Extracellular Vesicles-Mediated Bio-Orthogonal Catalysis in Growing Tumors

Several studies have reported the successful use of bio-orthogonal catalyst nanoparticles (NPs) for cancer therapy. However, the delivery of the catalysts to the target tissues in vivo remains an unsolved challenge. The combination of catalytic NPs with extracellular vesicles (EVs) has been proposed as a promising approach to improve the delivery of therapeutic nanomaterials to the desired organs. In this study, we have developed a nanoscale bio-hybrid vector using a CO-mediated reduction at low temperature to generate ultrathin catalytic Pd nanosheets (PdNSs) as catalysts directly inside cancer-derived EVs. We have also compared their biodistribution with that of PEGylated PdNSs delivered by the EPR effect. Our results indicate that the accumulation of PdNSs in the tumour tissue was significantly higher when they were administered within the EVs compared to the PEGylated PdNSs. Conversely, the amount of Pd found in non-target organs (i.e., liver) was lowered. Once the Pd-based catalytic EVs were accumulated in the tumours, they enabled the activation of a paclitaxel prodrug demonstrating their ability to carry out bio-orthogonal uncaging chemistries in vivo for cancer therapy.

Thioredoxin domain containing 5 is involved in the hepatic storage of squalene into lipid droplets in a sex-specific way

Hepatic thioredoxin domain-containing 5 (TXNDC5) is a member of the protein disulfide isomerase family found associated with anti-steatotic properties of squalene and located in the endoplasmic reticulum and in lipid droplets. Considering that the latter are involved in hepatic squalene accumulation, the present research was aimed to investigate the role of TXNDC5 on hepatic squalene management in mice and in the AML12 hepatic cell line. Wild-type and TXNDC5-deficient (KO) mice were fed Western diets with or without 1% squalene supplementation for 6 weeks. In males, but not in females, absence of TXNDC5 blocked hepatic, but not duodenal, squalene accumulation. Hepatic lipid droplets were isolated and characterized using label-free LC-MS/MS analysis. TXNDC5 accumulated in this subcellular compartment of mice receiving squalene and was absent in TXNDC5-KO male mice. The latter mice were unable to store squalene in lipid droplets. CALR and APMAP were some of the proteins that responded to the squalene administration in all studied conditions. CALR and APMAP were positively associated with lipid droplets in the presence of squalene and they were decreased by the absence of TXNDC5. The increased squalene content was reproduced in vitro using AML12 cells incubated with squalene-loaded nanoparticles and this effect was not observed in an engineered cell line lacking TXNDC5. The phenomenon was also present when incubated in the presence of a squalene epoxidase inhibitor, suggesting a mechanism of squalene exocytosis involving CALR and APMAP. In conclusion, squalene accumulation in hepatic lipid droplets is sex-dependent on TXNDC5 that blocks its secretion.

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. Real-time in vivo monitoring of infection progression and antimicrobial treatment outcomes were evaluated using the bioluminescent S. aureus strain Xen36. In vivo studies on infected wound splinting murine models corroborated the superior bactericidal effects of the combinatorial treatments here proposed. Moreover, the encapsulation of thymol in electrospun Eudragit® S100 (i.e., a synthetic anionic copolymer of methacrylic acid and ethyl acrylate)-based wound dressings was also carried out in order to design efficient antimicrobial wound dressings.

Magnetite Mineralization inside Cross-Linked Protein Crystals

Crystallization in confined spaces is a widespread process in nature that also has important implications for the stability and durability of many man-made materials. It has been reported that confinement can alter essential crystallization events, such as nucleation and growth and, thus, have an impact on crystal size, polymorphism, morphology, and stability. Therefore, the study of nucleation in confined spaces can help us understand similar events that occur in nature, such as biomineralization, design new methods to control crystallization, and expand our knowledge in the field of crystallography. Although the fundamental interest is clear, basic models at the laboratory scale are scarce mainly due to the difficulty in obtaining well-defined confined spaces allowing a simultaneous study of the mineralization process outside and inside the cavities. Herein, we have studied magnetite precipitation in the channels of cross-linked protein crystals (CLPCs) with different channel pore sizes, as a model of crystallization in confined spaces. Our results show that nucleation of an Fe-rich phase occurs inside the protein channels in all cases, but, by a combination of chemical and physical effects, the channel diameter of CLPCs exerted a precise control on the size and stability of those Fe-rich nanoparticles. The small diameters of protein channels restrain the growth of metastable intermediates to around 2 nm and stabilize them over time. At larger pore diameters, recrystallization of the Fe-rich precursors into more stable phases was observed. This study highlights the impact that crystallization in confined spaces can have on the physicochemical properties of the resulting crystals and shows that CLPCs can be interesting substrates to study this process.

Iron inactivation by Sporobolomyces ruberrimus and its potential role in plant metal stress protection. An in vitro study

The endophytic Basidiomycete Sporobolomyces ruberrimus protects its host Arabidopsis arenosa against metal toxicity. Plants inoculated with the fungus yielded more biomass and exhibited significantly fewer stress symptoms in medium mimicking mine dump conditions (medium supplemented with excess of Fe, Zn and Cd). Aside from fine-tuning plant metal homeostasis, the fungus was capable of precipitating Fe in the medium, most likely limiting host exposure to metal toxicity. The precipitated residue was identified by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-Ray Diffraction (XRD) and electron microscopy (SEM/TEM) with energy dispersive X-Ray analysis (EDX/SAED) techniques. The performed analyses revealed that the fungus transforms iron into amorphous (oxy)hydroxides and phosphates and immobilizes them in the form of a precipitate changing Fe behaviour in the MSR medium. Moreover, the complexation of free Fe ions by fungi could be obtained by biomolecules such as lipids, proteins, or biosynthesized redox-active molecules.

