Screen printing is one of most cost effective ways of manufacturing biosensors. A screen printed biosensor can be used for a single use application, as in the case of glucose strips, or used for continuous measurement, as in the case of continuous glucose meters used by Type 1 diabetics.
Whether a screen printed biosensor is used once, used continuously or re-used depends on the biosensor and the application. Disposable biosensors based on screen printed electrodes (SPE) has led to a revolution in the academic literature and in commercial products, the analytes that can be tested by SPE biosensors range from COVID-19, ions and small molecules to bacteria and parasites, please see adjacent buttons to see examples of these.
Disposable SPE biosensors are in line with the interest in portable testing devices, with the glucose meter being the archetypal portable biosensor, but as illustrated in the FoodSense button above this model of portable biosensing has expanded to more than just glucose and into markets other than just healthcare.
SPE offer a set of miniature electrodes in a small area and so this lends the use of SPE to sensing applications where it is an advantage to have a small sample volume. The classic integration of microfluidics and biosensing is the capillary fill SPE, where it is practical to detect sample volumes of less than 4 microlitres, these types of modified SPE also have the advantage of self filling.
Linked to their small size SPE biosensors lend themselves to be naturally multiplexed into a small package for multiple analyte detection from a single sample. For example six or more analytes can be detected in a cartridge no bigger than a credit card.
Activating or functionalizing a SPE to have specificity towards a bio-molecule of interest is can be fairly straightforward especially in the case of biosensors for ions and small molecules, such as sodium, potassium, pH, ammonium, glucose, lactate etc.
In most cases a molecule exists which when adhered to the SPE converts the working electrode into a biospecific electrode. In many cases a simple drop cast technique is sufficient to functionalise the electrode.
The real strength of SPE and the use of SPE for detecting macromolecules such as: DNA, RNA, antigens, proteins, antibodies, and pathogens such as viruses and bacteria is the wealth of academic literature. In these paper many describe how an biomolecule can be anchored to a SPE by coupling to a gold surface that is functionalized by a self-assembled monolayer.