Minocycline-loaded PLGA electrospun membrane prevents alveolar bone loss in experimental peridontitis

Enhancing periodontal defences with nanofiber treatment: recent advances and future prospects

The term periodontal disease is used to define diseases characterised by inflammation and regeneration of the gums, cementum, supporting bone, and periodontal ligament. The conventional treatment involves the combination of scaling, root planning, and surgical approaches which are invasive and can pose certain challenges. Intrapocket administration of nanofibers can be used for overcoming challenges which can help in speeding up the wound repair process and can also be used to promote osteogenesis. To help make drug delivery more effective, nanofibers are an interesting solution. Nanofibers are nanosized 3D structures that can fill the pockets and have excellent mucoadhesion which prolongs their retention time on the target site. Moreover, their structure mimics the natural extracellular matrix which enables nanomaterials to sense local biological conditions and start cellular-level reprogramming to produce the necessary therapeutic efficacy. In this review, the significance of intrapocket administration of nanofibers using recent research for the management of periodontitis has been discussed in detail. Furthermore, we have discussed polymers used for the preparation of nanofibers, nanofiber production methods, and the patents associated with these developments. This comprehensive compilation of data serves as a valuable resource, consolidating recent developments in nanofiber applications for periodontitis management into one accessible platform.

Polyphenols-based intelligent oral barrier membranes for periodontal bone defect reconstruction

Periodontitis-induced periodontal bone defects significantly impact patients' daily lives. The guided tissue regeneration and guided bone regeneration techniques, which are based on barrier membranes, have brought hope for the regeneration of periodontal bone defects. However, traditional barrier membranes lack antimicrobial properties and cannot effectively regulate the complex oxidative stress microenvironment in periodontal bone defect areas, leading to unsatisfactory outcomes in promoting periodontal bone regeneration. To address these issues, our study selected the collagen barrier membrane as the substrate material and synthesized a novel barrier membrane (PO/4-BPBA/Mino@COL, PBMC) with an intelligent antimicrobial coating through a simple layer-by-layer assembly method, incorporating reactive oxygen species (ROS)-scavenging components, commercial dual-functional linkers and antimicrobial building blocks. Experimental results indicated that PBMC exhibited good degradability, hydrophilicity and ROS-responsiveness, allowing for the slow and controlled release of antimicrobial drugs. The outstanding antibacterial, antioxidant and biocompatibility properties of PBMC contributed to resistance to periodontal pathogen infection and regulation of the oxidative balance, while enhancing the migration and osteogenic differentiation of human periodontal ligament stem cells. Finally, using a rat periodontal bone defect model, the therapeutic effect of PBMC in promoting periodontal bone regeneration under infection conditions was confirmed. In summary, the novel barrier membranes designed in this study have significant potential for clinical application and provide a reference for the design of future periodontal regenerative functional materials.

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.

Small Extracellular Vesicles Laden Oxygen-Releasing Thermosensitive Hydrogel for Enhanced Antibacterial Therapy against Anaerobe-Induced Periodontitis Alveolar Bone Defect

Periodontitis is a bacterially induced chronic destructive inflammatory disease that leads to irreversible destruction of the tooth supporting structure, including connective tissue destruction, bone resorption, and even tooth loss. Until now, there has been no effective treatment to repair inflammatory bone loss in periodontitis. Recently, small extracellular vesicles (sEVs) emerged as the essential paracrine factors of mesenchymal stem cells (MSCs) that mediated tissue regeneration. However, limitations of antimicrobial activity associated with the use of sEVs have led to the urgency of new alternative strategies. Currently, we investigated the potential of a biocompatible oxygen-releasing thermosensitive hydrogel laded with sEVs secreted by bone marrow MSCs (BMMSCs) for the alveolar bone defect in periodontitis. The hydrogel composed of different polymers such as chitosan (CS), poloxamer 407 (P407), and cross-linked hyaluronic acid (c-HA) conglomerating is a kind of nanoporous structure material. Then, the gel matrix further encapsulated sEVs and calcium peroxide nanoparticles to realize the control of sEVs and oxygen release. Furthermore, ascorbic acid was added to achieve the REDOX equilibrium and acid-base equilibrium. The experiments in vivo and in vitro proved its good biocompatibility and effectively inhibited the growth of the periodontal main anaerobe, relieved periodontal pocket anaerobic infections, and promoted the periodontal defect regeneration. Therefore, this finding demonstrated that it was a promising approach for combating anaerobic pathogens with enhanced and selective properties in periodontal diseases, even in other bacteria-induced infections, for future clinical application.

In vitro evaluation of BMSCs early proliferation on minocycline-loaded electrospun nanofibers membrane

BACKGROUND

Electrospun nanofibers could simulate the natural extracellular matrix (ECM) of the host bone, while minocycline (MINO) is a broad-spectrum tetracycline antibiotic which has been found to have multiple non-antibiotics biological effects that promotes osteogenesis in vitro and in vivo.

