Core-Shell poly-(D,l-Lactide-co-Glycolide)-chitosan Nanospheres with simvastatin-doxycycline for periodontal and osseous repair

Zein and hydroxypropyl methylcellulose acetate succinate microfibers combined with metronidazole benzoate and/or metronidazole-incorporated cellulose nanofibrils for potential periodontal treatment

The development of flexible and porous materials to control antibacterial delivery is a pivotal endeavor in medical science. In this study, we aimed to produce long and defect-free fibers made of zein and hydroxypropyl methylcellulose acetate succinate (HPMCAS) to be used as a platform for the release of metronidazole (MDZ) and metronidazole benzoate (BMDZ) to be potentially used in periodontal treatment. Microfibers prepared via electrospinning under a 2:3 (w/w) zein to HPMCAS ratio, containing 0.5 % (w/w) poly(ethylene oxide) (PEO) and 1 % (w/w) cellulose nanofibril (CNF) were loaded with 40 % (w/w) MDZ, 40 % (w/w) BMDZ, or a combination of 20 % (w/w) of each drug. The addition of CNF improved the electrospinning process, resulting in long fibers with reduced MDZ and BMDZ surface crystallization. MDZ- and BMDZ-incorporated fibers were semicrystalline and displayed commendable compatibility among drugs, nanocellulose and polymeric chains. Release tests showed that zein/HPMCAS/PEO fibers without CNF and with 20 % (w/w) MDZ/ 20 % (w/w) BMDZ released the drug at a slower and more sustained rate compared to other samples over extended periods (up to 5 days), which is a favorable aspect concerning periodontitis treatment.

Rational design of viscoelastic hydrogels for periodontal ligament remodeling and repair

The periodontal ligament (PDL) is a distinctive yet critical connective tissue vital for maintaining the integrity and functionality of tooth-supporting structures. However, PDL repair poses significant challenges due to the complexity of its mechanical microenvironment encompassing hard-soft-hard tissues, with the viscoelastic properties of the PDL being of particular interest. This review delves into the significant role of viscoelastic hydrogels in PDL regeneration, underscoring their utility in simulating biomimetic three-dimensional microenvironments. We review the intricate relationship between PDL and viscoelastic mechanical properties, emphasizing the role of tissue viscoelasticity in maintaining mechanical functionality. Moreover, we summarize the techniques for characterizing PDL's viscoelastic behavior. From a chemical bonding perspective, we explore various crosslinking methods and characteristics of viscoelastic hydrogels, along with engineering strategies to construct viscoelastic cell microenvironments. We present a detailed analysis of the influence of the viscoelastic microenvironment on cellular mechanobiological behavior and fate. Furthermore, we review the applications of diverse viscoelastic hydrogels in PDL repair and address current challenges in the field of viscoelastic tissue repair. Lastly, we propose future directions for the development of innovative hydrogels that will facilitate not only PDL but also systemic ligament tissue repair. STATEMENT OF SIGNIFICANCE.

Simvastatin-hydroxyapatite coatings prevent biofilm formation and improve bone formation in implant-associated infections

Implant-associated infections (IAIs) caused by biofilm formation are the most devastating complications of orthopedic surgery. Statins have been commonly and safely used drugs for hypercholesterolemia for many years. Here, we report that simvastatin-hydroxyapatite-coated titanium alloy prevents biofilm-associated infections. The antibacterial properties of simvastatin against Staphylococcus aureus and Staphylococcus epidermidis biofilms in vitro was confirmed by crystal violet staining and live-dead bacterial staining. We developed a simvastatin-and hydroxyapatite (Sim-HA)-coated titanium alloy via electrochemical deposition. Sim-HA coatings inhibited Staphylococcus aureus biofilm formation and improved the biocompatibility of the titanium alloy. Sim-HA coatings effectively prevented Staphylococcus aureus IAI in rat femurs, as confirmed by radiological assessment and histological examination. The antibacterial effects of the Sim-HA coatings were attributed to their inhibitory effects on biofilm formation, as verified by scanning electron microscopic observations and bacterial spread plate analysis. In addition, the Sim-HA coatings enhanced osteogenesis and osteointegration, as verified by micro-CT, histological evaluation, and biomechanical pull-out tests. In summary, Sim-HA coatings are promising implant materials for protection against biofilm-associated infections.

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Simvastatin-hydroxyapatite coatings were prepared on Ti6Al4V by electrochemical deposition process.

