Acta Biomaterialia最新文献

{"title":"Innervation in corneal bioengineering","authors":"Clare Maher ,&nbsp;Zhi Chen ,&nbsp;Ying Zhou ,&nbsp;Jingjing You ,&nbsp;Gerard Sutton ,&nbsp;Gordon Wallace","doi":"10.1016/j.actbio.2024.10.009","DOIUrl":"10.1016/j.actbio.2024.10.009","url":null,"abstract":"<div><div>Given the crucial role nerves play in maintaining corneal function and integrity, the ability of bioengineered cornea to demonstrate functional nerve regeneration directly influences their longevity and stability. Despite advances in biofabrication techniques and an increasing appreciation of the importance of neural innervation, to this day none have completely replicated the complexity and functionality of the cornea with successful innervation. This review evaluates the materials and fabrication techniques used to produce and enhance innervation in bioengineered cornea. Approaches to facilitating innervation are discussed and methods of assessing innervation compared. Finally, current challenges and future directions for innervated bioengineered cornea are presented, providing guidance for future work.</div></div><div><h3>Statement of significance</h3><div>The functional nerve regeneration in bioengineered corneas directly influences their longevity and stability. Despite advancements in biofabrication techniques and growing recognition of the importance of neural innervation for bioengineered cornea, there remains a lack of comprehensive reviews on this topic. This review addresses the critical gap by evaluating the materials and fabrication techniques employed to promote innervation in bioengineered corneas. Additionally, we discuss various approaches to enhancing innervation, compare assessment methods, and examine both <em>in vitro</em> and <em>in vivo</em> responses. By providing a comprehensive overview of the current state of research and highlighting challenges and future directions, this review aims to provide guidance for inducing innervation of bioengineered cornea.</div></div>","PeriodicalId":237,"journal":{"name":"Acta Biomaterialia","volume":"189 ","pages":"Pages 73-87"},"PeriodicalIF":9.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142407320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Navigating Neurotoxicity and Safety Assessment of Nanocarriers for Brain Delivery: Strategies and Insights","authors":"Maria Inês Teixeira ,&nbsp;Carla M. Lopes ,&nbsp;Maria Helena Amaral ,&nbsp;Paulo C. Costa","doi":"10.1016/j.actbio.2024.09.027","DOIUrl":"10.1016/j.actbio.2024.09.027","url":null,"abstract":"<div><div>Nanomedicine, an area that uses nanomaterials for theragnostic purposes, is advancing rapidly, particularly in the detection and treatment of neurodegenerative diseases. The design of nanocarriers can be optimized to enhance drug bioavailability and targeting to specific organs, improving therapeutic outcomes. However, clinical translation hinges on biocompatibility and safety. Nanocarriers can cross the blood-brain barrier (BBB), potentially causing neurotoxic effects through mechanisms such as oxidative stress, DNA damage, and neuroinflammation. Concerns about their accumulation and persistence in the brain make it imperative to carry out a nanotoxicological risk assessment. Generally, this involves identifying exposure sources and routes, characterizing physicochemical properties, and conducting cytotoxicity assays both <em>in vitro</em> and <em>in vivo</em>. The lack of a specialized regulatory framework creates substantial gaps, making it challenging to translate findings across development stages. Additionally, there is a pressing need for innovative testing methods due to constraints on animal use and the demand for high-throughput screening. This review examines the mechanisms of nanocarrier-induced neurotoxicity and the challenges in risk assessment, highlighting the impact of physicochemical properties and the advantages and limitations of current neurotoxicity evaluation models. Future perspectives are also discussed. Additional guidance is crucial to improve the safety of nanomaterials and reduce associated uncertainty.