This work describes the successful design, fabrication and implementation of a generic, optimised immunosensor. The first stage of the work was the establishment of the techniques required to develop an effective immunosensor, in particular, antibody immobilisation strategies, patterning methods and excitation, detection and analysis systems. Once developed, these techniques were integrated and employed, in conjunction with a planar glass substrate, to obtain dose response curves for BSA/antiBSA antibody assays. In parallel work, theoretical predictions relating to fluorescence emission were verified. It was shown that redirection of surface-confined fluorescence results in the enhancement of the fluorescence capture efficiency, and also that it is possible to discriminate between fluorescence originating at the surface and fluorescence originating from the bulk solution above the surface. These results have important implications for the design of fluorescence-based optical sensor platforms and were used in the design and fabrication of structured polymer biochips with enhanced fluorescence capture efficiency. The final stage of the work presented here was the incorporation of the structured platforms with the immunosensmg systems established previously, in order to produce an optimised, generic, optical immunosensor. The replacement of the planar glass substrate with the enhanced polymer platform necessitated the adaptation of several of the systems. In particular, various antibody to polymer immobilisation strategies were investigated, with the optimum used to perform a full BSA/antiBSA antibody assay. A minimum detectable signal considerably lower than that of the planar immunosensor was achieved, thus validating the optimisations. The ability of this enhanced immunosensor to detect significantly lower levels of fluorescence has important implications for sensing applications where analytes are toxic in low concentrations or are only available in small quantities, with these situations occurring in a wide range of areas including health care, food safety and early-warning biological warfare agent detection.