Improving the sensitivity of immunoassays with PEG-COOH-like film prepared by plasma-based technique.

Herein we report on a preparation and performance of stable, hydrophilic and biocompatible polymeric material suitable for functionalization of disposable substrates used in biosensors. This new material features COOH surface groups cross-linked with ethylene glycol molecules and was prepared in situ on disposable, plastic substrate by high-throughput and environmentally friendly technique called plasma-enhanced chemical vapor deposition (PECVD). The film is grafted to the plasma activated plastic by sequential deposition of tetraethylorthosilicate, forming a bonding layer, and mixed vapors of acrylic acid and diethyleneglycol dimethylether (AA/PEG) that provide the desired functional groups forming a sensing, contact layer.

Nanoparticle-based drug delivery: case studies for cancer and cardiovascular applications.

Nanoparticles (NPs) comprised of nanoengineered complexes are providing new opportunities for enabling targeted delivery of a range of therapeutics and combinations. A range of functionalities can be included within a nanoparticle complex, including surface chemistry that allows attachment of cell-specific ligands for targeted delivery, surface coatings to increase circulation times for enhanced bioavailability, specific materials on the surface or in the nanoparticle core that enable storage of a therapeutic cargo until the target site is reached, and materials sensitive to local or remote actuation cues that allow controlled delivery of therapeutics to the target cells. However, despite the potential benefits of NPs as smart drug delivery and diagnostic systems, much research is still required to evaluate potential toxicity issues related to the chemical properties of NP materials, as well as their size and shape.

Effect of antibody immobilization strategies on the analytical performance of a surface plasmon resonance-based immunoassay.

Antibody immobilization strategies (random, covalent, orientated and combinations of each) were examined to determine their performance in a surface plasmon resonance-based immunoassay using human fetuin A (HFA) as the model antigen system. The random antibody immobilization strategy selected was based on passive adsorption of anti-HFA antibody on 3-aminopropyltriethoxysilane (APTES)-functionalized gold (Au) chips. The covalent strategy employed covalent crosslinking of anti-HFA antibody on APTES-functionalized chips using 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide (EDC) and sulfo-N-hydroxysuccinimide (SNHS).

Novel disposable biochip platform employing supercritical angle fluorescence for enhanced fluorescence collection.

This paper presents an overview of development of a novel disposable plastic biochip for multiplexed clinical diagnostic applications. The disposable biochip is manufactured using a low-cost, rapid turn- around injection moulding process and consists of nine parabolic elements on a planar substrate. The optical elements are based on supercritical angle fluorescence (SAF) which provides substantial enhancement of the fluorescence collection efficiency but also confines the fluorescence detection volume strictly to the immediate proximity of the biochip surface, thereby having the potential to discriminate against background fluorescence from the analyte solution.

Kinetics of immunoassays with particles as labels: effect of antibody coupling using dendrimers as linkers.

In this article, we report on poly(amidoamine) dendrimers (PAMAM) as coupling agents for recombinant single-chain (ScFv) antibodies to nanoparticle (NP) labels, for use in immunoassay. We present a simple theory for the kinetics of particle capture onto a surface by means of an antibody-antigen reaction, in which the important parameter is the fraction of the particle surface that is active for reaction. We describe how increasing the generation number of the linking dendrimers significantly increased the fraction of the NP surface that is active for antigen binding and consequently also increased the assay kinetic rates.