Formulation and characterization of poly(propylacrylic acid)/poly(lactic-co-glycolic acid) blend microparticles for pH-dependent membrane disruption and cytosolic delivery

Harnessing Immunomodulatory Polymers for Treatment of Autoimmunity, Allergy, and Transplant Rejection

Autoimmunity, allergy, and transplant rejection are a collection of chronic diseases that are currently incurable, drastically decrease patient quality of life, and consume considerable health care resources. Underlying each of these diseases is a dysregulated immune system that results in the mounting of an inflammatory response against self or an innocuous antigen. As a consequence, afflicted patients are required to adhere to lifelong regimens of multiple immunomodulatory drugs to control disease and reclaim agency. Unfortunately, current immunomodulatory drugs are associated with a myriad of side effects and adverse events, such as increased risk of cancer and increased risk of serious infection, which negatively impacts patient adherence rates and quality of life. The field of immunoengineering is a new discipline that aims to harness endogenous biological pathways to thwart disease and minimize side effects using novel biomaterial-based strategies. We highlight and discuss polymeric micro/nanoparticles with inherent immunomodulatory properties that are currently under investigation in biomaterial-based therapies for treatment of autoimmunity, allergy, and transplant rejection.

Farnesol delivery via polymeric nanoparticle carriers inhibits cariogenic cross-kingdom biofilms and prevents enamel demineralization

Streptococcus mutans and Candida albicans are frequently detected together in the plaque from patients with early childhood caries (ECC) and synergistically interact to form a cariogenic cross-kingdom biofilm. However, this biofilm is difficult to control. Thus, to achieve maximal efficacy within the complex biofilm microenvironment, nanoparticle carriers have shown increased interest in treating oral biofilms in recent years. Here, we assessed the anti-biofilm efficacy of farnesol (Far), a hydrophobic antibacterial drug and repressor of Candida filamentous forms, against cross-kingdom biofilms employing drug delivery via polymeric nanoparticle carriers (NPCs). We also evaluated the effect of the strategy on teeth enamel demineralization. The farnesol-loaded NPCs (NPC+Far) resulted in a 2-log CFU/mL reduction of S. mutans and C. albicans (hydroxyapatite disc biofilm model). High-resolution confocal images further confirmed a significant reduction in exopolysaccharides, smaller microcolonies of S. mutans, and no hyphal form of C. albicans after treatment with NPC+Far on human tooth enamel (HT) slabs, altering the biofilm 3D structure. Furthermore, NPC+Far treatment was highly effective in preventing enamel demineralization on HT, reducing lesion depth (79% reduction) and mineral loss (85% reduction) versus vehicle PBS-treated HT, while NPC or Far alone had no differences with the PBS. The drug delivery via polymeric NPCs has the potential for targeting bacterial-fungal biofilms associated with a prevalent and costly pediatric oral disease, such as ECC.

The roadmap to micro: Generation of micron-sized polymeric particles using a commercial microfluidic system

Microfluidic-assisted particle fabrication provides a route to circumvent the disadvantages associated with traditional methods of polymeric particle generation, such as low drug loading efficiency, challenges in controlling encapsulated drug release rates, batch-to-batch variability in particle physical properties and formulation instability. However, this approach primarily produces particles with nanometer size dimensions, which limits drug delivery modalities. Herein, we systematically studied parameters for the generation of micron-sized poly(lactic-co-glycolic) acid (PLGA) particles using a microfluidic system, the NanoAssemblr benchtop. Initially, we used two organic solvents that have been reported suitable for the fabrication of PLGA nanoparticles - acetone and acetonitrile. Subsequently, we methodically manipulated polymer concentration, organic: aqueous flow rate ratios, total flow rate, organic phase composition, and surfactant concentration to develop a route for the fabrication of micron-sized PLGA particles. Further, we incorporated hydroxychloroquine (HCQ), a clinically approved drug for malaria and lymphoma, and measured how its incorporation impacted particle physicochemical properties. Briefly, altering the organic phase composition by including ethyl acetate (less polar solvent), resulted in micron-scale particles, as well as increased polydispersity indexes (PDIs). Adjusting the surfactant concentration of poly vinyl alcohol (PVA) after the addition of these solvent mixtures rendered large particles with lower PDI variability. Moreover, encapsulation of HCQ influenced particle hydrodynamic diameter and PDI in a PVA concentration dependent manner. Finally, we demonstrated that unloaded and HCQ-loaded microparticles did not affect the viability of RAW 264.7 macrophages. This study provides an itinerary for fabricating biocompatible, drug-loaded, micron-sized polymeric particles, particularly when the drug of interest is not readily soluble in conventional organic solvents.

