NIR-activated nanosystems with self-modulated bacteria targeting for enhanced biofilm eradication and caries prevention

Application of Mesoporous Carbon-Based Highly Dispersed K-O2 Strong Lewis Base in the Efficient Catalysis of Methanol and Ethylene Carbonate

As an atom-economical reaction, the direct generation of dimethyl carbonate (DMC) and ethylene glycol (EG) via the transesterification of CH3OH and ethylene carbonate (EC) has several promising applications, but the exploration of carriers with high specific surface areas and novel heterogeneous catalysts with more basic sites remains a long-standing research challenge. For this purpose, herein, a nitrogen-doped mesoporous carbon (NMC, 439 m2/g) based K-O2 Lewis base catalyst (K-O2/NMC) with well-dispersed strongly basic sites (2.23 mmol/g, 84.5%) was designed and synthesized. The compositions and structures of NMC and K-O2/NMC were comprehensively investigated via Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption, CO2 temperature-programmed desorption, and contact angle measurements. The optimal structural configuration and electron cloud distribution of the K-O2/NMC catalyst were simulated using first-principles calculations. The electron transfer predominantly manifested as a flow from K-O to C-O/C-N, and the interatomic interactions between each atom were enhanced and exhibited a tendency for a more stable state after redistribution. Furthermore, the adsorption energies (Eads) of CH3OH at K-O-O and K-O-N sites were -1.4185 eV and -1.3377 eV, respectively, and the O atom in CH3OH exhibited a stronger adsorption tendency for the K atom at the K-O-O site. Under the optimal conditions, the EC conversion, DMC/EG selectivity, and turnover number/frequency were 80.9%, 98.6%/99.4%, and 40.5/60.8 h-1, respectively, with a reaction rate constant (k) of 0.1005 mol/(L·min). Results showed that the heterogeneous K-O2/NMC catalyst prepared herein greatly reduced the reaction cost while guaranteeing the catalytic effect, and the whole system required a lower reaction temperature (65 °C), a shorter reaction time (40 min), and a lower catalyst amount (2.0 wt % of EC). Therefore, K-O2/NMC can be used as a catalyst in different transesterification reactions.

Silver incorporated SeTe nanoparticles with enhanced photothermal and photodynamic properties for synergistic effects on anti-bacterial activity and wound healing

Bacteria invade the host's immune system, thereby inducing serious infections. Current treatments for bacterial infections mostly rely on single modalities, which cannot completely inhibit bacteria. This study evaluates the therapeutic potential of SeTe-Ag NPs, designed with excellent photo responsiveness, with a particular focus on their dual-action antibacterial effect and wound healing properties. SeTe-Ag NPs exhibited promising synergistic antibacterial effects due to their superior photothermal and photodynamic properties. The investigation records substantial zones of inhibition of bacteria, demonstrating potent antibacterial effect. Furthermore, upon the irradiation of near-infrared (NIR) light, SeTe-Ag NPs exhibit remarkable antibiofilm and wound-healing capabilities. Overall, this study shows the applications of NIR-active SeTe-Ag NPs, which serve as a versatile platform for biomedical applications.

Photochemical Strategies toward Precision Targeting against Multidrug-Resistant Bacterial Infections

Infectious diseases pose a serious threat and a substantial economic burden on global human and public health security, especially with the frequent emergence of multidrug-resistant (MDR) bacteria in clinical settings. In response to this urgent need, various photobased anti-infectious therapies have been reported lately. This Review explores and discusses several photochemical targeted antibacterial therapeutic strategies for addressing bacterial infections regardless of their antibiotic susceptibility. In contrast to conventional photobased therapies, these approaches facilitate precise targeting of pathogenic bacteria and/or infectious microenvironments, effectively minimizing toxicity to mammalian cells and surrounding healthy tissues. The highlighted therapies include photodynamic therapy, photocatalytic therapy, photothermal therapy, endogenous pigments-based photobleaching therapy, and polyphenols-based photo-oxidation therapy. This comprehensive exploration aims to offer updated information to facilitate the development of effective, convenient, safe, and alternative strategies to counter the growing threat of MDR bacteria in the future.

Dynamic covalent nano-networks comprising antibiotics and polyphenols orchestrate bacterial drug resistance reversal and inflammation alleviation

New antimicrobial strategies are urgently needed to meet the challenges posed by the emergence of drug-resistant bacteria and bacterial biofilms. This work reports the facile synthesis of antimicrobial dynamic covalent nano-networks (aDCNs) composing antibiotics bearing multiple primary amines, polyphenols, and a cross-linker acylphenylboronic acid. Mechanistically, the iminoboronate bond drives the formation of aDCNs, facilitates their stability, and renders them highly responsive to stimuli, such as low pH and high H₂O₂ levels. Besides, the representative A1B1C1 networks, composed of polymyxin B1(A1), 2-formylphenylboronic acid (B1), and quercetin (C1), inhibit biofilm formation of drug-resistant Escherichia coli, eliminate the mature biofilms, alleviate macrophage inflammation, and minimize the side effects of free polymyxins. Excellent bacterial eradication and inflammation amelioration efficiency of A1B1C1 networks are also observed in a peritoneal infection model. The facile synthesis, excellent antimicrobial performance, and biocompatibility of these aDCNs potentiate them as a much-needed alternative in current antimicrobial pipelines.

