Polymeric hydrogel based systems for vaccine delivery: A review

Synthesis and characterization of poly (β-amino ester) polyplex nanocarrier with high encapsulation and uptake efficiency: impact of extracellular conditions

BACKGROUND

Poly (β-amino Ester) nanocarriers show promise for gene therapy, but their effectiveness can be limited by the environment within the body. This study aims to understand how common cell culture media components affect optimized PBAE nanocarrier performance in gene delivery.

METHODS

Optimized PBAE was synthesized based on Michael addition reaction and characterized by different assays, this study employed techniques like DLS and TEM to characterize PBAE nanocarriers, followed by cellular uptake analysis (flow cytometry and confocal imaging) and evaluation of gene expression under different polymer/DNA ratio ratios and media conditions.

RESULTS

The nanocarriers exhibited size under 200 nm and surface positive charge, with high encapsulation efficiency (up to 95%). Cellular uptake, transfection efficiency, and cytotoxicity were evaluated. Flow cytometry analysis revealed high cellular uptake (over 77% at 1 hour and up to 95% after 3 hours) and good viability. Transfection efficiency reached up to 80% with 2 μg DNA, particularly at weight ratios of 60 and 90.

CONCLUSION

The study also identified factors affecting transfection efficiency, including serum concentration and antibiotics in the culture medium, highlighting the importance of optimizing these conditions for future applications.

Biocompatibility of intraperitoneally implanted TEMPO-oxidized cellulose nanofiber hydrogels for antigen delivery in Atlantic salmon (Salmo salar L.) vaccines

Disease outbreaks are a major impediment to aquaculture production, and vaccines are integral for disease management. Vaccines can be expensive, vary in effectiveness, and come with adjuvant-induced adverse effects, causing fish welfare issues and negative economic impacts. Three-dimensional biopolymer hydrogels are an appealing new technology for vaccine delivery in aquaculture, with the potential for controlled release of multiple immunomodulators and antigens simultaneously, action as local depots, and tunable surface properties. This research examined the intraperitoneal implantation of a cross-linked TEMPO cellulose nanofiber (TOCNF) hydrogel formulated with a Vibrio anguillarum bacterin in Atlantic salmon with macroscopic and microscopic monitoring to 600-degree days post-implantation. Results demonstrated a modified passive integrated transponder tagging (PITT) device allowed for implantation of the hydrogel. However, the Atlantic salmon implanted with TOCNF hydrogels exhibited a significant foreign body response (FBR) compared to sham-injected negative controls. The FBR was characterized by gross and microscopic external and visceral proliferative lesions, granulomas, adhesions, and fibrosis surrounding the hydrogel using Speilberg scoring of the peritoneum and histopathology of the body wall and coelom. Acutely, gross monitoring displayed rapid coagulation of blood in response to the implantation wound with development of fibrinous adhesions surrounding the hydrogel by 72 h post-implantation consistent with early stage FBR. While these results were undesirable for aquaculture vaccines, this work informs on the innate immune response to an implanted biopolymer hydrogel in Atlantic salmon and directs future research using cellulose nanomaterial formulations in Atlantic salmon for a new generation of aquaculture vaccine technology.

Harnessing Nanovaccines for Effective Immunization─A Special Concern on COVID-19: Facts, Fidelity, and Future Prospective

Nanotechnology has emerged as a transformative pathway in vaccine research and delivery. Nanovaccines, encompassing lipid and nonlipid formulations, exhibit considerable advantages over traditional vaccine techniques, including enhanced antigen stability, heightened immunogenicity, targeted distribution, and the potential for codelivery with adjuvants or immune modulators. This review provides a comprehensive overview of the latest advancements and applications of lipid and non-lipid-based nanovaccines in current vaccination strategies for immunization. The review commences by outlining the fundamental concepts underlying lipid and nonlipid nanovaccine design before delving into the diverse components and production processes employed in their development. Subsequently, a comparative analysis of various nanocarriers is presented, elucidating their distinct physicochemical characteristics and impact on the immune response, along with preclinical and clinical studies. The discussion also highlights how nanotechnology enables the possibility of personalized and combined vaccination techniques, facilitating the creation of tailored nanovaccines to meet the individual patient needs. The ethical aspects concerning the use of nanovaccines, as well as potential safety concerns and public perception, are also addressed. The study underscores the gaps and challenges that must be overcome before adopting nanovaccines in clinical practice. This comprehensive analysis offers vital new insights into lipid and nonlipid nanovaccine status. It emphasizes the significance of continuous research, collaboration among interdisciplinary experts, and regulatory measures to fully unlock the potential of nanotechnology in enhancing immunization and ensuring a healthier, more resilient society.

mRNA vaccines and their delivery strategies: A journey from infectious diseases to cancer

mRNA vaccines have evolved as promising cancer therapies. These vaccines can encode tumor-allied antigens, thus enabling personalized treatment approaches. They can also target cancer-specific mutations and overcome immune evasion mechanisms. They manipulate the body's cellular functions to produce antigens, elicit immune responses, and suppress tumors by overcoming limitations associated with specific histocompatibility leukocyte antigen molecules. However, successfully delivering mRNA into target cells destroys a crucial challenge. Viral and nonviral vectors (lipid nanoparticles and cationic liposomes) have shown great capacity in protecting mRNA from deterioration and assisting in cellular uptake. Cell-penetrating peptides, hydrogels, polymer-based nanoparticles, and dendrimers have been investigated to increase the delivery efficacy and immunogenicity of mRNA. This comprehensive review explores the landscape of mRNA vaccines and their delivery platforms for cancer, addressing design considerations, diverse delivery strategies, and recent advancements. Overall, this review contributes to the progress of mRNA vaccines as an innovative strategy for effective cancer treatment.

