Performance Enhancement of Electrochemiluminescence with the Immunosensor Controlled Using Magnetized Masks for the Determination of Epithelial Cancer Biomarker EpCAM.

The performance of an electrochemiluminescence (ECL) immunosensor was improved with a particle gradient. SiO2-coated magnetic beads were adopted as nanocarriers for gradient manipulation and immobilized with the primary antibody. Cadmium telluride quantum dots were coated with a layer of protein G for conjugation and orientation of the secondary antibody as signal labels. ECL immunosensor gradients on the electrode were formed by magnetolithography (ML) with magnetized nickel masks of column and stripe arrays. The immunosensor generally aggregated as an island on the substrate, leading to a decrease of efficiency in the characteristic signals. Stripe arrays of magnetized nickel were designed to generate cylindrical magnetic flux on the substrate to improve the particle manipulation with the gradient. Various gradients of the sandwich-structured immunosensor substantially affected the electrochemical performance. Compared to the gradient-free immunosensor, the gradient of the immunosensor generated by ML using a 3 µm stripe array mask enhanced the ECL intensity ∼2.2 times. The results of quantification of epithelial cell adhesion molecules (EpCAM) with the gradient immunosensor showed a broad linear range (15-420 pg mL-1), a low limit of detection (5.5 pg mL-1), and high reliability for EpCAM-spiked serum samples, indicating that the immunosensor gradient substantially enhances the performance of the ECL assay.

A dimedone-phenylalanine-based fluorescent sensor for the detection of iron (III), copper (II), L-cysteine, and L-tryptophan in solution and pharmaceutical samples.

The development of fluorescence molecules for the fast and effective detection of L-tryptophan (L-Trp) has attracted a lot of attention because it is an important amino acid for baby growth, nitrogen equilibrium in adults, improving sleep, and mood regulation. A dimedone-phenylalanine-based chiral sensor (SDPA) was synthesized and exhibited a strong fluorescence quenching by Fe3+ and Cu2+ in a water/DMSO (3/7) solution with a detection limit of 2.29 × 10-6 M and 6.37 × 10-6 M, respectively. The factors affecting fluorescence sensings, such as the pH and competing cations, were studied. The sensor can be reused at least five times after being treated with EDTA. The Job plot, ESI-MS spectra, 1H NMR spectra, absorbance, and fluorescence titration experiments were investigated to study the mechanism of SDPA-Fe3+ and SDPA-Cu2+ complexation. The SDPA-Cu2+ complex can detect L-tryptophan and L-cysteine at trace levels by turn-on fluorescence with a detection limit of 9.35 × 10-6 M and 8.86 × 10-6 M, respectively. Moreover, applying the SDPA-Cu2+ complex for quantitative analysis of L-tryptophan in real sleep-improving capsules resulted in good recovery. The L-tryptophan level of the Elining capsule was determined at 190.8 ± 10.5 mg/g (mg L-tryptophan/g medicine), which is close to the announced quantity of 180 mg/g. Besides, the SDPA-Cu2+ complex can selectively detect free L-Try molecules and L-Try residues in proteins.

Naked-eye colorimetric and turn-on fluorescent Schiff base sensor for cyanide and aluminum (III) detection in food samples and cell imaging applications.

A new efficient Schiff base sensor SB3 for fluorescent and colorimetric "naked-eye" "turn-on" sensing of cyanide anion (CN-) with excellent sensitivity and selectivity was developed. The 4,4'-(perfluoropropane-2,2-diyl)bisphenol group and two phenyl groups were covalently linked by two C = N bonds to extend the conjugation length. The four hydroxyl groups can improve the water solubility of the SB3 sensor. The SB3 sensor exhibited high specificity towards CN- by interrupting its intramolecular charge transfer, resulting in a color change and remarkable "turn-on" green fluorescence emission. The sensing mechanism is caused by the nucleophilic addition of CN- toward imine groups of the SB3 sensor, leading to breaks of the conjugation, fluorescent spectral changes, and color change. It was confirmed by 1H NMR titration and Mass spectra. The detection limits for CN- and Al3+obtained by fluorescence spectrum are 0.80 µM and 0.25 µM, respectively. The SB3 sensor can act as an efficient chemical sensor for detecting the CN- and Al3+ ions under common environmental and physiological conditions (pH 5-12). Besides, the sensor can also detect CN- in food materials (such as sprouting potatoes and cassava flour) and imaging CN-in living cells with strong "turn-on" fluorescence at 490 nm. SB3 is an excellent CN- sensor that exhibits some advantages, including easy synthesis, distinct fluorescence and color change, high selectivity, low detection limit, and good anti-interference ability to analyze solution and food samples, together with fluorescence cell imaging.

