Formation, characterization and application of arginine-modified chitosan/γ-poly glutamic acid nanoparticles as carrier for curcumin

Preparation, Characterization and Drug Delivery Research of γ-Polyglutamic Acid Nanoparticles: A Review

γ-Polyglutamic acid is a kind of biomaterial and environmentally friendly polymer material with the characteristics of water solubility and good biocompatibility. It has a wide range of applications in medicine, food, cosmetics and other fields. This article reviews the preparation, characterization and medical applications of γ-polyglutamic acid nanoparticles. Nanoparticles prepared by using γ- polyglutamic acid not only had the traditional advantages of enhancing drug stability and slow-release effect, but also were simple to prepare without any biological toxicity. The current methods of nanoparticle preparation mainly include the ion gel method and solvent exchange method, which use the total electrostatic force, van der Waals force, hydrophobic interaction force and hydrogen bond force between molecules to embed materials with different characteristics. At present, there are more and more studies on the use of γ-polyglutamic acid to encapsulate drugs, and the research on the mechanism of its encapsulation and sustained release has gradually matured. The development and application of polyglutamic acid nanoparticles have broad prospects.

Biofabricated poly (γ-glutamic acid) bio-ink reinforced with calcium silicate exhibiting superior mechanical properties and biocompatibility for bone regeneration

Background/purpose

The modification in 3D hydrogels, tissue engineering, and biomaterials science has enabled us to fabricate novel substitutes for bone regeneration. This study aimed to combine different biomaterials by 3D technique to fabricate a promising all-rounded hydrogel for bone regeneration.

Materials and methods

In this study, glycidyl methacrylate (GMA)-modified poly γ-glutamic acid (γ-PGA-GMA) hydrogels with calcium silicate (CS) hydrogel of different concentrations were fabricated by a 3D printing technique, and their biocompatibility and capability in bone regeneration were also evaluated.

Results

The results showed that CS γ-PGA-GMA could be successfully fabricated, and the presence of CS enhanced the rheological and mechanical properties of γ-PGA-GMA hydrogels, thus making them more adept at 3D printing and implantations. SEM images of the surface structure showed that higher CS concentrations (5% and 10%) contributed to denser surface architectures, thus achieving improved cellular adhesion and stem cell proliferation. Furthermore, higher concentrations of CS resulted in elevated expressions of osteogenic-related markers such as alkaline phosphatase (ALP) and osteocalcin (OC), as well as enhanced calcium deposition represented by the increased Alizarin Red S staining. In vivo studies referring to critical defects of rabbit femur further showed that the existence of hydrogels alone was able to induce partial bone regeneration, demonstrated by the results from quantitative and qualitative analysis of micro-CT scans. However, CS alterations caused significant increases in bone regeneration, as indicated by micro-CT and histological staining.

Conclusion

These results robustly suggest combining different biomaterials is crucial to producing a well-rounded hydrogel for tissue regeneration. We hope this study could be applied as a platform for others to brainstorm potential out-of-the-box solutions, contributing to developing high-potential biomaterials for bone regeneration.

Coupling fermentation of glutamic acid and γ-polyglutamic acid and preparation of poly(amino acid) superabsorbent polymers

γ-polyglutamic acid (γ-PGA) is a biomarker that can be directly obtained by microbial fermentation. Poly(amino acid) superabsorbent polymers (SAPs) were prepared with purified γ-PGA as raw material and ethylene glycol diglycidyl ether (EGDGE) as a cross-linking agent. However, γ-PGA fermentation broth has a high viscosity, requires complex extraction and separation processes, and entails high energy consumption, resulting in the high cost of poly (amino acid) SAPs. Therefore, the coupling fermentation processes of glutamate polyglutamic acid, the process of using glutamate fermentation broth instead of pure glutamate powder for fermentation, and the process of treating the fermentation broth under conditions of centrifugation, UV irradiation, and high temperature, were studied. The results showed that the yield of γ-PGA after centrifugation decreased by 5%, but it did not affect the synthesis of hydrogels, and the addition of γ-PGA fermentation broth had a significant effect on the performance of γ-PGA-co-PASP SAPs. The proposed method not only helps avoid the separation of complex γ-PGA fermentation broth and reduces the cost, but it also helps improve the performance of the super-absorbent resin, which has great application potential.

