Fabrication of a novel hierarchical fibrous scaffold for breast cancer cell culture

Supplementary data to this article can be found online at https://doi.org/10.1016/j.polymertesting.2019.106107.Scaffolds combining nano- and submicro-fibers closely mimicking extracellular matrix (ECM) have been poorly exploited for in vitro cancer cell culture. Herein, a combined electrospinning and modified in situ biosynthesis method has been developed to fabricate a novel scaffold consisting of bacterial cellulose (BC) nanofibers and electrospun cellulose acetate (CA) submicrofibers to mimic the fibrillar structure of natural ECM. The CA/BC nano/submicrofibrous scaffold was characterized by scanning electron microscopy (SEM), mechanical strength tests, porosity measurements, and cell studies using the MCF-7 breast cancer cells. In addition, the sensitivity of the cancer cells seeded in the CA/BC nano/submicrofibrous scaffold to an anticancer drug was assessed. It was found that the CA/BC scaffold exhibited an interconnected porous structure in which BC nanofibers penetrated into the submicrofibrous CA scaffold. Such sophisticated structure was responsible for the improved mechanical properties of CA/BC scaffold over the ones obtained using a single kind of fibers. More importantly, the CA/BC scaffold showed improved cell adhesion, migration, and proliferation over single BC or CA scaffold. Finally, cells grown on CA/BC scaffold exhibited a greater doxorubicin resistance than those on single CA or BC scaffold. The results suggest that the CA/BC nano/submicrofibrous scaffold has potential for application in in vitro tumor model for the study of cancer progression and drug screening.This work was supported by the Key Project of Natural Science Foundation of Jiangxi Province (Grant no. 20161ACB20018), the National Natural Science Foundation of China (Grant nos. 31870963, 31660264, and 51572187), the Youth Science Foundation of Jiangxi Province (Grant no. 20181BAB216010), and the Science and Technology Research Project of Jiangxi Education Department (Grant no. GJJ180348).info:eu-repo/semantics/publishedVersio

ARTIFICIAL SYNTHETIC SCAFFOLDS FOR TISSUE ENGINEERING APPLICATION EMPHASIZING THE ROLE OF BIOPHYSICAL CUES

The mechanotransduction of cells is the intrinsic ability of cells to convert the mechanical signals provided by the surrounding matrix and other cells into biochemical signals that affect several distinct processes such as tumorigenesis, wound healing, and organ formation. The use of biomaterials as an artificial scaffold for cell attachment, differentiation and proliferation provides a tool to modulate and understand the mechanotransduction pathways, develop better in vitro models and clinical remedies. The effect of topographical cues and stiffness was investigated in fibroblasts using polycaprolactone (PCL)- Polyaniline (PANI) based scaffolds that were fabricated using a self-assembly method and electrospinning. Through this method, scaffolds of different topography and stiffness were fabricated with similar surface chemistries. The effect of scaffold morphologies on the cells were investigated. PCL scaffolds of three distinct morphologies- honeycomb, aligned and mesh were used with similar surface chemistry to investigate the changes in cell behavior of breast, renal, lung and bladder cancer to the physical cues. Selective adhesion and localization of cells to specific morphologies were determined. In order to demonstrate the scaffold as a source of biochemical signals, ManCou-H, capable of targeting the fructose-specific glucose transporter GLUT5 was electrospun with the scaffolds of different morphologies. The PCL scaffolds were used as the backbone to release ManCou-H and changes in protein expression and metabolic activity was characterized. The findings made available through this research will help in the design of better cell-specific in vitro model systems to better understand cellular responses to clinical therapies, assess cell response to specific mechanical and chemical cues

Electrospinning and emerging healthcare and medicine possibilities

Electrospinning forms fibers from either an electrically charged polymer solution or polymer melt. Over the past decades, it has become a simple and versatile method for nanofiber production. Hence, it has been explored in many different applications. Commonly used electrospinning assembles fibers from polymer solutions in various solvents, known as solution electrospinning, while melt and near-field electrospinning techniques enhance the versatility of electrospinning. Adaption of additive manufacturing strategy to electrospinning permits precise fiber deposition and predefining pattern construction. This manuscript critically presents the potential of electrospun nanofibers in healthcare applications. Research community drew impetus from the similarity of electrospun nanofibers to the morphology and mechanical properties of fibrous extracellular matrices (ECM) of natural human tissues. Electrospun nanofibrous scaffolds act as ECM analogs for specific tissue cells, stem cells, and tumor cells to realize tissue regeneration, stem cell differentiation, and in vitro tumor model construction. The large surface-to-volume ratio of electrospun nanofibers offers a considerable number of bioactive agents binding sites, which makes it a promising candidate for a number of biomedical applications. The applications of electrospinning in regenerative medicine, tissue engineering, controlled drug delivery, biosensors, and cancer diagnosis are elaborated. Electrospun nanofiber incorporations in medical device coating, in vitro 3D cancer model, and filtration membrane are also discussed