Pickering Emulsions and Antibubbles Stabilized by PLA/PLGA Nanoparticles

Micrometer-sized double emulsions and antibubbles were produced and stabilized via the Pickering mechanism by colloidal interfacial layers of polymeric nanoparticles (NPs). Two types of nanoparticles, consisting either of polylactic acid (PLA) or polylactic-co-glycolic acid (PLGA), were synthesized by the antisolvent technique without requiring any surfactant. PLA nanoparticles were able to stabilize water-in-oil (W/O) emulsions only after tuning the hydrophobicity by means of a thermal treatment. A water-in-oil-in-water (W/O/W) emulsion was realized by emulsifying the previous W/O emulsion in a continuous water phase containing hydrophilic PLGA nanoparticles. Both inner and outer water phases contained a sugar capable of forming a glassy phase, while the oil was crystallizable upon freezing. Freeze drying the double emulsion allowed removing the oil and water and replacing them with air without losing the three-dimensional (3D) structure of the original emulsion owing to the sugar glassy phase. Reconstitution of the freeze-dried double emulsion in water yielded a dispersion of antibubbles, i.e., micrometric bubbles containing aqueous droplets, with the interfaces of the antibubbles being stabilized by a layer of adsorbed polymeric nanoparticles. Remarkably, it was possible to achieve controlled release of a flourescent probe (calcein) from the antibubbles through heating to 37 °C leading to bursting of the antibubbles.

Biomaterial-based immunotherapeutic strategies for rheumatoid arthritis

Rheumatoid arthritis (RA) is an extremely painful autoimmune disease characterized by chronic joint inflammation leading to the erosion of adjacent cartilage and bone. Rheumatoid arthritis pathology is primarily driven by inappropriate infiltration and activation of immune cells within the synovium of the joint. There is no cure for RA. As such, manifestation of symptoms entails lifelong management via various therapies that aim to generally dampen the immune system or impede the function of immune mediators. However, these treatment strategies lead to adverse effects such as toxicity, general immunosuppression, and increased risk of infection. In pursuit of safer and more efficacious therapies, many emerging biomaterial-based strategies are being developed to improve payload delivery, specific targeting, and dose efficacy, and to mitigate adverse reactions and toxicity. In this review, we highlight biomaterial-based approaches that are currently under investigation to circumvent the limitations of conventional RA treatments.

Brigatinib loaded poly(d,l-lactide-co-glycolide) nanoparticles for improved anti-tumoral activity against non-small cell lung cancer cell lines

OBJECTIVE

The aim of the current investigation was to develop poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) to sustain the brigatinib (BTB) release for prolong time period and to examine the antitumor effect of the optimized NPs.

SIGNIFICANCE

Optimized PLGA-based NPs of BTB could be potentially used as a promising nanocarrier for the treatment of non-small cell lung cancer.

METHODS

BTB-loaded NPs were fabricated with core-shell of PLGA by solvent evaporation technique using different proportions of PLGA polymer and poly-vinyl alcohol (PVA) stabilizer. The prepared NPs were evaluated for particle characterizations; size, polydispersity index (PDI), zeta-potential, entrapment efficiency (EE), and drug loading (DL), Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction studies. The optimized NPs (BN5) were further evaluated for morphology, stability, and cytotoxicity studies against A549 cell-lines.

