Engineering nanotubular titania with gold nanoparticles for antibiofilm enhancement and soft tissue healing promotion

A review of the advances in implant technology: accomplishments and challenges for the design of functionalized surface structures

Biomedical implants are extensively utilized to replace hard-tissue defects owing to their biocompatibility and remarkable tissue-affinity. The materials and functional design are selected based on the resultant osseointegration level and resistance to infection, and these considerations constitute the dominant research topic in this field. However, high rates of implantation failure and peri-implantitis have been reported. Current research on biomedical-implant design encompasses enhancement of the implant surface properties, such as the roughness, nano/micro topography, and hydrophilicity, along with the realization of advanced features including antibacterial properties and cell and immunomodulation regulation. This review considers the two achievements of contemporary implant manufacturing; namely, osseointegration and the realization of antibacterial properties. Present mainstream surface modifications and coatings are discussed, along with functional design technologies and achievements. The impacts of direct surface-treatment techniques and osteogenic functional coatings on osseointegration performance and antibacterial surface structures are elucidated, considering inorganic and organic coatings with antibacterial properties as well as antibiotic-releasing coatings. Furthermore, this review highlights recent advancements in physically driven antimicrobial strategies. Expanding upon existing research, future directions for implant studies are proposed, including the realization of comprehensive functionality that integrates osseointegration and antibacterial properties, as well as patient-specific design. Our study presents a comprehensive review and offers a novel perspective on the design of biomedical implants for enhanced versatility. An in-depth exploration of future research directions will also stimulate subsequent investigations.

Surface modification strategies to reinforce the soft tissue seal at transmucosal region of dental implants

Soft tissue seal around the transmucosal region of dental implants is crucial for shielding oral bacterial invasion and guaranteeing the long-term functioning of implants. Compared with the robust periodontal tissue barrier around a natural tooth, the peri-implant mucosa presents a lower bonding efficiency to the transmucosal region of dental implants, due to physiological structural differences. As such, the weaker soft tissue seal around the transmucosal region can be easily broken by oral pathogens, which may stimulate serious inflammatory responses and lead to the development of peri-implant mucositis. Without timely treatment, the curable peri-implant mucositis would evolve into irreversible peri-implantitis, finally causing the failure of implantation. Herein, this review has summarized current surface modification strategies for the transmucosal region of dental implants with improved soft tissue bonding capacities (e.g., improving surface wettability, fabricating micro/nano topographies, altering the surface chemical composition and constructing bioactive coatings). Furthermore, the surfaces with advanced soft tissue bonding abilities can be incorporated with antibacterial properties to prevent infections, and/or with immunomodulatory designs to facilitate the establishment of soft tissue seal. Finally, we proposed future research orientations for developing multifunctional surfaces, thus establishing a firm soft tissue seal at the transmucosal region and achieving the long-term predictability of dental implants.

Photocatalytic Nanocomposite Based on Titanate Nanotubes Decorated with Plasmonic Nanoparticles for Enhanced Broad-Spectrum Antibacterial Activity

Infections resulting from microorganisms pose an ongoing global public health challenge, necessitating the constant development of novel antimicrobial approaches. Utilizing photocatalytic materials to generate reactive oxygen species (ROS) presents an appealing strategy for combating microbial threats. In alignment with this perspective, sodium titanate nanotubes were prepared by scalable hydrothermal method using TiO2 and NaOH. Ag, Au, and Ag/Au-modified titanate nanotubes (TNTs) were prepared by a cost-effective and simple ion-exchange method. All samples were characterized by XRD, FT-IR, HRTEM, and DLS techniques. HRTEM images indicated that the tubular structure was preserved in all TNTs even after the replacement of Na+ with Ag+ and/or Au3+ ions. The antibacterial activity in dark and sunlight conditions was evaluated using different bacterial strains, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The results showed that while a low bacterial count (∼log 5 cells per well) was used for inoculation, the TNTs exhibited no antibacterial activity against the three bacterial strains, regardless of whether they were tested under light or dark conditions. However, the plasmonic nanoparticle-decorated TNTs showed remarkable activity in the dark. Additionally, Ag/Au-TNTs demonstrated significantly higher activity in the dark compared with either Ag-TNTs or Au-TNTs alone. Notably, under dark conditions, the Au/Ag-TNTs achieved log reductions of up to 4.5 for P. aeruginosa, 5 for S. aureus, and 3.7 for E. coli. However, when exposed to sunlight, Au/Ag-TNTs resulted in a complete reduction (log reduction ∼9) for P. aeruginosa and E. coli. The combination of two plasmonic nanoparticles (Ag/Au) decorated on the surface of TNTs showed synergetic bactericidal activity under both dark and light conditions. Ag/Au-TNTs could be explored to design surfaces that are responsive to visible light and exhibit antimicrobial properties.

