Development of a sensitive, low-cost and user-friendly centrifugal microfluidic cartridge for multi-analyte environmental monitoring

This paper describes the development of a simple centrifugal cartridge for the analysis of nitrite, ammonia and phosphate from a water sample. The cartridge is operated in combination with the Centrifugal Microfluidic Analysis System (CMAS)[1] which incorporates rotational control with optical and communication components for portable analysis of environmental and biomedical samples[1,2]. An LED and a photodiode allow colorimetric determination of specific analytes depending on which reagent-based analytical method is employed. Bluetooth wireless communications provides automatic uploading of analytical data to cloud-based information systems. Microfluidic discs consisting of three PMMA (Poly(methyl methacrylate)) layers bonded together by two PSA (Pressure Sensitive Adhesive) layers were prepared. The sample was transported from a single chamber to three aliquoting chambers at a low rotational frequency prior to the actuation of dissolvable film valves[3] at an increased rotational frequency to facilitate sample transport to reaction/detection chambers. Ammonia standards were analysed using a modified Berthelot method, the stannous chloride method was used to detect orthophosphate levels while a diazotization method was employed to determine nitrite concentration. Photodiode analysis on the CMAS platform obtained LOD’s of 0.233 ppm for ammonia and 0.189 ppm for orthophosphate and 50 ppb for nitrite

Development of a portable multi-parameter centrifugal microfluidic analysis system (cmas) for water quality monitoring

In this paper we report the development of a multi-parameter low-cost (< 100 EUR) portable Centrifugal Microfluidic Analysis System (CMAS) for the in-situ colorimetric analysis of nutrients. Microfluidic discs consisting of three PMMA (Poly(methyl methacrylate)) layers bonded together by two PSA (Pressure Sensitive Adhesive) layers were prepared. A 3D-printed housing was produced for hosting the microfluidic discs which incorporated a low-cost optical sensor for colorimetric detection and a motor which generated the centrifugal force necessary to carry out the tests. Limits of detections of 0.233 ppm, 0.189 ppm and 0.050 ppm were obtained for ammonia, orthophosphate and nitrite respectively

Serotonin receptor mechanisms mediate the discriminative stimulus properties of the atypical antipsychotic clozapine in C57BL/6 mice

Rationale: The atypical antipsychotic drug (APD) clozapine (CLZ) has been shown to have a robust discriminative cue in rats, pigeons, and monkeys in two-choice drug discrimination procedures. Objectives: The present study determined whether a two-choice drug discrimination procedure with CLZ could be established in C57BL/6 mice and whether this procedure could distinguish between atypical and typical APDs. Methods: C57BL/6 male mice were trained to discriminate 2.5 mg/kg CLZ from vehicle in a two-lever drug discrimination procedure. Results: Generalization testing with CLZ produced full substitution at the 2.5- and 5.0-mg/kg doses with an ED(50) of 1.14 mg/kg. The atypical APDs olanzapine (ED(50)=0.24 mg/ kg), risperidone (ED(50)=0.072 mg/kg), and ziprasidone (ED(50)=0.33 mg/kg) fully substituted for CLZ's discriminative cue, while the typical APD haloperidol failed to substitute for CLZ. Generalization testing with selective ligands showed that the serotonin (5-HT)(2A/2B/2C) antagonist ritanserin fully substituted for CLZ (ED(50)=2.08 mg/ kg) and that the 5-HT receptor agonist quipazine significantly attenuated CLZ's discriminative cue without disrupting response rates. The muscarinic receptor antagonist scopolamine, the dopamine agonist amphetamine, and the 5-HT agonist quipazine failed to substitute for CLZ. Conclusions: These results demonstrated that antagonism of 5-HT receptors plays an important role in mediating the discriminative stimulus properties of the atypical APD CLZ in C57BL/6 mice. The atypical APDs olanzapine, risperidone, and ziprasidone fully substituted for CLZ, while the typical APD haloperidol did not. These results suggest that CLZ drug discrimination in C57BL/6 mice may be an effective preclinical behavioral assay for screening atypical from typical antipsychotic drugs