Acridine orange coated magnetic nanoparticles for nucleus labeling and DNA adsorption

Adenine imprinted beads as a novel selective extracellular DNA extraction method reveals underestimated prevalence of extracellular antibiotic resistance genes in various environments

Despite severe threats of extracellular antibiotic resistance genes (eARGs) towards public health in various environments, advanced studies have been hindered mainly by ineffective extracellular DNA (exDNA) extraction methods, which is challenged by trace levels of exDNA and inference from abundant coexisting compounds. This study developed a highly selective exDNA extraction method based on molecular imprinting technology (MIT) by using adenine as the template for the first time. Results suggested that adenine imprinted beads were rough spheres at an average size of 0.39 ± 0.07 μm. They effectively adsorbed DNA in the absence of chaotropic agents, with superior capacity (796.2 mg/g), rate (0.0066/s) and regarding DNA of variable lengths, even the ultra-short DNA (<100 bp). They were also highly selective towards DNA, circumventing the interference of competitive compounds' interference. These properties contribute to efficient exDNA extraction (71 %-119 %) from various environmental samples. Specifically, adenine imprinted beads enabled significantly higher extraction rates of eARGs from river, air and vegetable samples (69 %-95 %) compared to that by commercial DNA extraction products (16 %-62 %). The adenine imprinted beads-based method reveals underestimated eARG levels in the environment and the corresponding risks, and thus will thus be a powerful tool for advanced exDNA research.

Biosorption of organic dye Acridine orange from aqueous solution using dry biomass of Bacillus cereus M116

Acridine orange (AO), a basic carcinogenic fluorochrome dye, is used in the industry for staining. In this study, Gram-positive bacteria, Bacillus cereus M¹₁₆ (MTCC 5521) dry biomass was tested as an eco-friendly, easily available, and cheap biosorbent for the AO dye removal. We obtained optimum biosorption of AO at a biomass concentration of 0.25 g/L and initial dye concentrations of 50-400 mg/L at neutral to basic pH within the 300 min contact time. Kinetics analysis of the biosorption process was best fitted with the pseudo-second-order reaction type. We also performed the isotherm analysis to predict the nature of the reaction taking place, which was found to follow the Redlich Peterson isotherm model with high determination coefficients. The maximum sorption capacity was 210.46 mg/g of dry biomass. The differential FTIR spectroscopic analysis of pristine and AO-treated Bacillus cereus M¹₁₆ cells suggested the potential involvement of carbonyl, hydroxyl, and amine groups in the biosorption process. Also, the scanning electron microscopy of the cells after AO removal confirmed a gross surface alteration compared to the untreated cells. Furthermore, Response Surface Model (RSM) analysis with the three-way ANOVA test confirms statistically significant interactions between the dye concentration, pH, and temperature with the biosorption capacity (p < 0.001). Hence, the dry biomass of Bacillus cereus M¹₁₆ was found to be an effective bio-remedial for the AO removal.

Combinatorial delivery of doxorubicin and acridine orange by gold core silica shell nanospheres functionalized with poly(ethylene glycol) and 4-methoxybenzamide for cancer targeted therapy

Combinatorial therapies based on the simultaneous administration of multiple drugs can lead to synergistic effects, increasing the efficacy of the cancer therapy. However, it is crucial to develop new delivery systems that can increase the drugs' therapeutic selectivity and efficacy. Gold core silica shell (AuMSS) nanoparticles present physicochemical properties that allow their simultaneous application as drug delivery and imaging agents. Herein, poly(ethylene glycol) was modified with 4-methoxybenzamide and 3-(triethoxysilyl)propyl isocyanate (TPANIS) to create a novel surface functionalization capable of improving the colloidal stability and specificity of AuMSS nanospheres towards cancer cells. Moreover, a dual drug combination based on Doxorubicin (DOX) and Acridine orange (AO) was characterized and administered using the AuMSS-TPANIS nanospheres. The obtained results show that the DOX:AO drug combination can mediate a synergistic therapeutic effect in both HeLa and MCF-7 cells, particularly at the 2:1, 1:1, and 1:2 ratios. Additionally, the TPANIS functionalization increased the AuMSS nanospheres colloidal stability and selectivity towards MCF-7 cancer cells (overexpressing sigma receptors). Such also resulted in an enhanced cytotoxic effect against MCF-7 cells when administering the DOX:AO drug combination with the AuMSS-TPANIS nanospheres. Overall, the obtained results confirm the therapeutic potential of the DOX:AO drug combination as well as the targeting capacity of AuMSS-TPANIS, supporting its application in the cancer-targeted combinatorial chemotherapy.