Bone regeneration in patient-specific scaffolds from microfluidics to computational simulation

Los trastornos musculoesqueléticos y sus correspondientes enfermedades óseas son una de las principales causas de dolor y discapacidad, así como una carga social y económica para nuestra sociedad. Cuando la función articular se ve afectada o los defectos óseos son demasiado grandes para los injertos óseos, los implantes protésicos son el método estándar para tratar los trastornos musculoesqueléticos graves, aunque existe la necesidad clínica de que los implantes permanezcan activos durante un período de tiempo más largo y reduzcan las tasas de revisión. Para abordar la mayor durabilidad de los implantes ortopédicos, recientemente han surgido implantes impresos en tres dimensiones (3D) para fabricar superficies porosas específicas del paciente en la superficie del hueso-implante, mejorando así la fijación biológica del implante. La traslación de los principios de la medicina regenerativa a la ortopedia permitiría definir una nueva generación de implantes que completen la transición de materiales inertes a andamios bioactivos que guíen el proceso de regeneración ósea. A corto plazo, es probable que los andamios ortopédicos regenerativos impresos en 3D aumenten la vida útil del implante, mientras que a largo plazo puedan degradarse una vez que el tejido huésped esté completamente reparado. El objetivo global de esta tesis es evaluar el potencial regenerativo asociado a los andamiajes óseos impresos en 3D para aplicaciones ortopédicas específicas del paciente.Para ello, el primer estudio tuvo como objetivo determinar el papel del entorno mecánico del huésped en el proceso de regeneración ósea guiado por andamios óseos impresos en 3D en aplicaciones de carga. Se desarrolló un modelo computacional de regeneración ósea impulsada por un mecanismo en andamios porosos y se basó en la especificidad del sujeto, el sitio de implantación y la sensibilidad al entorno mecánico. A continuación, se simuló el crecimiento óseo en el interior de andamiajes porosos de titanio implantados en el fémur distal y la tibia proximal de tres cabras y se comparó con los resultados experimentales. Los resultados mostraron que el crecimiento óseo en el interior cambió de un patrón de distribución homogéneo, cuando los andamios estaban en contacto con el hueso trabecular, a un crecimiento óseo localizado cuando los andamios se implantaron en una ubicación diafisaria. En general, la dependencia de la respuesta osteogénica de la biomecánica del huésped sugirió que, desde una perspectiva mecánica, el potencial regenerativo dependía tanto del andamio como del entorno del huésped.El segundo estudio de esta tesis tuvo como objetivo evaluar la actividad osteogénica específica del paciente en un entorno controlado in vitro donde las células óseas humanas, aisladas de sujetos individuales, imitan los rasgos esenciales del proceso de formación ósea. Los sistemas in vitro tradicionales ya permitieron demostrar que los osteoblastos humanos primarios embebidos en una matriz fibrada de colágeno se diferencian en osteocitos en condiciones específicas. Por lo tanto, se planteó la hipótesis de que la traslación de este entorno a la escala de órgano en un chip crea una unidad funcional mínima para recapitular la maduración de los osteoblastos hacia los osteocitos y la mineralización de la matriz. Con este propósito, se sembraron osteoblastos humanos primarios en un hidrogel de colágeno de tipo I, para conocer mejor el papel de la densidad de siembra de células en su diferenciación a osteocitos. Los resultados muestran que las células cultivadas a mayor densidad aumentan la longitud de la dendrita con el tiempo, dejan de proliferar, exhiben morfología dendrítica, regulan positivamente la actividad de la fosfatasa alcalina y expresan marcadores de osteocitos. Este estudio reveló que los sistemas de microfluídica son una estrategia funcional que permite crear un modelo de tejido óseo específico del paciente e investigar el potencial osteogénico individual de las células óseas del paciente.En conjunto, los resultados de esta tesis enfatizan la importancia de utilizar un sistema de modelado múltiple al investigar el proceso de regeneración in vivo guiado por armazones óseos específicos adecuados al paciente. Ambos actores de una estrategia regenerativa libre de células in situ, a saber, el andamio y el paciente, tienen un efecto significativo en el resultado regenerativo final y necesitan ser modelados. Las técnicas avanzadas de in vitro e in silico, combinadas con datos de in vivo, evalúan aspectos distintivos del proceso de regeneración ósea para aplicaciones específicas del paciente. Las futuras estrategias personalizadas de ingeniería de tejidos podrían depender de la integración de esos modelos para mitigar en última instancia la variabilidad en el proceso de regeneración ósea guiado por un andamio específico para el paciente.<br /

Rebuilding the hematopoietic stem cell niche: Recent developments and future prospects

