A functional chitosan membrane with grafted epigallocatechin-3-gallate and lovastatin enhances periodontal tissue regeneration in dogs

Pure Epigallocatechin-3-gallate-Assisted Green Synthesis of Highly Stable Titanium Dioxide Nanoparticles

Nanoparticles (NPs) are conventionally produced by using physical and chemical methods that are no longer in alignment with current society's demand for a low environmental impact. Accordingly, green synthesis approaches are considered a potential alternative due to the plant extracts that substitute some of the hazardous reagents. The general mechanism is based on the reducing power of natural products that allows the formation of NPs from a precursor solution. In this context, our study proposes a simple, innovative, and reproducible green approach for the synthesis of titanium dioxide (TiO2 NPs) that uses, for the first time, the major component of green tea (Camellia sinensis)-epigallocatechin-3-gallate (EGCG), a non-toxic, dietary, accessible, and bioactive molecule. The influence of EGCG on the formation of TiO2 NPs was analyzed by comparing the physicochemical characteristics of green synthesized NPs with the chemically obtained ones. The synthesis of bare TiO2 NPs was performed by hydrolysis of titanium isopropoxide in distilled water, and green TiO2 NPs were obtained in the same conditions, but in the presence of a 1 mM EGCG aqueous solution. The formation of TiO2 NPs was confirmed by UV-VIS and FTIR spectroscopy. SEM micrographs showed spherical particles with relatively low diameters. Our findings also revealed that green synthesized NPs were more stable in colloids than the chemically synthesized ones. However, the phytocompound negatively influenced the formation of a crystalline structure in the green synthesized TiO2 NPs. Furthermore, the synthesis of EGCG-TiO2 NPs could become a versatile choice for applications extending beyond photocatalysis, including promising prospects in the biomedical field.

Zeolites with Divalent Ions as Carriers in the Delivery of Epigallocatechin Gallate

Epigallocatechin gallate (EGCG) is a compound with very high therapeutic potential in the treatment of osteoporosis and cancer. The disadvantages of this compound are its low stability and low bioavailability. Therefore, carriers for EGCG are sought to increase its use. In this work, new carriers are proposed, i.e., zeolites containing divalent ions of magnesium, calcium, strontium, and zinc in their structure. EGCG is retained on the carrier surface by strong interactions with divalent ions. Due to the presence of strong interactions, EGCG is released in a controlled manner from the carrier-ion-EGCG drug delivery system. The results obtained in this work confirm the effectiveness of the preparation of new carriers. EGCG is released from the carriers depending on the pH; hence, it can be used both in osteoporosis and in the treatment of cancer. The divalent ion used affects the sorption and release of the drug. The obtained results indicate the great potential of the proposed carriers and their advantage over the carriers described in the literature.

Comparative study of the properties of lutein nanoliposomes coated with chitosan/(-)-epigallocatechin- 3-gallate (EGCG) complexes

BACKGROUND

Numerous positive effects have been attributed to lutein, a lipophilic nutrient, including resisting ultraviolet radiation and protecting retinal pigment epithelial (RPE) cells against blue light damage. It also has preventive effects against cardiovascular disease and cancer. However, its use could be limited by its poor stability and low bioaccessibility in the human digestive system. An encapsulation delivery system was therefore developed to resolve these limitations. In this study, chitosan-modified lutein nanoliposomes (CS-LNLs), chitosan-EGCG covalently modified lutein nanoliposomes (C-CS-EGCG-LNLs), and chitosan-EGCG noncovalently modified lutein nanoliposomes (non-C-CS-EGCG-LNLs) were designed. The average particle size, ζ-potential, and retention of lutein during storage were measured to indicate the physicochemical stability of the modified lutein nanoliposomes. The bioaccessibility of modified lutein nanoliposomes was also investigated to demonstrate the availability of lutein in the human digestive system.