</div></div><div><h3>Statement of significance</h3><div>Nanocarriers show tremendous potential for theragnostic purposes in neurological diseases, enhancing drug targeting to the brain, and improving biodistribution and pharmacokinetics. However, their neurotoxicity is still a major field to be explored, with only 5% of nanotechnology-related publications addressing this matter. This review focuses on the issue of neurotoxicity and safety assessment of nanocarriers for brain delivery. Neurotoxicity-relevant exposure sources, routes, and molecular mechanisms, along with the impact of the physicochemical properties of nanomaterials, are comprehensively described. Moreover, the different experimental models used for neurotoxicity evaluation are explored at length, including their main advantages and limitations. To conclude, we discuss current challenges and future perspectives for a better understanding of risk assessment of nanocarriers for neurobiomedical applications.</div></div>","PeriodicalId":237,"journal":{"name":"Acta Biomaterialia","volume":"189 ","pages":"Pages 25-56"},"PeriodicalIF":9.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142303137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vaginal host response to polycarbonate urethane, an alternative material for the repair of pelvic organ prolapse","authors":"Katrina Knight ,&nbsp;Sophya Breedlove ,&nbsp;Temitope Obisesan ,&nbsp;Morgan Egnot ,&nbsp;Niusha Daneshdoost ,&nbsp;Gabrielle King ,&nbsp;Leslie Meyn ,&nbsp;Ken Gall ,&nbsp;Pamela Moalli","doi":"10.1016/j.actbio.2024.09.040","DOIUrl":"10.1016/j.actbio.2024.09.040","url":null,"abstract":"<div><div>Complications following surgical repair of pelvic organ prolapse (POP) with polypropylene mesh (PPM) are common. Recent data attributes complications, in part, to stiffness mismatches between the vagina and PPM. We developed a 3D printed elastomeric membrane (EM) from a softer polymer, polycarbonate urethane (PCU). EMs were manufactured with more material given the low inherent material strength of PCU. We hypothesized that the EMs would be associated with an improved host response as compared to PPM. A secondary goal was to optimize the material distribution (fiber width and device thickness) within EMs, in regards to the host response. EM constructs (2 × 1 cm²) with varied polymer stiffness, fiber width, and device thickness were implanted onto the vagina of New Zealand white rabbits for 12 weeks and compared to similarly sized PPMs. Sham implanted animals served as controls. Mixed effects generalized linear models were used to compare the effect of construct type accounting for differences in independent variables. EMs had an overall superior host response compared to PPM as evidenced by preservation of vaginal smooth muscle morphology (<em>p</em>-values&lt;0.01), decreased total cellular response to construct fibers (<em>p</em>-values&lt;0.001), and a reduced percent of macrophages (<em>p</em>-values&lt;0.02) independent of how the material was distributed. Both PPM and EMs negatively impacted vaginal contractility and glycosaminoglycan (GAG) content relative to Sham (all <em>p</em>-values&lt;0.001) with EMs having less of an impact on GAGs (<em>p</em>-values&lt;0.003). The results suggest that softer PCU EMs made with more material are well tolerated by the vagina and comprises a future material for POP repair devices.</div></div><div><h3>Statement of significance</h3><div>Prolapse is a debilitating condition in which loss of support to the vagina causes it and the organs supported by it to descend from their normal position in the pelvis. Surgical solutions to rebuild support involves the use of polypropylene mesh which is orders of magnitude stiffer than the vagina. This mismatch results in complications including exposure of the mesh into the vagina and pain. To provide an innovative solution for women, we have developed an elastomeric membrane from a soft polymer that matches the stiffness of the vagina. Here, we show in a rabbit animal model that this device incorporates better into the vagina and is associated with an overall improved host response as compared to polypropylene mesh.</div></div>","PeriodicalId":237,"journal":{"name":"Acta Biomaterialia","volume":"189 ","pages":"Pages 298-310"},"PeriodicalIF":9.