Colistin-loaded aerosolizable particles for the treatment of bacterial respiratory infections

Compared to parenteral administration of colistin, its direct pulmonary administration can maximize lung drug deposition while reducing systemic adverse side effects and derived nephrotoxicity. Current pulmonary administration of colistin is carried out by the aerosolization of a prodrug, colistin methanesulfonate (CMS), which must be hydrolized to colistin in the lung to produce its bactericidal effect. However, this conversion is slow relative to the rate of absorption of CMS, and thus only 1.4 % (w/w) of the CMS dose is converted to colistin in the lungs of patients receiving inhaled CMS. We synthesized several aerosolizable nanoparticle carriers loaded with colistin using different techniques and selected particles with sufficient drug loading and adequate aerodynamic behavior to efficiently deliver colistin to the entire lung. Specifically, we carried out (i) the encapsulation of colistin by single emulsion-solvent evaporation with immiscible solvents using polylactic-co-glycolic (PLGA) nanoparticles; (ii) its encapsulation using nanoprecipitation with miscible solvents using poly(lactide-co-glycolide)-block-poly(ethylene glycol) as encapsulating matrix; (iii) colistin nanoprecipitation using the antisolvent precipitation method and its subsequent encapsulation within PLGA nanoparticles; and (iv) colistin encapsulation within PLGA-based microparticles using electrospraying. Nanoprecipitation of pure colistin using antisolvent precipitation showed the highest drug loading (55.0 ± 4.8 wt%) and spontaneously formed aggregates with adequate aerodynamic diameter (between 3 and 5 μm) to potentially reach the entire lung. These nanoparticles were able to completely eradicate Pseudomonas aeruginosa in an in vitro lung biofilm model at 10 µg/mL (MBC). This formulation could be a promising alternative for the treatment of pulmonary infections improving lung deposition and, therefore, the efficacy of aerosolized antibiotics.

Superfluorinated Extracellular Vesicles for In Vivo Imaging by 19F-MRI

Extracellular vesicles (EVs) play a crucial role in cell-to-cell communication and have great potential as efficient delivery vectors. However, a better understanding of EV in vivo behavior is hampered by the limitations of current imaging tools. In addition, chemical labels present the risk of altering the EV membrane features and, thus, in vivo behavior. 19F-MRI is a safe bioimaging technique providing selective images of exogenous probes. Here, we present the first example of fluorinated EVs containing PERFECTA, a branched molecule with 36 magnetically equivalent 19F atoms. A PERFECTA emulsion is given to the cells, and PERFECTA-containing EVs are naturally produced. PERFECTA-EVs maintain the physicochemical features, morphology, and biological fingerprint as native EVs but exhibit an intense 19F-NMR signal and excellent 19F relaxation times. In vivo 19F-MRI and tumor-targeting capabilities of stem cell-derived PERFECTA-EVs are also proved. We propose PERFECTA-EVs as promising biohybrids for imaging biodistribution and delivery of EVs throughout the body.

In Cellulo Bioorthogonal Catalysis by Encapsulated Nanoalloys: Overcoming Intracellular Deactivation

Bioorthogonal metallocatalysis has opened up a xenobiotic route to perform nonenzymatic catalytic transformations in living settings. Despite their promising features, most metals are deactivated inside cells by a myriad of reactive biomolecules, including biogenic thiols, thereby limiting the catalytic functioning of these abiotic reagents. Here we report the development of cytocompatible alloyed AuPd nanoparticles with the capacity to elicit bioorthogonal depropargylations with high efficiency in biological media. We also show that the intracellular catalytic performance of these nanoalloys is significantly enhanced by protecting them following two different encapsulation methods. Encapsulation in mesoporous silica nanorods resulted in augmented catalyst reactivity, whereas the use of a biodegradable PLGA matrix increased nanoalloy delivery across the cell membrane. The functional potential of encapsulated AuPd was demonstrated by releasing the potent chemotherapy drug paclitaxel inside cancer cells. Nanoalloy encapsulation provides a novel methodology to develop nanoreactors capable of mediating new-to-life reactions in cells.

Toward continuous production of high-quality nanomaterials using microfluidics: nanoengineering the shape, structure and chemical composition

Over the last decade, a multitude of synthesis strategies has been reported for the production of high-quality nanoparticles. Wet-chemical methods are generally the most efficient synthesis procedures since high control of crystallinity and physicochemical properties can be achieved. However, a number of challenges remain from inadequate reaction control during the nanocrystallization process; specifically variability, selectivity, scalability and safety. These shortcomings complicate the synthesis, make it difficult to obtain a uniform product with desired properties, and present serious limitations for scaling the production of colloidal nanocrystals from academic studies to industrial applications. Continuous flow reactors based on microfluidic principles offer potential solutions and advantages. The reproducibility of reaction conditions in microfluidics and therefore product quality have proved to exceed those obtained by batch processing. Considering that in nanoparticles' production not only is it crucial to control the particle size distribution, but also the shape and chemical composition, this review presents an overview of the current state-of-the-art in synthesis of anisotropic and faceted nanostructures by using microfluidics techniques. The review surveys the available tools that enable shape and chemical control, including secondary growth methods, active segmented flow, and photoinduced shape conversion. In addition, emphasis is placed on the available approaches developed to tune the structure and chemical composition of nanomaterials in order to produce complex heterostructures in a continuous and reproducible fashion.