RESULTS

First, Fourier-transform infrared spectroscopy (FTIR) verified that covalent bonds between chitosan and EGCG were formed. Subsequently, ζ-potential results revealed that C-CS-EGCG-LNLs had a relatively stable structure in comparison with lutein nanoliposomes (LNLs). The retention rate of lutein in CS-LNLs, C-CS-EGCG-LNLs, and non-C-CS-EGCG-LNLs was improved, especially in C-CS-EGCG-LNLs (at around 70% of lutein in initial system). An in vitro digestion experiment illustrated that CS-LNLs, C-CS-EGCG-LNLs, and non-C-CS-EGCG-LNLs presented relatively higher bioaccessibility, especially in C-CS-EGCG-LNLs (at around 33% of luein in initial system), which increased 2.5 and 1.65 times in comparison with free lutein and LNLs, respectively.

CONCLUSION

Overall, the results showed that C-CS-EGCG-LNLs presented greater physicochemical stability and bioaccessibility than LNLs, CS-LNLs, and non-C-CS-EGCG-LNLs. © 2023 Society of Chemical Industry.

Chitosan: A Potential Biopolymer in Drug Delivery and Biomedical Applications

Chitosan, a biocompatible and biodegradable polysaccharide derived from chitin, has surfaced as a material of promise for drug delivery and biomedical applications. Different chitin and chitosan extraction techniques can produce materials with unique properties, which can be further modified to enhance their bioactivities. Chitosan-based drug delivery systems have been developed for various routes of administration, including oral, ophthalmic, transdermal, nasal, and vaginal, allowing for targeted and sustained release of drugs. Additionally, chitosan has been used in numerous biomedical applications, such as bone regeneration, cartilage tissue regeneration, cardiac tissue regeneration, corneal regeneration, periodontal tissue regeneration, and wound healing. Moreover, chitosan has also been utilized in gene delivery, bioimaging, vaccination, and cosmeceutical applications. Modified chitosan derivatives have been developed to improve their biocompatibility and enhance their properties, resulting in innovative materials with promising potentials in various biomedical applications. This article summarizes the recent findings on chitosan and its application in drug delivery and biomedical science.

Drug-Loaded Chitosan Scaffolds for Periodontal Tissue Regeneration

Chitosan is a natural anionic polysaccharide with a changeable architecture and an abundance of functional groups; in addition, it can be converted into various shapes and sizes, making it appropriate for a variety of applications. This article examined and summarized current developments in chitosan-based materials, with a focus on the modification of chitosan, and presented an abundance of information about the fabrication and use of chitosan-derived products in periodontal regeneration. Numerous preparation and modification techniques for enhancing chitosan performance, as well as the uses of chitosan and its metabolites, were reviewed critically and discussed in depth in this study. Chitosan-based products may be formed into different shapes and sizes, considering fibers, nanostructures, gels, membranes, and hydrogels. Various drug-loaded chitosan devices were discussed regarding periodontal regeneration.

Periodontal Wound Healing and Regeneration: Insights for Engineering New Therapeutic Approaches

Periodontitis is a widespread inflammatory disease that leads to loss of the tooth supporting periodontal tissues. The few therapies available to regenerate periodontal tissues have high costs and inherent limitations, inspiring the development of new approaches. Studies have shown that periodontal tissues have an inherent capacity for regeneration, driven by multipotent cells residing in the periodontal ligament (PDL). The purpose of this review is to describe the current understanding of the mechanisms driving periodontal wound healing and regeneration that can inform the development of new treatment approaches. The biologic basis underlying established therapies such as guided tissue regeneration (GTR) and growth factor delivery are reviewed, along with examples of biomaterials that have been engineered to improve the effectiveness of these approaches. Emerging therapies such as those targeting Wnt signaling, periodontal cell delivery or recruitment, and tissue engineered scaffolds are described in the context of periodontal wound healing, using key in vivo studies to illustrate the impact these approaches can have on the formation of new cementum, alveolar bone, and PDL. Finally, design principles for engineering new therapies are suggested which build on current knowledge of periodontal wound healing and regeneration.

