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Biofunctionalization of selective laser melted porous titanium using silver and zinc nanoparticles to prevent infections by antibiotic-resistant bacteria
摘要： Antibiotic-resistant bacteria are frequently involved in implant-associated infections (IAIs), making the treatment of these infections even more challenging. Therefore, multifunctional implant surfaces that simultaneously possess antibacterial activity and induce osseointegration are highly desired in order to prevent IAIs. The incorporation of multiple inorganic antibacterial agents onto the implant surface may aid in generating synergistic antibacterial behavior against a wide microbial spectrum while reducing the occurrence of bacterial resistance. In this study, porous titanium implants synthesized by selective laser melting (SLM) were biofunctionalized with plasma electrolytic oxidation (PEO) using electrolytes based on Ca/P species as well as silver and zinc nanoparticles in ratios from 0 to 100% that were tightly embedded into the growing titanium oxide layer. After the surface bio-functionalization process, silver and zinc ions were released from the implant surfaces for at least 28 days resulting in antibacterial leaching activity against methicillin-resistant Staphylococcus aureus (MRSA). Furthermore, the biofunctionalized implants generated reactive oxygen species, thereby contributing to antibacterial contact-killing. While implant surfaces containing up to 75% silver and 25% zinc nanoparticles fully eradicated both adherent and planktonic bacteria in vitro as well as in an ex vivo experiment performed using murine femora, solely zinc-bearing surfaces did not. The minimum inhibitory and bactericidal concentrations determined for different combinations of both types of ions confirmed the presence of a strong synergistic antibacterial behavior, which could be exploited to reduce the amount of required silver ions by two orders of magnitude (i.e., 120 folds). At the same time, the zinc bearing surfaces enhanced the metabolic activity of pre-osteoblasts after 3, 7, and 11 days. Altogether, implant biofunctionalization by PEO with silver and zinc nanoparticles is a fruitful strategy for the synthesis of multifunctional surfaces on orthopedic implants and the prevention of IAIs caused by antibiotic-resistant bacteria.
关键词： Multifunctional biomaterials,silver and zinc nanoparticles,implant-associated infections,plasma electrolytic oxidation,additive manufacturing,MRSA
更新于2025-09-16 10:30:52
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Caries removal with Er:YAG laser followed by dentin biomodification with carbodiimide and chitosan: Wettability and surface morphology analysis
摘要： This study aimed to investigate dentin wettability and surface morphology after selective removal of carious lesion by erbium-doped yttrium aluminum garnet (Er: YAG) laser, followed by dentin biomodification with carbodiimide (EDC) and chitosan (CHI). Seventy-eight bovine dentin specimens were submitted to caries induction. Specimens were distributed according to methods of carious removal (n = 39): bur at low-speed (40,000 rpm) or Er:YAG laser (noncontact mode, 250 mJ/pulse and 4Hz). All specimens were etched with 35% phosphoric acid, and subdivided according to dentin biomodification (n = 13): Control (no biomodification), EDC or CHI. The contact angle (n = 10) between adhesive system (3M ESPE) and dentin surface was measured by a goniometer. Eighteen specimens (n = 3) were analyzed by scanning electron microscopy. Data were analyzed by two-way ANOVA and Tukey's test (α = .05). The method used to remove carious lesion did not influence the wettability of dentinal surface (p = .748). The angles produced on the remaining dentin after biomodification were influenced (p = .007). CHI promoted higher contact angles (p = .007) and EDC did not differ from the control group (p = .586). In the bur-treated group, most tubules were open, regardless of which biomodifier was used. Laser modified the organic matrix layer. CHI promoted partially closed tubules in some areas while EDC exposed dentinal tubules. Regardless of which method was used for selective removal of carious lesion, biomodification with EDC did not affect the dentin wettability, whereas CHI changed the wettability of remaining dentin. Both biomodifiers promoted a slight change on dentin morphology.
