Publications by authors named "Paola Petrini"

30 Publications

  • Page 1 of 1

Engineered modular microphysiological models of the human airway clearance phenomena.

Biotechnol Bioeng 2021 Jun 18. Epub 2021 Jun 18.

Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy.

Mucociliary clearance is a crucial mechanism that supports the elimination of inhaled particles, bacteria, pollution, and hazardous agents from the human airways, and it also limits the diffusion of aerosolized drugs into the airway epithelium. In spite of its relevance, few in vitro models sufficiently address the cumulative effect of the steric and interactive barrier function of mucus on the one hand, and the dynamic mucus transport imposed by ciliary mucus propulsion on the other hand. Here, ad hoc mucus models of physiological and pathological mucus are combined with magnetic artificial cilia to model mucociliary transport in both physiological and pathological states. The modular concept adopted in this study enables the development of mucociliary clearance models with high versatility since these can be easily modified to reproduce phenomena characteristic of healthy and diseased human airways while allowing to determine the effect of each parameter and/or structure separately on the overall mucociliary transport. These modular airway models can be available off-the-shelf because they are exclusively made of readily available materials, thus ensuring reproducibility across different laboratories.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/bit.27866DOI Listing
June 2021

Technological tools and strategies for culturing human gut microbiota in engineered in vitro models.

Biotechnol Bioeng 2021 Aug 24;118(8):2886-2905. Epub 2021 May 24.

Department of Chemistry, Materials and Chemical Engineering "Giulio Natta," Politecnico di Milano, Milan, Italy.

The gut microbiota directly impacts the pathophysiology of different human body districts. Consequently, microbiota investigation is an hot topic of research and its in vitro culture has gained extreme interest in different fields. However, the high sensitivity of microbiota to external stimuli, such as sampling procedure, and the physicochemical complexity of the gut environment make its in vitro culture a challenging task. New engineered microfluidic gut-on-a-chip devices have the potential to model some important features of the intestinal structure, but they are usually unable to sustain culture of microbiota over an extended period of time. The integration of gut-on-a-chip devices with bioreactors for continuous bacterial culture would lead to fast advances in the study of microbiota-host crosstalk. In this review, we summarize the main technologies for the continuous culture of microbiota as upstream systems to be coupled with microfluidic devices to study bacteria-host cells communication. The engineering of integrated microfluidic platforms, capable of sustaining both anaerobic and aerobic cultures, would be the starting point to unveil complex biological phenomena proper of the microbiota-host crosstalks, paving to way to multiple research and technological applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/bit.27816DOI Listing
August 2021

The Open Challenge of Modeling Complex and Multi-Microbial Communities in Three-Dimensional Niches.

Front Bioeng Biotechnol 2020 20;8:539319. Epub 2020 Oct 20.

Department of Chemistry, Materials and Chemical Engineering "Giulio Natta" and UdR INSTM Politecnico di Milano, Milan, Italy.

The comprehension of the underlying mechanisms of the interactions within microbial communities represents a major challenge to be faced to control their outcome. Joint efforts of , and ecological models are crucial to controlling human health, including chronic infections. In a broader perspective, considering that polymicrobial communities are ubiquitous in nature, the understanding of these mechanisms is the groundwork to control and modulate bacterial response to any environmental condition. The reduction of the complex nature of communities of microorganisms to a single bacterial strain could not suffice to recapitulate the situation observed in mammals. Furthermore, some bacteria can adapt to various physiological or arduous environments embedding themselves in three-dimensional matrices, secluding from the external environment. Considering the increasing awareness that dynamic complex and dynamic population of microorganisms (microbiota), inhabiting different apparatuses, regulate different health states and protect against pathogen infections in a fragile and dynamic equilibrium, we underline the need to produce models to mimic the three-dimensional niches in which bacteria, and microorganisms in general, self-organize within a microbial consortium, strive and compete. This review mainly focuses, as a case study, to lung pathology-related dysbiosis and life-threatening diseases such as cystic fibrosis and bronchiectasis, where the co-presence of different bacteria and the altered 3D-environment, can be considered as worst-cases for chronic polymicrobial infections. We illustrate the state-of-art strategies used to study biofilms and bacterial niches in chronic infections, and multispecies ecological competition. Although far from the rendering of the 3D-environments and the polymicrobial nature of the infections, they represent the starting point to face their complexity. The increase of knowledge respect to the above aspects could positively affect the actual healthcare scenario. Indeed, infections are becoming a serious threat, due to the increasing bacterial resistance and the slow release of novel antibiotics on the market.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fbioe.2020.539319DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7606986PMC
October 2020

From tissue engineering to engineering tissues: the role and application of models.

Biomater Sci 2021 Jan;9(1):70-83

Department of Chemistry, Materials and Chemical Engineering "Giulio Natta"- Politecnico di Milano, Italy.

Engineered models have emerged as relevant in vitro tools to foresee the translational potential of new therapies from the bench to the bedside in a fast and cost-effective fashion. The principles applied to the development of tissue-engineered constructs bring the foundation concepts to engineer relevant in vitro models. Engineered models often face scepticism, because regularly these do not include the extreme complexity of nature, but rather a simplification of a phenomenon. While engineering in vitro models, a hypothesis is imposed towards which defined parameters are included to assess the degree of similarity between the in vitro model and the native phenomenon, keeping in mind their intrinsic limitations. The development of in vitro models has been highly supported and disseminated by different regulatory agencies. This review aims at defining and exploring the multifaceted potential of tangible, not theoretical, models within the biomedical field to represent physiological tissues and organ-related phenomena.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0bm01097aDOI Listing
January 2021

Shear-resistant hydrogels to control permeability of porous tubular scaffolds in vascular tissue engineering.