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.

An Iron Shield to Protect Epigallocatehin-3-Gallate from Degradation: Multifunctional Self-Assembled Iron Oxide Nanocarrier Enhances Protein Kinase CK2 Intracellular Targeting and Inhibition

Protein kinase CK2 is largely involved in cell proliferation and apoptosis and is generally recognized as an Achilles’ heel of cancer, being overexpressed in several malignancies. The beneficial effects of (−)-epigallocatechin-3-gallate (EGCG) in the prevention and treatment of several diseases, including cancer, have been widely reported. However, poor stability and limited bioavailability hinder the development of EGCG as an effective therapeutic agent. The combination of innovative nanomaterials and bioactive compounds into nanoparticle-based systems demonstrates the synergistic advantages of nanocomplexes as compared to the individual components. In the present study, we developed a self-assembled core-shell nanohybrid (SAMN@EGCG) combining EGCG and intrinsic dual-signal iron oxide nanoparticles (Surface Active Maghemite Nanoparticles). Interestingly, nano-immobilization on SAMNs protects EGCG from degradation, preventing its auto-oxidation. Most importantly, the nanohybrid was able to successfully deliver EGCG into cancer cells, displaying impressive protein kinase CK2 inhibition comparable to that obtained with the most specific CK2 inhibitor, CX-4945 (5.5 vs. 3 µM), thus promoting the phytochemical exploitation as a valuable alternative for cancer therapy. Finally, to assess the advantages offered by nano-immobilization, we tested SAMN@EGCG against Pseudomonas aeruginosa, a Gram-negative bacterium involved in severe lung infections. An improved antimicrobial effect with a drastic drop of MIC from 500 to 32.7 μM was shown.

Control Release of Adenosine Potentiate Osteogenic Differentiation within a Bone Integrative EGCG-g-NOCC/Collagen Composite Scaffold toward Guided Bone Regeneration in a Critical-Sized Calvarial Defect

The regeneration of critical-sized bone defects with biomimetic scaffolds remains clinically challenging due to avascular necrosis, chronic inflammation, and altered osteogenic activity. Two confounding mechanisms, efficacy manipulation, and temporal regulation dictate the scaffold's bone regenerative ability. Equally critical is the priming of the mesenchymal stromal cells (MSCs) toward lineage-specific differentiation into bone-forming osteoblast, which particularly depends on varied mechanochemical and biological cues during bone tissue regeneration. This study sought to design and develop an optimized osteogenic scaffold, adenosine/epigallocatechin gallate-N,O-carboxymethyl chitosan/collagen type I (AD/EGCG-g-NOCC@clgn I), having osteoinductive components toward swift bone regeneration in a calvarial defect BALB/c mice model. The ex vivo findings distinctly establish the pro-osteogenic potential of adenosine and EGCG, stimulating MSCs toward osteoblast differentiation with significantly increased expression of alkaline phosphatase, calcium deposits, and enhanced osteocalcin expression. Moreover, the 3D matrix recapitulates extracellular matrix (ECM) properties, provides a favorable microenvironment, structural support against mechanical stress, and acts as a reservoir for sustained release of osteoinductive molecules for cell differentiation, proliferation, and migration during matrix osteointegration observed. Evidence from in vivo experiments, micro-CT analyses, histology, and histomorphometry signify accelerated osteogenesis both qualitatively and quantitatively: effectual bone union with enhanced bone formation and new ossified tissue in 4 mm sized defects. Our results suggest that the optimized scaffold serves as an adjuvant to guide bone tissue regeneration in critical-sized calvarial defects with promising therapeutic efficacy.

