Joel N. Maslow

We evaluated the safety and immunogenicity of boost vaccination with the GLS-5310 SARS-CoV-2 DNA vaccine to those previously vaccinated with the Ad26.S.CoV2, BNT162b2, or mRNA-1273 vaccines. GLS-5310 was administered intradermally (ID) and followed by application of suction using the GeneDerm device, or ID as well as intranasally (IN) by nasal atomizer. GLS-5310 vaccination was well tolerated. With respect to primary vaccine type, boost vaccination induced a 1.5- to 4-fold increase in antibody titers, up to a 14.4-fold increase in T cell responses by ELISpot. Incident SARS-CoV-2 infections, during a period of Omicron prevalence, were reported for 24.2% of participants: 1 of 17 (5.9%) vaccinated ID plus IN versus 16 of 53 (30.2%) vaccinated ID only, p = 0.042 (chi-square analysis). This first ever trial of a DNA vaccine administered IN plus ID showed potential protection against incident SARS-CoV-2 Omicron infection. NCT Clinical Trial number: NCT05182567

Microneedle arrays have been shown to be a minimally invasive method of transdermal drug delivery. However, methods to coat these arrays often require a reservoir of the active ingredient, leading to material unused and wasted. Electrospray deposition is a targeted coating method that offers a competitive alternative for coating microneedles. By architecting the charge landscape of the setup, this technology can achieve coating deposition efficiencies nearing 100%, with little to no material wasted during the coating process. A Middle East respiratory syndrome coronavirus DNA vaccine was used as the model material to assess deposition efficiency as well as the efficacy of fragile biological materials subjected to electrospray deposition. These coatings were inserted into Sprague Dawley rats where the antigen was subsequently detected and located using immunohistochemistry. This work demonstrates the capability of electrospray deposition as a highly efficient method to coat microneedles for transdermal drug delivery.

Cutaneous suction‐based transfection is a recently developed technique that is painless and simple‐to‐use for the delivery of DNA for nucleic‐acid‐based vaccines. The technique promises high efficiency for both antigen expression and immunogenicity as demonstrated in both animal studies and human clinical trials. To realize this promise, a parametric study and systematic evaluation of the efficacy of cutaneous suction as a transfection method is performed. Using Green Fluorescent Protein (GFP) plasmid expression as a transfection reporter in a rat model, the expression level as a function of both suction nozzle size and suction pressure is quantified. A numerical model is employed to compute skin deformation in terms of strain, which is used to correlate with GFP expression. Based on these results, two quantities, integrated total strain and tissue tension, are proposed as indicators of expression level that can be used to guide protocol development and optimization. These indicators are also discussed in relation to possible cellular uptake mechanisms.

Cutaneous suction-based transfection is a recently developed technique that is painless and simple-to-use for the delivery of DNA for nucleic-acid-based vaccines. The technique promises high efficiency for both antigen expression and immunogenicity as demonstrated in both animal studies and human clinical trials. To realize this promise, a parametric study and systematic evaluation on the efficacy of cutaneous suction as a transfection method was performed. Using Green Fluorescent Protein (GFP) plasmid expression as a transfection reporter in a rat model, the expression level as a function of both suction nozzle size and suction pressure was quantified. A numerical model was employed to compute skin deformation in terms of strain, which was used to correlate with GFP expression. Based on these results, two quantities, total integrated strain and tissue tension, are proposed as indicators of expression level that can be used to guide protocol development and optimization. These indicators are also discussed in relation to possible cellular uptake mechanisms.

Electrospray deposition (ESD) is a promising technique for depositing micro-/nano-scale droplets and particles with high quality and repeatability. It is particularly attractive for surface coating of costly and delicate biomaterials and bioactive compounds. While high efficiency of ESD has only been successfully demonstrated for spraying surfaces larger than the spray plume, this work extends its utility to smaller surfaces. It is shown that by architecting the local “charge landscape”, ESD coatings of surfaces smaller than plume size can be achieved. Efficiency approaching 100% is demonstrated with multiple model materials, including biocompatible polymers, proteins, and bioactive small molecules, on both flat and microneedle array targets. UV-visible spectroscopy and high-performance liquid chromatography measurements validate the high efficiency and quality of the sprayed material. Here, we show how this process is an efficient and more competitive alternative to other conformal coating mechanisms, such as dip coating or inkjet printing, for micro-engineered applications.

We highlight the significant progress in developing DNA vaccines during the SARS-CoV-2 pandemic. Specifically, we provide a comprehensive review of the DNA vaccines that have progressed to Phase 2 testing or beyond, including those that have received authorization for use. DNA vaccines have significant advantages with regard to the rapidity of production, thermostability, safety profile, and cellular immune responses. Based on user needs and cost, we compare the three devices used in the SARS-CoV-2 clinical trials. Of the three devices, the GeneDerm suction device offers numerous benefits, particularly for international vaccination campaigns. As such, DNA vaccines represent a promising option for future pandemics.

Intradermal (ID) injection is a technique widely used in laboratorial and clinical applications. The boundary of the dome-like bleb formed during injection is assumed to represent the lateral extent of the injected material. This work systematically characterizes cargo molecule distribution (puddle) as a function of injection volume and molecular/particle size in rat skin post ID injection. In general, results indicate that the puddle forms a subdomain laterally contained within the bleb, with an area inversely correlating to the molecular size of the injected material. For 50 μL and 100 µL injections, the average area of the bleb was 40.97 ± 6.30 mm² and 55.64 ± 8.20 mm², respectively, regardless of the molecular/particle size. On the other hand, the area of the puddle was dependent on the molecular size and ranged between 45.38 ± 8.29 mm² and 6.14 ± 4.50 mm² for 50 µL injections, and 66.64 ± 11.22 mm² and 11.50 ± 9.67 mm² for 100 µL injections. The lateral distribution appears to have no time-dependency up to 10 min post injection. The trend in the depth of cargo penetration is also similar, with smaller particles extending deeper into the dermis and subcutaneous fat layers. Because the area of puddle can be significantly less than that of the bleb, establishing base characterization is essential to understand cellular interactions with the injected biological substances.

In the present study, the effect(s) of the immunomodulatory drug GLS-1027 on various cell types involved in inflammation were investigated. GLS-1027 reduced LPS-stimulated secretion of pro-inflammatory cytokines by macrophage or monocytic cells and cell lines. This reduction was likely due in part to decreased activation of NF-κB family transcription factors and inhibition of p38 MAPK signaling in GLS-1027-treated cells. Independent from its effects on macrophages, GLS-1027 inhibited dendritic cell maturation and differentiation of naïve CD4⁺ T cells into Th17 cells, reducing the production of typical pro-inflammatory cytokines associated with both processes. In vivo administration of GLS-1027 prevented the development of type 1 diabetes in NOD mice which correlated with reduced serum levels of IL17A in GLS-1027 treated animals and reduced ex vivo production of IL17A from both spleen and lymph-node cells. Overall, our data show that GLS-1027 can reduce inflammation through multiple actions, including the reduction of pro-inflammatory cytokine production by innate immune cells, the inhibition of dendritic cells maturation, and the inhibition of Th17 cells polarization.