POLY(CAPROLACTONE) MICRONEEDLES AS AN INNOVATIVE PLATFORM FOR VACCINE DELIVERY: INDUCTION OF IMMUNE RESPONSES AGAINST KLH-DNP

Vaccination is crucial for disease prevention, but it can cause pain and discomfort, contributing to vaccine hesitancy. Microneedles (MNs) offer a less invasive alternative, enabling direct antigen (Ag) delivery into the skin. MNs made of biocompatible polymers, such as poly(caprolactone) (PCL), provide adequate coverage and dissolve easily after insertion, efficiently releasing Ags. These innovations may improve vaccine acceptance while inducing a strong, lasting immune response. This study evaluates whether KLH-DNP-coated PCL-MNs can act as a vaccine delivery platform and generate antibodies. PCL-MNs were constructed using either 4% alginate or 20% PVA. Rhodamine-loaded PCL-MNs were used to assess release time, monitored by spectrophotometry. BALB/c mice were immunized with KLH-DNP MNs on day 0 and boosted on day 30. Serum samples were collected to analyze anti-DNP IgG titers, and supernatants of cultured spleen cells were collected to analyze cytokine production. PCL-PVA20% MNs showed faster rhodamine release compared to PCL-alginate4%. Anti-DNP IgG levels were detected, significantly increasing after the booster, indicating successful immune activation. Higher IgG1 than IgG2 levels suggested a Th2-mediated humoral response. Increased IFN-gamma and IL-10 production indicated controlled cellular immune activation. PCL-PVA20% MNs show promise as a vaccine platform, successfully delivering KLH-DNP and inducing a favorable immune response.