关键词： contact angle,biomaterials,SEM,caries-affected dentin,EDC
更新于2025-09-12 10:27:22
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Analysis of Plasmonic Gold Nanostar Arrays with the Optimum Sers Enhancement Factor on the Human Skin Tissue
摘要： We analyze the performance of the surface-enhanced Raman spectroscopy (SERS) substrate based on high-density gold nanostar nanoparticle (GNS) arrays assembled on the gold film and embedded in the human skin tissue as a surrounding medium. A self-assembled monolayer (SAM) of 3-aminopropyltriethoxy silane (APTES) is used for immobilizing GNSs on the Au film. The GNS–Au film and GNS–GNS coupling in the gap regions and also the GNSs interparticle coupling at their branches are observed, so the GNS arrays show more field enhancements and the sensitivity of the GNS sensor can be increased further. When the SERS substrate based on the GNS arrays is excited by a 785-nm laser line, a maximum enhancement factor (EF) of 109 is observed. It is demonstrated that the normalized EF depends on the geometry of the GNSs, the thickness of the Au film, and the separation distance between the cores of the GNSs.
关键词： thin films,spectroscopy,biomaterials,tissue diagnostics,nanostars,surface plasmons,plasmonics
更新于2025-09-12 10:27:22
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High Intensity Laser Induced Reverse Transfer: Solution for Enhancement of Biocompatibility of Transparent Biomaterials
摘要： Bioactive glass is used extensively in biomedical applications due to its quality and effectiveness in tissue regeneration. Bioactive glasses are able to interact with biological systems and can be used in humans to improve tissue regeneration without any side effects. Bioactive glass is a category of glasses that maintain good contact with body organs and remain biocompatible for a long time after implementation. They have the potential to form a hydroxyapatite surface as a biocompatible layer after immersion in body fluid. In this research, glass biocompatibility was modified using a deposition method called the high intensity laser induced reverse transfer (HILIRT) method and they were utilized as enhanced-biocompatibility bioactive glass (EBBG) with a correspondent nanofibrous titanium (NFTi) coating. HILIRT is a simple ultrafast laser method for improving implants for biomedical applications and provides a good thin film of NFTi on the glass substrate that is compatible with human tissue. The proposed method is a non-chemical method in which NFTi samples with different porosities and biocompatibilities are synthesized at various laser parameters such as power and frequency. Physical properties and cell compatibility and adhesion of these NFTi before and after immersion in simulated body fluid (SBF) were compared. The results indicate that increasing laser intensity and frequency leads to more NFTi fabrication on the glass with no toxicity and better cell interaction and adhesion.
关键词： biocompatibility,laser nanofabrication,nano fibrous biomaterials,transparent materials
更新于2025-09-12 10:27:22
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Advances in Contact Angle, Wettability and Adhesion || Laser Surface Engineering of Polymeric Materials for Enhanced Mesenchymal Stem Cell Adhesion and Growth
摘要： Owing to them being relatively inexpensive and easy to manipulate, polymers are becoming more widely used within the biomedical industry for several different applications. As an example, because of its high wear resistance, low moisture absorption and high chemical resistance, poly(ether ether ketone) is commonly used as a biomaterial in the healthcare and biomedical industries. However, poly(ether ether ketone) surface properties are not optimum for efficient or enhanced bio-functionality, leading it to have somewhat inferior wettability and adhesion characteristics. On account of this, many researchers are now looking to employ surface engineering techniques to improve and enhance the surface properties of poly(ether ether ketone), enhancing its biomimetic nature and improving the bio-adhesion properties. This chapter discusses the importance of Mesenchymal Stem Cells (MSCs), the biological applications of poly(ether ether ketone) and the application of lasers for surface engineering of poly(ether ether ketone) for modifying mesenchymal stem cell response. Through the application of CO2 laser surface engineering it has been shown that laser surface engineering can have a positive effect on the rate of human mesenchymal cell growth, highlighting the opportunities for the healthcare and biomedical industries to adopt such technique. In addition, discussion of including poly(ether ether ketone) and other polymer materials as bio-composite materials for future research is introduced for enhancing material properties.
