Biocompatibility Profile and In Vitro Cellular Uptake of Self-assembled Alginate Nanoparticles

Nanocarrier-based gene delivery for immune cell engineering

Clinical advances in genetically modified immune cell therapies, such as chimeric antigen receptor T cell therapies, have raised hope for cancer treatment. The majority of these biotechnologies are based on viral methods for ex vivo genetic modification of the immune cells, while the non-viral methods are still in the developmental phase. Nanocarriers have been emerging as materials of choice for gene delivery to immune cells. This is due to their versatile physicochemical properties such as large surface area and size that can be optimized to overcome several practical barriers to successful gene delivery. The in vivo nanocarrier-based gene delivery can revolutionize cell-based cancer immunotherapies by replacing the current expensive autologous cell manufacturing with an off-the-shelf biomaterial-based platform. The aim of this research is to review current advances and strategies to overcome the challenges in nanoparticle-based gene delivery and their impact on the efficiency, safety, and specificity of the process. The main focus is on polymeric and lipid-based nanocarriers, and their recent preclinical applications for cancer immunotherapy.

Development of a Novel, Ecologically Friendly Generation of pH-Responsive Alginate Nanosensors: Synthesis, Calibration, and Characterisation

Measurement of the intracellular pH is particularly crucial for the detection of numerous diseases, such as carcinomas, that are characterised by a low intracellular pH. Therefore, pH-responsive nanosensors have been developed by many researchers due to their ability to non-invasively detect minor changes in the pH of many biological systems without causing significant biological damage. However, the existing pH-sensitive nanosensors, such as the polyacrylamide, silica, and quantum dots-based nanosensors, require large quantities of organic solvents that could cause detrimental damage to the ecosystem. As a result, this research is aimed at developing a new generation of pH-responsive nanosensors comprising alginate natural polymers and pH-sensitive fluorophores using an organic, solvent-free, and ecologically friendly method. Herein, we successfully synthesised different models of pH-responsive alginate nanoparticles by varying the method of fluorophore conjugation. The synthesised pH nanosensors demonstrated a low MHD with a relatively acceptable PDI when using the lowest concentration of the cross-linker Ca+2 (1.25 mM). All the pH nanosensors showed negative zeta potential values, attributed to the free carboxylate groups surrounding the nanoparticles' surfaces, which support the colloidal stability of the nanosensors. The synthesised models of pH nanosensors displayed a high pH-responsiveness with various correlations between the pH measurements and the nanosensors' fluorescence signal. In summation, pH-responsive alginate nanosensors produced using organic, solvent-free, green technology could be harnessed as potential diagnostics for the intracellular and extracellular pH measurements of various biological systems.

The Effect of Elasticity of Gelatin Nanoparticles on the Interaction with Macrophages

Gelatin is a biocompatible, biodegradable, cheap, and nontoxic material, which is already used for pharmaceutical applications. Nanoparticles from gelatin (GNPs) are considered a promising delivery system for hydrophilic and macromolecular drugs. Mechanical properties of particles are recognized as an important parameter affecting drug carrier interaction with biological systems. GNPs offer the preparation of particles with different stiffness. GNPs were loaded with Fluorescein isothiocyanate-labeled 150 kDa dextran (FITC-dextran) yielding also different elastic properties. GNPs were visualized using atomic force microscopy (AFM), and force-distance curves from the center of the particles were evaluated for Young's modulus calculation. The prepared GNPs have Young's moduli from 4.12 MPa for soft to 9.8 MPa for stiff particles. Furthermore, cytokine release (IL-6 and TNF-α), cell viability, and cell uptake were determined on macrophage cell lines from mouse (RAW 264.7) and human (dTHP-1 cells, differentiated human monocytic THP-1 cells) origin for soft and stiff GNPs. Both particle types showed good cell compatibility and did not induce IL-6 and TNF-α release from RAW 264.7 and dTHP-1 cells. Stiffer GNPs were internalized into cells faster and to a larger extent.

Mechanism of Enhanced Oral Absorption of a Nano-Drug Delivery System Loaded with Trimethyl Chitosan Derivatives

Introduction

In the previous study, nanoparticles coated with trimethyl chitosan (TMC) derivatives (PPTT-NPs) could promote the oral bioavailability of panax notoginseng saponins (PNS). Herein, we chose PPTT-NPs as a model drug to study the property and mechanism of intestinal absorption in vitro and in vivo.

