Development of a spiral-electrode capacitive biosensor for point-of-care diagnosis of leukocytosis and leukopenia

Nguyen Duy Dat, Nguyen Dac Hai

Hanoi University of Industry, Ha Noi, Viet Nam

Keywords: dielectric sensing, cells sensor, spiral-electrode capacitive biosensor, point-of-care diagnosis, leukocyte quantification, gold-labeled CD45+ cells.

Abstract. Monitoring white blood cell counts is essential for diagnosing various medical conditions, including infections and leukemia. This paper proposes a high-sensitivity capacitive sensor featuring spiral-shaped copper electrodes for the detection and quantification of gold-labeled CD45+ cells. The sensor dimensions are 9.99 x 9.99 mm, integrated with a sensing chamber of 0.998 mm³ (9.99 x 9.99 x 0.01 mm). Simulation results demonstrate that the introduction of gold-labeled CD45+ cells alters the local dielectric properties, inducing a measurable shift in capacitance. The proposed device exhibits a near-linear response with a sensitivity of 17.288 fF per gold-labeled CD45+ cell. Given its cost-effectiveness and high precision, this sensor architecture offers a promising solution for point-of-care leukocyte quantification and the early diagnosis of leukocytosis and leukopenia.