Theranostic Gelatin Nanoparticles for Antigen Delivery and Combined Strategies for Transcutaneous Application

Abstract

Transcutaneous application of vaccines is a promising strategy to enhance the effectiveness of vaccination using a reachable route of administration. Additionally, replacing the conventional needles with skin mechanical penetration techniques as microneedles or skin laser microporation will offer great advantages. This transcutaneous delivery techniques are pain-free and will help to avoid the hazards of needles. For the delivery of antigens, nanocarriers are so promising to enhance and modulate their immune response. The nanocarriers offer merits such as antigen protection from degradation, and controlling the release rate of the antigen. Additionally, due to the particulate nature of the nanocarriers, they can potentially display the antigen in a way that better mimics pathogens. For this aim, ovalbumin as a model antigen has been delivered using functionalized theranostic gelatin nanoparticles to bone marrow-derived dendritic cells (BMDCs). The nanoparticles were rendered fluorescent by using a novel imaging agent (gold and silver alloy nanoclusters) that emits near-infra red light. This was beneficial to study the nanoparticles uptake by BMDCs and also to image the nanoparticles within the skin tissue. Finally, the developed theranostic nanocarriers induced the maturation of the BMDCs and enhanced the proliferation of both helper T cells (CD4+) and cytotoxic T cells (CD8+). This indicates the potential efficacy of the delivery system for vaccination either against allergy or viruses and tumors.