The Integration of Gold Nanoparticles into Dental Biomaterials as a Novel Approach for Clinical Advancement: A Narrative Review

Gold nanoparticles (AuNPs) have gained significant attention in the biomedical field owing to their versatile properties. AuNPs can be customized by modifying their size, shape and surface characteristics. In recent years, extensive research has explored the integration of AuNPs into various dental materials, including titanium, polymethylmethacrylate (PMMA) and resin composites. This review aims to summarize the advancements in the application of modified AuNPs in dental materials and to assess their effects on related cellular processes in the dental field. Relevant articles published in English on AuNPs in association with dental materials were identified through a systematic search of the PubMed/MEDLINE, Embase, Scopus and ScienceDirect databases from January 2014 to April 2024. Future prospects for the utilization of AuNPs in the field of dentistry are surveyed.

Recent updates and feasibility of nanodrugs in the prevention and eradication of dental biofilm and its associated pathogens-A review

OBJECTIVES

Dental biofilm is one of the most prevalent diseases in humans, which is mediated by multiple microorganisms. Globally, half of the human population suffers from dental biofilm and its associated diseases. In recent trends, nano-formulated drugs are highly attractive in the treatment of dental biofilms. However, the impact of different types of nanodrugs on the dental biofilm and its associated pathogens have not been published till date. Thus, this review focuses on the recent updates, feasibility, mechanisms, limitations, and regulations of nanodrugs applications in the prevention and eradication of dental biofilm.

STUDY SELECTION, DATA AND SOURCES

A systematic search was conducted in PubMed/Google Scholar/Scopus over the past five years covering the major keywords "nanodrugs, metallic nanoparticles, metal oxide nanoparticles, natural polymers, synthetic polymers, biomaterials, dental biofilm, antibiofilm mechanism, dental pathogens", are reviewed in this study. Nearly, 100 scientific articles are selected in this relevant topic published between 2019 and 2023. Data from the selected studies dealing with nanodrugs used for biofilm treatment was qualitatively analyzed.

CONCLUSIONS

The nanodrugs such as silver nanoparticles, gold nanoparticles, selenium nanoparticles, zinc oxide nanoparticles, copper oxide nanoparticles, titanium oxide nanoparticles, hydroxyapatite nanoparticles and these inorganic nanoparticles incorporated polymer-based nanocomposites, organic/inorganic nanoparticles mediated antimicrobial photodynamic therapy exhibits an excellent antibacterial and antibiofilm activity towards dental pathogens. Finally, this review highlights that bioinspired nanodrugs will be very useful to control the dental biofilm and its associated diseases.

CLINICAL SIGNIFICANCE

Microbial influence on the oral environment is unavoidable; therefore, curing such dental biofilms and pathogens is essential for the impactful reflection of applying biocompatible treatments. In this direction, the current review explains the demand for the nanodrug in inhibiting biofilms for the effective exploration of employing treatments.

