Publications

The sustainable synthesis of urea from ammonia (NH3) and carbon dioxide (CO2) using ultraporous permanently polarized hydroxyapatite (upp-HAp) as catalyst has been explored as an advantageous CO2-revalorization strategy. As the simultaneous activation of N-2 and CO2 (single-step) demands an increase of the reaction conditions, we have re-visited the industrial two-step Bazarov reaction. upp-HAp has been designed as a stable multifunctional catalyst capable of promoting both CO2 and NH3 adsorption for their subsequent C-N bond formation. Herein we report the synthesis of 1 mmol/g(cat) of urea with a selectivity of 97 % under strictly mild conditions (95-120 degrees C and 1 bar of CO2; without applying any electrical currents or UV irradiation) which represents an efficiency of similar to 2 % and similar to 30 % with respect to the NH3 and CO2 content, respectively. The study of the NH3 content, products adsorbed in the catalyst, presence of intermediates and temperature of the reaction allows unveiling the great potential of upp-HAp as a green catalyst for sustainable Bazarov reactions. Results suggest that the double-step approach could be more advantageous for both synthesizing urea and as a CO2-revalorization strategy, which in turn promotes the development of specific technologies for the independent synthesis of green NH3.

JTD Keywords: Co2-revalorization, Hydroxyapatite, Permanently polarized materials, Tsp treatment, Ure, Urea

Enzymatic nanomotors harvest kinetic energy through the catalysis of chemical fuels. When a drop containing nanomotors is placed in a fuel-rich environment, they assemble into ordered groups and exhibit intriguing collective behaviour akin to the bioconvection of aerobic microorganismal suspensions. This collective behaviour presents numerous advantages compared to individual nanomotors, including expanded coverage and prolonged propulsion duration. However, the physical mechanisms underlying the collective motion have yet to be fully elucidated. Our study investigates the formation of enzymatic swarms using experimental analysis and computational modelling. We show that the directional movement of enzymatic nanomotor swarms is due to their solutal buoyancy. We investigate various factors that impact the movement of nanomotor swarms, such as particle concentration, fuel concentration, fuel viscosity, and vertical confinement. We examine the effects of these factors on swarm self-organization to gain a deeper understanding. In addition, the urease catalysis reaction produces ammonia and carbon dioxide, accelerating the directional movement of active swarms in urea compared with passive ones in the same conditions. The numerical analysis agrees with the experimental findings. Our findings are crucial for the potential biomedical applications of enzymatic nanomotor swarms, ranging from enhanced diffusion in bio-fluids and targeted delivery to cancer therapy. Enzymatic nanomotors exhibit collective behaviour in fuel-rich environments, forming swarms with enhanced propulsion and coverage. This study investigates the factors affecting swarm movement, revealing that solutal buoyancy drives their motion, with potential biomedical applications like targeted drug delivery.

JTD Keywords: Ammonia, Behavior, Carbon dioxide, Catalysis, Computer simulation, Kinetics, Motion, Nanostructures, Powered nanomotors, Propulsion, Urease, Viscosity

This study investigates the synthesis and optimization of nanobots (NBs) loaded with pDNA using the layer-by-layer (LBL) method and explores the impact of their collective motion on the transfection efficiency. NBs consist of biocompatible and biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles and are powered by the urease enzyme, enabling autonomous movement and collective swarming behavior. In vitro experiments were conducted to validate the delivery efficiency of fluorescently labeled NBs, using two-dimensional (2D) and three-dimensional (3D) cell models: murine urothelial carcinoma cell line (MB49) and spheroids from human urothelial bladder cancer cells (RT4). Swarms of pDNA-loaded NBs showed enhancements of 2.2- to 2.6-fold in delivery efficiency and 6.8- to 8.1-fold in material delivered compared to inhibited particles (inhibited enzyme) and the absence of fuel in a 2D cell culture. Additionally, efficient intracellular delivery of pDNA was demonstrated in both cell models by quantifying and visualizing the expression of eGFP. Swarms of NBs exhibited a >5-fold enhancement in transfection efficiency compared to the absence of fuel in a 2D culture, even surpassing the Lipofectamine 3000 commercial transfection agent (cationic lipid-mediated transfection). Swarms also demonstrated up to a 3.2-fold enhancement in the amount of material delivered in 3D spheroids compared to the absence of fuel. The successful transfection of 2D and 3D cell cultures using swarms of LBL PLGA NBs holds great potential for nucleic acid delivery in the context of bladder treatments.