Mater Sci Eng C Mater Biol Appl 2019 Dec 30;105:110035. Epub 2019 Jul 30.

Dipartimento di Chimica, Materiali e Ingegneria Chimica, 'G. Natta' Politecnico di Milano, Piazza L. da Vinci, Milano, Italy.

Aiming to perfuse porous tubular scaffolds for vascular tissue engineering (VTE) with controlled flow rate, prevention of leakage through the scaffold lumen is required. A gel coating made of 8% w/v alginate and 6% w/v gelatin functionalized with fibronectin was produced using a custom-made bioreactor-based method. Different volumetric proportions of alginate and gelatin were tested (50/50, 70/30, and 90/10). Gel swelling and stability, and rheological, and uniaxial tensile tests reveal superior resistance to the aggressive biochemical microenvironment, and their ability to withstand physiological deformations (~10%) and wall shear stresses (5-20 dyne/cm). These are prerequisites to maintain the physiologic phenotypes of vascular smooth muscle cells and endothelial cells (ECs), mimicking blood vessels microenvironment. Gels can induce ECs proliferation and colonization, especially in the presence of fibronectin and higher percentages of gelatin. The custom-designed bioreactor enables the development of reproducible and homogeneous tubular gel coating. The permeability tests show the effectiveness of tubular scaffolds coated with 70/30 alginate/gelatin gel to occlude wadding pores, and therefore prevent leakages. The synthesized double-layered tubular scaffolds coated with alginate/gelatin gel and fibronectin represent both promising substrate for ECs and effective leakproof scaffolds, when subjected to pulsatile perfusion, for VTE applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2019.110035DOI Listing
December 2019

Disassembling the complexity of mucus barriers to develop a fast screening tool for early drug discovery.

J Mater Chem B 2019 08;7(32):4940-4952

Department of Chemistry, Materials and Chemical Engineering "Giulio Natta" at Politecnico di Milano, Milan, Italy.

Mucus is a natural barrier with a protective role that hinders drug diffusion, representing a steric and interactive barrier to overcome for an effective drug delivery to target sites. In diseases like cystic fibrosis (CF), pulmonary mucus exhibits altered features, which hamper clearance mechanisms and drug diffusion, ultimately leading to lung failure. Effectively modelling the passage through mucus still represents an unmet challenge. An airway CF mucus model is herein proposed to disassemble the complexity of the mucus barrier following a modular approach. A hydrogel, mainly composed of mucin in an alginate (Alg) network, is proposed to specifically model the chemical-physical properties of CF mucus. The steric retention of pathological mucus was reproduced by targeting its mesh size (approximately 50 nm) and viscoelastic properties. The interactive barrier was reproduced by a composition inspired from the CF mucus. Optimized mucus models, composed of 3 mg ml-1 Alg and 25 mg ml-1 mucin, exhibited a G' increasing from ∼21.2 to 55.2 Pa and a G'' ranging from ∼5.26 to 28.8 Pa in the frequency range of 0.1 to 20 Hz. Drug diffusion was tested using three model drugs. The proposed mucus model was able to discriminate between the mucin-drug interaction and the steric barrier of a mucus layer with respect to the parallel artificial membrane permeability (PAMPA) that models the phospholipidic cell membrane, the state-of-the-art screening tool for passive drug diffusion. The mucus model can be proposed as an in vitro tool for early drug discovery, representing a step forward to model the mucus layer. Additionally, the proposed methodology allows to easily include other molecules present within mucus, as relevant proteins, lipids and DNA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9tb00957dDOI Listing
August 2019

Mucin binding to therapeutic molecules: The case of antimicrobial agents used in cystic fibrosis.

Int J Pharm 2019 Jun 13;564:136-144. Epub 2019 Apr 13.

Molecular Biotechnology and Health Science Department, University of Torino, Via Gioachino Quarello 15, 10135 Torino, Italy. Electronic address:

Mucin is a complex glycoprotein consisting of a wide variety of functional groups that can interact with exogenous agents. The binding to mucin plays a crucial role in drug pharmacokinetics especially in diseases, such as cystic fibrosis (CF), where mucin is overexpressed. In this study, we have investigated the interaction between mucin and several drugs used in CF therapy. Protein-drug interaction was carried out by UV-Vis and fluorescence spectroscopy; quenching mechanism, binding constants, number of binding sites, thermodynamic parameters and binding distance of the interaction were obtained.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijpharm.2019.04.032DOI Listing
June 2019

Encapsulated functionalized stereocomplex PLA particles: An effective system to support mucolytic enzymes.

Colloids Surf B Biointerfaces 2019 Jul 1;179:190-198. Epub 2019 Apr 1.

Department of Chemistry and Industrial Chemistry, University of Genoa, Via Dodecaneso 31, 16146, Genoa, Italy. Electronic address:

