Silvia Pisani
@sanmatteo.org/site
Otolaryngology Department
IRCCS Fondazione Policlinico San Matteo
RESEARCH INTERESTS
Tissue Engineering
Drug Delivery Systems
Scopus Publications
Scopus Publications
Giulia M Di Gravina, Elia Bari, Stefania Croce, Franca Scocozza, Silvia Pisani, Bice Conti, Maria A Avanzini, Ferdinando Auricchio, Lorenzo Cobianchi, Maria Luisa Torre,et al.
IOP Publishing
Abstract Bioprinting offers new opportunities to obtain reliable 3D in vitro models of the liver for testing new drugs and studying pathophysiological mechanisms, thanks to its main feature in controlling the spatial deposition of cell-laden hydrogels. In this context, decellularized extracellular matrix (dECM)-based hydrogels have caught more and more attention over the last years because of their characteristic to closely mimic the tissue-specific microenvironment from a biological point of view. In this work, we describe a new concept of designing dECM-based hydrogels; in particular, we set up an alternative and more practical protocol to develop a hepatic lyophilized dECM (lyo-dECM) powder as an ‘off-the-shelf’ and free soluble product to be incorporated as a biomimetic component in the design of 3D-printable hybrid hydrogels. To this aim, the powder was first characterized in terms of cytocompatibility on human and porcine mesenchymal stem cells (MSCs), and the optimal powder concentration (i.e. 3.75 mg ml−1) to use in the hydrogel formulation was identified. Moreover, its non-immunogenicity and capacity to reactivate the elastase enzyme potency was proved. Afterward, as a proof-of-concept, the powder was added to a sodium alginate/gelatin blend, and the so-defined multi-component hydrogel was studied from a rheological point of view, demonstrating that adding the lyo-dECM powder at the selected concentration did not alter the viscoelastic properties of the original material. Then, a printing assessment was performed with the support of computational simulations, which were useful to define a priori the hydrogel printing parameters as window of printability and its post-printing mechanical collapse. Finally, the proposed multi-component hydrogel was bioprinted with cells inside, and its post-printing cell viability for up to 7 d was successfully demonstrated.
Mariella Rosalia, Martina Giacomini, Erika Maria Tottoli, Rossella Dorati, Giovanna Bruni, Ida Genta, Enrica Chiesa, Silvia Pisani, Maurilio Sampaolesi, and Bice Conti
MDPI AG
The design, production, and characterisation of tissue-engineered scaffolds made of polylactic-co-glycolic acid (PLGA), polycaprolactone (PCL) and their blends obtained through electrospinning (ES) or solvent casting/particulate leaching (SC) manufacturing techniques are presented here. The polymer blend composition was chosen to always obtain a prevalence of one of the two polymers, in order to investigate the contribution of the less concentrated polymer on the scaffolds’ properties. Physical–chemical characterization of ES scaffolds demonstrated that tailoring of fibre diameter and Young modulus (YM) was possible by controlling PCL concentration in PLGA-based blends, increasing the fibre diameter from 0.6 to 1.0 µm and reducing the YM from about 22 to 9 MPa. SC scaffolds showed a “bubble-like” topography, caused by the porogen spherical particles, which is responsible for decreasing the contact angles from about 110° in ES scaffolds to about 74° in SC specimens. Nevertheless, due to phase separation within the blend, solvent-casted samples displayed less reproducible properties. Furthermore, ES samples were characterised by 10-fold higher water uptake than SC scaffolds. The scaffolds suitability as iPSCs culturing support was evaluated using XTT assay, and pluripotency and integrin gene expression were investigated using RT-PCR and RT-qPCR. Thanks to their higher wettability and appropriate YM, SC scaffolds seemed to be superior in ensuring high cell viability over 5 days, whereas the ability to maintain iPSCs pluripotency status was found to be similar for ES and SC scaffolds.