Squalene Loaded Nanoparticles Effectively Protect Hepatic AML12 Cell Lines against Oxidative and Endoplasmic Reticulum Stress in a TXNDC5-Dependent Way

Virgin olive oil, the main source of fat in the Mediterranean diet, contains a substantial amount of squalene which possesses natural antioxidant properties. Due to its highly hydrophobic nature, its bioavailability is reduced. In order to increase its delivery and potentiate its actions, squalene has been loaded into PLGA nanoparticles (NPs). The characterization of the resulting nanoparticles was assessed by electron microscopy, dynamic light scattering, zeta potential and high-performance liquid chromatography. Reactive oxygen species (ROS) generation and cell viability assays were carried out in AML12 (alpha mouse liver cell line) and a TXNDC5-deficient AML12 cell line (KO), which was generated by CRISPR/cas9 technology. According to the results, squalene was successfully encapsulated in PLGA NPs, and had rapid and efficient cellular uptake at 30 µM squalene concentration. Squalene reduced ROS in AML12, whereas ROS levels increased in KO cells and improved cell viability in both when subjected to oxidative stress by significant induction of Gpx4. Squalene enhanced cell viability in ER-induced stress by decreasing Ern1 or Eif2ak3 expressions. In conclusion, TXNDC5 shows a crucial role in regulating ER-induced stress through different signaling pathways, and squalene protects mouse hepatocytes from oxidative and endoplasmic reticulum stresses by several molecular mechanisms depending on TXNDC5.

Hybrid thermoresponsive nanoparticles containing drug nanocrystals for NIR-triggered remote release

The on-demand administration of anaesthetic drugs can be a promising alternative for chronic pain management. To further improve the efficacy of drug delivery vectors, high drug loadings combined with a spatiotemporal control on the release can not only relief the pain according to patient's needs, but also improve the drawbacks of conventional burst release delivery systems. In this study, a hybrid nanomaterial was developed by loading bupivacaine nanocrystals (BNCs) into oligo(ethylene glycol) methyl ether methacrylate (OEGMA)-based thermoresponsive nanogels and coupling them to NIR-absorbing biodegradable copper sulphide nanoparticles (CuS NPs). Those CuS NPs were surface modified with polyelectrolytes using layer-by-layer techniques to be efficiently attached to the surface of nanogels by means of supramolecular interactions. The encapsulation of bupivacaine in the form of nanocrystals allowed to achieve CuS@BNC-nanogels having drug loadings as high as 65.5 wt%. The nanocrystals acted as long-lasting drug reservoirs, leading to an elevated localized drug content, which was useful for their application in prolonged pain relief. The CuS@BNC-nanogels exhibited favorable photothermal transducing properties upon NIR-light irradiation. The photothermal effect granted by the CuS NPs triggered the nano-crystallized drug release to be boosted by the collapse of the thermoresponsive nanogels upon heating. Remote control was achieved for on-demand release at a specific time and place, indicating their potential use as an externally activated triggerable drug-delivery system. Furthermore, cell viability tests and flow cytometry analysis were performed showing satisfactory cytocompatibility in the dose-ranging study having a subcytotoxic concentration of 0.05 mg/mL for CuS@BNC-nanogels. This remotely activated nanoplatform is a promising strategy for long-lasting controlled analgesia and a potential alternative for clinical pain management.

Chalcogenide nanoparticles and organic photosensitizers for synergetic antimicrobial photodynamic therapy

Synergistic antimicrobial effects were observed for copper sulfide (CuS) nanoparticles together with indocyanine green (ICG) in the elimination of wild type pathogenic bacteria (Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 27853) and also opportunistic fungal infective yeast (Candida albicans ATCC 10231). Furthermore, large antibacterial effects were observed for clinical isolates of Methicillin-resistant S. aureus (MRSA) PFGE strain-type USA300. This efficient antimicrobial action was attributed to the combined extra- and intracellular generation of reactive oxygen species upon light irradiation. Instead of the use of visible-light for the activation of common photosensitizers, both ICG and CuS nanoparticles can be activated in the near infrared (NIR)-region of the electromagnetic spectrum and therefore, superior tissue penetration would be expected in a potential elimination of pathogenic microorganisms not only on the skin but also in the soft tissue. In the different bacteria studied a 3-log reduction in the bacterial counts was achieved after only 6 min of NIR irradiation and treatment with ICG or CuS alone at concentrations of 40 and 160 µg mL^-1, respectively. A maximum bactericidal effect against S. aureus and USA300 strains was obtained for the combination of both photosensitizers at the same concentration. Regarding P. aeruginosa, a 4-log reduction in the CFU was observed for the combination of CuS and ICG at various concentrations. In Candida albicans the combination of both ICG and CuS and light irradiation showed an antimicrobial dose-dependent effect with the reduction of at least 3-log in the cell counts for the combination of ICG + CuS at reduced concentrations. The observed antimicrobial effect was solely attributed to a photodynamic effect and any photothermal effect was avoided to discard any potential thermal injury in a potential clinical application. The generation of reactive oxygen species upon near infrared-light irradiation for those photosensitizers used was measured either alone or in combination. The cytocompatibility of the proposed materials at the doses used in photodynamic therapy was also demonstrated in human dermal fibroblasts and keratinocytes by cell culturing and flow cytometry studies.

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. The discrimination of bacterial pathogens has been attempted in different media including water, two independent buffers, bacterial broth, human serum and human urine. The identification of Gram + bacterial pathogens was also assessed under simultaneous co-culture of S. Aureus and Pseudomonas aeruginosa. High bacterial loads were required to provide with a statistically significant optical pathogen identification in human serum whereas it was not possible to detect the presence of bacteria at clinically relevant levels in urine.

