A sequential injection capillary immunoassay system (SI-CI) was developed to automate the multi-step competitive bioassay procedures for hyaluronan (HA), a potential biomarker for liver and cancer diseases. Biotinylated HA-binding proteins (b-HABPs), anti-biotin conjugated with horseradish peroxidase (anti-b-HRP) and substrate 3,3',5,5' tetramethylbenzidene (TMB) were employed. An ordinary glass capillary was utilized as a bio-reactor where competitive assay took place. Standard HA was immobilized onto an unmodified glass capillary through simple physical adsorption. This glass capillary is much lower cost compared to a fused-silica capillary, and is well suited for use as part of the tubing of a flow system. Using the proposed system, the average amount of HA in human serums from patients with liver disease and healthy subjects could be differentiated with comparable efficiency as the conventional micro-plate assay (as compared by t-test), with an improved assay time per sample (20 min vs. 5 h), and with approximately 10 times less reagent consumption (10-80 microl vs. 100-350 microl).

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The purpose of this work was to develop efficient ionochromic polydiacetylenes for lead ion (Pb2+) detection. The method developed used co-assemblies of polydiacetylene and anionic surfactant. The co-assemblies were prepared by mixing 10,12-pentacosadiynoic acid (PCDA) with sodium dodecyl sulphate (SDS) and subsequent UV irradiation-polymerization. The effects of mole ratio of PCDA to SDS, detection limit and stability were investigated. A color transition of poly(PCDA/SDS) co-assemblies with Pb2+ from blue to red was directly observed without the use of any technological equipment. However, Ni2+ and Fe3+ were non-responsive. The co-assemblies of poly(PCDA/SDS) showed rapid ionochromic response and selectivity to Pb2+ in aqueous solution. Based on this approach, the reagent has many advantages such as simple preparation, low cost, low chemical consumption and fast analysis. It is an alternative method for the development if sensing material for the detection of metal ions contaminating the environment.