity and associated mortality. This emphasizes the urgency for novel anti-staphylococcal agents.

Real-time in vivo monitoring of the antimicrobial action of combination therapies in the management of infected topical wounds.

The increasing prevalence of non-healing infected wounds has become a serious concern in the clinical practice, being associated to population aging and to the rising prevalence of several chronic conditions such as diabetes. Herein, the evaluation of the bactericidal and antibiofilm effects of the natural antiseptic terpenes thymol and farnesol standing alone or in combination with the standard care antiseptic chlorhexidine was carried out both in vitro and in vivo. The in vitro combinatorial treatment of chlorhexidine associated with those terpenes against Staphylococcus aureus in its planktonic and sessile forms demonstrated a superior antibacterial activity than that of chlorhexidine alone.

Antibody-Functionalized Polymer Nanoparticles for Targeted Antibiotic Delivery in Models of Pathogenic Bacteria Infecting Human Macrophages.

The efficacy of antibody-functionalized poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs), prepared by nanoprecipitation, carrying rifampicin (RIF) against planktonic, sessile, and intracellular and is reported here. A biotinylated anti- polyclonal antibody, which binds to structural antigens of the whole bacterium, was functionalized on the surface of RIF-loaded PLGA-based NPs by using the high-affinity avidin-biotin complex. This general strategy allows the binding of commercially available biotinylated antibodies.

X-ray Photoelectron Spectroscopy (XPS) Analysis of Nitrogen Environment in Small Extracellular Vesicle Membranes: A Potential Novel Technique with Application for Cancer Screening.

Small extracellular vesicle (EV) membranes display characteristic protein-lipidic composition features that are related to their cell of origin, providing valuable clues regarding their parental cell composition and real-time state. This could be especially interesting in the case of cancer cell-derived EVs, as their membranes could serve as valuable tools in liquid biopsy applications and to detect changes in the tumor malignancy. X-Ray Photoelectron Spectroscopy (XPS) is a powerful surface analysis technique able to detect every chemical element present, being also sensitive to their chemical environment.

Elucidating the mechanisms of action of antibiotic-like ionic gold and biogenic gold nanoparticles against bacteria.

The antimicrobial action of gold depends on different factors including its oxidation state in the intra- and extracellular medium, the redox potential, its ability to produce reactive oxygen species (ROS), the medium components, the properties of the targeted bacteria wall, its penetration in the bacterial cytosol, the cell membrane potential, and its interaction with intracellular components. We demonstrate that different gold species are able to induce bacterial wall damage as a result of their electrostatic interaction with the cell membrane, the promotion of ROS generation, and the consequent DNA damage. In-depth genomic and proteomic studies on Escherichia coli confirmed the superior toxicity of Au (III) vs Au (I) based on the different molecular mechanisms analyzed including oxidative stress, bacterial energetic metabolism, biosynthetic processes, and cell transport.

Evaluation of Fatigue Life of Recycled Opaque PET from Household Milk Bottle Wastes.

Polyethylene terephthalate (PET) is among the most used thermoplastic polymers in large scale manufacturing. Opaque PET is increasingly used in milk bottles to save weight and to bring a glossy white aspect due to TiO nanoparticles. The recyclability of opaque PET is an issue: whereas the recycling channels are well established for transparent PET, the presence of opaque PET in household wastes weakens those channels: opaque bottles cannot be mixed with transparent ones because the resulting blend is not transparent anymore.

Pharmacokinetic control on the release of antimicrobial drugs from pH-responsive electrospun wound dressings.

The acidic pH of healthy skin changes during wound healing due to the exposure of the inner dermal and subcutaneous tissue and due to the potential colonization of pathogenic bacteria. In chronic non-healing wounds, the pH values vary in a wide pH range but the appearance of an alkaline shift is common. After a wound is incurred, neutral pH in the wound bed is characteristic of the activation of the cascade of regenerative and remodeling processes.

Submicronic Filtering Media Based on Electrospun Recycled PET Nanofibers: Development, Characterization, and Method to Manufacture Surgical Masks.

The disposal of single-use personal protective equipment has brought a notable environmental impact in the context of the COVID-19 pandemic. During these last two years, part of the global research efforts has been focused on preventing contagion using nanotechnology. This work explores the production of filter materials with electrohydrodynamic techniques using recycled polyethylene terephthalate (PET).

Glutathione-Triggered catalytic response of Copper-Iron mixed oxide Nanoparticles. Leveraging tumor microenvironment conditions for chemodynamic therapy.

