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Small‐molecular‐weight (MW) additives can strongly impact amorphous calcium carbonate (ACC), playing an elusive role in biogenic, geologic, and industrial calcification. Here, we present molecular mechanisms by which these additives regulate stability and composition of both CaCO3 solutions and solid ACC. Potent antiscalants inhibit ACC precipitation by interacting with prenucleation clusters (PNCs); they specifically trigger and integrate into PNCs or feed PNC growth actively. Only PNC‐interacting additives are traceable in ACC, considerably stabilizing it against crystallization. The selective incorporation of potent additives in PNCs is a reliable chemical label that provides conclusive chemical evidence that ACC is a molecular PNC‐derived precipitate. Our results reveal additive‐cluster interactions beyond established mechanistic conceptions. They reassess the role of small‐MW molecules in crystallization and biomineralization while breaking grounds for new sustainable antiscalants.

Biomineralizing organisms are widely praised for their ability to generate structural materials with exceptional crystallographic control. While earlier studies highlighted near-to single-crystalline biominerals, complex polycrystalline features are more widespread yet challenging to account for. Here, we propose that biominerals whose crystal texture varies with depth are functionally graded materials. Using the exemplary case of the nacro-prismatic pearl oyster Pinctada margaritifera, we demonstrate systematic textural changes in a biogenic ceramic. This bivalve employs three synergistic mechanisms to generate a texture gradient across its outer calcitic shell layer. This prismatic layer transitions from an initially weakly-textured to a strongly-textured material. Such changes in texture cause a variation in Young's modulus normal to the shell, owing to the anisotropic mechanical properties of the composing crystallites. Based on finite-element simulations and indentation experiments on the bivalve shell, we conclude that such graded bioceramics yield intrinsic toughening properties similar to those found in compositionally-graded synthetic materials. Notwithstanding, the gradation concept of Pinctada margaritifera is unparalleled among synthetic materials as it rests solely upon elastic anisotropy, making oyster shells potential blueprints for future bioinspired functional materials and damage-resistant ceramics.

Small-molecular-weight (MW) additives can strongly impact amorphous calcium carbonate (ACC), playing an elusive role in biogenic, geologic, and industrial calcification. Here, we present molecular mechanisms by which additives regulate stability and composition of both CaCO3 solutions and solid ACC. Potent antiscalants inhibit ACC precipitation by interacting with prenucleation clusters (PNC); they specifically trigger and integrate into PNCs or feed PNC growth. Only PNC-interacting additives are traceable in ACC, considerably stabilizing it against crystallization. The selective incorporation of potent additives in PNCs is a reliable chemical label that provides conclusive chemical evidence that ACC is a molecular precipitate derived PNCs. Our results reveal additive-cluster interactions beyond established mechanistic conceptions. They reassess the role of small-MW molecules in crystallization and biomineralization, while breaking grounds for new sustainable antiscalants.

Small-molecular-weight (MW) additives can strongly impact amorphous calcium carbonate (ACC), playing an elusive role in biogenic, geologic, and industrial calcification. Here, we present molecular mechanisms by which additives regulate stability and composition of solid ACC and CaCO3 solutions simultaneously. Effective precipitation inhibition arises from pronounced interaction of additives with prenucleation clusters (PNC). Potent antiscalants specifically trigger and integrate into PNCs. Only PNC-interacting additives are traceable in solid ACC, considerably stabilizing ACC against transformation. This co-precipitation specificity facilitates a chemical labeling of PNCs, evidencing ACC as a molecular precipitate of PNCs. Our results reveal additive-cluster interactions that operate beyond established mechanistic conceptions and thus reassess the role of small-MW molecules in crystallization and especially in biomineralization while breaking grounds for new sustainable antiscalants.

Primary lymphomas of the central nervous system (PCNSL) are mainly diffuse large B-cell lymphomas (DLBCLs) confined to the central nervous system (CNS). Despite extensive research, the molecular alterations leading to PCNSL have not been fully elucidated. In order to provide a comprehensive description of the genomic and transcriptional landscape of PCNSL, we here performed whole-genome and transcriptome sequencing and integrative analysis of 51 lymphomas presenting in the CNS, including 42 EBV-negative PCNSL, 6 secondary CNS lymphomas (SCNSL) and 3 EBV+ CNSL and matched controls. The results were compared to an independent validation cohort of 31 FFPE CNSL specimens (PCNSL, n = 19; SCNSL, n = 9; EBV+ CNSL, n = 3) as well as 39 FL and 36 systemic DLBCL cases outside the CNS. Somatic genomic alterations in PCNSL mainly affect the JAK-STAT, NFkB, and B-cell receptor signaling pathways, with hallmark recurrent mutations including MYD88 L265P (67%) and CD79B (63%), CDKN2A deletions (83%) and also non-coding RNA genes such as MALAT1 (70%), NEAT (60%), and MIR142 (80%). Kataegis events, which affected 15 of 50 identified driver genes and 21 of the top 50 mutated ncRNAs, played a decisive role in shaping the mutational repertoire of PCNSL. Compared to systemic DLBCL, PCNSLs exhibited significantly more focal deletions in 6p21 targeting the HLA-D locus that encodes for MHC class II molecules as a potential mechanism of immune evasion. Mutational signatures correlating with DNA replication and mitosis (SBS1, ID1 and ID2) were significantly enriched in PCNSL (SBS1: p = 0.0027, ID1/ID2: p < 1×10−4). Furthermore, TERT gene expression was significantly higher in PCNSL compared to ABC-DLBCL (p = 0.027). Although PCNSL share many genetic alterations with systemic ABC-DLBCL in the same signaling pathways, transcriptome analysis clearly distinguished both into distinct molecular subtypes. EBV+ CNSL cases may be distinguished by lack of recurrent mutational hotspots apart from IG and HLA-DRB loci.

