A Sensitive Capacitive Biosensor for Protein a Detection Using Human IgG Immobilized on an Electrode Using Layer-by-Layer Applied Gold Nanoparticles.

A capacitive biosensor for the detection of protein A was developed. Gold electrodes were fabricated by thermal evaporation and patterned by photoresist photolithography. A layer-by-layer (LbL) assembly of thiourea (TU) and HAuCl and chemical reduction was utilized to prepare a probe with a different number of layers of TU and gold nanoparticles (AuNPs).

Alpha-Lipoic Acid Functionalized Silver Nanoparticles for Colorimetric Detection of Copper Ion.

A facile, low cost, rapid and easy-to-use colorimetric sensor for the detection of Cu ion is described using alpha-lipoic acid (ALA) functionalized AgNPs. The prepared ALA-AgNPs are yellow, and spherical with an average particle size of 9.23 ± 3.

Capacitive immunosensor for the detection of host cell proteins.

A new analysis for monitoring host cell proteins in preparations of transgenically produced protein pharmaceuticals is described. A capacitive biosensor with a very high sensitivity is used to monitor trace amounts of host cell proteins. The sensor consists of a gold electrode, the surface of which is well insulated and on which a preparation of a population of polyclonal antibodies raised against the complete protein set-up of the host cell are immobilized.

Ultrasensitive detection of HIV-1 p24 antigen using nanofunctionalized surfaces in a capacitive immunosensor.

The HIV-1 capsid protein, p24 antigen, is of considerable diagnostic interest because following HIV exposure it is detectable several days earlier than host-generated HIV antibodies (which are the target of almost all current tests used in the field) and can be used to design very sensitive assays without the need for PCR. Here, we present an ultrasensitive capacitive immunosensor that is capable of detecting subattogram per milliliter concentrations of p24 antigen, which to our knowledge is the lowest level of detection ever reported. Dilution studies using p24-spiked human plasma samples indicate that the immunosensor is robust against the interfering effects of a complex biological matrix.

Immunochemical binding assays for detection and quantification of trace impurities in biotechnological production.

New, highly sensitive, biosensor concepts make it possible to assay biomacromolecules at concentrations that previously were far below the limit of detection. The previous generation of assays used in quality control situations during biotechnological production was designed primarily for monitoring target molecules, which typically appeared in high concentrations. Hence, novel analytical techniques with high sensitivity should become increasingly important in meeting the demands from regulatory agencies with regard to declaring levels of impurities in biopharmaceuticals.