Antimicrobial Biomaterials Based on Physical and Physicochemical Action.

Developing effective antimicrobial biomaterials is a relevant and fast-growing field in advanced healthcare materials. Several well-known (e.g.

Effects of bone surface topography and chemistry on macrophage polarization.

Surface structure plays a crucial role in determining cell behavior on biomaterials, influencing cell adhesion, proliferation, differentiation, as well as immune cells and macrophage polarization. While grooves and ridges stimulate M2 polarization and pits and bumps promote M1 polarization, these structures do not accurately mimic the real bone surface. Consequently, the impact of mimicking bone surface topography on macrophage polarization remains unknown.

The Effect of Stereocomplexation and Crystallinity on the Degradation of Polylactide Nanoparticles.

Polymeric nanoparticles (PNPs) are frequently researched and used in drug delivery. The degradation of PNPs is highly dependent on various properties, such as polymer chemical structure, size, crystallinity, and melting temperature. Hence, a precise understanding of PNP degradation behavior is essential for optimizing the system.

The Controversial Effect of Antibiotics on Methicillin-Sensitive : A Comparative In Vitro Study.

Methicillin-sensitive () (MSSA) bacteremia remains a global challenge, despite the availability of antibiotics. Primary treatments include β-lactam agents such as cefazolin and flucloxacillin. Ongoing discussions have focused on the potential synergistic effects of combining these agents with rifampicin or fosfomycin to combat infections associated with biofilm formation.

How Crystallographic Orientation-Induced Fibrinogen Conformation Affects Platelet Adhesion and Activation on TiO.

Control of protein adsorption is essential for successful integration of healthcare materials into the body. Human plasma fibrinogen (HPF), especially its conformation is a key upstream regulator for platelet behavior and thus pathological clot formation at the blood-biomaterial interface. A previous study by the authors revealed that the conformation of adsorbed HPF can be controlled by rutile surface crystallographic orientation.

Bone surface mimicked PDMS membranes stimulate osteoblasts and calcification of bone matrix.

Cellular microenvironments play a crucial role in cell behavior. In addition to the biochemical cues present in the microenvironments, biophysical and biomechanical properties on surfaces have an impact on cellular functionality and eventually cellular fate. Effects of surface topography on cell behavior are being studied extensively in the literature.

Antibacterial Designs for Implantable Medical Devices: Evolutions and Challenges.

The uses of implantable medical devices are safer and more common since sterilization methods and techniques were established a century ago; however, device-associated infections (DAIs) are still frequent and becoming a leading complication as the number of medical device implantations keeps increasing. This urges the world to develop instructive prevention and treatment strategies for DAIs, boosting the studies on the design of antibacterial surfaces. Every year, studies associated with DAIs yield thousands of publications, which here are categorized into four groups, i.

Fracture toughness of 3Y-TZP ceramic measured by the Chevron-Notch Beam method: A round-robin study.

Objective: This interlaboratory round robin test investigated the robustness of the Chevron-Notch Beam (CNB) test method and the effect of the processing and testing variations on the fracture toughness of a dental 3Y-TZP ceramic.

Methods: The round robin test was performed precisely following the procedures recommended in ISO 24370:2005 and applied on a commercial 3Y-TZP ceramic (product information). A total of 335 test specimens with dimensions 3×4 x 45 mm³ was equally distributed among 10 participating laboratories of varying experience in fracture toughness testing.

The antimicrobial effect of calcium-doped titanium is activated by fibrinogen adsorption.

Directly targeting bacterial cells is the present paradigm for designing antimicrobial biomaterial surfaces and minimizing device-associated infections (DAIs); however, such pathways may create problems in tissue integration because materials that are toxic to bacteria can also be harmful to mammalian cells. Herein, we report an unexpected antimicrobial effect of calcium-doped titanium, which itself has no apparent killing effect on the growth of pathogenic bacteria (, , ATCC 27853) while presenting strong inhibition efficiency on bacterial colonization after fibrinogen adsorption onto the material. Fine X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy analyses reported calcium-dependent shifts of the binding energy in nitrogen and oxygen involved groups and wavenumbers in the amide I and II bands of the adsorbent fibrinogen, demonstrating that locally delivered calcium can react with the carboxy-terminal regions of the Aα chains and influence their interaction with the N-termini of the Bβ chains in fibrinogen.

