1,721,119 research outputs found
Visiting Scientist for a 9-month period at the Center for Biofilm Engineering, Bozeman, Montana, USA
No full textAt the Center for Biofilm Engineering, Dr. Iolanda Francolini worked on a project regrading the development of polymer systems for drug controlled release to prevent medical device-related infections. Particularly, a novel drug delivery polymer matrix consisting of a poly 2-hydroxyethyl methacrylate (pHEMA) hydrogel coated with ordered methylene chains forming an ultrasound-responsive coating was developed. This system was able to retain the loaded drug ciprofloxacin inside the polymer in the absence of ultrasound but showed a significant drug release when low intensity ultrasound was applied. The activity of the developed system to control infectious biofilms was assessed by monitoring the accumulation of Pseudomonas aeruginosa biofilms grown on hydrogels with or without ciprofloxacin and with or without exposure to ultrasound (43 kHz ultrasonic bath for 20 min daily) in an in vitro flow-cell study. The results obtained in this research period were object of two publications on peer-reviewed journals
Prevention and control of biofilm-based medical-device-related infections
No full textBiofilms play a pivotal role in healthcare-associated infections, especially those related to the implant of medical devices, such as intravascular catheters, urinary catheters and orthopaedic implants. This paper reviews the most successful approaches for the control and prevention of these infections as well as promising perspectives for the development of novel devices refractory to microbial adhesion, colonization and biofilm formation
Novel strategies to prevent and control biofilm growth on central venous catheters
No full textIn last decades, several strategies based on antiadhesive, antiseptic or antibiotic coating of polymers have been developed to prevent biofilm formation on the outer and inner surfaces of medical devices. However, the so far developed medicated devices are able to delay microbial colonization in spite of definitively solving the problem of biofilm formation and related infections. In fact, these devices mainly suffer from a relatively short persistence of antimicrobial action as consequence of an early and rapid drug release.
In the last years, we focused our research efforts in developing different experimental approaches to prevent microbial colonization of central venous catheters based on the adsorption of antimicrobial agents to synthesized and properly functionalized polyurethanes with the aim to control drug adsorption and release.
The new antibiofilm strategies we are dealing with concern: i) the development of antimicrobial polymers by the use of polyurethanes able to coordinate metal ions (Ag+, Zn2+, etc); ii) the exploiting of the biofilm matrix-degrading enzyme, DispersinB, to enhance the penetration of antibiotics through the biofilm; iii) the set up of a magnetic nanoparticles (MNPs)-based targeting system to fight in situ catheter-related infections.
As the metal ion-containing polymers are concerned, a carboxylated polyetherurethane (PEUA) was treated with silver, copper, zinc, aluminium and iron salts, thus obtaining PEUA-Ag, PEUA-Cu, PEUA-Zn, PEUA-Al and PEUA-Fe. A part from PEUA-Al, all polymers showed significant antimicrobial properties. The most active was PEUA-Ag which resulted to be able to inhibit S. epidermidis biofilm formation up to 16 days.
As the Dispersin B is concerned, we carried out collaborative experiments with Jeff Kaplan group to evaluate the antibiofilm activity of this β-N-acetylglucosaminidase once adsorbed to our polyurethanes, either alone or in combination with antibiotics.
Finally, we are currently developing a strategy to fight in situ biofilm development by the use of antibiotic loaded-MNPs to be intravenously injected in at risk patients and driven to the device implantation areas by the application of an external magnetic field. This approach will allow an in situ, on demand treatment of biofilm infections. Drugs are expected be released only in the close surroundings of the colonized device and when clinically required. If the planned experiments in animals will be successful, patients could be treated either immediately after the device implant or later in presence of signs of infection
Preparazione di superfici polimeriche antibatteriche per la prevenzione di infezioni catetere-correlate
No full textIl presente lavoro ha avuto lo scopo di adsorbire due antibiotici, il cefamandolo nafato (beta-lattamico) e la vancomicina (glicopepetidico), su materiali maggiormente utilizzati nella realizzazione di catateri quali i poliuretani segmentati. I polimeri sintetizzati sono stati caratterizzati sia sotto il profilo chimico-fisico (misure termiche e meccaniche) che biologico (valutazione dell'attività antimicrobica tramite test di Kirby Bauer)
Funzionalizzazione e caratterizzazione chimico-fisica di matrici polimeriche a carattere anfifilico
No full textPolimeri amfifilici sono stati ottenuto per funzionalizzazione di un polimero commerciale, l'etilen vinil alcol 40/40. In particolare i gruppi alcolici del polimero sono stati funzionalizzati rispettivamente con capriloilcloruro, lauroilcloruro e stearilcloruro, per introdurre catene idrofobiche a diversa lunghezza. I polimeri ottenuti sono stati caratterizzati mediante analisi termica e prove di rigonfiamento in acqua. I supporti sviluppati possono essere sviluppati per l'immobilizzazione di enzimi ad interesse industriale
NOVEL STRATEGIES TO CONTROL BIOFILM FORMATION ON MEDICAL DEVICES.