Biopolymers Hybrid Particles Used in Dentistry

This literature review provides an overview of the fabrication and application of biopolymer hybrid particles in dentistry. A total of 95 articles have been included in this review. In the review paper, the common inorganic particles and biopolymers used in dentistry are discussed in general, and detailed examples of inorganic particles (i.e., hydroxyapatite, calcium phosphate, and bioactive glass) and biopolymers such as collagen, gelatin, and chitosan have been drawn from the scientific literature and practical work. Among the included studies, calcium phosphate including hydroxyapatite is the most widely applied for inorganic particles used in dentistry, but bioactive glass is more applicable and multifunctional than hydroxyapatite and is currently used in clinical practice. Today, biopolymer hybrid particles are receiving more attention as novel materials for several applications in dentistry, such as drug delivery systems, bone repair, and periodontal regeneration surgery. The literature published on the biopolymer gel-assisted synthesis of inorganic particles for dentistry is somewhat limited, and therefore, this article focuses on reviewing and discussing the biopolymer hybrid particles used in dentistry.

Targeting reactive oxygen species in stem cells for bone therapy

Reactive oxygen species (ROS) have emerged as key players in regulating the fate and function of stem cells from both non-hematopoietic and hematopoietic lineages in bone marrow, and thus affect the osteoblastogenesis-osteoclastogenesis balance and bone homeostasis. Accumulating evidence has linked ROS and associated oxidative stress with the progression of bone disorders, and ROS-based therapeutic strategies have appeared to achieve favorable outcomes in bone. We review current knowledge of the multifactorial roles and mechanisms of ROS as a target in bone pathology. In addition, we discuss emerging ROS-based therapeutic strategies that show potential for bone therapy. Finally, we highlight the opportunities and challenges facing ROS-targeted stem cell therapeutics for improving bone health.

Pacific white shrimp (Litopenaeus vannamei) shell chitosan and the conjugate with epigallocatechin gallate: Antioxidative and antimicrobial activities

Chitin was isolated from Pacific white shrimp (Litopenaeus vannamei) shell by demineralization and deproteinization using 1 M HCl (1:20, w/v) for 2 hr and 1 M NaOH (1:30 w/v) for 80 min at 70ºC, respectively, with 29.96% optimum yield. Thereafter, the chitin was deacetylated at various temperatures for different times, in which the chitosan prepared at 130ºC for 4 hr (CS-130-4) showed higher yield (73.11%), crystallinity index (19.75%), and 85.28% degree of deacetylation (DDA) as measured by ¹ H-NMR. CS-130-4 was then conjugated to epigallocatechin gallate (EGCG) at various concentrations (2-8%, w/w of chitosan). CS-130-4 was grafted with 8% EGCG (CE-8) had the higher conjugation efficiency (92.63%) and antimicrobial/antioxidant activities as compared to other conjugates (p < .05). ¹ H-NMR analysis also confirmed the successful conjugation of CE-8. All the conjugates were completely water soluble. Therefore, CE-8 may be used as the natural antimicrobial and antioxidant agents in various food products. PRACTICAL APPLICATIONS: Shrimp shells are generally considered as processing by-products of the shellfish industries and can cause environmental pollution when improperly disposed. Chitosan from shrimp shells has been widely produced but it is soluble mainly in acidic solutions, which limits its applications. However, grafting of epigallocatechin gallate (EGCG) onto chitosan yielded water-soluble conjugates with enhanced antioxidant and antimicrobial properties. Although several preservatives have been applied in foods, their health hazards have been a major concern. To mitigate this limitation, chitosan-EGCG conjugates could be employed as alternative natural preservatives or additives for shelf-life extension of various foods.

