Combining Coaxial Electrospinning and 3D Printing: Design of Biodegradable Bilayered Membranes with Dual Drug Delivery Capability for Periodontitis Treatment

Hierarchical Chitin Nanocrystal-Based 3D Printed Dual-Layer Membranes Hydrogels: A Dual Drug Delivery Nano-Platform for Periodontal Tissue Regeneration

Periodontitis, a prevalent chronic inflammatory disease caused by bacteria, poses a significant challenge to current treatments by merely slowing their progression. Herein, we propose an innovative solution in the form of hierarchical nanostructured 3D printed bilayer membranes that serve as dual-drug delivery nanoplatforms and provide scaffold function for the regeneration of periodontal tissue. Nanocomposite hydrogels were prepared by combining lipid nanoparticle-loaded grape seed extract and simvastatin, as well as chitin nanocrystals, which were then 3D printed into a bilayer membrane that possesses antimicrobial properties and multiscale porosity for periodontal tissue regeneration. The constructs exhibited excellent mechanical properties by adding chitin nanocrystals and provided a sustained release of distinct drugs over 24 days. We demonstrated that the bilayer membranes are cytocompatible and have the ability to induce bone-forming markers in human mesenchymal stem cells, while showing potent antibacterial activity against pathogens associated with periodontitis. In vivo studies further confirmed the efficacy of bilayer membranes in enhancing alveolar bone regeneration and reducing inflammation in a periodontal defect model. This approach suggests promising avenues for the development of implantable constructs that not only combat infections, but also promote the regeneration of periodontal tissue, providing valuable insights into advanced periodontitis treatment strategies.

Biofabrication Strategies for Oral Soft Tissue Regeneration

Gingival recession, a prevalent condition affecting the gum tissues, is characterized by the exposure of tooth root surfaces due to the displacement of the gingival margin. This review explores conventional treatments, highlighting their limitations and the quest for innovative alternatives. Importantly, it emphasizes the critical considerations in gingival tissue engineering leveraging on cells, biomaterials, and signaling factors. Successful tissue-engineered gingival constructs hinge on strategic choices such as cell sources, scaffold design, mechanical properties, and growth factor delivery. Unveiling advancements in recent biofabrication technologies like 3D bioprinting, electrospinning, and microfluidic organ-on-chip systems, this review elucidates their precise control over cell arrangement, biomaterials, and signaling cues. These technologies empower the recapitulation of microphysiological features, enabling the development of gingival constructs that closely emulate the anatomical, physiological, and functional characteristics of native gingival tissues. The review explores diverse engineering strategies aiming at the biofabrication of realistic tissue-engineered gingival grafts. Further, the parallels between the skin and gingival tissues are highlighted, exploring the potential transfer of biofabrication approaches from skin tissue regeneration to gingival tissue engineering. To conclude, the exploration of innovative biofabrication technologies for gingival tissues and inspiration drawn from skin tissue engineering look forward to a transformative era in regenerative dentistry with improved clinical outcomes.

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.

Engineering periodontal tissue interfaces using multiphasic scaffolds and membranes for guided bone and tissue regeneration

Periodontal diseases are one of the greatest healthcare burdens worldwide. The periodontal tissue compartment is an anatomical tissue interface formed from the periodontal ligament, gingiva, cementum, and bone. This multifaceted composition makes tissue engineering strategies challenging to develop due to the interface of hard and soft tissues requiring multiphase scaffolds to recreate the native tissue architecture. Multilayer constructs can better mimic tissue interfaces due to the individually tuneable layers. They have different characteristics in each layer, with modulation of mechanical properties, material type, porosity, pore size, morphology, degradation properties, and drug-releasing profile all possible. The greatest challenge of multilayer constructs is to mechanically integrate consecutive layers to avoid delamination, especially when using multiple manufacturing processes. Here, we review the development of multilayer scaffolds that aim to recapitulate native periodontal tissue interfaces in terms of physical, chemical, and biological characteristics. Important properties of multiphasic biodegradable scaffolds are highlighted and summarised, with design requirements, biomaterials, and fabrication methods, as well as post-treatment and drug/growth factor incorporation discussed.