Optical-Based (Bio) Sensing Systems Using Magnetic Nanoparticles

In recent years, various reports related to sensing application research have suggested that combining the synergistic impacts of optical, electrical or magnetic properties in a single technique can lead to a new multitasking platform. Owing to their unique features of the magnetic moment, biocompatibility, ease of surface modification, chemical stability, high surface area, high mass transference, magnetic nanoparticles have found a wide range of applications in various fields, especially in sensing systems. The present review is comprehensive information about magnetic nanoparticles utilized in the optical sensing platform, broadly categorized into four types: surface plasmon resonance (SPR), surface-enhanced Raman spectroscopy (SERS), fluorescence spectroscopy and near-infrared spectroscopy and imaging (NIRS) that are commonly used in various (bio) analytical applications. The review also includes some conclusions on the state of the art in this field and future aspects.

New applications of the acridine orange fluorescence staining method: Screening for circulating tumor cells

The aim of the present study was to explore use of the acridine orange fluorescence (AO-F) staining method for screening of circulating tumor cells (CTCs) in renal cell carcinoma (RCC) patients. The AO-F positive staining rate of live and dead tumor cells was calculated. The positive staining rate in the live group was 93.4±3.0%, while the dead group failed to emit specific fluorescence. A known number of tumor cells were added to peripheral blood, and the detection sensitivity of the four groups (50, 100, 200 and 500 cells/tube) was 10.2±3.8, 9.2±2.3, 10.8±2.6 and 10.5±1.9%, respectively. The average detection sensitivity of the four groups was 10.16±2.73%. There was a positive correlation between the number of cells that was positively stained with AO-F and the total number cells in the system (χ²=0.959; P<0.001). Subsequently, the AO-F staining method was used to detect positive staining cells in 8 healthy volunteers (control group), and 112 non-metastatic and 27 metastatic RCC patients. The positive staining rate was 13.67% (19/139) in RCC patients, while none of the control group was positive. The AO-F positive staining rate was not significantly different between the metastatic and non-metastatic patients according to age, gender, the pathological pattern, T2/3 (according to the Tumor-Node-Metastasis classification) or Fuhrman grade, while there was a significant difference according to T1. The positive staining rate was 8.93% (10/112) for non-metastatic patients and 33.33% (9/27) for metastatic patients, which showed a significant difference (P<0.05). In 112 non-metastatic and 27 metastatic patients, the positive staining rate was not significantly associated with gender, age, tumor size, the pathological pattern, T classification, Fuhrman grade, the presence of a lesion or metastasis to the lungs. The present study demonstrated that the method of CTC staining with AO-F, which has high reproducibility and specificity, was feasible for identifying CTCs and warrants further study.

Magnetic nanoparticles with fluorescence and affinity for DNA sensing and nucleus staining

The fluorescence magnetic nanoparticles offer versatile platforms for nucleus imaging and DNA adsorption.

Multifunctional fluorescent magnetic nanoparticles for lung cancer stem cells research

In this paper, a multifunctional peptide-fluorescent-magnetic nanocomposites (Fe₃O₄@PEI@Cy5.5@PEG@HCBP-1 NPs) was synthesized via a layer-by-layer approach for potential application to cancer diagnoses. The multifunctional nanocomposites have great dispersibility and homogeneous particle sizes in aqueous solution. Meanwhile, it has perfect hemocompatibility and satisfying cytocompatibility in a relatively high concentration. Data from in vitro cytotoxicity assay indicated that the nanocomposites could recognize the lung cancer stem cells (CSCs) specifically and enrich the HCBP-1 positive CSCs from H460 tumor xenografts effectively. Additionally, the results of in vivo live fluorescent imaging and magnetic resonance imaging (MRI) showed that the nanocomposites could identify lung CSCs in tumor xenografts. These results suggested that the nanocomposites could be used as a potential cancer diagnostic agent through modifying diverse fluorescence dyes and targeting ligands on its surface.

Superparamagnetic core/shell nanostructures for magnetic isolation and enrichment of DNA

Fe₃O₄ magnetic nanoparticles (MNPs) are promising candidates for various biomedical applications due to their extraordinary properties.

Detection of Staphylococcus aureus using acridine orange-doped silica nanoparticles as a fluorescent label

A rapid, simple, and efficient fluorescence measurement method for S. aureus detection was developed by using a novel AO@SiO₂–NH₂ fluorescent nanoparticles.