Printing and Patterning Techniques

A comparison of the above-reviewed membrane deposition and patterning techniques might at first suggest that photolithography seems very promising for biosensor development, but the chemistry is complex and very few results have been published to date. Since a lot more development work is needed, most developers have opted for screen printing, i.e. the safest and least capital expensive approach. 

For microelectronic biosensors a further problem is the immobilization procedure of enzymes. Again different approaches were tried including drop-on techniques [61], ink-jet printing [68], spray techniques [62], electropolymerization [64], lift-off techniques [63,66] and photolithographically patterned enzyme membranes [65]. 

Unconventional patterning techniques, such as soft lithography (e.g., microcontact printing), nanoimprint lithography, and scanning probe lithography, are increasingly used for the cost-effective fabrication of nanostructures. They are particularly attractive because they can be performed even without cleanroom facilities. 

For applications that demand sub-20 pm resolution, it may be possible to combine micro-contact and thermal transfer printing high resolution source/drain electrodes printed with pCP could be used with other components that are patterned by thermal transfer. These and other strategies that combine and match different patterning techniques may provide an attractive means of building plastic circuits. 

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