A miniaturized photoacoustic device with laptop readout for point-of-care testing of blood glucose.

Photoacoustic (PA) effect has been widely applied in many fields, e.g., physics, chemistry and biomedicine. Herein, a miniaturized PA device is developed by integrating laser source, photo chopper, PA cell, microphone, and laptop for point-of-care testing in bioassay. With glucose assay as model, a piece of paper strip preloading chitosan, starch-potassium iodide (KI) and glucose oxidase (GOD) as lab-on-paper is employed for loading sample prior to PA detection. In the presence of glucose, the product generated on the paper strip would give rise to a strong PA signal in the PA cell under the irradiation of frequency-modulated laser at 520 nm via laptop readout. With a sample volume of 20 μL, a detection limit of 0.03 mM is obtained for glucose assay, along with a linear range of 0.08-1 mM. The accuracy and practicability of the present PA device is well demonstrated by detecting glucose in whole blood. Differing from the conventional PA instrument, the present PA device is really small in bulk with competitive sensitivity and excellent stability, offering a promising tool for point-of-care testing in bioassay.