Potential Use In Biomedical Applications Research Articles

Molecular dynamics simulations suggest the potential toxicity of fluorinated graphene to HP35 protein via unfolding the α-helix structure

Fluorinated graphene, a two-dimensional nanomaterial composed of three atomic layers, a central carbon layer sandwiched between two layers of fluorine atoms, has attracted considerable attention across various fields, particularly for its potential use in biomedical applications. Nonetheless, scant effort has been devoted to assessing the potential toxicological implications of this nanomaterial. In this study, we scrutinize the potential impact of fluorinated graphene on a protein model, HP35 by utilizing extensive molecular dynamics (MD) simulation methods. Our MD results elucidate that upon adsorption to the nanomaterial, HP35 undergoes a denaturation process initiated by the unraveling of the second helix of the protein and the loss of the proteins hydrophobic core. In detail, substantial alterations in various structural features of HP35 ensue, including alterations in hydrogen bonding, Q value, and RMSD. Subsequent analyses underscore that hydrophobic and van der Waals interactions (predominant), alongside electrostatic energy (subordinate), exert influence over the adsorption of HP35 on the fluorinated graphene surface. Mechanistic scrutiny attests that the unrestrained lateral mobility of HP35 on the fluorinated graphene nanomaterial primarily causes the exposure of HP35's hydrophobic core, resulting in the eventual structural denaturation of HP35. A trend in the features of 2D nanostructures is proposed that may facilitate the denaturation process. Our findings not only substantiate the potential toxicity of fluorinated graphene but also unveil the underlying molecular mechanism, which thereby holds significance for the prospective utilization of such nanomaterials in the field of biomedicine.

Bioactive Properties of Venoms Isolated from Whiptail Stingrays and the Search for Molecular Mechanisms and Targets.

The venom-containing barb attached to their 'whip-like' tail provides stingrays a defensive mechanism for evading predators such as sharks. From human encounters, dermal stingray envenomation is characterized by intense pain often followed by tissue necrosis occurring over several days to weeks. The bioactive components in stingray venoms (SRVs) and their molecular targets and mechanisms that mediate these complex responses are not well understood. Given the utility of venom-derived proteins from other venomous species for biomedical and pharmaceutical applications, we set out to characterize the bioactivity of SRV extracts from three local species that belong to the Dasyatoidea 'whiptail' superfamily. Multiple cell-based assays were used to quantify and compare the in vitro effects of these SRVs on different cell lines. All three SRVs demonstrated concentration-dependent growth-inhibitory effects on three different human cell lines tested. In contrast, a mouse fibrosarcoma cell line was markedly resistant to all three SRVs, indicating the molecular target(s) for mediating the SRV effects are not expressed on these cells. The multifunctional SRV responses were characterized by an acute disruption of cell adhesion leading to apoptosis. These findings aim to guide future investigations of individual SRV proteins and their molecular targets for potential use in biomedical applications.

Facile Synthesis of Novel Ti2C Nano Bipyramids for Photothermal and Photodynamic Therapy of Breast Cancer.

Photo-responsive synergetic therapeutics achieved significant attraction in cancer theranostic due to the versatile characteristics of nanomaterials. There have been substantial efforts in developing the simplest nano-design with exceptional synergistic properties and multifunctionalities. In this work, biocompatible Ti2C MXene nano bipyramids (MNBPs) were synthesized by hydrothermal method with dual functionalities of photothermal and photodynamic therapies. The MNBPs shape was obtained from two-dimensional (2D) Ti2C nanosheets by controlling the temperature of the reaction mixture. The structure of these Ti2C MNBPs was characterized by a high-resolution transmission electron microscope, scanning electron microscope, atomic force microscope, X-ray photoelectron spectroscopy, and X-ray diffraction. The Ti2C NBPs have shown exceptional photothermal properties with increased temperature to 72.3 °C under 808 nm laser irradiation. The designed nano bipyramids demonstrated excellent cellular uptake and biocompatibility. The Ti2C NBP has established a remarkable photothermal therapy (PTT) effect against 4T1 breast cancer cells. Moreover, Ti2C NBPs showed a profound response to UV light (6 mW/cm2) and produced reactive oxygen species, making them useful for photodynamic therapy (PDT). These in-vitro studies pave a new path to tune the properties of photo-responsive MXene nanosheets, indicating a potential use in biomedical applications.

