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1.
Revisiting the insights and applications of protein engineered hydrogels.
J, B, Chanda, K, M M, B
Materials science & engineering. C, Materials for biological applications. 2019;:312-327
Abstract
Utilization of protein-protein interactions or protein-peptide interactions has led to new crosslinking chemistries, resulting into protein hydrogels. Enzyme catalyzed crosslinking of specific amino acids has also been used to generate crosslinked protein hydrogels. Weak, temporary, reversible or non-covalently crosslinked protein gels as well as strong, permanent, irreversible or covalently crosslinked protein gels with mechanical strengths of varying degrees are generated by means of various crosslinking strategies. These protein hydrogels are tailored by means of protein engineering and recombinant DNA technology, depending on its end use as scaffolds for specific tissue engineering, drug delivery, wound dressings etc. This review aims to cover the advancements in the use of protein engineering along with different crosslinking techniques to create novel protein hydrogels that finds various applications in biomedical industries.
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2.
Dynamic in vitro models for tumor tissue engineering.
Karami, D, Richbourg, N, Sikavitsas, V
Cancer letters. 2019;:178-185
Abstract
Cancer research uses in vitro studies for controllable analysis of tumor behavior and preclinical testing of therapeutics. Shortcomings of basic cell culture systems in recreating in vivo interactions have driven the development of more efficient and biomimetic in vitro environments for cancer research. Assimilation of certain developments in tissue engineering will accelerate and improve the design of these environments. With the continual improvement of the tumor engineering field, the next step is towards macroscopic systems such as scaffold-supported, flow-perfused macroscale tumor bioreactors. Surface modifications of synthetic scaffolds allow for targeted cell adhesion and improved ECM development. Flow perfusion has emerged as means to expose cancerous tissues to critical biomechanical forces for tumor progression while simultaneously improving nutrient and waste transport. Macroscale perfusable systems allow for non-destructive real-time monitoring using biosensors capable of improving understanding of in vitro tumor development at reduced cost and waste. The combination of macroscale perfusable systems, surface-modified synthetic scaffolds, and non-destructive real-time monitoring will provide advanced platforms for in vitro modeling of tumor development, with broad applications in basic tumor research and preclinical drug development.
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3.
Enamel biomimetics-fiction or future of dentistry.
Pandya, M, Diekwisch, TGH
International journal of oral science. 2019;(1):8
Abstract
Tooth enamel is a complex mineralized tissue consisting of long and parallel apatite crystals configured into decussating enamel rods. In recent years, multiple approaches have been introduced to generate or regenerate this highly attractive biomaterial characterized by great mechanical strength paired with relative resilience and tissue compatibility. In the present review, we discuss five pathways toward enamel tissue engineering, (i) enamel synthesis using physico-chemical means, (ii) protein matrix-guided enamel crystal growth, (iii) enamel surface remineralization, (iv) cell-based enamel engineering, and (v) biological enamel regeneration based on de novo induction of tooth morphogenesis. So far, physical synthesis approaches using extreme environmental conditions such as pH, heat and pressure have resulted in the formation of enamel-like crystal assemblies. Biochemical methods relying on enamel proteins as templating matrices have aided the growth of elongated calcium phosphate crystals. To illustrate the validity of this biochemical approach we have successfully grown enamel-like apatite crystals organized into decussating enamel rods using an organic enamel protein matrix. Other studies reviewed here have employed amelogenin-derived peptides or self-assembling dendrimers to re-mineralize mineral-depleted white lesions on tooth surfaces. So far, cell-based enamel tissue engineering has been hampered by the limitations of presently existing ameloblast cell lines. Going forward, these limitations may be overcome by new cell culture technologies. Finally, whole-tooth regeneration through reactivation of the signaling pathways triggered during natural enamel development represents a biological avenue toward faithful enamel regeneration. In the present review we have summarized the state of the art in enamel tissue engineering and provided novel insights into future opportunities to regenerate this arguably most fascinating of all dental tissues.
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4.
Bioprinting Approaches to Engineering Vascularized 3D Cardiac Tissues.
