Function Of Formaldehyde Research Articles

An activatable formaldehyde donor with high contrast bioluminescence to monitor its release

High signal-to-background ratio (SBR) monitoring of formaldehyde (FA) delivery in living systems is of great significance for the precise study of the physiological and pathological functions of FA. However, traditional FA donors mainly use fluorescent signals to monitor FA release, which hampers the high-performance bioimaging due to the undesirable background autofluorescence, leading to poor SBR and compromised imaging sensitivity. Herein, we present the first bioluminogenic donor B-FAD for esterase-activated FA release with high contrast bioluminescence imaging. By protecting the hydroxyl group of D-luciferin with acetoxymethyl ether group, B-FAD cannot be catalyzed by luciferase to emit light. In the presence of esterase, the ester bond of B-FAD breaks, producing FA and D-luciferin. B-FAD selectively and sensitively releases FA in the presence of esterase, accompanied by 34-fold bioluminescence enhancement. In addition, B-FAD has been successfully applied for FA delivery and bioluminescence imaging in living cells, with a SBR about 50 times higher than those obtained by fluorescence imaging. Therefore, in addition to providing an effective tool for imaging FA delivery in living cells, this work establishes a general approach for high contrast monitoring other reactive biological species release by easily changing the responsive unit on D-luciferin.

Unveiling the negative correlation of formaldehyde and hydrogen sulfide in Parkinson’s disease models using a dual-responsive ruthenium(II) complex probe

Parkinson’s disease (PD) is one of the most common neurodegenerative diseases caused by various complicated pathological processes. Recent studies have revealed that formaldehyde (FA) and hydrogen sulfide (H2S) are essential signal molecules closely linked to central nervous systems. Therefore, understanding the physiological functions and relationship of FA and H2S in PD is beneficial for the early diagnosis and treatment of PD. However, an effective tool that could detect and visualize FA and H2S simultaneously in PD is still lacking. Herein we report the design and synthesis of a novel dual-responsive ruthenium(II) complex-based luminescent probe, Ru-aza-NBD, for the discriminatory detection of FA and H2S in aqueous media and PD models of living cells and mouse brains. Notably, using Ru-aza-NBD as a probe, the increased level of FA and the decreased level of H2S in PD models were discovered, which revealed the negative correlation of FA and H2S in PD for the first time. Collectively, Ru-aza-NBD could be an excellent tool for further investigating the biological functions of FA and H2S in pathological processes of PD, which offers a promising approach for the exploration of the pathogenic mechanism, diagnosis and treatment of this disease.

A robust activatable two-photon fluorescent probe for endogenous formaldehyde biomarker visualization diagnosis and evaluation of diabetes mellitus

Diabetes mellitus and its complications are one of the largest healthcare burdens in the world and are increasing every year. However, the lack of effective biomarkers and non-invasive real-time monitoring tools remains a great challenge for the early diagnosis of diabetes mellitus. Endogenous formaldehyde (FA) represents a key reactive carbonyl species in biological systems, and altered metabolism and functions of FA have been closely related to the pathogenesis and maintenance of diabetes. Among various noninvasive biomedical imaging techniques, the identification-responsive fluorescence (FL) imaging could greatly benefit the comprehensive multi-scale assessment of some diseases such as diabetes. Herein, we have designed a robust activatable two-photon probe DM-FA for the first highly selective monitoring of fluctuations in FA levels during diabetes mellitus. Through the density functional theory (DFT) theoretical calculations, we elucidated the rationality of the activatable fluorescent probe DM-FA turning on the FL before and after the reaction with FA. In addition, DM-FA has excellent high selectivity, high growth factor and good photostability in the process of recognizing FA. Due to the brilliant two-photon and one-photon FL imaging capabilities of DM-FA, it has been successfully used to visualize of exogenous and endogenous FA in cells and mice. Remarkably, as a powerful FL imaging visualization tool, DM-FA was introduced for the first time to visually diagnose and explore diabetes through the fluctuation of FA content. The successful application of DM-FA in two-photon and one-photon FL imaging experiments found elevated FA levels in high glucose-stimulated diabetic cell models. We successfully visualized upregulation of FA levels in diabetic mice and decreased of FA levels in diabetic mice scavenged by NaHSO3 from multiple perspectives using multiple imaging modalities. This work may provide a novel strategy for the initial diagnosis of diabetes mellitus and the evaluation of the efficacy of drug therapy for treating diabetes mellitus, which will likely have a positive impact on clinical medicine.