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. The synthesis protocol has rendered high drug loadings (i.e., 93.8 ± 1.5 and 84.8 ± 1.2 wt % for the NC and BNC-nanogels, respectively) and fast drug dissolution kinetics in the resulting composite material. In vivo tests demonstrated the efficacy of the formulation along with an extended duration of sciatic nerve block in murine models of more than 8 h with a formulation containing only 2 mg of the local anesthetic thanks to the thermoresponsive character of the polymer, which, at body temperature, becomes hydrophobic and acts as a diffusion barrier for the encapsulated drug nanocrystals. The hydrophobicity of the encapsulated bupivacaine free base probably facilitates its pass through cell membranes and also binds strongly to their hydrophobic lipid bilayer, thereby protecting molecules from diffusion to extracellular media and to the bloodstream, reducing their clearance. When using BNC-nanogels, the duration of the anesthetic blockage lasted twice as long as compared to the effect of just BNCs or a conventional bupivacaine hydrochloride solution both containing equivalent amounts of the free drug. Results of the in vivo tests showed enough sensory nerve block to potentially relieve pain, but still having mobility in the limb, which enables motor function when required. The BNC-nanogels presented minimal toxicity in the in vivo study due to their sustained drug release and excellent biocompatibility. The encapsulation of nano-sized crystals of bupivacaine provides a prolonged regional anesthesia with reduced toxicity, which could be advantageous in the management of chronic pain.

Continuous selective deoxygenation of palm oil for renewable diesel production over Ni catalysts supported on Al2O3 and La2O3-Al2O3

The present study provides, for the first time in the literature, a comparative assessment of the catalytic performance of Ni catalysts supported on γ-Al₂O₃ and γ-Al₂O₃ modified with La₂O₃, in a continuous flow trickle bed reactor, for the selective deoxygenation of palm oil. The catalysts were prepared via the wet impregnation method and were characterized, after calcination and/or reduction, by N₂ adsorption/desorption, XRD, NH₃-TPD, CO₂-TPD, H₂-TPR, H₂-TPD, XPS and TEM, and after the time-on-stream tests, by TGA, TPO, Raman and TEM. Catalytic experiments were performed between 300–400 °C, at a constant pressure (30 bar) and different LHSV (1.2–3.6 h⁻¹). The results show that the incorporation of La₂O₃ in the Al₂O₃ support increased the Ni surface atomic concentration (XPS), affected the nature and abundance of surface basicity (CO₂-TPD), and despite leading to a drop in surface acidity (NH₃-TPD), the Ni/LaAl catalyst presented a larger population of medium-strength acid sites. These characteristics helped promote the SDO process and prevented extended cracking and the formation of coke. Thus, higher triglyceride conversions and n-C₁₅ to n-C₁₈ hydrocarbon yields were achieved with the Ni/LaAl at lower reaction temperatures. Moreover, the Ni/LaAl catalyst was considerably more stable during 20 h of time-on-stream. Examination of the spent catalysts revealed that both carbon deposition and degree of graphitization of the surface coke, as well as, the extent of sintering were lower on the Ni/LaAl catalyst, explaining its excellent performance during time-on-stream.

Highly selective and stable Ni supported on La₂O₃–Al₂O₃ catalyst on the deCO/deCO₂ reaction paths for the production of renewable diesel.

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. Simultaneous cooling-microwave heating has been largely adopted for organic chemical transformations. However, to the best of our knowledge there are no reports of its application in the field of nanocluster synthesis. In this work, we propose an innovative one-pot procedure for the synthesis of Cu nanoclusters. The cluster nucleation was selectively MW-activated inside the pores of a highly ordered mesoporous substrate. Once the nucleation event occurred, the crystallization reaction was instantaneously quenched, precluding the growth events and favoring the production of Cu clusters with a homogenous size distribution. Herein, we demonstrated that Cu nanoclusters could be successfully adopted for radical cascade annulations of N-alkoxybenzamides, resulting in various tricyclic and tetracyclic isoquinolones, which are widely present in lots of natural products and bioactive compounds. Compared to reported homogeneous methods, supported Cu nanoclusters provide a better platform for a green, sustainable and efficient heterogeneous approach for the synthesis of tricyclic and tetracyclic isoquinolones, avoiding a variety of toxic waste/byproducts and metal contamination in the final products.

Key Population Hotspots in Nigeria for Targeted HIV Program Planning: Mapping, Validation, and Reconciliation

Background

With the fourth highest HIV burden globally, Nigeria is characterized as having a mixed HIV epidemic with high HIV prevalence among key populations, including female sex workers, men who have sex with men, and people who inject drugs. Reliable and accurate mapping of key population hotspots is necessary for strategic placement of services and allocation of limited resources for targeted interventions.

Objective

We aimed to map and develop a profile for the hotspots of female sex workers, men who have sex with men, and people who inject drugs in 7 states of Nigeria to inform HIV prevention and service programs and in preparation for a multiple-source capture-recapture population size estimation effort.

Methods

In August 2018, 261 trained data collectors from 36 key population–led community-based organizations mapped, validated, and profiled hotspots identified during the formative assessment in 7 priority states in Nigeria designated by the United States President’s Emergency Plan for AIDS Relief. Hotspots were defined as physical venues wherein key population members frequent to socialize, seek clients, or engage in key population–defining behaviors. Hotspots were visited by data collectors, and each hotspot’s name, local government area, address, type, geographic coordinates, peak times of activity, and estimated number of key population members was recorded. The number of key population hotspots per local government area was tabulated from the final list of hotspots.

Results

A total of 13,899 key population hotspots were identified and mapped in the 7 states, that is, 1297 in Akwa Ibom, 1714 in Benue, 2666 in Cross River, 2974 in Lagos, 1550 in Nasarawa, 2494 in Rivers, and 1204 in Federal Capital Territory. The most common hotspots were those frequented by female sex workers (9593/13,899, 69.0%), followed by people who inject drugs (2729/13,899, 19.6%) and men who have sex with men (1577/13,899, 11.3%). Although hotspots were identified in all local government areas visited, more hotspots were found in metropolitan local government areas and state capitals.