In this work, the preparation of a novel enzyme carrier based on a polymer multicomponent system was assessed. Indeed, the design of the above system considered several issues that are the need of applying a biodegradable polymer carrier, characterized by a nanometric dimension, thus suitable to diffuse into the dense mucus structure, with functionalities capable of interacting/reacting with enzymes but resistant to enzymatic degradation. The particles were prepared from solutions containing equimolar amount of high-molecular-weight poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) and by applying the nanoprecipitation method. Dynamic Light Scattering (DLS) measurements allowed to establish the optimal preparation conditions to obtain polymer particles characterized by diameters lower than 1 μm, which dimensions were confirmed by Field Emission Scanning Electron Microscope (FE-SEM) analysis. In order to produce surface functionalization, necessary for anchoring enzymes, the stereocomplexed particles, whose structuration was confirmed by Differential Scanning Calorimetry (DSC) measurements, underwent an amminolysis reaction by using a diamine as reactant. The treated particles were characterized by means of FE-SEM, Fourier-Transform Infrared Spectroscopy (FTIR), DLS and zeta potential measurements and their characteristics were compared with those of the neat PLLA/PDLA particles. The degree of functionalization turned out to depend on the applied conditions, it increasing by enhancing the reaction time. The activity of enzymes, i.e. papain and alginate lyase, anchored to the particles, was evaluated by Quartz Crystal Microbalance (QCM) and UV measurements. Moreover, with the aim at exploiting the material for an inhalation administration, a method to encapsulate the enzyme-particles systems was assessed. Conversely to free enzymes, the developed systems were found to be capable of diminishing the viscosity of two hydrogels, ad hoc prepared and based on the main constituents of the real mucus.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.colsurfb.2019.03.071DOI Listing
July 2019

Polysaccharide-based hydrogels with tunable composition as 3D cell culture systems.

Int J Artif Organs 2018 Apr 19;41(4):213-222. Epub 2018 Feb 19.

1 Department of Chemistry, Materials and Chemical Engineering, Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Milan, Italy.

Background: To date, cell cultures have been created either on 2-dimensional (2D) polystyrene surfaces or in 3-dimensional (3D) systems, which do not offer a controlled chemical composition, and which lack the soft environment encountered in vivo and the chemical stimuli that promote cell proliferation and allow complex cellular behavior. In this study, pectin-based hydrogels were developed and are proposed as versatile cell culture systems.

Methods: Pectin-based hydrogels were produced by internally crosslinking pectin with calcium carbonate at different initial pH, aiming to control crosslinking kinetics and degree. Additionally, glucose and glutamine were added as additives, and their effects on the viscoelastic properties of the hydrogels and on cell viability were investigated.

Results: Pectin hydrogels showed in high cell viability and shear-thinning behavior. Independently of hydrogel composition, an initial swelling was observed, followed by a low percentage of weight variation and a steady-state stage. The addition of glucose and glutamine to pectin-based hydrogels rendered higher cell viability up to 90%-98% after 1 hour of incubation, and these hydrogels were maintained for up to 7 days of culture, yet no effect on viscoelastic properties was detected.

Conclusions: Pectin-based hydrogels that offer tunable composition were developed successfully. They are envisioned as synthetic extracellular matrix (ECM) either to study complex cellular behaviors or to be applied as tissue engineering substitutes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5301/ijao.5000667DOI Listing
April 2018

Immunological and Differentiation Properties of Amniotic Cells Are Retained After Immobilization in Pectin Gel.

Cell Transplant 2018 01;27(1):70-76

1 Centro di Ricerca "E. Menni," Fondazione Poliambulanza Istituto Ospedaliero, Brescia, Italy.

Mesenchymal stromal cells from the human amniotic membrane (i.e., human amniotic mesenchymal stromal cells [hAMSCs]) of term placenta are increasingly attracting attention for their applications in regenerative medicine. Osteochondral defects represent a major clinical problem with lifelong chronic pain and compromised quality of life. Great promise for osteochondral regeneration is held in hydrogel-based constructs that have a flexible composition and mimic the physiological structure of cartilage. Cell loading within a hydrogel represents an advantage for regenerative purposes, but the encapsulation steps can modify cell properties. As pectin gels have also been explored as cell vehicles on 3D scaffolds, the aim of this study was to explore the possibility to include hAMSCs in pectin gel. Immobilization of hAMSCs into pectin gels could expand their application in cell-based bioengineering strategies. hAMSCs were analyzed for their viability and recovery from the pectin gel and for their ability to differentiate toward the osteogenic lineage and to maintain their immunological characteristics. When treated with a purposely designed pectin/hydroxyapatite gel biocomposite, hAMSCs retained their ability to differentiate toward the osteogenic lineage, did not induce an immune response, and retained their ability to reduce T cell proliferation. Taken together, these results suggest that hAMSCs could be used in combination to pectin gels for the study of novel osteochondral regeneration strategies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0963689717738786DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6434488PMC
January 2018

Stereocomplex poly(lactic acid) nanocoated chitosan microparticles for the sustained release of hydrophilic drugs.

Mater Sci Eng C Mater Biol Appl 2017 Jul 22;76:1129-1135. Epub 2017 Mar 22.

Department of Chemistry and Industrial Chemistry, University of Genoa, Genoa, Italy.

In this work, novel chitosan based microparticles were developed by the layer-by-layer deposition of poly(lactic acid) stereocomplex films on their surface in the view of controlling the release of encapsulated hydrophilic drugs. As first step, the quartz crystal microbalance technique was used to monitor the step-by-step deposition of the stereocomplex layers onto chitosan by evaluating the deposited mass for each layer. Chitosan microparticles, with a size ranging between 40 and 90μm, were then produced by an aerodynamically-assisted jetting technique and covered by a poly(lactic acid) stereocomplex shell. Infrared spectroscopy, wide X-ray diffraction, field emission scanning electron microscopy and contact angle measurements were used to verify the effective poly(lactic acid) adsorption onto chitosan microparticles and the stereocomplex formation. Finally, the release of a hydrophilic local anesthetic, procaine hydrochloride, from uncoated and stereocomplex-nanocoated microparticles was preliminary evaluated over a period of 15days.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2017.03.170DOI Listing
July 2017

Nanostructured polysaccharidic microcapsules for intracellular release of cisplatin.

