Nucleic-acid-functionalized gold surfaces have been used extensively for he development of biological sensors. The development of an effective biomarker detection assay requires careful design, synthesis, and characterization of probe components, in this Feature Article, we describe fundamental probe development constraints and provide a critical appraisal of the current methodologies and applications in the field. We discuss critical issues and obstacles that impede the sensitivity and reliability of the sensors to underscore the challenges that must be met to advance the field of biomarker detection.