Mapping nanomechanical properties of freshly grown, native, interlamellar organic sheets on flat pearl nacre

Launspach, Malte; Gries, Katharina; Heinemann, Fabian; Hübner, Anja; Fritz, Monika; Radmacher, Manfred

doi:10.1016/j.actbio.2014.02.050

Cited by 10 publications

(7 citation statements)

References 30 publications

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“…Here we used a Poisson ratio of v ¼ 0.5 and a half-opening angle of a ¼ 18˚, as given by the manufacturer. The spring constants was 1.27 N/m, which was determined with the thermal noise method (Launspach et al, 2014).…”

Section: Biophysical and Nanomechanical Analysismentioning

confidence: 99%

Detection of CD28/CD86 co‐stimulatory molecules and surface properties of T and dendritic cells: An AFM study

et al. 2015

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Although the importance of B7/CD28 co-stimulation has been widely studied, little is known about their nano-spatial localization and their corresponding cells' biophysical and biomechanical properties. Here, we investigated the morphological, biophysical, and biomechanical properties of T cells and dendritic cells (DCs) by atomic force microscopy (AFM) and force curves. The nano-spatial distribution of CD28 and CD86 antigen on T cells and DCs was detected by CD86 or CD28 antibody-functionalized AFM tip. Single-molecule force spectroscopy (SMFS)-based force volumes and quantum dots (QDs)-based fluorescence imaging demonstrated that the co-stimulatory molecules were not randomly distributed over the cells' surface, but more than 80% of CD28 and CD86 molecules appeared to be expressed as 100-200 nm nanoclusters and polarize dominantly in the peak of the cell membrane fluctuations. AFM imaging and quantitative analysis showed that the roughness of mature DCs (mDCs) was higher than that of immature DCs (iDCs). The adhesion force distribution of iDCs and mDCs was heterogeneous while the elasticity distribution was homogeneous locally. In addition, mDCs had a fourfold increase of Young's modulus of iDCs, indicating the contribution of the actin cytoskeleton to the elastic properties of the cells. Taken together, the nano-cluster distribution of CD28 and CD86, the rough mDCs surface, the higher adhesion force and elasticity of mDCs may facilitate to the occurrence of B7/CD28 co-stimulation signals and the formation of immune synapse. These nanoscale findings provide new insights into the antigen-presenting function of DCs, the T cell activation and ultimate immune response. SCANNING 38:365-375, 2016. © 2015 Wiley Periodicals, Inc.

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Section: Biophysical and Nanomechanical Analysismentioning

confidence: 99%

Detection of CD28/CD86 co‐stimulatory molecules and surface properties of T and dendritic cells: An AFM study

et al. 2015

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“…The widespread phenomenon of biomineralization is an elaborately controlled process by which living organisms form minerals, leading to a variety of biological structures such as teeth, bone, otoliths, spicules, shell and pearl . The shell and pearl of mollusks have been extensively studied because of their notable mechanical properties and medicinal value . The pearl oyster, Pinctada fucata , which has the unique ability to produce pearls, is one of the most studied models to investigate the mechanism of biomineralization.…”

Section: Introductionmentioning

confidence: 99%

The transcription factor Pf‐POU3F4 regulates expression of the matrix protein genes Aspein and Prismalin‐14 in pearl oyster (Pinctada fucata)

