The projected demands for safe, rapid and reliable technology for the storage and retrieval of genetic materials in medical, forensic and research applications are being addressed with increasing difficulty by many of the current technologies. We propose a new type of scalable microrepository whose sample preparation, identification and retrieval protocols offer an immediate and substantial improvement over the existing repository technologies in several important ways and can be configured to provide a self-replenishing feature for the stored genetic materials. The Microrepository for Genetic Materials (MGM) is based on a combination of optically encoded beads, silicon micromachining, mechanical bead handling and, optionally, on-bead PCR to replace the genetic material removed from the repository. A given sample of DNA is stored in a porous glass or polymer bead which possesses its own unique optical code. The beads are encoded with rare earth-based nanoparticles, which produce up to six resolvable visible emission bands, and can support thousands of resolvable optical signatures. The pooled encoded beads are randomly loaded into a micromachined silicon bead-holding fixture, which provides thousands of optically isolated wells, and the location of a given DNA sample within the holder determined from the optical signature of its bead. Using advanced bead handling technology from collaborator BioDot, Inc., a bead or bead slurry, identified from its x,y coordinates on the silicon storage plate is removed and placed into the destination location, presumably a PCR plate. If a portion of the sequence of the stored material is known, then the storage beads can contain a primer covalently bound to the bead. It has been shown that efficient PCR amplification can take place very rapidly within the pores of the bead with the resulting amplicon covalently bound to the bead via the primer. After amplification, the double stranded (ds) DNA on the bead can be used to amplify more material in solution by simply denaturing the dsDNA and allowing the dissociated single strand to diffuse out of the bead and into solution where it can be used as the template for PCR. Since one strand always remains covalently attached to the bead, the bead can be replaced into the original storage location ready for a future PCR amplification thereby providing a perpetually filled repository. Since the DNA is stored in rigid pores <300 nm in diameter, bacteria can not enter the pores and it may be possible to store some samples at room temperature. ? ? ?
