Abstract: Heterobifunctional crosslinking agents are synthesized that covalently link molecules such as enzymes, cells, proteins and nucleic acids to a plastic substrate. The agents contain a central ring structure having a hydrophobic hydrocarbon chain that binds to a plastic substrate and distal to the hydrophobic chain one or more hydrophilic chains terminating in a reactive group that covalently binds the molecule. Immobilized molecules are useful in diagnostic assays or bioreactors.

Abstract: Heterofunctional crosslinking agents are synthesized that covalently link molecules such as enzymes, cells, proteins and nucleic acids to a plastic substrate. The agents contain a central ring structure having a hydrophobic hydrocarbon chain that binds to a plastic substrate and distal to the hydrophobic chain one or more hydrophilic chains terminating in a reactive group that covalently binds the molecule. Immobilized molecules are useful in diagnostic assays or bioreactors. A preferred heterofunctional crosslinking agent is succinyl-olivetol-N-hydroxysuccinimide having the structure: ##STR1## This agent is prepared by reacting succinic anhydride with 5-pentyl resorcinol and condensing carboxylic acid groups with N-hydroxysuccinimide.

Abstract: A rapid immunoassay device comprising a single porous membrane that serves as both a reagent support and a spent reagent reservoir is disclosed. The immunoassay device directs the flow of sample and reagents within the device in a manner that eliminates both lateral diffusion and backflow of reagents without the necessity of additional external means.

Abstract: A reagent coating material has been developed to modify the surface of articles used in assay procedures. Polymers of chitosan solubilized with an organic acid form into thin films when contacted to glass, plastic, metal or cellulose articles. The coated article may be used directly for immobilizing agents for assay, or may be further modified to increase the range of usefulness. The reagent coating solution itself may also be reacted to produce an activated reagent with surface coating properties. The invention embodies a kit of use in immunoassay procedures.

Abstract: A curl resistant paper-based label. The label includes a coating on the paper layer of the label of a lecithin compound. This compound provides curl resistance properties to the label, water holdout properties to the label and increases the flexibility of the label. A method involves coating the lecithin compounds onto the paper layer of the these labels.