Probing Behavior Research Articles

A Highly Sensitive and Selective Quinazoline-Based Colorimetric Probe for Naked-Eye Detection of Fe3+ Ions.

A novel quinazoline-based colorimetric sensor (probe 1) that detected Fe3+ via naked-eye in a buffered MeOH: H2O (8:2) solvent system within a neutral pH range was synthesized and its structure was confirmed by 1H-NMR, 13C-NMR, FT-IR, and Mass spectroscopy. Its photophysical properties were also studied. The sensitivity and selectivity factor in the presence of 16 metal ions was examined by utilizing absorption titrations. Based on the selectivity test, probe 1 exhibited excellent selectivity and sensitivity toward Fe3+ ions among various other ions. The competitive effect indicated relatively low interference of other cations on the interaction of probe 1/Fe3+. To specify the sensing behavior of probe 1 to Fe 3+, the mole ratio method was carried out. After addition of around 500 µL of Fe3+, the absorption of probe1 reached saturation, and the reaction was completed. The effect of pH on the absorption and stability of probe 1 towards Fe3+ was examined. The pH range from 5.0 to 9.0 was appropriate for detection of Fe3+. To find the binding stoichiometric of the complex, Job's plot studies were carried out by varying the molar ratio of Fe3+. A 1:2 binding ratio was proposed. Under the optimal conditions, a good linear relationship (R2 = 0.9886) was at the concentration of Fe3+ over the range of 50-110µM, with a detection limit of 47.44nM. Our quinazoline-based probe has shown good results for the quantitative determination of Fe3+ in samples of urine with high recovery.

Turnip Mosaic Virus Infection Differentially Modifies Cabbage Aphid Probing Behavior in Spring and Winter Oilseed Rape (Brassica napus).

Simple SummaryWinter oilseed rape accounts for about 90% of total oilseed rape planting area in China, with the majority of it concentrated in the Yangtze River basin. The remaining 10% is mostly found in the provinces of China’s northwest plateau. Winter oilseed rape areas in China have gradually expanded to the north in the last decade, resulting in cabbage aphids and turnip mosaic virus (TuMV). The aphid is a vector for TuMV and is gradually increasing on winter and spring oilseed rape. Quantifying the probing behaviors of the aphids on spring oilseed rape and winter oilseed rape helps us to understand TuMV regulation of the aphids. We found that compared to mock-inoculated plants, cabbage aphids on infected plants increased brief probing frequency, cell penetration frequency, intracellular probing time, decreased time to first probe and pathway duration, potentially promoting viral acquisition and minimizing viral loss and plant damage. Viruliferous aphids had reduced pathway duration, increased cell penetration frequency, increased intracellular probing time, increased salivation frequency, and ingested less sap compared with non-viruliferous aphids, primed for viral infection. TuMV infection also differentially modified aphid feeding behavior on winter and spring oilseed rape cultivars, primarily on uninfected plants.Direct and indirect effects of plant virus infection on vector behavior have been discovered to improve virus transmission efficiency, but the impact of plant cultivars in virus–vector–plant interactions has received little attention. Electropenetrography (EPG) allows real-time tracking and quantification of stylet penetration behaviors, pathogen transmission, and plant resistance mechanisms. Quantitative probing behaviors on a spring oilseed rape cultivar, ‘Xinyou17’, and a winter oilseed rape cultivar, ‘Zheping4’, were investigated using EPG to compare turnip mosaic virus (TuMV) regulation of cabbage aphid probing behavior. Results for indirect effects showed that compared to mock-inoculated plants, cabbage aphids on infected plants increased brief probing frequency, cell penetration frequency, intracellular probing time, and decreased time to first probe and pathway time, potentially promoting viral acquisition. TuMV also directly influences aphid probing behavior. Viruliferous aphids had reduced pathway time, increased cell penetration frequency, increased intracellular probing time, increased salivation frequency, and ingested less sap than non-viruliferous aphids, primed for viral infection. Although oilseed rape cultivars can also influence aphid behavior, the main effect of cultivars was not significant on TuMV-infected plants.