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142373683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Natural coil springs: Biomechanics and morphology of the coiled tendrils of the climbing passion flower Passiflora discophora","authors":"Frederike Klimm ,&nbsp;Marc Thielen ,&nbsp;Jaro Homburger ,&nbsp;Michelle Modert ,&nbsp;Thomas Speck","doi":"10.1016/j.actbio.2024.10.002","DOIUrl":"10.1016/j.actbio.2024.10.002","url":null,"abstract":"<div><div>Tendrils of climbing plants possess a striking spring-like structure characterized by a minimum of two helices of opposite handedness connected by a perversion. By performing tensile experiments and morphological measurements on tendrils of the climbing passion flower <em>Passiflora discophora</em>, we show that these tendril springs act as coil springs within the plant's attachment system and resemble technical coil springs. However, tendril springs have a low spring index and a high pitch angle compared with typical metal coil springs resulting in a more complex loading situation in the plant tendrils. Moreover, the tendrils undergo a drastic shift from the fresh turgescent stage to a dried-off and dead senescent stage. This entails changes in material properties (elastic modulus in tension), morphology (tendril and helix diameter, number of windings), anatomy (tissue composition), and failure behavior (susceptibility to delamination) and reduces the degree of elasticity and strain at failure of the tendrils. Nevertheless, senescent tendrils remain functional as springs and maintain high energy dissipation capacity and high break force. This renders the system highly energy efficient, as the plant no longer needs to metabolically sustain the died-back tendrils. Because of its energy-storing spring system, its high energy dissipation and high safety factor, the attachment system can be considered a ‘fail-safe’ system.</div></div><div><h3>Statement of significance</h3><div>The use of coil springs as mechanical devices is not restricted to man-made machinery; striking spring structures can also be found within the attachment systems of climbing plants. <em>Passiflora discophora</em> climbs by using long thin tendrils with adhesive pads at their tips. Once the pads have attached to a support, the tendrils coil and form a spring-like structure. Here, we analyze the form and mechanics of these ‘tendril springs’, compare them with conventional technical coil springs, and discuss changes in the tendril springs during plant development. We reveal the main features of the attachment system, which might inspire new artificial attachment devices within the emerging field of plant-inspired soft-robotics.</div></div>","PeriodicalId":237,"journal":{"name":"Acta Biomaterialia","volume":"189 ","pages":"Pages 478-490"},"PeriodicalIF":9.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142407321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Protein-metal interactions due to fretting corrosion at the taper junction of hip implants: An in vitro investigation using Raman spectroscopy","authors":"Adrian Wittrock ,&nbsp;Saskia Heermant ,&nbsp;Christian Beckmann ,&nbsp;Markus A. Wimmer ,&nbsp;Alfons Fischer ,&nbsp;Marc Aßmann ,&nbsp;Jörg Debus","doi":"10.1016/j.actbio.2024.10.006","DOIUrl":"10.1016/j.actbio.2024.10.006","url":null,"abstract":"<div><div>Modular hip implants are a clinically successful and widely used treatment for patients with arthritis. Despite ongoing retrieval studies the understanding of the fundamental physico-chemical mechanisms of friction and wear within the head-taper interface is still limited. Here, we Raman-spectroscopically analyze structural features of the biotribological material which is formed within the taper joint between Ti6Al4V and low-carbon cobalt alloy or high-nitrogen steel surfaces in <em>in vitro</em> gross-slip fretting corrosion tests with bovine calf serum. As a function of the fretting duration, we investigate short and long aliphatic chains and their adsorption behavior on the cobalt- and steel-type surfaces. Using the intensity and frequency shifts of the amide I and III Raman bands, we furthermore identify progressive protein folding and unfolding including the secondary structures of <span><math><mi>α</mi></math></span>-helix, <span><math><mi>β</mi></math></span>-sheet, and random-coil configuration as well as the formation of proteinaceous clusters depending on the hydrophilicity of the metallic surfaces. We additionally find a mixture of chromates and iron oxides with tryptophan and tyrosine at the worn cobalt alloy and high-nitrogen steel surfaces, respectively. Also, for long fretting duration, sp<span><math><msup><mrow></mrow><mn>2</mn></msup></math></span> hybridized amorphous carbon is formed due to fretting-induced cleavage of proteins.