Novel theranostic wounds dressing based on pH responsive alginate hydrogel/graphene oxide/levofloxacin modified silk

Integrating pH sensor with controlled antibiotic release is fabricated on silk to create a theranostic wound dressing. Alginate (ALG) hydrogel and graphene oxide (GO) loaded with levofloxacin (LVX) and a pH indicator are applied to fabricate a pH-responsive theranostic wound dressing. The modified silk color changes from yellow to green in response to elevated skin pH, indicating the skin infection. The semi-quantitative analysis was conducted using ImageJ, revealing significant color changes across the wide range. At elevated pH levels, the ionization of the COOH bonds within ALG induces repulsion among the COO- groups, thereby accelerating the release of the incorporated drug compared to release under lower pH. At an infected pH of 8, ALG hydrogel triggers LVX releasing up to 135.86 ± 0.3 µg, while at a normal pH of 7, theranostic silk releases 123.13 ± 0.26 µg. Incorporating GO onto silk fibers enhances LVX loading and sustains LVX release. Furthermore, these modified silks possess antimicrobial abilities without causing irritation or allergies on the human skin. This theranostic silks represents a major step forward in smart wound care, introducing a versatile platform of smart wound care.

Metal-polyphenol microgels for oral delivery of puerarin to alleviate the onset of diabetes

Puerarin (Pue) is a naturally bioactive compound with many potential functions in regulating blood glucose and lipid metabolism. However, the low bioavailability and rapid elimination in vivo limit the application of Pue in diabetic treatment. Here, we developed a metal-polyphenol-functionalized microgel to effectively deliver Pue in vivo and eventually alleviate the onset of diabetes. Pue was initially encapsulated in alginate beads through electrospray technology, and further immersed in Fe3+ and tannic acid solution from tannic acid (TA)-iron (Fe) coatings (TF). These constructed Pue@SA-TF microgels exhibited uniform spheres with an average size of 367.89 ± 18.74 µm and high encapsulation efficiency of Pue with 61.16 ± 1.39%. In vivo experiments proved that compared with free Pue and microgels without TF coatings, the biological distribution of Pue@SA-TF microgels specifically accumulated in the small intestine, prolonged the retention time of Pue, and achieved a high effectiveness in vivo. Anti-diabetic experimental results showed that Pue@SA-TF microgels significantly improved the levels of blood glucose, blood lipid, and oxidative stress in diabetic mice. Meanwhile, histopathological observations indicated that Pue@SA-TF microgels could significantly alleviate the damage to the liver, kidney, and pancreas in diabetic mice. Our study provided an effective strategy for oral delivery of Pue and achieved high anti-diabetic efficacy.

Design and Evaluation of Liposomal Sulforaphane-Loaded Polyvinyl Alcohol/Polyethylene Glycol (PVA/PEG) Hydrogels as a Novel Drug Delivery System for Wound Healing

Hydrogel scaffold has been widely applied as drug delivery systems for treating skin injuries. However, the poor drug loading and rapid drug release of hydrogel restricted their application. In the current study, we present a nanoliposome containing sulforaphane (SF) as a nano-drug delivery system that is encapsulated within the scaffold hydrogel system to overcome these limitations and improve wound healing. The hydrogel substrate consisting of 10% polyvinyl alcohol (PVA)/5% polyethylene glycol 400 (PEG400) was prepared by the freeze-thaw method, and the nanoliposomal system was manufactured by the thin film hydration method at different molar ratios of cholesterol: SPC: DPPC: DSPE-PEG2000. The nanoliposome and hydrogel system was characterized by physicochemical analyses. The findings achieved from the optimization of the sulforaphane-loaded nanoliposome (SFNL) displayed an increase in the molar ratio of SPC, leading to a higher entrapment efficiency and a gradual release profile. Narrow size distribution, optimal electrical charge, and the lack of molecular interactions between SF and nanoliposome components in the FTIR analysis make SFNL a suitable drug delivery system for the wound healing process. The obtained SFNL-encapsulated freeze-thawed hydrogel system has sufficient and specific swelling ability at different pH values and increased mechanical strength and elongation. Additionally, the release pattern of SFNL at different pH values showed that the release of SF from liposomes depends on the pH value of the environment and accelerates in line with decreasing pH values. Encapsulation of nanoliposomal SF in the hydrogel structure provides a sustained release pattern of SF compared to its free form and increased as the pH environments continued to raise. The cytotoxicity and cell uptake of SFNL-loaded hydrogels against human skin fibroblasts (HFF cell line) were investigated. The in vitro analyses displayed that the toxicity properties of SF and SFNL were dose-dependent, and SFNL exhibited lower toxicity compared to free SF. Furthermore, the proper cell compatibility of the prepared hydrogel against the HFF cell line was confirmed by the MTT assay. These findings imply that the hydrogel scaffold loaded with SFNL may have wound-healing potential.

