1,721,069 research outputs found
BIOCONIUGATI ENZIMA-NANOPARTICELLA POLIMERICA: SINTESI, CARATTERIZZAZIONE ED APPLICAZIONI BIOTECNOLOGICHE
No full textBiotechnological routes to synthesize peptide based hydrogels in aqueous medium
No full textPeptide applications are growing significantly in the field of biomedicine (e.g.immunology, cell signaling, etc.). A recent projection valued that the global peptidetherapeutics market would be worth nearly $2 billion in 2010. Such a significant andrapid development is due to the major clinical value that the specificity of peptides hasbeen acknowledged. A growing number of applications in a wide range of treatments forsuch conditions as cancers, allergies, Parkinson's, multiple sclerosis, and heart failure iscurrently under development, with more than 400 peptide based drugs in advancedpreclinical phases worldwide to this date. Among peptides, peptide based hydrogelatorsrepresent an extremely interesting class because they can trigger hydrogel formationgiving rise to the formation of biocompatible biomaterials of biological relevance. Forexample, applications include tissue engineering and drug delivery systems. Moreover,self assembling peptides could be used to develop injectable devices.Recently, relevant research efforts are being made in the field of biofabrication ofsuch self-assembling biomaterials. In particular, different classes of enzymes can be usedto trigger the formation of peptidic bonds between precursors that form peptidichydrogelators. Several enzymes derived from GRAS microorganisms can be employed tocatalyze this reaction in aqueous medium, avoiding the use of organic solvents. Suchnovel, "green" synthetic procedures could have a strong impact on peptide production byintroducing milder reaction conditions and limiting the use of harmful chemicals. © 2012 by Nova Science Publishers, Inc. All rights reserved
Supercritical fluid extraction of pharmaceutic compounds from waste materials derived from vinification processes
No full textGrape cultivation dates back to approximately 6000-8000 years ago. Nowadays it is still one of the major crops produced worldwide, mostly for wine production.
Accordingly, grape pomace, the solid remain of the wine making process, is produced in large quantities. The disposal of such waste material is an issue of great ecologic and economic importance. Some wineries use the material as a fertilizer, while others are selling it to biogas companies for energy production. However, grape pomace possesses a much higher potential.
Pomace is composed of grape seeds, stems, pulps and skins and contains pharmaceutically interesting polyphenolic compounds such as catechin, epicatechin, trans-resveratrol and procyanidin B1. Such compounds have beneficial effects on human health including antioxidant, anti-inflammatory, antidiabetic and anticarcinogenic activities.
Such interesting compounds may be extracted from grape pomace by the use of organic solvents, however this procedure has several limitations, including solvent toxicity and the non-selectivity of the extraction towards lipophilic compounds. Alternative extraction technologies focus on the use of supercritical fluids. Supercritical CO2 is the most commonly used solvent, since it is non-toxic, inert and has modest critical values in terms of temperature and pressure, making its use industrially appealing. By the use of supercritical fluids extraction, high-quality extracts can be obtained from a variety of raw materials, including grapes, grape seeds and grape pomace
Progettazione e realizzazione di un innovativo reattore microfluidico capillare per la sintesi di nanoparticelle polimeriche
No full textIl settore delle nanotecnologie ha conosciuto negli ultimi anni una rapida espansione, grazie al forte interesse suscitato dai materiali nanostrutturati in molti settori della ricerca sia di base che applicata, dovuto alle peculiari proprietà chimico-fisiche della materia su scala nanometrica.
Attualmente uno dei problemi maggiori nei procedimenti di sintesi in fase liquida di materiali nanostrutturati in sistemi in bulk è quello relativo al controllo delle dimensioni e del grado di polidispersione delle nanoparticelle ottenute che, unito alla difficoltà di standardizzazione delle condizioni chimico-fisiche di reazione, limita il trasferimento su larga scala di tali tecnologie. L’impiego di reattori mircrofluidici in flusso rappresenta un’alternativa particolarmente interessante per la sintesi di nanomateriali [1]. I principali vantaggi di tale approccio metodologico sono legati alla possibilità di utilizzare volumi molto ridotti di reagenti che ne limitano il costo e l’eventuale tossicità. L’elevato rapporto superficie/volume dei microreattori incrementa gli scambi energetici (es. calore) e il trasferimento di massa rispetto ai reattori convenzionali in bulk. Inoltre i microreattori realizzano un’efficiente miscelazione dei reagenti, che è un elemento fondamentale per l’ottenimento di nanoparticelle monodisperse, incrementando inoltre la possibilità di realizzare reattori, quali ad es. i lab-on-chip, in cui si realizzano contemporaneamente analisi, reazione e purificazione del nanomateriale ottenuto [2].
