Flow Behavior and Drug Release Study of Injectable Pluronic F-127 Hydrogels containing Bioactive Glass and Carbon-Based Nanopowders

Synthesis and characterization of injectable thermosensitive hydrogel based on Pluronic-grafted silk fibroin copolymer containing hydroxyapatite nanoparticles as potential for bone tissue engineering

Injectable hydrogels are promising for bone tissue engineering due to their minimally invasive application and adaptability to irregular defects. This study presents the development of pluronic grafted silk fibroin (PF-127-g-SF), a temperature-sensitive graft copolymer synthesized from SF and modified PF-127 via a carbodiimide coupling reaction. The PF-127-g-SF copolymer exhibited a higher sol-gel transition temperature (34 °C at 16 % w/v) compared to PF-127 (23 °C), making it suitable for injectable applications. It also showed improved flexibility and strength, with a yielding point increase from <10 % to nearly 30 %. Unlike PF-127 gel, which degrades within 72 h in aqueous media, the PF-127-g-SF copolymer maintained a stable gel structure for over two weeks due to its robust crosslinked hydrogel network. Incorporating hydroxyapatite nanoparticles (n-HA) into the hydrogel reduced pore size and decreased swelling and degradation rates, extending structural stability to four weeks. Increasing n-HA concentration from 0 % to 20 % reduced porosity from 80 % to 66 %. Rheological studies indicated that n-HA enhanced the scaffold's strength and mechanical properties without altering gelation temperature. Cellular studies with MG-63 cells showed that n-HA concentration influenced cell viability and mineralization, highlighting the scaffold's potential in bone tissue engineering.

The effects of bioactive glass hydrogel coated with hyaluronic acid-Pluronic F-127 conjugates containing silver nanoparticles for accelerating of infected wounds healing

Antimicrobial resistance has forced researchers to produce new dressings for the treatment of infected wounds. Tissue engineering based on biomaterials is used to accelerate the wound healing process. The purpose of this study was to examine the effects of bioactive glass (BG) hydrogel coated with hyaluronic acid (HA)-Pluronic F-127 (PLF-127) conjugates containing silver nanoparticles (AgNPs) for healing the infected wounds. HA/BG, PL&HA/BG and PL&HA/BG-AgNPs formulations were designed and their properties were evaluated for application in the wound healing process. Safety and antibacterial properties of formulations were also evaluated. These were applied for the treatment of infected wounds and their efficiencies were assessed by measuring wound contraction, total bacterial count, pathological parameters and the expression of positive cells of cyclin-D1, c-Myc, WNT-1, B-Catenin, and COL-1A. The synthesized thermally reversible hydrogels demonstrated sol-gel transition, indicating the gels' potential as injectable hydrogels. These exhibited antibacterial properties and safety. The PL&HA/BG-AgNPs, PL&HA/BG and HA/BG hydrogels showed greatest wound healing activities, respectively and could compete with Polysporin® due to their effects on total bacterial count and modulation in increasing the expressions of B-Catenin, COL-1A, cyclin-D1 and c-Myc. In sum, PL&HA/BG-AgNP hydrogels are good candidate for accelerating the wound healing process and as alternatives for antibiotics in the treatment of infected wounds.

In vitro cytotoxicity of magnetic-fluorescent bioactive glasses on SaOS-2, MC3T3-E1, BJ fibroblast cells, their hemolytic activity, and sorafenib release behavior

In the study, the fabrication of superparamagnetic-fluorescent bioactive glasses in the form of the particle, nanofiber, and 3D scaffolds was performed by including maghemite (γ-Fe2O3) nanoparticles and photoluminescent rare earth element ions (Eu3+, Gd3+, and Yb3+) using sol-gel, electrospinning, and robocasting techniques, respectively. The in vitro cytotoxicity of the magnetic-fluorescent bioactive glasses on osteosarcoma SaOS-2, pre-osteoblast MC3T3-E1, and BJ fibroblast cells, as well as their hemolytic activity and sorafenib tosylate loading and release behavior, were investigated. The cytotoxicity of the bioactive glass samples was tested using the MTT assay. Additionally, the alkaline phosphatase activity of the studied glasses was examined as a function of time. The mineralization behavior of the pre-osteoblast cell-seeded glass samples was analyzed using Alizarin red S staining. Results revealed that the in vitro cytotoxicity of the studied bioactive glasses in the form of particles and nanofibers depended on the sample concentration, whereas in the case of the 3D scaffolds, no cytotoxic response was observed on the osteosarcoma, pre-osteoblast, and fibroblast cells. Similarly, particle and nanofiber-based glass samples induced dose-dependent hemolysis on red blood cells. Drug loading rates were much lower for the 3D scaffolds compared to the particle and nanofiber-based samples. Drug release rates ranged from 25 % to 90 %, depending on the bioactive glass morphology and the pH of the release medium. It was concluded that the studied bioactive glasses have the potential to be used in tissue engineering applications and cancer therapy.