Puluca, N, Lee, S, Doppler, S, Münsterer, A, Dreßen, M, Krane, M, Wu, SM
Current cardiology reports. 2019;(9):90
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Abstract
PURPOSE OF REVIEW 3D bioprinting technologies hold significant promise for the generation of engineered cardiac tissue and translational applications in medicine. To generate a clinically relevant sized tissue, the provisioning of a perfusable vascular network that provides nutrients to cells in the tissue is a major challenge. This review summarizes the recent vascularization strategies for engineering 3D cardiac tissues. RECENT FINDINGS Considerable steps towards the generation of macroscopic sizes for engineered cardiac tissue with efficient vascular networks have been made within the past few years. Achieving a compact tissue with enough cardiomyocytes to provide functionality remains a challenging task. Achieving perfusion in engineered constructs with media that contain oxygen and nutrients at a clinically relevant tissue sizes remains the next frontier in tissue engineering. The provisioning of a functional vasculature is necessary for maintaining a high cell viability and functionality in engineered cardiac tissues. Several recent studies have shown the ability to generate tissues up to a centimeter scale with a perfusable vascular network. Future challenges include improving cell density and tissue size. This requires the close collaboration of a multidisciplinary teams of investigators to overcome complex challenges in order to achieve success.
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5.
Generating an Artificial Intestine for the Treatment of Short Bowel Syndrome.
Kovler, ML, Hackam, DJ
Gastroenterology clinics of North America. 2019;(4):585-605
Abstract
Intestinal failure is defined as the inability to maintain fluid, nutrition, energy, and micronutrient balance that leads to the inability to gain or maintain weight, resulting in malnutrition and dehydration. Causes of intestinal failure include short bowel syndrome (ie, the physical loss of intestinal surface area and severe intestinal dysmotility). For patients with intestinal failure who fail to achieve enteral autonomy through intestinal rehabilitation programs, the current treatment options are expensive and associated with severe complications. Therefore, the need persists for next-generation therapies, including cell-based therapy, to increase intestinal regeneration, and development of the tissue-engineered small intestine.
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6.
The applications of regenerative medicine in sinus lift procedures: A systematic review.
Correia, F, Pozza, DH, Gouveia, S, Felino, A, Faria E Almeida, R
Clinical implant dentistry and related research. 2018;(2):229-242
Abstract
BACKGROUND Findings in regenerative medicine applied to the sinus lift procedures. PURPOSE Evaluate the effectiveness of regenerative medicine in sinus lift. MATERIALS AND METHODS An extensive search for manuscripts were performed by using different combinations of keywords and MeSH terms (Pub-med; Embase; Scopus; Web of Science Core Collection; Medline; Current Contents Connect; Derwent Innovations Index; Scielo Citation Index; Cochrane library). The full text selected articles are written in English, Portuguese, Spanish, Italian, German, or French, and published until 28 of November 2016. Inclusion criteria were: implant osteointegration, radiographic, histologic, and/or histomorphometric analysis, clinical studies in humans using of regenerative medicine. This systematic review was performed by selecting only randomized controlled clinical trials and controlled clinical trials. RESULTS Eighteen published studies (11 CT and 7 RCT) were considered eligible for inclusion in the present systematic review. These studies demonstrated considerable variation of biomaterial and cell technics used, study design, sinus lift technic, outcomes, follow-up, and results. CONCLUSION Only few studies have demonstrated potential of regenerative medicine in sinus lift; further randomized clinical trials are needed to achieve more accurate results.
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Alternatives to Autologous Bone Graft in Alveolar Cleft Reconstruction: The State of Alveolar Tissue Engineering.
Liang, F, Leland, H, Jedrzejewski, B, Auslander, A, Maniskas, S, Swanson, J, Urata, M, Hammoudeh, J, Magee, W
The Journal of craniofacial surgery. 2018;(3):584-593
Abstract
Alveolar cleft reconstruction has historically relied on autologous iliac crest bone grafting (ICBG), but donor site morbidity, pain, and prolonged hospitalization have prompted the search for bone graft substitutes. The authors evaluated bone graft substitutes with the highest levels of evidence, and highlight the products that show promise in alveolar cleft repair and in maxillary augmentation. This comprehensive review guides the craniofacial surgeon toward safe and informed utilization of biomaterials in the alveolar cleft.A literature search was performed to identify in vitro human studies that fulfilled the following criteria: Level I or Level II of evidence, ≥30 subjects, and a direct comparison between a autologous bone graft and a bone graft substitute. A second literature search was performed that captured all studies, regardless of level of evidence, which evaluated bone graft substitutes for alveolar cleft repair or alveolar augmentation for dental implants. Adverse events for each of these products were tabulated as well.Sixteen studies featuring 6 bone graft substitutes: hydroxyapatite, demineralized bone matrix (DBM), β-tricalcium phosphate (TCP), calcium phosphate, recombinant human bone morphogenic protein-2 (rhBMP-2), and rhBMP7 fit the inclusion criteria for the first search. Through our second search, the authors found that DBM, TCP, rhBMP-2, and rhBMP7 have been studied most extensively in the alveolar cleft literature, though frequently in studies using less rigorous methodology (Level III evidence or below). rhBMP-2 was the best studied and showed comparable efficacy to ICBG in terms of volume of bone regeneration, bone density, and capacity to accommodate tooth eruption within the graft site. Pricing for products ranged from $290 to $3110 per 5 mL.The balance between innovation and safety is a complex process requiring constant vigilance and evaluation. Here, the authors profile several bone graft substitutes that demonstrate the most promise in alveolar cleft reconstruction.