Molecularly imprinted copolymer/reduced graphene oxide for the electrochemical detection of herbicide propachlor

The toxicity of propachlor (PROP) with its chloroacetanilide members is reported. Rapid and sensitive detection of PROP is critical for ecotoxicity evaluation and the removal process. A novel voltammetric sensor is developed based on imprinted poly (o-phenylene diamine-co-pyrrole) (o-PD-co-Py) and electrochemically reduced graphene oxide (ERGO) to detect PROP at a trace level. The use of ERGO provides a high density of imprinted cavities for better sensitivity. The imprinted layer of poly (o-PD-co-Py) improves the selectivity of the sensor. The electrode modification was characterized by scanning electron microscopy and electrochemical approaches. The working parameters of the sensor were investigated and optimized. The redox behavior of an external probe of [Fe(CN)6]3−/4− was recorded as the sensor signal for PROP selective binding. The proposed sensor presented wide linear responses to logarithmic PROP concentrations from 0.1 pM to 0.1 µM with a LOD of 0.08 pM. The sensor’s selectivity against some interference was demonstrated. This sensor was applied successfully to detect PROP in spiked water (lake and tap), red tea, and soil samples with good recoveries and reasonable RSD % values.Graphical abstract

Conjugated Polymer /Multi Wall Carbon Nanotubes Composite Characterisation for Application in Volatile Organic Compounds Sensors

Polyimidazole multi-walled carbon nanotubes (MWCNTs) nanocomposite film were synthesised by chemical oxidation of imidazole monomer and addition of MWCNTs to the conductive polymer (CP) solution in 1:1 ratio. Chemical characterisation using FTIR where there is an increased in intensity of peaks in the control sample from 2823 and 2937 cm-1 to 2833 and 2947 cm-1 in Plm/MWCNTs composite respectively and Raman spectroscopy in which Plm/MWCNTs shows the so-called D-band (attributed to disordered sp2 and non-sp2 carbon defects in graphitic sheets) and G-band (attributed to the C–C vibration with the sp2 hybridized orbital in graphene structures) peaks at 1355 cm-1 and 1593 cm-1, but chemical analysis confirmed the mixing of the polymer and the MWCNTs. Electrical measurements using current voltammetry (CV) that shows a reversible wave that is the typical behavior of conductive surfaces in the presence of the redox couple and Impedance measurements in which the largest semicircle was obtained with Plm/CNTs film that corresponds to a film resistance on the real axis of 350 MΩ which is an indication of a higher electron transfer rate in the redox probe and good electrical behaviour. The overall results have shown that the composite has a significant electrical conductivity and can be applied in sensing volatile organic compounds in the environment.

A dual-ratiometric mitochondria-targeted fluorescent probe to detect hydrazine in soil samples and biological imaging

Hydrazine (N2H4) is carcinogenic, extremely toxic, and induces serious environmental contamination and physiological dysfunction; however, it is widely used as an industrial material. Hence, the development of a simple and effective analytical method to detect N2H4 detection in both environmental and biological sectors is warranted. In this work, an intramolecular charge transfer (ICT)-based fluorescent probe 1, namely (Z)− 1-(4-acetoxybenzyl)− 4-(1-cyano-2-(7-(diethylamino)− 2-oxo-2 H-chromen-3-yl)vinyl)pyridin-1-ium, was designed for dual-excitation (420 and 600 nm, excitation separations >160 nm), near infrared (NIR)-emissive, and ratiometric fluorescent detection of N2H4. The sensing behavior of probe 1 for N2H4 detection was shown to be available over a wide pH range, and detection limits of 68 nM and 569 nM were achieved at excitation wavelengths of 420 and 600 nm, respectively. In addition, probe 1 was successfully used to image mitochondrial N2H4 in living cells and zebrafish. Furthermore, the probe was also capable of determining hydrazine signals in test strips and environmental soil.

Analysis of selective bonding processes using reactive multi-layers for system integration on LTCC based SiPs

This paper discusses the use of reactive multi-layers for selective assembly of ICs (Integrated Circuits) in an LTCC (Low Temperature Co-fired Ceramics) based SiP (System-in-Package). To understand the requirements for the use of self-propagating reactive multilayers in die bonding, CFD (Computational Fluid Dynamics) simulations have been carried out to simulate the die bonding process of a silicon chip onto a ceramic LTCC substrate. Reactive foils of 40 and 80 µm thicknesses and a simulated reaction propagation speed of 1 m/s were studied and used to melt a solder preform underneath a silicon chip. The results of the CFD simulations were analysed, particularly with respect to temperature and liquid fraction contours, as well as time–temperature histories obtained from temperature probes which were included in the model, such as to approximate the real behaviour of Pt-100 temperature probes, when a real bonding process is being tracked. The CFD method, in this instance realised with ANSYS Fluent software, can track the melting and solidification of the solder as well as model the influence of latent heat, which is crucial to ascertaining the true evolution of the bonding process.

