The generation of structural color from wrinkled polydimethylsiloxane (PDMS) surfaces, fabricated by plasma exposure, subjected to uni‐ and multi‐axial, and sequential strain fields is examined. The approach is based on the well‐known, mechanically‐induced, buckling instability of a supported bilayer, whereby the top glassy “skin” is formed by plasma oxidation. Surface periodicities 200 nm ≲ d ≲ 3 μm, encompassing the visible spectrum, are investigated in terms of the observed color, intensity spectrum, and color mixing from different diffraction orders, exhibiting good agreement with model predictions. By contrast with complex fabrication methods, color tunability and mechanochromic response are readily achieved by adjusting plasma and strain parameters, and by dynamically varying strain (ε ≲ 50%). Prescribed strain directionality, employing uniaxial, isotropic, gradient strain, and wave‐sum wrinkling superposition, as well as skin thickness (and thus d) and amplitude gradients, using facile and scalable fabrication approaches, yield striking spatial color variation, homogeneity, and directionality.

The incidence of periprosthetic joint infections (PJIs) is ~2% of total procedures and it is expected to rise due to an ageing population. Despite the large burden PJI has on both the individual and society, the immune response to the most commonly isolated pathogens, i.e., Staphylococcus aureus and Staphylococcus epidermidis, remains incompletely understood. In this work, we integrate the analysis of synovial fluids from patients undergoing hip and knee replacement surgery with in-vitro experimental data obtained using a newly developed platform, mimicking the environment of periprosthetic implants. We found that the presence of an implant, even in patients undergoing aseptic revisions, is sufficient to induce an immune response, which is significantly different between septic and aseptic revisions. This difference is confirmed by the presence of pro- and anti-inflammatory cytokines in synovial fluids. Moreover, we discovered that the immune response is also dependent on the type of bacteria and the topography of the implant surface. While S. epidermidis seems to be able to hide better from the attack of the immune system when cultured on rough surfaces (indicative of uncemented prostheses), S. aureus reacts differently depending on the contact surface it is exposed to. The experiments we performed in-vitro also showed a higher biofilm formation on rough surfaces compared to flat ones for both species, suggesting that the topography of the implant could influence both biofilm formation and the consequent immune response.

Breast implants are extensively employed for both reconstructive and esthetic purposes. However, the safety of breast implants with textured surfaces has been questioned, owing to a potential correlation with anaplastic large-cell lymphoma and the recurrence of breast cancer. This study investigates the immune response elicited by different prosthetic surfaces, focusing on the comparison between macrotextured and microtextured breast implants. Through the analysis of intraoperatively harvested periprosthetic fluids and cell culture experiments on surface replicas, we demonstrate that macrotextured surfaces elicit a more pronounced chronic-like activation of leucocytes and an increased release of inflammatory cytokines, in contrast to microtextured surfaces. In addition, in vitro fluorescent imaging of leucocytes revealed an accumulation of lymphocytes within the cavities of the macrotextured surfaces, indicating that the physical entrapment of these cells may contribute to their activation. These findings suggest that the topography of implant surfaces plays a significant role in promoting a chronic-like inflammatory environment, which could be a contributing factor in the development of lymphomas associated with a wide range of implantable devices.

Polyhydroxyalkanoates (PHAs) are naturally occurring polyesters with promising drug delivery applications. Their hydrophobicity enables lipophilic drug encapsulation, enhancing bioavailability but limiting colloidal stability and physiological compatibility. Surfactants crucially improve the nanoparticle dimensional stability, dispersion, wettability of hydrophobic matrices, and cellular interaction, yet conventional surfactants require additional purification and may pose physiological risks. Self-surfactant systems offer a sustainable alternative. Therefore, this research proposes a green chemical modification of PHAs to develop self-surfactant systems. Hydrophilic groups were introduced onto a poly-3-hydroxybutyrate-co-3-hydroxyhexanoate (PHBHHx) backbone via amidation using choline taurinate ([Ch][Tau]), a biocompatible ionic liquid. This approach eliminates the need for toxic reagents and complex purification. By precisely controlling the PHBHHx/[Ch][Tau] molar ratio, amphiphilic structures with varying hydrophobic tail lengths were produced, as confirmed by infrared spectroscopy and chromatographic analysis. Nanoparticles were fabricated through the emulsion-solvent evaporation method and employed to encapsulate the lipophilic and antimicrobial agent usnic acid. Dynamic light scattering highlighted the obtainment of stable colloidal suspensions with dimensions of 40-160 nm. Biological evaluations demonstrated the antimicrobial efficacy against planktonic S. aureus Newman strain and biofilm inhibition under fluidic conditions even for the unloaded nanoparticles. Additionally, the nanoparticles exhibited no cytotoxicity at concentrations ranging from 10 to 0.1 μg/mL while retaining antimicrobial activity, in contrast to the high cytotoxicity observed for free usnic acid. Overall, this approach offers a sustainable and scalable strategy to produce self-surfactant and intrinsically antimicrobial polymeric nanocarriers suitable for the systemic drug delivery of lipophilic compounds, smart implant coatings, and antibacterial topical formulations.

Periprosthetic joint infection (PJI) is a serious complication of prosthetic joint implantation, which poses a significant burden on both individuals and s

Microbial colonization and biofilm formation drive infection persistence and the spread of antimicrobial resistance, particularly under flow conditions typical of medical and natural environments. Here, we combine spontaneously buckled wrinkled topographies with microfluidic platforms to investigate the adhesion of Pseudomonas aeruginosa and Staphylococcus aureus across shear rates of 0.4-200 s⁻¹. Wrinkled surfaces with tunable wavelengths (0.5-20 μm) are fabricated and characterized using optical, atomic force, and scanning electron microscopy. Sinusoidal wrinkles with a 2 μm wavelength reduce bacterial colonization by over 70% when oriented perpendicular to flow, while folded wrinkles of 5 μm achieve more than 90% reduction across broader shear regimes and suppress biofilm formation by over 85% relative to flat controls. These topographies retain antifouling performance under pulsatile flow. This work demonstrates a scalable, chemical-free strategy for passive biofilm control through geometric surface design, enabling durable antimicrobial materials for biomedical and industrial applications.