et al. 2016

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Matrix proteins play key roles in shell formation in the pearl oyster, but little is known about how these proteins are regulated. Here, two POU domain family members, Pf‐POU2F1 and Pf‐POU3F4, were cloned and characterized. Functional domain analysis revealed that both them have conserved POUS and POUH domains; these domains are important for transcription factor function. The tissue distributions of Pf‐POU2F1 and Pf‐POU3F4 mRNAs in pearl oyster revealed different expression patterns, and the expression of Pf‐POU3F4 mRNA was relatively high in the mantle. The promoters of the matrix protein genes Aspein and Prismalin‐14 were cloned using genome‐walking PCR. Relatively high transcriptional activities of these promoters were detected in HEK‐293T cells. In transient co‐transfection assays, Pf‐POU3F4 greatly up‐regulated the promoter activities of the Aspein and Prismalin‐14 genes in a dose‐dependent manner. Structural integrity of Pf‐POU3F4 was essential for its activation function. One region of the Aspein gene promoter, −181 to −77 bp, and two binding sites in the Prismalin‐14 gene promoter, −359 to −337 bp and −100 to −73 bp, were required for activation of Pf‐POU3F4. An electrophoresis mobility shift assay demonstrated that Pf‐POU3F4 directly bound these sites. Pf‐POU3F4 knockdown led to a decrease in Aspein and Prismalin‐14 gene expression. Furthermore, expression levels for the Pf‐POU3F4 gene were similar to those of the Aspein and Prismalin‐14 genes during five development stages. Taken together, these results suggest that the transcription factor Pf‐POU3F4 regulates expression of the matrix protein genes Aspein and Prismalin‐14 in pearl oyster. Database The nucleotide sequence data of Pf‐POU2F1 is available in the GenBank databases under the accession number http://www.ncbi.nlm.nih.gov/protein/KM588196. The nucleotide sequence data of Pf‐POU3F4 is available in the GenBank databases under the accession number http://www.ncbi.nlm.nih.gov/protein/KM519606. The nucleotide sequence data of Aspein gene promoter is available in the GenBank databases under the accession number http://www.ncbi.nlm.nih.gov/protein/KM519607. The nucleotide sequence data of Prismalin‐14 gene promoter is available in the GenBank databases under the accession number http://www.ncbi.nlm.nih.gov/protein/KM519601.

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“…Ceramics have been widely used in certain harsh service environments, since they possess low density, high strength, high temperature stability, and excellent oxidation and corrosion resistances. − However, the low tolerance to damage greatly limits the scope of their applications as structural engineering materials. , In contrast, innumerable biological ceramic materials with outstanding damage-resistance are used for structural purposes in nature. − The most representative example is probably the mollusk shell, which consists of more than 90 wt % of calcium carbonate (CaCO 3 ) and a small amount of organic matrix . Owing to the combination of building blocks over multiple length scales in a complex hierarchical architecture, they exhibit excellent strength and toughness, far exceeding those of their individual constituents. , As such, mollusk shells have been extensively studied, and considered as an inspiration source of artificial structural materials. − …”

Section: Introductionmentioning

confidence: 99%

An Ingenious Microstructure Arrangement in Deep-Sea Nautilus Shell against the Harsh Environment

Liang

et al. 2021

ACS Biomater. Sci. Eng.

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Mollusk shells generally consist of several macrolayers with different microstructures. To explore the specific role that different macro-layers play in the overall mechanical properties of shells, the microstructures, hardness distribution, and three-point bending behavior in the deep-sea Nautilus shell were investigated. It is found that the shell presents a hierarchical structure comprising three layers in thickness, that is, the outer, middle, and inner layers, which exhibit homogeneous, prismatic, and nacreous structures, respectively. Among them, the homogeneous structure in the outer layer is harder, which is beneficial for the shell to enhance resistance to wear and perforation. Furthermore, both the bending strength and fracture energy for group Up (loading from outer to inner surfaces) are far higher than those for group Down (loading from inner to outer surfaces), indicating that the inner nacreous layer is not only stronger but also tougher. Cracks tend to deflect at the interfaces in nacreous structure, and nacreous structure is thereby more resistant to breakage. Hence, the nacreous structure in the inner layer could protect the shell from breaking catastrophically in the deep sea with high pressure. In brief, the combination of a harder outside layer and a tougher inside layer provides an effective protective structure for the deep-sea shell, and the excellent environment adaptability of Nautilus shell can thus be interpreted in terms of its ingenious microstructure arrangement.

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Mapping nanomechanical properties of freshly grown, native, interlamellar organic sheets on flat pearl nacre

Cited by 10 publications

References 30 publications

Detection of CD28/CD86 co‐stimulatory molecules and surface properties of T and dendritic cells: An AFM study

Detection of CD28/CD86 co‐stimulatory molecules and surface properties of T and dendritic cells: An AFM study

The transcription factor Pf‐POU3F4 regulates expression of the matrix protein genes Aspein and Prismalin‐14 in pearl oyster (Pinctada fucata)

An Ingenious Microstructure Arrangement in Deep-Sea Nautilus Shell against the Harsh Environment

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