Toward Point-of-Care Detection of Mycobacterium tuberculosis: A Brighter Solvatochromic Probe Detects Mycobacteria within Minutes

Abstract

There is an urgent need for point-of-care tuberculosis (TB) diagnostic methods that are fast, inexpensive, and operationally simple. Here, we report on a bright solvatochromic dye trehalose conjugate that specifically detects Mycobacterium tuberculosis (Mtb) in minutes. 3-Hydroxychromone (3HC) dyes, known for having high fluorescence quantum yields, exhibit shifts in fluorescence intensity in response to changes in environmental polarity. We synthesized two analogs of 3HC-trehalose conjugates (3HC-2-Tre and 3HC-3-Tre) and determined that 3HC-3-Tre has exceptionally favorable properties for Mtb detection. 3HC-3-Tre-labeled mycobacterial cells displayed a 10-fold increase in fluorescence intensity compared to our previous reports on the dye 4,4- N,N -dimethylaminonapthalimide (DMN-Tre). Excitingly, we detected fluorescent Mtb cells within 10 min of probe treatment. Thus, 3HC-3-Tre permits rapid visualization of mycobacteria that ultimately could empower improved Mtb detection at the point-of-care in low-resource settings.

Chemical Reporters for Bacterial Glycans: Development and Applications

“…266 Since its initial disclosure in 2018, DMN-Tre has also been applied to develop highcontent screening of potential inhibitors against intracellular M. tuberculosis, 303 tested for detection of M. tuberculosis in patient bioaerosols, 304 and adapted into next-generation, brighter solvatochromic trehalose probes. 305 Fluorescent trehalose probes such as 93−98 offer the convenience of one-step incorporation but have low versatility because their chemical tag is predetermined and they are limited to fluorescence detection applications. Furthermore, the large fluorophore may restrict the route or efficiency of metabolic incorporation.…”

“…DMN-Tre was then translated to the successful detection of viable M. tuberculosis in sputum samples from patients with tuberculosis, showing its potential as a diagnostic reagent . Since its initial disclosure in 2018, DMN-Tre has also been applied to develop high-content screening of potential inhibitors against intracellular M. tuberculosis , tested for detection of M. tuberculosis in patient bioaerosols, and adapted into next-generation, brighter solvatochromic trehalose probes …”

Exploiting the Twisted Intramolecular Charge Transfer Effect to Construct a Wash-Free Solvatochromic Fluorescent Lipid Droplet Probe for Fatty Liver Disease Diagnosis

“…Generally, donor–acceptor-structured fluorescent probes exhibit a prominent solvatochromic effect, leading to sensitive fluorescence alterations toward environmental polarity changes. , Lipid droplets are inherently low-polarity organelles − owing to the high components of triglycerides and cholesterol esters. − Considering the low-polarity environment of lipid droplets and the theory of similarity and intermiscibility, we believed that lipophilic fluorescent probes with a strong twisted intramolecular charge transfer (TICT) effect could achieve high-contrast lipid droplet imaging . As part of our continuous contribution to the lipid droplet-related field, − here we synthesized a novel solvatochromic probe (named ANI) based on naphthalene as a donor group and 1,3-indandione as an acceptor group (Scheme ).…”

AuCl3-Catalyzed Hemiacetal Activation for the Stereoselective Synthesis of 2-Deoxy Trehalose Derivatives

“… 2 , 7 , 8 Targeting trehalose uptake and subsequent metabolism has garnered attention in recent years as an attractive route for the development of novel therapeutics and diagnostic agents. 9 − 14 Previous elegant studies reported the synthesis of a series of symmetrical and unsymmetrical trehalose mimetics, including amino, azido, fluoro, iodo, 2-deoxy, and phosphate functionalities, as well as a fluorescein-functionalized analogue that was shown to label Mtb . 10 Subsequently, a range of differently functionalized trehalose analogues with fluorescent dyes 12 , 15 , 16 and biorthogonal handles, 17 including azides, 18 , 19 alkynes, 11 , 20 and photoactivatable diazirines, 21 have been shown to be metabolically incorporated into the mycomembrane of live mycobacteria.…”

“…Trehalose monomycolate (TMM) and dimycolate (TDM), bearing one and two 6- O- mycolyl substituents, respectively, are produced in all mycobacterial species and have been shown to be crucial components of the outer layer of the cell wall of Mycobacterium tuberculosis ( Mtb ). These glycolipids play essential roles in Mtb cell wall biosynthesis and in the viability and virulence of the pathogen. ,, Targeting trehalose uptake and subsequent metabolism has garnered attention in recent years as an attractive route for the development of novel therapeutics and diagnostic agents. − Previous elegant studies reported the synthesis of a series of symmetrical and unsymmetrical trehalose mimetics, including amino, azido, fluoro, iodo, 2-deoxy, and phosphate functionalities, as well as a fluorescein-functionalized analogue that was shown to label Mtb . Subsequently, a range of differently functionalized trehalose analogues with fluorescent dyes ,, and biorthogonal handles, including azides, , alkynes, , and photoactivatable diazirines, have been shown to be metabolically incorporated into the mycomembrane of live mycobacteria.…”