JTD Keywords: Animals, Barrier, Cell line, tumor, Dna, Drug delivery, Drug-delivery, Enzyme catalysis, Gene delivery, Gene transfer techniques, Humans, Lactic acid, Mice, Nanobots, Nanoparticles, Pdna, Plasmids, Polyglycolic acid, Polylactic acid-polyglycolic acid copolymer, Swarming, Transfectio, Transfection, Urease, Urinary bladder neoplasms

Here, we report DNA-based synthetic nanostructures decorated with enzymes (hereafter referred to as DNA-enzyme swimmers) that self-propel by converting the enzymatic substrate to the product in solution. The DNA-enzyme swimmers are obtained from tubular DNA structures that self-assemble spontaneously by the hybridization of DNA tiles. We functionalize these DNA structures with two different enzymes, urease and catalase, and show that they exhibit concentration-dependent movement and enhanced diffusion upon addition of the enzymatic substrate (i.e., urea and H2O2). To demonstrate the programmability of such DNA-based swimmers, we also engineer DNA strands that displace the enzyme from the DNA scaffold, thus acting as molecular brakes on the DNA swimmers. These results serve as a first proof of principle for the development of synthetic DNA-based enzyme-powered swimmers that can self-propel in fluids.

JTD Keywords: Biocatalysis, Catalase, Design, Dna, Hydrogen peroxide, Motor, Nanostructures, Shapes, Urease

Over the past decades, the development of nanoparticles (NPs) to increase the efficiency of clinical treatments has been subject of intense research. Yet, most NPs have been reported to possess low efficacy as their actuation is hindered by biological barriers. For instance, synovial fluid (SF) present in the joints is mainly composed of hyaluronic acid (HA). These viscous media pose a challenge for many applications in nanomedicine, as passive NPs tend to become trapped in complex networks, which reduces their ability to reach the target location. This problem can be addressed by using active NPs (nanomotors, NMs) that are self-propelled by enzymatic reactions, although the development of enzyme-powered NMs, capable of navigating these viscous environments, remains a considerable challenge. Here, the synergistic effects of two NMs troops, namely hyaluronidase NMs (HyaNMs, Troop 1) and urease NMs (UrNMs, Troop 2) are demonstrated. Troop 1 interacts with the SF by reducing its viscosity, thus allowing Troop 2 to swim more easily through the SF. Through their collective motion, Troop 2 increases the diffusion of macromolecules. These results pave the way for more widespread use of enzyme-powered NMs, e.g., for treating joint injuries and improving therapeutic effectiveness compared with traditional methods. The conceptual idea of the novel approach using hyaluronidase NMs (HyaNMs) to interact with and reduce the viscosity of the synovial fluid (SF) and urease NMs (UrNMs) for a more efficient transport of therapeutic agents in joints.image

JTD Keywords: Biological barrier, Clinical research, Clinical treatments, Collective motion, Collective motion,nanomotors,nanorobots,swarming,viscous medi, Collective motions, Complex networks, Enzymatic reaction, Enzymes, Hyaluronic acid, Hyaluronic-acid,ph,viscoelasticity,adsorption,barriers,behavior,ureas, Macromolecules, Medical nanotechnology, Nano robots, Nanomotors, Nanorobots, Swarming, Synovial fluid, Target location, Viscous media, Viscous medium

Polarized hydroxyapatite (p-HAp) has been used as a catalyst for the synthesis of urea coupling N-2, CO2 and water under mild reaction conditions when compared to classical nitrogen fixation reactions, such as the Haber-Bosch process. The reaction of 3 bar of N-2 and 3 bar of CO2 under UV illumination at 120 degrees C (for 48 h) results in a urea yield of 1.5 +/- 0.1 mmol per gram of catalyst (g(c)) with a selectivity close to 80%, whereas the reaction is not successful without UV irradiation. However, the addition of small amounts of NO (314 ppm) produces 15.2 +/- 0.6 and 4.6 +/- 0.4 mmol g(c)(-1) with and without UV illumination, respectively, with the selectivity in both cases being close to 100%. As nitrogen fixation without UV irradiation using p-HAp as a catalyst is a challenge, studies with NO have been conducted varying the reaction conditions (time, pressure and temperature). The results suggest a mechanism based on the production of NH4+ through the oxidation of N-2.

