The Rabit: A Rapid Automated Biodosimetry Tool for Radiological Triage

Abstract

In response to the recognized need for high throughput biodosimetry methods for use after large scale radiological events, a logical approach is complete automation of standard biodosimetric assays that are currently performed manually. We describe progress to date on the RABIT (Rapid Automated BIodosimetry Tool), designed to score micronuclei or γ-H2AX fluorescence in lymphocytes derived from a single drop of blood from a fingerstick. The RABIT system is designed to be completely automated, from the input of the capillary blood sample into the machine, to the output of a dose estimate. Improvements in throughput are achieved through use of a single drop of blood, optimization of the biological protocols for in-situ analysis in multi-well plates, implementation of robotic plate and liquid handling, and new developments in high-speed imaging. Automating well-established bioassays represents a promising approach to highthroughput radiation biodosimetry, both because high throughputs can be achieved, but also because the time to deployment is potentially much shorter than for a new biological assay. Here we describe the development of each of the individual modules of the RABIT system, and show preliminary data from key modules. Ongoing is system integration, followed by calibration and validation.

THE DECADE OF THE RABiT (2005–15)

“…RABiT development was divided into two phases with a simpler phase 1 system initially developed for lower throughput (~6000 samples per day) (3) and a phase 2 system with improved performance and throughput reaching 30 000 samples per day (4) . Due to the extended nature of the assays, and the parallelized nature of sample handling in the RABiT, we define throughput as the number of samples entering/exiting the system at steady state.…”

“…In phase 2, the harvest station was parallelized (4) to process four capillaries at once, using dedicated robotics, with a 5-fold reduction in the processing time of 2.2 s per capillary (8.8 s for four capillaries), freeing up the SCARA robot for other tasks. An additional change required for the RABiT to achieve high throughput was to increase the incubator capacity, allowing storage of more samples during the culturing step of the micronucleus assay and this could not be accomplished due to financial constraints.…”

“…To fulfill this need, the Columbia Center for High Throughput Minimally Invasive Radiation Biodosimetry, funded by NIAID (National Institute of Allergy and Infectious Diseases), began the development of the Rapid Automated Biodosimetry Tool (RABiT), as an end-to-end automated, ultrahigh throughput robotically-based biodosimetry workstation (2)(3)(4)(5)(6)(7) . Although different procedural steps involved in cytogenetic bioassays (from chromosome preparations (8) , to scoring (9) and sample tracking (10) ) had previously been automated, the RABiT is presumably the first end-to-end system developed thus far where the only human intervention with samples is at the sample collection step (11) and interpretation of the reported results by a qualified medical professional.…”

Advances in Mitigation of Injuries from Radiological Terrorism or Nuclear Accidents

“…The EPR signal is durable and it appears that the techniques can detect doses as low as 2 Gy 36,39,40 . Dr David Brenners group at Columbia University Medical Centre (New York, USA) has taken a very different approach, and is developing an automated device for measuring radiation-induced micronuclei and d-H2AX fluorescence in blood lymphocytes 41 . However, machines such as these will not be deployed anytime soon, as currently there is no market to support the cost of manufacturing the units and/or the cost of getting these approved by the required authorities (e.g., in the USA, by the Food and Drug Administration).…”

Liquid Handling Optimization in High-Throughput Biodosimetry Tool

“…Due to the need of high-speed and efficient of biodosimetric assays for triage and therapy, a RABiT has been developed by the Center for High-Throughput Minimally Invasive Radiation Biodosimetry at Columbia University over the past few years [3][4][5].…”