Poly-glutamic dendrimer-based conjugates for cancer vaccination - a computational design for targeted delivery of antigens

Peptide Dendrimer-Based Antibacterial Agents: Synthesis and Applications

Pathogenic bacteria cause the deaths of millions of people every year. With the development of antibiotics, hundreds and thousands of people's lives have been saved. Nevertheless, bacteria can develop resistance to antibiotics, rendering them insensitive to antibiotics over time. Peptides containing specific amino acids can be used as antibacterial agents; however, they can be easily degraded by proteases in vivo. To address these issues, branched peptide dendrimers are now being considered as good antibacterial agents due to their high efficacy, resistance to protease degradation, and low cytotoxicity. The ease with which peptide dendrimers can be synthesized and modified makes them accessible for use in various biological and nonbiological fields. That is, peptide dendrimers hold a promising future as antibacterial agents with prolonged efficacy without bacterial resistance development. Their in vivo stability and multivalence allow them to effectively target multi-drug-resistant strains and prevent biofilm formation. Thus, it is interesting to have an overview of the development and applications of peptide dendrimers in antibacterial research, including the possibility of employing machine learning approaches for the design of AMPs and dendrimers. This review summarizes the synthesis and applications of peptide dendrimers as antibacterial agents. The challenges and perspectives of using peptide dendrimers as the antibacterial agents are also discussed.

Computer simulation of the structural properties of fatty-acid modified PAMAM dendrimers at pH 5 and 7

In this work, we performed coarse-grained molecular dynamics (CGMD) simulations of G3, G4, and G5 polyamidoamine (PAMAM) dendrimers grafting with fatty acid (FTA) chains. The FTA chains of varying length and grafting densities (50% and 100% of surface terminals) correspond to pH 7 and 5, respectively. Our findings suggested that the structural properties of dendrimers were determined by dendrimer generation, polymerization degrees, and pH. With one exception, the size of the FTA grafting dendrimer shrank after fatty acid attachment. Because of the protonation of the dendrimer's interior amines at low pH, the FTA chains are distributed at the dendrimer's surface group. At pH 7, the FTA chains that have aggregated in the interior of the dendrimer cause chain crowding. Our research provided references on drug encapsulation and the lower toxicity of these hydrophobically modified nanoparticles.

Dendrimers in vaccine delivery: Recent progress and advances

Dendrimers are well-defined, highly branched, multivalent and monodisperse molecules which host a range of attractive, yet functional, chemical and biological characteristics. A dendrimers accessible surface groups enable coupling to different functional moieties (e.g., antibodies, peptides, proteins, etc), which is further assisted by the dendrimers tailored size and surface charge. This adaptability allows for the preparation of molecularly precise vaccines with highly specific and predictable properties, and in conjunction with a dendrimers immune stimulating (adjuvanting) property, makes dendrimers attractive substrates for biomedical applications, including vaccines. This review highlights the structural and synthetic evolution of dendrimers throughout history, detailing the dendrimers role as both an adjuvant and carrier system for vaccine antigens, in addition to reviewing the development of commercially available vaccines for use in humans.

An update on the use of molecular modeling in dendrimers design for biomedical applications: are we using its full potential?

INTRODUCTION

Dendrimers are well-defined hyperbranched polymers built from a variety of different monomers and with tuneable properties that make them suitable for different biomedical applications. Their three-dimensional (3D) structure cannot be usually determined experimentally due to their inherent nature of repeating patterns in the topology, failure to crystalize, and/or high flexibility. Therefore, their conformations and interactions at the atomistic level can be studied only by using computational chemistry methods, including molecular dynamics, Monte Carlo simulations, and molecular docking.

AREAS COVERED

In this review, the methods that could be utilized in computer-aided dendrimer design are considered, providing a list of approaches to generate initial 3D coordinates and selected examples of applications of relevant molecular modeling methods.

EXPERT OPINION

Computational chemistry provides an invaluable set of tools to study dendrimers and their interactions with drugs and biological targets. There is a gap in the software development that is dedicated to study of these highly variable and complex systems that could be overcome by the integration of already established approaches for topology generation and open source molecular modeling libraries. Furthermore, it would be highly beneficial to collate already built 3D models of various dendrimers with corresponding relevant experimental data.

Therapeutic potential of polypeptide-based conjugates: Rational design and analytical tools that can boost clinical translation

The clinical success of polypeptides as polymeric drugs, covered by the umbrella term "polymer therapeutics," combined with related scientific and technological breakthroughs, explain their exponential growth in the development of polypeptide-drug conjugates as therapeutic agents. A deeper understanding of the biology at relevant pathological sites and the critical biological barriers faced, combined with advances regarding controlled polymerization techniques, material bioresponsiveness, analytical methods, and scale up-manufacture processes, have fostered the development of these nature-mimicking entities. Now, engineered polypeptides have the potential to combat current challenges in the advanced drug delivery field. In this review, we will discuss examples of polypeptide-drug conjugates as single or combination therapies in both preclinical and clinical studies as therapeutics and molecular imaging tools. Importantly, we will critically discuss relevant examples to highlight those parameters relevant to their rational design, such as linking chemistry, the analytical strategies employed, and their physicochemical and biological characterization, that will foster their rapid clinical translation.

Topological Aspects of the Design of Nanocarriers for Therapeutic Peptides and Proteins

Supramolecular chemistry holds great potential for the design of versatile and safe carriers for therapeutic proteins and peptides. Nanocarriers can be designed to meet specific criteria for given application (exact drug, administration route, target tissue, etc.). However, alterations in the topology of formulation components can drastically change their activity. This is why the supramolecular topology of therapeutic nanoconstructions has to be considered. Herein, we discuss several topological groups used for the design of nanoformulations for peptide and protein delivery: modification of polypeptide chains by host-guest interactions; packaging of proteins and peptides into liposomes; complexation and conjugation with dendrimers. Each topological type has its own advantages and disadvantages, so careful design of nanoformulations is needed. Ideally, each case where nanomedicine is needed requires a therapeutic construction specially created for that taking into account features of the administration route, target tissue, or organ, properties of a drug, its bioavailability, etc. The wide number of studies in the field of protein delivery by supramolecular and nanocarriers for proteins and peptides evidence their increasing potential for different aspects of the innovative medicine. Although significant progress has been achieved in the field, there are several remaining challenges to be overcome in future.

Nanotechnology Approaches to Improving Cancer Immunotherapy

Cancer immunotherapy is a powerful, growing treatment approach to cancer that can be combined with chemotherapy, radiotherapy, and oncosurgery. Modulating the immune system to enhance anticancer response by several strategies has yielded improved cancer survival. Despite this progress, the success rate for immunotherapy has been below expectations due to unpredictable efficacy and off-target side effects from systemic dosing. Nanotechnology offers numerous different materials and targeting properties to overcome many of these challenges in immunotherapy. In this chapter, we review current immunotherapy and its challenges as well as the latest nanotechnology applications in cancer immunotherapy.