Nature-Inspired Biomolecular Corona Based on Poly(caffeic acid) as a Low Potential and Time-Stable Glucose Biosensor.

Herein, we present a novel biosensor based on nature-inspired poly(caffeic acid) (PCA) grafted to magnetite (Fe3O4) nanoparticles with glucose oxidase (GOx) from Aspergillus niger via adsorption technique. The biomolecular corona was applied to the fabrication of a biosensor system with a screen-printed electrode (SPE). The obtained results indicated the operation of the system at a low potential (0.1 V). Then, amperometric measurements were performed to optimize conditions like various pH and temperatures. The SPE/Fe3O4@PCA-GOx biosensor presented a linear range from 0.05 mM to 25.0 mM, with a sensitivity of 1198.0 µA mM-1 cm-2 and a limit of detection of 5.23 µM, which was compared to other biosensors presented in the literature. The proposed system was selective towards various interferents (maltose, saccharose, fructose, L-cysteine, uric acid, dopamine and ascorbic acid) and shows high recovery in relation to tests on real samples, up to 10 months of work stability. Moreover, the Fe3O4@PCA-GOx biomolecular corona has been characterized using various techniques such as Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Bradford assay.

Glucose determination using amperometric non-enzymatic sensor based on electroactive poly(caffeic acid)@MWCNT decorated with CuO nanoparticles.

A novel non-enzymatic glucose sensor based on poly(caffeic acid)@multi-walled carbon nanotubes decorated with CuO nanoparticles (PCA@MWCNT-CuO) was developed. The described approach involves the complexation/accumulation of Cu(II) on PCA@MWCNT followed by electrochemical CuO deposition in an alkaline electrolyte. The morphology and surface characteristics of the nanomaterial were determined by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), Raman spectroscopy, and inductively coupled plasma mass spectrometry (ICP-MS). A hybrid-support sensor device was then developed to assess the glucose concentration in different solutions. The sensitivity of the electrode is 2412 µA mM-1 cm-2. The electrode exhibited a broad linear range of 2 µM to 9 mM and a low limit of detection (LOD) of 0.43 µM (relative standard deviation, RSD = 2.3%) at + 0.45 V vs Ag/AgCl. The excellent properties obtained for glucose detection were most likely due to the synergistic effect of the combination of individual components: poly(caffeic acid), MWCNTs, and CuO. Good accuracy and high precision were demonstrated for quantifying glucose concentrations in human serum and blood samples (the recovery ranged from 95.0 to 99.5%). The GC/PCA@MWCNT-CuO sensor represents a novel, simple, and low-cost approach to the fabrication of devices for amperometric sensing of glucose.

Portable glucose biosensor based on polynorepinephrine@magnetite nanomaterial integrated with a smartphone analyzer for point-of-care application.

This work describes a novel nanoplatform based on polynorepinephrine (PNE) grafted on magnetite nanoparticles (Fe3O4) with glucose oxidase (GOx) from Aspergillus niger (Fe3O4@PNE-GOx). The system was integrated with a smartphone analyzer as a potential point-of-care testing (POCT) biosensor for glucose measurement. Covering the magnetite surface with the biomimetic polymer polynorepinephrine significantly increased the effectiveness of enzyme immobilization which was 38.40 mg g-1, compared with 17.30 mg g-1 on the bare surface of magnetite. The Fe3O4@PNE-GOx nanoplatform was deposited on a screen-printed electrode (SPE) and then used with the world's smallest ready-to-go potentiostat and a smartphone in tandem for glucose measurement. This biosensor displayed abroad range of linearity (0.2-24 mM), a low detection limit (6.1 µM), and good sensitivity (97.34 µA mM-1 cm-2). Moreover, it exhibited a fast electrocatalytic response (8 s), and long-term stability (up to 20 weeks). It was used to detect glucose in real samples such as human serum, human blood, infusion fluid, and commercial glucose solutions. The results obtained indicate that the proposed biosensor may be an attractive system for point-of-care testing (POCT), or in various industries, using asmartphone and potentiostat in tandem.

Magnetite Nanoparticles and Spheres for Chemo- and Photothermal Therapy of Hepatocellular Carcinoma in vitro.

INTRODUCTION: We present a multimodal nanoplatforms for the treatment of hepatocellular carcinoma (HCC) in vitro. The nanoplatforms are based on polydopamine (PDA)-coated magnetite nanoparticles (NPs) and spheres (sMAG) with PAMAM dendrimers and functionalized with NHS-PEG-Mal (N-hydroxysuccinimide-polyethylene glycol-maleimide) linker, which allows their functionalization with a folic acid derivative. The nanomaterials bearing a folic acid-targeting moiety show high efficiency in killing cancer cells in the dual chemo- and photothermal therapy (CT-PTT) of the liver cancer cells in comparison to modalities performed separately. MATERIALS AND METHODS: All materials are characterized in detail with transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, zeta potential and magnetic measurements. Also, photothermal properties were determined under irradiation of nanoparticles with laser beam of 2 W/cm2. The nontoxicity of nanoparticles with doxorubicin and without was checked by WST and LIVE/DEAD assay. Those tests were also used to evaluate materials bearing folic acid and anticancer drug in combined chemo- and photothermal therapy of HCC. Further, the generation of reactive oxygen species profile was also evaluated using flow cytometry test. RESULTS: Both NPs and sMAG showed high photothermal properties. Nevertheless, the higher photothermal response was found for magnetic spheres. Materials of concentration above 10 µg/mL reveal that their activity was comparable to free doxorubicin. It is worth highlighting that a functionalized magnetic sphere with DOXO more strongly affected the HepG2 cells than smaller functionalized nanoparticles with DOXO in the performed chemotherapy. This can be attributed to the larger size of particles and a different method of drug distribution. In the further stage, both materials were assessed in combined chemo- and photothermal therapy (CT-PTT) which revealed that magnetic spheres were also more effective in this modality than smaller nanoparticles. CONCLUSION: Here, we present two types of nanomaterials (nanoparticles and spheres) based on polydopamine and PAMAM dendrimers g.5.0 functionalized with NHS-PEG-Mal linker terminated with folic acid for in vitro hepatocellular carcinoma treatment. The obtained materials can serve as efficient agents for dual chemo- and photothermal therapy of HCC. We also proved that PDA-coated magnetic spheres were more efficient in therapies based on near-infrared irradiation because determined cell viabilities for those materials are lower than for the same concentrations of nanomaterials based on small magnetic nanoparticles.

