Littérature scientifique sur le sujet « Lipid nanovectors »

Ample evidence exists on the role of interleukin-12 (IL-12) in the response against many pathogens, as well as on its remarkable antitumor properties. However, the unexpected toxicity and disappointing results in some clinical trials are prompting the design of new strategies and/or vectors for IL-12 delivery. This study was conceived to further endorse the use of gemini cationic lipids (GCLs) in combination with zwitterionic helper lipid DOPE (1,2-dioleoyl-sn-glycero-3-phosphatidyl ethanol amine) as nanovectors for the insertion of plasmid DNA encoding for IL-12 (pCMV-IL12) into cells. Optimal GCL formulations previously reported by us were selected for IL-12-based biophysical experiments. In vitro studies demonstrated efficient pCMV-IL12 transfection by GCLs with comparable or superior cytokine levels than those obtained with commercial control Lipofectamine2000*. Furthermore, the nanovectors did not present significant toxicity, showing high cell viability values. The proteins adsorbed on the nanovector surface were found to be mostly lipoproteins and serum albumin, which are both beneficial to increase the blood circulation time. These outstanding results are accompanied by an initial physicochemical characterization to confirm DNA compaction and protection by the lipid mixture. Although further studies would be necessary, the present GCLs exhibit promising characteristics as candidates for pCMV-IL12 transfection in future in vivo applications.

Biocompatible nanocarriers can be obtained by lipid extraction from natural sources such as algal biomasses, which accumulate different lipid classes depending on the employed culture media. Lipid aggregates can be distinguished according to supramolecular architecture into lamellar and nonlamellar structures. This distinction is mainly influenced by the lipid class and molecular packing parameter, which determine the possible values of interfacial curvature and thus the supramolecular symmetries that can be obtained. The nanosystems prepared from bio-sources are able to self-assemble into different compartmentalized structures due to their complex composition. They also present the advantage of increased carrier-target biocompatibility and are suitable to encapsulate and vehiculate poorly water-soluble compounds, e.g., natural antioxidants. Their functional properties stem from the interplay of several parameters. Following previous work, here the functionality of two series of structurally distinct lipid nanocarriers, namely liposomes and cubosomes deriving from algal biomasses with different lipid composition, is characterized. In the view of their possible use as pharmaceutical or nutraceutical formulations, both types of nanovectors were loaded with three well-known antioxidants, i.e., curcumin, α-tocopherol and piperine, and their carrier efficacy was compared considering their different structures. Firstly, carrier stability in biorelevant conditions was assessed by simulating a gastrointestinal tract model. Then, by using an integrated chemical and pharmacological approach, the functionality in terms of encapsulation efficiency, cargo bioaccessibility and kinetics of antioxidant capacity by UV-Visible spectroscopy was evaluated. Subsequently, in vitro cytotoxicity and viability tests after administration to model cell lines were performed. As a consequence of this investigation, it is possible to conclude that nanovectors from algal lipids, i.e., cubosomes and liposomes, can be efficient delivery agents for lipophilic antioxidants, being able to preserve and enhance their activity toward different targets while promoting sustained release.

Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan that exists in living systems, and it is a major component of the extracellular matrix. The hyaluronic acid receptor CD44 is found at low levels on the surface of epithelial, haematopoietic, and neuronal cells and is overexpressed in many cancer cells particularly in tumour initiating cells. HA has been therefore used as ligand attached to HA-lipid-based nanovectors for the active targeting of small or large active molecules for the treatment of cancer. This paper describes the different approaches employed for the preparation, characterization, and evaluation of these potent delivery systems.

Understanding the interaction between a carbon nanotube and biological macromolecules such as lipid bilayers is important for the design and development of nanovectors for gene and drug delivery. The forces of penetration and the free energies of rupture of lipid bilayers during nanotube penetration were studied using nonequilibrium, all-atom molecular dynamics simulations for pure POPC and POPC/cholesterol bilayers. The presence of cholesterol did not alter the magnitude of the rupture force and minimally increased the estimated free energy of rupture. However, the ability of the nanotube to disrupt the membrane leading to membrane poration increased with increasing cholesterol content.

