Pharmaceutical feasibility and flow characteristics of polymeric non-spherical particles

Features of Anisotropic Drug Delivery Systems

Natural materials are anisotropic. Delivery systems occurring in nature, such as viruses, blood cells, pollen, and many others, do have anisotropy, while delivery systems made artificially are mostly isotropic. There is apparent complexity in engineering anisotropic particles or capsules with micron and submicron sizes. Nevertheless, some promising examples of how to fabricate particles with anisotropic shapes or having anisotropic chemical and/or physical properties are developed. Anisotropy of particles, once they face biological systems, influences their behavior. Internalization by the cells, flow in the bloodstream, biodistribution over organs and tissues, directed release, and toxicity of particles regardless of the same chemistry are all reported to be factors of anisotropy of delivery systems. Here, the current methods are reviewed to introduce anisotropy to particles or capsules, including loading with various therapeutic cargo, variable physical properties primarily by anisotropic magnetic properties, controlling directional motion, and making Janus particles. The advantages of combining different anisotropy in one entity for delivery and common problems and limitations for fabrication are under discussion.

Construction of targeted delivery system for curcumin loaded on magnetic α-Fe2O3/Fe3O4 heterogeneous nanotubes and its apoptosis mechanism on MCF-7 cell

In this work, the magnetic α-Fe₂O₃/Fe₃O₄ heterogeneous nanotubes were successfully prepared by solvent hydrothermal-controlled calcination method. The effects of additive concentration, hydrothermal temperature and time on morphology of products were investigated. The α-Fe₂O₃/Fe₃O₄ nanotubes with a saturation magnetization of 50 emu/g were prepared calcinated at 600 °C for 4 h using 0.8 g of glucose. Their average length, the outer and inner diameters were around 240 nm, 178 nm and 145 nm, respectively. The α-Fe₂O₃/Fe₃O₄ heterogeneous nanotubes coated with water-soluble liposome were applied for targeted delivery of curcumin. The release of curcumin inside the hollow structure of the nanocomposites could be triggered and effectively sustained represented a process of slow release. The encapsulation efficiency of curcumin in the α-Fe₂O₃/Fe₃O₄-CUR@LIP nanocomposites reached 82.1 ± 0.9%. MTT assays demonstrated that blank carriers had excellent biocompatibility and application of magnetic field significantly elevated the cytotoxicity of α-Fe₂O₃/Fe₃O₄-CUR@LIP nanocomposites on MCF-7 cell. Electrochemical experiment and Prussian blue staining indicated that the α-Fe₂O₃/Fe₃O₄@LIP nanocomposites could aggregate in cells to promote the internalization of curcumin. Magnetic α-Fe₂O₃/Fe₃O₄-CUR@LIP nanocomposites and curcumin enhanced the expression of reactive oxygen species in MCF-7 cells and induced apoptosis by fluorescence detection. Flow cytometry and western blot verified that the α-Fe₂O₃/Fe₃O₄@LIP nanocomposites under magnetic field enhanced cells late-apoptosis by adjusting the expression of apoptosis-related proteins.

Synthetic polymer material modified by d-peptide and its targeted application in the treatment of non-small cell lung cancer

Liposomes functionalized with targeted material offer a breakthrough compared with passive drug delivery. Here, we designed a polymer material, VAP-PEG₃₃₅₀-DSPE (VAP-PEG-DSPE), modified with a d-peptide VAP ligand that combines tumor-homing VAP with GRP78 receptor, a cancer marker on the membranes of many cancer cells. This paper establishes a docetaxel-loaded lipid nanodisk modified with multifunctional material to evaluate its anti-NSCLC efficacy in vivo. Additionally, the present study verified that VAP-conjugated nanodisks adapt to the developed tumor vasculature of the lung cancer microenvironment, making it a promising nanocarrier for NSCLC-targeting therapy. Moreover, in vitro and in vivo experiments demonstrated the targeting ability of VAP-DISK/DTX to tumor cells. Lung slices of mice also demonstrated the safety of VAP-DISK/DTX. The encapsulation efficiency of docetaxel-disks (VAP-DISK/DTX) was as high as 92.46±4.48%. Encapsulating anti-cancer drugs in lipid nanoparticles is thus an effective mechanism to change the pharmacokinetic and pharmacodynamic characteristics of drugs.

