Fluorometric ‘switch-on’ detection of heparin based on a system composed of rhodamine-labeled chitosan oligosaccharide lactate, and graphene oxide

Abstract

A novel fluorescence 'Switch on' for the detection of heparin based on the RhB-COL/GO system was achieved. A strong fluorescence dye, Rhodamine B, was modified by chitosan oligosaccharide lactate (COL), which plays a major role in the formation of a positively charged RhB-COL complex. RhB-COL was soluble and stable in solution, which was characterized by using Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy. GO sheets quenched the fluorescence intensity of RhB-COL due to electron transfer from RhB to the GO surface. The decrease in fluorescence intensity of RhB-COL with increasing GO concentration was recorded using a Cary Eclipse fluorescence spectrophotometer. On the other hand, the addition of heparin replaced GO to bind with the RhB-COL surface via an electrostatic and noncovalent bond due to the abundant negative charge, which resulted in recovery of the fluorescence intensity. This RhB-COL/GO system possessed high selectivity and good sensitivity for the detection of heparin compared to other biomolecules, such as glycine, D-glucose, hyaluronic acid, L-glutamic acid, and ascorbic acid. The linear response toward heparin was measured over the range, 0-1.8 U · ml, with a low detection limit of 0.04 U · ml. The satisfactory sensing performance of RhB-COL/GO for heparin supports new 'switch-on' sensor applications in heparin-related biomedical detection.

Highly Selective Detection of Iodide in Biological, Food, and Environmental Samples Using Polymer-Capped Silver Nanoparticles: Preparation of a Paper-Based Testing Kit for On-Site Monitoring

“…It is expected that the −NH 2 group of COL was adsorbed on the surface of AgNPs. As we expected, the resolved NH peak intensity was decreased . These results confirmed the presence of COL on the surface of AgNPs.…”

“…31 The stretching frequency (ν) of CH was observed at 1386 cm –1 . 28,32−34 Further, we have characterized the COL-capped AgNPs by the FT-IR spectral technique. The FT-IR spectrum of COL-AgNPs shows the similar FT-IR characteristic peaks of COL (Figure 2A(b)).…”

“…Further, AgNPs show good conductivity, catalytic activity, chemical stability, and are extensively used in sensor, food storage, and textile industries. , The size- and distance-dependent SPR properties of AgNPs can help the researchers use it as a probe for sensor applications. , Chitosan oligosaccharide lactate (COL) is a degradable biopolymer. It is used in several fields, including water treatment, thin film and food industries, etc., due to their biocompatibility, nontoxicity, and good aqueous solubility. , Keeping these objectives in our minds, we have synthesized COL-capped silver nanoparticles (COL-AgNPs) at room temperature. Then, the COL-AgNPs were used as a probe for the selective detection of iodide.…”

On-Chip Synthesis of Hyaluronic Acid-Based Nanoparticles for Selective Inhibition of CD44+ Human Mesenchymal Stem Cell Proliferation

“…UV-vis spectrum of CS-RhB conjugate was detected in a range of wavelengths of 200-700 nm: according to literature RhB molecule exhibits a high absorption peak at 554 nm [44,57] while no peak is observed for CS in the same range of wavenumbers. CS-RhB spectrum showed the characteristic peak at 554 nm confirming effective conjugation between CS and RhB took place (data not reported).…”

“…where CS-RhB is the amount (mg) of the fluorescently labeled conjugate, RhB and CS are the starting raw materials amount (mg). CS-RhB conjugation was confirmed by UV-VIS spectrophotometer (Jenway™ 6705 Model), UV-vis spectrum of CS-RhB was scanned between 200 nm and 700 nm, pristine CS and RhB were used as control [44]. RhB labeling efficiency was determined by measuring the absorbance of CS-RhB conjugate solution with respect to RhB standard solutions at 554 nm in the concentration rank 0.25-4 µg/mL (R 2 = 0.9991).…”