Il presente studio ha avuto come obiettivo la costruzione ed ottimizzazione dei parametri operativi di un innovativo microreattore modulare a flusso capillare, con modalità flow-focusing, per la sintesi di nanoparticelle biopolimeriche a base di PLGA (acido poli lattico-co-glicolico). Il microreattore capillare deriva dall’assemblaggio di un sistema di tubi capillari in acciao di diametro micrometrico in grado di realizzare una geometria reattoristica con focalizzazione di flusso. L’utilizzo di pompe a siringa provvede al mantenimento dei flussi nel microreattore in un range da 1-3000 ±1 μl/min. Le velocità dei flussi in gioco sono comprese tra 0.1 e 1020 mm/sec, garantendo la realizzazione di condizioni di moto di flusso laminare e bassi valori del numero di Reynolds. Il meccanismo che regola la formazione di nanoparticelle è quello della nanoprecipitazione, che prevede il rapido mescolamento di una soluzione organica del polimero (fase dispersa) con un suo non solvente, generalmente acqua (fase continua), e la successiva precipitazione in quest’ultima del polimero.
In questo lavoro sono stati individuati ed ottimizzati i principali parametri chimico-fisici che controllano la sintesi delle nanoparticelle polimeriche nel reattore microfluidico: il rapporto tra i flussi della fasa continua e della fase dispersa, la concentrazione della soluzione polimerica e le dimensioni del canale di focalizzazione. In seguito all’ottimizzazione di tali parametri operativi, è stato possibile sintetizzare nanoparticelle di PLGA di 20 nm e basso indice di polidispersione.
[1] Zheng B, Tice JD, Roach LS, Ismagilov RF. Angew. Chemie 2004, 116, 2562-2565.
[2] Zao CX, He L, Qiao SZ, Middelberg APJ. Chemical Engineering Science 2011, 66, 1463-1479
Hybrid Systems Biomolecule-Polymeric Nanoparticle: Synthesis, Properties and Biotechnological Applications
No full textThe role of nanomaterials and nanotechnology in life sciences is yet to be fully understood, as it has resulted in the constantly developing field of nanobiotechnology. In fact, nanomaterials can interact with biomacromolecules as well as with living systems and these interactions can be used to develop new materials and technologies which are foreseen to revolutionize our understanding of biological phenomena. This chapter deals with the synthesis of biologically functionalized nanoparticles and their interface properties as well as with their innovative applications, in particular in the biomedical field, in imaging and therapy
A modular microfluidic platform for the synthesis of biopolymeric nanoparticles entrapping organic actives
No full textMicroreactors have been shown to be a powerful tool for the production of nanoparticles (NPs); however, there is still a lack of understanding of the role that the microfluidic environment plays in directing the nanoprecipitation process and the synthetized nanoparticles size and morphology. We fabricated a novel capillary microfluidic device using a newly designed modular apparatus by assembling commercial stainless steel microcapillary tubes for HPLC through a cross junction. In this way, we realized a flow-focusing-based microdevice in which the dispersed organic phase is continuously focused by the continuous phase using a couple of syringe pumps. Our device is substantially distinct from others because of its modularity and flexibility, having the possibility to allocate, in its geometry, microchannels of different length, material, or internal diameter; moreover, it could be used to prepare NPs from different classes of pristine polymers independently from their nature (natural or synthetic ones), and no limitation can be envisaged due to the hydrophobic and hydrophilic character of the applied polymers. Using this capillary microfluidic flow-focusing device we fabricated monodisperse fluorescent-loaded nanoparticles from biodegradable polymers (i.e., poly-lactic-co-glycolic-acid and chitosan) with a one-step procedure. A flourescent probe (6 - coumarin) was incorporated within the biodegradable matrix of the particles. Various operating conditions, such as the polymer molecular weight and concentration, flow rate ratio, type of solvent phase, τmix, microreactor-focusing channel diameters and length, and temperature have been investigated. Their influences on the formation of NPs, have been correlated to the final particle size distribution, ranging from 20 to 300 nm, and morphological characteristics. NPs’ characterization was performed by Dynamic light scattering (DLS), size and Z-potential, and by means scanning electron microscopy (SEM), morphology. This technique