Advanced printing and deposition methodologies are revolutionising the way biological molecules are deposited and leading to changes in the mass production of biosensors and biodevices. This revolution is being delivered principally through adaptations of printing technologies to device fabrication, increasing throughputs, decreasing feature sizes and driving production costs downwards. This review looks at several of the most relevant deposition and patterning methodologies that are emerging, either for their high production yield, their ability to reach micro- and nano-dimensions, or both. We look at inkjet, screen, microcontact, gravure and flexographic printing as well as lithographies such as scanning probe, photo- and e-beam lithographies and laser printing. We also take a look at the emerging technique of plasma modification and assess the usefulness of these for the deposition of biomolecules and other materials associated with biodevice fabrication.

This review covers in detail the complexity of human breath, how the body metabolizes ammonia, clinical conditions which are directly related to the regulation of ammonia concentration, and analysis of current techniques that are capable of detecting breath ammonia. Focusing on these areas provides the information needed to develop a breath ammonia sensor for monitoring dysfunction of the human body. Human breath has been broken down into its key components which are necessary for proper understanding of what to look for when attempting to isolate volatile organic compounds. A pathway has been shown which explains the origin of ammonia in the body and how it is processed within a healthy system. Following this, the hazards of several dysfunctions related to the broken ammonia pathway have been discussed. It is essential that technicians have knowledge of these inner workings of the human body along with current technology. Thus, the advantages and disadvantages of techniques from chemical ionization, gas chromatography, laser spectroscopy, and chemical sensing have been discussed.