Methods

The stability of PPTT-NPs was evaluated using simulated gastric fluid and simulated intestinal fluid. The uptake and transport of PPTT-NPs were investigated in Caco-2 and Caco-2&HT29 co-culture cells. The biosafety, intestinal permeability, adhesion, and absorption mechanism of PPTT-NPs were investigated using SD rats in vivo. The live imaging and biodistribution of PPTT-NPs were observed by IVIS. Furthermore, the effects on CYP3A4 of PPTT-NPs were investigated using testosterone as the probe substrate.

Results

The results of the stability assay showed that PPTT-NPs had a strong tolerance to the pH and digestive enzymes in the gastrointestinal environment. In vitro cell experiments showed that the uptake of drugs exhibited a time-dependent. When the ratio of TMC-VB₁₂ and TMC-Cys was 1:3, the uptake capacity of PPTT-NPs was the highest. PPTT-NPs could enhance the paracellular transport of drugs by reversibly opening a tight junction. Animal experiments demonstrated that PPTT-NPs have good biological safety. PPTT-NPs had good adhesion and permeability to small intestinal mucosa. Meanwhile, PPTT-NPs needed energy and various protein to participate in the uptake of drugs. The live imaging of NPs illustrated that PPTT-NPs could prolong the residence time in the intestine. Moreover, TMC-VB₁₂ and TMC-Cys could reduce the metabolism of drugs by inhibiting CYP3A4 to a certain extent.

Conclusion

The results show that TMC-VB₁₂ and TMC-Cys are effective in the transport of PPTT-NPs. PPTT-NPs can increase the intestinal adhesion of drugs and exert high permeation by intestinal enterocytes which demonstrate significant and efficient potential for oral delivery of the BCS III drugs.

Synthesis, Self-Assembly, and Cell Responses of Aromatic IKVAV Peptide Amphiphiles

Synthetic bioactive aromatic peptide amphiphiles have been recognized as key elements of emerging biomedical strategies due to their biocompatibility, design flexibility, and functionality. Inspired by natural proteins, we synthesized two supramolecular materials of phenyl-capped Ile-Lys-Val-Ala-Val (Ben-IKVAV) and perfluorophenyl-capped Ile-Lys-Val-Ala-Val (PFB-IKVAV). We employed UV-vis absorption, fluorescence, circular dichroism, and Fourier-transform infrared spectroscopy to examine the driving force in the self-assembly of the newly discovered materials. It was found that both compounds exhibited ordered π-π interactions and secondary structures, especially PFB-IKVAV. The cytotoxicity of human mesenchymal stem cells (hMSCs) and cell differentiation studies was also performed. In addition, the immunofluorescent staining for neuronal-specific markers of MAP2 was 4.6 times (neural induction medium in the presence of PFB-IKVAV) that of the neural induction medium (control) on day 7. From analyzing the expression of neuronal-specific markers in hMSCs, it can be concluded that PFB-IKVAV may be a potential supramolecular biomaterial for biomedical applications.

Optimization of the spherical integrity for sustained-release alginate microcarriers-encapsulated doxorubicin by the Taguchi method

This study aimed to develop biodegradable calcium alginate microcarriers with uniform particle size and spherical integrity for sustained-release targeting transarterial chemoembolization. To determine related parameters including the ratio of cross-linking volume (sodium alginate: CaCl₂), concentrations of sodium alginate and CaCl₂ solutions, collection distance, flow rate, stirring speed, syringe needle diameter and hardening time to fabricate the microcarriers, the Taguchi method was applied. Using different conditions, a total of 18 groups were prepared. The average size of microspheres from different groups was estimated as ~ 2 mm (range 1.1 to 1.6 mm). Signal-to-noise ratio analysis showed the optimal spherical integrity (F1) achieved when the above parameters were designed as 0.1, 2.5 wt%, 6 wt%, 8 cm, 30 mL/h, 150 rpm, 0.25 mm and 2 h, respectively. The best (F1), middle (F2) and worst (F3) groups were used for further experiments. Fourier-transform infrared spectroscopy spectrum showed that F1, F2 and F3 conformations were distinct from original sodium alginate. Drug-loaded calcium alginate microcarriers demonstrated rougher surfaces compared to microspheres without drug under transmission electron microscopy. Compared to pH 7.4, swelling rates in PBS were decreased at pH 6.5. Encapsulation and loaded efficiencies of the Dox-loaded microcarriers were estimated as ~ 40.617% and ~ 3.517%. In vitro experiments indicated that the F1 Dox-loaded microcarriers provide a well sustained-release efficacy for about two weeks at 37 °C in PBS. Treatments of calcium alginate microcarriers without the Dox in two distinct hepatocellular carcinoma-derived cell lines, Huh-7 and Hep-3B, indicated that these microcarriers were non-toxic. The Dox-loaded microcarriers displayed sustained-release capacity and reduced cell viabilities to ~ 30% in both cell lines on Day 12.