Photocatalytic Antimicrobials: Principles, Design Strategies, and Applications

Nowadays, the increasing emergence of antibiotic-resistant pathogenic microorganisms requires the search for alternative methods that do not cause drug resistance. Phototherapy strategies (PTs) based on the photoresponsive materials have become a new trend in the inactivation of pathogenic microorganisms due to their spatiotemporal controllability and negligible side effects. Among those phototherapy strategies, photocatalytic antimicrobial therapy (PCAT) has emerged as an effective and promising antimicrobial strategy in recent years. In the process of photocatalytic treatment, photocatalytic materials are excited by different wavelengths of lights to produce reactive oxygen species (ROS) or other toxic species for the killing of various pathogenic microbes, such as bacteria, viruses, fungi, parasites, and algae. Therefore, this review timely summarizes the latest progress in the PCAT field, with emphasis on the development of various photocatalytic antimicrobials (PCAMs), the underlying antimicrobial mechanisms, the design strategies, and the multiple practical antimicrobial applications in local infections therapy, personal protective equipment, water purification, antimicrobial coatings, wound dressings, food safety, antibacterial textiles, and air purification. Meanwhile, we also present the challenges and perspectives of widespread practical implementation of PCAT as antimicrobial therapeutics. We hope that as a result of this review, PCAT will flourish and become an effective weapon against pathogenic microorganisms and antibiotic resistance.

Recent Advances of Composite Nanomaterials for Antibiofilm Application

A biofilm is a microbial community formed by bacteria that adsorb on the surface of tissues or materials and is wrapped in extracellular polymeric substances (EPS) such as polysaccharides, proteins and nucleic acids. As a protective barrier, the EPS can not only prevent the penetration of antibiotics and other antibacterial agents into the biofilm, but also protect the bacteria in the biofilm from the attacks of the human immune system, making it difficult to eradicate biofilm-related infections and posing a serious threat to public health. Therefore, there is an urgent need to develop new and efficient antibiofilm drugs. Although natural enzymes (lysozyme, peroxidase, etc.) and antimicrobial peptides have excellent bactericidal activity, their low stability in the physiological environment and poor permeability in biofilms limit their application in antibiofilms. With the development of materials science, more and more nanomaterials are being designed to be utilized for antimicrobial and antibiofilm applications. Nanomaterials have great application prospects in antibiofilm because of their good biocompati-bility, unique physical and chemical properties, adjustable nanostructure, high permeability and non-proneness to induce bacterial resistance. In this review, with the application of composite nanomaterials in antibiofilms as the theme, we summarize the research progress of three types of composite nanomaterials, including organic composite materials, inorganic materials and organic-inorganic hybrid materials, used as antibiofilms with non-phototherapy and phototherapy modes of action. At the same time, the challenges and development directions of these composite nanomaterials in antibiofilm therapy are also discussed. It is expected we will provide new ideas for the design of safe and efficient antibiofilm materials.

The current status of stimuli-responsive nanotechnologies on orthopedic titanium implant surfaces

With the continuous innovation and breakthrough of nanomedical technology, stimuli-responsive nanotechnology has been gradually applied to the surface modification of titanium implants to achieve brilliant antibacterial activity and promoted osteogenesis. Regarding to the different physiological and pathological microenvironment around implants before and after surgery, these surface nanomodifications are designed to respond to different stimuli and environmental changes in a timely, efficient, and specific way/manner. Here, we focus on the materials related to stimuli-responsive nanotechnology on titanium implant surface modification, including metals and their compounds, polymer materials and other materials. In addition, the mechanism of different response types is introduced according to different activation stimuli, including magnetic, electrical, photic, radio frequency and ultrasonic stimuli, pH and enzymatic stimuli (the internal stimuli). Meanwhile, the associated functions, potential applications and developing prospect were discussion.