Conclusions

The number of key population hotspots identified in this study is more than that previously reported in similar studies in Nigeria. Close collaboration with key population–led community-based organizations facilitated identification of many new and previously undocumented key population hotspots in the 7 states. The smaller number of hotspots of men who have sex with men than that of female sex workers and that of people who inject drugs may reflect the social pressure and stigma faced by this population since the enforcement of the 2014 Same Sex Marriage (Prohibition) Act, which prohibits engaging in intimate same-sex relationships, organizing meetings of gays, or patronizing gay businesses.

Nondestructive production of exosomes loaded with ultrathin palladium nanosheets for targeted bio-orthogonal catalysis

The use of exosomes as selective delivery vehicles of therapeutic agents, such as drugs or hyperthermia-capable nanoparticles, is being intensely investigated on account of their preferential tropism toward their parental cells. However, the methods used to introduce a therapeutic load inside exosomes often involve disruption of their membrane, which may jeopardize their targeting capabilities, attributed to their surface integrins. On the other hand, in recent years bio-orthogonal catalysis has emerged as a new tool with a myriad of potential applications in medicine. These bio-orthogonal processes, often based on Pd-catalyzed chemistry, would benefit from systems capable of delivering the catalyst to target cells. It is therefore highly attractive to combine the targeting capabilities of exosomes and the bio-orthogonal potential of Pd nanoparticles to create new therapeutic vectors. In this protocol, we provide detailed information on an efficient procedure to achieve a high load of catalytically active Pd nanosheets inside exosomes, without disrupting their membranes. The protocol involves a multistage process in which exosomes are first harvested, subjected to impregnation with a Pd salt precursor followed by a mild reduction process using gas-phase CO, which acts as both a reducing and growth-directing agent to produce the desired nanosheets. The technology is scalable, and the protocol can be conducted by any researcher having basic biology and chemistry skills in ~3 d.

Towards plant-mediated chemistry - Au nanoparticles obtained using aqueous extract of Rosa damascena and their biological activity in vitro

An eco-friendly, efficient, and controlled synthesis of gold nanoparticles with application of the aqueous extract of Rosa damascena (Au@RD NPs) without using any other reducing agents was studied. Au@RD NPs of narrow size distribution were characterized by UV-vis and FT-IR spectroscopies, transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, particle size analysis, and zeta potential measurements. In vitro stability experiments revealed that the Au@RD NPs were stable for over a year (pH ~ 3.5), proving a significant stabilizing potential of the aqueous RD extract. The high total content of polyphenols, flavonoids, and reducing sugars along with the powerful antioxidant activity of the RD extract was determined by spectroscopic and analytical methods. Colloids prepared from the purified and lyophilized Au@RD NPs (electrokinetic potential of ca. -33 mV) were stable for at least 24 h under terms similar to physiological conditions (pH = 7.4, PBS). The in vitro cytotoxicity of Au@RD NPs was investigated against peripheral blood mononuclear lymphocytes (PBML), acute promyelocytic leukemia (HL60), and human lung adenocarcinoma (A549). Selective cytotoxicity of Au@RD NPs towards cancer cells (HL60, A549) over normal cells (PBML) in vitro was explicitly demonstrated by viability assays. Comet assay revealed a higher level of DNA damages in cancer cells when compared with normal ones. Apoptotic death in cancer cells was proved by measuring caspases activity. Thus, the developed Au@RD NPs, obtained by the plant-mediated green synthesis, are attractive hybrid materials for the medical applications combining two active components - metal nanoparticles platform and plant-derived metabolites.

Continuous Single-Phase Synthesis of [Au25(Cys)18] Nanoclusters and their Photobactericidal Enhancement

Thiolate-gold nanoclusters have various applications. However, most of the synthesis methods require prolonged synthesis times from several hours to days. In the present study, we report a rapid synthesis method for [Au₂₅(Cys)₁₈] nanoclusters and their application for photobactericidal enhancement. For [Au₂₅(Cys)₁₈] synthesis, we employed a tube-in-tube membrane reactor using CO as a reducing agent at elevated temperatures. This approach allows continuous generation of high-quality [Au₂₅(Cys)₁₈] within 3 min. Photobactericidal tests against Staphylococcus aureus showed that crystal violet-treated polymer did not have photobactericidal activity, but addition of [Au₂₅(Cys)₁₈] in the treated polymer demonstrated a potent photobactericidal activity at a low white light flux, resulting in >4.29 log reduction in viable bacteria numbers. Steady-state and time-resolved photoluminescence spectroscopies demonstrated that after light irradiation, photoexcited electrons in crystal violet flowed to [Au₂₅(Cys)₁₈] in the silicone, suggesting that redox reaction from [Au₂₅(Cys)₁₈] enhanced the photobactericidal activity. Stability tests revealed that leaching of crystal violet and [Au₂₅(Cys)₁₈] from the treated silicone was negligible and cyclic testing showed that the silicone maintained a strong photobactericidal activity after repeated use.

Insights into the mechanism of the formation of noble metal nanoparticles by in situ NMR spectroscopy

High-resolution solution Nuclear Magnetic Resonance (NMR) spectroscopy has been used to gain insights into the mechanism of the formation of gold, platinum and gold-platinum alloyed nanoparticles using metal precursors and tetrakis(hydroxymethyl)phosphonium chloride (THPC) as starting materials. THPC is widely used in nanochemistry as a reductant and stabilizer of nanoparticles, however the identity of the species responsible for each role is unknown. The multinuclear study of the reaction media by NMR spectroscopy allowed us to elucidate the structure of all the compounds that participate in the transformation from the metal salt precursor to the reduced metal that forms the nanoparticle, thus clarifying the controversy found in the literature regarding the formation of THPC-based compounds. The progress of the reaction was monitored from the initial moments of the synthesis to the end of the reaction and after long periods of time. Insights into the dual role of THPC were gained, identifying methanol and hydrogen as the actual reducing agents, and tris(hydroxymethyl)phosphine oxide (THPO) as the real stabilizing agent. Finally, the different stabilities of gold and platinum nanoparticles can be attributed to the different catalytic activities of the metals.