Here, we approach the issue of ACC ultrastructure by applying a method for determining atomically resolved structures of amorphous materials using Monte Carlo simulations constrained by both X-ray and neutron scattering data. This structural analysis approach allows us to develop a detailed model for ACC at the atomic level. Our findings reveal that synthetic ACC, rapidly precipitated at high pH, consists of two-nanometer sized units containing a high degree of near range order similar to partially disordered nano-crystals. Small-angle scattering analyses show a multi-scale hierarchical organisation of the structure, supportive of a multi-step colloid self-assembly process. Computer simulations and high-resolution transmission electron microscopy show that the mesostructure of ACC resembles that of a glassy gel with crystalline material in domains. Our findings support the formation of ACC by a nanoparticle aggregation process that likely starts from prenucleation clusters in solution.

Biominerals are bioinorganic solid-state materials generated by organisms under mildest and sustainable conditions. These biogenic materials serve the host organism for vital functions, having undergone more than half a billion years of evolutionary optimization for function, resilience, energy efficiency, and endurance. The research field of biomineralization is a highly interdisciplinary field, contributing to life sciences, Earth sciences, and materials sciences. On the molecular level, biomineralization turns into a chemical discipline, a new branch of bioinorganic chemistry. It is a major task of bioinorganic solid-state chemistry to provide answers to the fundamental question of how organisms can exert such an exceptional level of control over the formation of an inorganic solid-state and to exploit the newly identified synthesis concepts for novel and biomimetic materials and synthesis processes. Herein, we will explore this new branch of bioinorganic chemistry, which thrives alongside the well-established and flourishing branch of biocoordination chemistry. We will review pertinent examples of biomineralization and fathom how their analysis and our mimesis attempts were capable of transforming our current conceptional knowledge on the genesis of solid-state material from solution and led to new and nonclassical crystallization concepts.

Calcium carbonate cements are a promising alternative for calcium phosphate cements. Due to the higher solubility of calcium carbonate compared to apatite, it is expected to have an improved biodegradation rate; a clear advantage for prospective biomedical applications in a clinical context. As of yet, the poor mechanical performance of calcium carbonate cements precludes their exploitation as a bioceramic. Herein, we report a mechanically enhanced calcium carbonate cement, formulated of vaterite and magnesium-doped amorphous calcium carbonate, which was strengthened by in situ polymerization of incorporated 2-hydroxyethylmethacrylate (HEMA) during setting in simulated body fluid (SBF). This approach allowed us to generate a pronouncedly strengthened polymer-ceramic composite whose mechanical properties can be tuned by the monomer fraction. Varying cement compositions were characterized with respect to their mechanical performance, morphology, and quantitative phase composition. HEMA polymer reinforcement strengthened the calcium carbonate cement distinctly in four-point bending test while, in stark contrast, the brittleness of the polymer-free cement simply made such tests impossible. Our results demonstrate that the chosen polymer-enforcement strategy is an efficient and straightforward approach and allows for tuning the mechanical properties of an otherwise brittle and thus unusable calcium carbonate cement towards biomedical application.

Nonclassical crystallization typically yields materials with pronounced roughness and porosity as it is driven by nanoparticle self-organization. Here, we demonstrate that bio-inspired nonclassical mineralization via magnesium-doped polymer-induced liquid precursors (PILP) can yield ultra-smooth and space-filling CaCO3 films featuring an unprecedented low roughness of 0.285 nm.