Rutile facet-dependent fibrinogen conformation: Why crystallographic orientation matters.

Previous studies implied that single crystalline rutile surfaces have the ability to guide the functionality of adsorbed blood plasma proteins. However, a clear relation between the rutile crystallographic orientation and conformation of adsorbed proteins is still missing. Here, we examine the adsorption characteristics of human plasma fibrinogen (HPF) on atomically flat single rutile crystals with (110), (100), (101) and (001) facets.

Self-assembled fibrinogen-fibronectin hybrid protein nanofibers with medium-sensitive stability.

Hybrid protein nanofibers (hPNFs) have been identified as promising nano building blocks for numerous applications in nanomedicine and tissue engineering. We have recently reported a nature-inspired, self-assembly route to create hPNFs from human plasma proteins, , albumin and hemoglobin. However, it is still unclear whether the same route can be applied to other plasma proteins and whether it is possible to control the composition of the resulting fibers.

Osteocytes Influence on Bone Matrix Integrity Affects Biomechanical Competence at Bone-Implant Interface of Bioactive-Coated Titanium Implants in Rat Tibiae.

Osseointegration is a prerequisite for the long-term success of implants. Titanium implants are preferred for their biocompatibility and mechanical properties. Nonetheless, the need for early and immediate loading requires enhancing these properties by adding bioactive coatings.

Drug delivery of 6-bromoindirubin-3'-glycerol-oxime ether employing poly(D,L-lactide-co-glycolide)-based nanoencapsulation techniques with sustainable solvents.

Background: Insufficient solubility and stability of bioactive small molecules as well as poor biocompatibility may cause low bioavailability and are common obstacles in drug development. One example of such problematic molecules is 6-bromoindirubin-3'-glycerol-oxime ether (6BIGOE), a hydrophobic indirubin derivative. 6BIGOE potently modulates the release of inflammatory cytokines and lipid mediators from isolated human monocytes through inhibition of glycogen synthase kinase-3 in a favorable fashion.

Effectiveness of Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) Compared to Fluoride Products in an In-Vitro Demineralization Model.

The goal of this study was to evaluate the effectiveness of the toothpaste Tooth Mousse compared to conventional fluoride-based versions in the prevention of enamel and dentin demineralization. Human enamel and dentin samples ( = 120 each) were exposed to artificial demineralization at pH 4.92.

Infections @ Trauma/Orthopedic Implants: Recent Advances on Materials, Methods, and Microbes-A Mini-Review.

Implants and materials are indispensable in trauma and orthopedic surgery. The continuous improvements of implant design have resulted in an optimized mechanical function that supports tissue healing and restoration of function. One of the still unsolved problems with using implants and materials is infection.

Distinct endocytosis and immune activation of poly(lactic-co-glycolic) acid nanoparticles prepared by single- and double-emulsion evaporation.

Poly(lactic-co-glycolic) acid (PLGA) nanoparticles can be prepared by emulsion-solvent-evaporation from o/w and w/o/w emulsions. To elaborate similarities and differences regarding mechanical, morphological and physicochemical properties, as well as endocytosis and dose-dependent immune responses by primary human leukocytes between nanoparticles prepared by these two methods. Fluorescently labeled as well as TLR agonist (R848)-loaded PLGA nanoparticles were prepared via both single- and double-emulsion solvent evaporation.

The Action-Networks of Nanosilver: Bridging the Gap between Material and Biology.

The emergence of nanosilver (silver in nanoscale shapes and their assemblies) benefits the landscape of modern healthcare; however, this brings about concerns over its safety issues associated with an ultrasmall size and high mobility. By reviewing previous reporting details about the synthesis and characterization of nanosilver and its biological responses, a gap between materials synthesis and their biomedical uses is characterized by the insufficient understanding of the interacting and interplaying nanoscale actions of silver. To improve reporting quality and advance clinical translations, it is suggested that researchers have a comprehensive recognition of the "Indications for use" before designing innovative nanosilver-based materials and an "Action-network" concept addressing the acting range and strength of those nanoscale actions is implemented.

Performance of Calcium Phosphate Cements in the Augmentation of Sheep Vertebrae-An Ex Vivo Study.