In the era of nanoparticulate controlled and site specific drug delivery systems, use of solid lipids to produce first generation lipid nanoparticles, solid lipid nanoparticles (SLN), became a revolutionary approach in the early nineties. The present review is designed to provide an insight into how SLN are finding a niche as promising nanovectors and forms a sound basis to troubleshoot the existing problems associated with traditional systems. Herein, authors had tried to highlight the frontline aspects prominent to SLN. An updated list of lipids, advanced forms of SLN, methods of preparation, characterization parameters, and various routes of administration of SLN are explored in-depth. Stability, toxicity, stealthing, targeting efficiency and other prospectives of SLN are also discussed in detail. The present discussion embodies the potential of SLN, now being looked up by various research groups around the world for their utility in the core areas of pharmaceutical sciences, thereby urging pharmaceutical industries to foster their scale-up.

Hydrophobic PbS nanocrystals (NCs) emitting in the near infrared spectral region were encapsulated in the core of micelles and in the bilayer of liposomes, respectively, to form polyethylene glycol (PEG)-grafted phospholipids.

Les peptides thérapeutiques peuvent traiter de nombreuses pathologies de manière efficace et sélective. Leur biodisponibilité orale est limitée par une forte dégradation liée à l’action de protéases dans le lumen intestinal et par une faible absorption par la barrière intestinale. Nous avons évalué la capacité des nanoparticules lipidiques solides (SLN) et des vecteurs lipidiques nanostructurés (NLC) à augmenter la biodisponibilité orale d’un peptide modèle : le Leuprolide (LEU). L’augmentation de sa lipophilie par formation d’une paire d’ions hydrophobe (HIP) avec le docusate permet d’augmenter significativement le taux d’encapsulation du LEU dans les nanovecteurs. Ceux-ci sont obtenus par homogénéisation haute pression avec une taille de 120 nm et une structure en plaquettes. Malgré leur stabilité dans les milieux gastro-intestinaux simulés, une libération importante de l’actif est observée dans le milieu intestinal à jeun. Vis-à-vis de la dégradation protéolytique, les NLC montrent une protection significative du LEU en présence de trypsine. L’évaluation du passage intestinal sur des monocouches de Caco-2 (modèle entérocyte) et de Caco-2/HT29-MTX (modèle sécrétant des mucines) révèle une internalisation des nanovecteurs mais aucune amélioration de l’absorption. En effet, la morphologie en plaquettes des SLN et NLC associée à la faible stabilité de l’HIP dans le milieu provoquent une libération importante du LEU, annulant la capacité de transport des nanovecteurs à travers la barrière intestinale. Il convient d’améliorer la stabilité de la hydrophobisation pour augmenter la biodisponibilité orale des peptides via l’encapsulation dans des nanovecteurs lipidiques solides
Therapeutic peptides are able to treat a wide variety of diseases with selective and potent action. Their oral bioavailability is strongly limited by an important proteolytic activity in the intestinal lumen and poor permeation across the intestinal border. We have evaluated the capacity of Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid carriers (NLC) to overcome both oral bioavailability limiting aspects, using Leuprolide (LEU) as model peptide. Lipidization of LEU by formation of a Hydrophobic Ion Pair (HIP) with docusate enables a significant increase of peptide encapsulation efficiency in both SLN and NLC. The nanocarriers, obtained by high pressure homogenization, measured 120 nm and were stable in simulated gastro-intestinal fluids. However, due to particles platelet-shape, an important quantity of LEU is released in simulated fasted state intestinal fluid. Regarding the protective effect towards proteolytic degradation, only NLC maintain LEU integrity in presence of trypsin. Intestinal transport, evaluated on Caco-2 (enterocyte-like model) and Caco-2/HT29-MTX (mucin-secreting model) monolayers, show nanocarriers internalization by enterocytes but no improvement of LEU permeability. Indeed, the combination of nanoparticles platelet-shape with the poor stability of the HIP in the transport medium induces a high burst release of the peptide, limiting nanoparticles capacity to transport LEU across the intestinal border. Stability of peptide lipidization needs to be improved to withstand biorelevant medium to benefit from the advantages of encapsulation in solid lipid nanocarriers and consequently improve their oral bioavailability

