RESUMO
We present a perspective on microsystems integration aspects for concurrent cellular and molecular sensing in a lab-on-a-chip device. While of interest for a range of applications, very few - narrowly focused - examples of such devices can be found in the literature. Here, we approach the challenge from a systems level, considering sensor integration both in parallel and in series. Our study is specifically geared toward schizophrenia treatment, where concurrent blood monitoring of the antipsychotic clozapine and white blood cells could lead to improved treatment outcomes. We evaluate the critical system components for either design, namely plasma skimming (parallel) and in-blood clozapine detection (series). We find that plasma skimming is infeasible, but for the first time demonstrate direct detection of clozapine in whole blood. With a corresponding series-integrated microsystem, we finally demonstrate downstream white blood cell analysis on the same samples using impedance cytometry. We thus present the first lab-on-a-chip device capable of label- and reagent-free concurrent sensing of cellular and molecular markers.
RESUMO
PREMISE OF THE STUDY: An efficient, effective DNA extraction method is necessary for comprehensive analysis of plant genomes. This study analyzed the quality of DNA obtained using paper FTA cards prepared directly in the field when compared to the more traditional cetyltrimethylammonium bromide (CTAB)-based extraction methods from silica-dried samples. METHODS: DNA was extracted using FTA cards according to the manufacturer's protocol. In parallel, CTAB-based extractions were done using the automated AutoGen DNA isolation system. DNA quality for both methods was determined for 15 non-agricultural species collected in situ, by gel separation, spectrophotometry, fluorometry, and successful amplification and sequencing of nuclear and chloroplast gene markers. RESULTS: The FTA card extraction method yielded less concentrated, but also less fragmented samples than the CTAB-based technique. The card-extracted samples provided DNA that could be successfully amplified and sequenced. The FTA cards are also useful because the collected samples do not require refrigeration, extensive laboratory expertise, or as many hazardous chemicals as extractions using the CTAB-based technique. DISCUSSION: The relative success of the FTA card method in our study suggested that this method could be a valuable tool for studies in plant population genetics and conservation biology that may involve screening of hundreds of individual plants. The FTA cards, like the silica gel samples, do not contain plant material capable of propagation, and therefore do not require permits from the U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) for transportation.
