Protein carbonylation has been known as the major form of irreversible protein modifications and is also widely used as an indicator of oxidative stress in the biological environment. In the presence of oxidative stress, biological systems tend to produce large amounts of carbonyl moieties; these carbonyl groups do not have particular UV-Vis and fluorescence spectroscopic characteristics that we can differentiate, observe, and detect. Thus, their detection and quantification can only be performed using specific chemical probes. Commercially available fluorescent probes to detect specific carbonylation in biological systems have been used, but their chemical portfolio is still very limited. This protocol outlines the methods and procedures employed to synthesize a probe, (E,Z)-2-(2-(2-hydroxybenzylidene)hydrazonyl)-5-nitrophenol (2Hzin5NP), and assess its impact on carbonylation in human cells. The synthesis involves several steps, including the preparation of its hydrazone compounds mimicking cell carbonyls, 2-Hydrazinyl 5-nitrophenol, (E,Z)-2-(2-ethylidenehydrazonyl)-5-nitrophenol, and the final product (E,Z)-2-(2-(2-hydroxybenzylidene)hydrazonyl)-5-nitrophenol. The evaluation of fluorescence quantum yield and subsequent cell culture experiments are detailed for the investigation of 2Hzin5NP effects on cell proliferation and carbonylation.

The task of conveying scientific research to individuals with varying levels of knowledge and understanding can prove to be quite challenging for a research scientist. The difficulty is further compounded when the exchange of information must be conducted within a limited timeframe. Notwithstanding, the 'elevator pitch' is a valuable tool that enables researchers to navigate these potential obstacles. An effective elevator pitch not only facilitates the communication of a researcher's scientific findings but also highlights the individual's skills and the significance of their research. Moreover, a well-crafted elevator pitch is a critical career development tool, serving as a means of networking and paving the way for future communications, scientific collaborations, and funding opportunities. This article examines the value of a scientific elevator pitch and provides step-by-step guidelines for developing and constructing an impactful pitch. Furthermore, we provide resources and an example of a successful elevator pitch delivered by a Fellow from the NIH-funded Accelerating Career Transitions (ACT) program, a professional development program established and managed by the American Society for Cell Biology (ASCB).

Reactive aldehydes—formaldehyde (FA), malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), and acrolein—occupy a central role in epigenetic regulation, lipid peroxidation, ferroptosis, and cardiovascular disease, yet their transient nature and low intracellular concentrations have long made them difficult to quantify in living systems. Over the past decade, reaction-based small-molecule fluorescent probes have emerged as the principal tool for addressing this challenge, and this review provides a systematic account of that progress. We compare the six main conjugation chemistries that underlie current probe design—2-aza-Cope/Mannich cascade, hydrazone/oxime formation, Michael addition, Schiff base condensation, and 2-aminothiophenol cyclization—alongside the three photophysical strategies used to convert these reactions into quantitative signals: intensity turn-on, ratiometric dual-emission, and fluorescence lifetime imaging (FLIM). Attention is given to advances reported between 2020 and 2025, including organelle-targeted ratiometric formaldehyde sensors (MitoRFAP-2, NucRFAP-2), the first ratiometric acrolein probe for visualizing ferroptosis, lysosome-targeted malondialdehyde reporters for atherosclerosis staging, and near-infrared-compatible platforms validated in three-dimensional organoids and in vivo models. This review also critically examines the limitations that continue to constrain the field, including insufficient selectivity testing under physiologically relevant conditions, the pH-dependence of hydrazone equilibria, the frequently overlooked distinction between probes that report free aldehyde concentration and those that report ALDH enzyme activity, and the continued absence of reversible, real-time sensors. Closing these gaps will determine whether aldehyde imaging grows from a set of smart probes into a quantitative, widely trusted platform for studying redox and carbonyl biology in living systems. Reaching that point will depend on three criteria: better NIR fluorophores, effective bioconjugation chemistry, and machine-learning tools that guide probe design.

Reactive aldehydes—formaldehyde (FA), malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), and acrolein—occupy a central role in epigenetic regulation, lipid peroxidation, ferroptosis, and cardiovascular disease, yet their transient nature and low intracellular concentrations have long made them difficult to quantify in living systems. Over the past decade, reaction-based small-molecule fluorescent probes have emerged as the principal tool for addressing this challenge, and this review provides a systematic account of that progress. We compare the six conjugation chemistries that underlie current probe design—2-aza-Cope/Mannich cascade, hydrazone/oxime formation, Michael addition, Schiff base condensation, and 2-aminothiophenol cyclization—alongside the three photophysical strategies used to convert these reactions into quantitative signals: intensity turn-on, ratiometric dual-emission, and fluorescence lifetime imaging (FLIM). Attention is given to advances reported between 2020 and 2025, including organelle-targeted ratiometric formaldehyde sensors (MitoRFAP-2, NucRFAP-2), the first ratiometric acrolein probe for visualizing ferroptosis, lysosome-targeted malondialdehyde reporters for atherosclerosis staging, and near-infrared-compatible platforms validated in three-dimensional organoids and in vivo models. This review also critically examines the limitations that continue to constrain the field, including insufficient selectivity testing under physiologically relevant conditions, the pH-dependence of hydrazone equilibria, the frequently overlooked distinction between probes that report free aldehyde concentration and those that report ALDH enzyme activity, and the continued absence of reversible, real-time sensors. Closing these gaps will determine whether aldehyde imaging grows from a set of smart probes into a quantitative, widely trusted platform for studying redox and carbonyl biology in living systems. Reaching that point will depend on three criteria: better NIR fluorophores, effective bioconjugation chemistry, and machine-learning tools that guide probe design.