Concanavalin A for in vivo glucose sensing: a biotoxicity review

Over the last two decades there as has been surging scientific interest in employing the glucose- and mannose-specific lectin Concanavalin A (ConA) in affinity biosensors for in vivo glucose monitoring in diabetics. Numerous research groups have successfully shown in in vitro and in vivo studies that ConA-based affinity sensors can monitor glucose very accurately and reproducibly over many months, making ConA-based sensors an extremely interesting prospect for long-term implantation in humans. Despite this progress, there remains concern over the safety of ConA, which has widely been reported as a toxin in the literature. In this article, we review in vitro and in vivo studies related to ConA toxicity in order to assess the health risks posed by ConA in the context of an implantable biosensor. Based on the wealth of information available and on data from our own studies, we can conclude that the site of implantation (subcutaneous skin tissue) and the small amount of ConA (<10 microg/microl) being used in implantable glucose-sensitive detector devices like those proposed by various research groups would pose little or no health risk to its bearer even in the event of unexpected sensor rupture.