Calcium carbonate is an abundant biomineral, and already archeological records demonstrate its bioactivity and applicability for osseo-integrative implants. Its solubility, which is generally higher than those of calcium phosphates, depends on its polymorph turning calcium carbonate into a promising biomaterial with tunable bioresorption rate. However, the phase-dependent bioactivity of calcium carbonate, i.e., its osteoconductivity, is still insufficiently characterized. In this study, we address this issue by monitoring the behavior of the four most important calcium carbonate phases, i.e., calcite, aragonite, vaterite, and amorphous calcium carbonate, in simulated body fluid solution at 37 °C. Our results demonstrate that the thermodynamically stable calcite phase is essentially inert. In contrast, the metastable phases aragonite and vaterite are bioactive, thus promoting the formation of calcium phosphate. Amorphous calcium carbonate (ACC) shows prominent bioactivity accompanied by pronounced redissolution processes. Mg-stabilized ACC was additionally tested since its increased stability eases formulation and handling in future applications. It is highly bioactive and, moreover, the additional release of Mg promotes cell viability. Overall, our results demonstrate that bioactivity of calcium carbonate is phase-dependent, allowing tailored response and bioactivity of future calcareous biomaterials. Our results also reveal that phosphate ions strongly interfere with Ostwald–Lussac step ripening of calcium carbonate, kinetically stabilizing metastable polymorphs such as vaterite and aragonite; this is a distinctive feature of the calcium carbonate mineral system which clearly has to be considered in future applications of calcium carbonate as a bioceramic.

The formation of a solid-state material from solution is a ubiquitous process of fundamental importance not only for synthesis in solid-state chemistry but for a wide range of disciplines such as geosciences and biology. However, established classical crystallization theories fall short in explaining the outcome of crystallization and mineralization processes in complex environments, such as in biomineralizing organisms or geochemical and industrial settings. The misfit between classical textbook knowledge and the plurality of conflicting experimental evidence facilitated the advent of an array of new crystallization concepts. These so-called nonclassical crystallization processes are fuelled by the attachment of multiatomic assemblies rather than by attachment of single ions drive crystal formation. Some of these models, such as oriented attachment, were unequivocally backed by experimental evidence and thus accepted by the science community. Other models have encountered distinct resistance from peers. At the centre of this intense dispute, we find the calcium carbonate system, which is of crucial importance for a range of disciplines. For this system, in particular, the existence of prenucleation clusters in the form of dynamically ordered liquid-like polyoxoanions (DOLLOP) has been suggested, and it has been claimed that nonclassical nucleation processes take place. However several groups have challenged this claim, claiming an entirely classical crystallization behaviourBased on our results, we will draw a different picture of calcium carbonate formation. We show that the issues with this very systems root in its solute chemistry and the fact that this renders a calcium carbonate solution into a multicomponent system. We show liquid-liquid phase separation of near-neutral calcium carbonate solutions along with the first ultrastructural model of amorphous calcium carbonate (ACC). This findings give insight into the formation mechanisms of calcium carbonate under kinetically controlled conditions. Our findings further demonstrate that the formation of a liquid-condensed mineral precursor phase is not solely a “quirk of the peculiar calcium carbonate system” but a general phenomenon: it is an early stage precursor in the formation pathway of calcium carbonate under geo- and biochemical relevant conditions. Moreover, we show that this unexpected demixing behaviour is widespread, many inorganic components go through spinodal decomposition, when the reaction conditions are kinetically controlled and the solution chemistry disadvantage burst nucleation. Our data suggest that it is not the misconception and oversimplification of classical theories but our oversimplification of the solution chemistry which causes the current dispute on classical vs nonclassical nucleation of inorganic compounds. Currently, we see no need for invoking “non-classical” notions of nucleation since our exceptional observations can entirely be explained by established physicochemical concepts apart from CNT. Our results raise the awareness that a supramolecular solution and coordination chemistry provides the key to a thorough understanding of the genesis of inorganic solids under kinetically controlled conditions.

Correction for ‘Progressive changes in crystallographic textures of biominerals generate functionally graded ceramics’ by David Wallis et al., Mater. Adv., 2022, DOI: 10.1039/d1ma01031j.

For bioactive biomaterials such as bioceramics and bioglass, it is generally accepted that, apart from acting as heterogeneous nucleators, it is their solubility and the resulting release of relevant ions such as calcium or basic anions which mainly governs the biomaterial’s bioactivity. This contribution reveals that this bioactivity, as assessed by simulated body fluid (SBF), can also be considerably modified by the bioceramic’s morphology, i.e., bioactivity is also governed by microstructure and surface morphology. When crystals are forced to adopt out-of-equilibrium crystal habit, this simple change in morphology converts an essentially bioinert material, here calcite, into a bioceramic which shows bioactivity in SBF. On larger length scales, already simple morphological changes, such as scratches, can have inverse effects. Limited mass transport into grooves and pits on a bioceramic surface can lead to local ion depletion which, in turn, causes reduced bioactivity of bioceramics which, otherwise, show distinct bioactivity in SBF. This contribution emblematically illustrates the unforeseen importance of even minor morphology changes on different length scales when assessing and designing a biomaterial’s bioactivity through SBF assays.

