Fluorinated Redox-Responsive Poly(amidoamine) as a Vaccine Delivery System for Antitumor Immunotherapy

Targeted therapy of atherosclerosis by pH-sensitive hyaluronic acid nanoparticles co-delivering all-trans retinal and rapamycin

Atherosclerosis, the leading cause of death in the elderly worldwide, is typically characterized by elevated reactive oxygen species (ROS) levels and a chronic inflammatory state at the arterial plaques. Herein, pH-sensitive nanoparticles (HR_RAP NPs) co-delivering all-trans retinal (ATR), an antioxidant linked to hyaluronic acid (HA) through a pH-sensitive hydrazone bond, and rapamycin (RAP), an anti-atherosclerotic drug loaded into the nanoparticle core, are developed for targeted combination therapy of atherosclerosis. In this way, HR_RAP NPs might simultaneously reduce ROS levels via ATR antioxidant activity and reduce inflammation via the anti-inflammatory effect of RAP. In response to mildly acidic conditions mimicking the lesional inflammation in vitro, HR_RAP NPs dissociated and both ATR and RAP were effectively released. The developed HR_RAP NPs effectively inhibited pro-inflammatory macrophage proliferation, and displayed dose- and time-dependent specific internalization by different cellular models of atherosclerosis. Also, HR_RAP NP combination therapy showed an efficient synergetic anti-atherosclerotic effect in vitro by effectively inhibiting the inflammatory response and oxidative stress in inflammatory cells. More importantly, HR NPs specifically accumulated in the atherosclerotic plaques of apolipoprotein E-deficient (ApoE^-/-) mice, by active interaction with HA receptors overexpressed by different cells of the plaque. The treatment with HR_RAP NPs remarkably inhibited the progression of atherosclerosis in ApoE^-/- mice which resulted in stable plaques with considerably smaller necrotic cores, lower matrix metalloproteinase-9, and decreased proliferation of macrophages and smooth muscle cells (SMCs). Furthermore, HR_RAP NPs attenuated RAP adverse effects and exhibited a good safety profile after long-term treatment in mice. Consequently, the developed pH-sensitive HR_RAP NP represent a promising nanoplatform for atherosclerosis combination therapy.

Nanotechnology for Enhanced Cytoplasmic and Organelle Delivery of Bioactive Molecules to Immune Cells

Immune cells stand as a critical component of the immune system to maintain the internal environment homeostasis. The dysfunction of immune cells can result in various life-threatening diseases, including refractory infection, diabetes, cardiovascular disease, and cancer. Therefore, strategies to standardize or even enhance the function of immune cells are critical. Recently, nanotechnology has been highly researched and extensively applied for enhancing the cytoplasmic delivery of bioactive molecules to immune cells, providing efficient approaches to correct in vivo and in vitro dysfunction of immune cells. This review focuses on the technologies and challenges involved in improving endo-lysosomal escape, cytoplasmic release and organelle targeted delivery of different bioactive molecules in immune cells. Furthermore, it will elaborate on the broader vision of applying nanotechnology for treating immune cell-related diseases and constructing immune therapies and cytopharmaceuticals as potential treatments for diseases.

Stimuli-Responsive Nanoparticles for Controlled Drug Delivery in Synergistic Cancer Immunotherapy

Cancer immunotherapy has achieved promising clinical progress over the recent years for its potential to treat metastatic tumors and inhibit their recurrences effectively. However, low patient response rates and dose-limiting toxicity remain as major dilemmas for immunotherapy. Stimuli-responsive nanoparticles (srNPs) combined with immunotherapy offer the possibility to amplify anti-tumor immune responses, where the weak acidity, high concentration of glutathione, overexpressions of enzymes, and reactive oxygen species, and external stimuli in tumors act as triggers for controlled drug release. This review highlights the design of srNPs based on tumor microenvironment and/or external stimuli to combine with different anti-tumor drugs, especially the immunoregulatory agents, which eventually realize synergistic immunotherapy of malignant primary or metastatic tumors and acquire a long-term immune memory to prevent tumor recurrence. The authors hope that this review can provide theoretical guidance for the construction and clinical transformation of smart srNPs for controlled drug delivery in synergistic cancer immunotherapy.

