A community-based strategy for improving asthma management and outcomes for preschoolers.

Although almost one in ten (8.6%) preschool children has been diagnosed with asthma, few asthma management programs are designed for parents of preschool children. The Asthma Basics for Children program addressed this need in 2003-2008 by implementing a multi-layered approach that offered educational activities to center staff, parents, and children and PACE training to physicians in 31 Northern Manhattan daycare centers. Following program participation, 85% of parents reported reducing their child's triggers, 89% said it was easier to talk to their child's physician, and 80% were confident in their ability to manage their child's asthma. Children's any daytime symptoms dropped from 78% to 42%, any nighttime symptoms from 81% to 49%, any daycare absences from 56% to 38%, any asthma-related emergency department (ED) visits from 74% to 47%, and any asthma-related hospitalizations from 24% to 11% (p < .001 for all differences). Outcomes varied by level of exposure. In the Center-Only group (no parent participation), the only reduction was from 19% to 10% (McNemar = 3.77, p = .052) in hospitalizations. Children whose parents participated in the program had significant reductions in daycare absences (62% to 38%, McNemar = 11.1, p < .001), ED visits (72% to 43%, McNemar = 19.2, p < .001), and hospitalizations (24% to 11%, McNemar = 5.54, p = .018). Children whose parents and healthcare provider participated had the greatest improvements with asthma-related daycare absences dropping from 62% to 32% (McNemar = 9.8, p = .001), ED visits from 72% to 37% (McNemar = 14.4, p < .001), and hospitalizations from 35% to 15% (McNemar = 8.33, p = .003). This study demonstrates that a multi-layered approach can improve asthma outcomes among preschoolers with a combination of parent and provider education having the greatest impact.

Hydrogel-immobilized antibodies for microfluidic immunoassays: hydrogel immunoassay.

The integration of immunoassays in microfluidic devices is a rapidly developing research area combining the power of immunoassays with the inherent benefits of microfluidics. Here, a general overview of microfluidic-based immunoassays is presented along with a method for immobilizing antibodies in polyacrylamide gel plugs set in microfluidic channels. These antigen-specific hydrogels can be rapidly formed by photopolymerizing monomer solutions mixed with antibodies or other large proteins. The resulting antigen-specific hydrogels contain pore sizes appropriate for physical entrapment of large antibodies while remaining permeable to smaller proteins. The open structure of these hydrogels enables the capture and concentration of target antigens present at low concentrations. Such physical entrapment provides a conceptually simple method of immobilization compared with immobilization of proteins on surfaces and offers advantages such as resistance to chemical and thermal denaturation.

Capillary and microelectrophoretic separations of ligase detection reaction products produced from low-abundant point mutations in genomic DNA.

Capillary gel electrophoresis (CGE) and polymer-based microelectrophoretic platforms were investigated to analyze low-abundant point mutations in certain gene fragments with high diagnostic value for colorectal cancers. The electrophoretic separations were carried out on single-stranded DNA (ssDNA) products generated from an allele-specific ligation assay (ligase detection reaction, LDR), which was used to screen for a single base mutation at codon 12 in the K-ras oncogene. The presence of the mutation generated a ssDNA fragment that was >40 base pairs (bp) in length, while the primers used for the ligation assay were <30 bp in length. Various separation matrices were investigated, with the success of the matrix assessed by its ability to resolve the ligation product from the large molar excess of unligated primers when the mutant allele was lower in copy number compared to the wild-type allele. Using CGE, LDR product models (44 and 51 bp) could be analyzed in a cross-linked polyacrylamide gel with a 1000-fold molar excess of LDR primers (25 bp) in approximately 45 min. However, when using linear polyacrylamide gels, these same fragments could not be detected due to significant electrokinetic biasing during injection. A poly(methylmethacrylate) (PMMA) microchip of 3.5 cm effective column length was used with a 4% linear polyacrylamide gel to analyze the products generated from an LDR. When the reaction contained a 100-fold molar excess of wild-type DNA compared to a G12.2D mutant allele, the 44 bp ligation product could be effectively resolved from unligated primers in under 120 s, nearly 17 times faster than the CGE format. In addition, sample cleanup was simplified using the microchip format by not requiring desalting of the LDR prior to loading.

BioMEMS using electrophoresis for the analysis of genetic mutations.

Biomedical microelectromechanical systems (BioMEMS) are rapidly emerging in many areas of genetic analysis. These devices demonstrate potential for rapid analysis using modular components capable of sample purification, amplification, mutation discrimination and detection on small, portable point-of-care instruments. Here, various approaches to genetic mutation detection and the modern analysis platform, capillary electrophoresis, will be briefly reviewed. Microfluidic devices will be discussed in relation to fabrication techniques, mutation detection using simple electrophoretic separations, multiplexed designs and modular functionalities, as well as challenges and issues surrounding this technology.

Microfluidic devices fabricated in poly(methyl methacrylate) using hot-embossing with integrated sampling capillary and fiber optics for fluorescence detection.

High-aspect-ratio microstructures have been prepared using hot-embossing techniques in poly(methyl methacrylate) (PMMA) from Ni-based molding dies prepared using LIGA (Lithographie, Galvanoformung, Abformung). Due to the small amount of mask undercutting associated with X-ray lithography and the high energy X-ray beam used during photoresist patterning, deep structures with sharp and smooth sidewalls have been prepared. The Ni-electroforms produced devices with minimal replication errors using hot-embossing at a turn around time of approximately 5 min per device. In addition, several different polymers (with different glass transition temperatures) could be effectively molded with these Ni-electroforms and many devices (>300) molded with the same master without any noticeable degradation. The PMMA devices consisted of deep and narrow channels for insertion of a capillary for the automated electrokinetic loading of sample into the microfluidic device and also, a pair of optical fibers for shuttling laser light to the detection zone and collecting the resulting emission for fluorescence analysis. Electrophoretic separations of double-stranded DNA ladders Phi X174 digested with Hae III) were performed with fluorescence detection accomplished using near-IR excitation. It was found that the narrow width of the channels did not contribute significantly to electrophoretic zone broadening and the plate numbers generated in the extended length separation channel allowed sorting of the 271/281 base pair fragments associated with this sizing ladder when electrophoresed in methylcellulose entangled polymer solutions. The dual fiber detector produced sub-attomole detection limits with the entire detector, including laser source, electronics and photon transducer, situated in a single box measuring 3'' x 10" x 14".