Int J Biol Macromol 2017 Jun 20;99:187-195. Epub 2017 Feb 20.

Biological and Environmental Sciences and Technology Department, University of Salento, & UdR INSTM di Lecce-Campus Universitario, via Monteroni, 73100 Lecce, Italy; Istituto di Nanotecnologia (CNR-NANOTEC) University of Salento, Via Monteroni, 73100 Lecce, Italy. Electronic address:

Carbohydrate polimeric microcapsules were assembled using a LbL approach onto a CaCO core. The microcapsules were used to delivery the anticancer drug cisplatin into HeLa and MCF-7 cancer cell lines. Drug encapsulation, measured by ICP spectroscopy, was around 50% of the charging solution. Fluorimetric measurements showed an efficient cellular uptake of polysacchardic microcapsules in both cell lines. The drug-loaded capsules demonstrated a better efficiency against cell viability than the free drug. Specifically, the amount of platinum reaching genomic DNA was measured, showing that encapsulation improves the nuclear delivery of the drug for both cell lines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijbiomac.2017.02.066DOI Listing
June 2017

From micro- to nanostructured implantable device for local anesthetic delivery.

Int J Nanomedicine 2016 8;11:2695-709. Epub 2016 Jun 8.

Department of Chemistry, Materials and Chemical Engineering 'G. Natta', Politecnico di Milano, Milan, Italy.

Local anesthetics block the transmission of painful stimuli to the brain by acting on ion channels of nociceptor fibers, and find application in the management of acute and chronic pain. Despite the key role they play in modern medicine, their cardio and neurotoxicity (together with their short half-life) stress the need for developing implantable devices for tailored local drug release, with the aim of counterbalancing their side effects and prolonging their pharmacological activity. This review discusses the evolution of the physical forms of local anesthetic delivery systems during the past decades. Depending on the use of different biocompatible materials (degradable polyesters, thermosensitive hydrogels, and liposomes and hydrogels from natural polymers) and manufacturing processes, these systems can be classified as films or micro- or nanostructured devices. We analyze and summarize the production techniques according to this classification, focusing on their relative advantages and disadvantages. The most relevant trend reported in this work highlights the effort of moving from microstructured to nanostructured systems, with the aim of reaching a scale comparable to the biological environment. Improved intracellular penetration compared to microstructured systems, indeed, provides specific drug absorption into the targeted tissue and can lead to an enhancement of its bioavailability and retention time. Nanostructured systems are realized by the modification of existing manufacturing processes (interfacial deposition and nanoprecipitation for degradable polyester particles and high- or low-temperature homogenization for liposomes) or development of novel strategies (electrospun matrices and nanogels). The high surface-to-volume ratio that characterizes nanostructured devices often leads to a burst drug release. This drawback needs to be addressed to fully exploit the advantage of the interaction between the target tissues and the drug: possible strategies could involve specific binding between the drug and the material chosen for the device, and a multiscale approach to reach a tailored, prolonged drug release.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2147/IJN.S99028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4907738PMC
December 2016

Correction: Biofunctionalized pectin hydrogels as 3D cellular microenvironments.

J Mater Chem B 2015 Nov 2;3(42):8422. Epub 2015 Oct 2.

INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua do Campo Alegre no 823, 4150-180 Porto, Portugal.

Correction for 'Biofunctionalized pectin hydrogels as 3D cellular microenvironments' by Sara C. Neves et al., J. Mater. Chem. B, 2015, 3, 2096-2108.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c5tb90139aDOI Listing
November 2015

Biofunctionalized pectin hydrogels as 3D cellular microenvironments.

J Mater Chem B 2015 Mar 4;3(10):2096-2108. Epub 2015 Feb 4.

INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua do Campo Alegre no 823, 4150-180 Porto, Portugal.

In situ-forming hydrogels of pectin, a polysaccharide present in the cell wall of higher plants, were prepared using an internal ionotropic gelation strategy based on calcium carbonate/d-glucono-δ-lactone, and explored for the first time as cell delivery vehicles. Since no ultrapure pectins are commercially available yet, a simple and efficient purification method was established, effectively reducing the levels of proteins, polyphenols and endotoxins of the raw pectin. The purified pectin was then functionalized by carbodiimide chemistry with a cell-adhesive peptide (RGD). Its gelation was analyzed by rheometry and optimized. Human mesenchymal stem cells embedded within unmodified and RGD-pectin hydrogels of different viscoelasticities (1.5 and 2.5 wt%) remained viable and metabolically active for up to 14 days. On unmodified pectin hydrogels, cells remained isolated and round-shaped. In contrast, within RGD-pectin hydrogels they elongated, spread, established cell-to-cell contacts, produced extracellular matrix, and migrated outwards the hydrogels. After 7 days of subcutaneous implantation in mice, acellular pectin hydrogels were considerably degraded, particularly the 1.5 wt% hydrogels. Altogether, these findings show the great potential of pectin-based hydrogels, which combine an interesting set of easily tunable properties, including the in vivo degradation profile, for tissue engineering and regenerative medicine.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c4tb00885eDOI Listing
March 2015

Cross-linked poly(acrylic acids) microgels and agarose as semi-interpenetrating networks for resveratrol release.

J Mater Sci Mater Med 2015 Jan 11;26(1):5328. Epub 2015 Jan 11.

