Cardiovascular diseases (CVDs) are the leading cause of death globally, taking an estimated 17.9 million lives each year, representing one third of global mortality. As existing therapies still have limited success, due to the inability to control the biodistribution of the currently approved drugs, the quality of life of these patients is modest. The advent of nanomedicine has brought new insights in innovative treatment strategies. For this reason, several novel nanotechnologies have been developed for both targeted and prolonged delivery of therapeutics to the cardiovascular system tο minimize side effects. In this regard, nanoparticles made of natural and/or synthetic nanomaterials, like liposomes, polymers or inorganic materials, are emerging alternatives for the encapsulation of already approved drugs to control their delivery in a targeted way. Therefore, nanomedicine has attracted the attention of the scientific community as a potential platform to deliver therapeutics to the injured heart. In this review, we discuss the current types of biomaterials that have been investigated as potential therapeutic interventions for CVDs as they open up a host of possibilities for more targeted and effective therapies, as well as minimally invasive treatments.
We
present a facile strategy for the synthesis of hybrid nanoparticles
containing gold nanoshells (AuNSs) that absorb at near-infrared (NIR).
Poly(ethylene oxide)-b-poly(l-histidine),
poly(ethylene oxide)-b-poly(
l-histidine)-b-poly(
l-phenylalanine), and poly(ethylene
oxide)-b-poly(
l-histidine)-b-poly(γ-benzyl-l-glutamate) hybrid copolypeptides
were used for the development of AuNSs. Spherical nanoparticles (NPs)
were initially formed by the self-assembly of the amphiphilic hybrid
polypeptides in water. The addition of HAuCl4 followed
by heating, resulted in the reduction of the Au(III) by poly(l-histidine) (PHis), leading to the formation of AuNSs only at the
PHis layer, thus forming a nanoshell within the preformed NPs. The
NPs formed are composed of a poly(ethylene oxide) (PEO) shell, a PHis
layer containing the nanoshell and a poly(l-phenylalanine)
(PPhe) or poly(γ-benzyl-l-glutamate) (PBLG) core. By
controlling the AuNS thickness and the core diameter by the molecular
characteristics of the polymeric precursors as well as the PHis/Au(III)
ratio, the optical properties of the AuNSs can be fine-tuned to absorb
at a specific wavelength. Thus, we achieved a shift of the absorption
peak corresponding to longitudinal surface plasmon resonance to NIR
wavelengths. The size and the morphology of the polymeric NPs containing
AuNSs were examined by TEM and Dynamic Light Scattering. Studies on
a dilute solution of polymeric nanoparticles containing AuNSs showed
that by irradiation with a low power laser at 808 nm, results to significant
increase of its temperature. We present an approach for the design
and facile synthesis of biocompatible polymeric nanoparticles featuring
AuNSs with a peak optical absorption in the NIR that can be fine-tuned.
Therefore, our aim is to present a novel and facile approach for the
formation of AuNSs to be used for photothermal therapy.
Abstract:The highly diverse and sophisticated action of proteins results from their equally diverse primary structure, which along with the nature of interactions between the amino acids, defines the higher self-assembly of proteins. The interactions between amino acids can be very complicated, and their understanding is necessary in order to elucidate the protein structure-properties relationship. A series of well-defined hybrid-polypeptidic diblock copolymers of the type m-PEO-b-poly(His-co-Gly) and m-PEO-b-poly(His-co-Ala) was synthesized through the ring opening polymerization of the N-carboxyanhydrides of the corresponding amino acids, with a molar ratio of the hydrophobic peptide to histidine at 10%, 20% and 40%. The excellent purity of the monomers combined with the high vacuum techniques resulted in controlled polymerization with high molecular and compositional homogeneity. FT-IR, as well as circular dichroism, were employed to investigate the secondary structure of the polymers, while DLS, SLS and ζ-potential were utilized to study the aggregates formed in aqueous solutions, as well as their pH responsiveness. The results revealed that the randomly distributed monomeric units of glycine or alanine significantly influence L-histidine's structure. Depending on the pH, aggregates with a different structure, different molecular characteristics and a different surface charge are formed, potentially leading to very interesting bioapplications.
Abstract:The development of multifunctional polymeric materials for biological applications is mainly guided by the goal of achieving the encapsulation of pharmaceutical compounds through a self-assembly process to form nanoconstructs that control the biodistribution of the active compounds, and therefore minimize systemic side effects. Micelles are formed from amphiphilic polymers in a selective solvent. In biological applications, micelles are formed in water, and their cores are loaded with hydrophobic pharmaceutics, where they are solubilized and are usually delivered through the blood compartment. Even though a large number of polymeric materials that form nanocarrier delivery systems has been investigated, a surprisingly small subset of these technologies has demonstrated potentially curative preclinical results, and fewer have progressed towards commercialization. One of the most promising classes of polymeric materials for drug delivery applications is polypeptides, which combine the properties of the conventional polymers with the 3D structure of natural proteins, i.e., α-helices and β-sheets. In this article, the synthetic pathways followed to develop well-defined polymeric micelles based on polypeptides prepared through ring-opening polymerization (ROP) of N-carboxy anhydrides are reviewed. Among these works, we focus on studies performed on micellar delivery systems to treat cancer. The review is limited to systems presented from 2000-2017.
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