Insight into the Latest Medical Applications of Nanocellulose

Nanocelluloses (NCs) are appealing nanomaterials that have experienced rapid development in recent years, with great potential in the biomedical field. This trend aligns with the increasing demand for sustainable materials, which will contribute both to an improvement in wellbeing and an extension of human life, and with the demand to keep up with advances in medical technology. In recent years, due to the diversity of their physical and biological properties and the possibility of tuning them according to the desired goal, these nanomaterials represent a point of maximum interest in the medical field. Applications such as tissue engineering, drug delivery, wound dressing, medical implants or those in cardiovascular health are some of the applications in which NCs have been successfully used. This review presents insight into the latest medical applications of NCs, in the forms of cellulose nanocrystals (CNCs), cellulose nanofibers (CNFs) and bacterial nanocellulose (BNC), with an emphasis on the domains that have recently experienced remarkable growth, namely wound dressing, tissue engineering and drug delivery. In order to highlight only the most recent achievements, the presented information is focused on studies from the last 3 years. Approaches to the preparation of NCs are discussed either by top-down (chemical or mechanical degradation) or by bottom-up (biosynthesis) techniques, along with their morphological characterization and unique properties, such as mechanical and biological properties. Finally, the main challenges, limitations and future research directions of NCs are identified in a sustained effort to identify their effective use in biomedical fields.

Synthesis of Gallic Acid-Loaded Chitosan-Grafted-2-Acrylamido-2-Methylpropane Sulfonic Acid Hydrogels for Oral Controlled Drug Delivery: In Vitro Biodegradation, Antioxidant, and Antibacterial Effects

In this study, chitosan (CS) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS)-based hydrogels were formulated by the free radical polymerization technique for the controlled release of gallic acid. Fourier transform infrared spectroscopy (FTIR) confirmed the successful preparation and loading of gallic acid within the hydrogel network. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) confirmed the increased thermal stability of the hydrogels following the crosslinking and polymerization of chitosan and AMPS. In X-ray diffraction analysis (XRD), the crystallinity of the raw materials decreased, indicating strong crosslinking of the reagents and the formation of a new polymeric network of hydrogels. Scanning electron microscopy (SEM) revealed that the hydrogel had a rough, dense, and porous surface, which is consistent with the highly polymerized composition of the hydrogel. After 48 h, the hydrogels exhibited higher swelling at pH 1.2 (swelling ratio of 19.93%) than at pH 7.4 (swelling ratio of 15.65%). The drug release was analyzed using ultraviolet-visible (UV-Vis) spectrophotometer and demonstrated that after 48 h, gallic acid release was maximum at pH 1.2 (85.27%) compared to pH 7.4 (75.19%). The percent porosity (78.36%) and drug loading increased with the increasing concentration of chitosan and AMPS, while a decrease was observed with the increasing concentration of ethylene glycol dimethyl methacrylate (EGDMA). Crosslinking of the hydrogels increased with concentrations of chitosan and EGDMA but decreased with AMPS. In vitro studies demonstrated that the developed hydrogels were biodegradable (8.6% degradation/week) and had antimicrobial (zone of inhibition of 21 and 16 mm against Gram-positive bacteria Escherichia coli and Staphylococcus aureus as well as 13 mm against Gram-negative bacteria Pseudomonas aeruginosa, respectively) and antioxidant (73% DPPH and 70% ABTS) properties. Therefore, the prepared hydrogels could be used as an effective controlled drug delivery system.