An aniline trimer-based multifunctional sensor for colorimetric Fe3+, Cu2+ and Ag+ detection, and its complex for fluorescent sensing of L-tryptophan.

The detection of metal ions and amino acids by the aniline oligomer-based receptor has not been reported yet, to the best of our knowledge. In this study, an efficient multifunctional cation-amino acid sensor (CAS) with aniline moiety and chiral thiourea binding site was synthesized by the reaction of aniline trimer and (S)-(+)-1-phenyl ethyl isothiocyanate. CAS can sense Fe3+, Cu2+, Ag+ ions, and L-tryptophan. These results can be recognized by the naked eye. The appropriate pH range for the quantitative analysis of Fe3+, Cu2+, and Ag+ by CAS in DMSO/water (30 vol% water) was evaluated. The interaction between CCS and metal ions was analyzed by 1H NMR titration. The detection limits of CAS for the Cu2+, Ag+, and Fe3+ were 0.214, 0.099, and 0.147 µM, respectively. Moreover, the CASCu2+ complex can act as a turn-on fluorescence sensor for L-tryptophan. On the contrary, there is no response upon the addition of other amino acids, such as L-histidine, L-proline, L-phenylalanine, L-threonine, L-methionine, L-tyrosine, and L-cystine to CASCu2+ complex.

Recent Developments about Conductive Polymer Based Composite Photocatalysts.

Conductive polymers have been widely investigated in various applications. Several conductive polymers, such as polyaniline (PANI), polypyrrole (PPy), poly(3,4-ethylenedioxythiophene) (PEDOT)), and polythiophene (PTh) have been loaded with various semiconductor nanomaterials to prepare the composite photocatalysts. However, a critical review of conductive polymer-based composite photocatalysts has not been available yet. Therefore, in this review, we summarized the applications of conductive polymers in the preparation of composite photocatalysts for photocatalytic degradation of hazardous chemicals, antibacterial, and photocatalytic hydrogen production. Various materials were systematically surveyed to illustrate their preparation methods, morphologies, and photocatalytic performances. The synergic effect between conductive polymers and semiconductor nanomaterials were observed for a lot of composite photocatalysts. The band structures of the composite photocatalysts can be analyzed to explain the mechanism of their enhanced photocatalytic activity. The incorporation of conductive polymers can result in significantly improved visible-light driven photocatalytic activity by enhancing the separation of photoexcited charge carriers, extending the light absorption range, increasing the adsorption of reactants, inhibiting photo-corrosion, and reducing the formation of large aggregates. This review provides a systematic concept about how conductive polymers can improve the performance of composite photocatalysts.

Exploring the Behavior of Bovine Serum Albumin in Response to Changes in the Chemical Composition of Responsive Polymers: Experimental and Simulation Studies.

Knowledge of the interactions between polymer and protein is very important to fabricate the potential materials for many bio-related applications. In this regard, the present work investigated the effect of copolymers on the conformation and thermal stability of bovine serum albumin (BSA) with the aid of biophysical techniques such as fluorescence spectroscopy, circular dichroism (CD) spectroscopy and differential scanning calorimetry (DSC). In comparison with that of copolymer PGA-1.5, our fluorescence spectroscopy results reveal that the copolymer PGA-1, which has a lower PEGMA/AA ratio, shows greater influence on the conformation of BSA. Copolymers induced unfolding of the polypeptide chain of BSA, which was confirmed from the loss in the negative ellipticity of CD spectra. DSC results showed that the addition of PGA-1 and PGA-1.5 (0.05% (w/v) decreased the transition temperature by 14.8 and 11.5 °C, respectively). The results from the present study on the behavior of protein in response to changes in the chemical composition of synthetic polymers are significant for various biological applications such as enzyme immobilization, protein separations, sensor development and stimuli-responsive systems.

