Tissue engineering: from basic sciences to clinical perspectives

[Excerpt] Tissue engineering and regenerative medicine are interre-lated terms and go hand in hand whether we discuss aboutcells (of any kind especially stem and progenitor cells), bio-materials as matrices (2D films, 3D forms of scaffolds,nanofibers, hydrogels, nanoparticles, aerogel, microcapsules,mats, biogel for 3D printing, blends of naturals and/or syn-thetics, and others), and addition of bioactive molecules(delivery of growth hormones and drugs) for improvementand/or regeneration of tissues for biomedical applications (inrelation to cartilage, shin, bone, blood vessels, nerve conduits,cardiac, adipose, tissue expression, and others). Therefore,it includes basic principles of biological sciences, materialchemistry, and relevant engineering subjects. Finally formedical applications after proper clinical verifications of theappropriate films, scaffolds, devices, delivery systems, andother relevant products are needed. [...

Postoperative infectious complications in head and neck cancer surgery

Aim: In our work we have considered the problems related to the post-operative hospitalization in patients admitted to our ENT's department in the last 4 years. Material of study: Our observations refer to a sample of 155 patients suffering from head and neck tumors. Results: Regarding therapy, some drugs have been less effective to prevent post-operative infection: the ceftriaxone at the level of the oral cavity/oropharynx and ceftriaxone/pefloxacin at the level of the hypopharynx/larynx. Discussion: Post-operative infections in cancer surgery can compromise not only the surgical outcome but also be responsible for delays for any adjuvant treatments. Post-operative infections risk in head-neck cancer surgery drops from 30- 80 % to 20 % with perioperative antibiotic prophylaxis. Despite the introduction of pre-operative prophylaxis , according to guidelines, the number of post-surgical infections still remains high (40/61% of cases). It is important to know the intrinsic risk factors (related to the patient) and extrinsic (related to the external environment and the same procedure) to better understand how to prevent infections. Prolonged hospitalization can expose patients to the risk of hospital pathogens. Conclusion: We tried to outline a profile of head-neck cancer patients more likely to contract post-operative infections. We also compared the effects of various antibiotics administered before and after the onset of complications to suggest a therapeutic protocol. Key words: Antibiotics therapy Post-operative infectious, Prophylaxis in head and neck surgery

Regenerated silk fibroin membranes as separators for transparent microbial fuel cells

Abstract In recent years novel applications of bioelectrochemical systems are exemplified by phototrophic biocathodes, biocompatible enzymatic fuel cells and biodegradable microbial fuel cells (MFCs). Herein, transparent silk fibroin membranes (SFM) with various fibroin content (2%, 4% and 8%) were synthesised and employed as separators in MFCs and compared with standard cation exchange membranes (CEM) as a control. The highest real-time power performance of thin-film SFM was reached by 2%-SFM separators: 25.7 ± 7.4 μW, which corresponds to 68% of the performance of the CEM separators (37.7 ± 3.1 μW). Similarly, 2%-SFM revealed the highest coulombic efficiency of 6.65 ± 1.90%, 74% of the CEM efficiency. Current for 2%-SFM reached 0.25 ± 0.03 mA (86% of CEM control). Decrease of power output was observed after 23 days for 8% and 4% and was a consequence of deterioration of SFMs, determined by physical, chemical and biological studies. This is the first time that economical and transparent silk fibroin polymers were successfully employed in MFCs

Fabrication of anisotropically aligned nanofibrous scaffolds based on natural/synthetic polymer blends reinforced with cellulose nanocrystals for tendon tissue engineering

[Excerpt] Introduction: Tendon disorders and injuries are among the most common musculoskeletal problems and their regeneration after injury remains a significant challenge. Given the prevalent fibrous nature of tendons’ ECM, which exhibits an aligned and hierarchical organization in structures from the nano to the macro scale, uniaxial aligned electrospun nanofibers produced from natural/synthetic polymer blends are among the most successful tendon scaffolds in tissue engineering (TE) strategies[1]. These biomaterials can provide the topographical cues to direct cell adhesion and proliferation, as well as positively affecting cell’s differentiation, phenotype maintenance and matrix deposition. However, the limited mechanical properties of electrospun biomaterials restrict their potential application in this field. In the present study, we propose the use of cellulose nanocrystals (CNCs), the “nature carbon nanotubes”, as a strategy for the reinforcement of electrospun poly­ɛ­caprolactone­chitosan (PCL­C) nanofiber scaffolds without compromising their biological performance and thus expand their potential range of application in tendon TE strategies. (...

Biofunctional Silk Kirigami With Engineered Properties.