L’idée directrice de ce travail de thèse était d’introduire au sein de mésophases lipidiques des molécules de β-cyclodextrine (βCD) amphiphiles obtenue par bio-estérification afin d’obtenir des nano-assemblages plurimoléculaires et multi-compartimentés combinant trois fonctions essentielles pour le transport ou la vectorisation de molécules thérapeutiques : (i) la capacité d’incorporer une substance d’intérêt par formation de complexe d’inclusion avec la cyclodextrine ; (ii) être biocompatibles et aptes à passer facilement les barrières biologiques ; (iii) pouvoir co-incorporer une seconde substance d’intérêt, hydrophile ou hydrophobe, dont l’action biologique soit différente de celle assurée par la première substance. L’ensemble des travaux ont porté sur le dérivé βCD-C10 polysubstitué en face secondaire par des chaînes hydrocarbonées en C10 avec un degré moyen de substitution de 7,5. L’association de ce dérivé avec trois catégories de lipides a été envisagée : des tensioactifs micellaires non-ioniques (Brij 98, Polysorbate 80, n-dodécyl-β-D-maltoside), un lipide lyotrope non lamellaire formant des mésophases de type cubique bicontinue (monooléine), un phospholipide s’auto-organisant en bicouches propices à l’obtention de vésicules (dimyristoyl phosphatidylcholine). Selon une démarche principalement physico-chimique, différentes techniques ont été mises en œuvre pour caractériser les systèmes mixtes lipide/βCD-C10 aux échelles moléculaire et supramoléculaire : diffusion-diffraction des rayons X, calorimétrie différentielle, spectrophotométrie d’absorption UV-visible, spectroscopie de fluorescence, diffusion de la lumière statique (turbidimétrie) ou quasi-élastique, microscopie optique et microscopie électronique par cryo-transmission. L’ensemble des résultats démontrent que le dérivé βCD-C10 forme spontanément ou selon un protocole très simple, des assemblages plurimoléculaires mixtes avec les trois catégories de lipides, assemblages dont la topologie dépend de la structure chimique du lipide et du taux de cyclodextrine amphiphile incorporé (tubules, vésicules uni- ou oligolamellaires, cubosomes). Ces assemblages sont stables et capables d’incorporer une substance hôte hydrophobe, notamment les vésicules mixtes tensioactif non-ionique/ βCD-C10 et les cubosomes mixtes monooléine/P80/ βCD-C10
The key idea of this Ph.D. thesis is to introduce amphiphilic β-cyclodextrin molecules (βCD), obtained by bio-transesterification, within lipid mesophases in order to obtain multi-compartment plurimolecular nano-assemblies, which combine three essential functions for transport or delivery of therapeutic molecules: (i) capacity to incorporate a substance of interest through formation of inclusion complexes with the modified cyclodextrin; (i) biocompatibility and ability to easily pass the biological barriers; and (iii) possibility for co-encapsulation of a second substance of interest, a hydrophilic or a hydrophobic one, whose biological action is different from that provided by the first substance. The performed Ph. D. work focused on the β-cyclodextrin derivative βCD-C10 with an average degree of substitution of 7.5 of the secondary face of the macrocycle by hydrocarbon chains C10. The association of this derivative with three classes of amphiphiles was studied: (i) nonionic micellar surfactants (Brij 98, Polysorbate 80, n-dodecyl β-D-maltoside), (ii) a lyotropic nonlamellar lipid forming bicontinuous cubic mesophases (monoolein), and (iii) a phospholipid (dimyristoyl phosphatidylcholine), which self-ssembles into bilayer membranes permitting the production of vesicles.The employed physical-chemical approach involved different techniques for characterization of the mixed βCD-C10/lipid systems at molecular and supramolecular levels: cryo-transmission electron microscopy, X-ray diffraction, differential scanning calorimetry, UV-visible absorption spectroscopy, fluorescence spectroscopy, turbidimetry, and