Biodegradable Conductive Layers Based on a Biopolymer Polyhydroxybutyrate/Polyhydroxyvalerate and Graphene Nanoplatelets Deposited by Spray-Coating Technique

In light of the growing concern for environmental protection and the alarming amount of waste produced due to hygiene regulations, this study suggests a biodegradable and eco-friendly solution that could make a significant contribution to the preservation of our planet. The developed solution was based on a polyhydroxybutyrate/polyhydroxyvalerate biopolymer, which has been tested regarding its physicochemical parameters and possible use in printed electrically conductive structures. Graphene nanoplatelets have been used as the conductive functional phase, due to literature reports of their potential use in biomedical applications and due to the potential of providing cytocompatibility in electrical structures by carbon nanomaterials. Prepared composites have been spray-coated onto PET film and paper substrates and then subjected to electrical, adhesion and optical measurements. In order to establish the conductivity of the developed composite, its resistance, layer thickness and surface topography were measured. Optical parameters have been specified using scanning electron microscopy (SEM) imaging and spectrophotometry. The conducted research opens a wide path for the use of the polyhydroxybutyrate/polyhydroxyvalerate biopolymer with graphene nanoplatelets in biomedical applications, ensuring good conductivity, biocompatibility and stability.

Catalytically Propelled Micro‐ and Nanoswimmers

The last decade has seen a surge of interest in the field of catalytically propelled micro‐ and nanoswimmers for their potential use in biomedical applications, such as biosensing, biopsy, targeted drug delivery, and on‐the‐fly chemistry. However, to fully utilize these devices, precise control over their motion is essential. Therefore, it is important to thoroughly understand their locomotion mechanisms. Herein, the currently accepted mechanisms for propulsion are discussed, which are self‐electrophoresis, self‐diffusiophoresis, and bubble recoil. Additionally, the concept of using multilocomotive mechanisms as a solution to achieve fully autonomous navigation is explored. Moreover, recent advances in the design of these devices are explored.

Magnetic core/shell structures: A case study on the synthesis and phototoxicity/cytotoxicity tests of multilayer graphene encapsulated Fe/Fe3C nanoparticles

This study reports on a novel and optimized synthesis procedure of multilayer graphene (MLG) encapsulated Fe/Fe3C nanoparticles using a combined method of spray drying, chemical vapor deposition (CVD) and leaching from FeCl3.6 H2O based precursor, in addition to phototoxicity/cytotoxicity tests for their potential use in biomedical applications. CVD studies were employed at various temperature/time and gas flow rate values. Based on the X-ray diffractometry (XRD), Raman spectroscopy, vibrating sample magnetometry (VSM), transmission electron microscopy/energy-dispersive spectroscopy (TEM/EDS) and differential thermal analysis/thermogravimetry (DTA/TG), CVD parameters of 900 °C, 60 min, 50 mbar and CH4/H2:1/1 were determined as optimum conditions. MLG encapsulated (d-spacing: 0.34 nm) nanoparticles consisting BCC Fe, FCC (Fe, C) and orthorhombic Fe3C phases were obtained with average core diameter of ∼45 nm and average shell thickness of ∼6 nm (8–50 layers). MLG encapsulated Fe/Fe3C nanoparticles were achieved with soft ferromagnetic (Ms: ∼64 emu/g; Hc: ∼276 Oe) property. MLG coated Fe/Fe3C nanoparticles were suspended in an aqueous media using poly/acrylic acid as a post-synthetic treatment. They were found cytocompatible even at 200 µg/mL and 75 µg/mL after 24 and 48 h exposure, respectively. Dose dependent cytotoxicity was studied on both MCF7 and HeLa cells after 72 h incubation. Light-to-heat conversion efficiency of these nanoparticles at 795 nm irradiation in water was calculated as 37.60 %. After laser irradiation, with an increased concentration of nanoparticles (75–200 µg/mL), more than 80 % cell death was observed on both MCF7 and HeLa cells lines via late apoptotic cell death as a result of photothermal effect.

