Novel application of digital microfluidics for the detection of biotinidase deficiency in newborns.

Objective: Newborn screening for biotinidase deficiency can be performed using a fluorometric enzyme assay on dried blood spot specimens. As a pre-requisite to the consolidation of different enzymatic assays onto a single platform, we describe here a novel analytical method for detecting biotinidase deficiency using the same digital microfluidic cartridge that has already been demonstrated to screen for five lysosomal storage diseases (Pompe, Fabry, Gaucher, Hurler and Hunter) in a multiplex format.

Methods: A novel assay to quantify biotinidase concentration in dried blood spots (DBS) was developed and optimized on the digital microfluidic platform using proficiency testing samples from the Centers for Disease Control and Prevention.

Multiplex newborn screening for Pompe, Fabry, Hunter, Gaucher, and Hurler diseases using a digital microfluidic platform.

Purpose: New therapies for lysosomal storage diseases (LSDs) have generated interest in screening newborns for these conditions. We present performance validation data on a digital microfluidic platform that performs multiplex enzymatic assays for Pompe, Fabry, Hunter, Gaucher, and Hurler diseases.

Methods: We developed an investigational disposable digital microfluidic cartridge that uses a single dried blood spot (DBS) punch for performing a 5-plex fluorometric enzymatic assay on up to 44 DBS samples.

Rapid assays for Gaucher and Hurler diseases in dried blood spots using digital microfluidics.

Objective: Easy tool for newborn screening of Gaucher and Hurler diseases.

Methods: Method comparison between fluorometric enzymatic activity assay on a digital microfluidic platform and micro-titer plate bench assay was performed on normal (n = 100), Gaucher (n = 10) and Hurler (n = 7) dried blood spot samples.

Results: Enzymatic activity analysis of glucocerebrosidase (Gaucher) and α-l-iduronidase (Hurler) revealed similar discrimination between normal and affected samples on both platforms.

A novel fluorometric enzyme analysis method for Hunter syndrome using dried blood spots.

Mucopolysaccharidosis type II (MPS II) or Hunter syndrome is a lysosomal storage disease caused by deficiency of iduronate-2-sulfatase (IDS). A convenient single-step fluorometric microplate enzyme assay has been developed and validated for clinical diagnosis of MPS II using dried blood spots (DBS). The assay compared well with a recently reported digital microfluidic method, from which it was adapted.

Digital microfluidic platform for multiplexing enzyme assays: implications for lysosomal storage disease screening in newborns.

Background: Newborn screening for lysosomal storage diseases (LSDs) has been gaining considerable interest owing to the availability of enzyme replacement therapies. We present a digital microfluidic platform to perform rapid, multiplexed enzymatic analysis of acid α-glucosidase (GAA) and acid α-galactosidase to screen for Pompe and Fabry disorders. The results were compared with those obtained using standard fluorometric methods.

Heterogeneous immunoassays using magnetic beads on a digital microfluidic platform.

A digital microfluidic platform for performing heterogeneous sandwich immunoassays based on efficient handling of magnetic beads is presented in this paper. This approach is based on manipulation of discrete droplets of samples and reagents using electrowetting without the need for channels where the droplets are free to move laterally. Droplet-based manipulation of magnetic beads therefore does not suffer from clogging of channels.