Embodiments of the invention are directed to a sensor that includes a sensing circuit and a probe communicatively coupled to the sensing circuit. The probe includes a three-dimensional (3D) sensing surface coated with a recognition element and configured to, based at least in part on the 3D sensing surface interacting with a predetermined material, generate a first measurement. In some embodiments, the 3D sensing surface is shaped as a pyramid, a cone, or a cylinder to increase the sensing surface area over a two-dimensional (2D) sensing surface. In some embodiments, the 3D sensing surface facilitates penetration of the 3D sensing surface through the wall of the biological cell.