Synergistic Antibiofilm Effects of Exopolymers Produced by the Marine, Thermotolerant Bacillus licheniformis B3-15 and Their Potential Medical Applications

The exopolysaccharide (EPS B3-15) and biosurfactant (BS B3-15), produced by the marine Bacillus licheniformis B3-15, were recently reported to possess different antibiofilm activities, with the EPS being more active in preventing the adhesion of Pseudomonas aeruginosa and Staphylococcus aureus and the BS in destroying their preformed biofilms on different surfaces. In this study, the synergistic effects of the two exopolymers on the bacterial adhesion and biofilm disruption of P. aeruginosa and S. aureus were evaluated on polystyrene, a medical polyvinyl chloride (PVC) device, and contact lenses (CLs) in order to address their potential use in biomedical applications. To this purpose, EPS B3-15 and BS B3-15 were equally combined (1:1 w/w), and the mixture (BPS B3-15) was added at different concentrations (from 50 to 300 µg mL−1) and at different times of bacterial development. Compared to each polymer, the BPS B3-15 (300 µg mL−1) more efficiently reduced the adhesion of P. aeruginosa and S. aureus on polystyrene (65 and 58%, respectively), PVC devices (62 and 42%, respectively), and CLs (39 and 35%, respectively), also in combination with a CLs care solution (88 and 39%, respectively). Furthermore, BPS B3-15 was able to disrupt mature biofilms, acting more effectively against S. aureus (72%) than P. aeruginosa (6%). The combination of exopolymers at low concentrations exhibited synergistic effects to prevent and eradicate biofilms.

Antibacterial Activity of PVA Hydrogels Embedding Oxide Nanostructures Sensitized by Noble Metals and Ruthenium Dye.

Nanostructured oxides (SiO2, TiO2) were synthesized using the sol-gel method and modified with noble metal nanoparticles (Pt, Au) and ruthenium dye to enhance light harvesting and promote the photogeneration of reactive oxygen species, namely singlet oxygen (1O2) and hydroxyl radical (•OH). The resulting nanostructures were embedded in a transparent polyvinyl alcohol (PVA) hydrogel. Morphological and structural characterization of the bare and modified oxides was performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), UV-Vis spectroscopy, and X-ray photoelectron spectroscopy (XPS). Additionally, electrokinetic potential measurements were conducted. Crystallinity data and elemental analysis of the investigated systems were obtained through X-ray diffraction and X-ray fluorescence analyses, while the chemical state of the elements was determined using XPS. The engineered materials, both as simple powders and embedded in the hydrogel, were evaluated for their ability to generate reactive oxygen species (ROS) under visible and simulated solar light irradiation to establish a correlation with their antibacterial activity against Staphylococcus aureus. The generation of singlet oxygen (1O2) by the samples under visible light exposure can be of significant importance for their potential use in biomedical applications.

Tannic-acid-mediated synthesis and characterization of magnetite-gold nanoplatforms for photothermal therapy.

Aim: The design of new hybrid nanoplatforms (HNPs) through the innovative and eco-friendly use of tannic acid (TA) for the synthesis and stabilization of the nanoplatforms. Materials & methods: The size, morphology, composition and magnetic and plasmonic properties of HNPs were investigated together with their ability to generate heat under laser irradiation and the hemotoxicity to explore their potential use for biomedical applications. Results & conclusion: The use of TA allowed the synthesis of the HNPs by adopting a simple and green method. The HNPs preserved the peculiar properties of both magnetic and plasmonic nanoparticles and did not show any hemotoxic effect.