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The Simvastatin-hydroxyapatite coatings inhibited S. aureus biofilm formation and improved biocompatibility in vitro.

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The coatings exhibited antibacterial effects and improved bone formation in a rat femur IAI model.

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Simvastatin coatings are promising for application in orthopedic implants.

Drug delivery systems for oral disease applications

There are many restrictions on topical medications for the oral cavity. Various factors affect the topical application of drugs in the oral cavity, an open and complex environment. The complex physical and chemical environment of the oral cavity, such as saliva and food, will influence the effect of free drugs. Therefore, drug delivery systems have served as supporting structures or as carriers loading active ingredients, such as antimicrobial agents and growth factors (GFs), to promote antibacterial properties, tissue regeneration, and engineering for drug diffusion. These drug delivery systems are considered in the prevention and treatment of dental caries, periodontal disease, periapical disease, the delivery of anesthetic drugs, etc. These carrier materials are designed in different ways for clinical application, including nanoparticles, hydrogels, nanofibers, films, and scaffolds. This review aimed to summarize the advantages and disadvantages of different carrier materials. We discuss synthesis methods and their application scope to provide new perspectives for the development and preparation of more favorable and effective local oral drug delivery systems.

Sirolimus loaded chitosan functionalized poly (lactic-co-glycolic acid) (PLGA) nanoparticles for potential treatment of age-related macular degeneration

The usefulness of sirolimus (SIR) in the treatment of diseases that involve retinal degeneration like age-related macular degeneration (AMD) has been well documented. However, the problem still remains probably owing to the peculiar environment of the eye and/or unfavourable physiochemical profile of SIR. In the present work, we aimed to fabricate sirolimus loaded PLGA nanoparticles (SIR-PLGA-NP) and chitosan decorated PLGA nanoparticles (SIR-CH-PLGA-NP) to be administered via non-invasive subconjunctival route. Both the nanoparticles were characterized in terms of size, zeta potential, DSC, FTIR and XRD analysis. Quality by Design (QbD) approach was employed during the preparation of nanoparticles and the presence of chitosan coating was confirmed through thermogravimetric analysis and contact angle studies. Cationic polymer modification showed sustained in-vitro SIR release and enhanced ex-vivo scleral permeation and penetration. Further, SIR-CH-PLGA-NP revealed enhanced cellular uptake and thus, reduced lipopolysaccharide (LPS)-induced free-radicals generation by RAW 264.7 cells. The prepared nanoparticles were devoid of residual solvent and were found to be safe in HET-CAM analysis, RBCs damage analysis and histopathology studies. Moreover, high anti-angiogenic potential was observed in SIR-CH-PLGA-NP compared with SIR-PLGA-NP in chorioallantoic membrane (CAM) test. Overall, the current work opens up an avenue for further investigation of CH-PLGA-NP as SIR nanocarrier in the treatment of AMD.

Nanomedicine and Periodontal Regenerative Treatment

Current periodontal treatments aim to control bacterial infection and decrease inflammation. To optimize contemporary conventional treatments that present limitations owing to an inability to reach the lesion site, new methods are based on nanomedicine. Nanomedecine allows delivery of host-modulatory drugs or antibacterial molecules at the lesion site in an optimal concentration with decreased toxicity and risk of systemic side effects. Chitosan and polylactic-co-glycolic acid-loaded nanoparticles, carbon quantum dots, and mesoporous silicates open new perspectives in periodontitis management. The potential therapeutic impact of the main nanocarriers is discussed.

The recent advances in scaffolds for integrated periodontal regeneration

The periodontium is an integrated, functional unit of multiple tissues surrounding and supporting the tooth, including but not limited to cementum (CM), periodontal ligament (PDL) and alveolar bone (AB). Periodontal tissues can be destructed by chronic periodontal disease, which can lead to tooth loss. In support of the treatment for periodontally diseased tooth, various biomaterials have been applied starting as a contact inhibition membrane in the guided tissue regeneration (GTR) that is the current gold standard in dental clinic. Recently, various biomaterials have been prepared in a form of tissue engineering scaffold to facilitate the regeneration of damaged periodontal tissues. From a physical substrate to support healing of a single type of periodontal tissue to multi-phase/bioactive scaffold system to guide an integrated regeneration of periodontium, technologies for scaffold fabrication have emerged in last years. This review covers the recent advancements in development of scaffolds designed for periodontal tissue regeneration and their efficacy tested in vitro and in vivo. Pros and Cons of different biomaterials and design parameters implemented for periodontal tissue regeneration are also discussed, including future perspectives.

