Novel LTCC-potentiometric microfluidic device for biparametric analysis of organic compounds carrying plastic antibodies as ionophores: Application to sulfamethoxazole and trimethoprim

Monitoring organic environmental contaminants is of crucial importance to ensure public health. This requires simple, portable and robust devices to carry out on-site analysis. For this purpose, a low-temperature co-fired ceramics (LTCC) microfluidic potentiometric device (LTCC/ POT) was developed for the first time for an organic compound: sulfamethoxazole (SMX). Sensory materials relied on newly designed plastic antibodies. Sol–gel, self-assembling monolayer and molecular-imprinting techniques were merged for this purpose. Silica beads were amine-modified and linked to SMX via glutaraldehyde modification. Condensation polymerization was conducted around SMX to fill the vacant spaces. SMX was removed after, leaving behind imprinted sites of complementary shape. The obtained particles were used as ionophores in plasticized PVC membranes. The most suitable membrane composition was selected in steady-state assays. Its suitability to flow analysis was verified in flow-injection studies with regular tubular electrodes. The LTCC/ POT device integrated a bidimensional mixer, an embedded reference electrode based on Ag/AgCl and an Ag-based contact screen-printed under a micromachined cavity of 600 m depth. The sensing membranes were deposited over this contact and acted as indicating electrodes. Under optimum conditions, the SMX sensor displayed slopes of about −58.7 mV/decade in a range from 12.7 to 250 g/mL, providing a detection limit of 3.85 g/mL and a sampling throughput of 36 samples/h with a reagent consumption of 3.3 mL per sample. The system was adjusted later to multiple analyte detection by including a second potentiomet-ric cell on the LTCC/ POT device. No additional reference electrode was required. This concept was applied to Trimethoprim (TMP), always administered concomitantly with sulphonamide drugs, and tested in fish-farming waters. The biparametric microanalyzer displayed Nernstian behaviour, with aver-age slopes −54.7 (SMX) and +57.8 (TMP) mV/ decade. To demonstrate the microanalyzer capabilities for real applications, it was successfully applied to single and simultaneous determination of SMX and TMP in aquaculture waters.The authors acknowledge the financial support from FCT, Fundacão para a Ciência e Tecnologia/FEDER (project PTDC/AGR-AAM/68359/2006). Oneofus (Almeida SAA) is grateful to FCT for the PhD Grant (SFRH/BD/42509/2007).Publicad

Differential expression of laminin isoform (a2), integrins (a3B1 and a6B4) and cytokeratin 20 in H. pylori gastritis

The expression of laminin-l chains (131 and yl), laminin-2 (merosin), integrin receptors to laminin (a3131 and a6134) and cytokeratin (CK20) were studied by immunohistochemical methods in gastric biopsies from antrum of 25 patients. H. pylori gastritis was found in 19 cases and intestinal metaplasia (IM) in four from these 19. Another 13 biopsies, all with IM were immunostained to laminin-2. Laminin-l chains in normal and gastritis areas without 1M were expressed as a strong, linear and continuous deposit in the basement membranes of the superficial and glandular epithelium. In metaplastic glands the reactivity to laminin-l chains was decreased. Merosin was discontinuous when a moderate to accentuated H. pylori glandular colonization was present. Samples with IM were negative to laminin- 2. The a3131 and a6134 integrins were negative only in IM gastric biopsies. The CK20 immunoreactivity was strong and homogeneous in the cells at the tip and the upper portion of foveolae in normal areas and in gastritis with IM the reactivity to CK 20 was heterogeneous. A differential expression of laminin isoforms is related to inflammation and subsequent IM caused by H, pylori. The alterations of a3131 and a6D4 parallel both modifications in merosin and CK20 expression in H. py10r.i chronic gastritis

Innovative sensors for age-related diseases

Point-of-care diagnosis is evolving together with the fast development in terms of detection and quantification ability of the sensing techniques. This chapter covers 5 different topics of innovative (bio)sensors that were designed with the aim of giving new insights to overcome many of the hurdles that still impair the widespread use of portable sensing technology. Novelty was achieved by applying inexpensive materials with tuned functions and refined recognition towards biomarkers of various age-related pathologies. Diverse strategies were followed in order to attain improved properties on relevant parameters of sensor performance such as selectivity, sensitivity, biocompatibility and autonomy. Thus, the foreseen biomedical applications are vast.The authors gratefully acknowledge the financial support from IBEROS project (Instituto de Bioingeniería en Red para el Envejecimiento Saludable, INTERREG POCTEP/0245_IBEROS_1_E) supported by FEDER, also within the cooperation region of Galicia/Spain and North of Portugal. CBQF also acknowledges the scientific collaboration under the FCT project UID/Multi/50016/2019