Properties of poly (lactic Acid)/ hydroxyapatite biocomposites for 3D printing feedstock material

In this study, biocomposites as feedstock material for 3D printing were produced by poly (lactic acid) (PLA) as a polymer matrix and Hydroxyapatite (HAP) as reinforcing filler for potential use in biomedical applications. Biocomposites filament from PLA and different HAP content varying from 1–10 wt% were prepared from extrusion and then injection moulding process. The impact of HAP loading on the properties of biocomposites was investigated for crystallinity, density, hardness, tensile, impact, flexural, melt flow index (MFI), thermal properties and biomineralization studies. The formation of PLA/HAP biocomposites was confirmed by fourier transform infrared spectroscopy (FTIR). The hydrophilicity of the biocomposites was studied by contact angle analysis. Dispersion of HAP into PLA matrix was confirmed by scanning electron microscopy (SEM) and optical microscopy. The HAP addition increased the density of the composites. From mechanical analysis PLA/HAP composites containing 1–5 wt% showed an increase in tensile modulus. The Shore D hardness of the composites increased with increase in wt% of HAP content. The maximum hardness was achieved for 10 wt% of HAP content i.e., 87 ± 0.1, which is about 6.1% more than neat PLA. The MFI increased with rise in HAP content that gives a positive opinion of reinforcing PLA composites without deteriorating the processability. The hydrophilicity of the biocomposites was slightly increased after the addition of HAP. From thermal analysis it was concluded that the thermal stability of the biocomposites increased when compared with neat PLA. From the Biomineralization studies formation of apatite layer on PLA composites was confirmed by SEM analysis.

Ficin-Cyclodextrin-Based Docking Nanoarchitectonics of Self-Propelled Nanomotors for Bacterial Biofilm Eradication.

Development of bioinspired nanomotors showing effective propulsion and cargo delivery capabilities has attracted much attention in the last few years due to their potential use in biomedical applications. However, implementation of this technology in realistic settings is still a barely explored field. Herein, we report the design and application of a multifunctional gated Janus platinum-mesoporous silica nanomotor constituted of a propelling element (platinum nanodendrites) and a drug-loaded nanocontainer (mesoporous silica nanoparticle) capped with ficin enzyme modified with β-cyclodextrins (β-CD). The engineered nanomotor is designed to effectively disrupt bacterial biofilms via H2O2-induced self-propelled motion, ficin hydrolysis of the extracellular polymeric matrix (EPS) of the biofilm, and controlled pH-triggered cargo (vancomycin) delivery. The effective synergic antimicrobial activity of the nanomotor is demonstrated in the elimination of Staphylococcus aureus biofilms. The nanomotor achieves 82% of EPS biomass disruption and a 96% reduction in cell viability, which contrasts with a remarkably lower reduction in biofilm elimination when the components of the nanomotors are used separately at the same concentrations. Such a large reduction in biofilm biomass in S. aureus has never been achieved previously by any conventional therapy. The strategy proposed suggests that engineered nanomotors have great potential for the elimination of biofilms.

Interactions between Layered Double Hydroxide Nanoparticles and Egg Yolk Lecithin Liposome Membranes.

The burgeoning need to study the applications of nanoparticles (NPs) in biomedical and pharmaceutical fields requires an understanding of their interactions with lipid membranes for further in vivo studies. In this paper, negatively charged egg yolk lecithin liposome (EYL) has been prepared and used as model lipid membranes. Positively charged Mg3Al-layered double hydroxides (LDHs) are viewed as models of clay particles. The ability of the LDH NPs, a two-dimensional nanostructure with an average diameter of 100 nm (LDHs-100) or 500 nm (LDHs-500) to cross the membranes, has been thoroughly investigated via (high-resolution) transmission electron microscopy (TEM), optical microscopy (OM), scanning electron microscopy (SEM), confocal fluorescence microscopy (CLSM), and dynamic light scattering (DLS). The liposomes with an average diameter of 1.5 μm were prepared by the thin-film rehydration method followed by an extrusion technique. A calcein leakage assay and steady-state fluorescence measurement displayed the variation of membrane integrity and polarity of the pyrene-located microenvironment during the interaction between EYL and calcein-interacted LDH NPs (CE-LDHs) or LDH NPs, respectively. These results imply that not only spherical particles but also even more sophisticated nanostructured materials are able to effectively cross the lipid bilayers, thereby engineering new compounds that may be encapsulated for safe and potential use in biomedical applications.