OBJECTIVE

The present study aims at constructing a polylactic acid (PLA) electrospun nanofiber membrane loaded with MINO to enhance Bone marrow mesenchymal stem cells (BMSCs) adhesion and proliferation for early clinical treatment.

METHODS

The MINO-PLA membrane were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and in vitro drug release study. The antibacterial ability was also investigated. In addition, in vitro cellular proliferation experiment was performed to verify whether the PLA electrospun nanofibers membrane loaded with MINO enhance BMSCs adhesion and proliferation.

RESULTS

Analyzing the drug release and cell growth results, it was found that only the effective concentration of MINO-PLA could help the growth of BMSCs in the short term. This is related to the drug release rate of MINO-PLA and the initial concentration of MINO.

CONCLUSION

This study shows that by controlling the concentration and release rate of MINO with electrospinning PLA, BMSCs could proliferate on it, and a new bone repair material had been made in this study.

Resorbable GBR Scaffolds in Oral and Maxillofacial Tissue Engineering: Design, Fabrication, and Applications

Guided bone regeneration (GBR) is a promising technique in bone tissue engineering that aims to replace lost or injured bone using resorbable scaffolds. The promotion of osteoblast adhesion, migration, and proliferation is greatly aided by GBR materials, and surface changes are critical in imitating the natural bone structure to improve cellular responses. Moreover, the interactions between bioresponsive scaffolds, growth factors (GFs), immune cells, and stromal progenitor cells are essential in promoting bone regeneration. This literature review comprehensively discusses various aspects of resorbable scaffolds in bone tissue engineering, encompassing scaffold design, materials, fabrication techniques, and advanced manufacturing methods, including three-dimensional printing. In addition, this review explores surface modifications to replicate native bone structures and their impact on cellular responses. Moreover, the mechanisms of bone regeneration are described, providing information on how immune cells, GFs, and bioresponsive scaffolds orchestrate tissue healing. Practical applications in clinical settings are presented to underscore the importance of these principles in promoting tissue integration, healing, and regeneration. Furthermore, this literature review delves into emerging areas of metamaterials and artificial intelligence applications in tissue engineering and regenerative medicine. These interdisciplinary approaches hold immense promise for furthering bone tissue engineering and improving therapeutic outcomes, leading to enhanced patient well-being. The potential of combining material science, advanced manufacturing, and cellular biology is showcased as a pathway to advance bone tissue engineering, addressing a variety of clinical needs and challenges. By providing this comprehensive narrative, a detailed, up-to-date account of resorbable scaffolds' role in bone tissue engineering and their transformative potential is offered.

Calcium phosphate cement with minocycline hydrochloride-loaded gelatine microspheres for peri-implantitis treatment

OBJECTIVES

This study aimed to fabricate an antibacterial calcium phosphate cement (CPC) with minocycline hydrochloride (MINO)-loaded gelatine microspheres (GMs) as a local drug delivery system for the treatment of peri‑implantitis.

METHODS

CPC/GMs(MINO), incorporating MINO-loaded GMs into CPC, was developed and characterised using scanning electron microscopy (SEM), X-ray diffraction (XRD), and drug release profiling. The antibacterial activity against Porphyromonas gingivalis and Fusobacterium nucleatum was evaluated. Bone mesenchymal stem cells (BMSCs) were cultured in the extracts of the developed cements to evaluate osteoinductivity in vitro. Furthermore, a rabbit femoral model was established to evaluate osteogenic ability in vivo.

RESULTS

SEM and XRD confirmed the porous structure and chemical stability of CPC/GMs(MINO). The release profile showed a sustained release of MINO from CPC/GMs(MINO), reaching an equilibrium state on the 14th day with a cumulative release ratio of approximately 84%. For antibacterial assays, the inhibition zone of CPC/GMs(MINO) was 3.67 ± 0.31 cm for P. gingivalis and 7.47 ± 0.50 cm for F. nucleatum. Most bacteria seeded on CPC/GMs(MINO) died after 24 h of culture. In addition, CPC/GMs(MINO) significantly enhanced alkaline phosphatase activity, osteogenic gene expression, and BMSC mineralisation compared with CPC/GMs and the control group (P < 0.05). The in vivo results showed that CPC/GMs(MINO) possessed a higher quality and quantity of bone formation and maturation than CPC/GMs and CPC.

CONCLUSIONS

CPC/GMs(MINO) showed excellent antibacterial activity against pathogens associated with peri‑implantitis and demonstrated good osteoinductivity and osteogenic ability.

CLINICAL SIGNIFICANCE

Peri-implantitis is among the most common and challenging biological complications associated with dental implants. In this study, MINO-loaded GMs were incorporated into CPC, which endowed the composite cement with excellent antibacterial and osteogenic abilities, demonstrating its potential as a bone graft substitute for treating peri‑implantitis.

