Biointerphases最新文献

Mollusks, and their particularly diverse class Gastropoda, owe much of their ecological success due to the evolution of their radula-a specialized feeding apparatus. This structure, composed of a chitinous membrane and sometimes mineralized teeth, plays a critical role in food acquisition and processing across a wide range of habitats. The radula's morphology, material composition, and mechanical properties exhibit remarkable diversity and functional optimization, shaped by millions of years of evolutionary refinement. Adaptive variations in tooth shape, composite material content (often rich in iron, calcium, silicon, or other elements), mechanical properties, and coordinated interaction among radular components enable mollusks to withstand strong contact forces, minimize structural failure and tooth wear, and thrive in distinct ecological niches. This review synthesizes current insights into the structure and mechanical properties of the radula teeth, highlighting its adaptations to the preferred ingesta and the functional principles of the teeth. In the course of adaptation to similar physical constraints of the ingesta, different solutions evolved independently. Besides main aspects interesting for ecological research and organismic biology, the radula's structural intelligence and efficiency present a rich source of inspiration for biomimetic innovation.

Lyme disease, caused by the bacterium Borrelia burgdorferi (B. burgdorferi), is a significant public health concern in North America, with approximately 500 000 cases reported annually in the United States. The dissemination of B. burgdorferi from the initial tick bite site to various tissues is facilitated by surface adhesins that bind to extracellular matrix proteins such as fibronectin (Fn). This study investigates the binding dynamics of B. burgdorferi surface proteins RevA, BBK32, BmpA, OspA, FlaB, and OspC to Fn using atomic force microscopy-based single-molecule force spectroscopy. Our results demonstrate that RevA and BBK32 form strong, stable bonds with Fn, highlighting their roles as key mediators of host-cell attachment. By quantifying the rupture forces and kinetic parameters of these interactions, we provide a deeper understanding of B. burgdorferi adhesion mechanics and offer insights into potential therapeutic strategies targeting early bacterial attachment.

As the body's largest organ and primary protective barrier, skin is critical for maintaining physiological homeostasis. Severe skin injuries pose a major global healthcare challenge, with hundreds of thousands of annual deaths attributed to limited transplantable skin availability. 3D bioprinting has emerged as a revolutionary approach to fabricate biomimetic, anatomically precise skin constructs. This review summarizes the research progress of 3D bioprinting in skin structural and functional regeneration: it systematically assesses five core bioprinting technologies (extrusion, inkjet, stereolithography, laser-induced forward transfer, and in situ printing) along with their advantages and limitations in skin fabrication; outlines advancements in skin-specific bioinks (biomaterials, skin cells, growth factors and medicines) and their regulatory roles in regeneration; and discusses achievements and challenges in reconstructing skin vasculature, and pigmentation. Finally, current bottlenecks and future directions for achieving complete structural and functional skin regeneration via 3D bioprinting are comprehensively addressed.

Hydrolytic and enzymatic degradation of linear segmented polyurethanes with differing compositions were studied by atomic force microscopy and time-of-flight secondary ion mass spectroscopy. Poly (ester urethane urea)s (PEUUs) with two different molecular ratios of polycaprolactone diol (PCL) soft segments and L-lysine diisocyanate/hydrazine hard segments were exposed to aqueous conditions (water or phosphate buffered saline), and the changes in their surface chemistry and morphology were studied. It was found that polymer surface roughness in aqueous conditions is significantly affected by its bulk composition. After soaking in an aqueous buffer solution, the surface of PEUU with higher PCL concentration became significantly rougher compared to PEUU with lower PCL concentration. This surface roughening can be attributed to PCL lost from the surface during hydrolytic degradation. Despite the surface roughness changes, the rate of the hydrolytic degradation of PEUUs was found to be independent of bulk polymer composition. Enzymatic degradation of a linear segmented PEUU containing an oligopeptide segment [poly(peptide urethane urea) (PPUU)] in a collagenase solution was also investigated. The PPUU oligopeptide segment contained proline, hydroxyproline, and glycine amino acids. In a collagenase solution, the PPUU polymer exhibited a significantly higher degradation rate and surface roughness compared to a PEUU polymer that did not contain the oligopeptide segment.

High-speed atomic force microscopy (HS-AFM) was used to directly visualize the single-molecule adsorption dynamics of fibrinogen (FG) and bovine serum albumin (BSA) on atomically smooth mica and on silica nanoparticle (SiNP) coatings. By capturing the motion of individual proteins against a static background, HS-AFM enables the resolution of key dynamic processes, including surface diffusion, conformational adaptation, binding and unbinding events, and interfacial fluctuations on nanostructured surfaces. The results revealed two distinct, protein-specific adsorption mechanisms on SiNP coatings. BSA adsorbed via strong protein-surface interactions that promoted conformational adaptation and localized shell-like coverage of individual nanoparticles-progressively occupying interparticle interstices but leaving the overall nanoparticle topography visible. In contrast, FG adsorption followed a concentration-dependent, two-stage process; proteins first adsorbing directly to the nanoparticle surface, and at higher coverages, associated via protein-protein interactions, producing a secondary, dynamic, and loosely bound outer layer. This FG protein layer reduced the root-mean-square roughness of the underlying surface from a peak of ∼13.2 to ∼7.8 nm while introducing pronounced molecular-level fluctuations at the interface, as inferred from tip-induced smearing in HS-AFM images. These findings demonstrate that the relevant biological interface is not a static substrate, but a dynamic, structurally defined protein layer, whose properties are dictated by both nanoscale surface topography and the characteristics of the adsorbing proteins.