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 Staphylococcus aureus ATCC 25923 and compared with the effect of the equivalent dose of the free macrolide antibiotic. At low concentrations, the encapsulated antibiotic showed superior antimicrobial activity than the free drug. The stability of the developed particles has been evaluated in vitro under simulated gastric and intestinal conditions. At the concentrations tested, a reduced cytotoxicity against different human cell lines was observed after analyzing their subcytotoxic doses and the influence on their cell cycle by flow cytometry. Drug release kinetics can be tuned by adjusting particle sizes, and it would be possible to reach the minimum inhibitory concentration or the minimum bactericidal concentration at different time points depending on the medical needs.

Triggered drug release from hybrid thermoresponsive nanoparticles using near infrared light

Aim: Developing hybrid poly(N-isopropylacrylamide)-based nanogels decorated with plasmonic hollow gold nanoparticles for on-demand drug delivery and their physico-chemical characterization, bupivacaine loading and release ability upon light irradiation, and in vitro cell viability. Materials & methods: Hollow gold nanoparticles were prepared by galvanic replacement reaction; poly(N-isopropylacrylamide)-based nanogels were synthesized via precipitation polymerization and their electrostatic coupling was accomplished using poly(allylamine hydrochloride) as cationic polyelectrolyte linker. Results & conclusion: Colloidal stability of the resulted hybrid nanovectors was demonstrated under physiological conditions together with their fast response and excellent heating efficiency after light stimulation, indicating their potential use as triggered drug-delivery vectors. Moreover, their influence on cell metabolism and cell cycle under subcytotoxic doses were studied showing excellent cytocompatibility.

Anticancer potency of novel organometallic Ir(iii) complexes with phosphine derivatives of fluoroquinolones encapsulated in polymeric micelles

A 3D model of cell culturing (spheroids) was explored and the anticancer potential of the selected novel organometallic Ir(iii) complex encapsulated in Pluronic p-123 micelles was clearly proved.

Gold nanoparticles for the in situ polymerization of near-infrared responsive hydrogels based on fibrin

Non-invasiveness and relative safety of photothermal therapy, which enables local hyperthermia of target tissues using a near infrared (NIR) laser, has attracted increasing interest. Due to their biocompatibility, amenability of synthesis and functionalization, gold nanoparticles have been investigated as therapeutic photothermal agents. In this work, hollow gold nanoparticles (HGNP) were coated with poly-l-lysine through the use of COOH-Poly(ethylene glycol)-SH as a covalent linker. The functionalized HGNP, which peak their surface plasmon resonance at 800 nm, can bind thrombin. Thrombin-conjugated HGNP conduct in situ fibrin polymerization, facilitating the process of generating photothermal matrices. Interestingly, the metallic core of thrombin-loaded HGNP fragmentates at physiological temperature. During polymerization process, matrices prepared with thrombin-loaded HGNP were loaded with genetically-modified stem cells that harbour a heat-activated and ligand-dependent gene switch for regulating transgene expression. NIR laser irradiation of resulting cell constructs in the presence of ligand successfully triggered transgene expression in vitro and in vivo. STATEMENT OF SIGNIFICANCE: Current technological development allows synthesis of gold nanoparticles (GNP) in a wide range of shapes and sizes, consistently and at scale. GNP, stable and easily functionalized, show low cytotoxicity and high biocompatibility. Allied to that, GNP present optoelectronic properties that have been exploited in a range of biomedical applications. Following a layer-by-layer functionalization approach, we prepared hollow GNP coated with a positively charged copolymer that enabled thrombin conjugation. The resulting nanomaterial efficiently catalyzed the formation of fibrin hydrogels which convert energy of the near infrared (NIR) into heat. The resulting NIR-responsive hydrogels can function as scaffolding for cells capable of controlled gene expression triggered by optical hyperthermia, thus allowing the deployment of therapeutic gene products in desired spatiotemporal frameworks.

Targeted Release of Probiotics from Enteric Microparticulated Formulations

The development of advanced probiotic delivery systems, which preserve bacteria from degradation of the gastrointestinal tract and achieve a targeted release mediated by pH-independent swelling, is of great interest to improve the efficient delivery of probiotic bacteria to the target tissue. Gram-positive and Gram-negative bacteria models (Lactobacillus acidophilus (Moro) Hansen and Mocquot (ATCC® 4356™) and Escherichia coli S17, respectively) have been successfully encapsulated for the first time in pH-independent microparticulate polymethacrylates (i.e., Eudraguard biotic) used for the targeted delivery of nutraceuticals to the colon. These bacteria have also been encapsulated within the mucoadhesive polymethacrylate Eudragit RS 100 widely used as targeted release formulation for active pharmaceutical ingredients. The enteric microparticles remained unaltered under simulated gastric conditions and released the contained viable microbial cargo under simulated intestinal conditions. Buoyancies of 90.2% and 57.3% for Eudragit and Eudraguard microparticles, respectively, and long-term stability (5 months) for the encapsulated microorganisms were found. Cytotoxicity of the microparticles formulated with both polymers was evaluated (0.5-20 mg/mL) on Caco-2 cells, showing high cytocompatibility. These results underline the suitability of the synthesized materials for the successful delivery of probiotic formulations to the target organ, highlighting for the first time the potential use of Eudraguard biotic as an effective enteric coating for the targeted delivery of probiotics.