Erika Maria Tottoli, Laura Benedetti, Federica Riva, Enrica Chiesa, Silvia Pisani, Giovanna Bruni, Ida Genta, Bice Conti, Gabriele Ceccarelli, and Rossella Dorati
MDPI AG
Hypertrophic scars (HTSs) are pathological structures resulting from chronic inflammation during the wound healing process, particularly in complex injuries like burns. The aim of this work is to propose Biofiber PF (biodegradable fiber loaded with Pirfenidone 1.5 w/w), an electrospun advanced dressing, as a solution for HTSs treatment in complex wounds. Biofiber has a 3-day antifibrotic action to modulate the fibrotic process and enhance physiological healing. Its electrospun structure consists of regular well-interconnected Poly-L-lactide-co-poly-ε-caprolactone (PLA-PCL) fibers (size 2.83 ± 0.46 µm) loaded with Pirfenidone (PF, 1.5% w/w), an antifibrotic agent. The textured matrix promotes the exudate balance through mild hydrophobic wettability behavior (109.3 ± 2.3°), and an appropriate equilibrium between the absorbency % (610.2 ± 171.54%) and the moisture vapor transmission rate (0.027 ± 0.036 g/min). Through its finer mechanical properties, Biofiber PF is conformable to the wound area, promoting movement and tissue oxygenation. These features also enhance the excellent elongation (>500%) and tenacity, both in dry and wet conditions. The ancillary antifibrotic action of PF on hypertrophic scar fibroblast (HSF) for 3 days downregulates the cell proliferation over time and modulates the gene expression of transforming growth factor β1 (TGF-β1) and α-smooth muscle actin (α-SMA) at 48–72 h. After 6 days of treatment, a decrement of α-SMA protein levels was detected, proving the potential of biofiber as a valid therapeutic treatment for HTSs in an established wound healing process.
Silvia Pisani, Valeria Mauri, Erika Negrello, Valeria Friuli, Ida Genta, Rossella Dorati, Giovanna Bruni, Stefania Marconi, Ferdinando Auricchio, Andrea Pietrabissa,et al.
MDPI AG
Background: To make the regenerative process more effective and efficient, tissue engineering (TE) strategies have been implemented. Three-dimensional scaffolds (electrospun or 3D-printed), due to their suitable designed architecture, offer the proper location of the position of cells, as well as cell adhesion and the deposition of the extracellular matrix. Moreover, the possibility to guarantee a concomitant release of drugs can promote tissue regeneration. Methods: A PLA/PCL copolymer was used for the manufacturing of electrospun and hybrid scaffolds (composed of a 3D-printed support coated with electrospun fibers). Dexamethasone was loaded as an anti-inflammatory drug into the electrospun fibers, and the drug release kinetics and scaffold biological behavior were evaluated. Results: The encapsulation efficiency (EE%) was higher than 80%. DXM embedding into the electrospun fibers resulted in a slowed drug release rate, and a slower release was seen in the hybrid scaffolds. The fibers maintained their nanometric dimensions (less than 800 nm) even after deposition on the 3D-printed supports. Cell adhesion and proliferation was favored in the DXM-loading hybrid scaffolds. Conclusions: The hybrid scaffolds that were developed in this study can be optimized as a versatile platform for soft tissue regeneration.
Silvia Pisani, Deborah Di Martino, Silvia Cerri, Ida Genta, Rossella Dorati, Giulia Bertino, Marco Benazzo, and Bice Conti
MDPI AG
In this work, four different active encapsulation methods, microfluidic (MF), sonication (SC), freeze–thawing (FT), and electroporation (EP), were investigated to load a model protein (bovine serum albumin—BSA) into neutral liposomes made from 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC):cholesterol (Chol) and charged liposomes made from DSPC:Chol:Dioleoyl-3-trimethylammonium propane (DOTAP), DSPC:Chol:1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS), and DSPC:Chol:phosphatidylethanolamine (PE). The aim was to increase the protein encapsulation efficiency (EE%) by keeping the liposome size below 200 nm and the PDI value below 0.7, which warrants a nearly monodisperse preparation. Electroporation (100 V) yielded the best results in terms of EE%, with a dramatic increase in liposome size (>600 nm). The FT active-loading method, either applied to neutral or charged liposomes, allowed for obtaining suitable EE%, keeping the liposome size range below 200 nm with a suitable PDI index. Cationic liposomes (DSPC:Chol:DOTAP) loaded with the FT active method showed the best results in terms of EE% (7.2 ± 0.8%) and size (131.2 ± 11.4 nm, 0.140 PDI). In vitro release of BSA from AM neutral and charged liposomes resulted slower compared to PM liposomes and was affected by incubation temperature (37 °C, 4 °C). The empty charged liposomes tested for cell viability on Human Normal Dermal Fibroblast (HNDF) confirmed their cytocompatibility also at high concentrations (1010 particles/mL) and cellular uptake at 4 °C and 37 °C. It can be concluded that even if both microfluidic passive and active methods are more easily transferable to an industrial scale, the FT active-loading method turned out to be the best in terms of BSA encapsulation efficiencies, keeping liposome size below 200 nm.
