Label-free independent quantitation of viable and non-viable cells using a multivariable multi-resonant sensor.

Biological cells are utilized for diverse biotechnological and bioengineering purposes ranging from the production of biopharmaceuticals, to cell therapy, "human-on-a-chip" drug and toxicology assays, and drug-resistance tests. In these and other applications, it is critical to quantify the levels of not only viable but also non-viable cells. While traditional off-line cell-staining methods are available for counting of non-viable cells, many applications cannot periodically remove cells for their off-line analysis because of the risk of contamination or workflow logistics. Here we show in-situ label-free quantitation of viable and non-viable cells with multivariable multi-resonant sensors. We used Chinese hamster ovary (CHO) cells in suspension culture in single-use bioreactors as a representative example. The resonant sensor design strategy permitted enhanced sensor sensitivity versus conventional non-resonant measurements and probed the spectral dispersion of viable and non-viable cells with multiple resonances. These capabilities of label-free in-situ analysis of cell viability can be attractive in diverse cell applications such as cell suspensions, adhered cells, and their 3D assemblages.

Passive multivariable temperature and conductivity RFID sensors for single-use biopharmaceutical manufacturing components.

Single-use biopharmaceutical manufacturing requires monitoring of critical manufacturing parameters. We have developed an approach for passive radio-frequency identification (RFID)-based sensing that converts ubiquitous passive 13.56 MHz RFID tags into inductively coupled sensors. We combine several measured parameters from the resonant sensor antenna with multivariate data analysis and deliver unique capability of multiparameter sensing and rejection of environmental interferences with a single sensor. We demonstrate here the integration of these RFID sensors into single-use biopharmaceutical manufacturing components. We have tested these sensors for over 500 h for measurements of temperature and solution conductivity with the accuracy of 0.1°C (32-48°C range) and accuracy of 0.3-2.9 mS/cm (0.5-230 mS/cm range). We further demonstrate simultaneous temperature and conductivity measurements with an individual RFID sensor with the accuracy of 0.2°C (5-60°C range) and accuracy of 0.9 mS/cm (0.5-183 mS/cm range). Developed RFID sensors provide several important features previously unavailable from other single-use sensing technologies such as the same sensor platform for measurements of physical, chemical, and biological parameters; multi-parameter monitoring with individual sensors; and simultaneous digital identification.