Despite major progress in technologies such as high-throughput screening and computational drug design, poor prediction of drug candidates’ pharmacokinetics has been identified as one of the major causes for high rates of drug clinical failures (Wang & Urban, 2004, pp. 73e86). Currently, in vitro cell cultures and animal models represent the most widely used approaches
adopted to select promising drugs for clinical trials. In particular, conventional cell monolayers are considered the leading models for evaluating the permeation studies of drugs. These flat systems are indeed simple, cost-effective, and standardized tools for replicating some basic biological mechanisms in vitro, such as cito-toxicity, molecule inter/intracellular diffusions. However, 2D cultures cannot precisely reproduce the physiological environment of human
tissues and the physico-chemical structure of the three-dimensional tissues, since the planar 2D surface where cells adhere are oversimplistic in recreating the complex cellecell and cellematrix interaction and also interactions among multiple cell types (Brandon, Raap, Meijerman, Beijnen, & Schellens, 2003; Huh, Hamilton, & Ingber, 2011). Moreover, when they grow on plastic surface, cells are overexposed to chemicals added in the culture medium,
frequently leading to false-positive results for a drug candidate (Kapałczynska et al., 2018; Marrella, 2020; Vitale et al., 2020).
