Addressing Antimicrobial Properties in Guided Tissue/Bone Regeneration Membrane: Enhancing Effectiveness in Periodontitis Treatment

Guided tissue regeneration (GTR) and guided bone regeneration (GBR) are the two surgical techniques generally used for periodontitis disease treatment. These techniques are based on a barrier membrane to direct the growth of new bone and gingival tissue at sites with insufficient volumes or dimensions of bone or gingiva for proper function, esthetics, or prosthetic restoration. Numerous studies have highlighted biocompatibility, space-creation, cell-blocking, bioactivity, and proper handling as essential characteristics of a membrane's performance. Given that bacterial infection is the primary cause of periodontitis, we strongly believe that addressing the antimicrobial properties of these membranes is of utmost importance. Indeed, the absence of effective inhibition of periodontal pathogens has been recognized as a primary factor contributing to the failure of GTR/GBR membranes. Therefore, we suggest considering antimicrobial properties as one of the key factors in the design of GTR/GBR membranes. Antibiotics are potent medications frequently administered systemically to combat microbes and mitigate bacterial infections. Nevertheless, the excessive use of antibiotics has resulted in a surge in bacterial resistance. To overcome this challenge, alternative antibacterial substances have been developed. In this review, we explore the utilization of alternative substances with antimicrobial properties for topical application in membranes. The use of antibacterial nanoparticles, phytochemical compounds, and antimicrobial peptides in this context was investigated. By carefully selecting and integrating antimicrobial agents into GTR/GBR membranes, we can significantly enhance their effectiveness in combating periodontitis. These antibacterial substances not only act as barriers against pathogenic bacteria but also promote the process of periodontal healing.

Determining the cytotoxicity of the Minimum Inhibitory Concentration (MIC) of silver and zinc oxide nanoparticles in ESBL and carbapenemase producing Proteus mirabilis isolated from clinical samples in Shiraz, Southwest Iran

OBJECTIVE

Proteus mirabilis is related to serious infections. The present study was designed to investigate the minimum inhibitory concentration (MIC) of silver nanoparticles (AgNPs) and zinc oxide nanoparticles (ZnONPs) and cytotoxicity among P. mirabilis isolates recovered from clinical samples in Shiraz.

RESULTS

A total of 100 P. mirabilis isolates were screened by biochemical tests and polymerase chain reaction (PCR). Also, 25 (25%) and 7 (7%) isolates were positive for extended-spectrum beta-lactamase (ESBLs) and carbapenemase, respectively. Synthesized nanoparticles were characterized by UV-vis spectrum, X-ray diffraction (XRD), and electron microscopy. The average size of AgNPs and ZnONPs in the present study is 48 and < 70 nm, respectively. The MIC and the MBC of the ZnONPs were in the range of 31.25 µg/ml and 62.5 µg/mL, respectively. Also, for AgNPs, the MIC and the MBC were in the range of 7.8 µg/mL and 15.6 µg/mL, respectively. MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay in a primary culture of fibroblast L929 cells for this MIC indicated biocompatibility and low cytotoxicity of Ag NPs and for ZnONPs indicated significant cytotoxicity. Also, a MIC of AgNPs can be used as a therapeutic concentration without the effect of cytotoxicity in human cells.

Comparison capacity of collagen hydrogel, mix-powder and in situ hydroxyapatite/collagen hydrogelscaffolds with and without mesenchymal stem cells and platelet-rich plasma in regeneration of critical sized bone defect in a rabbit animal model

The aim of this study was to investigate the effect of developed collagen (Co) hydrogel (CH), powder-mixed hydroxyapatite/collagen (HA/Co) hydrogel and in situ synthesized HA/Co (In/HA/Co) hydrogel with or without mesenchymal stem cell (MSC) and platelet-rich plasma (PRP) on the regeneration of full-thickness critical size bone defect in the rabbit animal model. In the first step of this study, the scaffolds were synthesized and characterized using FTIR spectroscopy, X-ray diffraction, and scanning electron microcopy. In the second step or animal study, the radial bone defects were filled with the synthesized scaffolds with and without MSC and PRP. One hundred sixty one year-old New Zealand white male rabbits were randomly divided in 16 groups of 10 rabbits including control with bone defect without treatment, In/HA/Co, HA/Co, CH, PRP, MSC, CH + PRP, HA/Co, In/HA/Co + PRP, HA/Co + PRP, CH + MSC, In/HA/Co + MSC, HA/Co + MSC, CH + PRP + MSC, In/HA/Co + PRP + MSC, and HA/Co + PRP + MSC. The created defects were filled using the constructed scaffolds alone or seeded with MSCs, with and without PRP injection. The treatments were assessed using histopathological, immunohistochemical and rediographical analysis on days 14, 28, 42, 56 post-treatment. The plate-like HA particles were distributed homogeneously in the in situ HA/Co scaffold compared to the HA/Co scaffold and had a similar structure to bone with carbonated plate-like HA particles and nanofibrilated Co matrix. In situ HA/Co nanocomposite seeded with MSC and enriched by PRP can accelerate bone regeneration resulted from osteoblastic production of osteocalcin protein. Therefore, in situ HA/Co hydrogel seeded with MSC and PRP can be a new approach for bone tissue engineering.