The remarkable mechanical performance of biominerals often relies on distinct crystallographic textures, which complicate the determination of the nanohardness from indentations with the standard non-rotational-symmetrical Berkovich punch. Due to the anisotropy of the biomineral to be probed, an azimuthal dependence of the hardness arises. This typically increases the standard deviation of the reported hardness values of biominerals and impedes comparison of hardness values across the literature and, as a result, across species. In this paper, we demonstrate that an azimuthally independent nanohardness determination can be achieved by using a conical indenter. It is also found that conical and Berkovich indentations yield slightly different hardness values because they result in different pile-up behaviors and because of technical limitations on the fabrication of perfectly equivalent geometries. For biogenic crystals, this deviation of hardness values between indenters is much lower than the azimuthal variation in non-rotational-symmetrical Berkovich indentations.

Chordomas are rare bone tumors with few therapeutic options. Here we show, using whole-exome and genome sequencing within a precision oncology program, that advanced chordomas (n = 11) may be characterized by genomic patterns indicative of defective homologous recombination (HR) DNA repair and alterations affecting HR-related genes, including, for example, deletions and pathogenic germline variants of BRCA2, NBN, and CHEK2. A mutational signature associated with HR deficiency was significantly enriched in 72.7% of samples and co-occurred with genomic instability. The poly(ADP-ribose) polymerase (PARP) inhibitor olaparib, which is preferentially toxic to HR-incompetent cells, led to prolonged clinical benefit in a patient with refractory chordoma, and whole-genome analysis at progression revealed a PARP1 p.T910A mutation predicted to disrupt the autoinhibitory PARP1 helical domain. These findings uncover a therapeutic opportunity in chordoma that warrants further exploration, and provide insight into the mechanisms underlying PARP inhibitor resistance., Chordomas are rare bone tumors with limited therapeutic options. Here, the authors identify molecular alterations associated with defective homologous recombination DNA repair in advanced chordomas and report prolonged response in a patient treated with a PARP inhibitor, which later acquired resistance due to a newly gained PARP1 mutation.

11 pages; International audience; The structural organization of the palliostracum—the dominant part of the shell which is formed by the mantle cells—of Glycymeris glycymeris (Linné 1758) is comprised of five hierarchical levels with pronounced structural commonalities and deviations from other crossed-lamellar shells. The hierarchical level known as second order lamellae, present within other crossed-lamellar shells, is absent highlighting a short-coming of the currently used nomenclature. On the mesoscale, secondary microtubules penetrate the palliostracum and serve as crack arrestors. Moreover, the growth lamellae follow bent trajectories possibly impacting crack propagation, crack deflection, and energy dissipation mechanisms whilst circumventing delamination. Finally, at least two structural elements are related to external circatidal and circaanular stimuli. This emphasizes that endogeneous rhythms may contribute and (co-)control the self-organization of a complex mineralized tissue and that it is insufficient to rely fully on a reductionistic approach when studying biomineralization.

The surface modification of aramid fibers is an essential and potent approach to manipulate and improve fiber properties. Biogenic fibers are in stark contrast, as exemplified by the case of natural silk fibers. This high-performance fiber features a surface functionalization as a thin sericin film enwraps it for improving the mechanical properties of silks. Inspired by this unique sheath structure of biogenic silk, we improved the performance of aramid fibers by exploiting a coating composed of reduced graphene oxide nanosheets that self-assemble on the fiber surface guided by hydrogen bonding and π-π stacking interactions. The graphene functionalized aramid fibers show a remarkable 1 GPa improvement in tensile strength. Moreover, the functionalized aramid fiber also shows high electrical conductivity which preserved 99% of its conductivity even after 100 cycles. Our approach provides a universal strategy for improving the performance of the fiber via surface functionalization by graphene nanosheets.

Governing polymorph selection is a crucial issue in the pharmaceutical, food, and fine chemical industry. However, the multiple stages during the formation of the polymorphic crystals from solution and the concurrent processes selecting the final polymorph are still unclear. In this study, we demonstrate the existence of hydrated amorphous intermediates in the early stages of separation of organic crystal L-glutamic acid where the nucleation of crystalline metastable α-form spontaneously occurred within these intermediates, leading to the formation of odd-shaped and intergrown crystal aggregates. Further, we found that these amorphous intermediates severed not only as a transient intermediate in a nucleation process, but they also co-determined the size distribution, mean particle size, and phase transformation rates of polymorphic L-glutamic acid.