Preparation of carboxymethylcellulose / ZnO / chitosan composite hydrogel microbeads and its drug release behaviour

In this study, a novel carboxymethylcellulose / ZnO / chitosan (CMC / ZnO / Cs) hydrogel microbeads loaded with crosslinked porous starch / curcumin (CPS / Cur) were designed and prepared to improve the encapsulation efficiency of curcumin for drug delivery to specific sites. It was found that the total pore volume of crosslinked porous starch (CPS) was increased by 1150 % when compared to the native starch (NS), and the adsorption ratio of curcumin by CPS was enhanced by 27 % when compared to NS. Secondly, the swelling ratio of composite hydrogel microbeads was within 25 % in an acidic environment at pH 1.2, and the swelling ratio of hydrogel microbeads sharply increased to 320 % ~ 370 % at pH 6.8 and 7.4. In addition, the results of in vitro simulated release experiments showed that the released amount of hydrogel microbeads loaded with NS/Cur and CPS/Cur in SGF were within 7 % in simulated gastric fluid (SGF). The highest released amount of curcumin was 65.26 % for hydrogel beads loaded with CPS/Cur, which was 26 % lower than that of hydrogel microbeads loaded with Cur in simulated intestinal fluid (SIF). In simulated colonic fluid (SCF), the released amount of hydrogel microbeads loaded with CPS/Cur and Cur were 73.96 % and 91.69 %, respectively. In conclusion, pH-sensitive drug delivery system with good drug stability and bioavailability were successfully prepared with carboxymethylcellulose / ZnO / chitosan bead, suitable targeting drug delivery to the small intestine.

Palmitic acid- and cysteine-functionalized nanoparticles overcome mucus and epithelial barrier for oral delivery of drug

Nanoparticles (NPs) used for oral administration have greatly improved drug bioavailability and therapeutic efficacy. Nevertheless, NPs are limited by biological barriers, such as gastrointestinal degradation, mucus barrier, and epithelial barrier. To solve these problems, we developed the PA-N-2-HACC-Cys NPs loaded with anti-inflammatory hydrophobic drug curcumin (CUR) (CUR@PA-N-2-HACC-Cys NPs) by self-assembled amphiphilic polymer, composed of the N-2-Hydroxypropyl trimethyl ammonium chloride chitosan (N-2-HACC), hydrophobic palmitic acid (PA), and cysteine (Cys). After oral administration, the CUR@PA-N-2-HACC-Cys NPs had good stability and sustained release under gastrointestinal conditions, followed by adhering to the intestine to achieve drug mucosal delivery. Additionally, the NPs could penetrate mucus and epithelial barriers to promote cellular uptake. The CUR@PA-N-2-HACC-Cys NPs could open tight junctions between cells for transepithelial transport while striking a balance between mucus interaction and diffusion through mucus. Notably, the CUR@PA-N-2-HACC-Cys NPs improved the oral bioavailability of CUR, which remarkably relieved colitis symptoms and promoted mucosal epithelial repair. Our findings proved that the CUR@PA-N-2-HACC-Cys NPs had excellent biocompatibility, could overcome mucus and epithelial barriers, and had significant application prospects for oral delivery of the hydrophobic drugs.

