Abstract: The invention relates to a sensor for the in vivo measurement of an analyte, comprising a plurality of particles of suitable size such that when implanted in the body of a mammal the particles can be ingested by macrophages and transported away from the site of implantation, each particle containing the components of an assay having a readout which is an optical signal detectable transdermally by external optical means, and either each particles being contained within a biodegradable material preventing ingestion by the macrophages, or each particle being non-biodegradable. The invention relates to a process for the detection of an analyte using such a sensor, comprising implantation of the sensor into the skin of a mammal, transdermal detection of analyte using external optical means, degradation of the biodegradable material, ingestion of the particles by macrophages, and removal of the particles from the site of implantation by macrophages.

Abstract: The invention relates to a sensor for the in vivo measurement of an analyte, comprising a plurality of particles of suitable size such that when implanted in the body of a mammal the particles can be ingested by macrophages and transported away from the site of implantation, each particle containing the components of an assay having a readout which is an optical signal detectable transdermally by external optical means, and either each particles being contained within a biodegradable material preventing ingestion by the macrophages, or each particle being non-biodegradable.

Abstract: An assay implantation apparatus is provided comprising a sensor for use for the in vivo measurement of an analyte and means for implanting said sensor within an upper layer of the skin from which it is naturally ejected over time by growth of the skin and progressive replacement of the outer layer of the skin. The sensor may comprise microparticles containing a chemical assay system into which an analyte may diffuse from intercellular fluid and which assay system can be interrogated remotely by a light signal and a fluorescence sensor.

Abstract: An assay implantation apparatus is provided comprising a sensor for use for the in vivo measurement of an analyte and means for implanting said sensor within an upper layer of the skin from which it is naturally ejected over time by growth of the skin and progressive replacement of the outer layer of the skin.