Biopolymers and Their Application in Bioprinting Processes for Dental Tissue Engineering

Dental tissues are composed of multiple tissues with complex organization, such as dentin, gingiva, periodontal ligament, and alveolar bone. These tissues have different mechanical and biological properties that are essential for their functions. Therefore, dental diseases and injuries pose significant challenges for restorative dentistry, as they require innovative strategies to regenerate damaged or missing dental tissues. Biomimetic bioconstructs that can effectively integrate with native tissues and restore their functionalities are desirable for dental tissue regeneration. However, fabricating such bioconstructs is challenging due to the diversity and complexity of dental tissues. This review provides a comprehensive overview of the recent developments in polymer-based tissue engineering and three-dimensional (3D) printing technologies for dental tissue regeneration. It also discusses the current state-of-the-art, focusing on key techniques, such as polymeric biomaterials and 3D printing with or without cells, used in tissue engineering for dental tissues. Moreover, the final section of this paper identifies the challenges and future directions of this promising research field.

Role of various pharmacologic agents in alveolar bone regeneration: A review

Alveolar bone and gingiva are components of the periodontium that house the tooth. It constantly adapts itself to the masticatory forces and position of the tooth. However, localized diseases like chronic periodontitis and certain systemic diseases destroy periodontal tissues, which include the alveolar bone. Various pharmacological agents are being explored for their pleiotropic properties to combat the destruction of alveolar bone. This review focuses on the role of pharmacological agents in alveolar bone regeneration.

Doxycycline-doped collagen membranes accelerate in vitro osteoblast proliferation and differentiation

OBJECTIVE

The aim of the study was to evaluate the effect of doxycycline- and dexamethasone-doped collagen membranes on the proliferation and differentiation of osteoblasts.

BACKGROUND

Collagen barrier membranes are frequently used to promote bone regeneration and to boost this biological activity their functionalization with antibacterial and immunomodulatory substances has been suggested.

METHODS

The design included commercially available collagen membranes doped with doxycycline (Dox-Col-M) or dexamethasone (Dex-Col-M), as well as undoped membranes (Col-M) as controls, which were placed in contact with cultured MG63 osteoblast-like cells (ATCC). Cell proliferation was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay and differentiation by measuring the alkaline phosphatase (ALP) activity using spectrophotometry. Real-time quantitative polymerase chain reaction was used to study the expression of the genes: Runx-2, OSX, ALP, OSC, OPG, RANKL, Col-I, BMP-2, BMP-7, TGF-β1, VEGF, TGF-βR1, TGF-βR2, and TGF-βR3. Scanning electron microscopy was used to study osteoblast morphology. Data were assessed using one-way analysis of variance or Kruskal-Wallis tests, once their distribution normality was assessed by Kolmogorov-Smirnov tests (p > .05). Bonferroni for multiple comparisons were carried out (p < .05).

RESULTS

Osteoblast proliferation was significantly enhanced in the functionalized membranes as follows: (Col-M < Dex-Col-M < Dox-Col-M). ALP activity was significantly higher on cultured osteoblasts on Dox-Col-M. Runx-2, OSX, ALP, OSC, BMP-2, BMP-7, TGF-β1, VEGF, TGF-βR1, TGF-βR2, and TGF-βR3 were overexpressed, and RANKL was down-regulated in osteoblasts cultured on Dox-Col-M. The osteoblasts cultured in contact with the functionalized membranes demonstrated an elongated spindle-shaped morphology.

CONCLUSION

The functionalization of collagen membranes with Dox promoted an increase in the proliferation and differentiation of osteoblasts.

Enhanced anti-biofilm activity of the minocycline-and-gallium-nitrate using niosome wrapping against Acinetobacter baumannii in C57/BL6 mouse pneumonia model

Acinetobacter baumannii is a worldwide health issue in terms of its high antibiotic resistance and ability to form biofilms. Nanoparticles (NPs) with high biocompatibility, high penetrating ability, and low medication dose can successfully treat the antibiotic-resistant infections. In this research, the anti-biofilm activity of niosomes containing minocycline and gallium nitrate (GaN) against A. baumannii biofilm was determined. In order to improve their anti-biofilm properties, minocycline and GaN were encapsulated in niosomes as biocompatible drug carriers. The niosomes' size, zeta potential, shape, stability, drug entrapment efficacy, drug release pattern and antibacterial activity were assessed. Several clinical samples were isolated from the lungs of patients hospitalized at Loghman hospital, Tehran, Iran. The biofilm formation of most lethal clinical isolates of A. baumannii was analyzed. The pneumonia model was generated by intranasally administering A. baumannii suspension to anesthetized mice whose immune systems was compromised twice by cyclophosphamide. Lung infection of the mouse with A. baumannii was confirmed using PCR. After treatment, the lungs were excised under sterile conditions and stained with hematoxylin and eosin (H&E) to determine histological symptoms, inflammation and intercellular secretions. The niosomes contained minocycline and GaN had an average size of 230 nm and a zeta potential of -40 mV, respectively. The percentage of drug entrapment and delayed drug release was both high in niosomal formulations. Niosomes containing minocycline and GaN dispersed 1, 3 and 5 day old biofilms. The mice given the combination of two compounds required less time to be treated than the animals given the single medication (minocycline). The minocycline& GaN-loaded niosomes could be considered as promising candidates to treat the infections caused by A. baumannii biofilm.