Mariella Rosalia, Pietro Grisoli, Rossella Dorati, Enrica Chiesa, Silvia Pisani, Giovanna Bruni, Ida Genta, and Bice Conti
MDPI AG
Vascular graft infections are a severe complication in vascular surgery, with a high morbidity and mortality. Prevention and treatment involve the use of antibiotic- or antiseptic-impregnated artificial vascular grafts, but currently, there are no commercially available infection-proof small-diameter vascular grafts (SDVGs). In this work we investigated the antimicrobic activity of two SDVGs prototypes loaded with tobramycin and produced via the electrospinning of drug-doped PLGA (polylactide-co-glycolide) solutions. Differences in rheological and conductivity properties of the polymer solutions resulted in non-identical fibre morphology that deeply influenced the hydration profile and consequently the in vitro cumulative drug release, which was investigated by using a spectrofluorimetric technique. Using DDSolver Excel add-in, modelling of the drug release kinetic was performed to evaluate the release mechanism involved: Prototype 1 showed a sustained and diffusive driven drug release, which allowed for the complete elution of tobramycin within 2 weeks, whereas Prototype 2 resulted in a more extended drug release controlled by both diffusion and matrix relaxation. Time-kill assays performed on S. aureus and E. coli highlighted the influence of burst drug release on the decay rate of bacterial populations, with Prototype 1 being more efficient on both microorganisms. Nevertheless, both prototypes showed good antimicrobic activity over the 5 days of in vitro testing.
Erika M. Tottoli, Laura Benedetti, Enrica Chiesa, Silvia Pisani, Giovanna Bruni, Ida Genta, Bice Conti, Gabriele Ceccarelli, and Rossella Dorati
MDPI AG
Hypertrophic scars (HTSs) are aberrant structures that develop where skin is injured complexly and represent the result of a chronic inflammation as a healing response. To date, there is no satisfactory prevention option for HTSs, which is due to the complexity of multiple mechanisms behind the formation of these structures. The present work aimed to propose Biofiber (Biodegradable fiber), an advanced textured electrospun dressing, as a suitable solution for HTS formation in complex wounds. Biofiber has been designed as a 3-day long-term treatment to protect the healing environment and enhance wound care practices. Its textured matrix consists of homogeneous and well-interconnected Poly-L-lactide-co-poly-ε-caprolactone (PLA-PCL) electrospun fibers (size 3.825 ± 1.12 µm) loaded with Naringin (NG, 2.0% w/w), a natural antifibrotic agent. The structural units contribute to achieve an optimal fluid handling capacity demonstrated through a moderate hydrophobic wettability behavior (109.3 ± 2.3°), and a suitable balance between absorbency (389.8 ± 58.16%) and moisture vapor transmission rate (MVTR, 2645 ± 60.43 g/m2 day). The flexibility and conformability of Biofiber to the body surfaces is due to its innovative circular texture, that also allow it to obtain finer mechanical properties after 72 h in contact with Simulated Wound Fluid (SWF), with an elongation of 352.6 ± 36.10%, and a great tenacity (0.25 ± 0.03 Mpa). The ancillary action of NG results in a prolonged anti-fibrotic effect on Normal Human Dermal Fibroblasts (NHDF), through the controlled release of NG for 3 days. The prophylactic action was highlighted at day 3 with the down regulation of the major factors involved in the fibrotic process: Transforming Growth Factor β1 (TGF-β1), Collagen Type 1 alpha 1 chain (COL1A1), and α-smooth muscle actin (α-SMA). No significant anti-fibrotic effect has been demonstrated on Hypertrophic Human Fibroblasts derived from scars (HSF), proving the potential of Biofiber to minimize HTSs in the process of early wound healing as a prophylactic therapy.