Polymeric nanostructures based on azobenzene and their biomedical applications: synthesis, self-assembly and stimuli-responsiveness

Amphiphilic polymers can self-assemble to form nanoparticles with different structures under suitable conditions. Polymer nanoparticles functionalized with aromatic azo groups are endowed with photo-responsive properties. In recent years, a variety of photoresponsive polymers and nanoparticles have been developed based on azobenzene, using different molecular design strategies and synthetic routes. This article reviews the progress of this rapidly developing research field, focusing on the structure, synthesis, assembly and response of photo-responsive polymer assemblies. According to the molecular structure, photo-responsive polymers can be divided into linear polymers containing azobenzene in a side chain, linear polymers containing azobenzene in the main chain, linear polymers containing azobenzene in an end group, branched polymers containing azobenzene and supramolecular polymers containing azobenzene. These systems have broad biomedical application prospects in the field of drug delivery and imaging applications.

Precision Wormlike Nanoadjuvant Governs Potency of Vaccination

It remains unclear how the precise length of one-dimensional nanovehicles influences the characters of vaccination. Here, a unimolecular nanovehicle with tailored size and aspect ratio (AR) is applied to deliver CpG oligodeoxynucleotide, a Toll-like receptor (TLR) 9 agonist, as an adjuvant of recombinant hepatitis B virus surface antigen (rHBsAg), for treating chronic hepatitis B (CHB). Cationic nanovehicles with fixed width (ca. 45 nm) but varied length (46 nm-180 nm), AR from 1 to 4, are prepared through controlled polymerization and are loaded with CpG by electrostatic interaction. We reveal that the nanoadjuvant with AR = 2 shows the highest retention in proximal lymph nodes. Importantly, it is more easily internalized into antigen-presenting cells and accumulates in the late endosome, where TLR9 is located. Such a nanoadjuvant exhibits the strongest immune response with rHBsAg to clear the hepatitis B virus in the CHB mouse model, showing that the AR of nanovehicles governs the efficiency of vaccination.

Fabrication and evaluation of artemether loaded polymeric nanorods obtained by mechanical stretching of nanospheres

The objective of the present study was to prepare and evaluate artemether-loaded poly (lactic-co-glycolic acid) (PLGA) nanorods by mechanical stretching of nanospheres. Artemether-loaded PLGA nanospheres were prepared by the standard nanoprecipitation method. To prepare the nanorods, nanospheres (129 nm) were embedded in polyvinyl alcohol film. The film was stretched by using an in-house fabricated film stretching apparatus in one dimension at the rate of 10 mm/min in acetone or silicon oil. Nanorods were recovered by dissolving the film in Milli-Q-water after stretching. The effect of film thickness (100 µm vs 150 µm), the ratio of lactide to glycolide in PLGA (50:50 vs 75:25), extent of stretching (2x vs 4x), on the aspect ratio of the nanorods was studied. A sustained release of artemether was observed from both nanospheres and nanorods with almost 85% drug release at the end of 72 h. In cytotoxicity study, almost 90% cell viability was found when THP-1 cells were treated with artemether, nanospheres, and nanorods equivalent to 0.001 to 100 µg/mL of artemether. At all the concentrations of artemether, nanorods showed less haemolysis of RBCs than the nanospheres. Artemether-loaded PLGA nanorods could be successfully prepared by the film stretching method for intravenous delivery of antimalarial drugs.

Morphological modulation of azobenzene-containing tubular polymersomes

Several external factors influencing the formation and morphologic transition of tubular vesicles were carefully investigated, including the initial polymer concentration, solvent, temperature, water adding rate, and light irradiation.

Smart azobenzene-containing tubular polymersomes: fabrication and multiple morphological tuning

A fundamental challenge in nanomaterial science is to facilely fabricate nonspherical polymersomes. Here, several kinds of novel tubular polymersomes were fabricated via self-assembly of amphiphilic azobenzene-containing block copolymers. Besides, their shape could be tuned by multiple approaches including changes in the chemical structure, self-assembly conditions and external stimuli.