Heterogeneous catalysis has emerged as a promising alternative for the development of new cancer therapies. In addition, regarding the tumor microenvironment as a reactor with very specific chemical features has provided a new perspective in the search for catalytic nanoarchitectures with specific action against chemical species playing a key role in tumor metabolism. One of these species is glutathione (GSH), whose depletion is the cornerstone of emerging strategies in oncology, since this metabolite plays a pivotal regulatory role as antioxidant agent, dampening the harmful effects of intracellular reactive oxidative species (ROS).

Light activated pulsatile drug delivery for prolonged peripheral nerve block.

Regional anesthesia is widely used in peripheral nerve block and in neuraxial anesthesia to reduce anesthetics systemic side effects and shorten recovery times. However, when applied as a single injection (e.g.

Gold-Platinum Nanoparticles with Core-Shell Configuration as Efficient Oxidase-like Nanosensors for Glutathione Detection.

Nanozymes, defined as nanomaterials that can mimic the catalytic activity of natural enzymes, have been widely used to develop analytical tools for biosensing. In this regard, the monitoring of glutathione (GSH), a key antioxidant biomolecule intervening in the regulation of the oxidative stress level of cells or related with Parkinson's or mitochondrial diseases can be of great interest from the biomedical point of view. In this work, we have synthetized a gold-platinum Au@Pt nanoparticle with core-shell configuration exhibiting a remarkable oxidase-like mimicking activity towards the substrates 3,3',5,5'-tetramethylbenzidine (TMB) and -phenylenediamine (OPD).

Structure and Properties of Reactively Extruded Opaque Post-Consumer Recycled PET.

The recyclability of opaque PET, which contains TiO nanoparticles, has not been as well-studied as that of transparent PET. The objective of this work is to recycle post-consumer opaque PET through reactive extrusion with Joncryl. The effect of the reactive extrusion process on the molecular structure and on the thermal/mechanical/rheological properties of recycling post-consumer opaque PET (r-PET) has been analyzed.

Selective point-of-care detection of pathogenic bacteria using sialic acid functionalized gold nanoparticles.

In resource-limited settings, fast and simple point-of-need tests should facilitate healthcare providers the identification of pathogens avoiding empirical suboptimal treatments with broad-spectrum antibiotics. A rapid optical whole cell bacterial biosensor has been here developed using sialic acid functionalized gold nanoparticles allowing the selective screening of Gram-positive Staphylococcus aureus ATCC 25923 and Methicillin Resistant Staphylococcus aureus (MRSA) USA300 and Gram-negative bacteria (Pseudomonas aeruginosa ATCC 15442) by selecting the appropriate dispersing media. Those bacteria were selected due to their common presence in wound bed tissue of chronic infected topical wounds.

Nanogels with High Loading of Anesthetic Nanocrystals for Extended Duration of Sciatic Nerve Block.

The development of thermoresponsive nanogels loaded with nanocrystals of the local anesthetic bupivacaine nanocrystals (BNCs) for prolonged peripheral nerve pain relief is reported here. BNCs were prepared using the antisolvent precipitation method from the hydrophobic form of bupivacaine (bupivacaine free base). The as-prepared BNCs were used stand-alone or encapsulated in temperature-responsive poly(ethylene glycol) methyl ether methacrylate (OEGMA)-based nanogels, resulting in bupivacaine NC-loaded nanogels (BNC-nanogels) of monodisperse size.

Preparation of Cu cluster catalysts by simultaneous cooling-microwave heating: application in radical cascade annulation.

One of the hallmarks of microwave irradiation is its selective heating mechanism. In the past 30 years, alternative designs of chemical reactors have been introduced, where the microwave (MW) absorber occupies a limited reactor volume but the surrounding environment is MW transparent. This advantage results in a different heating profile or even the possibility to quickly cool down the system.

Antimicrobial Wound Dressings against Fluorescent and Methicillin-Sensitive Intracellular Pathogenic Bacteria.

There is limited evidence indicating that drug-eluting dressings are clinically more effective than simple conventional dressings. To shed light on this concern, we have performed evidence-based research to evaluate the antimicrobial action of thymol (THY)-loaded antimicrobial dressings having antibiofilm forming ability, able to eradicate intracellular and extracellular pathogenic bacteria. We have used four different strains, including the ATCC 25923 strain, the Newman strain (methicillin-sensitive strain, MSSA) expressing the coral green fluorescent protein from the vector pCN47, and two clinical reference strains, Newman-(MSSA) and USA300-(methicillin-resistant strain), as traceable models of pathogenic bacteria commonly infecting skin and soft tissues.

