Priming cells for their final destination: microenvironment controlled cell culture by a modular ECM-mimicking feeder film.

Mammalian cell culture is the starting point in many research studies focusing on biomedical applications. However, researchers have little control over the standardized cell microenvironment parameters. Here a modular ECM-mimicking surface coating for cell culture environment is designed. This substrate is a new and versatile thin film obtained by spin-coating of concentrated gelatin crosslinked by transglutaminase. It can be modified with respect to the biochemical and biophysical needs of the final cell destination, i.e. it delivers loaded multi-growth factors and serum components and allows for cell culture in a serum-free culture medium. Also, a well-known cell behavior modulator, the substrate stiffness, is controlled exogenously by addition of nanoparticles. In addition to growth factors, antimicrobial agents such as natural peptides are added to the substrate for limiting the repeated addition of antimicrobial agents to the culture medium and to prevent the increase of resistant bacterial strains in the culture environment. Finally, this substrate contains simultaneously ECM components, growth factors, stiffening elements and antimicrobial agents. It provides a favorable microenvironment and sterile conditions. It is a free-of-maintenance system, as cells will grow without addition of serum or antimicrobial cocktails. This low cost and easy-to-use substrate could emerge as a new standard for cell culture.

Monoclonal antibodies biosimilarity assessment using transient isotachophoresis capillary zone electrophoresis-tandem mass spectrometry.

Out of all categories, monoclonal antibody (mAb) therapeutics attract the most interest due to their strong therapeutic potency and specificity. Six of the 10 top-selling drugs are antibody-based therapeutics that will lose patent protection soon. The European Medicines Agency has pioneered the regulatory framework for approval of biosimilar products and approved the first biosimilar antibodies by the end of 2013. As highly complex glycoproteins with a wide range of micro-variants, mAbs require extensive characterization through multiple analytical methods for structure assessment rendering manufacturing control and biosimilarity studies particularly product and time-consuming. Here, capillary zone electrophoresis coupled to mass spectrometry by a sheathless interface (CESI-MS) was used to characterize marketed reference mAbs and their respective biosimilar candidate simultaneously over different facets of their primary structure. CESI-MS/MS data were compared between approved mAbs and their biosimilar candidates to prove/disconfirm biosimilarity regarding recent regulation directives. Using only a single sample injection of 200 fmol, CESI-MS/MS data enabled 100% amino acids (AA) sequence characterization, which allows a difference of even one AA between 2 samples to be distinguished precisely. Simultaneously glycoforms were characterized regarding their structures and position through fragmentation spectra and glycoforms semiquantitative analysis was established, showing the capacity of the developed methodology to detect up to 16 different glycans. Other posttranslational modifications hotspots were characterized while their relative occurrence levels were estimated and compared to biosimilars. These results proved the value of using CESI-MS because the separation selectivity and ionization efficiency provided by the system allowed substantial improvement in the characterization workflow robustness and accuracy. Biosimilarity assessment could be performed routinely with a single injection of each candidate enabling improvements in the biosimilar development pipeline.