Green Biodegradable Polylactide-Based Polyurethane Triblock Copolymers Reinforced with Cellulose Nanowhiskers

A novel series of biodegradable polylactide-based triblock polyurethane (TBPU) copolymers covering a wide range of molecular weights and compositions were synthesized for potential use in biomedical applications. This new class of copolymers showed tailored mechanical properties, improved degradation rates, and enhanced cell attachment potential compared to polylactide homopolymer. Triblock copolymers, (TB) PL-PEG-PL, of different compositions were first synthesized from lactide and polyethylene glycol (PEG) via ring-opening polymerization in the presence of tin octoate as the catalyst. After which, polycaprolactone diol (PCL-diol) reacted with TB copolymers using 1,4-butane diisocyanate (BDI) as a nontoxic chain extender to form the final TBPUs. The final composition, molecular weight, thermal properties, hydrophilicity, and biodegradation rates of the obtained TB copolymers, and the corresponding TBPUs were characterized using 1H-NMR, GPC, FTIR, DSC, and SEM, and contact angle measurements. Results obtained from the lower molecular weight series of TBPUs demonstrated potential use in drug delivery and imaging contrast agents due to their high hydrophilicity and degradation rates. On the other hand, the higher molecular weight series of TBPUs exhibited improved hydrophilicity and degradation rates compared to PL-homopolymer. Moreover, they displayed improved tailored mechanical properties suitable for utilization as bone cement, or in regeneration medicinal applications of cartilage, trabecular, and cancellous bone implants. Furthermore, the polymer nanocomposites obtained by reinforcing the TBPU3 matrix with 7% (w/w) bacterial cellulose nanowhiskers (BCNW) displayed a ~16% increase in tensile strength, and 330% in % elongation compared with PL-homo polymer.

Three-dimensional printing of soft hydrogel electronics

Electronics based on hydrogels can have inherent similarities to biological tissue and are of potential use in biomedical applications. Ideally, such hydrogel electronics should offer customizable three-dimensional circuits, but making complex three-dimensional circuits encapsulated within a hydrogel matrix is challenging with existing materials and manufacturing methods. Here we report the three-dimensional printing of hydrogel electronics using a curable hydrogel-based supporting matrix and a stretchable silver–hydrogel ink. The supporting matrix has a yield stress fluid behaviour, so the shear force generated by a moving printer nozzle creates a temporary fluid-like state, allowing the accurate placement in the matrix of silver–hydrogel ink circuits and electronic components. After printing, the entire matrix and embedded circuitry can be cured at 60 °C to form soft (Young’s modulus of less than 5 kPa) and stretchable (elongation of around 18) monolithic hydrogel electronics, whereas the conductive ink exhibits a high conductivity of around 1.4 × 103 S cm−1. We use our three-dimensional printing approach to create strain sensors, inductors and biological electrodes.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV))/Bacterial Cellulose (BC) Biocomposites for Potential Use in Biomedical Applications.