关键词： surface modification,surface engineering,poly(ether ether ketone),Mesenchymal stem cells,polymeric biomaterials,bio-engineering,laser treatment
更新于2025-09-11 14:15:04
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Synchrotron infrared nanospectroscopy on a graphene chip
摘要： A recurring goal in biology and biomedicine research is to access the biochemistry of biological processes in liquids that represent the environmental conditions of living organisms. These demands are becoming even more specific as microscopy techniques are fast evolving to the era of single cells analysis. In the modality of chemical probes, synchrotron infrared spectroscopy (μ-FTIR) is a technique that is extremely sensitive to vibrational response of materials, however, the classical optical limits prevent the technique to access the biochemistry of specimens in the subcellular level. In addition, due to the intricate environmental requirements and strong infrared absorption of water, μ-FTIR of bioprocess in liquids remains highly challenging. In phase with those challenges, on-chip liquid cells emerge as a versatile alternative to control the water thickness while providing a biocompatible chemical environment for analytical analyzes. In this work we report the development of a liquid platform specially designed for nanoscale infrared analysis of biomaterials in wet environments. A key advantage of our designed platform is the use of graphene as the optical window that interfaces wet and dry environments in the liquid cell. By combining near-field optical microscopy and synchrotron infrared radiation, we measure nanoscale fingerprint IR absorbance of a variety of liquids often used in biological studies. Further, we demonstrate the feasibility of the platform for the chemical analysis of protein clusters immersed in water with a clear view of the proteins secondary structure signatures. The simplicity of the proposed platform combined to the high quality of our data make our findings a template for future microfluidic devices targeting dynamical nanoscale-resolved chemical analysis.
关键词： nanoscale chemical analysis,biomaterials,synchrotron infrared nanospectroscopy,graphene chip,liquid cell
更新于2025-09-11 14:15:04
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Biocompatibility Investigation of Hybrid Organometallic Polymers for Sub-Micron 3D Printing via Laser Two-Photon Polymerisation
摘要： Hybrid organometallic polymers are a class of functional materials which can be used to produce structures with sub-micron features via laser two-photon polymerisation. Previous studies demonstrated the relative biocompatibility of Al and Zr containing hybrid organometallic polymers in vitro. However, a deeper understanding of their effects on intracellular processes is needed if a tissue engineering strategy based on these materials is to be envisioned. Herein, primary rat myogenic cells were cultured on spin-coated Al and Zr containing polymer surfaces to investigate how each material affects the viability, adhesion strength, adhesion-associated protein expression, rate of cellular metabolism and collagen secretion. We found that the investigated surfaces supported cellular growth to full confluency. A subsequent MTT assay showed that glass and Zr surfaces led to higher rates of metabolism than did the Al surfaces. A viability assay revealed that all surfaces supported comparable levels of cell viability. Cellular adhesion strength assessment showed an insignificantly stronger relative adhesion after 4 h of culture than after 24 h. The largest amount of collagen was secreted by cells grown on the Al-containing surface. In conclusion, the materials were found to be biocompatible in vitro and have potential for bioengineering applications.