Continuous Microfluidic Synthesis of Pd Nanocubes and PdPt Core-Shell Nanoparticles and Their Catalysis of NO2 Reduction

Faceted colloidal nanoparticles are currently of immense interest due to their unique electronic, optical, and catalytic properties. However, continuous flow synthesis that enables rapid formation of faceted nanoparticles of single or multi-elemental composition is not trivial. We present a continuous flow synthesis route for the synthesis of uniformly sized Pd nanocubes and PdPt core-shell nanoparticles in a single-phase microfluidic reactor, which enables rapid formation of shaped nanoparticles with a reaction time of 3 min. The PdPt core-shell nanoparticles feature a dendritic, high surface area with the Pt shell covering the Pd core, as verified using high-resolution scanning transmission electron microscopy and energy dispersive X-ray spectroscopy. The Pd nanocubes and PdPt core-shell particles are catalytically tested during NO₂ reduction in the presence of H₂ in a flow pocket reactor. The Pd nanocubes exhibited low-temperature activity (i.e., <136 °C) and poor selectivity performance toward production of N₂O or N₂, whereas PdPt core-shell nanoparticles showed higher activity and were found to achieve better selectivity during NO₂ reduction retaining its basic structure at relatively elevated temperatures, making the PdPt core-shell particles a unique, desirable synergic catalyst material for potential use in NO_x abatement processes.

Liver Expression of a MiniATP7B Gene Results in Long-Term Restoration of Copper Homeostasis in a Wilson Disease Model in Mice

Gene therapy with an adeno-associated vector (AAV) serotype 8 encoding the human ATPase copper-transporting beta polypeptide (ATP7B) complementary DNA (cDNA; AAV8-ATP7B) is able to provide long-term copper metabolism correction in 6-week-old male Wilson disease (WD) mice. However, the size of the genome (5.2 kilobases [kb]) surpasses the optimal packaging capacity of the vector, which resulted in low-yield production; in addition, further analyses in WD female mice and in animals with a more advanced disease revealed reduced therapeutic efficacy, as compared to younger males. To improve efficacy of the treatment, an optimized shorter AAV vector was generated, in which four out of six metal-binding domains (MBDs) were deleted from the ATP7B coding sequence, giving rise to the miniATP7B protein (Δ57-486-ATP7B). In contrast to AAV8-ATP7B, AAV8-miniATP7B could be produced at high titers and was able to restore copper homeostasis in 6- and 12-week-old male and female WD mice. In addition, a recently developed synthetic AAV vector, AAVAnc80, carrying the miniATP7B gene was similarly effective at preventing liver damage, restoring copper homeostasis, and improving survival 1 year after treatment. Transduction of approximately 20% of hepatocytes was sufficient to normalize copper homeostasis, suggesting that corrected hepatocytes are acting as a sink to eliminate excess of copper. Importantly, administration of AAVAnc80-miniATP7B was safe in healthy mice and did not result in copper deficiency. Conclusion: In summary, gene therapy using an optimized therapeutic cassette in different AAV systems provides long-term correction of copper metabolism regardless of sex or stage of disease in a clinically relevant WD mouse model. These results pave the way for the implementation of gene therapy in WD patients.

National health information systems for achieving the Sustainable Development Goals

OBJECTIVES

Achieving the Sustainable Development Goals will require data-driven public health action. There are limited publications on national health information systems that continuously generate health data. Given the need to develop these systems, we summarised their current status in low-income and middle-income countries.

SETTING

The survey team jointly developed a questionnaire covering policy, planning, legislation and organisation of case reporting, patient monitoring and civil registration and vital statistics (CRVS) systems. From January until May 2017, we administered the questionnaire to key informants in 51 Centers for Disease Control country offices. Countries were aggregated for descriptive analyses in Microsoft Excel.

RESULTS

Key informants in 15 countries responded to the questionnaire. Several key informants did not answer all questions, leading to different denominators across questions. The Ministry of Health coordinated case reporting, patient monitoring and CRVS systems in 93% (14/15), 93% (13/14) and 53% (8/15) of responding countries, respectively. Domestic financing supported case reporting, patient monitoring and CRVS systems in 86% (12/14), 75% (9/12) and 92% (11/12) of responding countries, respectively. The most common uses for system-generated data were to guide programme response in 100% (15/15) of countries for case reporting, to calculate service coverage in 92% (12/13) of countries for patient monitoring and to estimate the national burden of disease in 83% (10/12) of countries for CRVS. Systems with an electronic component were being used for case reporting, patient monitoring, birth registration and death registration in 87% (13/15), 92% (11/12), 77% (10/13) and 64% (7/11) of responding countries, respectively.

CONCLUSIONS

Most responding countries have a solid foundation for policy, planning, legislation and organisation of health information systems. Further evaluation is needed to assess the quality of data generated from systems. Periodic evaluations may be useful in monitoring progress in strengthening and harmonising these systems over time.

The in vivo effects of silver nanoparticles on terrestrial isopods, Porcellio scaber, depend on a dynamic interplay between shape, size and nanoparticle dissolution properties

The present work aims to study the effects that acute exposure to low concentrations of silver nanoparticles (AgNPs) cause in digestive glands of terrestrial isopods (Porcellio scaber). The experiments were designed to integrate different analytical techniques, such as transmission electron microscopy, atomic absorption spectroscopy, proton induced X-ray emission, and Fourier transform IR imaging (FTIRI), in order to gain a comprehensive insight into the process from the AgNPs' synthesis to their interaction with biological tissues in vivo. To this aim, terrestrial isopods were fed with AgNPs having different shapes, sizes, and concentrations. For all the tested conditions, no toxicity at the whole organism level was observed after 14 days of exposure. However, FTIRI showed that AgNPs caused detectable local changes in proteins, lipids, nucleic acids and carbohydrates at the tissue level, to an extent dependent on the interplay of the AgNPs' properties: shape, size, concentration and dissolution of ions from them.