The aim of this study was to obtain biocomposites consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), bacterial cellulose (BC) and α-tocopherol by a melt processing technique for potential use in biomedical applications. The melt processing and roughness of biocomposites were evaluated and compared to sample without BC. The degradation rate of PHBV/BC biocomposites was measured in phosphate buffer saline (PBS) by determining the mass variation and evidencing of thermal and structural changes by differential scanning calorimetry (DSC) and attenuated total reflectance-Fourier transformed infrared spectrometry (ATR-FTIR). The cell viability, cell morphology, cell cycle distribution and total collagen content were investigated on murine NCTC fibroblasts. Overall, the adding of BC to polyester matrix led to an adequate melt processing of biocomposites and increased surface roughness and cytocompatibility, allowing the cells to secrete the extracellular matrix (collagen) and stimulate cell proliferation. Results showed that the PHBV/BC biocomposites were favorable for long-term degradation and could be used for the design of medical devices with controlled degradability.

Chemical Profiling, Antiproliferative and Antimigratory Capacity of Haberlea rhodopensis Extracts in an In Vitro Platform of Various Human Cancer Cell Lines.

Haberlea rhodopensis is a Balkan endemic plant that belongs to the Gesneriaceae family, and is believed to have medicinal use and health-promoting properties. This study aimed to (i) prepare aqueous (HAE) and ethanolic (HEE) extracts from the leaves of H. rhodopensis from in vitro propagated plants, (ii) screen for their potential antiproliferative and antimigratory activities, and (iii) chemically characterize both HAE and HEE by identifying compounds which may contribute to their observed bioactivity thereby further supporting their potential use in biomedical applications. The antiproliferative activity of both extracts was assessed against six human cancer cell lines by employing the sulforhodamine-B (SRB) assay. HEE was found to be more potent in inhibiting cancer cell growth as compared to HAE. Therefore, HEE's antimigratory effects were further studied in hepatocellular carcinoma (HepG2) and non-small cell lung adenocarcinoma (A459) cell lines as they were among the most sensitive ones to its antiproliferative activity. HEE was found to exert significant antimigratory concentration-dependent effects in both cell lines assessed with the wound healing assay. Chemical characterization by UPLC-MS/MS analysis identified that HEE contains higher levels of flavonoids, phenolic compounds, pigments (chlorophyll-/-b, lycopene, and β-carotene), monoterpenoids, and condensed tannins compared to HAE, while HAE, contains higher levels of soluble protein and sugars. Furthermore, HEE demonstrated remarkable antioxidant activity evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH●), 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS●+) and ferric reducing/antioxidant power (FRAP) assays. We have obtained comprehensive results highlighting the potential of HEE as a source of bioactive compounds with anticancer properties. Future studies should aim at identifying the chemical constituents responsible for the bioactivities observed, and focus on investigating HEE's effects, in in vivo preclinical cancer models.

Permeation of flavonoid loaded human serum albumin nanoparticles across model membrane bilayers

The rapid growth in the applications of nanoparticles (NPs) in biomedical and pharmaceutical fields requires an understanding of the interactions with the lipid bilayer membrane for further in vivo studies. Zwitterionic 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), negatively charged 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS) and positively charged 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) have been used to prepare model lipid membranes and the ability of flavonoid loaded nanoparticles to cross the membranes investigated. The lipid vesicles have been prepared by a freeze-thaw method followed by an extrusion technique and characterised by dynamic light scattering (DLS) and high-resolution transmission electron microscopy (HRTEM). The synthesized model lipid membranes exhibited a bilayer spherical type of morphology with an average diameter of less than 150 nm. A calcein leakage assay and fluorescence anisotropy measurement indicated that the membranes are permeable to the flavonoid (fisetin/morin/epicatechin) loaded human serum albumin nanoparticles. This implies that drug/compound encapsulated nanoparticles are able to effectively cross the lipid bilayer thus permitting the design and development of new compounds that may be encapsulated for safe and potential use in biomedical applications.