关键词： biomaterials,bioactive surfaces,laser two-photon polymerisation,tissue engineering,hybrid organometallic polymers
更新于2025-09-11 14:15:04
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Magnetic iron oxide nanoparticles/10-hydroxy camptothecin co-loaded nanogel for enhanced photothermal-chemo therapy
摘要： Iron oxide nanoparticle is a promising nano-biomaterial for treating iron deficiency, or as drug carriers and contrast agent as well as stimulator to elicit ROS generation. However, because of their intrinsic structure, therapeutic agents are hard to be loaded by them alone. Nanogel is a promising candidate for co-loading of iron oxide and therapeutic drug, due to its network structure and permeability. In this study, we use pre-prepared nanogel as surfactant to co-load hydrophobic magnetic nanoparticles (MNPs) and anti-cancer drug (10-hydroxy camptothecin, HCPT) to construct MNPs/HCPT-nanogel for cancer diagnosis and therapy. By in vitro and in vivo evaluation, we reveal that the obtained MNPs/HCPT-nanogel are stable in aqueous environment and can be served as drug delivery system to efficiently inhibit the tumor growth as well as MRI contrast agent for MR imaging. The introduction of MNPs elicits the generation of ROS with the presence of macrophage, which can further inhibit the growth of cancer cell. Furthermore, the introduction of extra-magnetic field can further enhance the enrichment of MNPs/HCPT-nanogel in the tumor site, which further improves the chemotherapeutic outcome. Besides, the obtained MNP/HCPT-nanogel can be used as nanocarrier for photothermal therapy for its absorption at NIR region. With the combination of PTT and chemotherapy, not only can the growth primary tumor be inhibited, but also the metastasis can be alleviated. It demonstrates that the MNP/HCPT-nanogel can be served as a promising candidate for cancer PTT/chemotherapy to inhibit tumor growth and alleviate metastasis.
关键词： Cancer diagnosis,Biomaterials,Photothermal therapy,Nanogel,Magnetic nanoparticle,10-Hydroxy camptothecin
更新于2025-09-10 09:29:36
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Toughness enhancers for bone scaffold materials based on biocompatible photopolymers
摘要： Providing access to the benefits of additive manufacturing technologies in tissue engineering, vinyl esters recently came into view as appropriate replacements for (meth)acrylates as precursors for photopolymers. Their low cytotoxicity and good biocompatibility as well as favorable degradation behavior are their main assets. Suffering from rather poor mechanical properties, particularly in terms of toughness, several improvements have been made over the last years. Especially, thiol–ene chemistry has been investigated to overcome those shortcomings. In this study, we focused on additional means to further improve the toughness of an already established biocompatible vinyl ester-thiol formulation, eligible for digital light processing-based stereolithography. All molecules were based on poly(ε-caprolactone) as building block and the formulations were tested regarding their reactivity and the resulting mechanical properties. They all performed well as toughness enhancer, ultimately doubling the impact resistance of the reference system.
关键词： rheology,polyesters,photopolymerization,biomaterials,monomers,FT-IR
更新于2025-09-10 09:29:36
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Biomaterials and Regenerative Medicine in Ophthalmology || An introduction to ophthalmic biomaterials and their role in tissue engineering and regenerative medicine
摘要： The ultimate goal of the research and development of materials (other than drugs) for applications in medicine, which we call biomaterials, has always been to emulate natural materials. Since the natural target for biomaterials, ie, our body’s tissues and organs, is exceedingly complex, it is not surprising that in many instances the laboratory-made materials cannot match in their performance the natural entities they are meant to augment or replace. This is obviously different from the development of materials for industrial applications, which usually perform better than their natural counterparts (if the latter exist), and also evolve relatively fast, unhindered by the biological constraints inherent to living systems. For too long, an acceptable end performance in the short term was the main requirement from a biomaterial, with little attention paid to changing its bulk and/or surface properties through the manipulation of composition and/or structure, in order to maximize the clinical outcome. Over the past six decades or so, however, the progress in bringing the properties and functionality of biomaterials close to those of their biological targets has been remarkable. While the previous statements are valid for the ophthalmic biomaterials too, their development has shown some particular features. The general developments in the field of biomaterials have customarily been gauged through the achievements in the branches of orthopaedic biomaterials and, to a lesser extent, biomaterials for cardiology or dentistry, while the progress of biomaterials for the eye has usually been ignored or seldom presented.
关键词： ophthalmic biomaterials,artificial cornea,poly(methyl methacrylate),contact lenses,hydrogels,cornea,regenerative medicine,tissue engineering
更新于2025-09-10 09:29:36