Synthesis and living cell imaging of a novel fluorescent sensor for selective cupric detection

Electrochemical Nanopipette Sensor for In Vitro/In Vivo Detection of Cu2+ Ions

In vitro/in vivo detection of copper ions is a challenging task but one which is important in the development of new approaches to the diagnosis and treatment of cancer and hereditary diseases such as Alzheimer's, Wilson's, etc. In this paper, we present a nanopipette sensor capable of measuring Cu2+ ions with a linear range from 0.1 to 10 μM in vitro and in vivo. Using the gold-modified nanopipette sensor with a copper chelating ligand, we evaluated the accumulation ability of the liposomal form of an anticancer Cu-containing complex at three levels of biological organization. First, we detected Cu2+ ions in a single cell model of human breast adenocarcinoma MCF-7 and in murine melanoma B16 cells. The insertion of the nanoelectrode did not result in leakage of the cell membrane. We then evaluated the distribution of the Cu-complex in MCF-7 tumor spheroids and found that the diffusion-limited accumulation was a function of the depth, typical for 3D culture. Finally, we demonstrated the use of the sensor for Cu2+ ion detection in the brain of an APP/PS1 transgenic mouse model of Alzheimer's disease and tumor-bearing mice in response to injection (2 mg kg-1) of the liposomal form of the anticancer Cu-containing complex. Enhanced stability and selectivity, as well as distinct copper oxidation peaks, confirmed that the developed sensor is a promising tool for testing various types of biological systems. In summary, this research has demonstrated a minimally invasive electrochemical technique with high temporal resolution that can be used for the study of metabolism of copper or copper-based drugs in vitro and in vivo.

Recent research progress in galactose-based fluorescent probes for detection of biomarkers of liver diseases

This highlight illustrates the challenges and latest progress in galactose-based fluorescent probes for early diagnosis of liver diseases.

Condensation Product of p-anisaldehyde and L-phenylalanine: Fluorescent "on-off" Sensor for Cu2+ and IMPLICATION Logic Gate

(Z)-2-(4-methoxybenzylideneamino)-3-phenylpropanoic acid (L) synthesized by condensation of p-anisaldehyde and L-phenylalanine acts as selective fluorescent as well as voltammetric sensor for Cu²⁺ in 2:1 (v/v) CH₃OH:H₂O. The fluorescence intensity of L (λ_max 425 nm) is quenched ca. 65% by Cu²⁺. Metal ions - Li⁺, Na⁺, K⁺, Al³⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Mn²⁺, Ni²⁺ and Pb²⁺ do not interfere. The binding constant and the detection limits were calculated to be 0.56 × 10² M^-1 and 10^-6 M respectively. DFT and TDDFT calculations confirmed 2:1 binding stoichiometry between L and Cu²⁺ obtained from fluorescence data. The interaction between L and Cu²⁺ is reversible for many cycles with respect to ethylenediamine tetraacetate anion (EDTA^2-) which results in IMPLICATION logic gate.