Characterisation of adhesive bonds for ingestible biomedical applications

Most wireless endoscopic capsules use optical imaging as their sole diagnostic modality. The integration of ultrasound into such ingestible medical devices provides a safe method of imaging beneath the surface thereby complementing the data obtained by optical imaging and enabling earlier diagnosis of gastrointestinal disease. However, temperature constraints associated with piezoelectric transducers can hinder the bonding of these devices and their resulting integration with electronics. Adhesive bonding is one possible solution but there is little information available on the suitability of many common adhesives when subjected to the wide pH range along the gastrointestinal tract. This paper presents initial results obtained from the characterisation and optimisation of the automatic dispensing process for various adhesives using a MAT 6400 die bonder. The article also provides information on the effect of simulated gastrointestinal solution on the strength of several common adhesives.