3D-Printed Antibacterial Scaffolds for the Regeneration of Alveolar Bone in Severe Periodontitis

Current clinical treatment of periodontitis alleviates periodontal symptoms and helps to keep the disease under control for extended periods. Despite this, a significant destruction of the tooth's underlying bone tissue often takes place progressively. Herein, we present a two-way therapeutic approach for local delivery of antibacterial agents and bone tissue regeneration, incorporating ~1% w/w tetracycline hydrochloride (TCH) into a 3D-printed scaffold composed of poly(ε-caprolactone) (PCL). Samples were assessed for their morphological, physicochemical, pharmacokinetic, and antibacterial properties. Furthermore, osteoprecursor cells (MC3T3-E1) were employed to evaluate the osteoinductive potential of the drug-loaded scaffolds. Cell proliferation, viability, and differentiation were determined on all cell-seeded scaffolds. At the end of the culture, PCL-TCH scaffolds promoted abundant collagen organic matrix, demonstrating augmented alkaline phosphatase (ALP) activity and areas of accumulated mineralised bone tissue, despite their belayed cell proliferation. Based on the observed effectiveness of the PCL-TCH scaffolds to inhibit Staphylococcus aureus, these constructs could serve as an alternative bioactive implant that supports bacterial inhibition and favours a 3D microenvironment for bone tissue regeneration in severe periodontitis.

Recent Progress in Stimuli-Responsive Antimicrobial Electrospun Nanofibers

Electrospun nanofibrous membranes have garnered significant attention in antimicrobial applications, owing to their intricate three-dimensional network that confers an interconnected porous structure, high specific surface area, and tunable physicochemical properties, as well as their notable capacity for loading and sustained release of antimicrobial agents. Tailoring polymer or hybrid-based nanofibrous membranes with stimuli-responsive characteristics further enhances their versatility, enabling them to exhibit broad-spectrum or specific activity against diverse microorganisms. In this review, we elucidate the pivotal advancements achieved in the realm of stimuli-responsive antimicrobial electrospun nanofibers operating by light, temperature, pH, humidity, and electric field, among others. We provide a concise introduction to the strategies employed to design smart electrospun nanofibers with antimicrobial properties. The core section of our review spotlights recent progress in electrospun nanofiber-based systems triggered by single- and multi-stimuli. Within each stimulus category, we explore recent examples of nanofibers based on different polymers and antimicrobial agents. Finally, we delve into the constraints and future directions of stimuli-responsive nanofibrous materials, paving the way for their wider application spectrum and catalyzing progress toward industrial utilization.

Integration of 3D Printing-Coelectrospinning: Concept Shifting in Biomedical Applications

Porous structures with sizes between the submicrometer and nanometer scales can be produced using efficient and adaptable electrospinning technology. However, to approximate desirable structures, the construction lacks mechanical sophistication and conformance and requires three-dimensional solitary or multifunctional structures. The diversity of high-performance polymers and blends has enabled the creation of several porous structural conformations for applications in advanced materials science, particularly in biomedicine. Two promising technologies can be combined, such as electrospinning with 3D printing or additive manufacturing, thereby providing a straightforward yet flexible technique for digitally controlled shape-morphing fabrication. The hierarchical integration of configurations is used to imprint complex shapes and patterns onto mesostructured, stimulus-responsive electrospun fabrics. This technique controls the internal stresses caused by the swelling/contraction mismatch in the in-plane and interlayer regions, which, in turn, controls the morphological characteristics of the electrospun membranes. Major innovations in 3D printing, along with additive manufacturing, have led to the production of materials and scaffold systems for tactile and wearable sensors, filtration structures, sensors for structural health monitoring, tissue engineering, biomedical scaffolds, and optical patterning. This review discusses the synergy between 3D printing and electrospinning as a constituent of specific microfabrication methods for quick structural prototypes that are expected to advance into next-generation constructs. Furthermore, individual techniques, their process parameters, and how the fabricated novel structures are applied holistically in the biomedical field have never been discussed in the literature. In summary, this review offers novel insights into the use of electrospinning and 3D printing as well as their integration for cutting-edge applications in the biomedical field.