Current perspectives of metal-based nanomaterials as photocatalytic antimicrobial agents and their therapeutic modes of action: A review

Efforts to restrict the emergence and progression of multidrug-resistant bacterial strains should heavily involve the scientific community, including government bodies, researchers, and industries, in developing new and effective photocatalytic antimicrobial agents. Such changes warrant the modernization and upscaling of materials synthesis laboratories to support and expedite the mass production of materials at the industrial scale for the benefit of humankind and the environment. Despite the massive volume of publications reporting the potential usage of different types of metal-based nanomaterials as antimicrobial agents, reviews uncovering the similarities and differences among the various products remain lacking. This review details the basic and unique properties of metal-based nanoparticles, their use as photocatalytic antimicrobial agents, and their therapeutic modes of action. It shall be noted that compared to traditional antibiotics, the mode of action of photocatalytic metal-based nanomaterials for killing microorganisms are completely different, despite displaying promising performance against antibiotic-resistant bacteria. Besides, this review uncovers the differences in the mode of actions of metal oxide nanoparticles against different types of bacteria, as well as towards viruses. Last but not least, this review comprehensively describes previous published clinical trials and medical usages involving contemporary photocatalytic antimicrobial agents.

Surface modification of TiO2 nanoparticles with organic molecules and their biological applications

In recent years, titanium(IV) dioxide nanoparticles (TiO₂NPs) have shown promising potential in various biological applications such as antimicrobials, drug delivery, photodynamic therapy, biosensors, and tissue engineering. For employing TiO₂NPs in these fields, their nanosurface must be coated or conjugated with organic and/or inorganic agents. This modification can improve their stability, photochemical properties, biocompatibility, and even surface area for further conjugation with other molecules such as drugs, targeting molecules, polymers, etc. This review describes the organic-based modification of TiO₂NPs and their potential applications in the mentioned biological fields. In the first part of this review, around 75 recent publications (2017-2022) are mentioned on the common TiO₂NP modifiers including organosilanes, polymers, small molecules, and hydrogels, which improve the photochemical features of TiO₂NPs. In the second part of this review, we presented 149 recent papers (2020-2022) about the use of modified TiO₂NPs in biological applications, in which specific bioactive modifiers are introduced in this part with their advantages. In this review, the following information is presented: (1) the common organic modifiers for TiO₂NPs, (2) biologically important modifiers and their benefits, and (3) recent publications on biological studies on the modified TiO₂NPs with their achievements. This review shows the paramount significance of the organic-based modification of TiO₂NPs to enhance their biological effectiveness, paving the way toward the development of advanced TiO₂-based nanomaterials in nanomedicine.

Antibacterial Properties of Gold Nanoparticles in the Modification of Medical Implants: A Systematic Review

The widespread occurrence of bacterial infections and their increased resistance to antibiotics has led to the development of antimicrobial coatings for multiple medical implants. Owing to their desirable properties, gold nanoparticles (AuNPs) have been developed as antibacterial agents. This systematic investigation sought to analyze the antibacterial effects of implant material surfaces modified with AuNPs. The data from 27 relevant studies were summed up. The included articles were collected from September 2011 to September 2021. According to the retrieved literature, we found that medical implants modified by AuNPs have good antibacterial effects against gram-positive and gram-negative bacteria, and the antibacterial effects would be improved by near-infrared (NIR) radiation.

Gold nanoparticle decoration potentiate the antibacterial enhancement of TiO2 nanotubes via sonodynamic therapy against peri-implant infections

Inflammatory damage from bacterial biofilms usually causes the failure of tooth implantation. A promising solution for this challenge is to use an implant surface with a long-term, in-depth and efficient antibacterial feature. In this study, we developed an ultrasound-enhanced antibacterial implant surface based on Au nanoparticle modified TiO2 nanotubes (AuNPs-TNTs). As an artificial tooth surface, films based on AuNPs-TNTs showed excellent biocompatibility. Importantly, compared to bare titania surface, a larger amount of reactive oxygen radicals was generated on AuNPs-TNTs under an ultrasound treatment. For a proof-of-concept application, Porphyromonas gingivalis (P. gingivalis) was used as the model bacteria; the as-proposed AuNPs-TNTs exhibited significantly enhanced antibacterial activity under a simple ultrasound treatment. This antibacterial film offers a new way to design the surface of an artificial implant coating for resolving the bacterial infection induced failure of dental implants.