Coaxial electrospun nanofibers as drug delivery system for local treatment of periodontitis

OBJECTIVES

The aim of the present study was to prepare resorbable polylactide fibers for periodontitis treatment using coaxial electrospinning to optimize the release of metronidazole (MNA) by reducing the initial burst effect.

METHODS

Poly(L-lactide-co-D,L-lactide) (PLA) fibers mats with different distributions of metronidazole (MNA) were manufactured by coaxial electrospinning (COAX). By COAX spinning the central core of the fiber was enriched with 40% MNA (m/m), while the sheath of the fiber consisted of PLA only (test group). In contrast, fibers of the control group were prepared by conventional electrospinning with the same amount of MNA but with a homogenous drug distribution (HDD - homogenously distributed drug). The release of MNA was determined by analyzing aliquots from the fiber mats using UV-VIS spectroscopy. Agar diffusion tests were carried out to determine the antibacterial effect on periodontopathogenic bacteria. Biocompatibility was tested in direct contact to human gingival fibroblasts (HGF) for two days.

RESULTS

The COAX mats showed a retarded drug release compared to the conventional HDD fibers. After 24 h, 64% of total MNA was released cumulatively from the COAX fibers while 90% of the MNA was released from the HDD fibers (controls). The antibacterial effect of COAX fibers was significantly higher after 24 h compared to the HDD fibers. Cell cultivation revealed significant higher numbers of vital cells among the COAX mats.

SIGNIFICANCE

COAX fibers showed improved sustained MNA release compared to conventional fibers and can be seen as potential drug delivery systems in local periodontitis treatment.

Electrospun Nanofibers for Periodontal Treatment: A Recent Progress

Periodontitis is a major threat to oral health, prompting scientists to continuously study new treatment techniques. The nanofibrous membrane prepared via electrospinning has a large specific surface area and high porosity. On the one hand, electrospun nanofibers can improve the absorption capacity of proteins and promote the expression of specific genes. On the other hand, they can improve cell adhesion properties and prevent fibroblasts from passing through the barrier membrane. Therefore, electrospinning has unique advantages in periodontal treatment. At present, many oral nanofibrous membranes with antibacterial, anti-inflammatory, and tissue regeneration properties have been prepared for periodontal treatment. First, this paper introduces the electrospinning process. Then, the commonly used polymers of electrospun nanofibrous membranes for treating periodontitis are summarized. Finally, different types of nanofibrous membranes prepared via electrospinning for periodontal treatment are presented, and the future evolution of electrospinning to treat periodontitis is described.

Gradual Drug Release Membranes and Films Used for the Treatment of Periodontal Disease

Periodontitis is an inflammatory disease that, if not treated, can cause a lot of harm to the oral cavity, to the patients' quality of life, and to the entire community. There is no predictable standardized treatment for periodontitis, but there have been many attempts, using antibiotics, tissue regeneration techniques, dental scaling, or root planning. Due to the limits of the above-mentioned treatment, the future seems to be local drug delivery systems, which could gradually release antibiotics and tissue regeneration inducers at the same time. Local gradual release of antibiotics proved to be more efficient than systemic administration. In this review, we have made a literature search to identify the articles related to this topic and to find out which carriers have been tested for drug release as an adjuvant in the treatment of periodontitis. Considering the inclusion and exclusion criteria, 12 articles were chosen to be part of this review. The selected articles indicated that the drug-releasing carriers in periodontitis treatment were membranes and films fabricated from different types of materials and through various methods. Some of the drugs released by the films and membranes in the selected articles include doxycycline, tetracycline, metronidazole, levofloxacin, and minocycline, all used with good outcome regarding their bactericide effect; BMP-2, Zinc-hydroxyapatite nanoparticles with regenerative effect. The conclusion derived from the selected studies was that gradual drug release in the periodontal pockets is a promising strategy as an adjuvant for the treatment of periodontal disease.

Antibiotic-Loaded Polymeric Barrier Membranes for Guided Bone/Tissue Regeneration: A Mini-Review

Polymeric membranes are frequently used for bone regeneration in oral and periodontal surgery. Polymers provide adequate mechanical properties (i.e., Young’s modulus) to support oral function and also pose some porosity with interconnectivity to permit for cell proliferation and migration. Bacterial contamination of the membrane is an event that may lead to infection at the bone site, hindering the clinical outcomes of the regeneration procedure. Therefore, polymeric membranes have been proposed as carriers for local antibiotic therapy. A literature search was performed for papers, including peer-reviewed publications. Among the different membranes, collagen is the most employed biomaterial. Collagen membranes and expanded polytetrafluoroethylene loaded with tetracyclines, and polycaprolactone with metronidazole are the combinations that have been assayed the most. Antibiotic liberation is produced in two phases. A first burst release is sometimes followed by a sustained liberation lasting from 7 to 28 days. All tested combinations of membranes and antibiotics provoke an antibacterial effect, but most of the time, they were measured against single bacteria cultures and usually non-specific pathogenic bacteria were employed, limiting the clinical relevance of the attained results. The majority of the studies on animal models state a beneficial effect of these antibiotic functionalized membranes, but human clinical assays are scarce and controversial.