quasi-elastic light scattering.The obtained results indicated that the βCD-C10 derivative forms spontaneously (or via a very simple preparation protocol) plurimolecular mixed nano-assemblies with the three types of lipids. The topologies of the resulting nano-assemblies essentially depend on the chemical structures of the lipids and the degree of incorporation of the amphiphilic cyclodextrin (tubules, unilamellar or oligolamellar vesicles, and cubosomes). These assemblies, namely the mixed vesicles of nonionic surfactant/βCD-C10 and the cubosomes of mixed monoolein/P80/βCD-C10 compositions, are stable and capable of incorporation of hydrophobic guest substances

Le psoriasis est une maladie de peau auto-immune et chronique. Le rhumatisme psoriasique est une de ses principales complications qui est très invalidante pour les patients. Cette pathologie reste encore incurable à ce jour. L'usage des médicaments disponibles actuellement dans le psoriasis est limité par leurs effets secondaires dépendant de la dose et de la durée d'utilisation. Le but de ce travail était de développer des nanovecteurs médicamenteux à base de lipides pour un usage topique, en particulier ciblant l'épiderme viable qui est le site principal de la physiopathologie du psoriasis, mais aussi le derme et au-delà pour atteindre les articulations endommagées. Grâce à une nouvelle technique que nous avons développé et optimisé, le double déplacement de solvants, basée sur une organisation des phospholipides en deux temps, nous avons préparé des vésicules lipidiques encapsulant du diclofénac d'une part et de la ciclosporine A 'autre part. Ensuite, nous avons évalué leur aptitude à traverser la peau et cibler les régions d'intérêt. Après une étude systématique permettant d'optimiser les paramètres de préparation, les vésicules lipidiques encapsulant le diclofénac et la cyclosporine A ont montré une efficacité d'encapsulation (EE%) comprise entre 50% et 90% respectivement, selon la concentration en phospholipides. Après réalisation des études in vitro sur peau de cochon, nous avons observé que la formulation contenant une concentration basse en phospholipides (8,5 mg / mL) permettait d'encapsuler plus de 80% du diclofénac et de cibler le derme et au-delà. La formulation de vésicules lipidiques chargées de cyclosporine A qui encapsule la quantité la plus élevée (environ 80%) était également celle contenant la concentration basse de phospholipides. Contrairement au diclofénac, cette formulation n'était pas la meilleure pour cibler une couche profonde de la peau comme l'épiderme viable, alors que c'était le cas pour la formulation avec une concentration élevée de phospholipides (15 mg / mL), bien que l'EE% était d'environ 55%. Le double déplacement de solvant est une technique très prometteuse de préparation de vésicules lipidiques, capable de produire une population monodisperse d'échelle nanométrique. Cette méthode n'est que légèrement impactée lors d'une transposition d'échelle et serait donc facile à mettre en oeuvre à l'échelle industrielle. Cette méthode a été conçue dès le début pour utiliser des solvants favorisant la pénétration cutanée mais l'étendue de ces applications reste à explorer
Psoriasis is an auto-immune and chronic skin disease. Psoriatic arthritis is the main complication which is very disabling for patients. This pathology still remains incurable to date. The currently psoriasis indicated medicines use is limited by their side effects which are dose and use duration dependent. The aim of this work was to develop lipid based nanocarriers for skin targeting, especially the viable epidermis which is the main site of psoriasis physiopathology but also the dermis and beyond in order to reach the damaged articulations. Thanks to a new technique we developed and optimized called the double solvent displacement, based on a two-step phospholipid organization, we prepared diclofenac and cyclosporine A loaded lipid vesicles. Then, we evaluated their potential to cross the skin and target the skin layers of interest. After a systematic study to optimize preparation parameters, diclofenac and cyclosporine A loaded lipid vesicles displayed an encapsulation efficiency (EE %) between 50% and 90% respectively, according to the phospholipid concentration. After in