A novel phosphatidylserine-functionalized AuNP for the visual detection of free copper ions with high sensitivity and specificity

Sensitive detection and intracellular imaging of free copper ions based on DNA-templated silver nanoclusters aggregation-inducing fluorescence enhancement effect

Free copper ions (Cu⁺ and Cu²⁺) have critical toxicity to cells, although copper is an essential element for human body. Hence, sensitive monitoring is crucial to avoid over intake of Cu⁺/Cu²⁺. We herein designed a ssDNA sequence (A₃₁) for synthetizing A₃₁-templated silver nanoclusters (AgNCs), and demonstrated that Cu⁺/Cu²⁺ can induce the aggregation of A₃₁-templated AgNCs and thus greatly enhanced the fluorescence emission of A₃₁-templated AgNCs. Based on Cu⁺/Cu²⁺-induced fluorescence enhancement effect of A₃₁-templated AgNCs, a label-free and signal-on fluorescent sensing platform was developed for the specific and sensitive detection of Cu⁺/Cu²⁺ in biological samples and intracellular imaging of Cu⁺/Cu²⁺ in cells. The signal-on fluorescent sensing platform could be used to rapidly detect Cu⁺ and Cu²⁺ with a detection limit of 0.1 µM within 30 min., and to perform the intracellular imaging of Cu⁺ and Cu²⁺ in cells with good cell permeability and biocompatibility. By using the signal-on fluorescent sensing platform, we have successfully detected Cu⁺ and Cu²⁺ in cells fluids and human serum with a recovery of 90-104% and a RSD (n = 5) < 5%, and performed the imaging of Cu⁺/Cu²⁺ in Hela cells. The developed fluorescent sensing platform has obvious analytical and imaging advantages such as signal-on, simple operation, short analysis time, both Cu⁺ and Cu²⁺ detection, similar or higher sensitivity, good cell permeability and biocompatibility, which promising a reliable approach for the rapid and on-site detection or imaging of free copper ions in biological samples in clinical diagnosis.

Phosphatidylserine-Gold Nanoparticles (PS-AuNP) Induce Prostate and Breast Cancer Cell Apoptosis

Prostate and breast cancer are the current leading causes of new cancer cases in males and females, respectively. Phosphatidylserine (PS) is an essential lipid that mediates macrophage efferocytosis and is dysregulated in tumors. Therefore, developing therapies that selectively restore PS may be a potential therapeutic approach for carcinogenesis. Among the nanomedicine strategies for delivering PS, biocompatible gold nanoparticles (AuNPs) have an extensive track record in biomedical applications. In this study, we synthesized biomimetic phosphatidylserine-caped gold nanoparticles (PS-AuNPs) and tested their anticancer potential in breast and prostate cancer cells in vitro. We found that both cell lines exhibited changes in cell morphology indicative of apoptosis. After evaluating for histone-associated DNA fragments, a hallmark of apoptosis, we found significant increases in DNA fragmentation upon PS-AuNP treatment compared to the control treatment. These findings demonstrate the use of phosphatidylserine coupled with gold nanoparticles as a potential treatment for prostate and breast cancer. To the best of our knowledge, this is the first time that a phosphatidylserine-capped AuNP has been examined for its therapeutic potential in cancer therapy.

Determination of copper ions in herbal medicine based on click chemistry using an electronic balance as a readout

The amount of copper affects the quality of herbal medicine greatly, it is necessary to develop some simple and sensitive methods to detect copper for the remote or resource-limited area. An electronic balance is one of the most familiar equipment that can be found nearly in all laboratories. The presence of Cu(i) can catalyze azide-alkyne cycloaddition reaction (called as click chemistry) with high efficiency. In this study, a simple method had been developed to detect copper ions in herbal medicine using an electronic balance as a readout device based on click chemistry. Cu(ii) is reduced to Cu(i) by sodium ascorbate in situ, which induces the "click" reaction between azido-DNA modified magnetic beads (MB-DNA) and alkynyl-DNA modified platinum nanoparticles (Pt NP-DNA) and results in the fixing of the platinum nanoparticles on the beads (called as MB-Pt NPs). MB-Pt NPs can be separated by a magnetic frame easily and transferred into a drainage reaction device containing hydrogen peroxide. Then, hydrogen peroxide can be decomposed by Pt NPs modified on MB to generate oxygen, which increases the pressure in the drainage reaction device and forces the water in the system to be discharged. The weight of the discharged water can be easily and accurately measured by an electronic balance. The weight of the water has a linear relationship with Cu(ii) in the range of 2.0-200 μM and a detection limit of 0.83 μM under 30 min of collected time. This method does not need complicated and expensive instruments, skilled technicians, and a complex data processing process. The proposed method had been applied to detect copper ions in herbal medicine with satisfactory results.

