Both Fluoview 300 and MiiM 1.8 base their measurements on signal intensity integrated over a circular area. The duplex assay paves the way for a future quantitative multiplex assay, which analyses several prostate malignancy biomarkers simultaneously. Keywords: quantitative, antibody microarray, total and free PSA, prostate malignancy biomarker, duplex assay, porous silicon 1. Intro Protein or antibody microarrays are often proposed as tools GPR35 agonist 1 for high-throughput screening for analyzing thousands of biomarkers simultaneously. In the pharmaceutical market, high-throughput platforms are an important way to reduce assay costs. The parallel process makes it possible to drastically reduce reagent usage compared to microtiter plate types. Protein chip technology is becoming an increasingly founded technique, not only for characterizing specific proteins and even proteomes, but also for medical applications. Although routine medical use of microarray technology still is in its early phase, antibody microarrays have been developed for a number of medical diagnostic applications [1-6]. Until now, most protein microarray applications have been utilized for qualitative analysis, for example to profile thousands of proteins, to quickly assess the specificity of an antibody [7, 8] or to globally analyze protein phosphorylation [9]. However, limited attempts have been put into the TUBB3 development of a quantitative approach. Often, protein microarrays are used for comparing the levels of large units of proteins in two different samples [10-13]. Reverse-phase protein microarrays have been successfully used to monitor biomarkers in malignancy cell lines or in laser-captured microdissections from different malignancy phases [1, 4]. However, this technique must be considered semi-quantitative, although Pollard et al [5] explained that a revised format of the technique was quantitative. For true quantitative analysis, a standard curve could be used in a similar way as with a standard microtiter plate format [14-16]. Most of the existing publications on quantitative analysis have not yet been shown on larger individual cohorts. Probably the most considerable study (Knickerbocker et al 2007) was based on cytokine measurements in 468 samples from kidney dialysis GPR35 agonist 1 individuals. It should be mentioned that the spot density was larger than the one we present in this paper. Relating to Knickerbocker et al [17] a center-to-center spacing of 250-350 m was used as compared to 150 m in the arrays explained herein. The reason why our assay can apply such a small center-to-center spacing is the nanostructured hydrophobic surface behavior (yet hydrophilic surface chemistry) of our in-house formulated porous silicon surfaces, causing an extremely small contact area for the dispensed droplets within the chip. The medical focus of this work is definitely improvement of prostate malignancy diagnostics. Prostate-specific antigen (PSA) concentration in plasma is definitely widely used GPR35 agonist 1 as an indication of prostate disease. However, the diagnostic specificity is definitely a concern, because an increased PSA value might be due to benign prostate hyperplasia (BPH) or prostatitis rather than prostate malignancy. Before prostate malignancy can be diagnosed or excluded, the patient needs to endure painful prostate biopsy. In addition, some prostate cancers progress very slowly and the patient is unlikely GPR35 agonist 1 to pass away of or have any physical complications from your cancer. To improve prostate malignancy diagnostics, fresh biomarkers are wanted to distinguish BPH from prostate malignancy and also indolent from rapidly developing cancer. One way to improve the diagnostics might be simultaneous analysis of multiple biomarkers, and microarray technology is definitely.