Oil-based calcium phosphate cement (Paste-CPC) shows not only prolonged shelf life and injection times, but also improved cohesion and reproducibility during application, while retaining the advantages of fast setting, mechanical strength, and biocompatibility. In addition, poly(L-lactide-co-glycolide) (PLGA) fiber reinforcement may decrease the risk for local extrusion. Bone defects (diameter 5 mm; depth 15 mm) generated ex vivo in lumbar (L) spines of female Merino sheep (2-4 years) were augmented using: (i) water-based CPC with 10% PLGA fiber reinforcement (L3); (ii) Paste-CPC (L4); or (iii) clinically established polymethylmethacrylate (PMMA) bone cement (L5).

Sustainable preparation of anti-inflammatory atorvastatin PLGA nanoparticles.

In the present study, the anti-inflammatory lipophilic drug atorvastatin was encapsulated in poly(D,L-lactide-co-glycolide) (PLGA) using a sustainable method in comparison to the standard emulsion-diffusion-evaporation technique. For the sustainable method the organic solvent ethyl acetate was fully replaced by 400 g/mol poly(ethylene glycol) (PEG 400). Both techniques led to the formation of nanoparticles with comparable sizes of about 170 to 247 nm depending on the polymer type, with monomodal size distribution and negative zeta potential.

Biopolymer surface modification of PLGA fibers enhances interfacial shear strength and supports immobilization of rhGDF-5 in fiber-reinforced brushite cement.

Incorporation of biodegradable poly(lactic-co-glycolic acid; PLGA) fibers into calcium phosphate cements (CPCs) has proven beneficial for their mechanical properties and the targeted delivery of bone morphogenetic proteins (BMPs). However, the deficiency of functional groups on the PLGA surface results in poor fiber-matrix interfacial strength (ISS), limiting the mechanical improvement, and insufficient surface charge to immobilize therapeutic amounts of BMPs. The present study therefore focused on the: i) functionalization of PLGA fibers using polyelectrolyte multilayers (PEMs) of biopolymers; ii) analysis of their impact on the mechanical properties of the CPC in multifilament fiber pull-out tests; and iii) testing of their applicability as carriers for BMPs using chemical-free adsorption of biotinylated recombinant human growth factor (rhGDF-5) and colorimetric assays.

Polystyrene Homopolymer Enhances Dispersion of MWCNTs Stabilized in Solution by a PS--P2VP Copolymer.

Block copolymers (BCPs) have previously been identified as powerful multiwalled carbon nanotube (MWCNT) dispersants in solution. However, relatively high costs and limited dispersibility hinder the use of BCPs in large-scale practical applications. Partial replacement of BCP with a low-cost homopolymer (HP) offers a promising approach to produce cost-effective MWNCT dispersions.

Nanotechnology in dentistry: Present and future perspectives on dental nanomaterials.

Objectives: The number of dental nanomaterials has increased significantly over the past years. A variety of commercial dental nanomaterials are available and researched. Nevertheless, how these nanomaterials work, what makes them special and whether they are superior to traditional dental materials is not always clear to dentists and researchers.

How Nanotopography-Induced Conformational Changes of Fibrinogen Affect Platelet Adhesion and Activation.

The conformational state of adsorbed human plasma fibrinogen (HPF) has been recognized as the determinant factor in platelet adhesion and thrombus formation on blood-contacting biomaterials. Studies have highlighted the ability to control the HPF conformation merely by tailoring surface nanotopographical features. However, a clear relationship between the conformational changes of adsorbed HPF and the degree of platelet adhesion and activation achieved with different surface nanotopographies is still unclear.

Quantifying the relationship between surfaces' nano-contact point density and adhesion force of Candida albicans.

It has been recently recognized that controlled surface structuring on the nanometer scale is a successful strategy to endow different materials with antimicrobial properties. Despite many studies on bacterial interactions with nanostructured surfaces, a quantitative link between surface topography and bacterial adhesion is still missing. To quantitatively link cell adhesion data with topographical surface parameters, we performed single-cell spectroscopy on chemically identical surfaces with controlled nano-contact point density achieved by immobilization of gold nanoparticles (AuNP) on gold thin films.

The old sheep: a convenient and suitable model for senile osteopenia.

Introduction: Existing osteoporosis models in sheep exhibit some disadvantages, e.g., challenging surgical procedures, serious ethical concerns, failure of reliable induction of substantial bone loss, or lack of comparability to the human condition.