JTD Keywords: Carbon dioxide, Carbon,dinitrogen,reduction,nitrogen,ammonia,dioxid, Catalyst selectivity, Condition, Haber-bosch process, Hydroxyapatite, Irradiation, Metabolism, Mild reaction conditions, Nitrogen fixation, Pressure and temperature, Reaction conditions, Time pressures, Time-temperature, Urea, Uv illuminations, Without uv irradiations, ]+ catalyst

Enzyme-powered micro- and nanomotors make use of biocatalysis to self-propel in aqueous media and hold immense promise for active and targeted drug delivery. Most (if not all) of these micro- and nanomotors described to date are fabricated using a commercially available enzyme, despite claims that some commercial preparations may not have a sufficiently high degree of purity for downstream applications. In this study, the purity of a commercial urease, an enzyme frequently used to power the motion of micro- and nanomotors, was evaluated and found to be impure. After separating the hexameric urease from the protein impurities by size-exclusion chromatography, the hexameric urease was subsequently characterized and used to functionalize hollow silica microcapsules. Micromotors loaded with purified urease were found to be 2.5 times more motile than the same micromotors loaded with unpurified urease, reaching average speeds of 5.5 ?m/s. After comparing a number of parameters, such as enzyme distribution, protein loading, and motor reusability, between micromotors functionalized with purified vs unpurified urease, it was concluded that protein purification was essential for optimal performance of the enzyme-powered micromotor.

JTD Keywords: canavalin, catalysis, delivery, dls, enhanced diffusion, enzyme, lipase immobilization, micromotors, self-propulsion, super-resolution microscopy, urease, Mesoporous silica nanoparticles, Micromotors, Super-resolution microscopy

The low efficacy of current conventional treatments for bacterial infections increases mortality rates worldwide. To alleviate this global health problem, we propose drug-free enzyme-based nanomotors for the treatment of bacterial urinary-tract infections. We develop nanomotors consisting of mesoporous silica nanoparticles (MSNPs) that were functionalized with either urease (U-MSNPs), lysozyme (L-MSNPs), or urease and lysozyme (M-MSNPs), and use them against nonpathogenic planktonic Escherichia coli. U-MSNPs exhibited the highest bactericidal activity due to biocatalysis of urea into NaHCO3 and NH3, which also propels U-MSNPs. In addition, U-MSNPs in concentrations above 200 μg/mL were capable of successfully reducing 60% of the biofilm biomass of a uropathogenic E. coli strain. This study thus provides a proof-of-concept, demonstrating that enzyme-based nanomotors are capable of fighting infectious diseases. This approach could potentially be extended to other kinds of diseases by selecting appropriate biomolecules.

JTD Keywords: biofilms, carbonate, e. coli, enzymatic nanomotors, infections, lysozyme, micromotors, nanomachines, proteins, self-propulsion, Anti-bacterial agents, Biocatalysis, Biofilms, Canavalia, Drug carriers, E. coli, Eliminate escherichia-coli, Enzymatic nanomotors, Escherichia coli, Escherichia coli infections, Humans, Infections, Muramidase, Nanomachines, Nanoparticles, Self-propulsion, Silicon dioxide, Urease, Urinary tract infections

