Biomimetic theranostic nanoparticles for effective anticancer therapy and MRI imaging

Cancer remains a leading cause of mortality worldwide, necessitating the development of innovative therapeutic approaches. Nanoparticle-based drug delivery systems have garnered significant interest due to their multifunctionality, offering the potential to enhance cancer treatment efficacy and improve patient tolerability. Membrane-coated drug delivery systems hold great potential for enhancing the therapeutic outcome of nanoparticle-based anticancer therapies. In this study, we report the synthesis of multifunctional iron-functionalized mesoporous polydopamine nanoparticles (MPDAFe NPs). These nanoformulations demonstrate substantial potential for combining efficient drug delivery and magnetic resonance imaging (MRI) and showcase the advantages of biomimetic coating with tumor cell-derived membranes. This coating confers prolonged circulation and improved the targeting capabilities of the nanoparticles. Furthermore, comprehensive biosafety evaluations reveal negligible toxicity to normal cells, while the combined chemo- and phototherapy exhibited significant cytotoxicity towards cancer cells. Additionally, the photothermal effect evaluation highlights the enhanced cytotoxicity achieved through laser irradiation, showcasing the synergistic effects of the nanomaterials and photothermal therapy. Importantly, our chemotherapeutic effect evaluation demonstrates the superior efficacy of doxorubicin-loaded MPDAFe@Mem NPs (cancer cell membrane-coated MPDAFe NPs) in inhibiting cancer cell viability and proliferation, surpassing the potency of free doxorubicin. This study comprehensively investigates theranostic, membrane-coated drug delivery systems, underlining their potential to increase the efficacy of cancer treatment strategies. The multifunctional nature of the iron-functionalized polydopamine nanoparticles allows for efficient drug delivery and imaging capabilities, while the biomimetic coating enhances their biocompatibility and targeting ability. These findings contribute valuable insights towards the development of advanced nanomedicine for improved cancer therapeutics.

Micro/nano-patterns for enhancing differentiation of human neural stem cells and fabrication of nerve conduits via soft lithography and 3D printing

Topographical cues on materials can manipulate cellular fate, particularly for neural cells that respond well to such cues. Utilizing biomaterial surfaces with topographical features can effectively influence neuronal differentiation and promote neurite outgrowth. This is crucial for improving the regeneration of damaged neural tissue after injury. Here, we utilized groove patterns to create neural conduits that promote neural differentiation and axonal growth. We investigated the differentiation of human neural stem cells (NSCs) on silicon dioxide groove patterns with varying height-to-width/spacing ratios. We hypothesize that NSCs can sense the microgrooves with nanoscale depth on different aspect ratio substrates and exhibit different morphologies and differentiation fate. A comprehensive approach was employed, analyzing cell morphology, neurite length, and cell-specific markers. These aspects provided insights into the behavior of the investigated NSCs and their response to the topographical cues. Three groove-pattern models were designed with varying height-to-width/spacing ratios of 80, 42, and 30 for groove pattern widths of 1 μm, 5 μm, and 10 μm and nanoheights of 80 nm, 210 nm, and 280 nm. Smaller groove patterns led to longer neurites and more effective differentiation towards neurons, whereas larger patterns promoted multidimensional differentiation towards both neurons and glia. We transferred these cues onto patterned polycaprolactone (PCL) and PCL-graphene oxide (PCL-GO) composite 'stamps' using simple soft lithography and reproducible extrusion 3D printing methods. The patterned scaffolds elicited a response from NSCs comparable to that of silicon dioxide groove patterns. The smallest pattern stimulated the highest neurite outgrowth, while the middle-sized grooves of PCL-GO induced effective synaptogenesis. We demonstrated the potential for such structures to be wrapped into tubes and used as grafts for peripheral nerve regeneration. Grooved PCL and PCL-GO conduits could be a promising alternative to nerve grafting.