Development of a thermosensitive statin loaded chitosan-based hydrogel promoting bone healing

Statins have been proposed as potential adjuvant to periodontal treatment due to their pleiotropic properties. A new thermosensitive chitosan hydrogel loaded with statins (atorvastatin and lovastatin) nanoemulsions was synthesized to allow a spatially controlled local administration of active compounds at lesion site. Spontaneous nano-emulsification method was used to synthesize statins loaded nanoemulsions. In vitro, atorvastatin and lovastatin loaded nanoemulsions were cytocompatible and were able to be uptake by oral epithelial cells. Treatment of Porphyromonas gingivalis infected oral epithelial cells and gingival fibroblasts with atorvastatin and lovastatin loaded nanoemulsions decreased significantly pro-inflammatory markers expression (TNF-α and IL-1β) and pro-osteoclastic RANKL. Nevertheless, such treatment induced the expression of Bone sialoprotein 2 (BSP2) in osteoblast emphasizing the pro-healing properties of atorvastatin and lovastatin nanoemulsions. In vivo, in a calvarial bone defect model (2 mm), treatment with the hydrogel loaded with atorvastatin and lovastatin nanoemulsions induced a significant increase of the neobone formation in comparison with systemic administration of statins. This study demonstrates the potential of this statins loaded hydrogel to improve bone regeneration and to decrease soft tissue inflammation. Its use in the specific context of periodontitis management could be considered in the future with a reduced risk of side effects.

Recent advances in periodontal regeneration: A biomaterial perspective

Periodontal disease (PD) is one of the most common inflammatory oral diseases, affecting approximately 47% of adults aged 30 years or older in the United States. If not treated properly, PD leads to degradation of periodontal tissues, causing tooth movement, and eventually tooth loss. Conventional clinical therapy for PD aims at eliminating infectious sources, and reducing inflammation to arrest disease progression, which cannot achieve the regeneration of lost periodontal tissues. Over the past two decades, various regenerative periodontal therapies, such as guided tissue regeneration (GTR), enamel matrix derivative, bone grafts, growth factor delivery, and the combination of cells and growth factors with matrix-based scaffolds have been developed to target the restoration of lost tooth-supporting tissues, including periodontal ligament, alveolar bone, and cementum. This review discusses recent progresses of periodontal regeneration using tissue-engineering and regenerative medicine approaches. Specifically, we focus on the advances of biomaterials and controlled drug delivery for periodontal regeneration in recent years. Special attention is given to the development of advanced bio-inspired scaffolding biomaterials and temporospatial control of multi-drug delivery for the regeneration of cementum-periodontal ligament-alveolar bone complex. Challenges and future perspectives are presented to provide inspiration for the design and development of innovative biomaterials and delivery system for new regenerative periodontal therapy.

Combination of Zinc Hyaluronate and Metronidazole in a Lipid-Based Drug Delivery System for the Treatment of Periodontitis

BACKGROUND

Despite being a highly prevalent disease and a possible contributor to adult tooth loss, periodontitis possesses no well-established therapy. The aim of the recent study was the development and evaluation of a mucoadhesive monophase lipid formulation for the sustained local delivery of amoxicillin, metronidazole, and/or zinc hyaluronate or gluconate.

METHODS

To investigate our formulations, differential scanning calorimetry, X-ray diffraction, swelling, erosion, mucoadhesivity, drug release, and antimicrobial measurements were performed.

RESULTS

Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results show that the loaded drugs are in a suspended form, the softening of the formulations starts at body temperature, but a part remains solid, providing sustained release. Swelling of the lipid compositions is affected by the hydrophilic components, their concentration, and the strength of the coherent lipid structure, while their erosion is impacted by the emulsification of melted lipid components.

CONCLUSIONS

Results of drug release and antimicrobial effectiveness measurements show that a sustained release may be obtained. Amoxicillin had higher effectiveness against oral pathogens than metronidazole or zinc hyaluronate alone, but the combination of the two latter could provide similar effectiveness to amoxicillin. The applied mucoadhesive polymer may affect adhesivity, drug release through the swelling mechanism, and antimicrobial effect as well.

