Chitosan coated graphene oxide incorporated sodium alginate hydrogel beads for the controlled release of amoxicillin

A review of sodium alginate-based hydrogels: Structure, mechanisms, applications, and perspectives

With the global emphasis on green and sustainable development, sodium alginate-based hydrogels (SAHs), as a renewable and biocompatible environmental material, have garnered widespread attention for their research and application. This review summarizes the latest advancements in the study of SAHs, thoroughly discussing their structural characteristics, formation mechanisms, and current applications in various fields, as well as prospects for future development. Initially, the chemical structure of SA and the network structure of hydrogels are introduced, and the impact of factors such as molecular weight, crosslinking density, and environmental conditions on the hydrogel structure is explored. Subsequently, the formation mechanisms of SAHs, including physical and chemical crosslinking, are detailed. Furthermore, a systematic review of the applications of SAHs in tissue engineering, drug delivery, medical dressings, wastewater treatment, strain sensor, and food science is provided. Finally, future research directions for SAHs are outlined. This work not only offers researchers a comprehensive framework for the study of SAHs but also provides significant theoretical and experimental foundations for the development of new hydrogel materials.

Graphene oxide/chitosan hydrogels for removal of antibiotics

Antibiotic contamination in aquatic environments is a growing concern, posing risks to public health and ecosystems. To address this issue, advanced materials like graphene oxide (GO) and chitosan-based hydrogels are being extensively explored for their ability to effectively remove antibiotics from wastewater, owing to their distinct characteristics and synergistic benefits. This review comprehensively examines the synthesis, characterization, and applications of GO/chitosan hydrogels in addressing antibiotic pollution. The synthesis methods, including solution casting, crosslinking, and in situ polymerization, are discussed for their simplicity and scalability. The hydrogels' key properties, such as porosity, surface area, and mechanical strength, are essential for their efficient adsorption capabilities. Adsorption mechanisms, including electrostatic interactions, π-π stacking, hydrogen bonding, and surface functional groups, enable these hydrogels to achieve high adsorption capacities. Notable examples include rGO@ZIF-67@CS hydrogels, which achieved higher adsorption capacities of 1685.26 mg·g-1 for tetracycline at pH 4 and 1890.32 mg·g-1 for norfloxacin at pH 5, while the sulfonated CMC/GO-GCC composite hydrogel achieved 312.28 mg·g-1 for sulfamethoxazole at 298 K. Moreover, high adsorption efficiencies of 90.42% with GO-CTS and 97.06% were achieved using AGO-CTS hydrogel for diclofenac adsorption. The review also highlights the practical applications of these hydrogels in wastewater treatment, comparing their performance with other adsorbents and addressing challenges such as scalability and regeneration. Finally, the review explores future research directions to enhance the effectiveness and sustainability of GO/chitosan hydrogels, emphasizing their potential as scalable, eco-friendly solutions for antibiotic removal from water.

Vibration-assisted Microbead Production: A New Frontier for Biocompatible Surfaces

The encapsulation of active pharmaceutical ingredients (APIs) in microbeads is an essential step in drug delivery; however, it is also inherently associated with the need to control particle size and drug release profiles. Nevertheless, most conventional methods of microencapsulation fail to provide consistent results. A new method called vibration-assisted microbead coating is a novel unified technique utilizing mechanical vibrations to enable the controlled, uniform coating of microbeads on APIs. This chapter discusses the technology of vibration-assisted encapsulation performed by the authors through microbead formation and the physical activity of coating APIs. This chapter focuses on achieving uniform control of the final coated surface of the API, microbead shape, size, and loading through vibration parameters. Additionally, this chapter discusses the biocompatibility and stability of the final coated surface. This new means of encapsulation has high potential for drug delivery. This method reduces most of the traditional challenges of encapsulation, if not eliminates them, and is more reliable. Based on the abovementioned findings, the authors propose the following main areas for their further work: optimisation of vibration parameters for various APIs, research into the long-term stability of the loading–release profile, and possible use of the technique in targeted drug delivery.

