Functional multilayered polymeric nanocarriers for delivery of mitochondrial targeted anticancer drug curcumin

Cinnamyl-Modified Polyglycidol/Poly(ε-Caprolactone) Block Copolymer Nanocarriers for Enhanced Encapsulation and Prolonged Release of Cannabidiol

The present study describes the development of novel block copolymer nanocarriers of the phytocannabinoid cannabidiol (CBD), designed to enhance the solubility of the drug in water while achieving high encapsulation efficiency and prolonged drug release. Firstly, a well-defined amphiphilic block copolymer consisting of two outer hydrophilic polyglycidol (PG) blocks and a middle hydrophobic block of poly(ε-caprolactone) bearing pendant cinnamyl moieties (P(CyCL-co-CL)) were synthesized by the click coupling reaction of PG-monoalkyne and P(CyCL-co-CL)-diazide functional macroreagents. A non-modified polyglycidol/poly(ε-caprolactone) amphiphilic block copolymer was obtained as a referent system. Micellar carriers based on the two block copolymers were formed via the solvent evaporation method and loaded with CBD following two different protocols-loading during micelle formation and loading into preformed micelles. The key parameters/characteristics of blank and CBD-loaded micelles such as size, size distribution, zeta potential, molar mass, critical micelle concentration, morphology, and encapsulation efficiency were determined by using dynamic and static multiangle and electrophoretic light scattering, transmission electron microscopy, and atomic force microscopy. Embedding CBD into the micellar carriers affected their hydrodynamic radii to some extent, while the spherical morphology of particles was not changed. The nanoformulation based on the copolymer bearing cinnamyl moieties possessed significantly higher encapsulation efficiency and a slower rate of drug release than the non-modified copolymer. The comparative assessment of the antiproliferative effect of micellar CBD vs. the free drug against the acute myeloid leukemia-derived HL-60 cell line and Sezary Syndrome HUT-78 demonstrated that the newly developed systems have pronounced antitumor activity.

Recent Advances on PEO-PCL Block and Graft Copolymers as Nanocarriers for Drug Delivery Applications

Poly(ethylene oxide)-poly(ε-caprolactone) (PEO-PCL) is a family of block (or graft) copolymers with several biomedical applications. These types of copolymers are well-known for their good biocompatibility and biodegradability properties, being ideal for biomedical applications and for the formation of a variety of nanosystems intended for controlled drug release. The aim of this review is to present the applications and the properties of different nanocarriers derived from PEO-PCL block and graft copolymers. Micelles, polymeric nanoparticles, drug conjugates, nanocapsules, and hybrid polymer-lipid nanoparticles, such as hybrid liposomes, are the main categories of PEO-PCL based nanocarriers loaded with different active ingredients. The advantages and the limitations in preclinical studies are also discussed in depth. PEO-PCL based nanocarriers could be the next generation of delivery systems with fast clinical translation. Finally, current challenges and future perspectives of the PEO-PCL based nanocarriers are highlighted.

Nanotechnology - a robust tool for fighting the challenges of drug resistance in non-small cell lung cancer

Genomic and proteomic mutation analysis is the standard of care for selecting candidates for therapies with tyrosine kinase inhibitors against the human epidermal growth factor receptor (EGFR TKI therapies) and further monitoring cancer treatment efficacy and cancer development. Acquired resistance due to various genetic aberrations is an unavoidable problem during EGFR TKI therapy, leading to the rapid exhaustion of standard molecularly targeted therapeutic options against mutant variants. Attacking multiple molecular targets within one or several signaling pathways by co-delivery of multiple agents is a viable strategy for overcoming and preventing resistance to EGFR TKIs. However, because of the difference in pharmacokinetics among agents, combined therapies may not effectively reach their targets. The obstacles regarding the simultaneous co-delivery of therapeutic agents at the site of action can be overcome using nanomedicine as a platform and nanotools as delivery agents. Precision oncology research to identify targetable biomarkers and optimize tumor homing agents, hand in hand with designing multifunctional and multistage nanocarriers that respond to the inherent heterogeneity of the tumors, may resolve the challenges of inadequate tumor localization, improve intracellular internalization, and bring advantages over conventional nanocarriers.