Contribution of Statins towards Periodontal Treatment: A Review

The pleiotropic effects of statins have been evaluated to assess their potential benefit in the treatment of various inflammatory and immune-mediated diseases including periodontitis. Herein, the adjunctive use of statins in periodontal therapy in vitro, in vivo, and in clinical trials was reviewed. Statins act through several pathways to modulate inflammation, immune response, bone metabolism, and bacterial clearance. They control periodontal inflammation through inhibition of proinflammatory cytokines and promotion of anti-inflammatory and/or proresolution molecule release, mainly, through the ERK, MAPK, PI3-Akt, and NF-κB pathways. Moreover, they are able to modulate the host response activated by bacterial challenge, to prevent inflammation-mediated bone resorption and to promote bone formation. Furthermore, they reduce bacterial growth, disrupt bacterial membrane stability, and increase bacterial clearance, thus averting the exacerbation of infection. Local statin delivery as adjunct to both nonsurgical and surgical periodontal therapies results in better periodontal treatment outcomes compared to systemic delivery. Moreover, combination of statin therapy with other regenerative agents improves periodontal healing response. Therefore, statins could be proposed as a potential adjuvant to periodontal therapy. However, optimization of the combination of their dose, type, and carrier could be instrumental in achieving the best treatment response.

Single Local Injection of Epigallocatechin Gallate-Modified Gelatin Attenuates Bone Resorption and Orthodontic Tooth Movement in Mice

Osteoclastic bone resorption enables orthodontic tooth movement (OTM) in orthodontic treatment. Previously, we demonstrated that local epigallocatechin gallate (EGCG) injection successfully slowed the rate of OTM; however, repeat injections were required. In the present study, we produced a liquid form of EGCG-modified gelatin (EGCG-GL) and examined the properties of EGCG-GL with respect to prolonging EGCG release, NF-E2-related factor 2 (Nrf2) activation, osteoclastogenesis inhibition, bone destruction, and OTM. We found EGCG-GL both prolonged the release of EGCG and induced the expression of antioxidant enzyme genes, such as heme oxygenase 1 (Hmox1) and glutamate-cysteine ligase (Gclc), in the mouse macrophage cell line, RAW264.7. EGCG-GL attenuated intracellular reactive oxygen species (ROS) levels were induced by the receptor activator of nuclear factor-kB ligand (RANKL) and inhibited RANKL-mediated osteoclastogenesis in vitro. An animal model of bone destruction, induced by repeat Lipopolysaccharide (LPS)-injections into the calvaria of male BALB/c mice, revealed that a single injection of EGCG-GL on day-1 could successfully inhibit LPS-mediated bone destruction. Additionally, experimental OTM of maxillary first molars in male mice was attenuated by a single EGCG-GL injection on day-1. In conclusion, EGCG-GL prolongs the release of EGCG and inhibits osteoclastogenesis via the attenuation of intracellular ROS signaling through the increased expression of antioxidant enzymes. These results indicate EGCG-GL would be a beneficial therapeutic approach both in destructive bone disease and in controlling alveolar bone metabolism.

Recent advances in flavonoid-grafted polysaccharides: Synthesis, structural characterization, bioactivities and potential applications

Plant derived flavonoids have been demonstrated to possess many valuable biological functions. In recent years, flavonoids have been successfully conjugated with polysaccharides through different graft copolymerization methods including chemical coupling, enzyme catalysis, free radical mediated grafting, and acid catalyzed condensation reactions. The successful grafting of flavonoids onto polysaccharides can be confirmed by several instrumental methods. The conjugation of flavonoids can significantly improve the antioxidant, antimicrobial, antitumor, hepatoprotective and enzyme inhibition properties of polysaccharides. Moreover, the applications of polysaccharides in food and pharmaceutical industries can be greatly broadened by grafting with flavonoids. Flavonoid-grafted polysaccharides can be developed as films for active packaging, hydrogels for controlled drug release, micelles for oral drug delivery, and emulsions for nutraceutical delivery. In general, the bioactivities and applications of conjugates are closely related to the type of flavonoid grafted, the grafting method used as well as the grafting efficiency. Recent advances in the synthesis, structural characterization, bioactivities and potential applications of flavonoid-grafted polysaccharides are summarized in this review.

