Maria Magliulo

Bioluminescent Biosensors Based on Genetically Engineered Living Cells in Environmental and Food Analysis

Abstract The development of cost‐effective on‐site analytical methods is an urgent need to monitor food safety and detect environmental pollution. Whole‐cell biosensors have shown the potential to complement both laboratory‐based and on‐field analytical methods for the detection of general stress conditions, cyto‐ and genotoxic compounds, organic xenobiotics and metals, as well as endocrine disrupting compounds. The sensitive and rapid detection of biochemiluminescence, combined with the specificity or selectivity of gene regulation in living cells, offers significant advantages over conventional analytical methods, providing data on the bioavailability and biological activity of contaminants; this information is very valuable for risk assessment purposes the identification of suitable remediation systems. Moreover, complex pretreatment of the environmental sample, as in usual chemical analysis techniques, is often not necessary for biosensor measurements.

A new point-of-care portable immunosensor for non-invasive assessment of oro-ileal transit time by oral fluid tauroursodeoxycholate measurement after its oral load

A non-invasive test for oro-ileal transit time (OITT) evaluation was developed, based on the measurement of tauroursodeoxycholic acid (TUDCA) oral fluid concentration profile after its oral administration. Exploiting the fact that TUDCA is actively absorbed only in the ileum, OITT is measured as the time corresponding to TUDCA maximum oral fluid concentration (tmax). To measure oral fluid TUDCA concentration in a point-of-care setting, an ultrasensitive portable immunosensor was developed, based on a competitive chemiluminescent enzyme immunoassay (CL-EIA), using immobilized anti-TUDCA antibody and an ursodeoxycholic acid (UDCA)-peroxidase conjugate as tracer, detected by enhanced chemiluminescence employing a portable charge-coupled device (CCD)-based device. The test was validated in 24 healthy subjects before and after treatment with Loperamide, a drug that increases OITT. The developed CL-EIA was accurate and precise, with a LLOQ of 50 pmol L(-1). The measured OITT for healthy subjects (291 ± 50 min) was fairly well correlated with OITT values obtained by measuring TUDCA in serum (r=0.89). An increased OITT was observed in all the studied subjects after Loperamide treatment. The CL immunosensor can be employed directly in gastroenterology and paediatric units and it can thus represent a new non-invasive simple test for OITT evaluation in a point-of-care setting, with improved diagnostic utility.