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\"Provides an encyclopedic coverage of biomaterials science which, at the same time, has enough to interest the biomedical scientists and engineers\"-- Provided by publisher.

Maintaining long-term euglycemia after intraportal islet transplantation is hampered by the considerable islet loss in the peri-transplant period attributed to inflammation, ischemia and poor angiogenesis. Here, we show that viable and functional islet organoids can be successfully generated from dissociated islet cells (ICs) and human amniotic epithelial cells (hAECs). Incorporation of hAECs into islet organoids markedly enhances engraftment, viability and graft function in a mouse type 1 diabetes model. Our results demonstrate that the integration of hAECs into islet cell organoids has great potential in the development of cell-based therapies for type 1 diabetes. Engineering of functional mini-organs using this strategy will allow the exploration of more favorable implantation sites, and can be expanded to unlimited (stem-cell-derived or xenogeneic) sources of insulin-producing cells. Islet transplantation is a feasible approach to treat type I diabetes, however inflammation and poor vascularisation impair long-term engraftment. Here the authors show that incorporating human amniotic epithelial cells into islet organoids improves engraftment and function of organoids, through enhanced revascularisation.

Given the importance of the extracellular medium during tissue formation, it was wise to develop an artificial structure that mimics the extracellular matrix while having improved physico-chemical properties. That is why the choice was focused on gelatin methacryloyl (GelMA), an inexpensive biocompatible hydrogel. Physicochemical and mechanical properties were improved by the incorporation of nanoparticles developed from two innovative fabrication processes: High shear fluid and low frequencies/high frequencies ultrasounds. Both rapeseed nanoliposomes and nanodroplets were successfully incorporated in the GelMA networks during the photo polymerization process. The impact on polymer microstructure was investigated by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and enzymatic degradation investigations. Mechanical stability and viscoelastic tests were conducted to demonstrate the beneficial effect of the functionalization on GelMA hydrogels. Adding nanoparticles to GelMA improved the surface properties (porosity), tuned swelling, and degradability properties. In addition, we observed that nanoemulsion didn’t change significantly the mechanical properties to shear and compression solicitations, whereas nanoliposome addition decreased Young’s modulus under compression solicitations. Thus, these ways of functionalization allow controlling the design of the material by choosing the type of nanoparticle (nanoliposome or nanoemulsion) in function of the application.

Based on the concept of tissue engineering (Cells—Scaffold—Bioactive molecules), regenerative endodontics appeared as a new notion for dental endodontic treatment. Its approaches aim to preserve dental pulp vitality (pulp capping) or to regenerate a vascularized pulp-like tissue inside necrotic root canals by cell homing. To improve the methods of tissue engineering for pulp regeneration, numerous studies using in vitro, ex vivo, and in vivo models have been performed. This review explores the evolution of laboratory models used in such studies and classifies them according to different criteria. It starts from the initial two–dimensional in vitro models that allowed characterization of stem cell behavior, through 3D culture matrices combined with dental tissue and finally arrives at the more challenging ex vivo and in vivo models. The travel which follows the elaboration of such models reveals the difficulty in establishing reproducible laboratory models for dental pulp regeneration. The development of well-established protocols and new laboratory ex vivo and in vivo models in the field of pulp regeneration would lead to consistent results, reduction of animal experimentation, and facilitation of the translation to clinical practice.

Hydrogels with protein–polysaccharide combinations are widely used in the field of tissue engineering, as they can mimic the in vivo environments of native tissues, specifically the extracellular matrix (ECM). However, achieving stability and mechanical properties comparable to those of tissues by employing natural polymers remains a challenge due to their weak structural characteristics. In this work, we optimized the fabrication strategy of a hydrogel composite, comprising gelatin and sodium alginate (Gel-SA), by varying reaction parameters. Magnetite (Fe3O4) nanoparticles were incorporated to enhance the mechanical stability and structural integrity of the scaffold. The changes in hydrogel stiffness and viscoelastic properties due to variations in polymer mixing ratio, crosslinking time, and heating cycle, both before and after nanoparticle incorporation, were compared. FTIR spectra of crosslinked hydrogels confirmed physical interactions of Gel-SA, metal coordination bonds of alginate with Ca2+, and magnetite nanoparticles. Tensile and rheology tests confirmed that even at low magnetite concentration, the Gel-SA-Fe3O4 hydrogel exhibits mechanical properties comparable to soft tissues. This work has demonstrated enhanced resilience of magnetite-incorporated Gel-SA hydrogels during the heating cycle, compared to Gel-SA gel, as thermal stability is a significant concern for hydrogels containing gelatin. The interactions of thermoreversible gelatin, anionic alginate, and nanoparticles result in dynamic hydrogels, facilitating their use as viscoelastic acellular matrices.

