Novel multifunctional dexamethasone carbon dots synthesized using the one-pot green method for anti-inflammatory, osteogenesis, and osteoimmunomodulatory in bone regeneration

The applications of carbon dots in oral health: A scoping review

OBJECTIVES

This scoping review aims to provide an overview of the research and potential applications of carbon dots (CDs) for oral health purposes.

DESIGN

Systematic literature searches were performed on PubMed and Web of Science databases (up to February 2023). Two co-authors selected the published works independently and extracted the data in accordance with the PRISMA statement. Studies with the application of CDs for oral health purposes were included.

RESULTS

Among 152 articles, 19 articles were finally selected. Eight studies investigated the anti-microbial effects of CDs against, for example, oral pathogens, eight studies explored the applicability of CDs in relation to oral cancer, and three studies investigated CDs in relation to cell differentiation and tissue regeneration in oral health. The studies showed the promising potential of CDs in oral health, particularly for inducing bacterial killing by increasing reactive oxygen species, killing oral cancer cells via photodynamic therapeutic effects, and inducing dental pulp and periodontal bone regeneration.

CONCLUSION

The findings show that CDs have the potential to be utilized in the future for various oral health purposes. Besides, these results underline the broad-spectrum applicability of CDs, crossing the borders of oral health.

3D Molybdenum Disulfide Nanospheres Loaded with Metformin to Enhance SCPP Scaffolds for Bone Regeneration

Conventional strontium-doped calcium polyphosphate (SCPP) ceramics have attracted a lot of attention due to good cytocompatibility and controlled degradation. However, their poor mechanical strength, brittleness, and difficulty in eliminating unavoidable postoperative inflammation and bacterial infections in practical applications limit their further clinical application. In this study, carboxylated molybdenum disulfide nanospheres (MoS2-COOH) were first prepared via a one-step hydrothermal method. The optimal doping concentration of MoS2-COOH was then incorporated into SCPP to overcome its poor mechanical strength. To further enhance the anti-inflammatory properties of scaffolds, metformin (MET) was loaded onto MoS2-COOH through covalent bond cross-linking (MoS2-MET). Then MoS2-MET was doped into SCPP (SCPP/MoS2-MET) according to the previously obtained concentration, resulting in the controlled and sustained release of MET from the SCPP/MoS2-MET scaffolds for 21 days in vitro. The SCPP/MoS2-MET scaffolds were shown to have good biological activity in vitro to promote stem cell proliferation and the potential to promote mineralization in vitro. It also showed good osteoimmunomodulatory activity could reduce the expression of proinflammatory factors and effectively induce the differentiation of BMSCs under inflammatory conditions, upregulating the expression of relevant osteoblastic cytokines. In addition, SCPP/MoS2-MET scaffolds could effectively inhibit Staphylococcus aureus and Escherichia coli. In vivo experiments also demonstrated better osteogenic potential of SCPP/MoS2-MET scaffolds compared with the other scaffold-samples. Thus, the introduction of carboxylated molybdenum disulfide nanospheres is a promising approach to improve the properties of SCPP and may provide a new modification strategy for inert ceramic scaffolds and the construction of multifunctional composite scaffolds for bone tissue engineering.

A photocrosslinked methacrylated carboxymethyl chitosan/oxidized locust bean gum double network hydrogel for cartilage repair

Repairing articular cartilage defects is a great challenge due to the poor self-regenerative capability of cartilage. Inspired by active substances found in the natural cartilage extracellular matrix, we used methacrylated carboxymethyl chitosan (MA-CMCS) and oxidized locust bean gum (OLBG) as the hydrogel backbone, and prepared a photocrosslinked dual network hydrogel containing allicin and decellularized cartilage powder (DCP). The rheological, swelling and water retention capacities of MA-CMCS@OLBG-Allicin/DCP (MCOAC) hydrogels were investigated to confirm the successful preparation of hydrogels suitable for cartilage repair. The MCOAC hydrogels showed good antibacterial ability to kill S. aureus and E. coli and anti-inflammatory properties due to the introduction of allicin. Furthermore, MA-CMCS@OLBG-Allicin/DCP hydrogels presented good cytocompatibility due to the addition of DCP, which could promote chondrocyte proliferation and promote the differentiation of BMSCs to chondrocytes. Further studies in vivo demonstrated that the DCP-contained MCOAC hydrogel exhibited superior performance in promoting cartilage tissue growth and wound healing in articular cartilage defects. Thus, the MCOAC hydrogel is a promising cartilage repair hydrogel with potential for clinical use.

Carbonized Tetracycline: a new class of nanomaterial with tuneable antioxidant, reduced cytotoxicity, immunomodulatory, and osteogenic properties

Tetracycline (TET), a broad-spectrum antibiotic, also possesses different non-antibiotic activities such as inhibition of metalloproteinase (MMP), anti-inflammatory, antioxidant, high bone affinity, etc. However, the comparatively low efficacy of these non-antibiotic properties along with adverse effects such as hyperpigmentation, phototoxicity, long-term skeletal retention, etc. have not helped their broad utilization similar to their use as an antibiotic. In a unique attempt to improve the non-antibiotic properties while reducing the adverse effects, we converted the TET to nano-carbons through partial carbonization. After sorting out two water-dispersible C-TETs (C-TET HT - hydrothermal and C-TET HP - hot plate) based on their improved antioxidant activity, they have been characterized through a host of analytical techniques that showed distinct differences in morphology, size, shape, and surface functionality. Excitingly, the C-TET HT and C-TET HP have shown differential biological activity in a dosage and time-dependent manner in terms of cytotoxicity, immunomodulation, and osteogenic activity that was found to be associated with their carbonized parameters. Overall, the carbonized nano-drugs, C-TET HT and C-TET HP have presented substantial early promises on their non-antibiotic properties that could be further explored to develop into some effective therapeutics.