Hybrid Molecular Magnets with Lanthanide- and Countercation-Mediated Interfacial Electron Transfer between Phthalocyanine and Polyoxovanadate

A series of {V₁₂}-nuclearity polyoxovanadate cages covalently functionalized with one or sandwiched by two phthalocyaninato (Pc) lanthanide (Ln) moieties via V-O-Ln bonds were prepared and fully characterized for paramagnetic Ln = Sm^III-Er^III and diamagnetic Ln = Lu^III, including Y^III. The LnPc-functionalized {V₁₂O₃₂} cages with fully oxidized vanadium centers in the ground state were isolated as (nBu₄N)₃[HV₁₂O₃₂Cl(LnPc)] and (nBu₄N)₂[HV₁₂O₃₂Cl(LnPc)₂] compounds. As corroborated by a combined experimental (EPR, DC and AC SQUID, laser photolysis transient absorption spectroscopy, and electrochemistry) and computational (DFT, MD, and model Hamiltonian approach) methods, the compounds feature intra- and intermolecular electron transfer that is responsible for a partial reduction at V(3d) centers from V^V to V^IV in the solid state and at high sample concentrations. The effects are generally Ln dependent and are clearly demonstrated for the (nBu₄N)₃[HV₁₂O₃₂Cl(LnPc)] representative with Ln = Lu^III or Dy^III. Intramolecular charge transfer takes place for Ln = Lu^III and occurs from a Pc ligand via the Ln center to the {V₁₂O₃₂} core of the same molecule, whereas for Ln = Dy^III, only intermolecular charge transfer is allowed, which is realized from Pc in one molecule to the {V₁₂O₃₂} core of another molecule usually via the nBu₄N⁺ countercation. For all Ln but Dy^III, two of these phenomena may be present in different proportions. Besides, it is demonstrated that (nBu₄N)₃[HV₁₂O₃₂Cl(DyPc)] is a field-induced single molecule magnet with a maximal relaxation time of the order 10^-3 s. The obtained results open up the way to further exploration and fine-tuning of these three modular molecular nanocomposites regarding tailoring and control of their Ln-dependent charge-separated states (induced by intramolecular transfer) and relaxation dynamics as well as of electron hopping between molecules. This should enable us to realize ultra-sensitive polyoxometalate powered quasi-superconductors, sensors, and data storage/processing materials for quantum technologies and neuromorphic computing.

Multifunctional ZnO:Gd@ZIF-8 hybrid nanocomposites with tunable luminescent-magnetic performance for potential bioapplication

Novel multifunctional ZnO:Gd@ZIF-8 hybrid inorganic-organic nanocomposites with tunable luminescent-magnetic performance were successfully fabricated using wet chemistry synthesis routes. Physico-chemical characterization including crystal structure, phase compositions, morphology, surface properties, as well as photoluminescent and magnetic characteristics was performed using powder X-ray diffraction (XRD), FT-IR analysis, transmission and scanning electron microscopies (TEM/SEM), N₂ adsorption/desorption, SQUID magnetometer, and photoluminescence spectroscopy. The biological studies of obtained materials, such as cytotoxicity profile and in vitro MRI imaging also investigated for potential use as contrast agents. Results showed that the doping with Gd³⁺ in a broad concentration range and the presence of ZIF-8 layer on ZnO affect the physico-chemical properties of the obtained composites. The obtained porous ZnO:Gd@ZIF-8 composites were highly crystalline with a large surface area. The XRD study indicated the formation of hexagonal wurtzite structure for ZnO and ZnO:Gd³⁺ (1-5 at.%). Luminescent studies showed, that ZnO is an ideal matrix for the incorporation of Gd³⁺ ions in a broad concentration range with efficient green luminescence. The PL intensity reached the maximum up to 5 at.% of Gd³⁺. The zeta potential values indicated the good stability of obtained nanoparticles. Proposed new materials with paramagnetic behavior and outstanding MR imaging capability could be used as potential contrast agents for magnetic resonance imaging.

NIR-Responsive TiO2 Biometasurfaces: Toward In Situ Photodynamic Antibacterial Therapy for Biomedical Implants

Implant-related microbial infection is a challenging clinical problem, and its treatment requires efficient eradication of the biofilm from the implant surface. Near-infrared (NIR)-responsive strategies are proposed as an emerging efficient antibacterial therapy. However, the utilization of photosensitizers or photocatalytic/photothermal nanomaterials in the available approach likely induces high potential risks of interfacial deterioration and biosafety compromise. Herein, a TiO₂ /TiO_{2- x} metasurface with potent NIR-responsive antibacterial activity is produced on a Ti alloy implant by a newly invented topochemical conversion-based alkaline-acid bidirectional hydrothermal method (aaBH). Electromagnetic simulations prove that NIR absorption and near-field distribution of the metasurface can be tuned by the dimension and arrangement of the nanostructural unit. Promising antibacterial efficacy is proved by both in vitro and in vivo tests, with low-power NIR irradiation for 10 min. Besides, the designed nanostructure in the metasurface itself also shows excellence in enhancing the adhesion-related gene expression of human gingival fibroblasts that are exposed to 10 min of NIR irradiation, proving the potent nanostructure-induced biological effects. This work provides a biosafe and upscalable metasurfacing approach with extraordinary capacity of manipulating light adsorption, photocatalysis, and biological properties.