Are Local Drug Delivery Systems a Challenge in Clinical Periodontology?

Placing antimicrobial treatments directly in periodontal pockets is an example of the local administration of antimicrobial drugs to treat periodontitis. This method of therapy is advantageous since the drug concentration after application far surpasses the minimum inhibitory concentration (MIC) and lasts for a number of weeks. As a result, numerous local drug delivery systems (LDDSs) utilizing various antibiotics or antiseptics have been created. There is constant effort to develop novel formulations for the localized administration of periodontitis treatments, some of which have failed to show any efficacy while others show promise. Thus, future research should focus on the way LDDSs can be personalized in order to optimize future clinical protocols in periodontal therapy.

Agro-Industrial Plant Proteins in Electrospun Materials for Biomedical Application

Plant proteins are receiving a lot of attention due to their abundance in nature, customizable properties, biodegradability, biocompatibility, and bioactivity. As a result of global sustainability concerns, the availability of novel plant protein sources is rapidly growing, while the extensively studied ones are derived from byproducts of major agro-industrial crops. Owing to their beneficial properties, a significant effort is being made to investigate plant proteins' application in biomedicine, such as making fibrous materials for wound healing, controlled drug release, and tissue regeneration. Electrospinning technology is a versatile platform for creating nanofibrous materials fabricated from biopolymers that can be modified and functionalized for various purposes. This review focuses on recent advancements and promising directions for further research of an electrospun plant protein-based system. The article highlights examples of zein, soy, and wheat proteins to illustrate their electrospinning feasibility and biomedical potential. Similar assessments with proteins from less-represented plant sources, such as canola, pea, taro, and amaranth, are also described.

Biphasic drug release from electrospun structures

INTRODUCTION

Biphasic release, as a special drug-modified release profile that combines immediate and sustained release, allows fast therapeutic action and retains blood drug concentration for long periods. Electrospun nanofibers, particularly those with complex nanostructures produced by multi-fluid electrospinning processes, are potential novel biphasic drug delivery systems (DDSs).

AREAS COVERED

This review summarizes the most recent developments in electrospinning and related structures. In this review, the role of electrospun nanostructures in biphasic drug release was comprehensively explored. These electrospun nanostructures include monolithic nanofibers obtained through single-fluid blending electrospinning, core-shell and Janus nanostructures prepared via bifluid electrospinning, three-compartment nanostructures obtained via trifluid electrospinning, nanofibrous assemblies obtained through the layer-by-layer deposition of nanofibers, and the combined structure of electrospun nanofiber mats with casting films. The strategies and mechanisms through which complex structures facilitate biphasic release were analyzed.

EXPERT OPINION

Electrospun structures can provide many strategies for the development of biphasic drug release DDSs. However, many issues such as the scale-up productions of complex nanostructures, the in vivo verification of the biphasic release effects, keeping pace with the developments of multi-fluid electrospinning, drawing support from the state-of-the-art pharmaceutical excipients, and the combination with traditional pharmaceutical methods need to be addressed for real applications.