The fabrication of multifunctional materials that interface with living environments is a problem of great interest. A variety of structural design concepts have been integrated with functional materials to form biodevices and surfaces for health monitoring. In particular, approaches based on kirigami-inspired cuts can engineer flexibility in materials through the creation of patterned defects. Here, the fabrication of a biodegradable and biofunctional "silk kirigami" material is demonstrated. Mechanically flexible, free-standing, optically transparent, large-area biomaterial sheets with precisely defined and computationally designed microscale cuts can be formed using a single-step photolithographic process. Using modeling techniques, it is shown how cuts can generate remarkable "self-shielding" leading to engineered elastic behavior and deformation. As composites with conducting polymers, flexible, intrinsically electroactive sheets can be formed. Importantly, the silk kirigami sheets are biocompatible, can serve as substrates for cell culture, and be proteolytically resorbed. The unique properties of silk kirigami suggest a host of applications as transient, "green", functional biointerfaces, and flexible bioelectronics

Re-Ingeniería de apatita natural para soporte de tejidos óseos

Actualmente los grandes progresos en la medicina ortopédica, traumatológica y odontológica, han originado una gran necesidad por biomateriales, especialmente por aquellos productos que tienen una composición en base de ortofosfato de calcio, el cual es similar a la estructura inorgánica de los huesos. Ante este escenario, se ha generado una intensa búsqueda de nuevos orígenes y recursos, siendo los materiales naturales un foco de importantes estudios, debido a que estos pueden abastecer plenamente la gran demanda por biomateriales. Los estudios de estos materiales naturales han reportado interesantes avances, especialmente en lo que respecta a la regeneración de tejidos biológicos en medicina reparativa. De manera de seguir contribuyendo con este desafío, se analizaron muestras de minerales provenientes de un extenso depósito geológico hidrotermal, para proponer estos materiales como posible fuente de recursos. Los minerales extraídos fueron disgregados, para posteriormente fabricar probetas cilíndricas mediante Sinterización por Arco de Plasma, para luego ser biológicamente testeadas. La caracterización mineralógica del material extraído, reveló altos contenidos de fosfatos en forma de apatita, seguidas de pequeñas cantidades de otras especies mineralógicas asociadas, como el cuarzo y yeso. Dadas estas características, el polvo de mineral presentó una buena disposición a la sinterización, siendo capaz de densificar completamente a temperatura sobre los 1000ºC. Los resultados de la sinterización fueron correlacionados con las fases obtenidas con las diferentes temperaturas de proceso, presentando la apatita muy buena estabilidad termoquímica. Pruebas preliminares in vitro de proliferación y adhesión celular de osteoblastos humanos, MG63, en las muestras preparadas, parecen ser bastantes prometedoras, siendo la probeta sinterizada a 1200ºC la que presentó la mejor activación celular, semejante al comportamiento biológico de las hidroxiapatitas comerciales reportadas

Cholesteatoma vs granulation tissue: a differential diagnosis by DWI-MRI apparent diffusion coefficient

To diagnose cholesteatoma when it is not visible through tympanic perforation, imaging techniques are necessary. Recently, the combination of computed tomography and magnetic resonance imaging has proven effective to diagnose middle ear cholesteatoma. In particular, diffusion weighted images have integrated the conventional imaging for the qualitative assessment of cholesteatoma. Accordingly, the aim of this study was to obtain a quantitative analysis of cholesteatoma calculating the apparent diffusion coefficient value. So, we investigated whether it could differentiate cholesteatoma from other inflammatory tissues both in a preoperative and in a postoperative study

Human amniotic fluid-derived and dental pulp-derived stem cells seeded into collagen scaffold repair critical-size bone defects promoting vascularization

INTRODUCTION: The main aim of this study is to evaluate potential human stem cells, such as dental pulp stem cells and amniotic fluid stem cells, combined with collagen scaffold to reconstruct critical-size cranial bone defects in an animal model. METHODS: We performed two symmetric full-thickness cranial defects on each parietal region of rats and we replenished them with collagen scaffolds with or without stem cells already seeded into and addressed towards osteogenic lineage in vitro. After 4 and 8 weeks, cranial tissue samples were taken for histological and immunofluorescence analysis. RESULTS: We observed a new bone formation in all of the samples but the most relevant differences in defect correction were shown by stem cell–collagen samples 4 weeks after implant, suggesting a faster regeneration ability of the combined constructs. The presence of human cells in the newly formed bone was confirmed by confocal analysis with an antibody directed to a human mitochondrial protein. Furthermore, human cells were found to be an essential part of new vessel formation in the scaffold. CONCLUSION: These data confirmed the strong potential of bioengineered constructs of stem cell–collagen scaffold for correcting large cranial defects in an animal model and highlighting the role of stem cells in neovascularization during skeletal defect reconstruction