Nanosurfacing Ti alloy by weak alkalinity-activated solid-state dewetting (AAD) and its biointerfacial enhancement effect

Nanoscale manipulation of material surfaces can create extraordinary properties, holding great potential for modulating the implant-bio interface for enhanced performance. In this study, a green, simple and biocompatible nanosurfacing approach based on weak alkalinity-activated solid-state dewetting (AAD) was for the first time developed to nano-manipulate the Ti6Al4V surface by atomic self-rearrangement. AAD treatment generated quasi-periodic titanium oxide nanopimples with high surface energy. The nanopimple-like nanostructures enhanced the osteogenic activity of osteoblasts, facilitated M2 polarization of macrophages, and modulated the cross-talk between osteoblasts and macrophages, which collectively led to significant strengthening of in vivo bone-implant interfacial bonding. In addition, the titanium oxide nanopimples strongly adhered to the Ti alloy, showing resistance to tribocorrosion damage. The results suggest strong nano-bio interfacial effects, which was not seen for the control Ti alloy processed through traditional thermal oxidation. Compared to other nanostructuring strategies, the AAD technique shows great potential to integrate high-performance, functionality, practicality and scalability for surface modification of medical implants.

Enhanced Ordering of Block Copolymer Thin Films upon Addition of Magnetic Nanoparticles

The influence of magnetite nanoparticles coated with poly(acrylic acid) (Fe₃O₄@PAA NPs) on the organization of block copolymer thin films via a self-assembly process was investigated. Polystyrene-b-poly(4-vinylpyridine) films were obtained by the dip-coating method and thoroughly examined by X-ray reflectivity, transmission electron microscopy, atomic force microscopy, and grazing incidence small-angle scattering. Magnetic properties of the films were probed via superconducting quantum interference device (SQUID) magnetometry. It was demonstrated that due to the hydrogen bonding between P4VP and PAA, the Fe₃O₄@PAA NPs segregate selectively inside P4VP domains, enhancing the microphase separation process. This in turn, together with employing carefully optimized dip-coating parameters, results in the formation of hybrid thin films with highly ordered nanostructures. The addition of Fe₃O₄@PAA nanoparticles does not change the average interdomain spacing in the film lateral nanostructure. Moreover, it was shown that the nanoparticles can easily be removed to obtain well-ordered nanoporous templates.

Tuning Properties of Partially Reduced Graphene Oxide Fibers upon Calcium Doping

The arrangement of two-dimensional graphene oxide sheets has been shown to influence physico-chemical properties of the final bulk structures. In particular, various graphene oxide microfibers remain of high interest in electronic applications due to their wire-like thin shapes and the ease of hydrothermal fabrication. In this research, we induced the internal ordering of graphene oxide flakes during typical hydrothermal fabrication via doping with Calcium ions (~6 wt.%) from the capillaries. The Ca2+ ions allowed for better graphene oxide flake connections formation during the hydrogelation and further modified the magnetic and electric properties of structures compared to previously studied aerogels. Moreover, we observed the unique pseudo-porous fiber structure and flakes connections perpendicular to the long fiber axis. Pulsed electron paramagnetic resonance (EPR) and conductivity measurements confirmed the denser flake ordering compared to previously studied aerogels. These studies ultimately suggest that doping graphene oxide with Ca2+ (or other) ions during hydrothermal methods could be used to better control the internal architecture and thus tune the properties of the formed structures.

Silver and ultrasmall iron oxides nanoparticles in hydrocolloids: effect of magnetic field and temperature on self-organization

Micro/nanostructures, which are assembled from various nanosized building blocks are of great scientific interests due to their combined features in the micro- and nanometer scale. This study for the first time demonstrates that ultrasmall superparamagnetic iron oxide nanoparticles can change the microstructure of their hydrocolloids under the action of external magnetic field. We aimed also at the establishment of the physiological temperature (39 °C) influence on the self-organization of silver and ultrasmall iron oxides nanoparticles (NPs) in hydrocolloids. Consequences of such induced changes were further investigated in terms of their potential effect on the biological activity in vitro. Physicochemical characterization included X-ray diffraction (XRD), optical microscopies (SEM, cryo-SEM, TEM, fluorescence), dynamic light scattering (DLS) techniques, energy dispersive (EDS), Fourier transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectroscopies, zeta-potential and magnetic measurements. The results showed that magnetic field affected the hydrocolloids microstructure uniformity, fluorescence properties and photodynamic activity. Likewise, increased temperature caused changes in NPs hydrodynamic size distribution and in hydrocolloids microstructure. Magnetic field significantly improved photodynamic activity that was attributed to enhanced generation of reactive oxygen species due to reorganization of the microstructure.

