BugLab LLC, the industry leader in non-invasive optical monitoring, has been granted US Patent 8,405,033, with claims encompassing many aspects of BugLab's optical biomass measuring devices.
The patent includes methods for non-invasively measuring biomass through the side wall of a shake flask, utilizing a handheld sensor (e.g. BugLab's "OD Scanner"). This eliminates the time, labor, contamination risk, and inaccuracy associated with sampling and dilutions.
A key component of the invention is the measurement of particle back-scatter using light at wavelengths that travel only a limited distance into culture media. This allows the scientist to make accurate measurements in small fluid volumes, such as are often encountered in shake flasks. Other aspects of the invention include methods for reducing sensitivity to vessel thickness and material type. In practice, BugLab's OD Scanner device is able to make accurate measurements on vessels constructed from both glass and plastic (e.g. PC, PET) materials, with sizes ranging from 250 to 2000 mL.
Methods for preventing or rejecting inaccurate readings are also provided in the patent. Position sensors are used in the OD Scanner to detect the vessel position and automatically initiate a measurement when sufficient contact is achieved. Redundant optical detectors are used to reject measurements made when insufficient fluid is present in front of the measurement window. In practice, the OD Scanner is simply positioned against a flask and the biomass result is reported within seconds.
Calibration of the device to specific organisms is also described in the patent. The OD Scanner has been tested and shown effective in measuring several microorganisms and cultures including E. coli, yeast, and algae and can be custom-calibrated for most organisms studied in labs today. This novel device will provide benefit in many areas of application including biopharmaceutical research and production, academic and industrial microbiology, industrial brewing, and biofuels research.