Fabrication of Two Isomorphic and Hyperstable Rare Earth-Based Metal–Organic Frameworks with Efficient Ratiometric Probe and Photocatalytic Performances

Two isomorphic lanthanide compounds {[Ln(ddpp)(H2O)]·CH3CN}n (Ln = Eu and Gd, H4ddpp = 2,5-di(2',4'-dicarboxylphenyl)pyridine) were synthesized. Complex 1-Eu displays ultrahigh acid-base stability and thermal stability. Furthermore, luminescence measurements revealed that 1-Eu could detect quinolone antibiotics with an ultralow limit of detection in aqueous solution. The ratiometric probe properties for sensing antibiotics could be attributed to the incompletely sensitized Eu3+ ion of the ligand. Remarkably, it is interesting that 1-Gd exhibits excellent tetracycline degradation properties under visible light. Ultraviolet-visible diffuse reflectance spectroscopy and valence band X-ray photoelectron spectroscopy were carried out to investigate the photodegradation mechanisms. Moreover, a rational explanation for the fluorescent probe and photocatalysis behavior of these two complexes was also discussed with the assistance of density functional theory calculations.

Belowground Herbivory to Sweetpotato by Sweetpotato Weevil (Coleoptera: Brentidae) Alters Population Dynamics and Probing Behavior of Aboveground Herbivores.

Aboveground and belowground herbivory can alter host quality and trophic interactions. However, little research has explored the impacts of belowground herbivory on plant virus epidemiology. To understand this interaction in sweetpotato, Ipomoea batatas L. (Lam), we studied the impact of herbivory by sweetpotato weevil, Cylas formicarius elegantulus (Summers), to storage roots on vector herbivore, Myzus persicae (Sulzer), the green peach aphid, and Aphis gossypii Glover, the cotton aphid, feeding behavior (M. persicae and A. gossypii) and population dynamics (M. persicae only as A. gossypii does not colonize sweetpotato). In addition, a nonvector herbivore, Chrysodeixis includens (Walker), the soybean looper, weight gain was included for comparison. Infestations of sweetpotato weevil in storage roots reduced C. includens weight gain and M. persicae intrinsic rate of increase (rm), net reproductive rate (Ro), and finite rate of increase (λ) on aboveground portions of the plant. In probing behaviors related to nonpersistent virus spread (30 min trials), M. persicae probed less often, took longer to reach the first pd (potential drop), had shorter II-3 (intracellular subphase sap ingestion) durations, and had fewer archlets on plants infested with C. formicarius elegantulus. Total phloem duration did not differ between treatments, indicating that the lowered performance of M. persicae on infested plants was not due to discrepancies in probing duration. Results were less clear for A. gossypii. Thus, in sweetpotato, belowground herbivory can alter plant virus vector abundance and behavior. Understanding the mechanisms underlying these changes in behavior could improve plant virus vector integrated pest management.

A Computational Probe into the Behavioral and Neural Markers of Atypical Facial Emotion Processing in Autism.

