*2.3.3.1.1.5 Enzyme-linked immunosorbent assays at the point of care*

Ozcan and the group developed a smartphone-based microplate reader for performing enzyme-linked immunosorbent assays at the point of care [102]. The system

**Figure 16.** *Semen analyzer for point-of-care male fertility screening [100].*

#### **Figure 17.**

*Smartphone device with mouthpiece attachment for lung function testing [101].*

#### **Figure 18.**

*Smartphone-based microplate reader for point-of-care enzyme-linked immunosorbent assays [102].*

is composed of a 96-well plate held by a 3D-printed attachment and an LED array for the illumination of the plate. The smartphone camera is mounted on the same attachment, connected with the optical fibers that carry the light to the camera as shown in **Figure 18**. The image taken is sent to online servers for analysis, and the results are sent back to the phone in about 1-minute time. [103] also developed injectable dermal tattoo biosensors for measuring pH, glucose, and albumin concentrations. The biosensors undergo a colorimetric change upon exposure to varying levels of these analytes, such as pH, glucose, and albumin concentrations [103].