Effect of small amounts of akaganeite (β-FeOOH) nanorods on the gelation, phase behaviour and injectability of thermoresponsive Pluronic F127

Pluronic F127 (PF127) is a copolymer with an amphiphilic nature and can self-assemble to form micelles and, beyond 20% (w/v), form a thermoresponsive physical gel state. However, they are mechanically weak and easily dissolve in physiological environments, which limits their use in load-bearing in specific biomedical applications. Therefore, we propose a pluronic-based hydrogel with enhanced stability by incorporating small amounts of paramagnetic nanorods, akaganeite (β-FeOOH) nanorods (NRs) of aspect ratio ∼7, with PF127. Due to their weak magnetic properties, β-FeOOH NRs have been used as a precursor for preparing stable iron-oxide states (e.g., hematite and magnetite), and the studies on β-FeOOH NRs to be used as a primary component in hydrogels are at the nascent stage. Here we report a method to synthesize β-FeOOH NRs on a gram scale using a simple sol-gel process and characterize the NRs with various techniques. A phase diagram and thermoresponsive behaviour based on rheological experiments and visual observations are proposed for 20% (w/v) PF127 with low concentrations (0.1-1.0% (w/v)) of β-FeOOH NRs. We observe a unique non-monotonous behaviour in the gel network represented by various rheological parameters like storage modulus, yield stress, fragility, high-frequency modulus plateau, and characteristic relaxation time as a function of nanorod concentration. A plausible physical mechanism is proposed to fundamentally understand the observed phase behaviour in the composite gels. These gels show thermoresponsiveness and enhanced injectability, and could find applications in tissue engineering and drug delivery.

Tubular nanomaterials for bone tissue engineering

Nanomaterial composition, morphology, and mechanical performance are critical parameters for tissue engineering. Within this rapidly expanding space, tubular nanomaterials (TNs), including carbon nanotubes (CNTs), titanium oxide nanotubes (TNTs), halloysite nanotubes (HNTs), silica nanotubes (SiNTs), and hydroxyapatite nanotubes (HANTs) have shown significant potential across a broad range of applications due to their high surface area, versatile surface chemistry, well-defined mechanical properties, excellent biocompatibility, and monodispersity. These include drug delivery vectors, imaging contrast agents, and scaffolds for bone tissue engineering. This review is centered on the recent developments in TN-based biomaterials for structural tissue engineering, with a strong focus on bone tissue regeneration. It includes a detailed literature review on TN-based orthopedic coatings for metallic implants and composite scaffolds to enhance in vivo bone regeneration.

Preparation, thermal response mechanisms and biomedical applications of thermosensitive hydrogels for drug delivery

INTRODUCTION

Drug treatment is one of the main ways of coping with disease today. For the disadvantages of drug management, thermosensitive hydrogel is used as a countermeasure, which can realize the simple sustained release of drugs and the controlled release of drugs in complex physiological environments.

AREAS COVERED

This paper talks about thermosensitive hydrogels that can be used as drug carriers. The common preparation materials, material forms, thermal response mechanisms, characteristics of thermosensitive hydrogels for drug release and main disease treatment applications are reviewed.

EXPERT OPINION

When thermosensitive hydrogels are used as drug loading and delivery platforms, desired drug release patterns and release profiles can be tailored by selecting raw materials, thermal response mechanisms, and material forms. The properties of hydrogels prepared from synthetic polymers will be more stable than natural polymers. Integrating multiple thermosensitive mechanisms or different kinds of thermosensitive mechanisms on the same hydrogel is expected to realize the spatiotemporal differential delivery of multiple drugs under temperature stimulation. The industrial transformation of thermosensitive hydrogels as drug delivery platforms needs to meet some important conditions.

Injectable nanocomposite hydrogels as an emerging platform for biomedical applications: A review

Hydrogels have attracted much attention for biomedical and pharmaceutical applications due to the similarity of their biomimetic structure to the extracellular matrix of natural living tissues, tunable soft porous microarchitecture, superb biomechanical properties, proper biocompatibility, etc. Injectable hydrogels are an exciting type of hydrogels that can be easily injected into the target sites using needles or catheters in a minimally invasive manner. The more comfortable use, less pain, faster recovery period, lower costs, and fewer side effects make injectable hydrogels more attractive to both patients and clinicians in comparison to non-injectable hydrogels. However, it is difficult to achieve an ideal injectable hydrogel using just a single material (i.e., polymer). This challenge can be overcome by incorporating nanofillers into the polymeric matrix to engineer injectable nanocomposite hydrogels with combined or synergistic properties gained from the constituents. This work aims to critically review injectable nanocomposite hydrogels, their preparation methods, properties, functionalities, and versatile biomedical and pharmaceutical applications such as tissue engineering, drug delivery, and cancer labeling and therapy. The most common natural and synthetic polymers as matrices together with the most popular nanomaterials as reinforcements, including nanoceramics, carbon-based nanostructures, metallic nanomaterials, and various nanosized polymeric materials, are highlighted in this review.

Mesoporous Properties of Bioactive Glass Synthesized by Spray Pyrolysis with Various Polyethylene Glycol and Acid Additions

Mesoporous bioactive glass (MBG) has a high specific surface area, promoting the reaction area, thereby improving the bioactivity; thus, MBG is currently gaining popularity in the biomaterial field. Spray pyrolysis (SP) is a one-pot process that has the advantages of shorter process time and better particle bioactivity, therefore, MBG was prepared by SP process with various polyethylene glycol (PEG, molecular weight ranged from 2000-12,000) and acid (HCl and CH3COOH) additions. In vitro bioactivity and mesoporous properties of the so-obtained MBG were investigated. The experimental results showed that all the MBG exhibited amorphous and mesoporous structure. Increasing the molecular weight of PEG can improve the mesoporous structure and bioactivity of MBG. Whereas optimized MBG was prepared with suitable concentration of PEG and CH3COOH. In the present work, MBG synthesized via spray pyrolysis by adding 5 g of PEG with a molecular weight of 12,000 and 50 mL of CH3COOH exhibited the best in vitro bioactivity and mesoporous structure.

In situ formation of injectable hydrogels for chronic wound healing

Hydrogels have been widely used in wound healing treatment over the past decade.