The combination of soft nanoscale organic components with inorganic nanograins hierarchically designed by natural organisms results in highly ductile structural materials that can withstand mechanical impact and exhibit high resilience on the macro- and nano-scale. Our investigation of nacre deformation reveals the underlying nanomechanics that govern the structural resilience and absorption of mechanical energy. Using high-resolution scanning/transmission electron microscopy (S/TEM) combined with in situ indentation, we observe nanoscale recovery of heavily deformed nacre that restores its mechanical strength on external stimuli up to 80% of its yield strength. Under compression, nacre undergoes deformation of nanograins and non-destructive locking across organic interfaces such that adjacent inorganic tablets structurally join. The locked tablets respond to strain as a continuous material, yet the organic boundaries between them still restrict crack propagation. Remarkably, the completely locked interface recovers its original morphology without any noticeable deformation after compressive contact stresses as large as 1.2 GPa., 4 figures

Natural nacre exhibits extraordinary functional and structural diversity, combining high strength and toughness. The mechanical properties of nacre are attributed to (i) a highly arranged hierarchical layered structure of inorganic minerals (95 vol %) containing a small amount only of organic materials (5 vol %), (ii) abundant synergistic interfacial interactions, and (iii) formation under ambient temperature. Herein, inspired by these three design principles originating from natural nacre, the supertough bioinspired graphene-based nanocomposite fibers (BGNFs) are prepared under room temperature via sequential interfacial interactions of ionic bonding and π-π interactions. The resultant synergistic effect leads to a super toughness of 18.7 MJ m-3 as well as a high tensile strength of 740.1 MPa. In addition, the electrical conductivity of these supertough BGNFs is as high as 384.3 S cm-1. They can retain almost 80% of this conductivity even after 1000 cycles of loading-unloading testing, which makes these BGNFs promising candidates for application in flexible and stable electrical devices, such as strain sensors and actuators.

The biomineral phase of avian eggshell is characterized at the nanostructure scale and correlated with functional properties., Avian (and formerly dinosaur) eggshells form a hard, protective biomineralized chamber for embryonic growth—an evolutionary strategy that has existed for hundreds of millions of years. We show in the calcitic chicken eggshell how the mineral and organic phases organize hierarchically across different length scales and how variation in nanostructure across the shell thickness modifies its hardness, elastic modulus, and dissolution properties. We also show that the nanostructure changes during egg incubation, weakening the shell for chick hatching. Nanostructure and increased hardness were reproduced in synthetic calcite crystals grown in the presence of the prominent eggshell protein osteopontin. These results demonstrate the contribution of nanostructure to avian eggshell formation, mechanical properties, and dissolution.

Employing the widely used ammonium carbonate diffusion method, we demonstrate that altering an extrinsic parameter—desiccator size—which is rarely detailed in publications, can alter the route of crystallization. Hexagonally packed assemblies of spherical magnesium-calcium carbonate particles or spherulitic aragonitic particles can be selectively prepared from the same initial reaction solution by simply changing the internal volume of the desiccator, thereby changing the rate of carbonate addition and consequently precursor formation. This demonstrates that it is not merely the quantity of an additive which can control particle morphogenesis and phase selectivity, but control of other often ignored parameters are vital to ensure adequate reproducibility.

Leiomyosarcoma (LMS) is an aggressive mesenchymal malignancy with few therapeutic options. The mechanisms underlying LMS development, including clinically actionable genetic vulnerabilities, are largely unknown. Here we show, using whole-exome and transcriptome sequencing, that LMS tumors are characterized by substantial mutational heterogeneity, near-universal inactivation of TP53 and RB1, widespread DNA copy number alterations including chromothripsis, and frequent whole-genome duplication. Furthermore, we detect alternative telomere lengthening in 78% of cases and identify recurrent alterations in telomere maintenance genes such as ATRX, RBL2, and SP100, providing insight into the genetic basis of this mechanism. Finally, most tumors display hallmarks of “BRCAness”, including alterations in homologous recombination DNA repair genes, multiple structural rearrangements, and enrichment of specific mutational signatures, and cultured LMS cells are sensitive towards olaparib and cisplatin. This comprehensive study of LMS genomics has uncovered key biological features that may inform future experimental research and enable the design of novel therapies., The molecular genetic landscape of leiomyosarcoma (LMS) is largely unknown. Here, the authors identify frequent DNA copy number alterations, whole-genome duplication, TP53 and RB1 inactivation, alternative telomere lengthening, and genomic imprints of defective DNA repair via homologous recombination as a potential therapeutic target in LMS patients.

Biominerals are typically indispensable structures for their host organism in which they serve varying functions, such as mechanical support and protection, mineral storage, detoxification site, or as a sensor or optical guide. In this perspective article, we highlight the occurrence of both structural diversity and uniformity within these biogenic ceramics. For the first time, we demonstrate that the universality–diversity paradigm, which was initially introduced for proteins by Buehler et al . (Cranford & Buehler 2012 Biomateriomics ; Cranford et al. 2013 Adv. Mater. 25 , 802–824 ( doi:10.1002/adma.201202553 ); Ackbarow & Buehler 2008 J. Comput. Theor. Nanosci. 5 , 1193–1204 ( doi:10.1166/jctn.2008.001 ); Buehler & Yung 2009 Nat. Mater. 8 , 175–188 (doi:10.1038/nmat2387)), is also valid in the realm of biomineralization. A nanogranular composite structure is shared by most biominerals which rests on a common, non-classical crystal growth mechanism. The nanogranular composite structure affects various properties of the macroscale biogenic ceramic, a phenomenon we attribute to emergence. Emergence, in turn, is typical for hierarchically organized materials. This is a clear call to renew comparative studies of even distantly related biomineralizing organisms to identify further universal design motifs and their associated emergent properties. Such universal motifs with emergent macro-scale properties may represent an unparalleled toolbox for the efficient design of bioinspired functional materials.

