Improving bioavailability of insoluble payloads through PLGA nanotechnology

Bioactive molecules are a cluster of natural or synthetic compounds, which modu- late actions in the body promoting good health. Furthermore, they have been ap- plied in the prevention of cancer, heart disease, and other diseases for their antiox- idant, anti-inflammatory, anti-microbial, anti-cancer properties. Among them, many are hydrophobic or poorly soluble nutrients, such as phenolic compounds, ca- rotenoids, essential oils, essential fatty acids, insoluble peptides, and vitamins. Their low water solubility is the limiting factor for their use in both nutraceutical and pharmacological industries. In fact, drugs with poor water solubility show a slower absorption rate, which can lead to inadequate bioavailability making the drug ineffective. Furthermore, hydrophobic molecules can also be used as bio- probe for imaging purpose. Narrow bandwidth emissions and large Stokes shifts make lanthanide complexes interesting as versatile molecular probes of biological systems. Nevertheless, they are not widely used for imaging purpose since their luminescence is completely quenched in aqueous environment. In this scenario, nanoencapsulation through the use of polymeric nanoparticles (NPs ) could be an effective solution to improve solubility and protection of the insoluble payload with consequent increase in bioavailability and action. Poly lac- tic-co-glycolic acid (PLGA) is a synthetic copolymer of lactic acid and glycolic acid of remarkable interest for potential applications in biomedicine; indeed, for its biodegradability and biocompatibility, it has been approved for human use both by Food and Drug Administration (FDA) and European Medicine Agency (EMA). In this thesis, we want to give several proofs of concept about the huge potentiality of PLGA nanoparticles in medical purpose. We used single emulsion methos (O/W) to encapsulate natural bioactive molecules producing planted-derived PLGA nanocarriers enabling anti-inflammatory and antioxidant activity when the polyphe- nol Oxyresveratrol has been incorporated into PLGA NPs. Moreover, an osteogenic promoting action has been observed when PLGA NPs have been embedded with Fisetin (a natural flavonoid).Since PLGA can deliver more than one payload simultaneously, we also produced PLGA nanoassemblies able to combine antibacterial activity with physical treat- ments (such as magnetic and photothermic hyperthermia). Finally, we exploited the shielding properties of PLGA to preserve the luminescence of NIR-emitting lantha- nide complexes in aqueous environment. Therefore, we produced a NIR-CPL probe based on PLGA for bioassay imaging. To summarise, during the past three years we were able to use PLGA encapsulation technology to make natural or synthetic compounds bioavailable, even if naturally water insoluble, and use the loaded nanomaterials in in-vitro experiments assessing the activity of the encapsulated material, paving the way for their application in in- vivo tests and eventual use in nanomedicine

Oxyresveratrol-Loaded PLGA Nanoparticles Inhibit Oxygen Free Radical Production by Human Monocytes: Role in Nanoparticle Biocompatibility

Oxyresveratrol, a polyphenol extracted from the plant Artocarpus lakoocha Roxb, has been reported to be an antioxidant and an oxygen-free radical scavenger. We investigated whether oxyresveratrol affects the generation of superoxide anion (O2 ) by human monocytes, which are powerful reactive oxygen species (ROS) producers. We found that oxyresveratrol inhibited the O2 production induced upon stimulation of monocytes with -glucan, a well known fungal immune cell activator. We then investigated whether the inclusion of oxyresveratrol into nanoparticles could modulate its effects on O2 release. We synthesized poly(lactic-co-glycolic acid) (PLGA) nanoparticles, and we assessed their effects on monocytes. We found that empty PLGA nanoparticles induced O2 production by resting monocytes and enhanced the formation of this radical in -glucan-stimulated monocytes. Interestingly, the insertion of oxyresveratrol into PLGA nanoparticles significantly inhibited the O2 production elicited by unloaded nanoparticles in resting monocytes as well as the synergistic effect of nanoparticles and -glucan. Our results indicate that oxyresveratrol is able to inhibit ROS production by activated monocytes, and its inclusion into PLGA nanoparticles mitigates the oxidative effects due to the interaction between these nanoparticles and resting monocytes. Moreover, oxyresveratrol can contrast the synergistic effects of nanoparticles with fungal agents that could be present in the patient tissues. Therefore, oxyresveratrol is a natural compound able to make PLGA nanoparticles more biocompatible