Silvia Pisani, Ida Genta, Tiziana Modena, Rossella Dorati, Giovanna Bruni, Marco Benazzo, and Bice Conti
Springer Science and Business Media LLC
Abstract This study is a proof of concept performed to evaluate process parameters affecting shape memory effect of copolymer poly-l-lactide-co-poly-ε-caprolactone (PLA:PCL) 70:30 ratio based nanofibrous scaffolds. A design of experiment (DOE) statistical approach was used to define the interaction between independent material and process variables related to electrospun scaffold manufacturing, such as polymer solution concentration (w/v%), spinning time (min), and needle size (Gauge), and their influence on Rf% (ability of the scaffold to maintain the induced temporary shape) and Rr% (ability of the scaffold to recover its original shape) outputs. A mathematical model was obtained from DOE useful to predict scaffold Rf% and Rr% values. PLA-PCL 15% w/v, 22G needle, and 20-min spinning time were selected to confirm the data obtained from theoretical model. Subsequent morphological (SEM), chemical-physical (GPC and DSC), mechanical (uniaxial tensile tests), and biological (cell viability and adhesion) characterizations were performed. Graphical abstract
Silvia Pisani, Valeria Mauri, Erika Negrello, Simone Mauramati, Gianluca Alaimo, Ferdinando Auricchio, Marco Benazzo, Rossella Dorati, Ida Genta, Bice Conti,et al.
Frontiers Media SA
Introduction: The problem of organs’ shortage for transplantation is widely known: different manufacturing techniques such as Solvent casting, Electrospinning and 3D Printing were considered to produce bioartificial scaffolds for tissue engineering purposes and possible transplantation substitutes. The advantages of manufacturing techniques’ combination to develop hybrid scaffolds with increased performing properties was also evaluated.Methods: Scaffolds were produced using poly-L-lactide-co-caprolactone (PLA-PCL) copolymer and characterized for their morphological, biological, and mechanical features.Results: Hybrid scaffolds showed the best properties in terms of viability (>100%) and cell adhesion. Furthermore, their mechanical properties were found to be comparable with the reference values for soft tissues (range 1–10 MPa).Discussion: The created hybrid scaffolds pave the way for the future development of more complex systems capable of supporting, from a morphological, mechanical, and biological standpoint, the physiological needs of the tissues/organs to be transplanted.
Doretta Capsoni, Paola Lucini, Debora Maria Conti, Michela Bianchi, Federica Maraschi, Beatrice De Felice, Giovanna Bruni, Maryam Abdolrahimi, Davide Peddis, Marco Parolini,et al.
MDPI AG
The present work aimed at decorating halloysite nanotubes (HNT) with magnetic Fe3O4 nanoparticles through different synthetic routes (co-precipitation, hydrothermal, and sol-gel) to test the efficiency of three magnetic composites (HNT/Fe3O4) to remove the antibiotic ofloxacin (OFL) from waters. The chemical–physical features of the obtained materials were characterized through the application of diverse techniques (XRPD, FT-IR spectroscopy, SEM, EDS, and TEM microscopy, thermogravimetric analysis, and magnetization measurements), while ecotoxicity was assessed through a standard test on the freshwater organism Daphnia magna. Independently of the synthesis procedure, the magnetic composites were successfully obtained. The Fe3O4 is nanometric (about 10 nm) and the weight percentage is sample-dependent. It decorates the HNT’s surface and also forms aggregates linking the nanotubes in Fe3O4-rich samples. Thermodynamic and kinetic experiments showed different adsorption capacities of OFL, ranging from 23 to 45 mg g−1. The kinetic process occurred within a few minutes, independently of the composite. The capability of the three HNT/Fe3O4 in removing the OFL was confirmed under realistic conditions, when OFL was added to tap, river, and effluent waters at µg L−1 concentration. No acute toxicity of the composites was observed on freshwater organisms. Despite the good results obtained for all the composites, the sample by co-precipitation is the most performant as it: (i) is easily magnetically separated from the media after the use; (ii) does not undergo any degradation after three adsorption cycles; (iii) is synthetized through a low-cost procedure. These features make this material an excellent candidate for removal of OFL from water.
