Sensitive quantification of vascular endothelial growth factor (VEGF) using porosity induced hydrogel microspheres

Vascular endothelial growth factor (VEGF) plays a crucial role in vasculogenesis (blood vessel formation) and angiogenesis (capillary formation from a pre-existing blood vessel). Dysregulation of VEGF has been associated with several diseases including cancer, rheumatoid arthritis, and psoriasis. As a result, serum level of VEGF has important implications as biomarker for different clinical disorders as well as for subsequent therapy monitoring. A simple detection method capable of rapid and sensitive analysis of VEGF in serum of patients with different clinical disorders is of paramount importance. Here, we report the fabrication and utilization of capture-antibody immobilized macro-porous poly(ethylene) glycol diacrylate (PEGDA) hydrogel microspheres for quantitative and reproducible measurement of VEGF. We demonstrate that induction of porosity using PEG porogen improves the sensitivity of this simple hydrogel microsphere based system with a detection limit of 2.5pg/ml; indicating that the sensitivity of the assay exceeds that of the conventional technologies. Schematic demonstrating the hydrogel microsphere based VEGF detection system. Initially, capture antibody immobilized microspheres were fabricated in the presence of PEG porogen. Upon incubation in PBS, PEG is removed leaving behind a network of interconnected pores. Increased porosity in turn facilitates enhanced diffusion VEGF and target antibody within the spheres. [Display omitted] •A novel hydrogel microsphere based VEGF detection system.•Induced porosity upon addition of porogen improved sensitivity of the assay.•Utilization of PEG polymer eliminated the need of blocking of proteins as well as reduced the background noise.