INTRODUCTION High cell density is known to enhance adipogenic differentiation of mesenchymal stem cells, suggesting secretion of signaling factors or cell-contact-mediated signaling. By employing microfluidic biochip technology, we have been able to separate these two processes and study the secretion pathways. METHODS AND RESULTS Adipogenic differentiation of human adipose-derived stem cells...

Digital microfluidic biochips (DMFB) are rectangular arrays of electrodes, or cells, that enable precise manipulation of nanoliter-sized droplets of biological fluids and chemical reagents. Due to the safety-critical nature of their applications, biochips must be tested frequently, both off-line (e.g., post-manufacturing) and concurrent with assay execution. Under both scenarios, testing is acc...

BACKGROUND AND OBJECTIVES Widespread newborn screening on a point-of-care basis could prevent bilirubin neurotoxicity in newborns with glucose-6-phosphate dehydrogenase (G6PD) deficiency. We evaluated a quantitative G6PD assay on a digital microfluidic platform by comparing its performance with standard clinical methods. METHODS G6PD activity was measured quantitatively by using digital micro...

We introduce the use of immobilized enzymes in hydrogels for proteomic sample processing in digital microfluidic systems. In this technique, pre-formed cylindrical agarose discs bearing immobilized enzymes were integrated into digital microfluidic devices bearing arrays of electrodes. In some experiments, fluorogenic enzyme substrates were delivered to gel discs which served as integrated micro...

Biochips, or digital labs-on-chip, are developed with the purpose of being used by laboratory technicians or biologists in laboratories or clinics. In this article, we expand this vision with the goal of enabling everyone, regardless of their expertise, to use biochips for their own personal purposes. We developed OpenDrop, an integrated electromicrofluidic platform that allows users to develop...

Microfluidic biochips revolutionize biology by placing laboratory functionality on a very small chip. The subject of this thesis is a flow-based biochip, which consists of thin channels in which fluids flow. The basic building block of the chip is a valve, which can direct the flow by blocking or unblocking channels. The valves are combined to create components like switches, mixers, and mul-ti...

Microfluidic technology plays an essential role in various lab on a chip devices due to its desired advantages. An automated microfluidic system integrated with actuators and sensors can further achieve better controllability. A number of microfluidic actuation schemes have been well developed. In contrast, most of the existing sensing methods still heavily rely on optical observations and exte...

A digital microfluidic architecture is introduced for micron-scale localized fluid actuation and in in-situ optical sensing. Contemporary device integration challenges related to localization and device scalability are overcome through the introduction of a bi-layered digital microfluidic multiplexer. Trinary inputs are applied through differential combinations of voltage signals between upper ...

We have developed a biochip platform technology suitable for controlled cell-free gene expression at the micrometer scale. A new hybrid molecule, "Daisy", was designed and synthesized to form in a single step a biocompatible lithographic interface on silicon dioxide. A protocol is described for the immobilization of linear DNA molecules thousands of base pairs long on Daisy-coated surfaces with...

We summarize here the recent progress in fluorescence-based bioassays for the detection and evaluation of food materials by focusing on fluorescent dyes used in bioassays and applications of these assays for food safety, quality and efficacy. Fluorescent dyes have been used in various bioassays, such as biosensing, cell assay, energy transfer-based assay, probing, protein/immunological assay an...