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In this work, a novel paper-based analytical device (PAD) coupled to LED-induced fluorescence (LIF) detection (fPAD) for the rapid, selective, and sensitive quantification of phenylalanine (Phe) in neonatal samples was developed. The enzymes phenylalanine dehydrogenase (PheDH) and diaphorase were immobilized on a paper microzone previously modified with zinc oxide nanoparticles (ZnONPs) coated with chitosan (CH-ZnONPs). Phe was extracted from the blood spots collected from samples on a filter paper and was mixed with nicotinamide adenine dinucleotide (NAD+) and resazurin. Then the mixture was deposited on the reaction microzone of the fPAD where PheDH converts Phe and NAD+to phenylpyruvate and NADH, respectively. Finally, NADH was oxidized by diaphorase with the consequent reduction of resazurin to resorufin. The latter was detected by LIF using an excitation wavelength of 535 nm and an emission wavelength of 580 nm using a synchronized video microscope. We compared the responses of the PADs with and without nanomaterials to demonstrate the improved analytical performance of the developed devices. For this, the PADs were modified with the same concentration of horseradish peroxidase (HRP). The fluorescent signal obtained from the PADs with nanomaterials was higher than that of the unmodified PADs. Our method exhibited within- and between-assay variation coefficients below 5.23% and 6.67%, respectively. The detection limit obtained by the developed device was 0.125 μM. The proposed fPAD allowed the simple, rapid, low-cost, and sensitive detection of Phe in neonatal blood samples.

Percutaneous ultrasonography (perc-US) and magnetic resonance enterography (e-MR) are the present standards for staging patients with Crohn’s disease (CD). However, intraoperative data still have some discrepancies with preoperative ones. The contribution of intraoperative ultrasonography (IOUS) has never been evaluated. Sixty-five consecutive patients scheduled for ileal/colonic resection for CD between 2010 and 2014 were prospectively enrolled. All patients had perc-US, e-MR and IOUS. Data from different imaging modalities were compared. The reference standard was the final pathology. Surgery was scheduled because of intestinal obstruction (n= 31 patients), inflammatory mass (n= 21), fistula (n= 10), or abdominal pain/sepsis (n= 3). Fourteen (21.5%) patients had a major discrepancy between preoperative and intraoperative data that required a modification of the surgical planning (five additional ileal lesions, three unknown ileo-sigmoid fistulas, and six not confirmed CD sites). IOUS correctly staged CD in all but one patients (missed ileo-colonic fistula). Pathology data differed from Perc-US data in 13 (20%) patients, from e-MR data in 14 (21.5%), and from IOUS data in one (1.5%). The sensitivity of Perc-US, e-MR and IOUS was: for the identification of CD sites 84.2%, 86.1%, and 100%; for the identification of stenoses 86.8%, 86.8%, and 100%; for the identification of fistulas 75.0%, 81.3%, and 93.8%, respectively. IOUS contributed to the surgical planning in 8 (12.3%) patients. IOUS is a safe, feasible and easy-to-perform procedure that optimizes staging of CD and, in some patients, helps to better define the treatment strategy. It could be helpful to face complex disease presentations on the basis of objective and reproducible data.

The gluten-free diet is a unique, effective treatment for different conditions related to gluten consumption. Therefore, it is crucial the availability of new methodologies for the sensitive and specific determination of gluten content in food samples. Herein, a screen printed electrode modified with carbon nanofibers coupled to a paper immunoaffinity platform was reported for the determination of gliadin in foods samples. The paper microzone covalently functionalized with specific anti-gliadin antibodies was placed on the modified electrode surface for the electrochemical determination of gliadin. The surface of the electrode modified with carbon nanofibers was characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV), which showed the improved sensitivity of the modified surface. The developed device was evaluated using different flour samples obtaining a favorable response. The calculated limit of detection for the device in analyzed samples was 0.005 mg kg−1and for the enzyme-linked immunosorbent assay was 1.5 mg kg−1. The coefficient of variation (CV) for the determination of 20 μg kg−1of gliadin was 4.11%. The disposable electrochemical sensor developed, represents an easy-to-use and low-cost strategy for the determination of gliadin in food samples.

To evaluate the short and long-term results of surgical treatment of calcifying chronic pancreatitis in our center.