Background Bilateral ocular surface disease resulting from Stevens Johnson Syndrome (SJS) and chemical injuries are visually debilitating and difficult to treat. Ocular surface reconstruction by various means has been reported with variable results. This study addresses an unmet need for a prospective clinical trial comparing the outcomes of transplanting autologous oral and conjunctival epithelial cell constructs on human amniotic membrane by ex vivo tissue engineering. Methods A prospective, randomized controlled clinical trial was prospectively applied for registration, with the clinical trial registry of India (CTRI), with the approval of the Institute Ethics Committee number IEC/NP-99/11.04.2014 and CTRI No. REF/2018/10/021791, the study also registered with the WHO-recognized trial registry, International Standard Randomised Controlled Trial Number (ISRCTN) registration reference number 45780. The study was conducted to compare clinical outcomes of two different tissue-engineered cell grafts, Cultivated Oral Mucosal Epithelial Transplantation (COMET) and Conjunctival Cultivated Epithelial Transplantation (CCET) for ocular surface reconstruction in patients with bilateral ocular surface disease due to Stevens-Johnson Syndrome or chemical injuries. Fifty patients were enrolled and randomized to either the COMET or CCET group. A uniform pre-op and post-op protocol using standard medications was followed for all patients Parameters assessed at baseline, day 1, 1 week, 2 weeks, 1 month, 2 months, 3 months and 6 months postoperatively included patient comfort, best corrected visual acuity (BCVA), ocular surface status and corneal clarity. The efficacy was measured in terms of improvement of vision, reduction in vascularization, symblepharon and corneal clarity. Results In the study, 50 patients (50 eyes; mean ages of 29 ± 15.86 years and 26.36 ± 10.85 years, respectively; range, 12–65 years) were enrolled, with 25 patients each in the COMET and CCET groups. Out of them, 36% were female and 64% were male; the causes were Steven Johnson syndrome (48), and chemical injury (2). Mean pre-operative BCVA was log MAR 1.73 ± 0.57 for COMET and 1.99 ± 0.33 for the CCET group. Pre-operatively all 50 enrolled patients had opaque corneas pre-operatively, symblepharon that extended to the cornea categorised as grade 3 and corneal vascularization that went beyond the pupil’s boundary into the central zone encluaching on the visual axis. The minimal follow-up time was six months. Following surgery postoperatively, the BCVA considerably improved in the COMET group by 1.51 ± 0.58 compared to the CCET group by 1.91 ± 0.33 at 3 months. BCVA at 6 months was 1.73 ± 0.56 in the COMET group and 1.99 ± 0.31 in the CCET group, which is not statistically significant and comparable to the BCVA before surgery. The corneal clarity was significantly improved in COMET group 25 eye (100%) at 2 month, 3month and 19 eye (76%), 6eye (24%) at 6 months when compared to CCET group 15 eye improved (60%), 9 eyes (36%) not improved and one eye with opaque cornea (4%) at 2 months. 22 eye (88%) had not improved, 2 eye (8%) opaque cornea and 1 eye (4%) improved at 3 months. At 6 months 21 eye (84%) were not improved, 4 eye (16%) eye became opaqued at 6 months. Compared to preoperative conditions, both groups had improved corneal clarity significantly ( p  > 0.005). Of the 50 patients with grade 3 symblepharon extended to the cornea, were completely resolved 19 (76%) in COMET group when compared to CCET group 22 eye (88%) not improved. Similarly, 19 eye (76%) had a improvement in corneal vascularization when compared to the CCET group not improved 25 eye (100%) at 6months. No adverse event was observed in any of either group during the follow up periods. Conclusion Both cell types are effective to restore the ocular surface integrity in bilateral ocular surface disease. Whereas COMET is safe and efficacious in terms of improvement of clinical parameters including, BCVA, corneal clarity, reduction in vascularization and preventing the recurrence of symblepharon postoperatively 3months and 6 months. In addition, the CCET group maintained the stability of the ocular surface and had improvement in corneal clarity and a decrease in vascularization at 3 months compared to their pre-operative characteristics.