Construction and characterization of sodium alginate/polyvinyl alcohol double-network hydrogel beads with surfactant-tailored adsorption capabilities for efficient tetracycline hydrochloride removal

The extensive use of tetracycline (TC) for disease control and the residuals in wastewater has resulted in the spread and accumulation of antibiotic resistance genes, posing a severe threat to the human health and environmental safety. To solve this problem, a series of double-network hydrogel beads based on sodium alginate and polyvinyl alcohol were constructed with the introduction of various surfactants to modulate the morphology. The results showed that the introduction of surfactants can modulate the surface morphology and internal structure, which can also regulate the adsorption ability of the hydrogel beads. The SDS-B beads with SDS as surfactant exhibited highest adsorption efficiency for removal of TC with a maximum adsorption capacity up to 121.6 mg/g, which possessed a resistance to various cations and humic acid. The adsorption mechanism revealed that the superior adsorption performance of the hydrogel beads was primarily attributed to hydrogen bonding, electrostatic attraction, and π-π EDA interactions. Adsorption kinetics demonstrated that the pseudo-second-order model fitted the adsorption process well and adsorption isotherm showed the adsorption of TC occurred through both chemical and physical interactions. Moreover, the adsorption efficiency remained approximately 87.5 % after three adsorption-desorption cycles, which may have potential application and practical value in TC adsorption.

Droplet Microfluidics Powered Hydrogel Microparticles for Stem Cell-Mediated Biomedical Applications

Stem cell-related therapeutic technologies have garnered significant attention of the research community for their multi-faceted applications. To promote the therapeutic effects of stem cells, the strategies for cell microencapsulation in hydrogel microparticles have been widely explored, as the hydrogel microparticles have the potential to facilitate oxygen diffusion and nutrient transport alongside their ability to promote crucial cell-cell and cell-matrix interactions. Despite their significant promise, there is an acute shortage of automated, standardized, and reproducible platforms to further stem cell-related research. Microfluidics offers an intriguing platform to produce stem cell-laden hydrogel microparticles (SCHMs) owing to its ability to manipulate the fluids at the micrometer scale as well as precisely control the structure and composition of microparticles. In this review, the typical biomaterials and crosslinking methods for microfluidic encapsulation of stem cells as well as the progress in droplet-based microfluidics for the fabrication of SCHMs are outlined. Moreover, the important biomedical applications of SCHMs are highlighted, including regenerative medicine, tissue engineering, scale-up production of stem cells, and microenvironmental simulation for fundamental cell studies. Overall, microfluidics holds tremendous potential for enabling the production of diverse hydrogel microparticles and is worthy for various stem cell-related biomedical applications.

Photothermal Hydrogel Composites Featuring G4-Carbon Nanomaterial Networks for Staphylococcus aureus Inhibition

Microbial infections represent a significant health risk, often leading to severe complications and, in some cases, even fatalities. As a result, there is an urgent need to explore innovative drug delivery systems and alternative therapeutic techniques. The photothermal therapy has emerged as a promising antibacterial approach and is the focus of this study. Herein, we report the successful synthesis of two distinct supramolecular composite hydrogels by incorporating graphene oxide (GO) and single-walled carbon nanotubes (SWNTs) into guanosine quadruplex (G4) based hydrogels containing covalently bound β-cyclodextrin (β-CD). The G4 matrix was synthesized through a two-step process, establishing a robust network between G4 and β-CDs, followed by the encapsulation of either GO or SWNTs. Comprehensive characterization of these composite hydrogels were conducted using analytical techniques, including circular dichroism, Raman spectroscopy, rheological investigations, X-ray diffraction, and scanning electron microscopy. A notable discovery from the conducted research is the differential photothermal responses exhibited by the hydrogels when exposed to near-infrared laser irradiation. Specifically, SWNT-based hydrogels demonstrated superior photothermal performance, achieving a remarkable temperature increase of up to 52 °C, in contrast to GO-based hydrogels, which reached a maximum of 34 °C. These composite hydrogels showed good cytotoxicity evaluation results and displayed synergistic antibacterial activity against Staphylococcus aureus, positioning them as promising candidates for antibacterial photothermic platforms, particularly in the context of wound treatment. This study offers a valuable contribution to the development of advanced and combined therapeutic strategies for combating microbial infections and highlights the potential of carbon nanomaterial-enhanced supramolecular hydrogels in photothermal therapy applications.