iBB

João Carlos Silva was awarded with one of the Education Travel Grants of the Orthoregeneration Network (ON) Foundation to participate and share the latest developments of his research work on novel strategies for bone and cartilage tissue engineering in the European Orthopaedic Research Society (EORS) conference meeting 2023, which will be held on the 27th-29th September at the Alfandega Porto Congress Centre, Porto-Portugal.

The repair of bone defects remains an important challenge in current orthopaedic clinical practice. Novel approaches, including electrical stimulation-based therapies, have been gaining traction due to their encouraging results in both in vivo and in vitro settings. The development of electroconductive scaffolds to assist this type of therapy holds significant promise, as such constructs could be used to guide electrical stimuli directly to the damaged site, therefore increasing the effectiveness of the regeneration process. In an article recently published in the journal International Journal of Molecular Sciences, iBB researchers Frederico Barbosa, João Silva, Fábio Garrudo and Frederico Ferreira, in collaboration with colleagues from Instituto de Telecomunicações (IT) and CERENA, developed mineralized and electroconductive PEDOT:PSS-based nanofibers with bone-like features. This project was developed under the scope of Frederico Barbosa’s PhD thesis, supervised by Frederico Ferreira and João Silva.

Advances in bioprocessing technologies have allowed the scalable and reproducible fabrication of tissue engineering (TE) constructs with higher structural complexity and functionality, achieving a closer mimicry of native-like microenvironments. The Research Topic co-edited by iBB researchers Dr. João C. Silva and Dr. Carlos Rodrigues in collaboration with Prof. Eirini Velliou (University College London, UK) and Prof. Diana Massai (Politecnico di Torino, Italy) aims to provide an overview of the major advances in bioprocessing technologies and methods for TE and regenerative medicine applications. Relevant strategies involving bioreactors, microfluidic systems, 3D bio-printed tissues and organ-on-chips that provide biomimetic, monitored, and controlled 3D in vitro culture conditions for the biophysical stimulation of cells or TE constructs towards improved functionality will receive special attention. Novel stem cell bioengineering and biomaterial-based approaches applied to regenerative medicine and in vitro disease modelling are also of special interest, together with new technologies for biological tissue characterization or for identifying and testing innovative pharmacological treatments. Moreover, innovative in silico and AI-based approaches paving the way towards optimized and automated TE strategies are also welcomed.

This Research Topic invites contributions (Original Research articles and Literature Review manuscripts) describing and discussing the most recent and innovative developments in bioprocessing TE strategies for regenerative medicine and disease modelling applications, leveraged by advances in bioreactor systems, novel biomaterials, 3D bioprinting methods, imaging and biosensing, computational modelling, AI and machine learning, among others.

As current treatments for periodontitis have failed to promote tissue repair and the coordinated regeneration of the whole periodontium, innovative therapeutic strategies are urgently needed to improve the clinical outcomes. Electrospun nanofibrous scaffolds are particularly promising for applications in periodontal regeneration since they are able to mimic the native tissue extracellular matrix (ECM) features such as the size and alignment of the fibers present in the periodontal ligament (PDL). In this article recently published in the journal Nanomaterials, iBB researchers MSc Mafalda Santos, Dr. Marta Carvalho and Dr. João Silva provided an overview of the current state of the art of the application of electrospun nanofibers in periodontal regeneration, either as guided tissue regeneration (GTR) membranes or as scaffolds for tissue engineering strategies.

Understanding the mechano–biological coupling mechanisms of biomaterials for tissue engineering is of major importance to assure proper scaffold performance in situ. Therefore, it is of paramount importance to establish correlations between biomaterials, their processing conditions, and their mechanical behaviour, as well as their biological performance. In a collaborative work between CDRSP-Politécnico de Leiria and SCERG-iBB  (João C. Silva and Frederico Ferreira), it was possible to infer a correlation between the addition of different concentrations of graphene nanoparticles (GPN) in three-dimensional poly(ε-caprolactone) (PCL)-based scaffolds, their extrusion-based processing parameters, and the lamellar crystal orientation observed in the different scaffolds through small-angle X-ray scattering experiments. Moreover, in vitro cell culture studies performed at SCERG-iBB demonstrated the suitability and potential of these novel 3D PCL/GPN scaffolds for tissue engineering applications. The results of this study were just published in Polymers.

The research project “InSilico4OCReg - In silico models guiding in vitro biophysical stimulation of biomimetic hierarchical scaffolds: a computational modelling approach towards functional osteochondral regeneration” was recommended for funding by FCT (250,000 euros in the 2021 Call for SR&TD Project Grants). The project started in January 2022 and aims to develop an innovative combined in silico modelling-in vitro experimental system which, inspired by the properties of the native osteochondral tissue, will be able to optimize tissue engineering strategies towards the production of implants with improved functionality and mechanical properties. The multidisciplinary team of InSilico4OCReg includes researchers from iBB, CDRSP-Politécnico de Leiria, Rensselaer Polytechnic Institute (Troy, NY-USA), and an orthopedic surgeon (Hospital dos Lusíadas). The project, which falls within the scientific area of Mechanical Engineering-Engineering Systems, is headed by João Carlos Silva (PI, SCERG-iBB) and Prof. Paula Pascoal-Faria (co-PI, CDRSP-Politécnico de Leiria).