</div></div><div><h3>Statement of significance</h3><div>Despite efforts enhancing the biomedical tribology of hip implants, the impact of the organic environment on friction and wear at the femoral head-stem taper interface is limitedly understood. Using Raman spectroscopy we resolve structural changes within the biotribological material agglomerated at biomedical-grade metal alloys due to metal-organic interactions during <em>in vitro</em> fretting corrosion tests. Adsorption of short and long aliphatic chains, progressive protein (un)folding and proteinaceous cluster formation depend to a distinguishable extent on the fretting duration and type of alloy. Chromates and iron oxides are mixed with tryptophan and tyrosine, and amorphous carbon is formed resulting from a fretting-induced cleavage of serum proteins. Such information spectroscopically gleaned from biotribological material are vital to improve the design and performance of taper junctions.</div></div>","PeriodicalId":237,"journal":{"name":"Acta Biomaterialia","volume":"189 ","pages":"Pages 621-632"},"PeriodicalIF":9.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142407322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Karen L. Christman, 2025 Acta Biomaterialia Silver Medal Award Recipient","authors":"","doi":"10.1016/j.actbio.2024.07.048","DOIUrl":"10.1016/j.actbio.2024.07.048","url":null,"abstract":"","PeriodicalId":237,"journal":{"name":"Acta Biomaterialia","volume":"189 ","pages":"Page 670"},"PeriodicalIF":9.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Titanium boride nanosheets with photo-enhanced sonodynamic efficiency for glioblastoma treatment","authors":"Jiaqing Xu,&nbsp;Ying Liu,&nbsp;Han Wang,&nbsp;Junxing Hao,&nbsp;Yu Cao,&nbsp;Zhihong Liu","doi":"10.1016/j.actbio.2024.09.025","DOIUrl":"10.1016/j.actbio.2024.09.025","url":null,"abstract":"<div><div>Sonodynamic therapy (SDT) has garnered significant attention in cancer treatment, however, the low-yield reactive oxygen species (ROS) generation from sonosensitizers remains a major challenge. In this study, titanium boride nanosheets (TiB₂ NSs) with photo-enhanced sonodynamic efficiency was fabricated for SDT of glioblastoma (GBM). Compared with commonly-used TiO₂ nanoparticles, the obtained TiB₂ NSs exhibited much higher ROS generation efficiency under ultrasound (US) irradiation due to their narrower band gap (2.50 eV). Importantly, TiB₂ NSs displayed strong localized surface plasmon resonance (LSPR) effect in the second near-infrared (NIR II) window, which facilitated charge transfer rate and improved the separation efficiency of US-triggered electron–hole pairs, leading to photo-enhanced ROS generation efficiency. Furthermore, TiB₂ NSs were encapsulated with macrophage cell membranes (CM) and then modified with RGD peptide to construct biomimetic nanoagents (TiB₂@CM-RGD) for efficient blood-brain barrier (BBB) penetrating and GBM targeting. After intravenous injection into the tumor-bearing mouse, TiB₂@CM-RGD can efficiently cross BBB and accumulate in the tumor sites. The tumor growth was significantly inhibited under simultaneous NIR II laser and US irradiation without causing appreciable long-term toxicity. Our work highlighted a new type of multifunctional titanium-based sonosensitizer with photo-enhanced sonodynamic efficiency for GBM treatment.</div></div><div><h3>Statement of significance</h3><div>Titanium boride nanosheets (TiB₂ NSs) with photo-enhanced sonodynamic efficiency was fabricated for SDT of glioblastoma (GBM). The obtained TiB₂ NSs displayed strong localized surface plasmon resonance (LSPR) effect in the second near-infrared (NIR II) window, which facilitated charge transfer rate and improved the separation efficiency of US-triggered electron-hole pairs, leading to photo-enhanced ROS generation efficiency. Furthermore, TiB₂ NSs were encapsulated with macrophage cell membranes (CM) and then modified with RGD peptide to construct biomimetic nanoagents (TiB₂@CM-RGD) for efficient blood-brain barrier (BBB) penetrating and GBM targeting. After intravenous injection into the tumor-bearing mouse, TiB₂@CM-RGD can efficiently cross BBB and accumulate in the tumor sites. The tumor growth was significantly inhibited under simultaneous NIR II laser and US irradiation without causing appreciable long-term toxicity.