Concanavalin A-conjugated gold nanoparticle/silica quantum dot (AuNPs/SiQDs-Con A)-based platform as a fluorescent nanoprobe for the bioimaging of glycan-positive cancer cells

Advanced photoluminescent nanomaterials for targeted bioimaging of cancer cells

The investigation of changes in the membrane of cancer cells holds great potential for biomedical applications. Malignant cells exhibit overexpression of receptors, which can be used for targeted drug delivery, therapy, and bioimaging. Targeted bioimaging is one the most accurate imaging methods with a non-invasive nature, allowing for localization of the malignant cell without disrupting cellular integrity. Also, bioimaging has the potential to enhance the quality of established imaging techniques like magnetic resonance imaging (MRI). The utilization of nanoparticles in targeted bioimaging enhances the imaging quality and efficiency. Biocompatible nanoparticles can easily penetrate cell membranes, while they can be readily functionalized on their surfaces toward cell receptors. This study reviews reports on the application of new advanced photoluminescent materials for targeted bioimaging using the cell membrane receptors. Also, the limitations and advantages of the application of nanoparticles have been reviewed along with the clinical consideration of their uses in bioimaging.

A facile synthesis of polyethyleneimine based fluorescent polymeric nanorods using vitamin B6 cofactor as cross-linker for ratiometric detection of doxorubicin

Polyethyleneimine (PEI) based fluorescent polymeric nanorods with high quantum yield (87.21%) were synthesized by crosslinking and self-assembly of PEI by vitamin B6 cofactor pyridoxal 5'-phosphate (PLP). The fluorescent PEIPLP polymeric nanorods were employed for the ratiometric detection of doxorubicin (DOX). With the addition of DOX to the PEIPLP nanorods, the fluorescent intensity was decreased at 510 nm and concomitantly enhanced at 590 nm due to the fluorescence resonance energy transfer (FRET) process. The selective and specific ratiometric fluorescence response from the PEIPLP nanorods can be employed to detect DOX down to 10 nM. The practical utility of the PEIPLP nanorods was examined by detecting DOX in human serum.

Functionalizing of magnetic nanoparticles as nano-architecture towards bioimaging and colorimetric recognition of MCF-7 cells: dual opto-sensing and fluorescence monitoring for early-stage diagnosis of breast cancer

Considering the high incidence of breast cancer, a sensitive and specific approach is crucial for its early diagnosis and follow-up treatment. Folate receptors (FR), which are highly expressed on the epithelial tissue such as breast cancer cells (e.g., MCF-7), have been used in cancer diagnosis and bioimaging. This study presents an innovative colorimetric and fluorescence bioimaging platform towards MCF-7 using folic acid (FA)-conjugated iron-oxide magnetite silica-based nanocomposite (Fe3O4@SiO2-3-aminopropyl)triethoxysilane (APTES-NH2)@cysteine (Cyt)-Cyt@FA). For identification of MCF-7, the polyvinylpyrrolidone (PVP)-capped-platinum (Pt) nanoparticle was utilized as a nanozyme to catalyze the reaction between 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2 for visual detection of MCF-7 cells. Colorimetric changes are detectable by the naked eye and spectrophotometry at the wavelength of 450 nm, with a linear range of 50-5000 cells/mL and a detection limit of 30 cells/mL. The Fe3O4@SiO2-APTES-NH2@Cyt-Cyt@FA complex was modified with rhodamine B as a fluorescence bioimaging probe to monitor FR-overexpressed MCF-7 cells. The nanocomposite is biocompatible with a toxicity threshold of about 800 µg/mL. These methodologies facilitate bioimaging and colorimetric assays without sophisticated instrumentation, offering high specificity, sensitivity, repeatability, and stability, making them suitable as versatile methods for detecting and bioimaging cancer cells.

Quantum dots as a fluorescent labeling tool for live-cell imaging of Leptospira

Leptospirosis is a global public health problem caused by Gram-negative pathogenic bacteria belonging to the genus Leptospira. The disease is transmitted through the urine of infected animals, which contaminates water and soil, leading to the infection of other animals and humans. Currently, several approaches exist to detect these bacteria; however, a new sensitive method for the live-cell imaging of Leptospira is required. In this study, we report the green synthesis of cadmium telluride quantum dots (CdTe QDs) which are unique fluorescent nanocrystals with a high fluorescence quantum yield capable of modifying cell surfaces and are biocompatible with cells. The fabrication of QDs with concanavalin A (ConA), a carbohydrate-binding lectin and known biological probe for Gram-negative bacteria, produced ConA-QDs which can effectively bind on Leptospira and exhibit strong fluorescence under simple fluorescence microscopy, allowing the live-cell imaging of the bacteria. Overall, we performed the simple synthesis of ConA-QDs and demonstrated their potential use as versatile fluorescent probes for the live-cell imaging of Leptospira. This technique could be further applied to track leptospiral cells and study the infection mechanism, contributing to a more thorough understanding of leptospirosis and how to control it in the future.

Review of Advances in Coating and Functionalization of Gold Nanoparticles: From Theory to Biomedical Application

Nanoparticles, especially gold nanoparticles (Au NPs) have gained increasing interest in biomedical applications. Used for disease prevention, diagnosis and therapies, its significant advantages in therapeutic efficacy and safety have been the main target of interest. Its application in immune system prevention, stability in physiological environments and cell membranes, low toxicity and optimal bioperformances are critical to the success of engineered nanomaterials. Its unique optical properties are great attractors. Recently, several physical and chemical methods for coating these NPs have been widely used. Biomolecules such as DNA, RNA, peptides, antibodies, proteins, carbohydrates and biopolymers, among others, have been widely used in coatings of Au NPs for various biomedical applications, thus increasing their biocompatibility while maintaining their biological functions. This review mainly presents a general and representative view of the different types of coatings and Au NP functionalization using various biomolecules, strategies and functionalization mechanisms.

In-situ preparation of norepinephrine-functionalized silver nanoparticles and application for colorimetric detection of tacrolimus in plasma samples

Tacrolimus (Tac) is a well-documented immunosuppressive agent for the prevention of graft-vs-host diseases in several types of organ transplants. The narrow therapeutic window and the individual-variable pharmacokinetics of Tac demonstrate the importance of regular therapeutic drug monitoring (TDM) as an imperative concept for its oral medication regimens. A simple, one-step, selective, and sensitive colorimetric platform is fabricated for the determination of Tac by surface modification of the silver nanoparticles (AgNPs) via norepinephrine (NE) molecules. The attachment of NE and Tac induces the aggregation of the AgNPs, which is observed by color distinction (yellow to brown) and a noteworthy shifting of the absorption peak in the visible region. The fabricated nanoprobe can detect Tac concentrations in plasma samples in two linear ranges from 2 ng/mL to 70 ng/mL and 70 ng/mL to 1000 ng/mL with R2 > 0.99. The limit of detection (LOD) was calculated as low as 0.1 ng/mL. The developed method was applied for the determination of Tac in patient's plasma samples under Tac medication therapy.

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.