Mariella Rosalia, Enrica Chiesa, Erika Maria Tottoli, Rossella Dorati, Ida Genta, Bice Conti, and Silvia Pisani
MDPI AG
Nowadays, antimicrobial resistance (AMR) represents a challenge for antibiotic therapy, mostly involving Gram-negative bacteria. Among the strategies activated to overcome AMR, the repurposing of already available antimicrobial molecules by encapsulating them in drug delivery systems, such as nanoparticles (NPs) and also engineered NPs, seems to be promising. Tobramycin is a powerful and effective aminoglycoside, approved for complicated infections and reinfections and indicated mainly against Gram-negative bacteria, such as Pseudomonas aeruginosa, Escherichia coli, Proteus, Klebsiella, Enterobacter, Serratia, Providencia, and Citrobacter species. However, the drug presents several side effects, mostly due to dose frequency, and for this reason, it is a good candidate for nanomedicine formulation. This review paper is focused on what has been conducted in the last 20 years for the development of Tobramycin nanosized delivery systems (nanoantibiotics), with critical discussion and comparison. Tobramycin was selected as the antimicrobial drug because it is a wide-spectrum antibiotic that is effective against both Gram-positive and Gram-negative aerobic bacteria, and it is characterized by a fast bactericidal effect, even against multidrug-resistant microorganisms (MDR).
Silvia Pisani, Giulia Bertino, Adriele Prina-Mello, Laura Deborah Locati, Simone Mauramati, Ida Genta, Rossella Dorati, Bice Conti, and Marco Benazzo
MDPI AG
Squamous cell carcinoma is the most common malignancy that arises in the head-and-neck district. Traditional treatment could be insufficient in case of recurrent and/or metastatic cancers; for this reason, more selective and enhanced treatments are in evaluation in preclinical and clinical trials to increase in situ concentration of chemotherapy drugs promoting a selectively antineoplastic activity. Among all cancer treatment types (i.e., surgery, chemotherapy, radiotherapy), electroporation (EP) has emerged as a safe, less invasive, and effective approach for cancer treatment. Reversible EP, using an intensive electric stimulus (i.e., 1000 V/cm) applied for a short time (i.e., 100 μs), determines a localized electric field that temporarily permealizes the tumor cell membranes while maintaining high cell viability, promoting cytoplasm cell uptake of antineoplastic agents such as bleomycin and cisplatin (electrochemotherapy), calcium (Ca2+ electroporation), siRNA and plasmid DNA (gene electroporation). The higher intracellular concentration of antineoplastic agents enhances the antineoplastic activity and promotes controlled tumor cell death (apoptosis). As secondary effects, localized EP (i) reduces the capillary blood flow in tumor tissue (“vascular lock”), lowering drug washout, and (ii) stimulates the immune system acting against cancer cells. After years of preclinical development, electrochemotherapy (ECT), in combination with bleomycin or cisplatin, is currently one of the most effective treatments used for cutaneous metastases and primary skin and mucosal cancers that are not amenable to surgery. To reach this clinical evidence, in vitro and in vivo models were preclinically developed for evaluating the efficacy and safety of ECT on different tumor cell lines and animal models to optimize dose and administration routes of drugs, duration, and intensity of the electric field. Improvements in reversible EP efficacy are under evaluation for HNSCC treatment, where the focus is on the development of a combination treatment between EP-enhanced nanotechnology and immunotherapy strategies.
Erika Maria Tottoli, Enrica Chiesa, Gabriele Ceccarelli, Silvia Pisani, Giovanna Bruni, Ida Genta, Bice Conti, and Rossella Dorati
Elsevier BV
Silvia Pisani, Enrica Chiesa, Ida Genta, Rossella Dorati, Marilena Gregorini, Maria Antonietta Grignano, Marina Ramus, Gabriele Ceccarelli, Stefania Croce, Chiara Valsecchi,et al.
MDPI AG
This work focuses on formulating liposomes to be used in isolated kidney dynamic machine perfusion in hypothermic conditions as drug delivery systems to improve preservation of transplantable organs. The need mainly arises from use of kidneys from marginal donors for transplantation that are more exposed to ischemic/reperfusion injury compared to those from standard donors. Two liposome preparation techniques, thin film hydration and microfluidic techniques, are explored for formulating liposomes loaded with two model proteins, myoglobin and bovine serum albumin. The protein-loaded liposomes are characterized for their size by DLS and morphology by TEM. Protein releases from the liposomes are tested in PERF-GEN perfusion fluid, 4 °C, and compared to the in vitro protein release in PBS, 37 °C. Fluorescent liposome uptake is analyzed by fluorescent microscope in vitro on epithelial tubular renal cell cultures and ex vivo on isolated pig kidney in hypothermic perfusion conditions. The results show that microfluidics are a superior technique for obtaining reproducible spherical liposomes with suitable size below 200 nm. Protein encapsulation efficiency is affected by its molecular weight and isoelectric point. Lowering incubation temperature slows down the proteins release; the perfusion fluid significantly affects the release of proteins sensitive to ionic media (such as BSA). Liposomes are taken up by epithelial tubular renal cells in two hours’ incubation time.