Potential Oral Anticancer Therapeutic Agents of Hexahydrocurcumin-Encapsulated Chitosan Nanoparticles against MDA-MB-231 Breast Cancer Cells

Hexahydrocurcumin-encapsulated chitosan nanoparticles (HHC-CS-NPs) were formulated by oil-in-water emulsification and ionotropic gelation and optimized using the Box-Behnken design. The particle size, zeta potential, and encapsulation efficiency of the optimized HHC-CS-NPs were 256 ± 14 nm, 27.3 ± 0.7 mV, and 90.6 ± 1.7%, respectively. The TEM analysis showed a spherical shape and a dense structure with a narrow size distribution. The FT-IR analysis indicated no chemical interaction between the excipients and the drugs in the nanoparticles, but the existence of the drugs was molecularly dispersed in the nanoparticle matrices. The drug release profile showed a preliminary burst release followed by a sustained release under simulated gastrointestinal (GI) and physiological conditions. A stability study suggested that the HHC-CS-NPs were stable under UV light, simulated GI, and body fluids. The in vitro bioaccessibility and bioavailability of the HHC-CS-NPs were 2.2 and 6.1 times higher than those of the HHC solution, respectively. The in vitro evaluation of the antioxidant, anti-inflammatory, and cytotoxic effects of the optimized HHC-CS-NPs demonstrated that the CS-NPs significantly improved the biological activities of HHC in radical scavenging, hemolysis protection activity, anti-protein denaturation, and cytotoxicity against MDA-MB-231 breast cancer cells. Western blot analysis showed that the apoptotic protein expression of Bax, cytochrome C, caspase-3, and caspase-9, were significantly up-regulated, whereas the anti-apoptotic protein Bcl-2 expression was down-regulated in the HHC-CS-NP-treated cells. Our findings suggest that the optimized HHC-CS-NPs can be further developed as an efficient oral treatment for breast cancer.

Preparation, characterization of PLGA/chitosan nanoparticles as a delivery system for controlled release of DHA

In this work, a novel DHA-loaded nanoparticle with PLGA and chitosan (PCSDNP) was successfully prepared. The structure of PCSDNP and DHA-loaded PLGA nanoparticles was measured by transmission electron microscope, scanning electron microscope, and differential scanning calorimeter. The interaction strength between DHA, PLGA, and chitosan was evaluated through Fourier transform infrared spectroscopy. The curves of controlled DHA release and stabilities for different environmental factors of two NPs were evaluated. Importantly, two NPs were almost regularly spherical and the interactions were hydrogen bonds and electrostatic interactions between PLGA and chitosan. These NPs had a good encapsulation rate (80.45%) and high-water solubility than the free DHA molecule. In simulated gastrointestinal fluid, two NPs showed a controlled-release pattern. Overall, PCSDNP had better stability and controlled-release effect with the synergy between CS and PLGA under the conditions of pH (2- 7), ionic strength (0- 500 mM), storage time (0- 42 d), and temperature (30- 80 °C).

Drug delivery applications of poly-γ-glutamic acid

Background

Poly-γ-glutamic acid (γ-PGA) is a biopolymer of microbial origin, consisting of repeating units of l-glutamic acid and/or D-glutamic acid. The biopolymer has found use in the fields of agriculture, food, wastewater, and medicine, owing to its non-toxic, biodegradable, and biocompatible properties. Due to its biodegradability, γ-PGA is being tipped to dislodge synthetic plastics in drug delivery application. High cost of production, relative to plastics, is however a clog in the wheel of achieving this.

Main body of abstract

This review looked at the production, nanoparticles fabrication, and drug delivery application of γ-PGA. γ-PGA production optimization by modifying the fermentation medium to tailor towards the production of desirable polymer at reduced cost and techniques for the formulation of γ-PGA nanoparticle as well as its characterization were discussed. This review also evaluated the application of γ-PGA and its nanoparticles in the delivery of drugs to action site. Characterization of γ-PGA and its nanoparticles is a crucial step towards determining the applicability of the biopolymer. γ-PGA has been used in the delivery of active agents to action sites.

Conclusion

This review highlights some of the efforts that have been made in the appraisal of γ-PGA and its nanoparticles for drug delivery. γ-PGA is a candidate for future extensive use in drug delivery.