Oxyresveratrol Inhibits R848-Induced Pro-Inflammatory Mediators Release by Human Dendritic Cells Even When Embedded in PLGA Nanoparticles

Oxyresveratrol, a stilbene extracted from the plant Artocarpus lakoocha Roxb., has been reported to provide a considerable anti-inflammatory activity. Since the mechanisms of this therapeutic action have been poorly clarified, we investigated whether oxyresveratrol affects the release of the pro-inflammatory cytokines IL-12, IL-6, and TNF-\u3b1 by human dendritic cells (DCs). We found that oxyresveratrol did not elicit per se the release of these cytokines, but inhibited their secretion induced upon DC stimulation with R848 (Resiquimod), a well-known immune cell activator en-gaging receptors recognizing RNA viruses. We then investigated whether the inclusion of ox-yresveratrol into nanoparticles promoting its ingestion by DCs could favor its effects on cytokine release. For this purpose we synthesized and characterized poly(lactic-co-glycolic acid) (PLGA) nanoparticles, and we assessed their effects on DCs. We found that bare PLGA nanoparticles did not affect cytokine secretion by resting DCs, but increased IL-12, IL-6, and TNF-\u3b1 secretion by R848-stimulated DCs, an event known as \u201cpriming effect\u201d. We then loaded PLGA nanoparticles with oxyresveratrol and we observed that oxyresveratrol-bearing particles did not stimulate the cytokine release by resting DCs and inhibited the PLGA-dependent enhancement of IL-12, IL-6, and TNF-\u3b1 secretion by R848-stimulated DCs. The results herein reported indicate that oxyresveratrol suppresses the cytokine production by activated DCs, thus representing a good anti-inflammatory and immune-suppressive agent. Moreover, its inclusion into PLGA nanoparticles mitigates the pro-inflammatory effects due to cooperation between nanoparticles and R848 in cytokine release. Therefore, oxyresveratrol can be able to contrast the synergistic effects of nanoparticles with microorganisms that could be present in the patient tissues, therefore overcoming a condition unfavorable to the use of some nanoparticles in biological systems

Ln(III) Complexes Embedded in Biocompatible PLGA Nanoparticles as Potential Vis-to-NIR Optical Probes

In this contribution, we present the spectroscopic study of two NIR emitting hydrophobic heteroleptic (R,R)-YbL1(tta) and (R,R)-NdL1(tta) complexes (with tta = 2-thenoyltrifluoroacetonate and L1 = N,N0 -bis(2-(8-hydroxyquinolinate)methylidene)-1,2-(R,R or S,S)-cyclohexanediamine), both in methanol solution and embedded in water dispersible and biocompatible poly lactic-co-glycolic acid (PLGA) nanoparticles. Thanks to their absorption properties in a wide range of wavelengths extending from the UV up to the blue and green visible regions, the emission of these complexes can be effectively sensitized using visible radiation, which is much less harmful to tissues and skin than the UV one. The encapsulation of the two Ln(III)-based complexes in PLGA allows us to preserve their nature, making them stable in water and to test their cytotoxicity on two different cell lines, with the aim of using them in the future as potential bioimaging optical probes

Near Infared Circularly Polarized Luminescence from water stable organic nanoparticles containing a chiral Yb(III) complex