Influence of silver content on rifampicin adsorptivity for magnetite/Ag/rifampicin nanoparticles

Magnetite nanoparticles (NPs) decorated with silver (magnetite/Ag) are intensively investigated due to their application in the biomedical field. We demonstrate that the increase of silver content on the surface of nanoparticles improves the adsorptivity of antibiotic rifampicin as well as antibacterial properties. The use of ginger extract allowed to improve the silver nucleation on the magnetite surface that resulted in an increase of silver content. Physicochemical and functional characterization of magnetite/Ag NPs was performed. Our results show that 5%-10% of silver content in magnetite/Ag NPs is already sufficient for antimicrobial properties against Streptococcus salivarius and Staphylococcus aureus. The rifampicin molecules on the magnetite/Ag NPs surface made the spectrum of antimicrobial activity wider. Cytotoxicity evaluation of the magnetite/Ag/rifampicin NPs showed no harmful action towards normal human fibroblasts, whereas the effect on human embryonic kidney cell viability was time and dose dependent.

The effect of Cu doping on the mechanical and optical properties of zinc oxide nanowires synthesized by hydrothermal route

Zinc oxide (ZnO) is a wide-bandgap semiconductor material with applications in a variety of fields such as electronics, optoelectronic and solar cells. However, much of these applications demand a reproducible, reliable and controllable synthesis method that takes special care of their functional properties. In this work ZnO and Cu-doped ZnO nanowires are obtained by an optimized hydrothermal method, following the promising results which ZnO nanostructures have shown in the past few years. The morphology of as-prepared and copper-doped ZnO nanostructures is investigated by means of scanning electron microscopy and high resolution transmission electron microscopy. X-ray diffraction is used to study the impact of doping on the crystalline structure of the wires. Furthermore, the mechanical properties (nanoindentation) and the functional properties (absorption and photoluminescence measurements) of ZnO nanostructures are examined in order to assess their applicability in photovoltaics, piezoelectric and hybrids nanodevices. This work shows a strong correlation between growing conditions, morphology, doping and mechanical as well as optical properties of ZnO nanowires.

Enhancement of optical and mechanical properties of Si nanopillars by ALD TiO2 coating

The mechanical and optical properties of Si and TiO₂–Si nanopillars (NPl) were investigated.

Synthesis and characterization of magnetite/silver/antibiotic nanocomposites for targeted antimicrobial therapy

The article is devoted to preparation and characterization of magnetite/silver/antibiotic nanocomposites for targeted antimicrobial therapy. Magnetite nanopowder was produced by thermochemical technique; silver was deposited on the magnetite nanoparticles in the form of silver clusters. Magnetite/silver nanocomposite was investigated by XRD, SEM, TEM, AFM, XPS, EDX techniques. Adsorptivity of magnetite/silver nanocomposite towards seven antibiotics from five different groups was investigated. It was shown that rifampicin, doxycycline, ceftriaxone, cefotaxime and doxycycline may be attached by physical adsorption to magnetite/silver nanocomposite. Electrostatic surfaces of antibiotics were modeled and possible mechanism of antibiotic attachment is considered in this article. Raman spectra of magnetite, magnetite/silver and magnetite/silver/antibiotic were collected. It was found that it is difficult to detect the bands related to antibiotics in the magnetite/silver/antibiotic nanocomposite spectra due to their overlap by the broad carbon bands of magnetite nanopowder. Magnetic measurements revealed that magnetic saturation of the magnetite/silver/antibiotic nanocomposites decreased on 6-19 % in comparison with initial magnetite nanopowder. Pilot study of antimicrobial properties of the magnetite/silver/antibiotic nanocomposites were performed towards Bacillus pumilus.

Tailoring mechanical properties and electrical conductivity of flexible niobium carbide nanocomposite thin films

This work shows the potential of hard, elastic and electrically conductive nanocomposite NbC films for nano- and micro- electronics applications.