Recent Reports on Polysaccharide-Based Materials for Drug Delivery

Polysaccharides constitute one of the most important families of biopolymers. Natural polysaccharide-based drug delivery systems are of constant interest to the scientific community due to their unique properties: biocompatibility, non-toxicity, biodegradability, and high availability. These promising biomaterials protect sensitive active agents and provide their controlled release in targeted sites. The application of natural polysaccharides as drug delivery systems is also intensively developed by Polish scientists. The present review focuses on case studies from the last few years authored or co-authored by research centers in Poland. A particular emphasis was placed on the diversity of the formulations in terms of the active substance carried, the drug delivery route, the composition of the material, and its preparation method.

Antibacterial peptide NZ2114-loaded hydrogel accelerates Staphylococcus aureus-infected wound healing

Wound infection caused by Staphylococcus aureus (S. aureus) is a great challenge which has caused significant burden and economic loss to the medical system. NZ2114, a plectasin-derived peptide, is an antibacterial agent for preventing and treating S. aureus infection, especially for methicillin-resistant S. aureus (MRSA) infection. Here, three-dimensional reticulated antimicrobial peptide (AMP) NZ2114 hydrogels were developed based on hydroxypropyl cellulose (HPC) and sodium alginate (SA); they displayed sustained and stable release properties (97.88 ± 1.79% and 91.1 ± 10.52% release rate in 72 h, respectively) and good short-term cytocompatibility and hemocompatibility. But the HPC-NZ2114 hydrogel had a smaller pore size (diameter 0.832 ± 0.420 μm vs. 3.912 ± 2.881 μm) and better mechanical properties than that of the SA-NZ2114 hydrogel. HPC/SA-NZ2114 hydrogels possess efficient antimicrobial activity in vitro and in vivo. In a full-thickness skin defect model, the wound closure of the 1.024 mg/g HPC-NZ2114 hydrogel group was superior to those of the SA-NZ2114 hydrogel and antibiotic groups on day 7. The HPC-NZ2114 hydrogel accelerated wound healing by reducing inflammation and promoting the production of vascular endothelial growth factor (VEGF), endothelial growth factor (EGF) and angiogenesis (CD31) through histological and immunohistochemistry evaluation. These data indicated that the HPC-NZ2114 hydrogel is an excellent candidate for S. aureus infection wound dressing. KEY POINTS: •NZ2114 hydrogels showed potential in vitro bactericidal activity against S. aureus •NZ2114 hydrogels could release continuously for 72 h and had good biocompatibility •NZ2114 hydrogels could effectively promote S. aureus-infected wound healing.

Multi-Responsive Optimization of Novel pH-Sensitive Hydrogel Beads Based on Basil Seed Mucilage, Alginate, and Magnetic Particles

Conventional drug delivery systems often cause side effects and gastric degradation. Novel drug delivery systems must be developed to decrease side effects and increase the efficacy of drug delivery. This research aimed to fabricate hydrogel beads for use as a drug delivery system based on basil seed mucilage (BSM), sodium alginate (SA), and magnetic particles (MPs). The Taguchi method and Grey relational analysis were used for the design and optimization of the hydrogel beads. Three factors, including BSM, SA, and MPs at four levels were designed by L-16 orthogonal arrays. BSM was the main factor influencing bead swelling, drug release rate at pH 7.4, and release of antioxidants at pH 1.2 and 7.4. In addition, SA and MPs mainly affected drug loading and drug release rate in acidic medium, respectively. Grey relational analysis indicated that the composition providing optimal overall properties was 0.2 vol% BSM, 0.8 vol% SA, and 2.25 vol% MPs. Based on the findings of this work, BSM/SA/MPs hydrogel beads have the potential to be used as a pH-sensitive alternative material for drug delivery in colon-specific systems.