Engineering Electrospun Nanofibers for the Treatment of Oral Diseases

With the increase of consumption of high-sugar foods, beverages, tobacco, and alcohol, the incidence rate of oral diseases has been increasing year by year. Statistics showed that the prevalence of oral diseases such as dental caries, dental pulpal disease, and periodontal disease has reached as high as 97% in 2015 in China. It is thus urgent to develop functional materials or products for the treatment of oral diseases. Electrospinning has been a widely used technology that is capable of utilizing polymer solution to generate micro/nano fibers under an appropriate high voltage condition. Owing to their excellent structures and biological performances, materials prepared by electrospinning technology have been used for a wide range of oral-related applications, such as tissue restoration, controlled drug release, anti-cancer, etc. In this regard, this article reviews the application and progress of electrospun nanofibers to various oral diseases in recent years. Firstly, engineering strategies of a variety of nanofiber structures together with their resultant functions will be introduced. Then, biological functions of electrospun nanofibers as well as their applications in the treatment of oral diseases are summarized and demonstrated. Finally, the development viewpoint of functional nanofibers is prospected, which is expected to lay the foundation and propose the direction for further clinical application.

Amniotic Epithelial Stem Cells Counteract Acidic Degradation By-Products of Electrospun PLGA Scaffold by Improving Their Immunomodulatory Profile In Vitro

Electrospun poly(lactic-co-glycolic acid) (PLGA) scaffolds with highly aligned fibers (ha-PLGA) represent promising materials in the field of tendon tissue engineering (TE) due to their characteristics in mimicking fibrous extracellular matrix (ECM) of tendon native tissue. Among these properties, scaffold biodegradability must be controlled allowing its replacement by a neo-formed native tendon tissue in a controlled manner. In this study, ha-PLGA were subjected to hydrolytic degradation up to 20 weeks, under di-H₂O and PBS conditions according to ISO 10993-13:2010. These were then characterized for their physical, morphological, and mechanical features. In vitro cytotoxicity tests were conducted on ovine amniotic epithelial stem cells (oAECs), up to 7 days, to assess the effect of non-buffered and buffered PLGA by-products at different concentrations on cell viability and their stimuli on oAECs’ immunomodulatory properties. The ha-PLGA scaffolds degraded slowly as evidenced by a slight decrease in mass loss (14%) and average molecular weight (35%), with estimated degradation half-time of about 40 weeks under di-H₂O. The ultrastructure morphology of the scaffolds showed no significant fiber degradation even after 20 weeks, but alteration of fiber alignment was already evident at week 1. Moreover, mechanical properties decreased throughout the degradation times under wet as well as dry PBS conditions. The influence of acid degradation media on oAECs was dose-dependent, with a considerable effect at 7 days’ culture point. This effect was notably reduced by using buffered media. To a certain level, cells were able to compensate the generated inflammation-like microenvironment by upregulating IL-10 gene expression and favoring an anti-inflammatory rather than pro-inflammatory response. These in vitro results are essential to better understand the degradation behavior of ha-PLGA in vivo and the effect of their degradation by-products on affecting cell performance. Indeed, buffering the degradation milieu could represent a promising strategy to balance scaffold degradation. These findings give good hope with reference to the in vivo condition characterized by physiological buffering systems.

Metronidazole- and Amoxicillin-Loaded PLGA and PCL Nanofibers as Potential Drug Delivery Systems for the Treatment of Periodontitis: In Vitro and In Vivo Evaluations

The purpose of this study was to prepare poly (D-L) lactide-co-glycolide (PLGA) and poly ε-caprolactone (PCL) nanofibers containing metronidazole and amoxicillin using an electrospinning process as intrapocket sustained-release drug delivery systems for the treatment of periodontal diseases. Scanning electron microscopy showed that the drug containing PLGA and PCL nanofibers produced from the electrospinning process was uniform and bead-free in morphology. The obtained nanofibers had a strong structure and resisted external tension according to the tensiometry results. The cytotoxicity results indicated acceptable cell viability (>80%). Quantification by high-performance liquid chromatography showed almost complete in vitro drug release between 7 and 9 days, whereas 14 days were required for complete drug release in vivo. No significant signs of irritation or inflammatory reaction were detected after three weeks of subcutaneous implantation of nanofibers in the animal models, thus indicating suitable compatibility. The results therefore suggest that the designed nanofibers can be used as potential commercial formulations in the treatment of periodontitis as controlled-release intrapocket drug delivery systems that can increase patient compliance. This is due to their ability to reduce the frequency of administration from three times daily in a systemic manner to once weekly as local delivery.