Smart dental materials for antimicrobial applications

Smart biomaterials can sense and react to physiological or external environmental stimuli (e.g., mechanical, chemical, electrical, or magnetic signals). The last decades have seen exponential growth in the use and development of smart dental biomaterials for antimicrobial applications in dentistry. These biomaterial systems offer improved efficacy and controllable bio-functionalities to prevent infections and extend the longevity of dental devices. This review article presents the current state-of-the-art of design, evaluation, advantages, and limitations of bioactive and stimuli-responsive and autonomous dental materials for antimicrobial applications. First, the importance and classification of smart biomaterials are discussed. Second, the categories of bioresponsive antibacterial dental materials are systematically itemized based on different stimuli, including pH, enzymes, light, magnetic field, and vibrations. For each category, their antimicrobial mechanism, applications, and examples are discussed. Finally, we examined the limitations and obstacles required to develop clinically relevant applications of these appealing technologies.

Topically Applied Biopolymer-Based Tri-Layered Hierarchically Structured Nanofibrous Scaffold with a Self-Pumping Effect for Accelerated Full-Thickness Wound Healing in a Rat Model

Wound healing has grown to be a significant problem at a global scale. The lack of multifunctionality in most wound dressing-based biopolymers prevents them from meeting all clinical requirements. Therefore, a multifunctional biopolymer-based tri-layered hierarchically nanofibrous scaffold in wound dressing can contribute to skin regeneration. In this study, a multifunctional antibacterial biopolymer-based tri-layered hierarchically nanofibrous scaffold comprising three layers was constructed. The bottom and the top layers contain hydrophilic silk fibroin (SF) and fish skin collagen (COL), respectively, for accelerated healing, interspersed with a middle layer of hydrophobic poly-3-hydroxybutyrate (PHB) containing amoxicillin (AMX) as an antibacterial drug. The advantageous physicochemical properties of the nanofibrous scaffold were estimated by SEM, FTIR, fluid uptake, contact angle, porosity, and mechanical properties. Moreover, the in vitro cytotoxicity and cell healing were assessed by MTT assay and the cell scratching method, respectively, and revealed excellent biocompatibility. The nanofibrous scaffold exhibited significant antimicrobial activity against multiple pathogenic bacteria. Furthermore, the in vivo wound healing and histological studies demonstrated complete wound healing in wounded rats on day 14, along with an increase in the expression level of the transforming growth factor-β1 (TGF-β1) and a decrease in the expression level of interleukin-6 (IL-6). The results revealed that the fabricated nanofibrous scaffold is a potent wound dressing scaffold, and significantly accelerates full-thickness wound healing in a rat model.

Photonics-based treatments: Mechanisms and applications in oral infectious diseases

Infectious diseases remain a serious global challenge threatening human health. Oral infectious diseases, a major neglected global problem, not only affect people's lifestyles but also have an intimate association with systemic diseases. Antibiotic therapy is a common treatment. However, the emergence of new resistance problems hindered and enhanced the complication of the treatment. Currently, antimicrobial photodynamic therapy (aPDT) has long been the topic of intense interest due to the advantage of being minimally invasive, low toxicity, and high selectivity. aPDT is also becoming increasingly popular and applied in treating oral diseases such as tooth caries, pulpitis, periodontal diseases, peri-implantitis, and oral candidiasis. Photothermal therapy (PTT), another phototherapy, also plays an important role in resisting resistant bacterial and biofilm infections. In this mini-review, we summarize the latest advances in photonics-based treatments of oral infectious diseases. The whole review is divided into three main parts. The first part focuses on photonics-based antibacterial strategies and mechanisms. The second part presents applications for photonics-based treatments of oral infectious diseases. The last part discusses present problems in current materials and future perspectives.

Dental plaque-inspired versatile nanosystem for caries prevention and tooth restoration

Dental caries is one of the most prevalent human diseases resulting from tooth demineralization caused by acid production of bacteria plaque. It remains challenges for current practice to specifically identify, intervene and interrupt the development of caries while restoring defects. In this study, inspired by natural dental plaque, a stimuli-responsive multidrug delivery system (PMs@NaF-SAP) has been developed to prevent tooth decay and promote enamel restoration. Classic spherical core-shell structures of micelles dual-loaded with antibacterial and restorative agents are self-assembled into bacteria-responsive multidrug delivery system based on the pH-cleavable boronate ester bond, followed by conjugation with salivary-acquired peptide (SAP) to endow the nanoparticle with strong adhesion to tooth enamel. The constructed PMs@NaF-SAP specifically adheres to tooth, identifies cariogenic conditions and intelligently releases drugs at acidic pH, thereby providing antibacterial adhesion and cariogenic biofilm resistance, and restoring the microarchitecture and mechanical properties of demineralized teeth. Topical treatment with PMs@NaF-SAP effectively diminishes the onset and severity of caries without impacting oral microbiota diversity or surrounding mucosal tissues. These findings demonstrate this novel nanotherapy has potential as a promising biomedical application for caries prevention and tooth defect restoration while resisting biofilm-associated diseases in a controlled manner activated by pathological bacteria.