Fluorinate polyacrylic acid and its use as a potential adjuvant field

This study describes a polymer potentially used as a vaccine adjuvant. We first synthesized a novel polyacrylic acid modified by perfluorinated butanol—a bioactive compound that is biocompatible. The main aim was to functionalize the polyacrylic acid by fluorine. This functionalization could offer a permanent graft by an esterification reaction. The chemical structure of the polymer has been characterized by the hydrogen nuclear magnetic resonance spectrum (1H-NMR) and fourier transform infrared spectrum (FT-IR). Thermal analysis showed that the esterification reaction was successful on the polyacrylic acid. Viscosity testing showed that the viscosity of the sample aqueous solution increases along with esterification. The surface tension of the polymer was also tested. The results show that the surface tension of the polyacrylic acid markedly decreased when modified by fluorine. Finally, the interaction of these materials with macrophages was tested on cell test. Results showed that the modified polyacrylic acid performed better improve the activation effect than pure polyacrylic acid in 1L-1β.

Stimuli-Responsive Polymeric Nanomaterials for the Delivery of Immunotherapy Moieties: Antigens, Adjuvants and Agonists

Immunotherapy has been investigated for decades, and it has provided promising results in preclinical studies. The most important issue that hinders researchers from advancing to clinical studies is the delivery system for immunotherapy agents, such as antigens, adjuvants and agonists, and the activation of these agents at the tumour site. Polymers are among the most versatile materials for a variety of treatments and diagnostics, and some polymers are reactive to either endogenous or exogenous stimuli. Utilizing this advantage, researchers have been developing novel and effective polymeric nanomaterials that can deliver immunotherapeutic moieties. In this review, we summarized recent works on stimuli-responsive polymeric nanomaterials that deliver antigens, adjuvants and agonists to tumours for immunotherapy purposes.

Development of Effective Tumor Vaccine Strategies Based on Immune Response Cascade Reactions

To solve the problems of high toxicity and poor efficacy of existing tumor treatment methods, researchers have developed a variety of tumor immunotherapies. Among them, tumor vaccines activate antigen-presenting cells and T lymphocytes upstream of the cancer-immunity cycle are considered the most promising therapy to activate the immune system. Nanocarriers are considered the most promising tumor vaccine delivery vehicles, including polymer nanocarriers, lipid nanocarriers, inorganic nanocarriers, and biomimetic nanocarriers that have been developed for vaccine delivery. Based on the cascade reaction for tumor vaccines to exert their effects, this review summarizes the four key factors for the design and construction of nano-tumor vaccines. The composition and functional characteristics of the corresponding preferred nanocarriers are illustrated to provide a reference for the development of effective tumor vaccines. Finally, potential challenges and perspectives are illustrated in the hope of improving the efficacy of tumor vaccine immunotherapy and accelerating the clinical transformation of next-generation tumor vaccines.

Delivery of nanoparticle antigens to antigen-presenting cells: from extracellular specific targeting to intracellular responsive presentation

An appropriate delivery system can improve the immune effects of antigens against various infections or tumors. Antigen-presenting cells (APCs) are specialized to capture and process antigens in vivo, which link the innate and adaptive immune responses. Functionalization of vaccine delivery systems with targeting moieties to APCs is a promising strategy for provoking potent immune responses. Additionally, the internalization and intracellular distribution of antigens are closely related to the initiation of downstream immune responses. With a deeper understanding of the intracellular microenvironment and the mechanisms of antigen presentation, vehicles designed to respond to endogenous and external stimuli can modulate antigen processing and presentation pathways, which are critical to the types of immune response. Here, an overview of extracellular targeting delivery of antigens to APCs and intracellular stimulus-responsiveness strategies is provided, which might be helpful for the rational design of vaccine delivery systems.

Fluoropolymers in biomedical applications: state-of-the-art and future perspectives

Biomedical applications of fluoropolymers in gene delivery, protein delivery, drug delivery, ¹⁹F MRI, PDT, anti-fouling, anti-bacterial, cell culture, and tissue engineering.

Cationic cross-linked polymers containing labile disulfide and boronic ester linkages for effective triple responsive DNA release

Disruption of DNA carriers triggered by intracellular bio-stimulants has been broadly considered as most convenient strategy for efficient DNA delivery. In this direction, we have designed and synthesized pH, redox and ATP responsive cationic cross-linked polymers (CLPs) having disulfide and reversible boronic ester linkages. These CLPs also contain folate groups that are known for their targeting capability towards cancer cells. Biophysical studies showed that these cationic CLPs exhibited more effective DNA condensation in comparison to cationic linear polymers resulting in the formation of nano-sized polyplexes with sufficient positive zeta potentials and good colloidal stability at neutral pH (∼7.4). More interestingly, the polyplexes prepared from these CLPs have the ability to selectively release complexed DNA under conditions similar to those prevalent in cancer cells such as acidic pH, ATP rich surroundings or presence of glutathione, as revealed by ethidium bromide exclusion assay, agarose gel electrophoresis, AFM measurements, etc. Therefore, these cross-linked polymers have high potential of being effective non-viral gene delivery vehicles.