Department of Chemistry, Materials and Chemical Engineering "G.Natta" and Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Milan, Italy,

Carbomers, cross-linked poly(acrylic acid) microgels, have been widely used in pharmaceutical formulations as swollen hydrogels. Agarose, whose thermoreversibility may be exploited for drug loading, forms a gel with a mechanism involving coil-helix transition at about 36 °C. In this work carbomer microgels were combined with agarose networks in a semi-interpenetrating polymer network structure, aiming at obtaining suitable delivery systems for the loading and release of molecules with poor bioavailability but high therapeutic interest, like resveratrol. The rheological properties of the formulations and their in vitro cytocompatibility were studied and optimized acting on the neutralizing agent (triethylamine (N,N-diethylethanamine), triethanolamine (tris(2-hydroxyethyl)amine) and sodium hydroxide) and amount of OH donors (1,2-propanediol and glycerol). As a preparation method, autoclaving was introduced to simultaneously obtain heating and sterilising. Among the different neutralizing agents, NaOH was chosen to avoid the use of amines, considering the final application. Without the addition of alcohols as typical OH donors to induce Carbomer gelification, gels with appropriate rheological properties and stability were produced. For this formulation, the release of resveratrol after 7 days was about 80 % of the loaded mass, suggesting it is an interesting approach to be exploited for the development of innovative resveratrol delivery systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10856-014-5328-8DOI Listing
January 2015

Reactive hydroxyapatite fillers for pectin biocomposites.

Mater Sci Eng C Mater Biol Appl 2014 Dec 9;45:154-61. Epub 2014 Sep 9.

Laboratorio di Biomateriali, Dipartimento di Chimica, Materiali e Ingegneria Chimica 'G. Natta', Piazza Leonardo da Vinci 32, 20133 Milano, Italy; UdR INSTM Milano Politecnico, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.

In this work, a novel injectable biocomposite hydrogel is produced by internal gelation, using pectin as organic matrix and hydroxyapatite either as crosslinking agent and inorganic reinforcement. Tunable gelling kinetics and rheological properties are obtained varying the hydrogels' composition, with the final aim of developing systems for cell immobilization. The reversibility by dissolution of pectin-hydroxyapatite hydrogels is achieved with saline solutions, to possibly accelerate the release of the cells or active agents immobilized. Texture analysis confirms the possibility of extruding the biocomposites from needles with diameters from 20 G to 30 G, indicating that they can be implanted with minimally-invasive approaches, minimizing the pain during injection and the side effects of the open surgery. L929 fibroblasts entrapped in the hydrogels survive to the immobilization procedure and exhibit high cell viability. On the overall, these systems result to be suitable supports for the immobilization of cells for tissue regeneration applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2014.09.003DOI Listing
December 2014

Pain assessment in animal models: do we need further studies?

J Pain Res 2014 8;7:227-36. Epub 2014 May 8.

University of Pavia, Department of Surgical, Clinical, Paediatric and Diagnostic Science, General Surgery 1, IRCCS Fondazione Policlinico San Matteo, Pavia, Italy.

In the last two decades, animal models have become important tools in understanding and treating pain, and in predicting analgesic efficacy. Although rodent models retain a dominant role in the study of pain mechanisms, large animal models may predict human biology and pharmacology in certain pain conditions more accurately. Taking into consideration the anatomical and physiological characteristics common to man and pigs (median body size, digestive apparatus, number, size, distribution and communication of vessels in dermal skin, epidermal-dermal junctions, the immunoreactivity of peptide nerve fibers, distribution of nociceptive and non-nociceptive fiber classes, and changes in axonal excitability), swines seem to provide the most suitable animal model for pain assessment. Locomotor function, clinical signs, and measurements (respiratory rate, heart rate, blood pressure, temperature, electromyography), behavior (bright/quiet, alert, responsive, depressed, unresponsive), plasma concentration of substance P and cortisol, vocalization, lameness, and axon reflex vasodilatation by laser Doppler imaging have been used to assess pain, but none of these evaluations have proved entirely satisfactory. It is necessary to identify new methods for evaluating pain in large animals (particularly pigs), because of their similarities to humans. This could lead to improved assessment of pain and improved analgesic treatment for both humans and laboratory animals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2147/JPR.S59161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4020878PMC
June 2014

Injectable pectin hydrogels produced by internal gelation: pH dependence of gelling and rheological properties.

Carbohydr Polym 2014 Mar 24;103:339-47. Epub 2013 Dec 24.

Laboratorio di Biomateriali, Dipartimento di Chimica, Materiali e Ingegneria Chimica 'G. Natta' and Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milan, Italy.

The production of injectable pectin hydrogels by internal gelation with calcium carbonate is proposed. The pH of pectin was increased with NaOH or NaHCO3 to reach physiological values. The determination of the equivalence point provided evidence that the pH can be more precisely modulated with NaHCO3 than with NaOH. Degradation and inability to gel was observed for pectin solutions with pH 5.35 or higher. Therefore, pectin solutions with pH values varying from 3.2 (native pH) to 3.8 were chosen to produce the gels. The increase of the pH for the crosslinked hydrogels, as well as the reduction of the gelling time and their thickening, was dependent upon the amount of calcium carbonate, as confirmed by rheology. Hydrogel extracts were not cytotoxic for L-929 fibroblasts. On the overall, the investigated formulations represent interesting injectable systems providing an adequate microenvironment for cell, drug or bioactive molecules delivery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.carbpol.2013.12.057DOI Listing
March 2014

New perspectives in cell delivery systems for tissue regeneration: natural-derived injectable hydrogels.

J Appl Biomater Funct Mater 2012 Sep 27;10(2):67-81. Epub 2012 Sep 27.

Laboratorio di Biomateriali, Bioengineering Department and UdR INSTM Milano Politecnico, Politecnico di Milano, Milano - Italy

.