vitro skin studies, we observed that the formulation containing the lower phospholipid concentration (8.5 mg/mL) allowed to encapsulate more than 80% of diclofenac and also to target the dermis and beyond. The formulation of cyclosporine A loaded lipid vesicles which encapsulates the higher amount (around 80%) is also the one containing the lower phospholipid concentration. Unlike to diclofenac, this formulation was not the better to target the viable epidermis whereas the formulation with the higher phospholipid concentration (15 mg/mL) was even though the EE% was of around 55%. The double solvent displacement is a very promising technique of lipid vesicle preparation, capable to produce monodisperse population of nanoscale carriers. This method is hardly impacted during scale-up and would be easy to implement at an industrial scale. This method was designed from the beginning to use skin penetration enhancer solvents but the scope of its applications still remains to be explored

La leishmaniose viscérale (VL) est une anthropozoonose causée par un parasite protozoaire unicellulaire appartenant au genre Leishmania. Parmi les 20 espèces de Leishmania pathogènes pour l’Homme, Leishmania donovani et Leishmania infantum sont les agents les plus importants responsables de la VL et sont la cause de problèmes de santé touchant 400 000 personnes par an. La VL est létale si non traitée, elle est responsable de la mort de 30 – 40 000 personnes par an. Et pourtant, l’Organisation mondiale de la santé définit cette maladie comme négligée. Dans le manuscrit présenté, nous proposons la formulation et l’évaluation de deux nouveaux types de nanovecteurs : les nanocomplexes d’acide hyaluronique/poly-L-arginine associant la pentamidine et les nanocapsules lipidiques encapsulant la miltéfosine. Les deux systèmes ont été produits en continu grâce à un système microfluidique et ont été caractérisés en termes de physicochimie. L’évaluation des NCs a été poursuivie avec une étape de lyophilisation et une évaluation plus poussée (techniques de diffusion de la lumière : statique, dynamique et multiangle). Les deux systèmes sont hémocompatibles, ils n’induisent pas d’hémolyse, leur activation du complément est très modérée voire faible et ils n’ont exercé qu’une toxicité faible sur des modèles de macrophages. Lors de l’évaluation sur une co culture macrophage/leishmanie, les deux systèmes ont montré une bonne efficacité antiparasitaire. Les NCs et les LNCs sont prometteuses en tant que potentiels nanomédicaments dans le traitement de la VL du fait de leur efficacité, sécurité et possibilité de transposition d’échelle
Visceral Leishmaniasis (VL) is a vector-borne anthropozoonosis caused by aunicellular parasitic protozoan of the Leishmania genus. Among the 20 Leishmania species responsible for human diseases, Leishmania donovani and Leishmania infantum are the two most important agents causing VL and are responsible for substantial health problems affecting 400,000 people per year. The disease is lethal if untreated, leading to the death of 30- 40,000 people yearly and yet the world health organization classified this disease as neglected. In the present work, we proposed the formulation and evaluation of two new types of nanocarriers : the hyaluronic acid/poly-L-arginine nanocomplexes (NCs) associating pentamidine and the lipid nanocapsules loaded with miltefosine (LNCs). Both systems were formulated with a microfluidic device in a continuous process, and both systems were characterized in physicochemical terms. The evaluation of the NCs was pushed further with a freeze-drying and a thorough characterization using several techniques (dynamic lights cattering, static light scattering, multi-angle light scattering, nanotracking analysis). Both systems were hemocompatible as they induced no hemolysis, a moderate to weak complement activation and an extremely low toxicity on macrophages. When assessed on a macrophage/leishmania co-culture model, both systems showed a good efficacy. NCs and LNCs are promising nanomedicines to treat leishmaniasis as they show good signs of potential efficacy, safety, and scale-up possibilities