Immunomodulatory biomaterials against bacterial infections: Progress, challenges, and future perspectives

Bacterial infectious diseases are one of the leading causes of death worldwide. Even with the use of multiple antibiotic treatment strategies, 4.95 million people died from drug-resistant bacterial infections in 2019. By 2050, the number of deaths will reach 10 million annually. The increasing mortality may be partly due to bacterial heterogeneity in the infection microenvironment, such as drug-resistant bacteria, biofilms, persister cells, intracellular bacteria, and small colony variants. In addition, the complexity of the immune microenvironment at different stages of infection makes biomaterials with direct antimicrobial activity unsatisfactory for the long-term treatment of chronic bacterial infections. The increasing mortality may be partly attributed to the biomaterials failing to modulate the active antimicrobial action of immune cells. Therefore, there is an urgent need for effective alternatives to treat bacterial infections. Accordingly, the development of immunomodulatory antimicrobial biomaterials has recently received considerable interest; however, a comprehensive review of their research progress is lacking. In this review, we focus mainly on the research progress and future perspectives of immunomodulatory antimicrobial biomaterials used at different stages of infection. First, we describe the characteristics of the immune microenvironment in the acute and chronic phases of bacterial infections. Then, we highlight the immunomodulatory strategies for antimicrobial biomaterials at different stages of infection and their corresponding advantages and disadvantages. Moreover, we discuss biomaterial-mediated bacterial vaccines' potential applications and challenges for activating innate and adaptive immune memory. This review will serve as a reference for future studies to develop next-generation immunomodulatory biomaterials and accelerate their translation into clinical practice.

Orchestrating Chemical and Physical Cross-Linking in Protein Hydrogels to Regulate Embryonic Stem Cell Growth

Protein hydrogels are ideal candidates for next-generation biomaterials due to their genetically programmable properties. Herein, we report an entirely protein-based hydrogel as an artificial extracellular matrix (ECM) for regulating the embryonic stem cell growth. A synergy between chemical and physical cross-linking was achieved in one step by SpyTag/SpyCatcher reaction and P zipper association at 37 °C. The hydrogels' stress relaxation behaviors can be tuned across a broad spectrum by single-point mutation on a P zipper. It has been found that faster relaxation can promote the growth of HeLa tumor spheroids and embryonic stem cells, and mechanical regulation of embryonic stem cells occurs via retention of the cells at the G1 phase. The results highlight the promise of genetically encoded protein materials as a platform of artificial ECM for understanding and controlling the complex cell-matrix interactions in a 3D cell culture.

Hydrogels as promising platforms for engineered living bacteria-mediated therapeutic systems

The idea of using engineered bacteria as prospective living therapeutic agents for the treatment of different diseases has been raised. Nevertheless, the development of safe and effective treatment strategies remains essential to the success of living bacteria-mediated therapy. Hydrogels have presented great promise for the delivery of living bacterial therapeutics due to their tunable physicochemical properties, good bioactivities, and excellent protection of labile payloads. In this review, we summarize the hydrogel design strategies for living bacteria-mediated therapy and review the recent advances in hydrogel-based living bacterial agent delivery for the treatment of typical diseases, including those for digestive health, skin fungal infections, wound healing, vaccines, and cancer, and discuss the current challenges and future perspectives of these strategies in the field. It is believed that the importance of hydrogel-based living bacteria-mediated therapy is expected to further increase with the development of both synthetic biology and biomaterials science in the future.

Long-Term Vaccine Delivery and Immunological Responses Using Biodegradable Polymer-Based Carriers

Biodegradable polymers are largely employed in the biomedical field, ranging from tissue regeneration to drug/vaccine delivery. The biodegradable polymers are highly biocompatible and possess negligible toxicity. In addition, biomaterial-based vaccines possess adjuvant properties, thereby enhancing immune responses. This Review introduces the use of different biodegradable polymers and their degradation mechanism. Different kinds of vaccines, as well as the interaction between the carriers with the immune system, then are highlighted. Natural and synthetic biodegradable micro-/nanoplatforms, hydrogels, and scaffolds for local or targeted and controlled vaccine release are subsequently discussed.

Polymer-Based Nanosystems-A Versatile Delivery Approach

Polymer-based nanoparticles of tailored size, morphology, and surface properties have attracted increasing attention as carriers for drugs, biomolecules, and genes. By protecting the payload from degradation and maintaining sustained and controlled release of the drug, polymeric nanoparticles can reduce drug clearance, increase their cargo's stability and solubility, prolong its half-life, and ensure optimal concentration at the target site. The inherent immunomodulatory properties of specific polymer nanoparticles, coupled with their drug encapsulation ability, have raised particular interest in vaccine delivery. This paper aims to review current and emerging drug delivery applications of both branched and linear, natural, and synthetic polymer nanostructures, focusing on their role in vaccine development.