Natural polymers, because of their biocompatibility, availability, and physico-chemical properties have been the materials of choice for the fabrication of injectable hydrogels for regenerative medicine. In particular, they are appealing materials for delivery systems and provide sustained and controlled release of drugs, proteins, gene, cells, and other active biomolecules immobilized.In this work, the use of hydrogels obtained from natural source polymers as cell delivery systems is discussed. These materials were investigated for the repair of cartilage, bone, adipose tissue, intervertebral disc, neural, and cardiac tissue. Papers from the last ten years were considered, with a particular focus on the advances of the last five years. A critical discussion is centered on new perspectives and challenges in the regeneration of specific tissues, with the aim of highlighting the limits of current systems and possible future advancements.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5301/JABFM.2012.9418DOI Listing
September 2012

Poly(ethylene glycol) and hydroxy functionalized alkane phosphate self-assembled monolayers reduce bacterial adhesion and support osteoblast proliferation.

Int J Artif Organs 2011 Sep;34(9):898-907

Biomaterials Laboratory, Bioengineering Department, Politecnico di Milano, Milan, Italy.

Purpose: Presently there is interest today in designing improved titanium surfaces capable of high bioactivity in order to promote strong anchorage of the bone surrounding implants while at the same time discouraging bioadhesion. Poly(ethylene glycol)-modified (PEG) alkane phosphate and OH-terminated alkane phosphates have been demonstrated to be spontaneously adsorbed onto titanium oxide surfaces and produce surfaces with different protein resistance in relation to the PEG surface density. This study aims to evaluate caries-associated Streptococcus mutans (S. mutans) adhesion and osteoblast proliferation while varying the PEG surface density of titanium surfaces.

Methods: Bacterial adhesion was quantified by fluorescence microscopy and SAOS-2 human osteoblast proliferation was evaluated up to 7 days of culture in vitro. Metabolic activity of osteoblasts was measured by MTT test and the secretion of extracellular matrix proteins (osteopontin, osteocalcin and type I collagen) in culture medium was determined by immunoenzymatic assays.

Results: As the PEG surface density increased, the bacterial adhesion considerably decreased when compared to uncoated titanium surfaces. The monomolecular coatings proved to be capable of supporting osteoblast proliferation with the greatest levels of metabolic activity at the highest PEG surface concentrations.

Conclusions: These results are extremely promising for potential clinical application in implant uses where both reduction of bacteria adhesion and stimulation of bone formation are highly desirable.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5301/ijao.5000047DOI Listing
September 2011

Trends in biomedical engineering: focus on Smart Bio-Materials and Drug Delivery.

J Appl Biomater Biomech 2011 May-Aug;9(2):87-97

Bioengineering Department, Politecnico di Milano, Milano, Italy.

The present article reviews on different research lines, namely: drug and gene delivery, surface modification/modeling, design of advanced materials (shape memory polymers and biodegradable stents), presently developed at Politecnico di Milano, Italy. For gene delivery, non-viral polycationic-branched polyethylenimine (b-PEI) polyplexes are coated with pectin, an anionic polysaccharide, to enhance the polyplex stability and decrease b-PEI cytotoxicity. Perfluorinated materials, specifically perfluoroether, and perfluoro-polyether fluids are proposed as ultrasound contrast agents and smart agents for drug delivery. Non-fouling, self-assembled PEG-based monolayers are developed on titanium surfaces with the aim of drastically reducing cariogenic bacteria adhesion on dental implants. Femtosecond laser microfabrication is used for selectively and spatially tuning the wettability of polymeric biomaterials and the effects of femtosecond laser ablation on the surface properties of polymethylmethacrylate are studied. Innovative functionally graded Alumina-Ti coatings for wear resistant articulating surfaces are deposited with PLD and characterized by means of a combined experimental and computational approach. Protein adsorption on biomaterials surfaces with an unlike wettability and surface-modification induced by pre-adsorbed proteins are studied by atomistic computer simulations. A study was performed on the fabrication of porous Shape Memory Polymeric structures and on the assessment of their potential application in minimally invasive surgical procedures. A model of magnesium (alloys) degradation, in a finite element framework analysis, and a bottom-up multiscale analysis for modeling the degradation mechanism of PLA matrices was developed, with the aim of providing valuable tools for the design of bioresorbable stents.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5301/JABB.2011.8563DOI Listing
March 2013

Trends in biomedical engineering: focus on Regenerative Medicine.

J Appl Biomater Biomech 2011 May-Aug;9(2):73-86

Department of Bioengineering, Politecnico di Milano, Milano, Italy.

Regenerative medicine is a critical frontier in biomedical and clinical research. The major progresses in the last few years were driven by a strong clinical need which could benefit from regenerative medicine outcomes for the treatment of a large number of conditions including birth defects, degenerative and neoplastic diseases, and traumatic injuries. Regenerative medicine applies the principles of engineering and life sciences to enhance the comprehension of the fundamental biological mechanisms underlying the structure-function relationships in physiologic and pathologic tissues and to accomplish alternative strategies for developing in vitro biological substitutes which are able to restore, maintain, or improve tissue, and organ function. This paper reviews selected approaches currently being investigated at Politecnico di Milano in the field of regenerative medicine. Specific tissue-oriented topics are divided in three sections according to each developmental stage: in vitro study, pre-clinical study, and clinical application. In vitro studies investigate the basic phenomena related to gene delivery, stem cell behavior, tissue regeneration, and to explore dynamic culture potentiality in different applications: cardiac and skeletal muscle, cartilage, hematopoietic system, peripheral nerve, and gene delivery. Specific fields of regenerative medicine, i.e., bone, blood vessels, and ligaments engineering have already reached the preclinical stage providing promising insights for further research towards clinical applications. The translation of the results obtained during in vitro and preclinical steps into clinical organ replacement is a very challenging issue, which can offer a valid alternative to fight morbidity, organ shortage, and ethical-social problems associated with allotransplantation as shown in the clinical case reported in this review.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5301/JABB.2011.8562DOI Listing
March 2013

Enzymatic cross-linking of human recombinant elastin (HELP) as biomimetic approach in vascular tissue engineering.