Recent Advances on Electrospun Nanofibers for Periodontal Regeneration

Periodontitis is an inflammatory infection caused by bacterial plaque accumulation that affects the periodontal tissues. Current treatments lack bioactive signals to induce tissue repair and coordinated regeneration of the periodontium, thus alternative strategies are needed to improve clinical outcomes. Electrospun nanofibers present high porosity and surface area and are able to mimic the natural extracellular matrix, which modulates cell attachment, migration, proliferation, and differentiation. Recently, several electrospun nanofibrous membranes have been fabricated with antibacterial, anti-inflammatory, and osteogenic properties, showing promising results for periodontal regeneration. Thus, this review aims to provide an overview of the current state of the art of these nanofibrous scaffolds in periodontal regeneration strategies. First, we describe the periodontal tissues and periodontitis, as well as the currently available treatments. Next, periodontal tissue engineering (TE) strategies, as promising alternatives to the current treatments, are addressed. Electrospinning is briefly explained, the characteristics of electrospun nanofibrous scaffolds are highlighted, and a detailed overview of electrospun nanofibers applied to periodontal TE is provided. Finally, current limitations and possible future developments of electrospun nanofibrous scaffolds for periodontitis treatment are also discussed.

Optimal delivery of poorly soluble drugs using electrospun nanofiber technology: Challenges, state of the art, and future directions

Poor aqueous solubility of both, existing drug molecules and those which are currently in the developmental stage, have posed a great challenge to pharmaceutical scientists because they often exhibit poor dissolution behavior and subsequent poor and erratic bioavailability. This has triggered extensive research to explore nanotechnology-based technology platforms for possible rescue. Recently, nanofibers have been exploited widely for diverse biomedical applications including for drug delivery. Electrospun nanofibers are capable of preserving the homogeneously loaded therapeutic agents in amorphous state potentialy impairing devitrification. The present review aims at providing an overview of the various key factors that affect the electrospinning process and characteristics of the nanofibers while fabrication of drug loaded nanofibers for poorly soluble drug candidates. The review explores various methodological advancements in the electrospinning process and set-ups for production scale-up. The various types of electrospun nanofibers (like simple matrix, core-sheath, Janus, and inclusion complex nanofibers) that have been exploited for the delivery of poorly soluble drugs are also critically assessed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

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.

3D Printed and Bioprinted Membranes and Scaffolds for the Periodontal Tissue Regeneration: A Narrative Review

Numerous technologies and materials were developed with the aim of repairing and reconstructing the tissue loss in patients with periodontitis. Periodontal guided bone regeneration (GBR) and guided tissue regeneration (GTR) involves the use of a membrane which prevents epithelial cell migration, and helps to maintain the space, creating a protected area in which tissue regeneration is favored. Over the time, manufacturing procedures of such barrier membranes followed important improvements. Three-dimensional (3D) printing technology has led to major innovations in periodontal regeneration methods, using technologies such as inkjet printing, light-assisted 3D printing or micro-extrusion. Besides the 3D printing of monophasic and multi-phasic scaffolds, bioprinting and tissue engineering have emerged as innovative technologies which can change the way we see GTR and GBR.

Tuning the Drug Release from Antibacterial Polycaprolactone/Rifampicin-Based Core-Shell Electrospun Membranes: A Proof of Concept

The employment of coaxial fibers for guided tissue regeneration can be extremely advantageous since they allow the functionalization with bioactive compounds to be preserved and released with a long-term efficacy. Antibacterial coaxial membranes based on poly-ε-caprolactone (PCL) and rifampicin (Rif) were synthesized here, by analyzing the effects of loading the drug within the core or on the shell layer with respect to non-coaxial matrices. The membranes were, therefore, characterized for their surface properties in addition to analyzing drug release, antibacterial efficacy, and biocompatibility. The results showed that the lower drug surface density in coaxial fibers hinders the interaction with serum proteins, resulting in a hydrophobic behavior compared to non-coaxial mats. The air-plasma treatment increased their hydrophilicity, although it induced rifampicin degradation. Moreover, the substantially lower release of coaxial fibers influenced the antibacterial efficacy, tested against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Indeed, the coaxial matrices were inhibitory and bactericidal only against S. aureus, while the higher release from non-coaxial mats rendered them active even against E. coli. The biocompatibility of the released rifampicin was assessed too on murine fibroblasts, revealing no cytotoxic effects. Hence, the presented coaxial system should be further optimized to tune the drug release according to the antibacterial effectiveness.