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8.
From skeletal development to the creation of pluripotent stem cell-derived bone-forming progenitors.
Tam, WL, Luyten, FP, Roberts, SJ
Philosophical transactions of the Royal Society of London. Series B, Biological sciences. 2018;(1750)
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Abstract
Bone has many functions. It is responsible for protecting the underlying soft organs, it allows locomotion, houses the bone marrow and stores minerals such as calcium and phosphate. Upon damage, bone tissue can efficiently repair itself. However, healing is hampered if the defect exceeds a critical size and/or is in compromised conditions. The isolation or generation of bone-forming progenitors has applicability to skeletal repair and may be used in tissue engineering approaches. Traditionally, bone engineering uses osteochondrogenic stem cells, which are combined with scaffold materials and growth factors. Despite promising preclinical data, limited translation towards the clinic has been observed to date. There may be several reasons for this including the lack of robust cell populations with favourable proliferative and differentiation capacities. However, perhaps the most pertinent reason is the failure to produce an implant that can replicate the developmental programme that is observed during skeletal repair. Pluripotent stem cells (PSCs) can potentially offer a solution for bone tissue engineering by providing unlimited cell sources at various stages of differentiation. In this review, we summarize key embryonic signalling pathways in bone formation coupled with PSC differentiation strategies for the derivation of bone-forming progenitors.This article is part of the theme issue 'Designer human tissue: coming to a lab near you'.
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A review on versatile applications of blends and composites of pullulan with natural and synthetic polymers.
Tabasum, S, Noreen, A, Maqsood, MF, Umar, H, Akram, N, Nazli, ZI, Chatha, SAS, Zia, KM
International journal of biological macromolecules. 2018;(Pt A):603-632
Abstract
Pullulan is a non-ionic, linear, water-soluble and a neutral polysaccharide. It is composed of α-(1,6) repeated maltotriose units via α-(1,4) glycosidic bond having chemical formula (C6H10O5)n. It shows non-immunogenic, non-toxic, non-carcinogenic and non-mutagenic properties. It is used in food edible coatings, films, as flocculant, foaming agent and adhesive. It may also be used as a carrier for bioactive compounds and a protective packaging for food and pharmaceutical products. Therefore, it is blended with different polymers such as carrageenan, mucilages, chitosan, cellulose, sodium alginate, starch, polyethyleneimine, whey-protein, polyisopropylacrylamide, histone, jeffamine, polyamidoamine, pemulen, hyaluronic acid, polyvinyl alcohol and caboxymethyl cellulose. In this article, a comprehensive overview of combination of pullulan with natural and synthetic polymers and their applications in biomedical field involving drug delivery system, tissue engineering, wound healing and gene therapy, is presented. It also describes the utilization of pullulan based materials in food industry, water treatment and pharmaceutical industry. All the technical scientific issues have been addressed; highlighting the recent advancements.
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10.
Functional calcium phosphate composites in nanomedicine.
Ridi, F, Meazzini, I, Castroflorio, B, Bonini, M, Berti, D, Baglioni, P
Advances in colloid and interface science. 2017;:281-295
Abstract
Calcium phosphate (CaP) materials have many peculiar and intriguing properties. In nature, CaP is found in nanostructured form embedded in a soft proteic matrix as the main mineral component of bones and teeth. The extraordinary stoichiometric flexibility, the different stabilities exhibited by its different forms as a function of pH and the highly dynamic nature of its surface ions, render CaP one of the most versatile materials for nanomedicine. This review summarizes some of the guidelines so far emerged for the synthesis of CaP composites in aqueous media that endow the material with tailored crystallinity, morphology, size, and functional properties. First, we introduce very briefly the areas of application of CaP within the nanomedicine field. Then through some selected examples, we review some synthetic routes where the presence of functional units (small templating molecules like surfactants, or oligomers and polymers) assists the synthesis and at the same time impart the functionality or the responsiveness desired for the end-application of the material. Finally, we illustrate two examples from our laboratory, where CaP is decorated by biologically active polymers or prepared within a thermo- and magneto-responsive hydrogel, respectively.