Enzyme-powered nanomotors are an exciting technology for biomedical applications due to their ability to navigate within biological environments using endogenous fuels. However, limited studies into their collective behavior and demonstrations of tracking enzyme nanomotors in vivo have hindered progress toward their clinical translation. Here, we report the swarming behavior of urease-powered nanomotors and its tracking using positron emission tomography (PET), both in vitro and in vivo. For that, mesoporous silica nanoparticles containing urease enzymes and gold nanoparticles were used as nanomotors. To image them, nanomotors were radiolabeled with either I on gold nanoparticles or F-labeled prosthetic group to urease. In vitro experiments showed enhanced fluid mixing and collective migration of nanomotors, demonstrating higher capability to swim across complex paths inside microfabricated phantoms, compared with inactive nanomotors. In vivo intravenous administration in mice confirmed their biocompatibility at the administered dose and the suitability of PET to quantitatively track nanomotors in vivo. Furthermore, nanomotors were administered directly into the bladder of mice by intravesical injection. When injected with the fuel, urea, a homogeneous distribution was observed even after the entrance of fresh urine. By contrast, control experiments using nonmotile nanomotors (i.e., without fuel or without urease) resulted in sustained phase separation, indicating that the nanomotors’ self-propulsion promotes convection and mixing in living reservoirs. Active collective dynamics, together with the medical imaging tracking, constitute a key milestone and a step forward in the field of biomedical nanorobotics, paving the way toward their use in theranostic applications. 124 18

JTD Keywords: cell, reversal, silica nanoparticles, size, step, transport, Administration, intravesical, Animals, Equipment design, Female, Gold, Metal nanoparticles, Mice, Mice, inbred c57bl, Motion, Phantoms, imaging, Positron emission tomography computed tomography, Precision medicine, Propelled micromotors, Robotics, Translational research, biomedical, Urease, Urinary bladder

Concerns have been raised about the long-term accumulating effects of triclocarban, a polychlorinated diarylurea widely used as an antibacterial soap additive, in the environment and in human beings. Indeed, the Food and Drug Administration has recently banned it from personal care products. Herein, we report the synthesis, antibacterial activity and cytotoxicity of novel N,N′-diarylureas as triclocarban analogs, designed by reducing one or more chlorine atoms of the former and/or replacing them by the novel pentafluorosulfanyl group, a new bioisostere of the trifluoromethyl group, with growing importance in drug discovery. Interestingly, some of these pentafluorosulfanyl-bearing ureas exhibited high potency, broad spectrum of antimicrobial activity against Gram-positive bacterial pathogens, and high selectivity index, while displaying a lower spontaneous mutation frequency than triclocarban. Some lines of evidence suggest a bactericidal mode of action for this family of compounds.

JTD Keywords: Antibacterial, Gram-positive, N,N'-diarylureas, Pentafluorosulfanyl, Staphylococcus aureus, Triclocarban

We developed new hybrid nanomaterials, urease/LDH (layered double hydroxides), for the urea detection. The LDH that were prepared by co-precipitation in constant pH and in ambient temperature are hydrotalcites (Mg2Al, Mg3Al) and zaccagnaite (Zn2Al and Zn3Al). The immobilization of urease in these various layered hybrid materials is realized by auto-assembly. The structures of hosted matrices were studied by X-ray diffraction, Absorbance Infrared spectroscopy in ATR mode and Atomic Force Microscopy (AFM). These techniques allowed the characterisation of the urease immobilization and its interactions with LDH chemical groups. The urease was adsorbed and its morphology was conserved in its new environment. Furthermore, the study of catalytic parameters of Urease/LDH biomembranes and of the kinetics reaction of urea hydrolysis shows a good conformation of the enzyme in hydrotalcite matrices and that the affinity is similar to free urease.

JTD Keywords: Ldh hybrid nanomaterials, Surface properties, Urea biosensors, Urease thin films

This review presents the development of new kind of antibody/LDH (layered double hydroxides) hybrid nanomaterials for beta casein detection. The preparation method of the LDH is described. It is based on the co-precipitation of metallic salts in constant pH and temperature. The chosen LDH are hydrotalcites (Mg2AICO3, Mg3AICO3), Zaccagnaite: Zn2AICO3 and hydrocalumite: Ca 2AICI. Finally, the antibody is immobilized into the LDH materials using Layer-by-Layer method by autoassembly. In this work, we studied the surface properties of the prepared hybrid biomembranes using X-ray diffraction, Infrared spectroscopy in ATR mode and Atomic Force Microscopy (AFM). These techniques allow describing the antibody immobilization and its interactions with LDH. The antibody was adsorbed and its morphology was conserved in its new environment after more than 15 days continuously in PBS solution, promising a constant biosensor performance.

JTD Keywords: Anti β-casein antibody, Antibody immobilization, Ldh hybrid biomaterials, Urea biosensors