Bioreactors that provide different biophysical stimuli have been used in tissue engineering approaches aimed at enhancing the quality of the cartilage tissue generated. However, such systems are often highly complex, costly and not very versatile. In a recent study published in Biotechnology Journal, researchers from SCERG-iBB working with colleagues from the Polytechnic Institute of Leiria and Rensselaer Polytechnic Institute (USA) developed a novel, cost-effective and customizable perfusion bioreactor fabricated by additive manufacturing (AM) to study of the effect of fluid flow on the chondrogenic differentiation of human bone-marrow mesenchymal stem/stromal cells (hBMSCs) in 3D porous poly (ε-caprolactone) (PCL) scaffolds. Results suggest that the chondrogenic differentiation of hBMSCs was enhanced in cell-scaffold constructs cultured under perfusion and highlights the potential of customizable AM platforms for developing more reliable in vitro models and improved personalized cartilage repair strategies.

Cell-derived ECM have emerged as promising materials for regenerative medicine due to their ability to recapitulate the native tissue microenvironment. However, little is known about the glycosaminoglycan (GAG) composition of these cell-derived ECM. In a recent study published in Glycoconjugate Journal, researchers from SCERG-iBB, working in collaboration with colleagues from the Rensselaer Polytechnic Institute, characterized three different cell-derived ECM in terms of their GAG content, composition and sulfation patterns using a highly sensitive LC-MS/MS technique. Distinct GAG compositions and disaccharide sulfation patterns were verified for the different cell-derived ECM. Additionally, the effect of decellularization method on the GAG and disaccharide relative composition was also assessed. The method offers a novel approach to determine the GAG composition of cell-derived ECM, which we believe is critical for a better understanding of ECM role in directing cellular responses and has the potential for generating important knowledge for the development of new ECM-like biomaterials for tissue engineering applications.

The production of piezoelectric constructs in order to address osteoporotic-related fractures holds significant promise. Such scaffolds could be used to mimic the native piezoelectric features of bone as well as assisting electrical stimulation-based therapies, which have been found to accelerate bone repair. In an article recently published in the journal Science and Technology of Advanced Materials, iBB researchers Frederico Barbosa, João Silva, Fábio Garrudo, Marta Carvalho, Paola Alberte, Leonor Resina and Frederico Ferreira, in collaboration with colleagues from the University of Nottingham and the Universitat Politècnica de Catalunya, developed novel hydroxyapatite-filled PVDF-TrFE nanofibers with enhanced piezoelectrical properties and osteogenic potential.

Magnetic hydrogels have recently been drawing a lot of attention in the scientific community due to their remote controllability and high biocompatibility. By combining these materials with a 3D bioprinting technique, it is possible to fabricate intricate structures responsive to an external magnetic stimulus, thus allowing the tuning of the constructs properties to better recapitulate the microarchitecture of native tissues. In this article recently published in the International Journal of Bioprinting, iBB researchers Duarte Almeida, Paola Sanjuan-Alberte, João C. Silva and Frederico Ferreira provided an overview of the current state of the art of magnetic hydrogels, exploring the production of the magnetic components and their introduction in the hydrogels, and emphasizing the current research made on the applications of these materials for tissue engineering strategies.

The irreversible progressive nature of degenerative osteochondral defects, affecting both articular cartilage and the subchondral bone, is a leading cause for joint disease and disability among adults, resulting in severe limitations for people to perform daily activities and represents a heavy economic burden for society. Current treatments do no provide adequate long-term solutions and innovative tissue engineering strategies are regarded as a promising alternative to improve clinical outcomes. A key aspect that needs to be considered is the integration between native tissue and the tissue engineered construct. In this recent article resulting from a collaboration between researchers from iBB and CDRSP-Politécnico de Leiria, published in the Journal Polymers, a new approach to design and manufacture curved scaffolds to mimic osteochondral tissue geometry was presented. The curvature of the sphere was proposed as a template and a procedure was developed for an automated design of scaffolds with explicitly defined curvatures. Fused filament fabrication (3D-Printing) was used for scaffolds’ manufacturing. A Shape fidelity analysis implemented through micro-CT and SEM imaging validated the maximum curvature printability limit predicted from CAD modeling and confirmed the suitability of fused filament fabrication to manufacture curvature-featuring scaffolds. Additionally, a mechanical analysis was conducted with printed scaffolds and through finite element analysis to determine scaffold mechanical properties and identify the regions more susceptible to higher loads.

As current treatment options for cartilage degeneration remain ineffective, tissue engineering has emerged as an exciting approach to create cartilage substitutes. In particular, hydrogels seem to be suitable candidates for this purpose due to their high biocompatibility and customizability, being able to be tailored to fit the biophysical properties of native cartilage. Moreover, these hydrogel matrices can be combined with conductive materials in order to simulate the natural electrochemical properties of articular cartilage. In this recent review published in the journal Gels, iBB researchers Filipe Miguel (MSc student in Biotechnology), Frederico Barbosa (PhD student in Bioengineering), Prof. Frederico Ferreira and Dr. João Silva highlight the most common conductive materials combined with hydrogels and their diverse applications, and discuss the current state of research on the development of electrically conductive hydrogels for cartilage tissue engineering.

João Carlos Silva and Frederico Castelo Ferreira from SCERG-iBB are guest-editing a special issue for the open-access journal “Polymers” entitled “Advanced Polymeric Scaffolds for Stem Cell Engineering and Regenerative Medicine”. Polymer scaffolds play a crucial role in tissue engineering and regenerative medicine applications since they can closely mimic the architecture of a native extracellular matrix (ECM) and improve the biological performance of cells both in vitro and in vivo. This Special Issue welcomes full research papers, communications and reviews on recent exciting developments of polymeric scaffolds for tissue engineering and regenerative medicine applications.