J Mater Sci Mater Med 2011 Dec 13;22(12):2641-50. Epub 2011 Oct 13.

Bioengineering Department, Biomaterials Laboratory, Politecnico di Milano, Milan, Italy.

The use of polymers naturally occurring in the extracellular matrix (ECM) is a promising strategy in regenerative medicine. If compared to natural ECM proteins, proteins obtained by recombinant DNA technology have intrinsic advantages including reproducible macromolecular composition, sequence and molecular mass, and overcoming the potential pathogens transmission related to polymers of animal origin. Among ECM-mimicking materials, the family of recombinant elastin-like polymers is proposed for drug delivery applications and for the repair of damaged elastic tissues. This work aims to evaluate the potentiality of a recombinant human elastin-like polypeptide (HELP) as a base material of cross-linked matrices for regenerative medicine. The cross-linking of HELP was accomplished by the insertion of cross-linking sites, glutamine and lysine, in the recombinant polymer and generating ε-(γ-glutamyl) lysine links through the enzyme transglutaminase. The cross-linking efficacy was estimated by infrared spectroscopy. Freeze-dried cross-linked matrices showed swelling ratios in deionized water (≈2500%) with good structural stability up to 24 h. Mechanical compression tests, performed at 37°C in wet conditions, in a frequency sweep mode, indicated a storage modulus of 2/3 kPa, with no significant changes when increasing number of cycles or frequency. These results demonstrate the possibility to obtain mechanically resistant hydrogels via enzymatic crosslinking of HELP. Cytotoxicity tests of cross-linked HELP were performed with human umbilical vein endothelial cells, by use of transwell filter chambers for 1-7 days, or with its extracts in the opportune culture medium for 24 h. In both cases no cytotoxic effects were observed in comparison with the control cultures. On the whole, the results suggest the potentiality of this genetically engineered HELP for regenerative medicine applications, particularly for vascular tissue regeneration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10856-011-4451-zDOI Listing
December 2011

Fabrication of chemically cross-linked porous gelatin matrices.

J Appl Biomater Biomech 2009 Sep-Dec;7(3):194-9

BioMatLab, Department of Bioengineering, Politecnico di Milano, Milano - Italy.

Purpose: The aim of this study was to chemically cross-link gelatin, by reacting its free amino groups with an aliphatic diisocyanate.

Methods: To produce hydrogels with controllable properties, the number of reacting amino groups was carefully determined. Porosity was introduced into the gelatin-based hydrogels through the lyophilization process. Porous and non-porous matrices were characterized with respect to their chemical structure, morphology, water uptake and mechanical properties.

Results: The physical, chemical and mechanical properties of the porous matrices are related to the extent of their cross-linking, showing that they can be controlled by varying the reaction parameters. Water uptake values (24 hours) vary between 160% and 200% as the degree of cross-linking increases. The flexibility of the samples also decreases by changing the extent of cross-linking. Young's modulus shows values between 0.188 KPa, for the highest degree, and 0.142 KPa for the lowest degree.

Conclusions: The matrices are potential candidates for use as tissue-engineering scaffolds by modulating their physical chemical properties according to the specific application.
View Article and Find Full Text PDF

Download full-text PDF

Source
October 2012

Poly(ethylene glycol) and hydroxy functionalized alkane phosphate mixed self-assembled monolayers to control nonspecific adsorption of proteins on titanium oxide surfaces.

Langmuir 2010 May;26(9):6529-34

BioMatLab, Bioengineering Department, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.

The spontaneous formation of alkane phosphate self-assembled monolayers (SAMs) on titanium oxide was chosen as a tool to tailor the surface physicochemical properties in terms of nonspecific adsorption of proteins. For this aim, poly(ethylene glycol)-modified (PEG) alkane phosphate was codeposited with OH-terminated alkane phosphates. X-ray photoelectron spectroscopy and ellipsometry of the resulting mixed SAMs indicate that the PEG density can be controlled by varying the mole fraction of PEG-terminated phosphates in the solutions used during the deposition process, leading to surfaces with different degrees of protein resistance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/la904066yDOI Listing
May 2010

In vitro interaction of human fibroblasts and platelets with a shape-memory polyurethane.

J Biomed Mater Res A 2005 Apr;73(1):1-11

Biomaterials Laboratory, Bioengineering Department, Politecnico di Milano, P.zza L. da Vinci 32, 20133 Milano, Italy.

Physicochemical and mechanical properties, in vitro cytotoxicity, cytocompatibility, and platelet adhesion were investigated on a shape-memory polyether-based polyurethane (MM-5520 SMPu) using the polyether-based Pellethane 2363-80AE (Pell-2363 SPU) as reference. MM-5520 SMPu and Pell-2363 SPU showed similar average molecular weights and different surface properties, with a higher hydrophilicity and roughness for the SMPu. By tensile tests and dynamic mechanical analysis, the peculiar characteristics of the MM-5520 SMPu were evidenced: strong temperature-dependent behavior for SMPu compared with SPU, and a high shape recovery. MM-5520 SMPu did not show any cytotoxic effect on the adhesion and proliferation of human skin fibroblasts and gingival fibroblasts, and a good cytocompatibility was observed with both cell types, as demonstrated by cell counting and scanning electron microscopy observations. SMPu compared with SPU showed higher adsorption of extracellular matrix proteins such as fibronectin, fibrinogen, and collagens. Proteins adsorbed onto SMPu significantly enhanced the adhesion and proliferation of human fibroblasts. The interaction of SMPu with platelets was studied with platelet rich plasma. Fewer platelets adhered to the SMPu, with minor morphological variations than onto the SPU. The cytocompatibility and hemocompatibility of MM-5520 SMPu combined with its unique properties such as change in shape or in stiffness, depending on practical requirements, make this shape-memory material potentially advantageous for biomedical applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbm.a.30193DOI Listing
April 2005

Silk fibroin-coated three-dimensional polyurethane scaffolds for tissue engineering: interactions with normal human fibroblasts.

