The globally published data on recycled aggregate standards (normative documents) of various countries have been systematically analysed and evaluated, and some barriers mentioned.
Since the aggregates induced by NaCl and FT were unstable, all aggregate standards were prepared freshly for further experiments.
In order to ensure stability of the aggregate standards, mAb1 and mAb2 were stressed and analyzed after storage at RT.
This study highlights that aggregate quantification directly in the cell culture supernatant using appropriate SEC columns with suitable mAb aggregate standards is feasible without falsification by previous affinity chromatography.
Since 500 mmol L−1 NaCl induced a significant amount of small aggregates (3.0% dimer) without forming large HMW species of mAb2, this concentration was used to induce mAb2 dimers for stability studies and the generation of aggregate standards.
Since FT induced more aggregates than the other stress methods, this technique was chosen in addition to NaCl-induction for further stability studies and the generation of aggregate standards.
In order to distinguish between different HMW species formed in cell culture, mAb dimers, tetramers, oligomers and large aggregates with diameter above 100 nm were induced using different stress techniques to be used as aggregate standards.
Our results demonstrate that SE-HPLC analysis using a high-resolution column in combination with suitable aggregate standards can be a valuable tool to determine aggregate formation in cell culture, as the method allows quantification of mAb aggregate content within 20 min directly in the cell culture supernatant without falsifying the results by labor-intensive pre-purification of the samples.
Since both antibodies formed large aggregates and mAb2 was also degraded to fragments, pH-shift was not used for further stability studies and for the generation of aggregate standards.> Increased salt concentration reduces the colloidal stability by suppressing electrostatic repulsion, leading to aggregation [ 25].
In this metamaterial, which we call metaconcrete, the stone, sand, and gravel aggregates of standard concrete are replaced with spherical inclusions consisting of a heavy metal core coated with a soft outer layer.
Indeed, more than 90% of the log phase population appeared to grow as aggregates under standard laboratory conditions (Figure 1BC, 6A).
