Microneedle-mediated vaccine delivery

Conventional vaccines are administered intramuscularly or subcutaneously via hypodermic needles, causing pain and stress. Since the skin is a powerful immune organ, it is not surprising that intradermal injections result in potent immune responses. However, they are relatively difficult to perform and very painful. Advances in microfabrication techniques make microneedle-based dermal vaccination a viable alternative to traditional injections. Microneedles are micron-sized structures with a length of less than 1 mm that are used to deliver drugs, including vaccines, into the skin. The minimally-invasive, potentially pain free nature and ease of drug delivery can reduce the risk of infections and alleviate the need for trained personnel. This thesis describes several fundamental parameters that influence skin penetration by microneedles as well as factors that affect antigen-specific immune responses in animals following microneedle-based vaccination. Besides, the importance of using a microneedle insertion device for self-administration of microneedles is highlighted. Moreover, ultrathin pH-sensitive surface modifications for microneedles were developed to improve the coating of antigens and the efficiency of microneedle-mediated vaccine delivery. Finally, a method was developed to fabricate hollow microneedles, which were successfully used for polio vaccination. In conclusion, these studies provide important new insights for enabling pain free vaccination via the skin.UBL - phd migration 201

Cationic nanoparticle-based cancer vaccines

Cationic nanoparticles have been shown to be surprisingly effective as cancer vaccine vehicles in preclinical and clinical studies. Cationic nanoparticles deliver tumor-associated antigens to dendritic cells and induce immune activation, resulting in strong antigen-specific cellular immune responses, as shown for a wide variety of vaccine candidates. In this review, we discuss the relation between the cationic nature of nanoparticles and the efficacy of cancer immunotherapy. Multiple types of lipid- and polymer-based cationic nanoparticulate cancer vaccines with various antigen types (e.g., mRNA, DNA, peptides and proteins) and adjuvants are described. Furthermore, we focus on the types of cationic nanoparticles used for T-cell induction, especially in the context of therapeutic cancer vaccination. We discuss different cationic nanoparticulate vaccines, molecular mechanisms of adjuvanticity and biodistribution profiles upon administration via different routes. Finally, we discuss the perspectives of cationic nanoparticulate vaccines for improving immunotherapy of cancer.Tumorimmunolog

Advanced micro and nano manufacturing technologies used in medical domain

This paper focuses on the aspects of advanced manufacturing technologies, namely micro and nano manufacturing (MNM) capabilities which are particularly relevant to medical domain. In recent years, the so called disruptive technologies have enabled engineers and clinicians to collaborate in solving complex problems which require advanced MNM capabilities to develop medical applications. As a result what was nearly impossible a few years ago, due to limitations in machining and manufacturability of micro and nano scale artefacts, are now made possible thanks to innovative manufacturing processes and technologies. The potential medical applications of the new MNM methods are immense and in this paper four potential uses, namely as medical devices, lab on chips, and brain implants are presented and discussed. These works were based on different projects undertaken by researchers at Cardiff University, UK. The manufacturing costs, though initially high, are expected to reduce over time as the technologies mature and become more widely available. Introducing these MNM technologies and disseminating these results to healthcare engineering, for a better quality of medical diagnosis and treatments with cost-effective solutions, will greatly benefit the majority of population who live in the developing countries in receiving appropriate and affordable medical care to achieve improvements in their quality of life

Quantification of lipid and peptide content in antigenic peptide-loaded liposome formulations by reversed-phase UPLC using UV absorbance and evaporative light scattering detection

Antigenic peptide-loaded cationic liposomes have shown promise as cancer vaccines. Quantification of both peptides and lipids is critical for quality control of such vaccines for clinical translation. In this work we describe a reversed phase ultra-performance liquid chromatography (RP-UPLC) method that separates lipids (DOTAP, DOPC and their degradation products) and two physicochemically different peptides within 12 min. Samples were prepared by dilution in a 1:1 (v/v) mixture of methanol and water. Peptide quantifi-cation was done via UV detection and lipids were quantified by an evaporative light scattering detector (ELSD), both coupled to the RP-UPLC system, with high precision (RSD < 3.5%). We showed that the presence of lipids and peptides did not mutually influence their quantification. Limit of detection (LOD) and limit of quantification (LOQ), as determined in the ICH guidelines, were 6 and 20 ng for DOTAP, 12 ng and 40 ng for DOPC, 3.0 ng and 8.0 ng for peptide A and 2.4 ng and 7.2 ng for the more hydrophobic peptide B. Finally, lipid degradation of DOTAP and DOPC was monitored in peptide loaded DOTAP:DOPC liposomes upon storage at 4 degrees C and 40 degrees C.(c) 2022 The Authors. Published by Elsevier Inc. on behalf of American Pharmacists Association. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)Drug Delivery Technolog