Cell-permeable fluorescent indicator for imaging formaldehyde activity in living systems

Formaldehyde (FA), as a reactive signaling molecule, plays an important role in living systems through a diverse array of cellular pathways. However, no systematic investigation for detection and imaging of FA by rendering cells transiently permeable has been reported yet. Specifically, we developed a new cell-permeable fluorescence probe functionality that was enhanced cellular entry efficiency and well retained intracellularly after activation for visualizing endogenous FA changes. Moreover, a smart “multi-lock system -key-and-lock” strategy，which have provoked a starting point for the use of probe and related biochemical tools to monitor FA in lysosomes. The versatile “latent” fluorophore that can undergo a subsequent self-immolative spacer for interrogating the roles and functions of FA in living systems as well as related biomedical applications.

A novel fluorescent probe for ratiometric detection of formaldehyde in real food samples, living tissues and zebrafish.

Herein, a two-photon (TP) ratiometric fluorescent probe (NpFA) was developed for detecting formaldehyde (FA) in real food samples, living onion tissues and zebrafish by fluorescence resonance energy transfer (FRET) strategy. Specifically, a TP fluorophore as the donor and a FA turn-on naphthalimide fluorophore as the acceptor were connected by a non-conjugated linker to construct the TP-FRET-based NpFA, which exhibited a target-modulated ratiometric fluorescence response to FA rapidly with high selectivity and sensitivity during 65s, and a large ratio ~5-fold enhancement at I550/I410 after addition of FA, displaying ~60-fold enhancement at 550nm and a quite low DOC of 5.8±0.2nM. Moreover, NpFA has a good imaging resolution and depth of deep tissue penetration. Therefore, based on the above results, NpFA has the capability to be a useful tool for investigating FA in real samples application, and we also hope NpFA will further study of the physiological and pathological function of FA.

Recent advances in formaldehyde-responsive fluorescent probes

Formaldehyde, as one of the simplest reactive carbonyl species (RCS), is regarded as a potential carcinogen and a sick house syndrome gas. Recent studies have shown that abnormally high levels of formaldehyde may result in cognitive decline and spatial memory deficits, asthmatic symptoms, Alzheimer’s disease, and cancer. Due to the harmfulness of high levels of formaldehyde in nature and humans, it is of great significance to further elucidate the roles and functions of formaldehyde by a non-invasive detection approach. Fluorescence imaging has become a powerful and popular tool in monitoring bio-species owing to their high sensitivity and selectivity, excellent spatiotemporal resolution and non-invasion nature. Therefore, fluorescent probes are widely applied to track and detect formaldehyde in vitro and in vivo which have attracted more and more interest recently. This review focuses on various strategies to design the fluorescent probes for detecting formaldehyde based on different recognition groups.

Pacific whiting frozen fillets as affected by postharvest processing and storage conditions

Whole fish and H&G (headed and gutted) fish were stored under refrigeration (<4°C) for 0, 2, and 5days and subsequently filleted and frozen at −18°C and −80°C. Frozen fillets were analyzed during 24weeks of storage. The activity of trimethylamine-N-oxide demethylase (TMAOase) decreased more quickly at −18°C than −80°C. TMAOase reduction was distinctively noted at −18°C storage. Formaldehyde (FA) induced by TMAOase increased at all treatments at −18°C as frozen storage extended to 24weeks, but it was near zero at −80°C up to 12weeks of storage. Textural toughening, low water retention ability, and low salt soluble protein resulted from the denaturation function of FA. A sudden decrease in surface hydrophobicity at 24weeks, when stored at −18°C, resulted from FA-induced unfolding and subsequent aggregation. FA concentration appeared to affect protein aggregations and textual toughening of fillets during frozen storage.