Extended lnfectivity Assay - Amplification and Detection of Retroviral Contaminations in a Lab-on-a-Chip

retroviral vectors are the most commonly used gene-delivery system in biomedical research due to their stabile integration into the host As genome and inheritance during cell replication. Despite the recently achieved safety improvements using replicaton-defective retroviral vectors still pose a hazard potential of obtaining replication-competent viruses due to recombination events during vector preparation. Consequently, stringent governmental regulations mandate extensive screening for replication-competent retroviruses in all products, vectors and transduced cell lines. Among others cell-based infectivity assays are routinely performed to determine the presence of viral infections or to demonstrate viral clearance. Although cell-based assays are widely used they suffer from poor reproducibility, reliability and are time and labor-intensive. To overcome these technological limitations we have developed a miniaturized and automated a cell-based microsystem consisting of embedded impedance microsensors enabling non-invasive monitoring of virus infections in cell cultures. Our extended infectivity assay is based an simultaneous cellular virus amplification und cellular virus recognition by combining two microfluidic cell cultures an a single chip platform. While virus amplification and release is accomplished by M.dunni resulting viral infection is detected the indicator cell line PG-4. We demonstrated that the integration of two cell cultures in a lab-on-a-chip containing embedded microsensors allows for reliable identification of retrovirus activity within 70 hours using Murine Leukemia Virus based assay.