Natural Polymers for the Maintenance of Oral Health: Review of Recent Advances and Perspectives

The success of modern dental treatment is strongly dependent on the materials used both temporarily and permanently. Among all dental materials, polymers are a very important class with a wide spectrum of applications. This review aims to provide a state-of-the-art overview of the recent advances in the field of natural polymers used to maintain or restore oral health. It focuses on the properties of the most common proteins and polysaccharides of natural origin in terms of meeting the specific biological requirements in the increasingly demanding field of modern dentistry. The use of naturally derived polymers in different dental specialties for preventive and therapeutic purposes has been discussed. The major fields of application cover caries and the management of periodontal diseases, the fabrication of membranes and scaffolds for the regeneration of dental structures, the manufacturing of oral appliances and dentures as well as providing systems for oral drug delivery. This paper also includes a comparative characteristic of natural and synthetic dental polymers. Finally, the current review highlights new perspectives, possible future advancements, as well as challenges that may be encountered by researchers in the field of dental applications of polymers of natural origin.

Controlled Release of 18-β-Glycyrrhetinic Acid from Core-Shell Nanoparticles: Effects on Cytotoxicity and Intracellular Concentration in HepG2 Cell Line

18β-glycyrrhetinic acid (GA) is a pentacyclic triterpene with promising hepatoprotective and anti-Hepatocellular carcinoma effects. GA low water solubility however reduces its biodistribution and bioavailability, limiting its applications in biomedicine. In this work we used core-shell NPs made of PolyD-L-lactide-co-glycolide (PLGA) coated with chitosan (CS), prepared through an osmosis-based methodology, to efficiently entrap GA. NPs morphology was investigated with SEM and TEM and their GA payload was evaluated with a spectrophotometric method. GA-loaded NPs were administered to HepG2 cells and their efficiency in reducing cell viability was compared with that induced by the free drug in in vitro tests. Cell viability was evaluated by the MTT assay, as well as with Electric Cells-Substrate Impedance Sensing (ECIS), that provided a real-time continuous monitoring. It was possible to correlate the toxic effect of the different forms of GA with the bioavailability of the drug, evidencing the importance of real-time tests for studying the effects of bioactive substances on cell cultures.

Polysaccharide-Based Drug Delivery Systems for the Treatment of Periodontitis

Periodontal diseases are worldwide health problems that negatively affect the lifestyle of many people. The long-term effect of the classical treatments, including the mechanical removal of bacterial plaque, is not effective enough, causing the scientific world to find other alternatives. Polymer-drug systems, which have different forms of presentation, chosen depending on the nature of the disease, the mode of administration, the type of polymer used, etc., have become very promising. Hydrogels, for example (in the form of films, micro-/nanoparticles, implants, inserts, etc.), contain the drug included, encapsulated, or adsorbed on the surface. Biologically active compounds can also be associated directly with the polymer chains by covalent or ionic binding (polymer-drug conjugates). Not just any polymer can be used as a support for drug combination due to the constraints imposed by the fact that the system works inside the body. Biopolymers, especially polysaccharides and their derivatives and to a lesser extent proteins, are preferred for this purpose. This paper aims to review in detail the biopolymer-drug systems that have emerged in the last decade as alternatives to the classical treatment of periodontal disease.

The Benefits of Smart Nanoparticles in Dental Applications

Dentistry, as a branch of medicine, has undergone continuous evolution over time. The scientific world has focused its attention on the development of new methods and materials with improved properties that meet the needs of patients. For this purpose, the replacement of so-called "passive" dental materials that do not interact with the oral environment with "smart/intelligent" materials that have the capability to change their shape, color, or size in response to an externally stimulus, such as the temperature, pH, light, moisture, stress, electric or magnetic fields, and chemical compounds, has received much attention in recent years. A strong trend in dental applications is to apply nanotechnology and smart nanomaterials such as nanoclays, nanofibers, nanocomposites, nanobubbles, nanocapsules, solid-lipid nanoparticles, nanospheres, metallic nanoparticles, nanotubes, and nanocrystals. Among the nanomaterials, the smart nanoparticles present several advantages compared to other materials, creating the possibility to use them in various dental applications, including preventive dentistry, endodontics, restoration, and periodontal diseases. This review is focused on the recent developments and dental applications (drug delivery systems and restoration materials) of smart nanoparticles.