We report the first example of very efficient NIR Circularly Polarized Luminescence (CPL) (around 970 nm) in water, obtained thanks to the combined use of a chiral Yb complex and of poly lactic-co-glycolic acid (PLGA) nanoparticles. [Yb L (tta) 2 ]CH 3 COO ( L = N, N'-bis(2-pyridylmethylidene)-1,2-( R,R + S,S ) cyclohexanediamine and tta = 2-thenoyltrifluoroacetonate) shows good CPL in organic solvents, because the tta ligands efficiently sensitize Yb NIR luminescence and the readily prepared chiral ligand L endows the complex with the necessary dissymmetry. PLGA nanoparticles incorporate the complex and protect the metal ion from the intrusion of solvent molecules, while ensuring biocompatibility, water solubility and stability to the complex. Hydrophilic NIR-CPL optical probes can find applications in the field of NIR-CPL bio-assays

Embedding Biomimetic Magnetic Nanoparticles Coupled with Peptide AS-48 into PLGA to Treat Intracellular Pathogens

Among the strategies employed to overcome the development of multidrug-resistant bacteria, directed chemotherapy combined with local therapies (e.g., magnetic hyperthermia) has gained great interest. A nano-assembly coupling the antimicrobial peptide AS-48 to biomimetic magnetic nanoparticles (AS-48-BMNPs) was demonstrated to have potent bactericidal effects on both Gram-positive and Gram-negative bacteria when the antimicrobial activity of the peptide was combined with magnetic hyperthermia. Nevertheless, intracellular pathogens remain challenging due to the difficulty of the drug reaching the bacterium. Thus, improving the cellular uptake of the nanocarrier is crucial for the success of the treatment. In the present study, we demonstrate the embedding cellular uptake of the original nano-assembly into THP-1, reducing the toxicity of AS-48 toward healthy THP-1 cells. We optimized the design of PLGA[AS-48-BMNPs] in terms of size, colloidal stability, and hyperthermia activity (either magnetic or photothermal). The stability of the nano-formulation at physiological pH values was evaluated by studying the AS-48 release at this pH value. The influence of pH and hyperthermia on the AS-48 release from the nano-formulation was also studied. These results show a slower AS-48 release from PLGA[AS-48-BMNPs] compared to previous nano-formulations, which could make this new nano-formulation suitable for longer extended treatments of intracellular pathogens. PLGA[AS-48-BMNPs] are internalized in THP-1 cells where AS-48 is liberated slowly, which may be useful to treat diseases and prevent infection caused by intracellular pathogens. The treatment will be more efficient combined with hyperthermia or photothermia.FEDER Operational ProgramProyectos de I + D + I, del Plan Andaluz de Investigacion, Desarrollo e Innovacion B-BIO-432-UGR20 B-BIO-268-UGR20 B-CTS-216-UGR20 A-FQM-492-UGR20Instituto de Salud Carlos III European Commission P20-00346 P20_00339 P20-00233Spanish Government PI20-01658Federation of European Microbiological Societies (FEMS) EC2019-005930-P PDC2021-121135.100 FEMS-GO-2020-20

Fisetin: an integrated approach to identify a strategy promoting osteogenesis

Flavonoids may modulate the bone formation process. Among flavonoids, fisetin is known to counteract tumor growth, osteoarthritis, and rheumatoid arthritis. In addition, fisetin prevents inflammation-induced bone loss. In order to evaluate its favorable use in osteogenesis, we assayed fisetin supplementation in both in vitro and in vivo models and gathered information on nanoparticle-mediated delivery of fisetin in vitro and in a microfluidic system. Real-time RT-PCR, Western blotting, and nanoparticle synthesis were performed to evaluate the effects of fisetin in vitro, in the zebrafish model, and in ex vivo samples. Our results demonstrated that fisetin at 2.5 μM concentration promotes bone formation in vitro and mineralization in the zebrafish model. In addition, we found that fisetin stimulates osteoblast maturation in cell cultures obtained from cleidocranial dysplasia patients. Remarkably, PLGA nanoparticles increased fisetin stability and, consequently, its stimulating effects on RUNX2 and its downstream gene SP7 expression. Therefore, our findings demonstrated the positive effects of fisetin on osteogenesis and suggest that patients affected by skeletal diseases, both of genetic and metabolic origins, may actually benefit from fisetin supplementation