Multifunctional xyloglucan-containing electrospun nanofibrous dressings for accelerating infected wound healing

Preventing wound infection is a major challenge in biomedicine. Conventional wound dressings often have poor moisturizing and antimicrobial properties unfavorable for wound healing. In this study, we prepared a multifunctional electrospun nanofiber dressing (PCQX-M) containing xyloglucan, quaternized chitosan, Polyvinyl alcohol, and collagen. By applying the concept of wet healing, xyloglucan and quaternized chitosan polysaccharides with excellent water solubility were employed to improve the absorption and moisturizing properties and maintain a moist microenvironment for the wound healing process. PCQX-M demonstrated high mechanical, thermodynamic, and biocompatible properties, providing suitable healing conditions for wounds. In addition, PCQX-M showed exceptional antibacterial properties and a potential inhibitory effect on the growth of microorganisms in infected wounds. More intriguingly, the restorative healing effect was investigated on a mouse model of whole skin injury infected with Staphylococcus aureus. Wound healing, collagen deposition, and immunofluorescence results showed that PCQX-M significantly promoted cell proliferation and angiogenesis at the injury site and facilitated the healing of the infected wound. Our study suggests that PCQX-M has excellent potential for clinical application in infected wound healing.

Design of carbon dots for bioimaging and behavior regulation of stem cells

Carbon dots (CDs) have been widely used in bioimaging, biosensing and biotherapy because of their good biocompatibility, optical properties and stability. In this review, we comprehensively summarize the research on CDs in terms of synthesis methods, optical properties and biotoxicity. We describe and envisage the directions for CDs application in stem cell imaging and differentiation, with the aim of stimulating the design of future related CDs. We used 'carbon dots', 'stem cells', 'cell imaging', 'cell differentiation' and 'fate control' as keywords to search for important articles. The Web of Science database was used to extract vital information from a total of 357 papers, 126 review articles and 231 article proceedings within 12 years (2011-2022).

Carbon Dots for the Treatment of Inflammatory Diseases: An Appraisal of In Vitro and In Vivo Studies

In recent decades, several studies demonstrating various applications of carbon dots (C-dots), including metal sensing, bioimaging, pH sensing, and antimicrobial activities, have been published. Recent developments have shifted this trend toward biomedical applications that target various biomarkers relevant to chronic diseases. However, relevant developments and research results regarding the anti-inflammatory properties of C-dots against inflammation-associated diseases have not been systematically reviewed. Hence, this review discusses the anti-inflammatory effects of C-dots in in vivo and in vitro models of LPS-induced inflammation, gout, cartilage tissue engineering, drug-induced inflammation, spinal cord injury, wound healing, liver diseases, stomach cancer, gastric ulcers, acute kidney and lung injury, psoriasis, fever or hypothermia, and bone tissue regeneration. The compiled studies demonstrate the promising potential of C-dots as anti-inflammatory agents for the development of new drugs.

Carbon dots with tissue engineering and regenerative medicine applications

Carbon dots (CDs) with unique physicochemical features such as exceptional biocompatibility, low cost, eco-friendliness, abundant functional groups (e.g., amino, hydroxyl, and carboxyl), high stability, and electron mobility have been broadly investigated in nano- and biomedicine. In addition, the controlled architecture, tunable fluorescence emission/excitation, light-emitting potential, high photostability, high water solubility, low cytotoxicity, and biodegradability make these carbon-based nanomaterials suitable for tissue engineering and regenerative medicine (TE-RM) purposes. However, there are still limited pre- and clinical assessments, because of some important challenges such as the scaffold inconsistency and non-biodegradability in addition to the lack of non-invasive methods to monitor tissue regeneration after implantation. In addition, the eco-friendly synthesis of CDs exhibited some important advantages such as environmentally friendly properties, low cost, and simplicity compared to the conventional synthesis techniques. Several CD-based nanosystems have been designed with stable photoluminescence, high-resolution imaging of live cells, excellent biocompatibility, fluorescence properties, and low cytotoxicity, which make them promising candidates for TE-RM purposes. Combining attractive fluorescence properties, CDs have shown great potential for cell culture and other biomedical applications. Herein, recent advancements and new discoveries of CDs in TE-RM are considered, focusing on challenges and future perspectives.

Recent advances in carbon dots: synthesis and applications in bone tissue engineering

Bone tissue engineering (BTE), based on the perfect combination of seed cells, scaffold materials and growth factors, has shown unparalleled potential in the treatment of bone defects and related diseases. As the site of cell attachment, proliferation and differentiation, scaffolds composed of biomaterials play a crucial role in BTE. Over the past years, carbon dots (CDs), a new type of carbon-based nanomaterial, have attracted extensive research attention due to their good biocompatibility, unique optical properties, and abundant functional groups. This paper reviews recent research progress in the use of CDs in the field of BTE. Firstly, different preparation methods of CDs are summarized. Then, the properties and categories of CDs applied in BTE are described in detail. Subsequently, the applications of CDs in BTE, including osteogenesis, fluorescence tracing, phototherapy and antibacterial activity, are presented. Finally, the challenges and future perspectives of CDs in BTE are briefly discussed to give a comprehensive picture of CDs. This review provides a theoretical basis and advanced design strategies for the application of CDs in BTE.