12 research outputs found
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