Enhancement of Skin Wound Healing by rhEGF-Loaded Carboxymethyl Chitosan Nanoparticles

The self-assembly of hydrophobically modified polymers has become a research hotspot due to its wide application in the biomedical field. Recombinant human epidermal growth factors (rhEGFs) are molecules that are able to enhance wound healing; however, they have a short half-life and require sustained action to enhance their mitogenic effect on epithelial cells. Here, we proposed a new delivery system to avoid the inhibition of rhEGF by various enzymes, thus improving its bioavailability and sustained release. The amphiphilic polymer was composed of conjugated linoleic acid (CLA) and carboxymethyl chitosan (CMCS), which were further characterized by fourier transformed infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (1H NMR). Then, the self-assembly behavior of CLA-CMCS (CC) polymer in water was observed in which the particle size of CC decreased from 196 to 155 nm with the degree of CLA substitution increasing. The nanoparticles were loaded with rhEGF and the maximum rhEGF loading efficiency (LE) of CC3 nanoparticles was 82.43 ± 3.14%. Furthermore, CC nanoparticles (NPs) exhibited no cytotoxicity for L929 cells, and cell proliferation activity was well preserved after rhEGF loading to CC-NPs and was comparable to that of free rhEGF. Topically applied rhEGF:CC-NPs significantly accelerated the wound-closure rate in full thickness, which was most probably due to its sustained release and enhanced skin permeation. In conclusion, carboxymethyl chitosan-based nanoparticles were constructed and showed good cytocompatibility. Moreover, these findings also demonstrated the therapeutic potential of rhEGF:CC-NPs as a topical wound-healing drug carrier.

Polymeric nanoparticles based on carboxymethyl chitosan in combination with painless microneedle therapy systems for enhancing transdermal insulin delivery

Biodegradable nanoparticles (NPs) have been frequently used as insulin transdermal delivery vehicles due to their grand bioavailability, better encapsulation, controlled release and less toxic properties. However, the skin's barrier properties prevent insulin-loaded NP permeation at useful levels. Nowadays, microneedles have been spotlighted as novel transdermal delivery systems due to their advantages such as painlessness, efficient penetration and no hazardous residues. Herein, we introduce polymeric nanocarriers based on carboxymethyl chitosan (CMCS) for insulin delivery, combining with microneedle therapy systems, which can rapidly deliver insulin (INS) into the skin. The resulting CMCS-based nanocarriers are spherical nanoparticles with a mean size around 200 nm, which could generate supramolecular micelles to effectively encapsulate insulin (EE% = 83.78 ± 3.73%). A nanocrystalline microneedle array (6 × 6, 75/150 μm) was used to penetrate the stratum corneum (SC) for enhancing transdermal insulin delivery, while minimizing the pain sensation caused by intravenous injection. Compared with the transdermal rate of passive diffusion [2.77 ± 0.64 μg (cm-2 h-1)], the transdermal rate of the insulin-loaded NP combined with microneedle penetration shows a 4.2-fold increase [10.24 ± 1.06 μg (cm-2 h-1)] from permeation experiment in vitro. In vivo hypoglycemic experiments demonstrate the potential of using nanocarrier combination with microneedle arrays for painless insulin delivery through the skin in a clinical setting. Thus, the developed combination scheme of nanoparticles and microneedle arrays offers an effective, user-friendly, and low-toxicity option for diabetes patients requiring long-term and multiple treatments.