Ratiometric fluorescent paper sensor utilizing hybrid carbon dots-quantum dots for the visual determination of copper ions

A simple and effective ratiometric fluorescence nanosensor for the selective detection of Cu(2+) has been developed by covalently connecting the carboxyl-modified red fluorescent cadmium telluride (CdTe) quantum dots (QDs) to the amino-functionalized blue fluorescent carbon nanodots (CDs). The sensor exhibits the dual-emissions peaked at 437 and 654 nm, under a single excitation wavelength of 340 nm. The red fluorescence can be selectively quenched by Cu(2+), while the blue fluorescence is a internal reference, resulting in a distinguishable fluorescence color change from pink to blue under a UV lamp. The detection limit of this highly sensitive ratiometric probe is as low as 0.36 nM, which is lower than the U.S. Environmental Protection Agency (EPA) defined limit (20 μM). Moreover, a paper-based sensor has been prepared by printing the hybrid carbon dots-quantum dots probe on a microporous membrane, which provides a convenient and simple approach for the visual detection of Cu(2+). Therefore, the as-synthesized probe shows great potential application for the determination of Cu(2+) in real samples.

Phosphatidylserine-functionalized Fe3O4@SiO2 nanoparticles combined with enzyme-encapsulated liposomes for the visual detection of Cu2+

We reported on novel phosphatidylserine-functionalized Fe₃O₄@SiO₂ NPs and enzyme-encapsulated liposomes for the visual detection of Cu²⁺ by employing phosphatidylserine for Cu²⁺ recognition and the enzymatic catalysis/oxidation of TMB as a signal generator.

Metallic nanoparticles as synthetic building blocks for cancer diagnostics: from materials design to molecular imaging applications

Metallic nanoparticles have been a matter of intense exploration within the last decade due to their potential to change the face of the medical world through their role as 'nanotheranostics'. Their envisaged capacity to act as synthetic platforms for a multimodal imaging approach to diagnosis and treatment of degenerative diseases, including cancer, remains a matter of lively debate. Certain synthetic metal-based nanomaterials, e.g. gold and iron oxide nanoparticles, are already in clinical use or under advanced preclinical investigations following in vitro and in vivo preclinical imaging success. We surveyed the recent publications landscape including those reported metallic nanoparticles having established applications in vivo, as well as some of the new metallic nanoparticles which, despite their potential as cancer nanodiagnostics, are currently awaiting in vivo evaluation. The objective of this review is to highlight the current metallic nanoparticles and/or alloys as well as their derivatives with multimodal imaging potential, focusing on their chemistry as a springboard to discussing their role in the future of nanomedicines design. We also highlight here some of the fundamentals of molecular and nano-imaging techniques of relevance to the metal-based colloids, alloys and metallic nanoparticles discerning their future prospects as cancer nanodiagnostics. The current approaches for metallic and alloy surface derivatisation, aiming to achieve functional and biocompatible materials for multimodal bioimaging applications, are discussed in order to bring about some new perspectives on the efficiency of metallic nanoparticles as synthetic scaffolds for imaging probe design and forecast their future use in medical imaging techniques (optical, CT, PET, SPECT and MRI).

A simple and visible colorimetric method through Zr4+–phosphate coordination for the assay of protein tyrosine phosphatase 1B and screening of its inhibitors

Inhibitors of protein tyrosine phosphatase 1B (PTP1B) are promising agents for the treatment of type 2 diabetes and obesity, so a colorimetric method has been developed in this work for PTP1B assay and screening of its inhibitors.

Coupling a novel spiro-rhodamine B lactam derivative to Fe3O4 nanoparticles for visual detection of free copper ions with high sensitivity and specificity

A novel spiro-rhodamine B lactam derivative, which can be coupled to Fe₃O₄ NPs and act as a Cu²⁺-selective visual sensor is reported. It can be used to directly detect as little as 50 nM of Cu²⁺ in river or tap water by only naked-eye observation.