Efficiency of Chitosan Nanocarriers in Vaccinology for Mucosal Immunization

The mucosal barrier constitutes a huge surface area, close to 40 m2 in humans, located mostly in the respiratory, gastrointestinal and urogenital tracts and ocular cavities. It plays a crucial role in tissue interactions with the microbiome, dietary antigens and other environmental materials. Effective vaccinations to achieve highly protective mucosal immunity are evolving strategies to counteract several serious diseases including tuberculosis, diphtheria, influenzae B, severe acute respiratory syndrome, Human Papilloma Virus infection and Acquired Immune Deficiency Syndrome. Interestingly, one of the reasons behind the rapid spread of severe acute respiratory syndrome coronavirus 2 variants has been the weakness of local immunization at the level of the respiratory mucosa. Mucosal vaccines can outperform parenteral vaccination as they specifically elicit protective mucosal immune responses blocking infection and transmission. In this scenario, chitosan-based nanovaccines are promising adjuvants-carrier systems that rely on the ability of chitosan to cross tight junctions and enhance particle uptake due to chitosan-specific mucoadhesive properties. Indeed, chitosan not only improves the adhesion of antigens to the mucosa promoting their absorption but also shows intrinsic immunostimulant abilities. Furthermore, by finely tuning the colloidal properties of chitosan, it can provide sustained antigen release to strongly activate the humoral defense. In the present review, we agnostically discuss the potential reasons why chitosan-based vaccine carriers, that efficiently elicit strong immune responses in experimental setups and in some pre-clinical/clinical studies, are still poorly considered for therapeutic formulations

SESAMO: An integrated framework for gathering, managing and sharing environmental data

ICT systems are widely adopted for environmental management, but existing solutions address limited tasks and compose a plethora of heterogeneous tools, which impose a great additional effort on the operators. This work presents SESAMO, a novel framework to provide the operators with a unique tool for gathering, managing and merging environmental and territorial data. SESAMO uses WSNs for providing pervasive monitoring of environmental phenomena and exploits a multi-tier infrastructure in order to integrate data coming from heterogeneous information sources

Complexes of rare earth ions embedded in Poly(lactic-co-glycolic acid) (PLGA) nanoparticles: Characterization and spectroscopic study

Several Eu(III) complexes [(Eu(L1)(tta)2(H2O)] 19CF3SO3, Eu(L2)(NO3)3 and Eu(L3) with L1 = N,N\u2019-bis(2-pyridylmethylidene)-1,2-(R,R+S,S)-cyclohexanediamine, L2 = N, N\u2019-bis(2-quinolylmethylidene)- 1,2-(R,R+S,S)-cyclohexanediamine, L3 N-quinolyl-N,N\u2019,N\u2019-trans-l,2-cyclohexylenediaminetriacetic acid and tta = 2-thenoyltrifluoroacetyl-acetonate] and one Y(III) complex [(Y(L1)(tta)2(H2O)] 19CF3SO3] have been embedded, with a different degree of efficiency, in Poly(lactic-co-glycolic acid) (PLGA) matrix by using two different composition [Poly(lactic(50%)-co-glycolic acid(50%), briefly PLGA 50:50 and Poly(lactic(75%)-co-glycolic acid(25%), briefly PLGA 75:25], giving nanoparticles characterized by a monodispersed distribution of the size (diameter around 200 nm). The [Eu(L1)(tta)2(H2O)] 19CF3SO3 shows the most efficient Eu(III) luminescence (\u278Tot = 25%) when embedded in PLGA 75:25. The release of the complex over the time in aqueous buffered solution has been followed by means of the decrease of Eu(III) luminescence and it is faster upon increasing the temperature to 37\ub0C, in particular for the PLGA 50:50 system, whose melting temperature (Tm) is lower (33\ub0C) than both the Tm of PLGA 75:25 (38\ub0C) and the basal one