</div></div>","PeriodicalId":237,"journal":{"name":"Acta Biomaterialia","volume":"188 ","pages":"Pages 344-357"},"PeriodicalIF":9.4,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142303142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reversible pH-switchable NIR-II nano-photosensitizer for precise imaging and photodynamic therapy of tumors","authors":"Yun Chai ,&nbsp;Ye Sun ,&nbsp;Zhijia Sheng ,&nbsp;Yanyan Zhu ,&nbsp;Tianyou Du ,&nbsp;Bingjian Zhu ,&nbsp;Hui Yu ,&nbsp;Bin Dong ,&nbsp;Yi Liu ,&nbsp;Hai-Yan Wang","doi":"10.1016/j.actbio.2024.09.001","DOIUrl":"10.1016/j.actbio.2024.09.001","url":null,"abstract":"<div><div>Photodynamic therapy (PDT) has attracted widespread attention from researchers as an emerging cancer treatment method. There have been many reports on various types of NIR-II photosensitizers for imaging and treatment of tumor sites. However, there are few reports on the development of NIR-II organic small molecule photosensitizers that have intelligent response to the tumor microenvironment, precise imaging, real-time treatment, and high biocompatibility. In this work, we developed a series of NIR-II photosensitizers (RBTs) with near-infrared excitation, good photostability, and large Stokes shift. Among them, RBT-Br exhibited higher reactive oxygen species (ROS) generation efficiency due to the introduction of halogen heavy atoms to enhance intersystem crossing (ISC). It is noteworthy that RBT-Br can generate singlet oxygen (¹O₂) and superoxide anion radicals (^•O₂⁻) simultaneously under 730 nm laser. Subsequently, we used molecular engineering technology to construct three pH-responsive NIR-II photosensitizers (RBT-pHs) by utilizing the closure of the lactam ring, among which RBT-pH-1 (p<em>K</em>_a = 6.78) is able to be directionally activated under the stimulation of tumor micro-acid environment, with its fluorescence emission window reaching 933 nm. Subsequently, RBT-pH-1 NPs encapsulated in DSPE-mPEG_5k were applied for PDT treatment of mouse tumors. The results showed that RBT-pH-1 NPs were activated by the acidic tumor microenvironment and generated ROS under laser excitation, exhibiting precise tumor imaging and significant tumor growth inhibition. We look forward to these multifunctional NIR-II organic small molecule photosensitizers providing a more efficient approach for clinical treatment of tumors.</div></div><div><h3>Statement of significance</h3><div>A reversible pH-switchable NIR-II nano-photosensitizer RBT-pH-1 NPs (p<em>K</em>_a = 6.76) is developed for precise imaging and PDT therapy of mouse tumors, which can be effectively used for targeted enrichment and activation of tumor micro-acid environments. The results show that this NIR-II photosensitizer generates ROS through tumor micro-acid environment stimulation and laser triggering, showing precise tumor imaging guidance and significant tumor growth inhibition.</div></div>","PeriodicalId":237,"journal":{"name":"Acta Biomaterialia","volume":"188 ","pages":"Pages 315-328"},"PeriodicalIF":9.4,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142147080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural connectivity and bioactivity in sol–gel silicate glass design","authors":"Chisokwuo Akunna,&nbsp;Marta Cerruti","doi":"10.1016/j.actbio.2024.08.030","DOIUrl":"10.1016/j.actbio.2024.08.030","url":null,"abstract":"<div><div>Bioactive glasses (BGs) bond with bone by forming hydroxy carbonate apatite (HCA) upon reaction in physiological fluid, a phenomenon known as bioactivity. BGs structural network connectivity determines their bioactivity. Sol–gel BGs are synthesized through the hydrolysis and condensation of metal alkoxide precursors in the presence of a catalyst, in aqueous environments. Several sol–gel synthesis parameters directly impact BG network connectivity: pH (i.e. acid or basic catalysis), water to alkoxide ratio (R_w), alkoxide type and presence of dopant ions. However, the relationship between bioactivity and these parameters remains surprisingly unexplored.</div><div>This study highlights the relationship between synthesis pH, R_w, network connectivity and bioactivity in silica-based sol-gel BGs and BGs doped with titanium (Ti) ions (TiBGs), the latter selected for their known ability to enhance network connectivity. BGs and TiBGs are synthesized with various R_w values under acidic and basic conditions, and their bioactivity is assessed in simulated body fluid for 7 days.</div><div>Increasing R_w decreases network connectivity and increases bioactivity of BGs with high network connectivity, as observed for base-catalyzed BGs and for both acid and base catalyzed TiBGs, but not in BGs with lower connectivity as evidenced in acid-catalyzed BGs. Basic catalysis of TiBGs prevents crystalline TiO₂ domain formation, which was instead consistently observed in TiBGs synthesized under acidic catalysis.