Genotype of CHO host cell line has higher impact on mAb production and quality than process strategy or cell culture medium

Chinese hamster ovary (CHO) cells comprise a variety of lineages, including CHO-DXB11, CHO-K1, CHO-DG44 and CHO-S. Despite the fact that CHO cell lines share a common ancestor, extensive mutagenesis and clonal selection have resulted in substantial genetic heterogeneity among them. Data from sequencing shows that different genes are lacking from individual CHO cell lines and that each cell line harbors a unique set of mutations that are relevant to the bioprocess. However, literature outlining how the observed genetic differences affect CHO cell performance during bioprocess operations remains scarce. In this study, we examined host cell-specific differences among three widely used CHO cell lines (CHO-K1, CHO-S and CHO-DG44) and recombinantly expressed the same monoclonal antibody (mAb) in an isogenic format in all cell lines by using bacterial artificial chromosomes (BACs) as transfer vector. Cell-specific growth, product formation and heavy and light chain mRNA levels were studied in batch, fed-batch and perfusion cultures. Furthermore, two different cell culture media were investigated. Product quality was studied through glycoprofiling, and the thermal denaturation was analyzed using differential scanning calorimetry (DSC). We found CHO cell line-specific preferences for mAb production or biomass synthesis that were determined by the host cell line rather than product-specific mRNA levels. Additionally, quality attributes of the expressed mAb were influenced by the host cell line and medium used

A new member of a class of rod-like Mn12_{12} single molecule magnets using 2-(pyridine-2-ly)propan-2-ol

This paper reports on the synthesis, structure and magnetic properties of a new type of rod like Mn₁₂ metal cluster, [Mn₁₂O₇(OH)₂(OMe)₂(dmhmp)₄(O₂CPh)₁₁(H₂O)] (6) where the ligand (dmhmpH) is 2-(pyridine-2-yl) propan-2-ol. Compound (6) was obtained by reacting MnCl₂•4H₂O with dmhmpH in the presence of benzoic salt and Et₃N. The resulting crystalline material is assigned to the triclinic space group P1̄. Although compound (6) displays ferromagnetic and antiferromagnetic competition behavior, this does not prevent the molecule from functioning as a single-molecule magnet (SMM). The SMM behavior is evidenced by observing frequency dependent out-of-phase ac signals as well as magnetization hysteresis loops at low temperatures in a micro-SQUID study. A brief comparison between all rod-like Mn₁₂ materials is also given in the manuscript

Control of polarization in bulk ferroelectrics by mechanical dislocation imprint

Defects are essential to engineering the properties of functional materials ranging from semiconductors and superconductors to ferroics. Whereas point defects have been widely exploited, dislocations are commonly viewed as problematic for functional materials and not as a microstructural tool. We developed a method for mechanically imprinting dislocation networks that favorably skew the domain structure in bulk ferroelectrics and thereby tame the large switching polarization and make it available for functional harvesting. The resulting microstructure yields a strong mechanical restoring force to revert electric field–induced domain wall displacement on the macroscopic level and high pinning force on the local level. This induces a giant increase of the dielectric and electromechanical response at intermediate electric fields in barium titanate [electric field–dependent permittivity (ε33) ≈ 5800 and large-signal piezoelectric coefficient (d33*) ≈ 1890 picometers/volt]. Dislocation-based anisotropy delivers a different suite of tools with which to tailor functional materials.</p

Control of polarization in bulk ferroelectrics by mechanical dislocation imprint

Defects are essential to engineering the properties of functional materials ranging from semiconductors and superconductors to ferroics. Whereas point defects have been widely exploited, dislocations are commonly viewed as problematic for functional materials and not as a microstructural tool. We developed a method for mechanically imprinting dislocation networks that favorably skew the domain structure in bulk ferroelectrics and thereby tame the large switching polarization and make it available for functional harvesting. The resulting microstructure yields a strong mechanical restoring force to revert electric field–induced domain wall displacement on the macroscopic level and high pinning force on the local level. This induces a giant increase of the dielectric and electromechanical response at intermediate electric fields in barium titanate [electric field–dependent permittivity (ε33) ≈ 5800 and large-signal piezoelectric coefficient (d33*) ≈ 1890 picometers/volt]. Dislocation-based anisotropy delivers a different suite of tools with which to tailor functional materials.This is the author’s version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science on May 28, 2021 (vol. 372). DOI: 10.1126/science.abe3810.</p

Control of polarization in bulk ferroelectrics by mechanical dislocation imprint

Defects are essential to engineering the properties of functional materials ranging from semiconductors and superconductors to ferroics. Whereas point defects have been widely exploited, dislocations are commonly viewed as problematic for functional materials and not as a microstructural tool. We developed a method for mechanically imprinting dislocation networks that favorably skew the domain structure in bulk ferroelectrics and thereby tame the large switching polarization and make it available for functional harvesting. The resulting microstructure yields a strong mechanical restoring force to revert electric field–induced domain wall displacement on the macroscopic level and high pinning force on the local level. This induces a giant increase of the dielectric and electromechanical response at intermediate electric fields in barium titanate [electric field–dependent permittivity (ε33) ≈ 5800 and large-signal piezoelectric coefficient (d33*) ≈ 1890 picometers/volt]. Dislocation-based anisotropy delivers a different suite of tools with which to tailor functional materials.This is the author’s version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science on May 28, 2021 (vol. 372). DOI: 10.1126/science.abe3810.</p