Bio-inspired magnetite/lignin/polydopamine-glucose oxidase biosensing nanoplatform. From synthesis, via sensing assays to comparison with others glucose testing techniques.

Glucose monitoring has become a crucial part of diabetes care, and is also of importance in the food industry. However, the measurements are subject to certain limitations and errors. These may result from many factors, including the strip manufacturing process, inappropriate storage, temperature, coding, aging, etc. Here, we discuss the measurement of glucose in real samples using techniques such as photometric assay, glucometers, and using a proposed biosensor. Biosensor platforms based on the multicomponent material magnetite/lignin/polydopamine-glucose oxidase with the addition of ferrocene and a dedicated carbon paste electrode (CPE/Fe3O4/Lig/PDA/GOx/Fc) were fabricated for glucose detection in real, commercially available glucose-based samples. To determine the morphological features of the materials, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), atomic force microscopy (AFM) and zeta potential measurements were carried out. Moreover, to determine the effectiveness of glucose oxidase immobilization the Bradford assays was applied. Analysis of glucose-based products was carried out based on photometric measurements using an AU480 Chemical Analyzer from Beckam Coulter, with the use of three glucometers (Wellion Calla light® WELL 900LB, CERA-CHEK 1Code®Model G400, iXell®Rev.04/10-PL), and with the use of our proposed CPE/Fe3O4/Lig/PDA/GOx/Fc biosensor. Tests on real samples demonstrated the repeatability of the results. The results showed that this biosensor has excellent potential for application in the determination of glucose in various commercial products.

Dendrimer based theranostic nanostructures for combined chemo- and photothermal therapy of liver cancer cells in vitro.

Here we report the synthesis of multifunctional nanocarriers based on PAMAM dendrimers generation (G) 4.0, 5.0 and 6.0 fixed to polydopamine (PDA) coated magnetite nanoparticles (Fe3O4). Synthesized nanoplatforms were characterized by transmission electron microscopy (TEM), the electrokinetic (zeta) potential, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and magnetic resonance imaging (MRI). Further, we show as a proof of concept that nanocarriers functionalized with G 5.0 could be successfully applied in combined chemo- and photothermal therapy (CT-PTT) of the liver cancer cells. The cooperative effect of the modalities mentioned above led to higher mortality of cancer cells when compared to their individual performance. Moreover, the performed in vitro studies revealed that the application of dual therapy triggered the desired cell death mechanism-apoptosis. Furthermore, performed tests using Magnetic Resonance Imaging (MRI) showed that our materials have competitive contrast properties. Overall, the functionality of dendrimers has been extended by merging them with magnetic nanoparticles resulting in multifunctional hybrid nanostructures that are promising smart drug delivery system for cancer therapy.

Biopolymers conjugated with magnetite as support materials for trypsin immobilization and protein digestion.

In the presented study synthesized magnetic nanoparticles were used as an inorganic precursor for the preparation of novel magnetite-lignin and magnetite-chitin hybrid supports for enzyme immobilization. Effective synthesis of the hybrids was confirmed by Fourier transform infrared spectroscopy and powder X-ray diffraction analysis. The materials exhibited good thermal stability and surface areas of 4.3 and 5.6 m2/g respectively. The magnetite-lignin + trypsin and magnetite-chitin + trypsin systems were found to have good storage stability and reusability. After 20 days they retained over 75% and 90% respectively of their initial activity, and after 10 consecutive biocatalytic cycles retained over 60% and 80% respectively of their initial activity. The kinetic parameters of the free and immobilized enzyme were also comprehensively examined and compared. The results of peptide digestion tests confirmed the high proteolytic activity of the produced trypsin-based magnetic biocatalytic systems.

Cyclodextrin-Based Magnetic Nanoparticles for Cancer Therapy.

Polydopamine (PDA)-coated magnetic nanoparticles functionalized with mono-6-thio-ß-cyclodextrin (SH-ßCD) were obtained and characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Nuclear and Magnetic Resonance Imaging (NMR and MRI), and doxorubicin (DOXO)-loading experiments. The liver cancer cellular internalization of DOXO-loaded nanoparticles was investigated by confocal imaging microscopy. Synthesized nanomaterials bearing a chemotherapeutic drug and a layer of polydopamine capable of absorbing near-infrared light show high performance in the combined chemo- and photothermal therapy (CT-PTT) of liver cancer due to the synergistic effect of both modalities as demonstrated in vitro. Moreover, our material exhibits improved T2 contrast properties, which have been verified using Carr-Purcell-Meiboom-Gill pulse sequence and MRI Spin-Echo imaging of the nanoparticles dispersed in the agarose gel phantoms. Therefore, the presented results cast new light on the preparation of polydopamine-based magnetic theranostic nanomaterials, as well as on the proper methodology for investigation of magnetic nanoparticles in high field MRI experiments. The prepared material is a robust theranostic nanoasystem with great potential in nanomedicine.