Titanate nanoribbon-based nanobiohybrid for potential applications in regenerative medicine

Nanoparticles capable of mimicking natural tissues represent a major technological advancement in regenerative medicine. In this pilot study, the development of a new nanohybrid composed of titanate nanoribbons to mimic the extracellular matrix is reported. During the first phase, nanoribbons were synthesized by hydrothermal treatment. Subsequently, titanate nanoribbons were functionalized by heterobifunctional polyethylene-glycol (PEG) to graft type I collagen on their surface. Biological properties of this new nanobiohybrid such as cytotoxicity to cardiac cells and platelet aggregation ability were evaluated. The so-formed nanobiohybrid permits cellular adhesion and proliferation favoring fine cardiac tissue healing and regeneration.

Titanate nanoribbons functionalized by heterobifunctional polymer and type I collagen for cellular adhesion and proliferation. This new nanobiohybrid affected neither cytotoxicity nor platelet aggregation ability.

Influence of Anodized Titanium Surfaces on the Behavior of Gingival Cells in Contact with: A Systematic Review of In Vitro Studies

Electrochemically anodized (EA) surfaces promise enhanced biological properties and may be a solution to ensure a seal between peri-implant soft tissues and dental transmucosal components. However, the interaction between the modified nano-structured surface and the gingival cells needs further investigation. The aim of this systematic review is to analyze the biological response of gingival cells to EA titanium surfaces in in vitro studies with a score-based reliability assessment. A protocol aimed at answering the following focused question was developed: “How does the surface integrity (e.g., topography and chemistry) of EA titanium influence gingival cell response in in vitro studies?”. A search in three computer databases was performed using keywords. A quality assessment of the studies selected was performed using the SciRAP method. A total of 14 articles were selected from the 216 eligible papers. The mean reporting and the mean methodologic quality SciRAP scores were 87.7 ± 7.7/100 and 77.8 ± 7.8/100, respectively. Within the limitation of this review based on in vitro studies, it can be safely speculated that EA surfaces with optimal chemical and morphological characteristics enhance gingival fibroblast response compared to conventional titanium surfaces. When EA is combined with functionalization, it also positively influences gingival epithelial cell behavior.

Influence of Titania Nanotubes Diameter on Its Antibacterial Efficacy against Periodontal Pathogens: An In vitro Analysis

Background

Peri implant infection in dental implantology is a frequently encountered clinical problem. Titania nanotubes (TNTs) are recent improvement in surface characterization, showing promising results.

Aim

The nanosurface parameter tweaking has been implicated with profound change in the microbiological and biological response. Hence, it was proposed that alteration in the nanotube diameter could have positive influence in its antibacterial activity against salient periodontal pathogens.

Materials and Methods

Commercially, pure titanium discs of 8-mm diameter and 1.5-mm thickness were prepared. Polished titanium discs were used as control (Group A). Vertically oriented, structured TNTs were fabricated by anodization technique and grouped as B and C, having nanotube diameter, 40 and 80 nm subsequently. The surface characterizations of the samples were done by scanning electron microscope analysis. The antibacterial activity was evaluated with the bacterial colony counting method, at 24 h, 72 h, and 1-week intervals.

Statistical Analysis

The one-way analysis of variance and Tukey's honest significance post hoc test were employed to assess the statistical significance.

Results

The 80 nm nanotubes showed better antibacterial activity comparatively, at all three-time intervals investigated.

Conclusion

The optimal TNT diameter of 80 nm was the most effective from an antimicrobial stand point of view.

Double-edged sword: Therapeutic efficacy versus toxicity evaluations of doped titanium implants

Titanium-based orthopaedic/dental implants modified with various metal-doping strategies can enhance local therapy and bioactivity. Intentional or unintentional (because of loading and wear) release of metal ions/nanoparticles (NPs) from metal-doped implants can be therapeutic or cause adverse local tissue reactions, compromising long-term survival. Strategies to incorporate metals into implants, such as superficial or deep loading inside nano-engineered surfaces, including nanotubes, and the physiochemical characteristics of the released species significantly influence both their therapeutic and cytotoxic potential. In this review, we compare and contrast this 'double-edged sword' to arrive at an improved understanding of metal-doped implants to enable controlled therapy while minimising cytotoxicity concerns.