Nature successfully employs inorganic solid-state materials (i.e., biominerals) and hierarchical composites as sensing elements, weapons, tools, and shelters. Optimized over hundreds of millions of years under evolutionary pressure, these materials are exceptionally well adapted to the specifications of the functions that they perform. As such, they serve today as an extensive library of engineering solutions. Key to their design is the interplay between components across length scales. This hierarchical design—a hallmark of biogenic materials—creates emergent functionality not present in the individual constituents and, moreover, confers a distinctly increased functional density, i.e., less material is needed to provide the same performance. The latter aspect is of special importance today, as climate change drives the need for the sustainable and energy-efficient production of materials. Made from mundane materials, these bioceramics act as blueprints for new concepts in the synthesis and morphosynthesis of multifunctional hierarchical materials under mild conditions. In this review, which also may serve as an introductory guide for those entering this field, we demonstrate how the pursuit of studying biomineralization transforms and enlarges our view on solid-state material design and synthesis, and how bioinspiration may allow us to overcome both conceptual and technical boundaries.

Chordomas are rare tumors of the axial skeleton and skull base with few therapeutic options and no clinically validated molecular drug targets. The value of comprehensive genomic analyses for guiding medical therapy of patients with advanced-stage chordoma is unknown. We performed whole-exome and genome sequencing of tumor and matched germline control samples from 11 patients with locally advanced or metastatic chordoma within the MASTER program, a prospective clinical sequencing program of the German Cancer Consortium. All patients were pretreated and had progressive disease prior to molecular analysis. Genomic profiling showed that advanced chordomas are frequently characterized by genomic patterns indicative of defective homologous recombination (HR) DNA repair. First, DNA copy number profiles showed high numbers of structural variants greater than 10 million base pairs in size in the majority of cases. Second, all patients harbored somatic aberrations of at least 2 genes known to be involved in HR, and 10/11 cases harbored somatic alterations in 3 or more HR pathway genes. For example, 8 patients showed heterozygous BRCA2 deletions, which were associated with heterozygous deletions of ERCC6 in 6 patients and RAD54L in 7 patients, as well as PTEN alterations (heterozygous deletion, heterozygous mutation and deletion of the wildtype allele or loss of heterozygosity). Other recurrently altered HR genes included ATR, CHEK2, FANCC, FANCD2, FANCG, RAD18, RAD51B, and XRCC3. Third, pathogenic germline alterations were detected in 3 patients. A heterozygous BRCA2 frameshift mutation (p.T3085fs*26; ACMG Class 5), a heterozygous NBN frameshift mutation (p.K219Nfs*16; ACMG Class 5), and a heterozygous CHEK2 missense mutation (p.R145W; ACMG Class 4) were accompanied by somatic deletion of the respective wildtype alleles. Fourth, a mutational signature associated with HR deficiency was significantly enriched in 72.7% of samples and coincided with genomic instability. The high prevalence of an HR deficiency “footprint” in chordoma patients prompted us to explore the clinical efficacy of the poly(ADP-ribose) polymerase(PARP) inhibitor olaparib, which is preferentially toxic to HR-incompetent cells. Olaparib treatment of a patient whose tumor showed a prominent exposure to an HR deficiency-associated mutational signature, a high degree of genomic instability, and 13 heterozygous HR gene alterations halted tumor growth for 10 months. Whole-genome analysis at progression revealed a PARP1 p.T910A mutation predicted to disrupt the autoinhibitory PARP1 helical domain, providing novel insight into the mechanisms of PARP inhibitor resistance. In summary, our study has uncovered a key biological feature of advanced chordoma that represents an immediately actionable therapeutic target and provides a rationale for genomics-guided clinical trials of PARP inhibition in this intractable tumor entity. Citation Format: Stefan Gröschel, Daniel Hübschmann, Francesco Raimondi, Peter Horak, Gregor Warsow, Martina Fröhlich, Barbara Klink, Laura Gieldon, Barbara Hutter, Kortine Kleinhenz, David Bonekamp, Oliver Marschal, Priya Chudasama, Jagoda Mika, Marie Groth, Sebastian Uhrig, Stephen Krämer, Christoph Heining, Christoph Heilig, Daniela Richter, Eva Reisinger, Katrin Pfütze, Roland Eils, Stephan Wolf, Christof von Kalle, Christian Brandts, Claudia Scholl, Wilko Weichert, Stephan Richter, Sebastian Bauer, Roland Penzel, Evelin Schröck, Albrecht Stenzinger, Richard Schlenk, Benedikt Brors, Robert Russell, Hanno Glimm, Matthias Schlesner, Stefan Fröhling. Defective homologous recombination DNA repair as therapeutic target in advanced chordoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2723.

