Transdermal drug-delivery systems (TDDS) offer an attractive alternative to the oral route for delivery of biotherapeutics. Technological advancements in the past few decades have revolutionized the fabrication of micro-structured devices including creation of microneedles (MC). These devices are used for delivering peptides, macromolecules such as proteins and DNA, and other therapeutics through the skin. Here, we review the current use of MCs as a cost effective method for the self-administration of therapeutics. We will then review the current and common use of MCs as an effective treatment strategy for a broad range of diseases and their utility in the generation of effective vaccination delivery platforms. Finally, we will summarize the currently FDA approved MCs and their applications, along with the ongoing clinical trials that use such devices.
Parkinson's disease (PD) is a neurodegenerative disorder defined by progressive deterioration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Dental pulp stem cells (DPSCs) have been proposed to replace the degenerated dopaminergic neurons due to its inherent neurogenic and regenerative potential. However, the effective delivery and homing of DPSCs within the lesioned brain has been one of the many obstacles faced in cell-based therapy of neurodegenerative disorders. We hypothesized that DPSCs, delivered intranasally, could circumvent these challenges. In the present study, we investigated the therapeutic efficacy of intranasally administered DPSCs in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. Human deciduous DPSCs were cultured, pre-labelled with PKH 26, and intranasally delivered into PD mice following MPTP treatment. Behavioural analyses were performed to measure olfactory function and sensorimotor coordination, while tyrosine hydroxylase (TH) immunofluorescence was used to evaluate MPTP neurotoxicity in SNpc neurons. Upon intranasal delivery, degenerated TH-positive neurons were ameliorated, while deterioration in behavioural performances was significantly enhanced. Thus, the intranasal approach enriched cell delivery to the brain, optimizing its therapeutic potential through its efficacious delivery and protection against dopaminergic neuron degeneration.