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In this work, a series of silicon chips containing sputtered gold electrodes were first coated with a self-assembled monolyayer (SAM) of lipoic acid. The same electrodes were then functionalized by using a Ru(bpy)3 2+ amine derivative, bis(2,2‘-bipyridine)-[4-(4‘-methyl-2,2‘-bipyridin-4-yl)aminobutyl] ruthenium bis(hexafluorophosphate). Its synthesis and purification is reported in detail for the first time. A two-step preparation of the emitting layer increased both the compactness of the SAM and the density of Ru emitting sites, as evidenced by electrochemiluminescence (ECL) and X-ray photoelectron spectroscopy (XPS) investigations. This approach enables the preparation of reproducible and compact ECL-active monolayers containing bulky molecules without the need for preliminary purification of the labeled surfactant. The occurrence of the coupling surface reaction was detected by monitoring the electrochemically induced luminescence from the modified electrode, in the presence of tripropylamine as oxidative co-reactant, and was confirmed by time-of-flight secondary ion mass spectrometry and XPS measurements.

In this study we analyzed the surface properties of different silicon-based materials used for micro-electro-mechanical systems (MEMS) production, such as thermally grown silicon oxide, plasma-enhanced chemical vapor deposition (PECVD)-treated silicon oxide, reactive-ion etch (RIE)-treated silicon oxide, and Pyrex. Substrates were characterized by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) to define the surface chemical and morphological properties, and by fluorescence microscopy to directly assess the absorption of the different polymerase chain reaction (PCR) components. By using microchips fabricated with the same materials we investigated their compatibility with PCR reactions, exploiting the use of different enzymes and reagents or proper surface treatments. We established the best conditions for DNA amplification in silicon/Pyrex microdevices depending on the type of device and fabrication method used and the quality of reagents, rather than on the passivation treatment or increment in standard Taq polymerase concentration.

Aim: this study evaluates the analytical and clinical performances of a new technology, CompleXima HCC Biochip, for the simultaneous serum measurement of alpha-fetoprotein-IgM (AFP-IgM) and squamous cell carcinoma antigen-IgM (SCCA-IgM). Methods: AFP- and SCCA-IgM were measured by both ELISA and CompleXima HCC Biochip in 39 blood donors and in 174 patients (102 liver cirrhosis-LC-and 72 hepatocellular carcinoma-HCC). Results: the intra-assay coefficients of variation were lower than 12% and the inter-assay variations comprised between 14% and 21%. The linearity interval for the CompleXima HCC Biochip was 50-300 AU mL-1 for AFP-IgM and SCCA-IgM. The comparison between the prototype and the ELISA test was studied by using the Bland-Altman method and Passing-Bablok regression analyses. Passing-Bablok showed that the Biochip under-estimated AFP-IgM (Intercept A: -165.06; 95% CI: -313.11 to -51.32) and overestimated SCCA-IgM (Intercept A: 26.83; 95% CI: 14.47-35.86) with respect to ELISAs. Both biomarkers were higher in LC and HCC with respect to controls (p < 0.001) with no difference between LC and HCC (p = 0.864 for AFP-IgM and p = 0.214 for SCCA-IgM). The thresholds for AFP-IgM and SCCA-IgM were calculated by means of ROC curves, fixing the specificity at 95%. The sensitivity of AFP-IgM and SCCA-IgM associated with CompleXima in detecting patients with liver diseases was 47% and 46%, respectively. The combined evaluation of macrocomplexes with CompleXima in diagnosing HCC with respect to LC was associated with a sensitivity of 51.4% and a specificity of 48%. Conclusions: AFP-IgM and SCCA-IgM increase in chronic liver disease. The prototype CompleXima HCC Biochip allows their measurement with a good analytical reproducibilit

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