Calcareous biominerals typically feature a hybrid nanogranular structure consisting of calcium carbonate nanograins coated with organic matrices. This nanogranular organisation has a beneficial effect on the functionality of these bioceramics. In this feasibility study, we successfully employed a flow-chemistry approach to precipitate Mg-doped amorphous calcium carbonate particles functionalized by negatively charged polyelectrolytes&mdash, either polyacrylates (PAA) or polystyrene sulfonate (PSS). We demonstrate that the rate of Mg incorporation and, thus, the ratio of the Mg dopant to calcium in the precipitated amorphous calcium carbonate (ACC), is flow rate dependent. In the case of the PAA-functionalized Mg-doped ACC, we further observed a weak flow rate dependence concerning the hydration state of the precipitate, which we attribute to incorporated PAA acting as a water sorbent, a behaviour which is not present in experiments with PSS and without a polymer. Thus, polymer-dependent phenomena can affect flow-chemistry approaches, that is, in syntheses of functionally graded materials by layer-deposition processes.

Sinonasal carcinomas (SNCs) comprise various rare tumor types that are characterized by marked histologic diversity and largely unknown molecular profiles, yet share an overall poor prognosis owing to an aggressive clinical course and frequent late-stage diagnosis. The lack of effective systemic therapies for locally advanced or metastatic SNC poses a major challenge to therapeutic decision making for individual patients. We here aimed to identify actionable genetic alterations in a patient with metastatic SNC whose tumor, despite all diagnostic efforts, could not be assigned to any known SNC category and was refractory to multimodal therapy.We used whole-exome and transcriptome sequencing to identify a KIT exon 11 mutation (c.1733_1735del, p.D579del) as potentially druggable target in this patient and carried out cancer hotspot panel sequencing to detect secondary resistance-conferring mutations in KIT. Furthermore, as a step towards clinical exploitation of the recently described signatures of mutational processes in cancer genomes, we established and applied a novel bioinformatics algorithm that enables supervised analysis of the mutational catalogs of individual tumors.Molecularly guided treatment with imatinib in analogy to the management of gastrointestinal stromal tumor (GIST) resulted in a dramatic and durable response with remission of nearly all tumor manifestations, indicating a dominant driver function of mutant KIT in this tumor. KIT dependency was further validated by a secondary KIT exon 17 mutation (c.2459_2462delATTCinsG, p.D820_S821delinsG) that was detected upon tumor progression after 10 months of imatinib treatment and provided a rationale for salvage therapy with regorafenib, which has activity against KIT exon 11/17 mutant GIST.These observations highlight the potential of unbiased genomic profiling for uncovering the vulnerabilities of individual malignancies, particularly in rare and unclassifiable tumors, and underscore that KIT exon 11 mutations represent tractable therapeutic targets across different histologies.

Ferromanganese [Fe/Mn] crusts formed on basaltic seamounts, gain considerable economic importance due to their high content of Co, Ni, Cu, Zn and Pt. The deposits are predominantly found in the Pacific Ocean in depths of over 1000 m. They are formed in the mixing layer between the upper oxygen-minimum zone and the lower oxygen-rich bottom zone. At present an almost exclusive abiogenic origin of crust formation is considered. We present evidence that the upper layers of the crusts from the Magellan Seamount cluster are very rich in coccoliths/coccolithophores (calcareous phytoplankton) belonging to different taxa. Rarely intact skeletons of these unicellular algae are found, while most of them are disintegrated into their composing prisms or crystals. Studies on the chemical composition of crust samples by high resolution SEM combined with an electron probe microanalyzer (EPMA) revealed that they are built of distinct stacked piles of individual compartments. In the center of such piles Mn is the dominant element, while the rims of the piles are rich in Fe ( mineralization aspect). The compartments contain coccospheres usually at the basal part. Energy dispersive X-ray spectroscopy (EDX) analyses showed that those coccospheres contain, as expected, CaCO3 but also Mn-oxide. Detailed analysis displayed on the surface of the coccolithophores a high level of CaCO3 while the concentration of Mn-oxide is relatively small. With increasing distance from the coccolithophores the concentration of Mn-oxide increases on the expense of residual CaCO3. We conclude that coccoliths/coccolithophores are crucial for the seed/nucleation phase of crust formation ( biomineralization aspect). Subsequently, after the biologically induced mineralization phase Mn-oxide deposition proceeds “auto”catalytically.