Recent applications of electrical, centrifugal, and pressurised emerging technologies for fibrous structure engineering in drug delivery, regenerative medicine and theranostics

Advancements in technology and material development in recent years has led to significant breakthroughs in the remit of fiber engineering. Conventional methods such as wet spinning, melt spinning, phase separation and template synthesis have been reported to develop fibrous structures for an array of applications. However, these methods have limitations with respect to processing conditions (e.g. high processing temperatures, shear stresses) and production (e.g. non-continuous fibers). The materials that can be processed using these methods are also limited, deterring their use in practical applications. Producing fibrous structures on a nanometer scale, in sync with the advancements in nanotechnology is another challenge met by these conventional methods. In this review we aim to present a brief overview of conventional methods of fiber fabrication and focus on the emerging fiber engineering techniques namely electrospinning, centrifugal spinning and pressurised gyration. This review will discuss the fundamental principles and factors governing each fabrication method and converge on the applications of the resulting spun fibers; specifically, in the drug delivery remit and in regenerative medicine.

A Review of Systemic Minocycline Side Effects and Topical Minocycline as a Safer Alternative for Treating Acne and Rosacea

Resistance of Cutibacterium acnes to topical antibiotics historically used to treat acne (topical erythromycin and clindamycin and, more recently, topical azithromycin and clarithromycin) has been steadily increasing and new topical antibiotics are needed. Minocycline is a semisynthetic tetracycline-derived antibiotic currently used systemically to treat a wide range of infections caused by Gram-negative and Gram-positive bacteria. In addition to its antibiotic activity, minocycline possesses anti-inflammatory properties, such as the downregulation of proinflammatory cytokine production, suppression of neutrophil chemotaxis, activation of superoxide dismutase, and inhibition of phagocytosis, among others. These characteristics make minocycline a valuable agent for treatment of dermatological diseases such as acne vulgaris and papulopustular rosacea. However, more frequent or serious adverse effects have been observed upon the systemic administration of minocycline than with other tetracyclines. Examples of serious adverse effects include hypersensitivity syndrome reaction, drug-induced lupus, idiopathic intracranial hypertension, and other autoimmune syndromes that may cause death. Here, we review adverse effects and drug–drug interactions observed with oral administration of minocycline and contrast this with topical minocycline formulations recently approved or under development for effectively treating dermatological disorders with fewer adverse effects and less drug interaction.

Recent advances in PLGA-based biomaterials for bone tissue regeneration

Bone regeneration is an interdisciplinary complex lesson, including but not limited to materials science, biomechanics, immunology, and biology. Having witnessed impressive progress in the past decades in the development of bone substitutes; however, it must be said that the most suitable biomaterial for bone regeneration remains an area of intense debate. Since its discovery, poly (lactic-co-glycolic acid) (PLGA) has been widely used in bone tissue engineering due to its good biocompatibility and adjustable biodegradability. This review systematically covers the past and the most recent advances in developing PLGA-based bone regeneration materials. Taking the different application forms of PLGA-based materials as the starting point, we describe each form's specific application and its corresponding advantages and disadvantages with many examples. We focus on the progress of electrospun nanofibrous scaffolds, three-dimensional (3D) printed scaffolds, microspheres/nanoparticles, hydrogels, multiphasic scaffolds, and stents prepared by other traditional and emerging methods. Finally, we briefly discuss the current limitations and future directions of PLGA-based bone repair materials. STATEMENT OF SIGNIFICANCE: As a key synthetic biopolymer in bone tissue engineering application, the progress of PLGA-based bone substitute is impressive. In this review, we summarized the past and the most recent advances in the development of PLGA-based bone regeneration materials. According to the typical application forms and corresponding crafts of PLGA-based substitutes, we described the development of electrospinning nanofibrous scaffolds, 3D printed scaffolds, microspheres/nanoparticles, hydrogels, multiphasic scaffolds and scaffolds fabricated by other manufacturing process. Finally, we briefly discussed the current limitations and proposed the newly strategy for the design and fabrication of PLGA-based bone materials or devices.

Effects of Limosilactobacillus fermentum CCFM1139 on experimental periodontitis in rats

Periodontitis is a polymicrobial inflammatory disease often characterized by the excessive colonization of Porphyromonas gingivalis and Fusobacterium nucleatum, which causes alveolar bone resorption and advanced oral inflammation. This study aimed to evaluate the effect of Limosilactobacillus fermentum CCFM1139 on experimental periodontitis induced following ligature and infection with P. gingivalis and F. nucleatum in vivo. The results showed that L. fermentum CCFM1139 significantly reduced weight loss associated with periodontal inflammation (p < 0.05), while decreasing both the P. gingivalis and F. nucleatum populations within the oral cavity of rats (p < 0.05) and regulating the expression of tumor necrosis factor-alpha, interleukin (IL)-1 beta, and IL-8 in the periodontal tissue (p < 0.05). Microcomputed tomography (micro-CT) and histopathological examination revealed that L. fermentum CCFM1139 supplementation reduced the level of alveolar bone loss and bone porosity and increased bone volume (p < 0.05) in the experimental animals. Furthermore, L. fermentum CCFM1139 exhibited promising effects in preventing the deepening of the periodontal pocket and the increase in the gap between adjacent molars. Thus L. fermentum CCFM1139 was shown to have solid potential as an oral probiotic for protection against periodontitis suggesting that this may be a good candidate in the production of a new functional food for improving periodontitis.