Rapid, low cost prototyping of transdermal devices for personal healthcare monitoring

The next generation of devices for personal healthcare monitoring will comprise molecular sensors to monitor analytes of interest in the skin compartment. Transdermal devices based on microneedles offer an excellent opportunity to explore the dynamics of molecular markers in the interstitial fluid, however good acceptability of these next generation devices will require several technical problems associated with current commercially available wearable sensors to be overcome. These particularly include reliability, comfort and cost. An essential pre-requisite for transdermal molecular sensing devices is that they can be fabricated using scalable technologies which are cost effective.We present here a minimally invasive microneedle array as a continuous monitoring platform technology. Method for scalable fabrication of these structures is presented. The microneedle arrays were characterised mechanically and were shown to penetrate human skin under moderate thumb pressure. They were then functionalised and evaluated as glucose, lactate and theophylline biosensors. The results suggest that this technology can be employed in the measurement of metabolites, therapeutic drugs and biomarkers and could have an important role to play in the management of chronic diseases

Prednisolone-induced differential gene expression in mouse liver carrying wild type or a dimerization-defective glucocorticoid receptor

Contains fulltext : 89658.pdf (publisher's version ) (Open Access)BACKGROUND: Glucocorticoids (GCs) control expression of a large number of genes via binding to the GC receptor (GR). Transcription may be regulated either by binding of the GR dimer to DNA regulatory elements or by protein-protein interactions of GR monomers with other transcription factors. Although the type of regulation for a number of individual target genes is known, the relative contribution of both mechanisms to the regulation of the entire transcriptional program remains elusive. To study the importance of GR dimerization in the regulation of gene expression, we performed gene expression profiling of livers of prednisolone-treated wild type (WT) and mice that have lost the ability to form GR dimers (GRdim). RESULTS: The GR target genes identified in WT mice were predominantly related to glucose metabolism, the cell cycle, apoptosis and inflammation. In GRdim mice, the level of prednisolone-induced gene expression was significantly reduced compared to WT, but not completely absent. Interestingly, for a set of genes, involved in cell cycle and apoptosis processes and strongly related to Foxo3a and p53, induction by prednisolone was completely abolished in GRdim mice. In contrast, glucose metabolism-related genes were still modestly upregulated in GRdim mice upon prednisolone treatment. Finally, we identified several novel GC-inducible genes from which Fam107a, a putative histone acetyltransferase complex interacting protein, was most strongly dependent on GR dimerization. CONCLUSIONS: This study on prednisolone-induced effects in livers of WT and GRdim mice identified a number of interesting candidate genes and pathways regulated by GR dimers and sheds new light onto the complex transcriptional regulation of liver function by GCs

Diphtheria toxoid and N-trimethyl chitosan layer-by-layer coated pH-sensitive microneedles induce potent immune responses upon dermal vaccination in mice

Dermal immunization using antigen-coated microneedle arrays is a promising vaccination strategy. However, reduction of microneedle sharpness and the available surface area for antigen coating is a limiting factor. To overcome these obstacles, a layer-by-layer coating approach can be applied onto pH-sensitive microneedles. Following this approach, pH-sensitive microneedle arrays (positively charged at coating pH 5.8 and nearly uncharged at pH 7.4) were alternatingly coated with negatively charged diphtheria toxoid (DT) and N-trimethyl chitosan (TMC), a cationic adjuvant. First, the optimal DT dose for intradermal immunization was determined in a dose-response study, which revealed that low-dose intradermal immunization was more efficient than subcutaneous immunization and that the EC50 dose of DT upon intradermal immunization is 3-fold lower, as compared to subcutaneous immunization. In a subsequent immunization study, microneedle arrays coated with an increasing number (2, 5, and 10) of DT/TMC bilayers resulted in step-wise increasing DT-specific immune responses. Dermal immunization with microneedle arrays coated with 10 bilayers of DT/TMC (corresponding with ± 0.6 μg DT delivered intradermally) resulted in similar DT-specific immune responses as subcutaneous immunization with 5 μg of DT adjuvanted with aluminum phosphate (8-fold dose reduction). Summarizing, the layer-by-layer coating approach onto pH-sensitive microneedles is a versatile method to precisely control the amount of coated and dermally-delivered antigen that is highly suitable for dermal immunization.Drug Delivery Technolog