Truly continuous low pH viral inactivation for biopharmaceutical process integration

Continuous virus inactivation (VI) has received little attention in the efforts to realize fully continuous biomanufacturing in the future. Implementation of continuous VI must assure a specific minimum incubation time, typically 60 min. To guarantee the minimum incubation time, we implemented a packed bed continuous viral inactivation reactor (CVIR) with narrow residence time distribution (RTD) for low pH incubation. We show that the RTD does not broaden significantly over a wide range of linear flow velocities-which highlights the flexibility and robustness of the design. Prolonged exposure to acidic pH has no impact on bed stability, assuring constant RTD throughout long term operation. The suitability of the packed bed CVIR for low pH inactivation is shown with two industry-standard model viruses, that is xenotropic murine leukemia virus and pseudorabies virus. Controls at neutral pH showed no system-induced VI. At low pH, significant VI is observed, even after only 15 min. Based on the low pH inactivation kinetics, the continuous process is equivalent to traditional batch operation. This study establishes a concept for continuous low pH inactivation and, together with previous reports, highlights the versatility of the packed bed reactor for continuous VI, regardless of the inactivation method.

Long-Term, High-Spatiotemporal Resolution Recording From Cultured Organotypic Slices with High-Density Microelectrode Arrays

A novel system to cultivate and record brain slices directly on high-density microelectrode arrays (HD-MEA) was developed. This system allows to continuously record electrical activity of selected individual neurons at high spatial resolution, while monitoring neuronal network activity at the same time. For the first time, properties of single neurons and the corresponding neuronal network in an organotypic hippocampal slice culture were studied over four consecutive weeks at daily intervals.

226Ra in drinking water in the Republic of Croatia

Owing to its exceptional radiotoxicity 226Ra in drinking water may directly affect human health. Its presence was investigated in several categories of drinking water in Croatia: well water, tap water from several municipal water supply systems and bottled mineral water. The method of 226Ra determination was alpha-spectrometric measurement after radiochemical separation. The 226Ra content in all investigated categories of waters are below the legislative level permissible for human health.