Valeria Friuli, Silvia Pisani, Bice Conti, Giovanna Bruni, and Lauretta Maggi
MDPI AG
A challenge in the pharmaceutical sector is the development of controlled release dosage forms for oral administration of poorly soluble drugs, in particular, drugs characterized by pH-dependent solubility through the gastrointestinal tract, which itself shows wide variability in terms of environmental pHs. The best approach is to increase the dissolution rate of the drugs at the different pHs and only then modify its release behavior from the pharmaceutical form. This work aims to demonstrate the ability of properly designed polymeric nanofibers in enhancing the release rate of model drugs with different pH-dependent solubility in the different physiological pHs of the gastrointestinal tract. Polymeric nanofibers loaded with meloxicam and carvedilol were prepared using the electrospinning technique and were then included in properly designed tablet formulations to obtain fast or sustained release dosage forms. The nanofibers and the tablets were characterized for their morphological, physico-chemical and dissolution properties. The tablets are able to deliver the dose according to the expected release behavior, and zero-order, first-order, Higuchi, Korsmeyer–Peppas and Hixon–Crowell kinetics models were used to analyze the prevailing release mechanism of the tablets. This study shows that the electrospun fibers can be advantageously included in oral dosage forms to improve their release performances.
Silvia Pisani, Valeria Calcaterra, Stefania Croce, Rossella Dorati, Giovanna Bruni, Ida Genta, Antonia Avanzini, Marco Benazzo, Gloria Pelizzo, and Bice Conti
Elsevier BV
Silvia Pisani, Ida Genta, Tiziana Modena, Rossella Dorati, Marco Benazzo, and Bice Conti
MDPI AG
Shape-Memory Polymers (SMPs) are considered a kind of smart material able to modify size, shape, stiffness and strain in response to different external (heat, electric and magnetic field, water or light) stimuli including the physiologic ones such as pH, body temperature and ions concentration. The ability of SMPs is to memorize their original shape before triggered exposure and after deformation, in the absence of the stimulus, and to recover their original shape without any help. SMPs nanofibers (SMPNs) have been increasingly investigated for biomedical applications due to nanofiber’s favorable properties such as high surface area per volume unit, high porosity, small diameter, low density, desirable fiber orientation and nanoarchitecture mimicking native Extra Cellular Matrix (ECM). This review focuses on the main properties of SMPs, their classification and shape-memory effects. Moreover, advantages in the use of SMPNs and different biomedical application fields are reported and discussed.
Silvia Pisani, Stefania Croce, Simone Mauramati, Marta Marmonti, Lorenzo Cobianchi, Irene Herman, Rossella Dorati, Maria Antonietta Avanzini, Ida Genta, Marco Benazzo,et al.
MDPI AG
Acquired congenital esophageal malformations, such as malignant esophageal cancer, require esophagectomy resulting in full thickness resection, which cannot be left untreated. The proposed approach is a polymeric full-thickness scaffold engineered with mesenchymal stem cells (MSCs) to promote and speed up the regeneration process, ensuring adequate support and esophageal tissue reconstruction and avoiding the use of autologous conduits. Copolymers poly-L-lactide-co-poly-ε-caprolactone (PLA-PCL) 70:30 and 85:15 ratio were chosen to prepare electrospun tubular scaffolds. Electrospinning apparatus equipped with two different types of tubular mandrels: cylindrical (∅ 10 mm) and asymmetrical (∅ 10 mm and ∅ 8 mm) were used. Tubular scaffolds underwent morphological, mechanical (uniaxial tensile stress) and biological (MTT and Dapi staining) characterization. Asymmetric tubular geometry resulted in the best properties and was selected for in vivo surgical implantation. Anesthetized pigs underwent full thickness circumferential resection of the mid-lower thoracic esophagus, followed by implantation of the asymmetric scaffold. Preliminary in vivo results demonstrated that detached stitch suture achieved better results in terms of animal welfare and scaffold integration; thus, it is to be preferred to continuous suture.