</div><div>These findings help the design of BGs for applications where ion release needs to be enhanced even in the presence of dopants that slow down HCA formation, and of BGs with specific properties, e.g. TiO₂-containing BGs with potential bactericidal activity.</div></div><div><h3>Statement of significance</h3><div>Bioactive glasses (BGs) bond with bone by dissolving and forming hydroxycarbonate apatite (HCA) on their surface, offering applications in medicine and dentistry. BG's network connectivity influences its dissolution rate, and hence HCA formation. While solution-gelation (sol-gel) is commonly used for BG production, the effect of sol gel synthesis parameters on HCA formation remains unexplored. We studied the relationship between synthesis parameters (water-to-alkoxide ratio (R_w), catalyst, and dopant ions, particularly titanium), BG network connectivity, and HCA formation. We find that increasing R_w with any catalyst enhances HCA formation, particularly in glasses with high network connectivity. This understanding allows tailoring BG synthesis for different applications, e.g. those requiring doping with ions that increase network connectivity and fills a crucial gap in BG literature.</div></div>","PeriodicalId":237,"journal":{"name":"Acta Biomaterialia","volume":"188 ","pages":"Pages 374-392"},"PeriodicalIF":9.4,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142057489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated data-driven discovery of material models based on symbolic regression: A case study on the human brain cortex","authors":"Jixin Hou ,&nbsp;Xianyan Chen ,&nbsp;Taotao Wu ,&nbsp;Ellen Kuhl ,&nbsp;Xianqiao Wang","doi":"10.1016/j.actbio.2024.09.005","DOIUrl":"10.1016/j.actbio.2024.09.005","url":null,"abstract":"<div><div>We introduce a data-driven framework to automatically identify interpretable and physically meaningful hyperelastic constitutive models from sparse data. Leveraging symbolic regression, our approach generates elegant hyperelastic models that achieve accurate data fitting with parsimonious mathematic formulas, while strictly adhering to hyperelasticity constraints such as polyconvexity/ellipticity. Our investigation spans three distinct hyperelastic models—invariant-based, principal stretch-based, and normal strain-based—and highlights the versatility of symbolic regression. We validate our new approach using synthetic data from five classic hyperelastic models and experimental data from the human brain cortex to demonstrate algorithmic efficacy. Our results suggest that our symbolic regression algorithms robustly discover accurate models with succinct mathematic expressions in invariant-based, stretch-based, and strain-based scenarios. Strikingly, the strain-based model exhibits superior accuracy, while both stretch-based and strain-based models effectively capture the nonlinearity and tension-compression asymmetry inherent to the human brain tissue. Polyconvexity/ellipticity assessment affirm the rigorous adherence to convexity requirements both within and beyond the training regime. However, the stretch-based models raise concerns regarding potential convexity loss under large deformations. The evaluation of predictive capabilities demonstrates remarkable interpolation capabilities for all three models and acceptable extrapolation performance for stretch-based and strain-based models. Finally, robustness tests on noise-embedded data underscore the reliability of our symbolic regression algorithms. Our study confirms the applicability and accuracy of symbolic regression in the automated discovery of isotropic hyperelastic models for the human brain and gives rise to a wide variety of applications in other soft matter systems.</div></div><div><h3>Statement of significance</h3><div>Our research introduces a pioneering data-driven framework that revolutionizes the automated identification of hyperelastic constitutive models, particularly in the context of soft matter systems such as the human brain. By harnessing the power of symbolic regression, we have unlocked the ability to distill intricate physical phenomena into elegant and interpretable mathematical expressions. Our approach not only ensures accurate fitting to sparse data but also upholds crucial hyperelasticity constraints, including polyconvexity, essential for maintaining physical relevance.</div></div>","PeriodicalId":237,"journal":{"name":"Acta Biomaterialia","volume":"188 ","pages":"Pages 276-296"},"PeriodicalIF":9.4,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142303127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}