Synthesis and characterization of NaYF4:Yb3+,Er3+@silica-N=folic acid nanocomplex for bioimaginable detecting MCF-7 breast cancer cells

Crystal defect induced zero thermal quenching β-NaYF4: Eu3+, Sm3+ red-emitting phosphor

Red phosphors with brilliant performance are crucial for the application of white LEDs as their red-light component. However, the thermal quenching phenomenon is an inevitable obstacle in the practical application of various types of red-light phosphors. In this study, we report the preparation of a novel type of phosphor, NaYF4: 0.065Eu3+, 0.002Sm3+, possessing not only an energy transfer effect from Sm3+ to Eu3+ but also superior negative thermal quenching (NTQ) performance. The phosphor was synthesized via a one-step hydrothermal method, resulting in a prominent improvement in its luminous thermal stability supported by NTQ. The NTQ originated from the thermal stimulation excitement of the captured electrons in electronic traps, which is attributed to the non-equivalence between the different types of ions. The shape of the emission spectrum measured at high temperature was identical to that measured at room temperature, which not only showed the remarkable thermal stability of this novel type of phosphor but also the promising prospect of its practical application. This finding will contribute to improving the thermal stability of phosphor materials doped with lanthanide elements.

Amino-functionalized cross-linked cellulosic fabric with antibacterial, UV protection, and coloring effects using folic acid

The amino-functionalized cellulose with folic acid, via an esterification reaction between carboxylic acid of folic acid and hydroxyl groups of cellulose, can develop multifunctional products with new chemical and physical properties. Folic acid contains two carboxylic groups as well as an amine group that can be used as a coupling agent and provide suitable conditions for coupling hydroxyl-based compounds to cellulose. Also; the multi-functionalized cellulose with folic acid has no effects on the physical and mechanical properties and also has benefits such as antibacterial, UV protection, and wrinkle resistance. The FTIR-ATR and Raman analysis confirmed the amino functionalized-cellulosic fabric via an esterification reaction between cellulose and folic acid. The cell viability of L929 fibroblast (NCBI C161) and MCF-7 (NCBI C135) cancer cells indicated more effectiveness on MCF-7 cancer cells. Therefore; folic acid can be used as a biocompatible natural cross-linker to modify cellulose fabrics for apparel and medical applications.

Upconversion NaYF4:Yb3+/Er3+@silica-TPGS Bio-Nano Complexes: Synthesis, Characterization, and In Vitro Tests for Labeling Cancer Cells

Fluorescence imaging is an important technique used for early diagnosis and effective treatment of some incurable diseases including cancer. Herein, we report novel NaYF₄:Yb³⁺/Er³⁺@silica-TPGS bio-nano complexes for labeling cancer cells. The NaYF₄:Yb³⁺/Er³⁺ nanoparticles have been successfully synthesized via a hydrothermal route, further coated with a silica shell, and functionalized with d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS). The experimental results indicate that NaYF₄:Yb³⁺/Er³⁺@silica-TPGS emits stronger upconversion luminescence than NaYF₄:Yb³⁺/Er³⁺ under an excitation of 980 nm. More significantly, the NaYF₄:Yb³⁺/Er³⁺@silica-TPGS bio-nano complexes could strongly label MCF-7 breast cancer cells for in vitro experiments detected by a fluorescence microscope. On the other hand, the complex could not typically probe healthy cells, which are HEK-293A human embryonic kidney cells, under the same experimental conditions. Because of their strong upconversion luminescence, good dispersibility, and biocompatibility, NaYF₄:Yb³⁺/Er³⁺@silica-TPGS bio-nano complexes can be a promising candidate/probe for biomedical labeling and diagnostics.

Inner filter effect between upconversion nanoparticles and Fe(ii)-1,10-phenanthroline complex for the detection of Sn(ii) and ascorbic acid (AA)

Dual-function and multi-function sensors can use the same material or detection system to achieve the purpose of detection of two or more substances. Due to their high sensitivity and specificity, dual-function and multi-function sensors have potential applications in many fields. In this article, we designed a dual-function sensor to detect Sn(ii) and ascorbic acid (AA) based on the inner filter effect (IFE) between NaYF₄:Yb,Er@NaYF₄@PAA (UCNPs@PAA) and Fe(ii)–1,10-phenanthroline complex. Fe(ii)–1,10-phenanthroline complex has strong absorption in most of the ultraviolet-visible light range (350 nm–600 nm), and this absorption band overlaps with the green emission peak of UCNPs@PAA at 540 nm; Fe(ii)–1,10-phenanthroline complex can significantly quench the green light emission of UCNPs@PAA. When Sn(ii) or AA is added to the UCNPs@PAA/Fe(iii)/1,10-phenanthroline, they can reduce Fe(iii) to Fe(ii). Fe(ii) can react with 1,10-phenanthroline to form an orange complex, thereby quenching the green light emission of UCNPs@PAA. And the quenching efficiency is related to the concentration of Sn(ii) and AA; there is a linear relationship between quenching efficiency and the concentration of Sn(ii) and AA, within a certain concentration range the detection limits of this dual-function sensor for Sn(ii) and AA are 1.08 μM and 0.97 μM, respectively. In addition, the dual-function sensor can also detect Sn(ii) and AA in tap and spring water.

Based on the inner filter effect (IFE), we use UCNPs to develop a dual-function sensors, which can realize sensitive and selective detection for the Sn(ii) and ascorbic acid (AA).