Hollow poly(MPC-g-PEG-b-PLA) graft copolymer microcapsule as a potential drug carrier

Nanotherapeutics Overcoming the Blood-Brain Barrier for Glioblastoma Treatment

Glioblastoma (GBM) is the most common malignant primary brain tumor with a poor prognosis. The current standard treatment regimen represented by temozolomide/radiotherapy has an average survival time of 14.6 months, while the 5-year survival rate is still less than 5%. New therapeutics are still highly needed to improve the therapeutic outcome of GBM treatment. The blood-brain barrier (BBB) is the main barrier that prevents therapeutic drugs from reaching the brain. Nanotechnologies that enable drug delivery across the BBB hold great promise for the treatment of GBM. This review summarizes various drug delivery systems used to treat glioma and focuses on their approaches for overcoming the BBB to enhance the accumulation of small molecules, protein and gene drugs, etc. in the brain.

Drug-loading capacity of polylactide-based micro- and nanoparticles - Experimental and molecular modeling study

Micro- and nanostructures prepared from biodegradable homopolymers and amphiphilic block copolymers (AmBCs) have found application as drug-delivery systems (DDSs). The ability to accumulate a drug is a very important parameter characterizing a given DDS. This work focuses on the impact of DDS size, the packing of polymer chains in the DDS, and drug - polymer matrix compatibility on the hydrophobic drug - loading capacity (DLC) of nano/microcarriers prepared from a biodegradable polymer or its copolymer. Using experimental measurements in combination with atomistic molecular dynamics simulations, an analysis of curcumin encapsulation in microspheres (MSs) from polylactide (PLA) homopolymer and nanoparticles (NPs) from PLA-block-poly(2-methacryloyloxyethylphosphorylcholine) AmBC was performed. The results show that curcumin has good affinity for the PLA matrix due to its hydrophobic nature. However, the DLC value is limited by the fact that curcumin only accumulates in the peripheral part of these structures. Such uneven drug distribution in the PLA matrix results from the non-homogeneous density of MSs (non-uniform packing of the polymer chains in the coil). The results also indicate that the MSs can retain a greater amount of hydrophobic drug compared to the NPs, which is associated with the formation of drug aggregates inside the PLA microparticles.

Nanogel-electrospinning for controlling the release of water-soluble drugs

Application of electrospun fibers for the purpose of loading and controlled release of water-soluble drugs remains a challenge due to their low carrying effect as well as quick and unstable drug release. In this study, we have developed a novel nanogel-electrospinning technology through which more stable loading and prolonged release of water-soluble drugs was achieved. In brief, nanogel particles synthesized from a chloroquine (CQ)-loaded bovine serum albumin (BSA) solution were prepared and then combined with genipin, a crosslinking agent. The nanogel solution was then crosslinked to prepare an electrospinning solution with an inner mesh structure. Finally, the microfibrous membranes were fabricated by electrospinning the solution. Uniform BSA nanogel particles were wrapped in the fiber membrane and the number of particles increased with the increase of BSA and genipin concentrations. In addition to being loaded within the BSA nanogel particles, CQ was distributed in the fibers as well, which could be clearly identified using ultraviolet-visible spectroscopy (UV-Vis). The physical, chemical, and mechanical properties of nanogel-electrospun microfibers were similar to those of microfibers formed through a conventional electrospinning approach. The drug release tests indicated that with the same number of BSA nanogel particles, increased CQ loading resulted in increased initial release of the same. The duration of a single drug release cycle lasted up to 40 days. In conclusion, findings from this study have indicated that nanogel-electrospinning is a convenient and effective technology to achieve controlled long-term release of water-soluble drugs.

Cell membrane-inspired phospholipid polymers for developing medical devices with excellent biointerfaces

This review article describes fundamental aspects of cell membrane-inspired phospholipid polymers and their usefulness in the development of medical devices. Since the early 1990s, polymers composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) units have been considered in the preparation of biomaterials. MPC polymers can provide an artificial cell membrane structure at the surface and serve as excellent biointerfaces between artificial and biological systems. They have also been applied in the surface modification of some medical devices including long-term implantable artificial organs. An MPC polymer biointerface can suppress unfavorable biological reactions such as protein adsorption and cell adhesion - in other words, specific biomolecules immobilized on an MPC polymer surface retain their original functions. MPC polymers are also being increasingly used for creating biointerfaces with artificial cell membrane structures.