High Throughput Microrepository for Genetic Materials Recognizing the urgent need for a safe, rapid and reliable means of preserving and archiving genetic samples and other biological materials, such as synthetic DNA samples, unique isolated samples, plasmids, forensic samples, patient samples, samples to ensure future biodiversity in plants or animals, clones and archeological samples, a study panel recently convened by NIH NCRR identified the areas of most critical need and made several recommendations. The 1st and 5th items on their list of major recommendations were to "encourage the development of high throughput and scalable technologies for Germplasm processing and cryopreservation" and "support novel 'high risk/high return'preservation technologies that will break new ground". We have directly and successfully addressed these needs with our Microrepository for Genetic Materials (MGM) technology which affords completely scalable, very high density sample storage with automated retrieval from arrays of optically multiplexed encoded beads by providing sample preparation-identification-archiving-retrieval functions on a single platform. For the Phase I effort, a completely automated prototype MGM platform was successfully built and tested. The MGM contains dense arrays of porous glass or polymer beads, groups of smaller beads or paper swatches, each of which contains a different DNA sample, which have been optically encoded with our rare earth-based Parallume technology which allows each bead to be optically identified uniquely. After placement of the DNA onto either single large beads, the beads are loaded into Bead Localization Slides (BLS), which optically isolate the beads into a planar monolayer for imaging, and the optical code of each bead is read to determine the location of that particular DNA sample. The beads are retrieved and placed in the desired location and the lack of contamination during handling confirmed by qPCR. By performing additional experiments, including incorporation of new improved hardware designs and successfully changing the chemical composition of the Parallume encoding materials to prevent UV damage to the DNA, we have addressed all Reviewers'concerns. We have now built and successfully tested a completely functional prototype MGM instrument and, in response to the insightful Reviewers'comments, we have modified the Parallume materials so as to allow excitation with a longer wavelength of excitation light (365nm) which (a) prevents the photochemical decomposition of the DNA during optically decoding the samples, (b) allows non-UV optics to be used to focus the light and (c) lets much brighter, longer lived and less expensive LED light sources be used. A new surface chemistry, which strongly binds the DNA to the bead until it is chemically released, will provide yet another level of sample contamination protection. The improved MGM described here represents the first substantial progress since inception of the field in addressing the rapidly expanding storage requirements for DNA and nucleic acids. A new storage paradigm which employs optically encoded bead technology provides a sample density, degree of automation and simplicity not currently possible and with scalability to successfully store and retrieve any number of DNA samples for the foreseeable future.
In recent years there has been a very large increase in the number of samples of genetic materials such as DNA that have been synthesized or isolated from organisms. Some of these samples, such as an individual's DNA, forensic samples or genetic material from a new strain of bacteria are one-of-a-kind and cannot be replaced. However, there is currently no means to organize or automatically archive and retrieve DNA samples in an automatic and high throughput manner. Because of the increase in throughput from laboratories, governments, hospitals and universities, the problem is only expected to grow in the future. We offer here a design of a new instrument platform designated as the Microrepository for Genetic Materials (MGM). The samples will be stored in arrays of porous glass beads with each of the beads displaying an optical code or signature that uniquely identifies that particular sample and the DNA within that bead. The DNA samples are each placed into a single highly porous bead with a diameter of 50 microns (0.05mm). The beads are optically encoded with our ParallumeTM technology which allows each bead to be identified by the intensity ratios of the different colors emitted by the bead upon excitation. Thus, thousands of beads can be mixed together, each identified by its unique optical code and removed from the storage array using an optical fiber to pick it up. After checking the optical signature by examining the emitted light when the bead is picked up by the optical fiber, the bead can be placed in the desired destination location. Thus, we are able to design and build a repository that can store hundreds of thousands of DNA samples in a robust and inexpensive manner. This MGM technology is completely scalable and should provide rapid and accurate DNA storage and retrieval capacity for the foreseeable future.