ABSTRACT
In recent years, due to a better understanding of the caries pathology and advances in dental materials, the utilization of non-invasive and minimally invasive techniques that delay/obviate the need for traditional restorations has started gaining momentum. This literature review focuses on some of these approaches, including fluoride varnish, silver diamine fluoride, resin sealants, resin infiltration, chemomechanical caries removal and atraumatic restorative treatment, in the context of their chemistries, indications for use, clinical efficacy, factors determining efficacy and limitations. Additionally, we discuss strategies currently being explored to enhance the antimicrobial properties of these treatment modalities to expand the scope of their application.
ABSTRACT
Porphyromonas gingivalis adherence to Streptococcus gordonii is a crucial initial event that facilitates the colonization of P. gingivalis, a key pathogen in periodontal disease. As such, blocking these early interactions may present a potential avenue to limit P. gingivalis colonization. Nanoparticles encapsulating a synthetic peptide BAR (BAR-encapsulated NPs) inhibit P. gingivalis/S. gordonii biofilm formation 1.8-fold more potently relative to free BAR. However, BAR-encapsulated NPs, like many orally delivered formulations, may benefit from a strategy that improves their retention in an open flow environment. Here, we sought to enhance the efficacy of BAR-encapsulated NPs by modifying their surfaces with coaggregation factor A (CafA), a fimbrial protein expressed by the early colonizer, Actinomyces oris. We demonstrate that the targeting moiety, CafA, enhances NP binding and exhibits specificity of adherence to S. gordonii, relative to other oral bacterial species. Furthermore, CafA-modified NPs release inhibitory concentrations of BAR for 12 h, a time frame relevant to oral dosage form delivery. Lastly, CafA-modified NPs potently inhibit P. gingivalis/S. gordonii biofilm formation for up to 12 h and are non-toxic at therapeutically-relevant concentrations. These results suggest that CafA-modified NPs represent a novel and efficacious delivery vehicle for localized, targeted delivery of BAR to P. gingivalis preferred niches.
ABSTRACT
Adipose-derived stem cells (ASCs) are a widely investigated type of mesenchymal stem cells with great potential for musculoskeletal regeneration. However, the use of ASCs is complicated by their cellular heterogeneity, which exists at both the population and single-cell levels. This study demonstrates a live-cell assay to investigate gene expression in ASCs undergoing osteogenesis using fluorescently tagged DNA hybridization probes called molecular beacons. A molecular beacon was designed to target the mRNA sequence for alkaline phosphatase (ALPL), a gene characteristically expressed during early osteogenesis. The percentage of cells expressing this gene in a population was monitored daily to quantify the uniformity of the differentiation process. Differentiating ASC populations were repeatedly measured in a nondestructive fashion over a 10-day period to obtain temporal gene expression data. Results showed consistent expression patterns for the investigated osteogenic genes in response to induction medium. Peak signal level, indicating when the most cells expressed ALPL at once, was observed on days 3-5. The differentiation response of sample populations was generally uniform when assessed on a well-by-well basis over time. The expression of alkaline phosphatase is consistent with previous studies of osteogenic differentiation, suggesting that molecular beacons are a viable means of monitoring the spatiotemporal gene expression of live, differentiating ASCs.
Subject(s)
Adipose Tissue/cytology , Cell Differentiation/genetics , Gene Expression Regulation , Osteogenesis/genetics , Stem Cells/cytology , Stem Cells/metabolism , Adolescent , Adult , Alkaline Phosphatase/metabolism , Cell Count , Cell Survival/genetics , Gene Expression Profiling , HEK293 Cells , Humans , Middle Aged , Molecular Probes/metabolism , Reproducibility of Results , Signal Transduction , Stem Cells/enzymology , Time Factors , Young AdultABSTRACT
Adipose-derived stem cells (ASCs) are a widely investigated type of mesenchymal stem cell with great potential for musculoskeletal regeneration. However, use of ASCs is complicated by their cellular heterogeneity, which exists at both the population and single-cell levels. This study demonstrates a live-cell assay to investigate gene expression in ASCs undergoing osteogenesis using fluorescently tagged DNA hybridization probes called molecular beacons. Three molecular beacons were designed to target mRNA sequences for alkaline phosphatase, type I collagen, and osteocalcin (ALPL, COL1A1, and BGLAP), genes characteristically expressed during osteogenesis. The percentage of cells expressing these genes in a population was monitored daily to quantify the uniformity of the differentiation process. Differentiating ASC populations were repeatedly measured in a nondestructive fashion over a 21-day period to obtain temporal gene expression data. Results showed consistent expression patterns for the investigated osteogenic genes in response to induction medium. Peak expression was observed at days 3-4 for ALPL, day 14 for COL1A1, and day 21 for BGLAP. Additionally, the differentiation response of sample populations became more uniform after 2 weeks in osteogenic induction medium, suggesting a syncing of ASCs occurs over time. These findings are consistent with previous studies of osteogenic differentiation and suggest that molecular beacons are a viable means to monitor the spatiotemporal gene expression of live, differentiating ASCs.
