Simple fluorescence chemosensor for the detection of calcium ions in water samples and its application in bio-imaging of cancer cells

This article describes the design, synthesis and characterization of a sensor suitable for practical measurement of ionized calcium in water samples and cancer cells. Calcium is an important ion in living organs and works as a messenger in several cellular functions. A lack of Ca ions interrupts the immune system and can lead to several diseases. A novel magnetic-polydopamine nanoparticle (PDNP)/rhodamine B (RhB)/folic acid (FA) nanoparticle was developed for the determination of calcium ions in MCF 7 cell lysates and water samples. Furthermore, the produced nanoparticle was employed for bioimaging of folate receptor (FR)-overexpressed cancer cells. This nanoprobe displayed a bright photoluminescence emission at 576 nm under an excitation wavelength of 420 nm. In the presence of calcium ions, the fluorescence emission of the MNPs-PDNPs/RhB/FA probe was proportionally decreased from 20 ng mL(−1) to 100 ng mL(−1) and 0.5 μg mL(−1) to 20 μg mL(−1) with a lower limit of quantification (LLOQ) of about 20 ng mL(−1). The developed sensor showed a low-interference manner in the presence of possible coexistence interfering ions. In addition, this nanomaterial showed excellent biocompatibility with favorable differentiation ability to attach to the FR-positive cancer cells. The MNPs-PDNPs/RhB/FA nanoparticle has been utilized for bioimaging of the MCF 7 cell with favorable differentiation ability.