Bacterial strains can be divided into pathogenic and nonpathogenic strains. Distinguishing between the characteristics of these two types will help us understand the mechanisms that bacteria use to cause infections. Thus, the differences in the adhesion to a model hydrophilic silicon nitride surface and in the conformational properties between pathogenic and nonpathogenic Listeria species were probed using atomic force microscopy (AFM). The AFM force-distance approach curves were fitted to two steric models, the steric model and the extended-steric model, which assume the presence of one or two brushes on the bacterial cell surface, respectively. Our results indicated that no significant differences were noticed in the mean adhesion forces measured for pathogenic and nonpathogenic strains using the silicon nitride model surface. However, a larger number of adhesion peaks was found in the AFM retraction curves of the pathogenic strains. Similarly, when the conformational properties, represented by the mean thickness and the mean grafting density of the biopolymer brush, were determined using the steric model, no significant differences were observed between the pathogenic and nonpathogenic strains. However, when the conformational properties, represented by the mean thickness and the mean grafting density of the two brush layers, were quantified using the extended-steric model, it was found that the pathogenic strains had a lower mean grafting density for the first long brush and a higher mean grafting density for the second short brush. Thus, our findings demonstrate that the extended-steric model provides a more detailed view of the conformational properties of Gram-positive Listeria strains and allows for the detection of existing differences.

We aimed to synthesize modified magnesium nanowire (Ti-NW-Mg) on the surface of titanium implants and to investigate its effects on bone binding by regulating macrophage polarization in vitro. The Ti-NW-Mg was synthesized from smooth titanium (CP-Ti) by hydrofluoric acid etching and high temperature alkalization, and then through the displacement reaction of magnesium sulfate solution with the titanium surface. The control groups were CP-Ti, sandblasted and etched with acid titanium (Ti-SLA), and only for micro/nano-modified titanium surfaces (Ti-NW). The physicochemical properties of the Ti-NW-Mg surface were examined. The biological effects of materials on RAW264.7 cells were compared, and the effects on osteogenesis by mediating RAW264.7 polarization were discussed. We observed the effect of the materials on osteogenesis through immunohistochemistry. In this experiment, the Ti-NW-Mg surface was interwoven into a nanotopological network, which released a specific concentration of magnesium ions and had good hydrophilicity. Compared to CP-Ti, Ti-SLA, and Ti-NW, Ti-NW-Mg reduced the proliferation of macrophages on the surface, inhibited inflammation, regulated macrophage polarization, and promoted bone formation. Ti-NW-Mg reduced the proliferation and adhesion of macrophages and decreased the release of inflammatory factors from macrophages. These results provide an essential experimental basis for the effect of Ti-NW-Mg on improving implant osteogenesis and increasing the implant success rate.

Vapor-deposited polymer films offer a solvent-free, scalable route to engineer optically functional biointerfaces with tunable geometry. Recently developed technologies, such as condensed droplet polymerization (CDP), enable the direct fabrication of polymer dome arrays (PDAs) with precise control over size, curvature, and array density, as key parameters for high-resolution imaging and cellular compatibility. This perspective highlights the unique advantages of CDP-based microlenses as solid immersion lenses for live-cell imaging, pointing to their potential integration into tissue scaffolds, point-of-care diagnostics, and drug delivery platforms. We further discuss how polymeric material selection could enable refractive index tuning, mechanical adaptability, and biocompatibility for diverse biological applications. These capabilities position CDP-fabricated microlenses as a multifunctional platform for high-resolution imaging and for exploring how precisely engineered surface curvatures influence curvature-mediated signaling, mechano-transduction, and intracellular communication.

The efficiency of enzymatic proteolysis is often attributed to the properties of the enzyme itself, with the substrate typically viewed as a passive participant. In this study, we demonstrate that the conformational state of the substrate critically influences proteolytic efficiency. Using human serum albumin (HSA) as a model substrate, papain as the enzyme, and urea as a controlled denaturing agent, we systematically investigated how substrate conformation might affect proteolysis. While papain maintains its structural and functional integrity across varying urea concentrations, HSA transitions through well-defined conformational states (native, compact intermediate, and unfolded), allowing us an opportunity to isolate the effects of the substrate structure. Utilizing site-specific fluorescent labeling and single-molecule fluorescence correlation spectroscopy, we monitor the progression of proteolysis. Our results show that digestion slows at 3M urea, where HSA adopts a compact form, and accelerates at 6M, where HSA takes on an unfolded state, compared to native HSA. These results reveal that substrate folding critically influences the digestion kinetics, probably by controlling protease accessibility and underscoring its importance in mechanistic enzymology and proteomics workflows.

Plasma-enhanced chemical vapor deposition is a versatile technology to control interactions at the biomaterial/biological environment interface. Plasma copolymerization is a related strategy that utilizes a mixed feedgas of two or more plasma precursors, whereby conformal coating surface properties can be controlled by simply varying the feedgas composition. This study reports a previously unexplored combination of plasma precursors-pentane and acrylic acid-to deposit coatings with tunable chemistry and wettability on silk fibroin constructs. Five pentane/acrylic acid feedgas compositions were utilized, ranging from 100%, 75%, 50%, 25%, to 0% pentane by pressure. Plasma-deposited coating properties were evaluated through water contact angle goniometry and x-ray photoelectron spectroscopy. Coating static water contact angle values were tunable between >90° and <55° depending on the feedgas composition. Plasma diagnostics and density functional theory were used to evaluate plasma precursor fragmentation. This library of plasma-modified silk-based materials can be used to design biomaterial surfaces that are "just right" for the intended biomedical setting.