Mineralization of calcium carbonate in aqueous solutions starting from its initiation was studied by time-resolved small-angle neutron scattering (SANS). SANS revealed that homogeneous crystallization of CaCO 3 involves an initial formation of thin plate-shaped nuclei which subsequently reassemble to 3-dimensional particles, first of fractal and finally of compact structure. The presence of the egg-white protein ovalbumin leads to a different progression of mineralization through several stages; the first step represents amorphous CaCO 3, whereas the other phases are crystalline. The formation and dissolution of the amorphous phase is accompanied by Ca (2+)-mediated unfolding and cross-linking of about 50 protein monomers showing the characteristic scattering of linear chains with a large statistical segment length. The protein complexes act as nucleation centers for the amorphous phase because of their enrichment by Ca (2+) ions. SANS revealed the sequential formation of CaCO 3 starting from the amorphous phase and the subsequent formation of the crystalline polymorphs vaterite and aragonite. This formation from less dense to more dense polymorphs follows the Ostwald-Volmer rule.

Bioencapsulation is an intriguing way to immobilize biological materials, including cells, in silica, metal-oxides or hybrid sol-gel polymers. Until now only the sol-gel precursor technology was utilized to immobilize bacteria or yeast cells in silica. With the discovery of silicatein, an enzyme from demosponges that catalyzes the formation of poly(silicate), it became possible to synthesize poly(silicate) under physiological (ambient) conditions. Here we show that Escherichia coli can be transformed with the silicatein gene, its expression level in the presence of isopropyl beta-D-thiogalactopyranoside (IPTG) can be efficiently intensified by co-incubation with silicic acid. This effect could be demonstrated on the level of recombinant protein synthesis as well as by immunostaining analysis. The heterologously produced silicatein is enzymatically active, as confirmed by staining with Rhodamine 123 (formation for poly[silicate] from silicic acid) and by reacting free silicic acid with the beta-silicomolybdato color system. Electron microscopic analysis revealed that the bacteria that express silicatein form a viscous cover around them when growing in the presence of silicic acid. Finally, we demonstrate that the growth kinetics of E. coli remains unaffected whether or not the bacteria had been transformed with silicatein or grown in medium, supplemented with silicic acid. It is concluded that silicatein-mediated encapsulation of bacteria with silica might improve, extend and optimize the range of application of bacteria for the production of recombinant protein.

A distinct nanogranular fine structure is shared by a wealth of biominerals from several species, classes and taxa. This nanoscopic organization affects the properties and behavior of the biogenic ceramic material and confers on them attributes that are essential to their function. We present a set of structure-relationship properties that are rooted in the nanogranular organization and we propose that they rest on a common pathway of formation, a colloid-driven and hence nonclassical mode of crystallization. With this common modus operandi, we reveal the most fundamental and wide spread process-structure-property relationship in biominerals. With the recent increase in our understanding of nonclassical crystallization in vitro and in vivo, this significant process-structure-property relationship will serve as a source for new design approaches of bio-inspired materials.

Recent research has shown that biominerals and their biomimetics (i) typically form via an amorphous precursor phase, and (ii) commonly display a nanogranular texture. Apparently, these two key features are closely related, underlining the fact that the formation of biominerals and their biomimetics does not necessarily follow classical crystallization routes, and leaves a characteristic nanotextural imprint which may help to disclose their origins and formation mechanisms. Here we present a general overview of the current theories and models of nonclassical crystallization and their applicability for the advance of our current understanding of biomineralization and biomimetic mineralization. We pay particular attention to the link between nonclassical crystallization routes and the resulting nanogranular textures of biomimetic CaCO3 mineral structures. After a general introductory section, we present an overview of classical nucleation and crystal growth theories and their limitations. Then, we introduce the Ostwald's step rule as a general framework to explain nonclassical crystallization. Subsequently, we describe nonclassical crystallization routes involving stable prenucleation clusters, dense liquid and solid amorphous precursor phases, as well as current nonclassical crystal growth models. The latter include oriented attachment, mesocrystallization and the new model based on the colloidal growth of crystals via attachment of amorphous nanoparticles. Biomimetic examples of nanostructured CaCO3 minerals formed via these nonclassical routes are presented which help us to show that colloid-mediated crystal growth can be regarded as a wide-spread growth mechanism. Implications of these observations for the advance in the current understanding on the formation of biomimetic materials and biominerals are finally outlined.

Siliceous sponges can synthesize poly(silicate) for their spicules enzymatically using silicatein. We found that silicatein exists in silica-filled cell organelles (silicasomes) that transport the enzyme to the spicules. We show for the first time that recombinant silicatein acts as a silica polymerase and also as a silica esterase. The enzymatic polymerization/polycondensation of silicic acid follows a distinct course. In addition, we show that silicatein cleaves the ester-like bond in bis(p-aminophenoxy)-dimethylsilane. Enzymatic parameters for silica esterase activity are given. The reaction is completely blocked by sodium hexafluorosilicate and E-64. We consider that the dual function of silicatein (silica polymerase and silica esterase) will be useful for the rational synthesis of structured new silica biomaterials.