Doxycycline-Doped Polymeric Membranes Induced Growth, Differentiation and Expression of Antigenic Phenotype Markers of Osteoblasts

Polymeric membranes are employed in guided bone regeneration (GBR) as physical barriers to facilitate bone in-growth. A bioactive and biomimetic membrane with the ability to participate in the healing and regeneration of the bone is necessary. The aim of the present study was to analyze how novel silicon dioxide composite membranes functionalized with zinc or doxycycline can modulate the osteoblasts' proliferation, differentiation, and expression of selected antigenic markers related to immunomodulation. Nanostructured acrylate-based membranes were developed, blended with silica, and functionalized with zinc or doxycycline. They were subjected to MG63 osteoblast-like cells culturing. Proliferation was assessed by MTT-assay, differentiation by evaluating the alkaline phosphatase activity by a spectrophotometric method and antigenic phenotype was assessed by flow cytometry for selected markers. Mean comparisons were conducted by one-way ANOVA and Tukey tests (p < 0.05). The blending of silica nanoparticles in the tested non-resorbable polymeric scaffold improved the proliferation and differentiation of osteoblasts, but doxycycline doped scaffolds attained the best results. Osteoblasts cultured on doxycycline functionalized membranes presented higher expression of CD54, CD80, CD86, and HLA-DR, indicating a beneficial immunomodulation activity. Doxycycline doped membranes may be a potential candidate for use in GBR procedures in several challenging pathologies, including periodontal disease.

Electrosprayed minocycline hydrochloride-loaded microsphere/SAIB hybrid depot for periodontitis treatment

Minocycline hydrochloride (MINO) has been one of the most frequently used antibiotics in the treatment of periodontitis due to its antibacterial activity and osteogenesis effects; however, high levels of MINO administered during the treatment halt the formation of new bone. Therefore, the purpose of the present study was to prepare a MINO-microsphere/sucrose acetate isobutyrate (SAIB) hybrid depot to reduce the burst release of MINO and ensure antibacterial and osteogenesis effects of MINO in the treatment of periodontitis. Uniform microspheres, approximately 5 µm size, with a slightly rough surface and different MINO loading (10, 12, and 14%) were prepared, and the microspheres were added into SAIB, after which the burst release significantly decreased from 66.18 to 2.92%, from 71.82 to 3.82%, and from 73.35 to 4.45%, respectively, and the release from all the MINO-microspheres/SAIB hybrid depots lasted for 77 days. In addition, cytotoxicity test showed that the MINO-microsphere with 12% drug loading promoted the proliferation of osteoblasts the most and was subsequently used in vivo experiments. Moreover, in the model of ligatured-induced periodontitis in SD rats, the MINO-microsphere/SAIB hybrid depot not only significantly increased the alveolar bone height and bone volume but also reduced the inflammation of the periodontal tissue. Additionally, it also inhibited the expression of the receptor activator of nuclear factor-kappa B ligand (RANKL) and promoted the expression of osteoprotegerin (OPG).. These results indicated that the MINO-microsphere/SAIB hybrid depot might be promising in the treatment of periodontitis.

Antibacterial Collagen Composite Membranes Containing Minocycline

Collagen membranes have been used as bioresorbable barrier membranes in guided tissue/bone regeneration. However, the collagen membranes currently used in clinics lack an active antibacterial function, although infection at surgical sites presents a realistic challenge for guided tissue/bone regeneration. In this study, we successfully prepared novel and advanced collagen composite membranes from collagen and complexes of heparin and chelates of minocycline and Ca²⁺ ions. These membranes were characterized for chemical structures, morphology, elemental compositions and tensile strength. In vitro release studies were conducted to evaluate the release kinetics of minocycline from these membranes. Agar disk diffusion assays were used to assess their sustained antibacterial capability against model pathogenic bacteria Staphylococcus aureus. The chemical and physical characterization confirmed the successful synthesis of minocycline-loaded collagen composite membranes, namely NCCM-1 and NCCM-2. Both membranes had weaker tensile strength as compared with commercial collagen membranes. They achieved sustained release of minocycline for at least 4 weeks in simulated body fluid (pH 7.4) at 37°C. Moreover, both membranes demonstrated potent sustained antibacterial effects against Staphylococcus aureus. These results suggested that the advanced collagen composite membranes containing minocycline can be exploited as novel guided tissue regeneration membranes or wound dressing by providing additional antibacterial functions.