Tissue Eng 2003 Dec;9(6):1113-21

Department of Biomedical and Surgical Sciences, University of Verona, Verona, Italy.

Silk fibroin (SF)-based or -coated biomaterials hold structural and surface properties that render them suitable for biomedical applications. In this work, we investigated the behavior of four strains of normal human adult fibroblasts (HAFs) seeded onto polyurethane foam, uncoated (PUF) or SF coated (PUF/SF). HAF adhesion within 3 h to PUF/SF was 2-fold that of adhesion to PUF. After 30 days of incubation in vitro, 37% more HAFs had grown on PUF/SF than on PUF. Taking 10(5) cells as a basis for comparisons, HAFs on PUF/SF exhibited initially higher glucose consumption rates, but persistently lower glutamine uptake rates than on PUF, whereas the rates of lactate and interleukin 6 release and of extracellular assembly of type I collagen fibers were alike on either substrate. Moreover, HAFs on both PUF/SF and PUF never secreted any ELISA-assayable amounts of interleukin 1beta, tumor necrosis factor alpha, and transforming growth factor beta(1). Hence, PUF/SF scaffolds embody a novel class of biomaterials favoring the adhesion, proliferation, and performance of specific metabolic tasks by HAFs without eliciting any concurrent secretion of the chief proinflammatory cytokines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/10763270360728026DOI Listing
December 2003

Silk fibroin/poly(carbonate)-urethane as a substrate for cell growth: in vitro interactions with human cells.

Biomaterials 2003 Feb;24(5):789-99

Department of Biomedical & Surgical Sciences, Histology & Embryology Unit, Verona, Italy.

Silk fibroin (SF)-based or -coated biomaterials are likely to be endowed with structural and surface properties that render them particularly apt for biomedical applications. In this work we investigated the behavior of four different strains of normal human adult fibroblasts that had been seeded onto membranes made up of poly(carbonate) urethane (PCU), the surfaces of which had or had not been homogeneously coated with SF. Cell adhesion within 3h to the SF-coated PCU films was 2.2-fold that to their uncoated homologues. After 30 days of incubation in vitro, 2.5-fold more cells had grown on the SF-coated specimens than on the uncoated ones. This enhanced cell adherence and hence growth on the SF-coated surfaces was coupled with higher cumulative rates of D-glucose (but not L-glutamine) uptake and of both lactate and interleukin-6 (IL-6) cumulative secretion. Conversely, human fibroblasts cultured on either type of PCU scaffolds never secreted any ELISA-assayable amount of three main proinflammatory cytokines, namely interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-beta1 (TGF-beta1). Finally, when the metabolic activities were compared on a per 10(5) cells basis, it became clear that the adhesion to SF favored an initially higher consumption of D-glucose, a late higher release of IL-6, and an at-first more intense, but declining, extracellular assembly of type I collagen fibers. Overall, these results show that SF-coated PCU membranes represent a novel type of biomaterial that favors the adhesion, the growth and performance of specific metabolic tasks by normal human adult fibroblasts without eliciting any concurrent secretion of some of the chief proinflammatory cytokines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/s0142-9612(02)00417-9DOI Listing
February 2003

In vitro interactions of biomedical polyurethanes with macrophages and bacterial cells.

J Biomater Appl 2002 Jan;16(3):191-214

Biochemistry Department, University of Pavia, Italy.

Three commercial medical-grade polyurethanes (PUs), a poly-ether-urethane (Pellethane), and two poly-carbonate-urethanes, the one aromatic (Bionate) and the other aliphatic (Chronoflex), were tested for macrophages and bacterial cells adhesion, in the presence or absence of adhesive plasma proteins. All the experiments were carried out on PUs films obtained by solvent casting. The wettability of these films was analysed by measuring static contact angles against water. The ability of the selected PUs to adsorb human fibronectin (Fn) and fibrinogen (Fbg) was checked by ELISA with biotin-labelled proteins. All PUs were able to adsorb Fn and Fbg (Fn > Fbg). Fn adsorption was in the order: Pellethane > Chronoflex > Bionate, the highest Fbg adsorption being detected onto Bionate (Bionate > Chronoflex > Pellethane). The human macrophagic line J111, and the two main bacterial strains responsible for infection in humans (Staphylococcus aureus Newman and Staphylococcus epidermidis 14852) were incubated in turn with the three PUs, uncoated or coated with plasma proteins. No macrophage or bacterial adhesion was observed onto uncoated PUs. PUs coated with plasma, Fn or Fbg promoted bacterial adhesion (S. aureus > S. epidermidis), whereas macrophage adhered more onto PUs coated with Fn or plasma. The coating with Fbg did not promote cell adhesion. Pellethane showed the highest macrophage activation (i.e. spreading), followed, in the order, by Bionate and Chronoflex.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0885328202016003175DOI Listing
January 2002
-->