Controlling Particle Size and Release Kinetics in the Sustained Delivery of Oral Antibiotics Using pH-Independent Mucoadhesive Polymers.

Copolymers synthesized from acrylic acid and methacrylic acid used as gastroprotective and mucoadhesive enteric coatings have been used to prepare micro- (∼2 μm), submicro- (∼200 nm), and nanoparticles (∼20 nm) containing rifampicin (Rif) to obtain time-controlled drug release kinetics. Different particle sizes and drug release kinetics have been obtained using different synthesis conditions and fabrication techniques including the use of an electrosprayer and an interdigital microfabricated micromixer. The antimicrobial action of the encapsulated Rif has been demonstrated against ATCC 25923 and compared with the effect of the equivalent dose of the free macrolide antibiotic.

Potential Implantable Nanofibrous Biomaterials Combined with Stem Cells for Subchondral Bone Regeneration.

The treatment of osteochondral defects remains a challenge. Four scaffolds were produced using Food and Drug Administration (FDA)-approved polymers to investigate their therapeutic potential for the regeneration of the osteochondral unit. Polycaprolactone (PCL) and poly(vinyl-pyrrolidone) (PVP) scaffolds were made by electrohydrodynamic techniques.

Microflow Nanoprecipitation of Positively Charged Gastroresistant Polymer Nanoparticles of Eudragit RS100: A Study of Fluid Dynamics and Chemical Parameters.

The objective of the present work was to produce gastroresistant Eudragit RS100 nanoparticles by a reproducible synthesis approach that ensured mono-disperse nanoparticles under the size of 100 nm. Batch and micromixing nanoprecipitation approaches were selected to produce the demanded nanoparticles, identifying the critical parameters affecting the synthesis process. To shed some light on the formulation of the targeted nanoparticles, the effects of particle size and homogeneity of fluid dynamics, and physicochemical parameters such as polymer concentration, type of solvent, ratio of solvent to antisolvent, and total flow rate were studied.

Drug-eluting wound dressings having sustained release of antimicrobial compounds.

Wound healing is a complex and costly public health problem that should be timely addressed to achieve a rapid and adequate tissue repair avoiding or even eliminating potential pathogenic infection. Chronic infected non-healing wounds represent a serious concern for health care systems. Efficient wound dressings with tailored therapy having the best response and highest safety margin for the management of chronic non-healing wounds are still needed.

Efficiency of Antimicrobial Electrospun Thymol-Loaded Polycaprolactone Mats In Vivo.

Due to the prevalence of antimicrobial resistant pathogens, natural products with long-term antimicrobial activities are considered as potential alternatives. In this work, polycaprolactone (PCL) electrospun fibers with mean diameters around 299 nm and loaded with 14.92 ± 1.

Antibacterial Effect of Thymol Loaded SBA-15 Nanorods Incorporated in PCL Electrospun Fibers.

For the effective management of infected chronic wounds, the incorporation of antimicrobial drugs into wound dressings can increase their local availability at the infection site. Mesoporous silicon dioxide SBA-15 is an excellent drug carrier with tunable drug release kinetics. In this work, synthesized SBA-15 loaded with the natural antimicrobial compound thymol (THY) was incorporated into polycaprolactone (PCL) electrospun nanofibers to obtain an advanced wound dressing.

Electrospun anti-inflammatory patch loaded with essential oils for wound healing.

Wound healing is a complex process that consists of three overlapping phases: inflammation, proliferation, and remodeling. A bacterial infection can increase inflammation and delay this process. Microorganisms are closely related to the innate immune system, such as macrophages and neutrophils, as they can start an inflammatory cascade.

Antimicrobial Electrospun Polycaprolactone-Based Wound Dressings: An Study About the Importance of the Direct Contact to Elicit Bactericidal Activity.

To prepare efficient antibacterial carvacrol (CAR) and thymol (THY)-loaded electrospun polycaprolactone (PCL)-based wound dressings. Using electrospinning we were able to prepare wound dressings with antimicrobial action thanks to their large surface per volume ratio, which allows their loading with therapeutic amounts of active principles. By nuclear magnetic resonance we demonstrated that the antimicrobial compounds are donors of hydrogen bonds to the ester functional group in PCL, which acts as acceptor and that intermolecular interaction is responsible for the high drug loading achieved.