Hematopoietic stem cells (HSCs) have proven their clinical relevance in stem cell transplantation to cure patients with hematological disorders. Key to their regenerative potential is their natural microenvironment – their niche – in the bone marrow (BM). Developments in the field of biomaterials enable the recreation of such environments with increasing preciseness in the laboratory. Such artificial niches help to gain a fundamental understanding of the biophysical and biochemical processes underlying the interaction of HSCs with the materials in their environment and the disturbance of this interplay during diseases affecting the BM. Artificial niches also have the potential to multiply HSCs in vitro, to enable the targeted differentiation of HSCs into mature blood cells or to serve as drug-testing platforms. In this review, we will introduce the importance of artificial niches followed by the biology and biophysics of the natural archetype. We will outline how 2D biomaterials can be used to dissect the complexity of the natural niche into individual parameters for fundamental research and how 3D systems evolved from them. We will present commonly used biomaterials for HSC research and their applications. Finally, we will highlight two areas in the field of HSC research, which just started to unlock the possibilities provided by novel biomaterials, in vitro blood production and studying the pathophysiology of the niche in vitro. With these contents, the review aims to give a broad overview of the different biomaterials applied for HSC research and to discuss their potentials, challenges and future directions in the field. Statement of significance Hematopoietic stem cells (HSCs) are multipotent cells responsible for maintaining the turnover of all blood cells. They are routinely applied to treat patients with hematological diseases. This high clinical relevance explains the necessity of multiplication or differentiation of HSCs in the laboratory, which is hampered by the missing natural microenvironment – the so called niche. Biomaterials offer the possibility to mimic the niche and thus overcome this hurdle. The review introduces the HSC niche in the bone marrow and discusses the utility of biomaterials in creating artificial niches. It outlines how 2D systems evolved into sophisticated 3D platforms, which opened the gateway to applications such as, expansion of clinically relevant HSCs, in vitro blood production, studying niche pathologies and drug testing

Composite nanoclay-hydroxyapatite-polymer fiber scaffolds for bone tissue engineering manufactured using pressurized gyration

A novel fabrication of polymer composite fibers using polycaprolactone (PCL), montmorillonite nanoclay (MMT-Clay), and nano-hydroxyapatite-clay (HAP MMT-Clay) is reported for bone tissue engineering applications. Using a pressurized gyration (PG) setup, polycaprolactone (PCL) fibers incorporated with in situ mineralized HAP MMT-Clay and MMT-Clay were investigated. Using the novel fabrication method, we were able to successfully manufacture HAP-nanoclay-PCL fibers. Further, 3D scaffolds made using the prepared fibers were able to enhance bone growth, cell viability, and proliferation. The results demonstrated that the polymer fiber scaffolds are biocompatible, and the cells were able to thrive and differentiate on the fiber scaffolds. A significant increase in cell viability, osteogenic differentiation, ECM formation, and collagen formation was observed with PCL HAP MMT-Clay fibers scaffolds compared to the behaviors in PCL fibers. Further, the intracellular ALP levels increased with PCL HAP MMT-Clay fiber scaffold, indicating enhanced osteogenic differentiation of MSCs. This work shows a promising outlook for the future of manufacturable composite nanoclay polymer fibers incorporated as scaffolds for bone tissue engineering applications

3d printing and bioprinting to model bone cancer: The role of materials and nanoscale cues in directing cell behavior

open5noThis work was supported by theEranet-lac (PER-2012-ELAC2015/T07-0713 to N.B.), the Italian Association for Cancer Research (AIRC IG n. 21403 to N.B.), the Ministry of Health (project Starting Grant SG-2018-12367059, BANDO RICERCA FINALIZZATA 2018 to G.G.). Financial support for Scientific Research 5xMille to N.BBone cancer, both primary and metastatic, is characterized by a low survival rate. Cur-rently, available models lack in mimicking the complexity of bone, of cancer, and of their microen-vironment, leading to poor predictivity. Three-dimensional technologies can help address this need, by developing predictive models that can recapitulate the conditions for cancer development and progression. Among the existing tools to obtain suitable 3D models of bone cancer, 3D printing and bioprinting appear very promising, as they enable combining cells, biomolecules, and biomaterials into organized and complex structures that can reproduce the main characteristic of bone. The chal-lenge is to recapitulate a bone-like microenvironment for analysis of stromal–cancer cell interactions and biological mechanics leading to tumor progression. In this review, existing approaches to obtain in vitro 3D-printed and-bioprinted bone models are discussed, with a focus on the role of biomateri-als selection in determining the behavior of the models and its degree of customization. To obtain a reliable 3D bone model, the evaluation of different polymeric matrices and the inclusion of ceramic fillers is of paramount importance, as they help reproduce the behavior of both normal and cancer cells in the bone microenvironment. Open challenges and future perspectives are discussed to solve existing shortcomings and to pave the way for potential development strategies.openFischetti T.; Di Pompo G.; Baldini N.; Avnet S.; Graziani G.Fischetti T.; Di Pompo G.; Baldini N.; Avnet S.; Graziani G