Reflection removal detection enabled by single-pixel imaging through the semi-reflective medium.

Due to the substantial reflection information of the surrounding environment, it is difficult for a conventional camera to directly capture the distinct image behind without interference from the reflected virtual image through semi-reflective media such as an acrylic plate, glass, or water. Traditional reflective artifact removal methods either demand a major commitment of calculations or constrained photography conditions such as the use of a polarizer, which often degrades the performance of the reflection removal process and imposes a limitation on the application area. A different reflection removal method is investigated, where the interfering light rays can be attenuated effectively based on a differential calculation with a Fourier single-pixel imaging method. Experiments show that this method eliminates the interference caused by reflection from interfering objects and obtains clear images through an acrylic plate (with thicknesses of 1 mm, 2 mm, and 3 mm), glass (5 mm), and even transparent water (100 mm). Another experiment has been carried out to effectively image the target by removing the reflection through the glasses, which have the same thickness (1.1 mm) but different reflectivity (20%, 30%, 40%, and 50%).

Construction of photodynamic-effect immunofluorescence probes by a complex of quantum dots, immunoglobulin G and chlorin e6 and their application in HepG2 cell killing.

In this study, tri-functional immunofluorescent probes (Ce6-IgG-QDs) based on covalent combinations of quantum dots (QDs), immunoglobulin G (IgG) and chlorin e6 (Ce6) were developed and their photodynamic ability to induce the death of cancer cells was demonstrated. Strategically, one type of second-generation photosensitizer, Ce6, was first coupled with anti-IgG antibody using the EDC/NHS cross-linking method to construct the photosensitive immunoconjugate Ce6-IgG. Then, a complex of Ce6-IgG-QDs immunofluorescent probes was obtained in succession by covalently coupling Ce6-IgG to water soluble CdTe QDs. The as-manufactured Ce6-IgG-QDs maintained the bio-activities of both the antigen-antibody-based tumour targeting effects of IgG and the photodynamic-related anticancer activities of Ce6. By way of polyclonal antibody interaction with rabbit anti-human epidermal growth factor receptor (anti-EGFR antibody, N-terminus), Ce6-IgG-QDs were labelled indirectly onto the surface of human hepatocarcinoma (HepG2) cells in cell recognition and killing experiments. The results indicated that the Ce6-IgG-QDs probes have excellent tumour cell selectivity and higher photosensitivity in photodynamic therapy (PDT) compared with Ce6 alone, due to their antibody-based specific recognition and location of HepG2 cells and the photodynamic effects of Ce6 killed cells based on efficient fluorescence resonance energy transfer between QDs and Ce6. Copyright © 2015 John Wiley & Sons, Ltd.

Intracellular Biosynthesis of Fluorescent CdSe Quantum Dots in Bacillus subtilis: A Strategy to Construct Signaling Bacterial Probes for Visually Detecting Interaction Between Bacillus subtilis and Staphylococcus aureus.

In this work, fluorescent Bacillus subtilis (B. subtilis) cells were developed as probes for imaging applications and to explore behaviorial interaction between B. subtilis and Staphylococcus aureus (S. aureus). A novel biological strategy of coupling intracellular biochemical reactions for controllable biosynthesis of CdSe quantum dots by living B. subtilis cells was demonstrated, through which highly luminant and photostable fluorescent B. subtilis cells were achieved with good uniformity. With the help of the obtained fluorescent B. subtilis cells probes, S. aureus cells responded to co-cultured B. subtilis and to aggregate. The degree of aggregation was calculated and nonlinearly fitted to a polynomial model. Systematic investigations of their interactions implied that B. subtilis cells inhibit the growth of neighboring S. aureus cells, and this inhibition was affected by both the growth stage and the amount of surrounding B. subtilis cells. Compared to traditional methods of studying bacterial interaction between two species, such as solid culture medium colony observation and imaging mass spectrometry detection, the procedures were more simple, vivid, and photostable due to the efficient fluorescence intralabeling with less influence on the cells' surface, which might provide a new paradigm for future visualization of microbial behavior.

Inhibitory effects of CuInS2 and CdTe nanoparticles on macrophage cytokine production and phagocytosis in vitro.

Macrophages eliminate and destroy invading bacteria and contaminants by engulfing them or secreting cytokines that trigger downstream immune responses. Consequently, impairment of the phagocytic functions of macrophages and/or suppressing their cytokine secretion are dangerous to organisms that rely on immune protection. Accordingly, exposure to environmental nanoparticles (NPs) that display immunomodulatory properties are serious. In this work, two types of NPs, i.e., mild-toxicity CuInS2 NPs and high-toxicity CdTe NPs, were used to evaluate the effects of NP exposure for macrophages. Following incubation for 24 h, THP-1-derived macrophage viability was assessed using an MTT method after exposing the THP-1 cells to different concentrations of CuInS2 or CdTe NPs. Phagocytosis assays demonstrated that both CuInS2 and CdTe NPs impair phagocytic activity toward Staphylococcus aureus (S. aureus). After pretreatment with CuInS2 and CdTe NPs at 4 µmol/L, THP-1 macrophages exhibited decreases in phagocytic ratio from ca. 32.9% to ca. 18.5% and 18.7%, respectively. Since the zeta potentials of intact and weathered CuInS2 NPs were distributed over a wide range from positive to negative, large quantities of intact and weathered CuInS2 NPs bore sufficient positive charge on their surfaces to induce membrane depolarization, thus theoretically providing electrostatic forces between S. aureus and THP-1, which could induce downstream intracellular events that increase phagocytosis. However, real time polymerase chain reaction arrays revealed that transcription of the pro-inflammatory factors IL-1ß, IL-6, and TNF-α decreased while that of the anti-inflammatory factor IL-10 increased after treatment with CuInS2 NPs. Furthermore, transcription of TNF-α decreased while IL-10 increased after treatment with CdTe NPs. Thus, both kinds of NPs inhibited phagocytosis of S. aureus by THP-1 to some extent, confirming that immunosuppression can occur when macrophages are exposed to environmental NPs.