Tooth-Supporting Hard Tissue Regeneration Using Biopolymeric Material Fabrication Strategies

The mineralized tissues (alveolar bone and cementum) are the major components of periodontal tissues and play a critical role to anchor periodontal ligament (PDL) to tooth-root surfaces. The integrated multiple tissues could generate biological or physiological responses to transmitted biomechanical forces by mastication or occlusion. However, due to periodontitis or traumatic injuries, affect destruction or progressive damage of periodontal hard tissues including PDL could be affected and consequently lead to tooth loss. Conventional tissue engineering approaches have been developed to regenerate or repair periodontium but, engineered periodontal tissue formation is still challenging because there are still limitations to control spatial compartmentalization for individual tissues and provide optimal 3D constructs for tooth-supporting tissue regeneration and maturation. Here, we present the recently developed strategies to induce osteogenesis and cementogenesis by the fabrication of 3D architectures or the chemical modifications of biopolymeric materials. These techniques in tooth-supporting hard tissue engineering are highly promising to promote the periodontal regeneration and advance the interfacial tissue formation for tissue integrations of PDL fibrous connective tissue bundles (alveolar bone-to-PDL or PDL-to-cementum) for functioning restorations of the periodontal complex.

Biodegradable engineered fiber scaffolds fabricated by electrospinning for periodontal tissue regeneration

Considering the specificity of periodontium and the unique advantages of electrospinning, this technology has been used to fabricate biodegradable tissue engineering materials for functional periodontal regeneration. For better biomedical quality, a continuous technological progress of electrospinning has been performed. Based on property of materials (natural, synthetic or composites) and additive novel methods (drug loading, surface modification, structure adjustment or 3 D technique), various novel membranes and scaffolds that could not only relief inflammation but also influence the biological behaviors of cells have been fabricated to achieve more effective periodontal regeneration. This review provides an overview of the usage of electrospinning materials in treatments of periodontitis, in order to get to know the existing research situation and find treatment breakthroughs of the periodontal diseases.

Implantable zoledronate-PLGA microcapsules ameliorate alveolar bone loss, gingival inflammation and oxidative stress in an experimental periodontitis rat model

The effect of implantable Zoledronate-PLGA microcapsules (PLGA-ZOL) in periodontitis remains unclear. In this study, we aimed to explore the potential role of PLGA-ZOL in protecting periodontitis and elucidate the underlying mechanism. A rat model of periodontitis was established by ligation the mandibular first molars, then PLGA-ZOL was implanted. The healing volume was scanned by cone-beam computed tomography. Cytokine levels in the gingival tissues were determined by ELISA and RT-PCR. Oxidative stress was indicated by detecting superoxide dismutase concentration and catalase activity. After periodontitis model was successfully established in rats, PLGA-ZOL treatment significantly attenuated alveolar bone loss, as indicated by the increased total healing volume, bone volume/tissue volume and osteoprotegerin level, as well as decreased sRANKL level. PLGA-ZOL treatment also suppressed the inflammatory activities by inhibiting pro-inflammatory cytokine production (TNF-α, IL-1β) but increasing anti-inflammatory cytokine secretion (IL-10). Furthermore, PLGA-ZOL was found to ameliorate oxidative stress in gingival tissues. In conclusion, PLGA-ZOL microcapsules ameliorate alveolar bone loss, gingival inflammation and oxidative stress in an experimental rat model of periodontitis.

Identifying Specific Combinations of Matrix Properties that Promote Controlled and Sustained Release of a Hydrophobic Drug from Electrospun Meshes

Despite advances in the development of degradable polymers for drug delivery, effective translation of drug-loaded materials is often hindered due to a poor understanding of matrix property combinations that promote controlled and sustained release. In this study, we investigated the influence of dominant factors on the release of a hydrophobic glucocorticoid dexamethasone (DEX) from electrospun meshes. Polycaprolactone meshes released 98% of the drug within 24 h, while poly(l-lactide) meshes exhibited negligible release even after 28 days despite both polymers being slow-degrading. Differences in drug-polymer interactions and drug-polymer miscibility-but neither matrix degradation nor differences in bulk hydrophobicity-influenced DEX release from these semi-crystalline matrices. Poly(d,l-lactide-co-glycolide) 50:50 meshes possessing two different fiber diameters exhibited a sequential burst and sustained release, while poly(d,l-lactide-co-glycolide) 85:15 meshes cumulatively released 26% drug in a controlled manner. Although initial drug release from these matrices was driven by differences in matrix architecture and solid-state drug solubility, release toward the later stages was influenced by a combination of fiber swelling and matrix degradation as evidenced by gross and microstructural changes to the mesh network. We suggest that drug release from polymeric matrices can be better understood via investigation of critical matrix characteristics influencing release, as well as concomitant examination of drug-polymer interactions and miscibility. Our findings offer rational matrix design criteria to achieve controlled/extended drug release for promoting sustained biological responses.