It is demonstrated that polymer corona architecture and bacterial cell envelope properties jointly govern PDNP-bacteria interactions and photothermal antibacterial activity, providing design principles for nanomaterial-based strategies to combat AMR.
Abstract
The global rise of antimicrobial resistance (AMR) threatens the efficacy of conventional antibiotics and demands new treatment strategies beyond molecular inhibition. Nanomaterials, particularly polydopamine nanoparticles (PDNPs), offer a promising non-antibiotic platform because of their biocompatibility, facile functionalization, and intrinsic photothermal activity, which can enable spatially and temporally controlled bacterial killing. Here, we investigate how bacterial cell envelope structure and polyethylenimine (PEI) corona architecture modulate PDNP-bacteria interactions and influence photothermal antibacterial efficacy. PDNPs were functionalized with branched PEI (bPEI) of varying molecular weights to leverage its high cationic charge density and enhance nanoparticle association with bacterial surfaces. Although PEI-functionalized PDNPs exhibited similar surface zeta potentials across different bPEI molecular weights, their interactions with bacteria and resulting cytotoxic effects were molecular-weight dependent; this effect was more pronounced for Gram-negative Escherichia coli than for Gram-positive Staphylococcus epidermidis. Heat stress further amplified this response, particularly when combined with laser-induced photothermal heating of the nanoparticles. Together, these findings demonstrate that polymer corona architecture and bacterial cell envelope properties jointly govern PDNP-bacteria interactions and photothermal antibacterial activity, providing design principles for nanomaterial-based strategies to combat AMR.
Electrospun poly-based fibers functionalized with silver and gold nanoparticles demonstrated an excellent balance of safety, cytocompatibility, and antibacterial performance, making them promising candidates for biomedical applications that require both inflammation control and antimicrobial protection.
Antónia Kurillová, Saverio Caporalini, Bahareh Azimi et al.· Frontiers in Bioengineering...· 0 citations
This study explores a light‐activated antimicrobial strategy by developing hybrid nanoparticles (Cn‐TBT‐NPs) composed of the conjugated polymers Cn‐PPV and PCPDTBT, which combine photodynamic and photothermal effects to inactivate
Staphylococcus aureus
and
Escherichia coli
. Cn‑TBT‑NPs, produced by nanoprecipitation and exhibiting an average diameter of 157 nm, showed sufficient spectral overlap between the polymers to support efficient Förster resonance energy transfer (FRET), thereby enhancing reactive oxygen species (ROS) generation and light‑to‑heat conversion. Under visible light irradiation (RGB LED), the hybrid NPs promoted a population reduction of over 4 logs (99.99%) for
S. aureus
and over 3 logs (99.94%) for
E. coli
. Furthermore, they exhibited a photothermal effect, raising the temperature by 20°C in 20 min under 806 nm irradiation. Electron microscopy images confirmed lethal damage to the bacterial cell structure. These results demonstrate promising photodynamic and photothermal effects, positioning these hybrid polymeric NPs as a highly effective platform for combating bacterial infections.
Hygor Chaves, C. Caires, Laís F. Aguilera et al.· ChemistrySelect· 0 citations
Antimicrobial resistance among clinically significant Gram-negative ESKAPE pathogens continues to represent a major therapeutic challenge, underscoring the need for nanomaterial-based anti-infective platforms with robust biological performance. Polyphenol-functionalized magnetic nanoparticles may offer a promising strategy for overcoming multidrug resistance and biofilm-associated infections.
Fe
3
O
4
nanoparticles functionalized with gallic acid, curcumin, or quercetin were synthesized by
in situ
alkaline co-precipitation and characterized using XRD, FTIR, TEM, DLS, zeta potential and TGA. Their antimicrobial, antibiofilm, anti-persister, quorum sensing and efflux pump inhibitory activities were evaluated against multidrug-resistant and extensively drug-resistant clinical isolates of
Klebsiella pneumoniae, Acinetobacter baumannii
and
Pseudomonas aeruginosa
. Cytocompatibility was assessed using MTT assays.
Physicochemical and interfacial analyses confirmed the formation of polyphenol-coated Fe
3
O
4
nanomaterials, with preserved magnetite crystallinity, nanoscale dimensions, negative surface charge, and stable organic loading. In comparison with the corresponding free polyphenols, the nanoformulations exhibited an increase in antibacterial activity, with Fe
3
O
4
@gallic acid showing the most potent effect and a minimum inhibitory concentration of 16 μg/mL against
A. baumannii
. At sub-inhibitory concentrations, these materials significantly inhibited biofilm formation and diminished mature-biofilm biomass and metabolic activity by up to 78% and 85%, respectively. Notably, Fe
3
O
4
@gallic acid also decreased persister-cell burden by up to 5.0 log
10
CFU/mL, while gene-expression profiling suggested modulation of quorum-sensing and efflux-associated pathways.
These findings highlight the potential of polyphenol-functionalized Fe
3
O
4
nanomaterials as promising candidates for localized antimicrobial interventions and antibiofilm surface engineering.
Lucian-Mihai Mercan, Andreea Pîndaru, Grațiela Grădişteanu Pircalabioru et al.· Frontiers in Nanotechnology· 0 citations
Antibiotic-resistant infections remain a major barrier to wound care, motivating antimicrobial biomaterials that are effective and locally activatable. Here, we report infection-responsive iron-doped carbon dots (FeCDs) synthesized via a one-pot hydrothermal route using biocompatible iron(II) gluconate. FeCDs eradicate bacteria through synergistic dual pathways: (i) a contact-independent mechanism in which iron doping confers peroxidase-like activity to catalyze reactive oxygen species (ROS) generation in H2O2-rich infection microenvironments, amplifying localized oxidative stress; and (ii) a contact-dependent mechanism where FeCDs electrostatically bind to bacteria and drive material-bacteria interfacial electron transfer, disrupting respiratory chains and energy production. Combined experiments and molecular dynamics simulations substantiate this synergistic coupling between catalytic and bioelectronic kinetics. Consequently, FeCDs exhibit broad-spectrum antibacterial ability with a high bactericidal rate (98.91%), and significantly accelerate infected wound healing with excellent biosafety. This work advances scalable carbon-based nanozymes, and highlights respiratory electron disruption as a powerful and complementary modality for anti-infective therapy.