Silvia Pisani, Ida Genta, Rossella Dorati, Tiziana Modena, Enrica Chiesa, Giovanna Bruni, Marco Benazzo, and Bice Conti
Elsevier BV
Silvia Pisani, Valeria Friuli, Bice Conti, Giovanna Bruni, and Lauretta Maggi
Elsevier BV
Rossella Dorati, Enrica Chiesa, Mariella Rosalia, Silvia Pisani, Ida Genta, Giovanna Bruni, Tiziana Modena, and Bice Conti
MDPI AG
This work aimed at formulating tubular grafts electrospun with a size < 6 mm and incorporating vancomycin as an antimicrobial agent. Compared to other papers, the present study succeeded in using medical healthcare-grade polymers and solvents permitted by ICH Topic Q3C (R4). Vancomycin (VMC) was incorporated into polyester synthetic polymers (poly-L-lactide-co-poly-ε-caprolactone and poly lactide-co-glycolide) using permitted solvents; moreover, a surfactant was added to the formulation in order to avoid the precipitation of VMC on fiber surface. A preliminary preformulation study was carried out to evaluate solubility of VMC in different aqueous and organic solvents and its stability. To reduce size of fibers and their orientation, we studied a solvent system based on methylene chloride and acetone (DCM/acetone), at different ratios (80:20, 70:30, and 60:40). Considering conductivity of solutions and their spinnability, solvent system at a 80:20 ratio was selected for the study. SEM images demonstrated that size of fibers, their distribution, and their orientation were affected by the incorporation of VMC and surfactant into polymer solution. Surfactant allowed for the reduction of precipitates of VMC on fiber surface, which are responsible of the high burst release in the first six hours; the release was mainly dependent on graft structure porosity, number of pores, and graft absorbent capability. A controlled release of VMC was achieved, covering a period from 96 to 168 h as a function of composition and structure; the concentration of VMC was significantly beyond VMC minimum inhibitory concentration (MIC, 2 ug/mL). These results indicated that the VMC tubular electrospun grafts not only controlled the local release of VMC, but also avoided onset of antibiotic resistance.
Silvia Pisani, Rossella Dorati, Ida Genta, Marco Benazzo, Bice Conti, and Adriele Prina Mello
Elsevier BV
Rossella Dorati, Silvia Pisani, Enrica Chiesa, Ida Genta, Giovanna Bruni, Tiziana Modena, and Bice Conti
Elsevier BV
Silvia Pisani, Ida Genta, Rossella Dorati, Paraskevi Kavatzikidou, Despoina Angelaki, Aleka Manousaki, Kanelina Karali, Anthi Ranella, Emmanuel Stratakis, and Bice Conti
Wiley
Silvia Pisani, Rossella Dorati, Franca Scocozza, Camilla Mariotti, Enrica Chiesa, Giovanna Bruni, Ida Genta, Ferdinando Auricchio, Michele Conti, and Bice Conti
Wiley
The study aims to investigate a novel bioink made from Chitosan (Cs)/ poly(gamma-glutamic acid) (Gamma-PGA) hydrogel that takes advantage of the two biodegradable and biocompatible polymers meeting most of the requirements for biomedical applications. The bioink could be an alternative to other materials commonly used in 3D-bioprinting such as gelatin or alginate. Cs/ Gamma-PGA hydrogel was prepared by double extrusion of Gamma-PGA and Cs solutions, where 2 × 105 human adult fibroblasts per ml Cs solution had been loaded, through Cellink 3D-Bioprinter at 37°C. A computer aided design model was used to get 3D-bioprinting of a four layers grid hydrogel construct with 70% infill. Hydrogel characterization involved rheology, FTIR analysis, stability study (mass loss [ML], fluid uptake [FU]), and cell retaining ability into hydrogel. 3D-bioprinted hydrogel gelation time resulted to be <60 s, hydrogel structure was maintained up to 36.79 Pa shear stress, FTIR analysis demonstrated Gamma-PGA/Cs interpolyelectrolyte complex formation. The 3D-bioprinted hydrogel was stable for 35 days (35% ML) in cell culture medium, with increasing FU. Cell loaded 3D-bioprinted Cs 6% hydrogel was able to retain 70% of cells which survived to printing process and cell viability was maintained during 14 days incubation.