Revealing the Formation Mechanism of Alloyed Pd-Ru Nanoparticles: A Conversion Measurement Approach Utilizing a Microflow Reactor

The synthesis of alloyed nanoparticles has been studied extensively; however, the formation mechanisms involved remain unclear. Here, we reveal the detailed formation mechanism of alloyed nanoparticles in a Pd-Ru system, using a semibatch polyol method in which the simultaneous rapid reduction of both precursors was assumed to be the critical mechanism. We employed a microflow reactor to realize rapid heating and cooling. A significant difference in the reaction rate between the two precursors was observed. Pd was reduced within seconds, but the reduction of Ru was 2 orders of magnitude slower than that of Pd and was not as rapid as previously assumed. Further investigation of the semibatch method was performed to trace changes in the particle sizes and composition. Through quantitative and multilateral evidence, we concluded that the formation of low-crystallinity seeds, followed by solid-state diffusion, is the governing mechanism for the formation of alloyed Pd-Ru nanoparticles.

Matryoshka-type gastro-resistant microparticles for the oral treatment of Mycobacterium tuberculosis

AIM

Production of Matryoshka-type gastroresistant microparticles containing antibiotic-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (NP) against Mycobacterium tuberculosis.

MATERIALS & METHODS

The emulsification and evaporation methods were followed for the synthesis of PLGA-NPs and methacrylic acid-ethyl acrylate-based coatings to protect rifampicin from degradation under simulated gastric conditions.

RESULTS & CONCLUSION

The inner antibiotic-loaded NPs here reported can be released under simulated intestinal conditions whereas their coating protects them from degradation under simulated gastric conditions. The encapsulation does not hinder the antituberculosis action of the encapsulated antibiotic rifampicin. A sustained antibiotic release could be obtained when using the drug-loaded encapsulated NPs. Compared with the administration of the free drug, a more effective elimination of M. tuberculosis was observed when applying the NPs against infected macrophages. The antibiotic-loaded PLGA-NPs were also able to cross an in vitro model of intestinal barrier.

The Effect of Ni Addition onto a Cu-Based Ternary Support on the H₂ Production over Glycerol Steam Reforming Reaction

In the present study, Ni/Ce-Sm-xCu (x = 5, 7, 10 at.%) catalysts were prepared using microwave radiation coupled with sol-gel and followed by wetness impregnation method for the Ni incorporation. Highly dispersed nanocrystallites of CuO and NiO on the Ce-Sm-Cu support were found. Increase of Cu content seems to facilitate the reducibility of the catalyst according to the H₂ temperature-programmed reduction (H₂-TPR). All the catalysts had a variety of weak, medium and strong acid/basic sites that regulate the reaction products. All the catalysts had very high XC3H8O3 for the entire temperature (400⁻750 °C) range; from ≈84% at 400 °C to ≈94% at 750 °C. Ni/Ce-Sm-10Cu catalyst showed the lowest XC3H8O3-gas implying the Cu content has a detrimental effect on performance, especially between 450⁻650 °C. In terms of H₂ selectivity (SH2) and H₂ yield (YH2), both appeared to vary in the following order: Ni/Ce-Sm-10Cu > Ni/Ce-Sm-7Cu > Ni/Ce-Sm-5Cu, demonstrating the high impact of Cu content. Following stability tests, all the catalysts accumulated high amounts of carbon, following the order Ni/Ce-Sm-5Cu < Ni/Ce-Sm-7Cu < Ni/Ce-Sm-10Cu (52, 65 and 79 wt.%, respectively) based on the thermogravimetric analysis (TGA) studies. Raman studies showed that the incorporation of Cu in the support matrix controls the extent of carbon graphitization deposited during the reaction at hand.

Cleavable and thermo-responsive hybrid nanoparticles for on-demand drug delivery

By combining the photothermal ability of copper sulphide nanoparticles (NPs) upon excitation with Near Infrared (NIR) Light and the thermo-responsive properties of the homemade oligo (ethylene glycol) methyl ether methacrylate copolymer we have obtained fragmentable nanocomposites able to release a carried drug on-demand after NIR-light triggering. A complete physico-chemical characterization of the resulting nanoparticles has been carried out and their degradation assessed at different temperatures. Herein, we have also evaluated the drug loading capacity of those nanoparticles and the temperature dependence in their drug release kinetics using bupivacaine hydrochloride as a model drug. For those hybrid nanoparticles, subcytotoxic doses on four different cell lines and their potential interference in cell metabolism, induction of apoptosis, and cell cycle have been evaluated by Alamar Blue fluorometry and flow cytometry.

Rapid on-Chip Assembly of Niosomes: Batch versus Continuous Flow Reactors

The large-scale continuous production of niosomes remains challenging. The inherent drawbacks of batch processes such as large particle polydispersity and reduced batch-to-batch reproducibility are here overcome by using commercially available microfluidic reactors. Compared to the traditional batch-based film hydration method, herein, we demonstrate that it is possible to carry out the homogeneous, large-scale (up to 120 mg/min) production of niosomes using two different synthesis techniques (the thin film hydration method and the emulsification technique). Niosomes particle size can be controlled depending on the need by varying the synthesis temperature. The high cytocompatibility of the resulting niosomes was also demonstrated in this work on three different somatic cell lines. For the first time, the structure of the niosome multilamellar shell was also elucidated using high-resolution transmission electron microscopy (HR-STEM) as well as their colloidal stability over time (6 weeks) under different storage conditions. The morphology of cryo-protected or as-made niosomes was also evaluated by HR-STEM after freeze-drying. Finally, the dual ability of those synthetic, nonionic, surfactant-based vesicles to carry both hydrophilic and hydrophobic molecules was also here demonstrated by using laser scanning confocal microscopy.