Triblock Copolymer Micelles with Tunable Surface Charge as Drug Nanocarriers: Synthesis and Physico-Chemical Characterization

Polymeric micelles have gained increasing interest as efficient drug delivery systems for cancer treatment and diagnosis. The aim of the present study was to construct and to evaluate novel polymeric nanosized drug carriers with tunable surface charges. Initially, amphiphilic triblock copolymers with predetermined molar mass characteristics were synthesized by applying controlled polymerization techniques. The copolymers self-assembled in aqueous media into core–shell spherical micelles, comprising a biodegradable hydrophobic poly(D,L-lactide) core, positively charged middle layer of poly((2-dimethylamino)ethyl methacrylate), and an outer shell of neutral hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate), with various densities of the short polyether side chains. The block copolymer micelles with average diameters of about 70 nm and surface charges varying from strongly positive to neutral were characterized and loaded with the model, natural, hydrophobic drug curcumin. Characteristics such as drug loading efficiency, in-vitro drug release profiles, and stability under physiological conditions were evaluated and discussed in terms of nanocarriers’ composition. As a result, the most promising candidates for potential application in nanomedicine were identified.

Understanding release kinetics and collapse proof suture retention response of curcumin loaded electrospun mats based on aliphatic polyesters and their blends

The paper aims at designing and fabrication of PLA/PCL blended suture resistant electrospun mats (EMs) encapsulating non-toxic curcumin and optimization of its release behavior, to facilitate its sustained release at the targeted areas, without complexation with any chemical and/or synthetic drug. The release of curcumin from PLA/PCL blended EMs followed a diffusion-controlled mechanism, as evident from the agreement of the experimental release data with Peppas- Korsmeyer, Higuchi, and Kopcha model. The curcumin embedded EMs have effectively rendered a release confirming to a new generalized logarithmic model. PLA/PCL blended EMs have proved to be an excellent carrier system, exhibiting enhanced cumulative curcumin release with an increase in curcumin loading. The evaluation of structural and viscoelastic properties of the fabricated EMs showed an increase in modulus and strength, along with a subsequent decrease in elongation, with an increase in curcumin content. Suture-induced cooperative collapse dynamics the EMs have been found to be a three-stage process involving stable, stable-unstable, and fast-unstable structural failure corresponding to network realignment, lateral pullout/fracture of fibers, and divergent tearing along the crack path. The viscoelastic responses showed a prominent shift in glass transition temperature (T_g) of the PCL phase indicating the development of curcumin-induced microstructural changes attributed to the H-bonding interaction with polymer segments of PLA/PCL-based EMs. Our study demonstrates, functionally efficient designing of PLA/PCL-based curcumin-loaded biodegradable EMs with sustained retention of tunable mechanical properties and hydrophobicity, irrespective of the extent of (in-vitro) curcumin release.

Superior proapoptotic activity of curcumin-loaded mixed block copolymer micelles with mitochondrial targeting properties

Targeting tumor cell mitochondria is a prospective strategy for highly effective anticancer therapy. Consequently, the development of potent systems for the targeted delivery of mitochondria-acting therapeutics to mitochondria has the potential to boost this sector of nanomedicine. In this study, a functional mixed micellar system based on two co-assembled triblock copolymers, poly(2-(dimethylamino)ethyl methacrylate)-b-poly(ε-caprolactone)-b-poly(2-(dimethylamino)ethyl methacrylate) bearing triphenylphosphonium ligands (PDMAEMA(TPP+)20-b-PCL70-b-PDMAEMA(TPP+)20) and poly(ethylene oxide)-b-poly(ε-caprolactone)-b-poly(ethylene oxide) (PEO113-b-PCL70-b-PEO113), was assessed for the mitochondria targeted delivery of curcumin. The high proapoptotic activity of the system and the sub-cellular mechanisms of cytotoxicity were demonstrated using a chemosensitive HL-60 cell line and its resistant alternative HL-60/DOX. Next, the successful localization of nanocarriers in mitochondria was proved by fluorescence microscopy with the aid of DAPI (4',6-diamidino-2-phenylindole) as a cellular localization tracker. The in vitro experiments revealed the great potential of the functional system developed for the targeted delivery of curcumin to mitochondria, causing programmed tumor cell death.

Functional block copolymer nanocarriers for anticancer drug delivery

We present a synthetic strategy towards functional polymer-based nanocarriers for potential anticancer drug delivery.