Fabrication of polymer functionalized Mn2+-tannic acid coatings on magnetism-responsive nano-microspheres for Immobilized Penicillin G acylase

Firstly, Fe3O4 nanoparticles (Fe3O4 NPs) were synthesized by the inverse microemulsion method, and then, Mn2+ was doped in the process of coating tannin(TA) on the surface of Fe3O4 NPs to obtain Mn2+-Fe3O4@PTA NPs. The composite carrier containing Mn2+ could activate the catalytic activity of immobilized Penicillin G acylase (PGA). After the GMA was introduced into the carrier surface by ring-opening reaction, the above preparation carrier was modified by introducing RAFT reagent to obtain Mn2+-Fe3O4@PTA-GMA-g-RAFT NPs. Lastly, glycidyl methacrylate (GMA) and methyl methacrylate (MMA) were employed as the target monomer and the monomer for regulating the spacing between the targets, respectively. Herein, PGA was covalently immobilized on the surface of the magnetic microspheres by reaction of the amino groups of the PGA molecules with the epoxy groups of the magnetic polymer microspheres. Selections of immobilization conditions, including enzyme concentration, pH, temperature, and time of immobilization, were explored. The condition under which enzyme loading capacity (ELC), enzyme activity (EA), and enzyme activity recovery (EAR) of immobilized PGA were maximized as follows: enzyme concentration 2.5 vol%, pH = 8.0, time 20 h, and temperature 37 °C. Under the optimal immobilization conditions, ELC, EA, and EAR of immobilized PGA were 120 mg/g, 31,361 U/g, and 93.7%, respectively. Immobilized PGA remained 90.1% of initial activity and the carrier recovery was 97.8% after 14 successive cycles. These results indicated that the biocatalytic systems with potential use in biomedical application by the influence of polyhydroxy groups, target spacing, and Mn2+.

Metal-Phenolic Network-Functionalized Magnetic Nanoparticles for Enzyme Immobilization.

Metal-phenolic network (MPN) coating is an emerging class of surface functionalization method and has attracted ever-growing interest in areas of bioengineering and biotechnology. Although various applications for MPN coatings, including drug delivery, cytoprotection, and antimicrobial surfaces, have been studied in the form of films and capsules, their interaction with enzyme molecules and the subsequent influence of biocatalytic properties are poorly understood. Herein, MPN coatings composed of different types of metal ions (CuII, FeIII, ZnII, MnII, AuIV) coordinated with tannic acid (TA) were fabricated on Fe3O4 nanoparticles as a facile nanoplatform for immobilizing alcohol dehydrogenase (ADH). The results show that the different polarization capacities of metal ions (i.e., Lewis acids) could affect the hydrophilicity and hydrophobicity of the coordinated MPN coatings, while the enzyme immobilization rate, biocatalytic activity, and stability are in turn influenced by the surface properties of the MPN coatings. Among the different metal ions, the Fe3O4-TA-ZnII showed the highest enzyme immobilizing efficiency (91.53%) and catalytic activity (60.45 U/mg ADH). Besides, the enzyme re-usability and tolerance to extreme conditions were both enhanced after immobilization. These results highlight an advanced strategy for the interfacial construction of hybrid heterogeneous biocatalytic systems with potential use in biomedical applications.

Compositional Influence on the Morphology and Thermal Properties of Woven Non-Woven Mats of PLA/OLA/MgO Electrospun Fibers.

In the present work, a statistical study of the morphology and thermal behavior of poly(lactic acid) (PLA)/oligomer(lactic acid) (OLA)/magnesium oxide nanoparticles (MgO), electrospun fibers (efibers) has been carried out. The addition of both, OLA and MgO, is expected to modify the final properties of the electrospun PLA-based nanocomposites for their potential use in biomedical applications. Looking for the compositional optimization of these materials, a Box–Wilson design of experiment was used, taking as dependent variables the average fiber diameter as the representative of the fiber morphologies, as well as the glass transition temperature (Tg) and the degree of crystallinity (Xc) as their thermal response. The results show <r2> values of 73.76% (diameter), 88.59% (Tg) and 75.61% (Xc) for each polynomial fit, indicating a good correlation between both OLA and MgO, along with the morphological as well as the thermal behavior of the PLA-based efibers in the experimental space scanned.