In Situ Microscopic Studies on the Interaction of Multi-Principal Element Nanoparticles and Bacteria

Scalable and Versatile Metal Ion Solidificated Alginate Hydrogel for Skin Wound Infection Therapy

Bacterial infections in wounds continue to be a major challenge in clinical settings worldwide and represent a significant threat to human health. This work proposes novel expandable and versatile methods for solidifying sodium alginate (SA) with metal ions (such as Fe3+, Co2+, Ni2+, Cu2+, and Zn2+) to create Metal-Alginate (M-Alg) hydrogel with adjustable morphology, composition, and microstructure. It conforms to the wound site, protects against second infection, reduces inflammation, and promotes the healing of infected wounds. Among these hydrogels, Cu-Alginate (Cu-Alg) shows excellent sterilization effect and good efficacy against both gram-positive and gram-negative bacteria, including multidrug-resistant (MDR) strains such as Methicillin-resistant Staphylococcus aureus (MRSA) and Carbapenem-resistant Klebsiella pneumoniae (CRKP) due to its dual antibacterial mechanisms: contact-killing and reactive oxygen species (ROS) burst. Importantly, it exhibits low cytotoxicity and biodegradability. This simple and cost-effective gel-based system has the potential to introduce an innovative approach to the management of wound infection and offers promising new perspectives for the advancement of wound care practice.

Customized Lanthanide Nanobiohybrids for Noninvasive Precise Phototheranostics of Pulmonary Biofilm Infection

A noninvasive strategy for in situ diagnosis and precise treatment of bacterial biofilm infections is highly anticipated but still a great challenge. Currently, no in vivo biofilm-targeted theranostic agent is available. Herein, we fabricated intelligent theranostic alginate lyase (Aly)-NaNdF4 nanohybrids with a 220 nm sunflower-like structure (NaNdF4@DMS-Aly) through an enrichment-encapsulating strategy, which exhibited excellent photothermal conversion efficiency and the second near-infrared (NIR-II) luminescence. Benefiting from the site-specific targeting and biofilm-responsive Aly release from NaNdF4@DMS-Aly, we not only enabled noninvasive diagnosis but also realized Aly-photothermal synergistic therapy and real-time evaluation of therapeutic effect in mice models with Pseudomonas aeruginosa biofilm-induced pulmonary infection. Furthermore, such nanobiohybrids with a sheddable siliceous shell are capable of delaying the NaNdF4 dissolution and biodegradation upon accomplishing the therapy, which is highly beneficial for the biosafety of theranostic agents.

Bioinspired Superhydrophobic Nanocoating Based on Polydopamine and Nanodiamonds to Mitigate Bacterial Attachment to Polyvinyl Chloride Surfaces in Food Industry Environments

Polyvinyl chloride (PVC) is commonly utilized as a food-contact surface by the food industry for processing and storage purposes due to its durability, ease of fabrication, and cost-effectiveness. Herein, we report a composite coating for the superhydrophobization of PVC without the use of polyfluoroalkyl chemistry. This coating rendered the PVC superhydrophobic, exhibiting a static water contact angle of 151.9 ± 0.7° and a contact angle hysteresis of only 3.1 ± 1.0°. The structure of this composite coating, consisting of polydopamine, nanodiamonds, and an alkyl silane, was investigated by utilizing both scanning electron microscopy and atomic force microscopy. Surface chemistry was probed using attenuated total reflectance-Fourier transform infrared, and the surface wetting behavior was thoroughly characterized using both static and dynamic water contact angle measurements. It was demonstrated that the superhydrophobic PVC was cleanable using a food-grade surfactant, becoming wet in contact with high concentration surfactant solutions, but regaining its nonwetting property upon rinsing with water. It was demonstrated that the coating produced a 2.1 ± 0.1 log10 reduction (99.2%) in the number of Escherichia coli O157:H7 cells and a 2.2 ± 0.1 log10 reduction (99.3%) in the number of Salmonella enterica Typhimurium cells that were able to adsorb onto PVC surfaces over a 24 h period. The use of this fluorine-free superhydrophobic coating on PVC equipment, such as conveyor belts within food production facilities, may help to mitigate bacterial cross-contamination and curb the spread of foodborne illnesses.

