RESUMO
BACKGROUND: The tagging system is based on a small, electronic, wireless, laser-light-activated microtransponder named "p-Chip." The p-Chip is a silicon integrated circuit, the size of which is 600 µm × 600 µm × 100 µm. Each p-Chip contains a unique identification code stored within its electronic memory that can be retrieved with a custom reader. These features allow the p-Chip to be used as an unobtrusive and scarcely noticeable ID tag on glass slides and tissue cassettes. METHODS: The system is comprised of p-Chip-tagged sample carriers, a dedicated benchtop p-Chip ID reader that can accommodate both objects, and an additional reader (the Wand), with an adapter for reading IDs of glass slides stored vertically in drawers. On slides, p-Chips are attached with adhesive to the center of the short edge, and on cassettes - embedded directly into the plastic. ID readout is performed by bringing the reader to the proximity of the chip. Standard histopathology laboratory protocols were used for testing. RESULTS: Very good ID reading efficiency was observed for both glass slides and cassettes. When processed slides are stored in vertical filing drawers, p-Chips remain readable without the need to remove them from the storage location, thereby improving the speed of searches in collections. On the cassettes, the ID continues to be readable through a thin layer of paraffin. Both slides and tissue cassettes can be read with the same reader, reducing the need for redundant equipment. CONCLUSIONS: The p-Chip is stable to all chemical challenges commonly used in the histopathology laboratory, tolerates temperature extremes, and remains durable in long-term storage. The technology is compatible with laboratory information management systems software systems. The p-Chip system is very well suited for identification of glass slides and cassettes in the histopathology laboratory.
RESUMO
Collecting information about biochemical processes occurring inside a single cell or embryo is traditionally done either using fluorescent dyes with microscopy or via microelectrode voltage-clamp techniques. This paper demonstrates that a more direct method - transmission of information using an electronic chip implanted in an embryo - is feasible. A light-activated microtransponder with dimensions 250 µm × 250 µm × 100 µm (a "p-Chip") was implanted into a blastula-stage frog (Xenopus laevis) embryo. To implant the chip, a small slit is made in the blastocoel roof with an electrolytically-sharpened tungsten needle, and the p-Chip is inserted using fine forceps. The chip is activated when illuminated by a 60 mW focused laser beam, which causes the p-Chip to send its numeric ID to a nearby receiver. At no time during signal transmission does a wire or other type of object come in contact with or penetrate the epidermal layer covering the p-Chip. The embryo survives the procedure, extruding the chip after approximately 3 h. The method shows promise for studies including voltage potential, pH and other parameters.