No full textDevice coating with antimicrobial agents able to inhibit microbial colonisation and biofilm formation represents a pivotal approach in the prevention of medical device-associated infections. Existing antiseptic or antibiotic loaded devices mainly suffer from a relatively short persistence of antimicrobial action as consequence of an early and rapid drug release. On the other hand, the most frequently implicated bugs in device colonisation, such as Staphylococcus, Pseudomonas and Candida spp, are known to develop a largely increased antibiotic resistance due to their sessile mode of growth to form a biofilm. These issues are both critical for the management of patients in clinical settings and need the development of innovative and safer medical devices refractory to microbial adhesion and biofilm formation.
To this aim, we designed and tested in vitro experimental models based on the adsorption on functionalised polymers of: i) a water-insoluble antibiotic active at device level and not used for systemic therapy; ii) pore-former molecules able to modulate drug loading and release; iii) transition metal ions able to synergistically act together with antibiotics.
In particular, we developed new drug-releasing polyurethanes loaded with: i) usnic acid as a water-insoluble drug able to exert antibiofilm activity against Gram-positives and to interfere with quorum-sensing phenomena in Gram-negatives; ii) albumin and polyethylene glycol as porogens promoting the release of rifampin, cefamandole nafate and fluconazole from polyurethanes; iii) silver ions and ciprofloxacin exhibiting a long-lasting antibacterial synergistic activity against Gram-positives and Gram-negatives.
Combined entrapping within our functionalised polyurethanes of antibiotic/antifungal drugs and transition metal ions, when needed in conjunction with porogens as drug release modulators, seem to offer promising strategies both in prevention of bacterial colonisation and biofilm formation and control of drug resistance
Sintesi e caratterizzazione di matrici polimeriche contenenti una combinazione di antibiotici
No full textL’insorgenza di infezioni rappresenta una seria complicanza associata all'impiego di dispositivi medici impiantabili. La nostra ricerca è focalizzata sulla messa a punto di polimeri antibatterici in grado di prevenire la colonizzazione microbica a seguito di adsorbimento chimico di antibiotici sulla loro superficie. Gli esperimenti sono stati condotti su poliuretani, polimeri tra i più impiegati nella fabbricazione dei cateteri. Gli antibiotici cefamandolo e rifampicina nei confronti dei gram-positivi e per la capacità di interagire con i poliuretani. Gli antibiotici sono stati oltre che adsorbiti anche intrappolati nella matrice polimerica sfruttando l'uso di porogeni a diverso peso molecolare al fine di migliorarne il rilascio e la durata antibatterica
Low level laser therapy as an antimicrobial and anti-biofilm technology and its relevance to wound healing
No full textThe biostimulative effect of low-level laser therapy (LLLT) in tissues has been noted in reference to the treatment of various diseases but little information exists on its effectiveness on chronic wounds and biofilm. The scope of this review was to identify literature reporting on LLLT alone, without photodynamic agents, as an antimicrobial/antibiofilm technology and determine its effects on wound healing. Overall the beneficial effects of LLLT in promoting wound healing in animal and human studies has been demonstrated. However, the lack of credible studies using reproducible models and light dosimetry restricts the analysis of current data. Efforts must be addressed to standardize phototherapy procedures as well as to develop suitable in vitro and in vivo biofilm models to test LLLT efficacy in promoting biofilm eradication and wound healing
Selected short papers from SIB-GIB 2003 Italian National Congress - Preparation and characterisation of nanostructured drug release systems
No full textno abstrac
Preparazione e caratterizzazione di sistemi micro e nanostrutturati a rilascio di farmaci
No full textNegli ultimi anni, l'impiego di micro e nanoparticelle biodegradabili per il rilascio di farmaci è risultato un approccio importante per controllare il rilascio sia in termini di cinetica che in termini di sito-specificità. Nel presente lavoro sono state realizzate nanoparticelle di albumina e poliallilammina che sono state poi impiegate per l'intrappolamento di un antibiotico, il cefamandolo nafato. Sistemi nanostrutturati sono stati poi ottenuti per intrappolamento delle particelle ottenute in film di poliuretani. Tale strategia ha permesso di ottenere sistemi a rilascio controllato di farmaco dotati di attività antibatterica duratura nel tempo
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