RESULTS

Among the nine different NPs formulae (BN1-BN9), BN5 was optimized with composition of BTB (30 mg), PLGA (75 mg), PVA (0.55% w/v), represents an average particle size of (267.1 ± 1.01 nm), PDI (0.101 ± 0.007), and zeta potential (-42.1 ± 0.75 mV), high EE (66.83 ± 0.06%), and DL (6.17 ± 0.69%). SEM image of selected NPs was spherical with smooth surface. In vitro drug release profile in phosphate buffers (pH 5 and pH 7.4) showed a biphasic release with initial burst phase followed by sustained release for prolong time. Furthermore, optimized NPs (BN5) exhibited excellent cytotoxic activity against A549 cell-lines with IC₅₀ value of 5.25 ± 0.23 µg/mL.

CONCLUSION

The overall results suggest that BTB-loaded PLGA NPs could be a potential nanocarrier for lung cancer treatment.

The composite microbeads of alginate, carrageenan, gelatin, and poly(lactic-co-glycolic acid): Synthesis, characterization and Density Functional Theory calculations

Binary (AC, AG), ternary (ACG, ACP, AGP), quaternary (ACGP) composite beads of alginate (A), carrageenan (C), gelatin (G), and poly (lactic-co-glycolic acid) (P) were prepared. The dried beads had a 700 μm average diameter. The microspheres with and without P were characterized by FT-IR, TGA/DTA, SEM, and PZC analysis. The results proved that the features of the composites were completely different from their bare components. Density Functional Theory (DFT) calculations were performed at the B3LYP/6-311++G** level to enlighten the elementary physical and chemical properties of A, C, P, and G compounds. The vibrational modes obtained by calculations were compared with those observed in the FT-IR spectra. The Frontier Molecular Orbital (FMO) analyses showed that the component G was the softer and had smaller energy gap than the other components and vice versa for component P. NBO (Natural Bond Orbital) analyses implied that the n → П* (resonance) interactions for components A, G, and P contributed to the lowering of the molecular stabilization, whereas that the n → σ* (anomeric) interactions were responsible for decreasing of the stabilization of the component. From the obtained results, these kinds of components can be hoped the promising materials for usage in the many scientific fields, especially in medicine and in drug design.

pH-Responsive Amphiphilic Carboxylate Polymers: Design and Potential for Endosomal Escape

The intracellular delivery of emerging biomacromolecular therapeutics, such as genes, peptides, and proteins, remains a great challenge. Unlike small hydrophobic drugs, these biotherapeutics are impermeable to the cell membrane, thus relying on the endocytic pathways for cell entry. After endocytosis, they are entrapped in the endosomes and finally degraded in lysosomes. To overcome these barriers, many carriers have been developed to facilitate the endosomal escape of these biomacromolecules. This mini-review focuses on the development of anionic pH-responsive amphiphilic carboxylate polymers for endosomal escape applications, including the design and synthesis of these polymers, the mechanistic insights of their endosomal escape capability, the challenges in the field, and future opportunities.

Layer-by-layer pH-sensitive nanoparticles for drug delivery and controlled release with improved therapeutic efficacy in vivo