IntroductionKnee osteoarthritis often starts in the patellofemoral compartment of the knee and is diagnosed in about 39% of people with knee pain aged above 30 years. Patellofemoral osteoarthritis plays a crucial role in the reduction of quality of life and in the rise of healthcare costs. There is still no consensus for treatment recommendation for isolated patella-femoral osteoarthritis in clinical guidelines. Current therapeutic approaches are limited to pain management, alleviation of symptoms or total knee replacement. Nasal chondrocyte tissue-engineered cartilage (N-TEC) has already been successfully introduced in clinical studies phase I and II for the treatment of focal cartilage lesions and in pilot studies in osteoarthritis patients.Methods and analysisA randomised controlled trial involving 75 patients with patellofemoral osteoarthritis from nine different clinical centres in Switzerland, Germany and Croatia is being conducted to evaluate the effectiveness of N-TEC implantation compared with standard treatment with platelet-rich plasma (PRP). In the intervention group, an autologous nasal cartilage cell-derived graft is implanted into the cartilage defects of the patella and/or trochlea during an open surgical procedure. The control group receives three PRP injections at weekly intervals. The primary outcome is the mean Knee Injury and Osteoarthritis Outcome Score Pain Change from baseline to 24 months between groups. Secondary outcomes, including patients’ self-assessed questionnaires, X-ray and MRI scans, physiotherapeutic assessments and safety, will be assessed and compared between the intervention and control group. In addition, the study is complemented with a health-economic evaluation to establish the intervention’s value for money and impact on productivity in working-age individuals. The planned duration of the study is 4 years including baseline and follow-up measurements at 6, 12 and 24 months.Ethics and disseminationAll centres involved in the implementation of the intervention have obtained approval from their respective competent ethics committees. This includes approval from the following ethics committees: Ethics Committees of North-Western and Central Switzerland (EKNZ): 2024–00075 (associated ethical committees: Cantonal Ethics Committee Bern, Cantonal Research Ethics Commission Geneva (CCER), Cantonal Ethics Committee Ticino, Cantonal Ethics Committee Zurich). The EKNZ covers several cantons in Switzerland, including Basel. The site in Lugano falls under the Cantonal Ethics Committee Ticino. Ethics Germany according to CTIS: 2023-508640-21-00 (Medicinal Ethical Commission of the Julius-Maximilians-University Wuerzburg, Ethical Commission of the Albert-Ludwigs-University Freiburg) and Central Ethical Committee Croatia, Republic of Croatia Ministry of Health: 2023-508640-21-00. The Swissmedic reference number is 701788.Prior to participation, all participants must have signed informed consent. Study information will be disseminated via hospital websites, newsletters and an open-access publication of the protocol. Results will be published in peer-reviewed journals, presented at national and international conferences and shared with the public.Trial registration numberClinicalTrials.gov Registration No.: NCT06163573; Registration number CTIS: 2023-508640-21-00.

IntroductionThe current gold standard treatment for patients with orofacial clefts is surgical repair of the palatal defect (uranostaphylorrhaphy), which is associated with growth defects and hypoplasia of the maxillofacial structures. This trial aims to evaluate the potential of a bioengineered artificial palate mucosa, created through tissue engineering with autologous stromal and epithelial cells and nanostructured fibrin–agarose biomaterials, to enhance treatment outcomes for patients with unilateral cleft lip and palate.Methods and analysisThis phase I-IIa clinical trial aims to evaluate the feasibility and biosafety of a procedure involving grafting bioartificial palate mucosa onto the areas of denudated bone in patients undergoing uranostaphylorrhaphy. The control patients will undergo standard surgical treatment. Five patients will be included in the first biosafety phase. In the second phase, 10 patients will be randomly assigned to the intervention or control group (1:1). The intervention group will undergo standard surgical treatment followed by the application of autologous bioartificial palate mucosa. Feasibility will be analysed at the time of surgery. Nine postimplant visits will be scheduled over a 2-year follow-up period, in which local and systemic biosafety will be investigated by determining graft evolution, including signs of necrosis, rejection, inflammation and patient factors. Preliminary signs of efficiency will be explored by sequentially evaluating craniomaxillofacial development, hearing impairment, speech capability and quality of life of the family. The research will be published in journals and posted in the relevant repositories when available.Ethics and disseminationThis study has been approved by the Committee of Ethics in Research with Medicinal Products (CEIm) and authorised by the Spanish Medicines Agency (AEMPS). The results of this study will be published in peer-reviewed journals.Trial registration number NCT06408337; ClinicalTrials.gov: EuclinicalTrials. eu: 2023-506913-23-00.

Brain organoids are invaluable tools for pathophysiological studies or drug screening, but there are still challenges to overcome in making them more reproducible and relevant. Recent advances in three-dimensional (3D) bioprinting of human neural organoids is an emerging approach that may overcome the limitations of self-organized organoids. It requires the development of optimal hydrogels, and a wealth of research has improved our knowledge about biomaterials both in terms of their intrinsic properties and their relevance on 3D culture of brain cells and tissue. Although biomaterials are rarely biologically neutral, few articles have reviewed their roles on neural cells. We here review the current knowledge on unmodified biomaterials amenable to support 3D bioprinting of neural organoids with a particular interest in their impact on cell homeostasis. Alginate is a particularly suitable bioink base for cell encapsulation. Gelatine is a valuable helper agent for 3D bioprinting due to its viscosity. Collagen, fibrin, hyaluronic acid and laminin provide biological support to adhesion, motility, differentiation or synaptogenesis and optimize the 3D culture of neural cells. Optimization of specialized hydrogels to direct differentiation of stem cells together with an increased resolution in phenotype analysis will further extend the spectrum of possible bioprinted brain disease models.