Epigallocatechin Gallate-Modified Gelatin Sponges Treated by Vacuum Heating as a Novel Scaffold for Bone Tissue Engineering

Chemical modification of gelatin using epigallocatechin gallate (EGCG) promotes bone formation in vivo. However, further improvements are required to increase the mechanical strength and bone-forming ability of fabricated EGCG-modified gelatin sponges (EGCG-GS) for practical applications in regenerative therapy. In the present study, we investigated whether vacuum heating-induced dehydrothermal cross-linking of EGCG-GS enhances bone formation in critical-sized rat calvarial defects. The bone-forming ability of vacuum-heated EGCG-GS (vhEGCG-GS) and other sponges was evaluated by micro-computed tomography and histological staining. The degradation of sponges was assessed using protein assays, and cell morphology and proliferation were verified by scanning electron microscopy and immunostaining using osteoblastic UMR106 cells in vitro. Four weeks after the implantation of sponges, greater bone formation was detected for vhEGCG-GS than for EGCG-GS or vacuum-heated gelatin sponges (dehydrothermal cross-linked sponges without EGCG). In vitro experiments revealed that the relatively low degradability of vhEGCG-GS supports cell attachment, proliferation, and cell-cell communication on the matrix. These findings suggest that vacuum heating enhanced the bone forming ability of EGCG-GS, possibly via the dehydrothermal cross-linking of EGCG-GS, which provides a scaffold for cells, and by maintaining the pharmacological effect of EGCG.

Controlled release of lovastatin from poly(lactic-co-glycolic acid) nanoparticles for direct pulp capping in rat teeth

Statin at appropriate concentrations has been shown to induce odontoblastic differentiation, dentinogenesis, and angiogenesis. However, using a carrier to control statin release might reduce toxicity and enhance its therapeutic effects. The aim of this study was to prepare poly(d,l-lactide-co-glycolide acid) (PLGA) nanoparticles that contain lovastatin for application in direct pulp capping. The PLGA–lovastatin particle size was determined using dynamic light scattering measurements and transmission electron microscopy. In addition, the release of lovastatin was quantified using a UV–Vis spectrophotometer. The cytotoxicity and alkaline phosphatase (ALP) activity of PLGA–lovastatin nanoparticles on human dental pulp cells were investigated. Moreover, a real-time polymerase chain reaction (PCR) assay, Western blot analysis, and an enzyme-linked immunosorbent assay (ELISA) were used to examine the osteogenesis gene and protein expression of dentin sialophosphoprotein (DSPP), dentin matrix acidic phosphoprotein 1 (DMP1), and osteocalcin (OCN). Finally, PLGA–lovastatin nanoparticles and mineral trioxide aggregate (MTA) were compared as direct pulp capping materials in Wistar rat teeth. The results showed that the median diameter of PLGA–lovastatin nanoparticles was 174.8 nm and the cumulative lovastatin release was 92% at the 44th day. PLGA–lovastatin nanoparticles demonstrated considerably a lower cytotoxicity than free lovastatin at 5, 9, and 13 days of culture. For ALP activity, the ALP amount of PLGA–lovastatin (100 μg/mL) was significantly higher than that of the other groups for 9 and 13 days of culture. The real-time PCR assay, Western blot analysis, and ELISA assay showed that PLGA–lovastatin (100 μg/mL) induced the highest mRNA and protein expression of DSPP, DMP1, and OCN in pulp cells. Histological evaluation of the animal studies revealed that MTA was superior to the PLGA–lovastatin in stimulating the formation of tubular dentin in an observation period of 2 weeks. However, in an observation period of 4 weeks, it was evident that the PLGA–lovastatin and MTA were competitive in the formation of tubular reparative dentin and a complete dentinal bridge.