Nanotechnologies include a wide range of devices of nanometer scale size, which find application in many different fields, such as medicine, aerospace and energy production, to name but a few. Among these, lipid-based nanoparticles have been the longest-studied nanocarriers since they are the least toxic for in vivo applications. The use of nanotechnology in agriculture is relatively new, especially dealing with plant protection and production. Since a transition from an intensive farming based on the massive use of pesticides and conventional phytochemicals, towards a more sustainable one is by now mandatory, the development of alternative formulations has been investigated in this work. Specifically, two natural matrixes were used as source of physiological lipids for the fabrication of nanoparticles, which were loaded with plant-derived compounds. The design, the structural characterization and finally, the testing of these nanovectors, are presented and discussed in the first and second section of this thesis. Moreover, a formulation of co-crystals mainly composed of natural constituents was provided by the Department of Chemistry, Life Sciences and Environmental Sustainability of the University of Parma and tested as antimicrobial. Results of this experimentation are shown in the last section of the thesis. In the first section, a specifically designed methodology for phytohormones’ application on olive cuttings is presented and experimented. Olive pomace was used as lipid source for the development of nanocarriers delivering auxins as root-promoting phytohormones. Auxins are poorly soluble in water, thus lipid nanovectors were fabricated as carriers for their delivering to the roots, to improve their plant availability. In addition, the biocompatibility of these devices was improved choosing olive pomace as raw material for the manufacturing, and olive cuttings as final target of the experimentation, originating a green circle starting from olive waste and ending with olive plant itself. The second part of this thesis deals with the development of lipid-based nanocarriers derived from the microalga Nannochloropsis sp. Similarly to auxins’ carrier-mediated transport, the obtained nanodevices were used to overcome the poor water solubility of the bioactive molecule to be delivered, thymol, and also to reduce its volatilization. This terpenoid belongs to a large family of plant-derived compounds which have received remarkable attention because of the peculiar characteristics displayed as antimicrobial, antifungal, insecticidal and antioxidant natural agents. An evaluation of the antibacterial activity of the thymol-delivering nanovectors was carried out against a gram-negative bacterium affecting tomato and pepper plants. Finally, the third section is dedicated to a project in collaboration with the Department of Chemistry, Life Sciences and Environmental Sustainability of the University of Parma, where a powdery formulation of co-crystals specifically designed for the delivery of terpenoids was developed. A set of six co-crystals was synthesized matching thymol, eugenol and carvacrol with hexamethylenetetramine and phenazine in a specific stoichiometric ratio. The release profile of the bioactive molecules from the co-crystals was determined and the antibacterial and fungicidal activity displayed by this formulation was studied in vitro against six bacterial and three fungi species. Despite the different composition, state of matter and final purpose of use, all the systems studied during this PhD were specifically designed to favor the association with the compounds to be loaded, in order to overcome the poor water solubility displayed by auxins and terpenoids. The molecules selected for the delivery were all plant-derived and the composition of the three formulations was primarily based on the use of natural constituents extracted, purified or recovered by biological matrixes, being one of the prime intents that of proposing a biocompatible and low-toxic alternative to the conventional phytochemicals. L’impiego di ingenti quantitativi di antiparassitari, diserbanti ed altri prodotti chimici di sintesi, ha fortemente compromesso la qualità dei raccolti e la produttività dei terreni agricoli, con serie ripercussioni sull’ambiente, sulla salute dell’uomo e degli animali. In Europa una maggior sensibilità dell’opinione pubblica verso queste tematiche e l’urgenza di