allows the fast, low cost, easy, and automated synthesis of polymeric nanoparticles and it may become a useful approach in the progression from laboratory scale to pilot-line scale processes. The presence of the fluorescent probe enables to carry out preliminary studies of cellular uptake, transport and translocation of nanoparticles in cell cultures and in vivo systhems, in order to produce NPs containing organic actives for medical applications and ''plant medicine''. In the future, we will approach fluid dynamics and modeling studies to analyze the microfluidic behavior and mixing process within the capillary microchannels. These results may expand the current understanding of the nanoprecipitation mechanism of biopolymeric NPs and the role exerted by the microfluidic environment
A modular microfluidic platform for the synthesis of biopolymeric nanoparticles entrapping organic actives
No full textBy using a novel and versatile capillary microfluidic flow-focusing device we fabricated monodisperse drug-loaded nanoparticles from biodegradable polymers. A model amphiphilic drug (dexamethasone) was incorporated within the biodegradable matrix of the particles. The effects of flow rate ratio, polymer concentration and microreactor focusing channel dimensions on nanoparticles size and drug loading have been investigated. The presented data demonstrate that the microfluidic approach resulted in the production of colloidal nanoparticles with a narrow size distribution and useful morphological characteristics.This approach allows the rapid, easy, low cost and automated synthesis of polymeric nanoparticles, thus it may become a useful approach in the progression from laboratory scale to pilot-line scale processes
Positively charged biopolymeric nanoparticles for the inhibition of Pseudomonas aeruginosa biofilms
No full textCurrently, many microbial infections have the potential to become lethal owing to the development of antimicrobial resistance by means of different mechanisms and mainly on the basis of the fact that many drugs are unable to reach therapeutic levels in the target sites. This requires the use of high doses and frequent administrations, causing adverse side effects or in some cases toxicity. The use of nanoparticle systems could help to overcome such problems and increase drug efficacy.
In the present study we developed a new drug delivery system based on the use of biopolymeric nanovectors loaded with Tobramycin (Tb), which is the standard antibiotic for the treatment of CF-associated P. aeruginosa lung infections. Tb-loaded biopolymeric nanoparticles composed by dextran sulphate (DS) and chitosan (CS) were prepared by ionotropic gelation. We optimized drug entrapment in DS/CS nanoparticles, obtaining particles of 170 nm and with a drug loading of 400 μg Tb/mg of nanoparticles. In accord with in vitro release experiments such preparations were able to release approximately 25% of their cargo in 60 hours. In vitro antimicrobial efficacy of the drug delivery system on P. aeruginosa biofilm was tested and compared to the effects of free drug revealing that this formulation can reduce the viability of P. aeruginosa biofilms for 48 hours with a single-dose administration
PLGA-based nanoparticles: Effect of chitosan in the aggregate stabilization. A dielectric relaxation spectroscopy study
No full textChitosan-modified polylactic-co-glycolic acid (PLGA) nanoparticles with average diameter of 200 nm in PBS buffer solution have been investigated by means of dielectric relaxation spectroscopy measurements in the frequency range (1 MHz-2 GHz) where interfacial polarizations occur. PLGA-based nanoparticles offer remarkable advantages in different biotechnological fields, such as their biocompatibility, easiness of administration and rather complete biodegradation. However, despite the use of these drug delivery systems is increasing, little is known about the basic process involved in the formation of complexes and in the subsequent release kinetics. In the present work, we have characterized the colloidal behavior of PLGA-based nanoparticles in the presence of oppositely charged chitosan polyelectrolyte by means of dynamic light scattering, electrophoretic mobility and radiowave dielectric relaxation measurements. In particular, we have emphasized how the presence of a coating layer at the nanoparticle surface could exert a marked slowing-down in the drug release. The consequence of this finding is briefly discussed at the light of some biological implications. (C) 2012 Elsevier B.V. All rights reserved
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