2.6.2. Skin Tissue Regeneration
The skin, being the body’s largest vital organ, serves as a protective barrier against the external environment. While skin tissue possesses self-regenerating abilities, these capabilities significantly diminish in cases of full-thickness injuries, necessitating skin grafts or dressings
[68][227]. The process of cutaneous wound healing, essential for repairing damaged skin tissue, involves several intricate stages: hemostasis, inflammation, proliferation, and remodeling
[69][228]. Hemostasis, occurring immediately after injury, involves platelet aggregation and blood clotting. The inflammatory stage involves the presence of neutrophils and macrophages releasing cytokines at the wound site. During the proliferative phase, fibroblast differentiation leads to the initiation of re-epithelialization through the synthesis of the extracellular matrix. The final stage involves collagen synthesis and myofibroblast activity, facilitating tissue remodeling
[70][71][229,230]. These stages progress sequentially within a specific timeframe for complete healing.
Globally, various wound dressings have been developed to address epidermal damage. Traditional materials like bandages, cotton wool, lint, and gauze were historically utilized to absorb wound exudates, maintaining dryness to prevent bacterial infection
[71][72][230,231]. Given the complexities of wound healing, an ideal wound dressing should possess exceptional biocompatibility to enhance tissue regeneration
[73][232]. It should also enable gas exchange, shield the wound from microbial infections, absorb excess fluids without leakage, and be non-adherent and comfortable
[74][233]. As a result, novel materials meeting the aforementioned characteristics need to be developed. Amongst them, MgO-based nanomaterials have gained considerable researchers’ attention within the last decade, given the fact that magnesium oxide is considered to be biologically safe, capable of biodegradation, cost-effective, and environmentally friendly, holding significant promise for various biomedical applications
[75][234].
The primary impediment in the healing process of diabetic wounds is insufficient angiogenesis. Based on existing scientific reports, electrospun nanofiber membranes have demonstrated potential as wound dressings. To effectively address diabetic wounds, it is crucial for electrospun membranes to stimulate wound angiogenesis. Current strategies predominantly focus on employing pro-angiogenic growth factors to augment the angiogenic properties of these membranes. However, integrating growth factors into electrospun nanofibers and sustaining their activity long-term pose technical challenges. Taking the aforementioned into consideration, Liu and co-researchers
[29] introduced an electrospun membrane comprising polycaprolactone, gelatin, and magnesium oxide nanoparticles, releasing Mg
2+ ions to further promote angiogenesis. The as-prepared membranes encouraged human umbilical vein endothelial cell proliferation and enhanced vascular endothelial growth factor production in vitro. Implantation studies in a rat model reveal that the MgO-included membrane facilitated the early formation of robust blood vessels within a week post surgery, fostering enriched capillary networks within the degrading membrane over time.
2.7. Bioimaging Applications
Extensive research focuses on fluorescent nanoparticles to enable real-time bioimaging and tracking of biological processes at the nanoscale. These nanoparticles hold promise for advancing diagnostic tools and targeted drug release therapies. Metal oxide nanoparticles
[76][77][78][235,236,237] have gained attention as contrast agents in bioimaging, due to their room-temperature single-photon emission
[76][78][235,237], customizable optical properties
[79][238], and low toxicity. However, challenges persist in their application, such as low quantum efficiency and brightness
[77][78][236,237], propensity for agglomeration in cell culture media
[77][236], and dose-dependent cytotoxicity
[80][239].
For effective in vitro experiments, a fluorescent marker must absorb light above 500 nm and emit light beyond 600 nm to mitigate cell autofluorescence
[81][240]. In contrast, for in vivo experiments, emission in the near-infrared (NIR) range, between 700 and 900 nm, is crucial as it penetrates tissue over centimeters, unlike visible light, which travels mere microns
[82][241]. Magnesium oxide nanoparticles apart from being biocompatible and biodegradable as previously mentioned, are also intrinsically fluorescent
[83][242].
Taking the aforementioned into account, Rasheed and Sandhyarani
[84][243] conducted the synthesis of luminescent nanocrystals of magnesium oxide by introducing a very low amount of Cr
3+ as a dopant. The production of chromium-doped magnesium oxide nanocrystals involved the use of magnesium nitrate as the base material and chromic nitrate as the doping agent.
Additionally, in a study by Khalid and co-researchers
[83][242], the inherent and enduring fluorescent characteristics of magnesium oxide nanoparticles derived from naturally present chromium Cr
3+ and vanadium V
2+ ions were detailed. These properties encompassed a fluorescence spectrum spanning from the visible to the near-infrared range, enabling their potential utilization for real-time monitoring of live cells derived from both normal and cancerous tissues.
2.8. Drug Delivery Applications
Nanotechnology offers promising avenues in drug delivery, especially for combating terminal illnesses such as cancer
[85][86][87][245,246,247]. Previous studies have explored the utilization of nanostructures to administer drugs
[88][89][248,249], and nanoparticles have shown potential in targeting specific cell genes, particularly those in tumor cells. Nanostructures possess advantageous qualities, including a significant volume-to-surface ratio, customizable surface properties, and multifunctionality, making them appealing for drug delivery applications
[90][91][92][250,251,252].
Sabbagh and Muhamad
[93][253] employed acrylamide-based hydrogel systems for drug delivery, specifically for the release of Acyclovir from magnesium oxide nanocomposite hydrogel. Acyclovir was incorporated into the polymer through a soaking process, enabling the hydrogel system for use in vaginal drug delivery and subsequent release. An assessment of the chemical and physical properties of the reinforced hydrogels provided an analysis of the polymer’s morphological structure, swelling behavior, gel formation, and physical attributes. The drug release behavior in different mediums, PBS and SVF aqueous solutions, was examined, and the quantity of the released drug was determined using HPLC.