Development of Point-of-Care (POC)
Diagnostic Devices: Biomarker Analysis

We have developed an open-sandwich enzyme-linked immunoadsorbent assay (ELISA) for osteocalcin on a microfluidic chip in collaboration with Dr. Yeoheung Yun of North Carolina A & T State University (NCAT) (Figure 1A). In this assay, the first antibody is covalently attached onto polystyrene beads and manipulated into the microfluidic channel. Osteocalcin is then injected into the microchannel subsequently binding to the first antibody. Fluorescently labeled antibody (monoclonal-Anti BGLAP-Clone 2D5) is then manipulated into the channel forming the sandwich ELISA. Fluorescence proved the existence of osteocalcin binding to the first antibody on polystyrene beads in the microchannel. An alternative assay, employing APTES, has been proven in concept (Figure 1B). Here, osteocalcin is electrostatically attached to the microchannel wall after modifying the surface with APTES. The use of just one fluorescent antibody has qualitatively demonstrated binding of osteocalcin on-a-chip.

Figure 1. (A) Osteocalcin microfluidic ELISA. (B) Alternative osteocalcin assay.


  1. "Human-on-a-Chip Technologies as the Next Generation Drug Screening Platforms," Yun, Y.; Lee, S.; Collins, B.; Gomez, F. A. Sankar, J. J. Nanomedic. Biotherapeu. Discover 2012, 2, 1000e113.
  2. "The Future of Microfluidic Point-of-Care (POC) Diagnostic Devices," Gomez, F. A. Bioanalysis, 2013, 5, 1-3.