trovare valide alternative ai metodi più comunemente utilizzati, hanno richiamato l’attenzione di molti dei paesi membri, che da alcuni anni stanno proponendo politiche ambientali più sostenibili. In questo contesto, le nanotecnologie rappresentano uno strumento di supporto utile allo sviluppo di nuove strategie e metodologie di trattamento in ambito agronomico. Nella presente tesi di dottorato sono state affrontate due problematiche di interesse primario per questo settore, vale a dire produttività e impiego di antiparassitari. A tal fine sono stati realizzati dei nanovettori lipidici utilizzando biorisorse naturali, con l’obiettivo ultimo di promuovere l’efficacia delle molecole veicolate dal nanosistema stesso. La scelta di utilizzare questo tipo di nanotecnologia nasce dai numerosi vantaggi d’impiego dei nanovettori a base lipidica, la cui composizione li rende particolarmente biocompatibili e biodegradabili. Nel primo caso è stato ideato e sviluppato un formulato per il trasporto di auxine derivato da uno scarto del processo di spremitura delle olive, la sansa di oliva. Le auxine sono ormoni vegetali comunemente utilizzati in floricoltura e nella riproduzione per talea per promuovere lo sviluppo e l’accrescimento della pianta. La scarsa idrosolubilità di questi composti, tuttavia, ne limita la biodisponibilità e, di conseguenza, l’efficacia di azione. Questo inconveniente è stato aggirato caricando le auxine nei nanovettori lipidici ottenuti da sansa di oliva, la cui struttura è stata caratterizzata tramite tecniche di Dynamic Light Scattering, potenziale zeta e Small-angle X-ray Scattering, e la cui efficacia è stata infine testata su talee di olivo appartenenti a tre differenti cultivar. I risultati ottenuti hanno mostrato un aumento della percentuale di radicazione rispetto ai trattamenti convenzionali in due delle tre cultivar selezionate. Nel secondo caso Nannochloropsis sp., una microalga marina principalmente costituita di lipidi, è stata scelta come biorisorsa per la realizzazione di nanovettori caricati con timolo. Questo terpenoide si ritrova nella miscela aromatica di numerose specie vegetali ed è un potente antibatterico e fungicida naturale. La sua natura volatile, però, ne pregiudica l’efficacia a lungo termine, limitandone fortemente le potenzialità. Il carattere idrofobico del timolo è stato sfruttato per favorirne l’associazione con i nanovettori lipidici ottenuti da alga che, fungendo da veri e propri siti di accumulo, sono stati sperimentati come agenti di trasporto dell’antibatterico in esperimenti in vitro condotti contro un batterio patogeno della pianta di pomodoro. I risultati di questi test hanno mostrato una completa inibizione della crescita batterica in presenza di nanovettori carichi di timolo per concentrazioni pari o superiori a 250 ppm. Struttura e dimensioni dei nanovettori sono state determinate tramite le tecniche sopracitate e il timolo caricato al loro interno è stato quantificato mediante gas-cromatografia accoppiata a spettrometria di massa. Infine, l’utilizzo di timolo, carvacrolo ed eugenolo come antimicrobici naturali, è stato ulteriormente indagato sperimentando l’efficacia di una formulazione solida, alternativa ai nanovettori lipidici in solvente acquoso. Questi tre terpenoidi sono stati scelti per lo sviluppo di sei co-cristalli, combinando ciascuno di essi con fenazina o esametilentetrammina (coformeri) secondo un preciso rapporto stechiometrico; in tal modo sono stati ottenuti dei formulati di natura polverulenta, la cui bioattività è stata saggiata in vitro contro sei specie batteriche e tre fungine fitopatogene o benefiche per le piante. I risultati ottenuti hanno mostrato come l’efficacia dei monoterpeni venga in alcuni casi potenziata dalla combinazione con il coformero, poiché a parità di concentrazione, alcuni co-cristalli mostrano un’azione biocida significativamente superiore a quella dei corrispondenti costituenti puri. In conclusione, in questa tesi vengono presentate tre formulazioni a base di composti derivati dalle piante, di cui due in solvente acquoso e una allo stato solido; la loro efficacia è stata studiata tramite test di laboratorio con l’intento finale di ideare e realizzare prodotti alternativi ai fitofarmaci tradizionali per possibili impieghi in agricoltura.