Bacterioruberin from Haloarchaea plus dexamethasone in ultra-small macrophage-targeted nanoparticles as potential intestinal repairing agent

Oral administration of antioxidant and anti-inflammatory drugs have the potential to improve the current therapy of inflammatory bowel disease. Success of oral treatments, however, depends on the capacity of drugs to remain structurally stable along the gastrointestinal tract, and on the feasibility of accessing the target cells. Delivering anti-inflammatory and antioxidant drugs to macrophages using targeted nanoparticles, could make treatments more efficient. In this work structural features and in vitro activity of macrophage-targeted nanostructured archaeolipid carriers (NAC) containing the high antioxidant dipolar C50 carotenoid bacterioruberin (BR) plus dexamethasone (Dex): NAC-Dex, are described. Ultra-small (66 nm), -32 mV ζ potential, 1200 μg Dex /ml NAC-Dex, consisted of a compritol and BR core, covered by a shell of sn 2,3 ether linked archaeolipids and Tween 80 (2: 2: 1.2: 3 % w/w) were obtained. NAC-Dex were extensively captured by macrophages and Caco-2 cells and displayed high anti-inflammatory and antioxidant activities on a gut inflammation model made of Caco-2 cells and lipopolysaccharide stimulated THP-1 derived macrophages reducing 65 % and 55 % TNF-α and IL-8 release, respectively and 60 % reactive oxygen species production. NAC-Dex also reversed the morphological changes induced by inflammation and increased the transepithelial electrical resistance, partly reconstituting the barrier function. Activity of BR and Dex in NAC-Dex was partially protected after simulated gastrointestinal digestion, improving the chances of BR-Dex joint activity. Results suggest that oral NAC-Dex deserve further exploration as intestinal barrier repairing agent.

Nanoscale Self-Assembly for Therapeutic Delivery

Self-assembly is the process of association of individual units of a material into highly arranged/ordered structures/patterns. It imparts unique properties to both inorganic and organic structures, so generated, via non-covalent interactions. Currently, self-assembled nanomaterials are finding a wide variety of applications in the area of nanotechnology, imaging techniques, biosensors, biomedical sciences, etc., due to its simplicity, spontaneity, scalability, versatility, and inexpensiveness. Self-assembly of amphiphiles into nanostructures (micelles, vesicles, and hydrogels) happens due to various physical interactions. Recent advancements in the area of drug delivery have opened up newer avenues to develop novel drug delivery systems (DDSs) and self-assembled nanostructures have shown their tremendous potential to be used as facile and efficient materials for this purpose. The main objective of the projected review is to provide readers a concise and straightforward knowledge of basic concepts of supramolecular self-assembly process and how these highly functionalized and efficient nanomaterials can be useful in biomedical applications. Approaches for the self-assembly have been discussed for the fabrication of nanostructures. Advantages and limitations of these systems along with the parameters that are to be taken into consideration while designing a therapeutic delivery vehicle have also been outlined. In this review, various macro- and small-molecule-based systems have been elaborated. Besides, a section on DNA nanostructures as intelligent materials for future applications is also included.

Fabrication of Carboxylmethyl Chitosan Nanocarrier via Self-Assembly for Efficient Delivery of Phenylethyl Resorcinol in B16 Cells

Micro-molecular drugs have special advantages to cope with challenging diseases, however their structure, physical and chemical properties, stability, and pharmacodynamics have more requirements for the way they are delivered into the body. Carrier-based drug delivery systems can circumvent many limited factors of drug delivery and increase their bioavailability. In this context, stable drug nanocarriers of alkaline amino acids (arginine, Arg) modified conjugated linoleic acid-carboxymethyl chitosan (CLA-CMCS) conjugate were developed, which could generate supramolecular micelles to effectively encapsulate the tyrosinase inhibitor phenylethyl resorcinol (PR). The resulting CCA-NPs were spherical nanoparticles with a mean size around 175 nm. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and cellular uptake investigation demonstrated that the CCA-NPs were non-cytotoxic and had excellent cell transport ability. In addition, these CCA-NPs were able to effectively deliver PR and inhibited melanin formation to reduce pigmentation by enhancing cellular uptake. In conclusion, our research indicated that nanocarriers based on self-assembly amphiphilic polymers constituted a promising and effective drug delivery system in hyperpigmentation targeting.