In this work, a pH-sensitive liposome-polymer nanoparticle (NP) composed of lipid, hyaluronic acid (HA) and poly(β-amino ester) (PBAE) was prepared using layer-by-layer (LbL) method for doxorubicin (DOX) targeted delivery and controlled release to enhance the cancer treatment efficacy. The NP with pH-sensitivity and targeting effect was successfully prepared by validation of charge reversal and increase of hydrodynamic diameter after each deposition of functional layer. We further showed the DOX-loaded NP had higher drug loading capacity, suitable particle size, spherical morphology, good uniformity, and high serum stability for drug delivery. We confirmed that the drug release profile was triggered by low pH with sustained release manner in vitro. Confocal microscopy research demonstrated that the NP was able to effectively target and deliver DOX into human non-small cell lung carcinoma (A549) cells in comparison to free DOX. Moreover, the blank NP showed negligible cytotoxicity, and the DOX-loaded NP could efficiently induce the apoptosis of A549 cells as well as free DOX. Notably, in vivo experiment results showed that the DOX-loaded NPs effectively inhibited the growth of tumor, enhanced the survival of tumor-bearing mice and improved the therapeutic efficacy with reduced side-effect comparing with free drug. Therefore, the NP could be a potential intelligent anticancer drug delivery carrier for cancer chemotherapy, and the LbL method might be a useful strategy to prepare multi-functional platform for drug delivery.

Accessing Intracellular Targets through Nanocarrier-Mediated Cytosolic Protein Delivery

Protein-based therapeutics have unique therapeutic potential due to their specificity, potency, and low toxicity. The vast majority of intracellular applications of proteins require access to the cytosol. Direct entry to the cytosol is challenging due to the impermeability of the cell membrane to proteins. As a result, multiple strategies have focused on endocytic uptake of proteins. Endosomally entrapped cargo, however, can have very low escape efficiency, with protein degradation occurring in acidic endolysosomal compartments. In this review, we briefly discuss endosomal escape strategies and review the strategy of cell membrane fusion, a recent strategy for direct delivery of proteins into the cell cytoplasm.

Stimuli-Responsive Biomaterials for Vaccines and Immunotherapeutic Applications

The immune system is the key target for vaccines and immunotherapeutic approaches aimed at blunting infectious diseases, cancer, autoimmunity, and implant rejection. However, systemwide immunomodulation is undesirable due to the severe side effects that typically accompany such strategies. In order to circumvent these undesired, harmful effects, scientists have turned to tailorable biomaterials that can achieve localized, potent release of immune-modulating agents. Specifically, "stimuli-responsive" biomaterials hold a strong promise for delivery of immunotherapeutic agents to the disease site or disease-relevant tissues with high spatial and temporal accuracy. This review provides an overview of stimuli-responsive biomaterials used for targeted immunomodulation. Stimuli-responsive or "environmentally responsive" materials are customized to specifically react to changes in pH, temperature, enzymes, redox environment, photo-stimulation, molecule-binding, magnetic fields, ultrasound-stimulation, and electric fields. Moreover, the latest generation of this class of materials incorporates elements that allow for response to multiple stimuli. These developments, and other stimuli-responsive materials that are on the horizon, are discussed in the context of controlling immune responses.

Cartilage Extracellular Matrix Scaffold With Kartogenin-Encapsulated PLGA Microspheres for Cartilage Regeneration

Repair of articular cartilage defects is a challenging aspect of clinical treatment. Kartogenin (KGN), a small molecular compound, can induce the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) into chondrocytes. Here, we constructed a scaffold based on chondrocyte extracellular matrix (CECM) and poly(lactic-co-glycolic acid) (PLGA) microspheres (MP), which can slowly release KGN, thus enhancing its efficiency. Cell adhesion, live/dead staining, and CCK-8 results indicated that the PLGA(KGN)/CECM scaffold exhibited good biocompatibility. Histological staining and quantitative analysis demonstrated the ability of the PLGA(KGN)/CECM composite scaffold to promote the differentiation of BMSCs. Macroscopic observations, histological tests, and specific marker analysis showed that the regenerated tissues possessed characteristics similar to those of normal hyaline cartilage in a rabbit model. Use of the PLGA(KGN)/CECM scaffold may mimic the regenerative microenvironment, thereby promoting chondrogenic differentiation of BMSCs in vitro and in vivo. Therefore, this innovative composite scaffold may represent a promising approach for acellular cartilage tissue engineering.