Development and evaluation of a multianalyte optical fiber imaging biosensor platform using contact-based microdispensing technology

The following dissertation describes the development and evaluation automated contact-based microdispensing system for creating optical fiber based imaging sensor for remote and in-situ analyses. The work described herein includes a discussion of fiber sensor fabrication techniques both past and present; proof-of-concept demonstration of non-contact microdispensing fabrication methods; the development and evaluation of a custom contact-based microdispensing robotics platform for fabricating imaging sensors; the development of indicator chemistries and polymer-based chemistries for printing; and the development and characterization of the first multianalyte imaging sensor for detecting MMP enzymes in solution.; Initially, optical fiber based imaging pH sensors were fabricated using a non-contact microdispensing system to determine the feasibility of using inkjet printing technologies for creating sensors. A 6-around-1 pattern of micron-sized epoxy-based droplets (i.e. microdots) containing a fluorescent pH sensitive indicator were "printed" on optical fiber image guide fibers and evaluated in terms of physical and optical properties. This is discussed in Chapter 3. The development and evaluation of an automated contact-based microdispensing system for fabricating sensors is described in Chapter 4. The design of the system hardware and software is discussed in detail along with examples of the printing capabilities of the completed system. The details of chemistries developed for the contact-based microdispensing system are described in Chapter 5. This included the development of UV curable pin printable hydrogel formulations. In Chapters 6 and 7, optical fiber based sensors for pH and enzyme sensing are demonstrated, respectively. The initial work focused on development of a pH sensor (Chapter 6) which is combined with the enzyme sensor (Chapter 7) to create the first optical fiber based enzyme sensor, imaging or otherwise. The final chapter is devoted to a discussion of key issues and provides a roadmap for future work on this subject, as well as a possible application. In addition, an appendix is included to provide detailed discussion on optical fiber preparation and fiber surface functionalization methods developed specifically for the contact-based printing technology.