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Nanomaterials can adhere to tooth and target acidic biofilms specifically.

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Application of caries prevention and tooth defect restoration.

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Guidance for the innovation of the existing post-defect restoration strategies.

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The multidrug delivery system exerts antibacterial and restorative abilities on demand.

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Bacteria-responsive system resists biofilm-associated diseases in a controlled manner.

Infection-responsive long-term antibacterial bone plates for open fracture therapy

The infections in open fracture induce high morbidity worldwide. Thus, developing efficient anti-infective orthopedic devices is of great significance. In this work, we designed a kind of infection-responsive long-term antibacterial bone plates. Through a facile and flexible volatilization method, a multi-aldehyde polysaccharide derivative, oxidized sodium alginate, was crosslinked with multi-amino compounds, gentamycin and gelatin, to fabricate a uniform coating on Ti bone plates via Schiff base reaction, which was followed by a secondary crosslinking process by glutaraldehyde. The double-crosslinked coating was stable under normal condition, and could responsively release gentamycin by the triggering of the acidic microenvironment caused by bacterial metabolism, owning to the pH-responsiveness of imine structure. The thickness of the coating was ranging from 22.0 μm to 63.6 μm. The coated bone plates (Ti-GOGs) showed infection-triggered antibacterial properties (>99%) and high biocompatibility. After being soaked for five months, it still possessed efficient antibacterial ability, showing its sustainable antibacterial performance. The in vivo anti-infection ability was demonstrated by an animal model of infection after fracture fixation (IAFF). At the early stage of IAFF, Ti-GOGs could inhibit the bacterial infection (>99%). Subsequently, Ti-GOGs could promote recovery of fracture of IAFF. This work provides a convenient and universal strategy for fabrication of various antibacterial orthopedic devices, which is promising to prevent and treat IAFF.

Emerging strategies in nanotechnology to treat respiratory tract infections: realizing current trends for future clinical perspectives

A boom in respiratory tract infection cases has inflicted a socio-economic burden on the healthcare system worldwide, especially in developing countries. Limited alternative therapeutic options have posed a major threat to human health. Nanotechnology has brought an immense breakthrough in the pharmaceutical industry in a jiffy. The vast applications of nanotechnology ranging from early diagnosis to treatment strategies are employed for respiratory tract infections. The research avenues explored a multitude of nanosystems for effective drug delivery to the target site and combating the issues laid through multidrug resistance and protective niches of the bacteria. In this review a brief introduction to respiratory diseases and multifaceted barriers imposed by bacterial infections are enlightened. The manuscript reviewed different nanosystems, i.e. liposomes, solid lipid nanoparticles, polymeric nanoparticles, dendrimers, nanogels, and metallic (gold and silver) which enhanced bactericidal effects, prevented biofilm formation, improved mucus penetration, and site-specific delivery. Moreover, most of the nanotechnology-based recent research is in a preclinical and clinical experimental stage and safety assessment is still challenging.

Guanidinium-Decorated Nanostructure for Precision Sonodynamic-Catalytic Therapy of MRSA-Infected Osteomyelitis

Osteomyelitis caused by methicillin-resistant Staphylococcus aureus (MRSA) biofilm infection is difficult to eradicate and can even be life-threatening. Given that the infection is persistent and deep-seated in the bone tissue, controlled and efficient treatment of osteomyelitis remains challenging. Herein, an activatable nanostructure (Au/TNT@PG) is presented for synergistic sonodynamic-catalytic therapy of MRSA-infected osteomyelitis. The Au/TNT@PG backbone is obtained by conjugating a guanidinium-rich polymer (PG), a component that penetrates the biofilm matrix, onto ultrasound (US)-absorbing gold-doped titanate nanotubes (Au/TNTs). Under deep-penetrating US irradiation, the nanocomposite generates ¹ O₂ for sonodynamic therapy and catalyzes the decomposition of endogenous H₂ O₂ into toxic •OH in the acidic infection microenvironment for catalytic therapy, leading to bacterial cell death. Its robust antibacterial effectiveness is attributable to its bacteria-capturing ability, the biofilm penetrability of positively charged guanidinium, and the subsequent synergistic effect of sonodynamic-catalytic action of Au/TNT. Such a remotely controlled approach potentiates the polarization of macrophages to M2-type while suppressing the M1-type, leading to topical inflammation resolution and enhanced osteoblast proliferation and differentiation to inhibit bone loss. Therefore, this study provides a generic nanotherapeutic approach for efficient sonodynamic-catalytic therapy with respect to osteomyelitis.