Nanotechnology's frontier in combatting infectious and inflammatory diseases: prevention and treatment

Inflammation-associated diseases encompass a range of infectious diseases and non-infectious inflammatory diseases, which continuously pose one of the most serious threats to human health, attributed to factors such as the emergence of new pathogens, increasing drug resistance, changes in living environments and lifestyles, and the aging population. Despite rapid advancements in mechanistic research and drug development for these diseases, current treatments often have limited efficacy and notable side effects, necessitating the development of more effective and targeted anti-inflammatory therapies. In recent years, the rapid development of nanotechnology has provided crucial technological support for the prevention, treatment, and detection of inflammation-associated diseases. Various types of nanoparticles (NPs) play significant roles, serving as vaccine vehicles to enhance immunogenicity and as drug carriers to improve targeting and bioavailability. NPs can also directly combat pathogens and inflammation. In addition, nanotechnology has facilitated the development of biosensors for pathogen detection and imaging techniques for inflammatory diseases. This review categorizes and characterizes different types of NPs, summarizes their applications in the prevention, treatment, and detection of infectious and inflammatory diseases. It also discusses the challenges associated with clinical translation in this field and explores the latest developments and prospects. In conclusion, nanotechnology opens up new possibilities for the comprehensive management of infectious and inflammatory diseases.

APTES-mediated Cu2(OH)3(NO3) nanomaterials on the surface of silicone catheters for abscess

Metal-based nanomaterials have remarkable bactericidal effects; however, their toxicity cannot be disregarded. To address this concern, we developed a simple synthesis route for antibacterial catheters using metal-based nanomaterials to reduce toxicity while harnessing their excellent bactericidal properties. The grafting agent (3-aminopropyl)triethoxysilane (APTES) forms -NH2 groups on the catheter surface, onto which copper ions form a nanomaterial complex known as Cu2(OH)3(NO3) (defined as SA-Cu). The synthesized SA-Cu exhibited outstanding contact antibacterial effects, as observed through scanning electron microscopy (SEM), which revealed cell membrane crumbing and bacterial rupture on the catheter surface. Furthermore, SA-Cu exhibited excellent biosafety characteristics, as evidenced by the cell counting kit-8 (CCK-8) assay, which showed no significant cytotoxicity. SA-Cu demonstrated sustained antimicrobial capacity, with in vivo experiments demonstrating over 99% bactericidal efficacy against methicillin-resistant Staphylococcus aureus (MRSA) for two weeks. The transcriptome sequencing results suggested that SA-Cu may exert its bactericidal effects by interfering with histidine and purine metabolism in MRSA. This study presents a straightforward method for synthesizing antimicrobial silicone catheters containing copper nanomaterials using copper ions.

Unraveling chemical processes during nanoparticle synthesis with liquid phase electron microscopy and correlative techniques

Liquid phase transmission electron microscopy (LPTEM) has enabled unprecedented direct real time imaging of physicochemical processes during solution phase synthesis of metallic nanoparticles. LPTEM primarily provides images of nanometer scale, and sometimes atomic scale, metal nanoparticle crystallization processes, but provides little chemical information about organic surface ligands, metal-ligand complexes and reaction intermediates, and redox reactions. Likewise, complex electron beam-solvent interactions during LPTEM make it challenging to pinpoint the chemical processes, some involving exotic highly reactive radicals, impacting nanoparticle formation. Pairing LPTEM with correlative solution synthesis, ex situ chemical analysis, and theoretical modeling represents a powerful approach to gain a holistic understanding of the chemical processes involved in nanoparticle synthesis. In this feature article, we review recent work by our lab and others that has focused on elucidating chemical processes during nanoparticle synthesis using LPTEM and correlative chemical characterization and modeling, including mass and optical spectrometry, fluorescence microscopy, solution chemistry, and reaction kinetic modeling. In particular, we show how these approaches enable investigating redox chemistry during LPTEM, polymeric and organic capping ligands, metal deposition mechanisms on plasmonic nanoparticles, metal clusters and complexes, and multimetallic nanoparticle formation. Future avenues of research are discussed, including moving beyond electron beam induced nanoparticle formation by using light and thermal stimuli during LPTEM. We discuss prospects for real time LPTEM imaging and online chemical analysis of reaction intermediates using microfluidic flow reactors.