No abstract

To achieve an accurate diagnosis and efficient tumor treatment, developing a facile and powerful strategy to build multifunctional nanotheranostics is highly desirable. Benefiting from the distinct characteristics of black phosphorus quantum dots (BPQDs), herein, a versatile nanoprobe (H-MnO 2 / DOX/BPQDs) is constructed for dual-modality cancer imaging and synergistic chemo-phototherapy. The hollow mesoporous MnO 2 (H-MnO 2 ) nanoparticles are sequentially decorated with a cationic polymer poly (allylamine hydrochloride) (PAH) and an anionic polymer poly (acrylic acid) (PAA). The obtained H-MnO 2 -PAH-PAA is covalently grafted with BPQDs-PEG-NH 2 via a carbodiimide cross-linking reaction and then loaded with anti-cancer drug DOX to form final nanoprobe H-MnO 2 /DOX/BPQDs. Under the tumor microenvironment, H-MnO 2 /DOX/BPQDs is degraded to release encapsulated functional molecules DOX and BPQDs. DOX acts as the chemotherapy and fluorescence imaging agent, and BPQDs endows the nanoprobe with photodynamic therapy (PDT) and photothermal therapy (PTT) abilities under dual laser irradiation of 630 and 808 nm. H-MnO 2 offers contrasts for magnetic resonance imaging (MRI) and facilitates conversion of endogenous H 2 O 2 to oxygen, thereby relieving tumor hypoxia and enhancing PDT efficacy. All in vitro and in vivo results demonstrate that the designed nanoprobe displays dual-modality MRI/FL imaging and synergistic chemotherapy/PDT/PTT, which ultimately enhances the accuracy of cancer diagnosis and therapeutic performance.

An enzyme-free titer plate-based colorimetric assay utilizing functionalized mesoporous silica nanoparticles (MSNs) entrapping pH-indicator molecules has been developed. Pores in the silica nanoparticles were functionalized with phenyltrimethyloxysilane so that pH indicator molecules (thymolphthalein or TP in the present case) can be tightly entrapped through π-π conjugation. To detect prostate specific antigen (PSA), the TP-containing MSNs were coated with polyethylenimine (PEI), which favors the attachment of the negatively charged secondary anti-PSA antibody. The entrapped thymolphthalein molecules can be readily released from the pores with a simple addition of alkaline solution. The resultant bifunctional MSNs were used for signal-amplified detection of PSA captured by the primary antibody preimmobilized in the wells of a plate. Our method possesses a wide dynamic range (0.5 to 8000 pg/mL) wherein the adsorption of the bifunctional MSNs obeys a modified Langmuir isotherm. A detection limit (LOD) down to as low as 0.36 pg/mL can be attained. Owing to the size uniformity of the MSNs and the obviation of enzyme molecules employed in the enzyme-linked immunosorbent assay (ELISA), excellent reproducibility (RSD = 1.12%) was achieved. The selective detection of PSA in human serum samples demonstrates the amenability of our method to detect important biomarkers in complex biological samples, whereas the performance of the assay in a titer plate ensures high throughput and obviates the use of expensive instruments. Both of these features are prerequisites for clinical settings wherein a great number of samples need to be analyzed in a timely fashion.

This work reports an electrofluorochromic strategy on the basis of electric field control of fluorescent signal generation on bipolar electrodes (BPEs) for visualizing cancer cell surface glycoprotein (mucin 1). The device included two separate cells: anodic sensing cell and cathodic reporting cell, which were connected by a screen-printing electrode patterned on poly­(ethylene terephthalate) (PET) membrane. In the sensing cell, anti-MUC1 antibody immobilized on a chitosan-multiwalled carbon nanotube (CS-MWCNT)-modified anodic BPE channel was used for capturing mucin-1 (MUC1) or MCF-7 cancer cells. Then ferrocene (Fc)-labeled mucin 1 aptamers were introduced through hybridization. Under an applied voltage, the ferrocene was oxidized and the electroactive molecules of 1,4-benzoquinone (BQ) in the cathodic reporting cell were reduced according to electroneutrality. This produced a strongly basic 1,4-benzoquinone anion radical (BQ•–), which turned on the fluorescence of pH-responsive fluorescent molecules of (2-(2-(4-hydroxystyryl)-6-methyl-4H-pyran-4-ylidene)­malononitrile) (SPM) coexisting in the cathode reporting cell for both spectrophotometric detection and imaging. This strategy allowed sensitive detection of MUC1 at a concentration down to 10 fM and was capable of detecting a minimum of three MCF-7 cells. Furthermore, the amount of MUC1 on MCF-7 cells was calculated to be 6.02 × 104 molecules/cell. Our strategy also had the advantages of high temporal and spatial resolution, short response time, and high luminous contrast and is of great significance for human health and the promotion of life science development.

The low solubility of oxygen in solution is the main obstacle for the biodegradation of organic pollutants in wastewater. To address this problem, inspired by the degradation mechanism of aerobic bacteria toward organic pollutants, a novel photodegradation system was presented and operated by a heterojunction photocatalyst combining with a hydrophobic triphase interface, allowing oxygen to directly diffuse from the gas phase to active catalytic sites submersed in polluted solutions. Especially, the heterojunction photocatalyst was fabricated by graphitic carbon nitride nanosheets (C 3 N 4 NS) sensitized with 5,10,15,20-tetrakis(4-carboxylphenyl)porphyrin (TCPP). The resulting photocatalyst was coated on a certain part of the commercial superhydrophobic carbon paper (CP) and submersed in the polluted wastewater, while the other part of hydrophobic CP (without coating with C 3 N 4 -TCPP nanocomposite) was exposed to air to form a gas−liquid−solid tri-phase photodegradation system. With this system, the photodegradation rate was 10-fold higher than that of a conventional liquid/solid diphase system in oxygen-saturated solutions. This was, on one hand, due to the abundant oxygen on the surface of a photocatalyst coming from the fast and direct diffusion from the gas phase through the superhydrophobic nanoporous part of CP. On the other hand, the hybrid C 3 N 4 -TCPP nanocomposite enhanced the light absorption efficiency under simulated sunlight irradiation and restrained the recombination of photogenerated electron−hole. Moreover, the triphase photodegradation system was stable in aqueous solutions for a long time and can be reused almost without attenuation for five cycles, which provided a great potential to be utilized for practical wastewater treatment.