Label-free DNA detection using two-dimensional periodic relief grating as a visualized platform for diagnosis of breast cancer recurrence after surgery.

In this study we fabricated a nanopillar array of silicon oxide, involving very-large-scale integration (VLSI) and reactive ion etching (RIE), as two-dimensional periodic relief gratings (2DPRGs) on Si surfaces. Thiolated oligonucleotide was successively immobilized on the thiol functionalized surfaces of 2DPRGs by disulfide bond as an optical probe to detect a human genomic DNA (hgDNA584), related to breast cancer recurrence after surgery, from a biological specimen. The oligonucleotide-bound 2DPRG alone produces insignificant structure change, but upon hybridization with hgDNA584 leads to a dramatic change of the pillar scale due to hgDNA584 filling inside the 2DPRG layers. The performance of the sensor was evaluated by capturing hgDNA584 on the oligonucleotide-bound 2DPRGs and measuring the effective refractive index (neff), resulting of color change from pure blue to red, observed by naked eyes along an incident angle of 20-30°. The surface-bound 2DPRG based assay with the chemoresponsive diffraction grating signal transduction scheme results in an experimentally simple DNA detection protocol, displaying attributes of both detection methodologies: the high sensitivity and selectivity afforded by 2DPRG probes and the experimental simplicity, and miniaturization potential provided by the diffraction-based sensing technology.

Ultraviolet-durable superhydrophobic zinc oxide-coated mesh films for surface and underwater-oil capture and transportation.

In this paper, we report a simple and an inexpensive method for fabricating superhydrophobic/superoleophilic mesh films from microstructured ZnO coatings. The microstructured ZnO coatings, which do not contain any fluorinated compounds, maintain their superhydrophobicity and superoleophilicity after ultraviolet irradiation and display environmental stability. Furthermore, those microstructured ZnO-coated mesh films exhibit good selectivity (even underwater) and excellent recyclability, making them promising candidates for many potential applications, including liquid-liquid separation, water treatment, and liquid transportation.

Bioconjugated fluorescent polymeric nanoparticles for imaging and targeted therapy of HER2-overexpressing cancer cells.

We report the development of Herceptin-conjugated fluorescent polymeric nanoparticles (PNp) probes. Synthesis of fluorescent conjugated polymer as the core, preparation of the core/shell PNp, the ability of immobilizing Herceptin on PNp, targeting and imaging of bioconjugated PNp toward HER2-overexpressing cancer cells, and therapeutic effect on cell cycle, together with the expression of apoptosis related proteins, were investigated. We have achieved active tumor targeting by rapid PNp-antibody binding to tumor-specific antigens. Besides, Herceptin-conjugated PNp can suppress the growth of HER2-overexpressing cancer cells.

Preparation and non-invasive in-vivo imaging of anti-adhesion barriers with fluorescent polymeric marks.

Comb-like PEMLn polymers with pendent PEG-PLLA side chains were synthesized as tissue anti-adhesion barriers. The comb-like structure improved the flexibility of the films. Fluorescent polymer-biocompatible polymer guest-host materials were printed on the films as marking dots. Without sacrificing rats on different days after surgery, degradation behaviors of the marked films can be investigated non-invasively in the in-vivo imaging system (IVIS) by monitoring the location of fluorescent signals. Degradation properties of PEML1/G26L35 films were adjusted by incorporating G26L35 oligomers. PEML1 and PEML1/G26L35 films were very effective in preventing post-surgical tissue-adhesions. Degradation behaviors of various films observed in the animal study were consistent with those investigated by the in-vivo imaging method. Fluorescent polymer/biocompatible polymer blends were promising candidates for in-vivo imaging applications.