Despite ample behavioral evidence of atypical facial emotion processing in individuals with autism spectrum disorder (ASD), the neural underpinnings of such behavioral heterogeneities remain unclear. Here, I have used brain-tissue mapped artificial neural network (ANN) models of primate vision to probe candidate neural and behavior markers of atypical facial emotion recognition in ASD at an image-by-image level. Interestingly, the image-level behavioral patterns of the ANNs better matched the neurotypical subjects 'behavior than those measured in ASD. This behavioral mismatch was most remarkable when the ANN behavior was decoded from units that correspond to the primate inferior temporal (IT) cortex. ANN-IT responses also explained a significant fraction of the image-level behavioral predictivity associated with neural activity in the human amygdala (from epileptic patients without ASD), strongly suggesting that the previously reported facial emotion intensity encodes in the human amygdala could be primarily driven by projections from the IT cortex. In sum, these results identify primate IT activity as a candidate neural marker and demonstrate how ANN models of vision can be used to generate neural circuit-level hypotheses and guide future human and nonhuman primate studies in autism.SIGNIFICANCE STATEMENT Moving beyond standard parametric approaches that predict behavior with high-level categorical descriptors of a stimulus (e.g., level of happiness/fear in a face image), in this study, I demonstrate how an image-level probe, using current deep-learning-based ANN models, allows identification of more diagnostic stimuli for autism spectrum disorder enabling the design of more powerful experiments. This study predicts that IT cortex activity is a key candidate neural marker of atypical facial emotion processing in people with ASD. Importantly, the results strongly suggest that ASD-related atypical facial emotion intensity encodes in the human amygdala could be primarily driven by projections from the IT cortex.

Effects of Acibenzolar-S-methyl on the Probing Behaviour and Mortality of Cacopsylla pyri on Pear Plants.

European pear psylla, Cacopsylla pyri, is one of the worst pests of pear in Europe. We investigated whether acibenzolar-S-methyl (ASM) application on pear plants might affect the behaviour in C. pyri. The elicitor was applied on pear potted plants, and after 48 h, we confirmed the ASM-mediated induction of several Pathogenesis-Related protein (PR) coding genes. At the same time, an in-depth analysis was performed on the probing behaviour of adults and nymphs of C. pyri on ASM-treated pear plants by the EPG-DC system, as well as the assessment of young nymphs' survival 7 days after the ASM application. The elicitor application weakly interfered with C. pyri nymphs probing behaviour and survival, while it did not affect adult stages. These data confirm previous observations obtained on C. pyricola and suggest that the elicitor does not represent a viable tool in the control of pear psylla species, especially if used alone, but it might be used in integrated management strategies focused on other plant pathogens such as Erwinia amylovora.

Probing behavior of the corn leafhopper Dalbulus maidis on susceptible and resistant maize hybrids.

The corn leafhopper Dalbulus maidis is the main vector of the pathogens that cause corn stunt, a major disease of maize in the Americas. In line with plant resistance being an efficient tool to control diseases, the findings of a previous work showed that some corn hybrids are resistant to D. maidis. In this work, we assessed the probing behavior of D. maidis on susceptible and resistant corn hybrids using EPG (Electrical Penetration Graph) technology. Feeding of fifteen-day-old, non-inoculative females was recorded for 20 hours, with access to hybrids DK390, DK670, DK79-10, and DK72-10. Compared to the susceptible hybrid DK670, the other hybrids shifted D. maidis probing behavior in a way consistent with plant resistance to insects. This shift consisted of a higher number of probes of short duration, difficulties in attaining phloem ingestion and increase in xylem ingestion. In addition to this common shift in probing behavior, a phloem-located resistance factor was inferred in DK72-10 based on the longer time spent in phloem conditioning to attain phloem ingestion. In contrast, DK390 expressed the highest level of mesophyll and phloem-based resistance, in both cases seen with repeated attempts of short duration, a behavior typically associated with failed attempts to ingest. These findings support and are consistent with previous research, providing useful information to characterize maize hybrids resistant to D. maidis, and consequently to corn stunt.

Insect vector manipulation by a plant virus and simulation modeling of its potential impact on crop infection

There is widespread evidence of plant viruses manipulating behavior of their insect vectors as a strategy to maximize infection of plants. Often, plant viruses and their insect vectors have multiple potential host plant species, and these may not overlap entirely. Moreover, insect vectors may not prefer plant species to which plant viruses are well-adapted. In such cases, can plant viruses manipulate their insect vectors to preferentially feed and oviposit on plant species, which are suitable for viral propagation but less suitable for themselves? To address this question, we conducted dual- and no-choice feeding studies (number and duration of probing events) and oviposition studies with non-viruliferous and viruliferous [carrying beet curly top virus (BCTV)] beet leafhoppers [Circulifer tenellus (Baker)] on three plant species: barley (Hordeum vulgare L.), ribwort plantain (Plantago lanceolata L.), and tomato (Solanum lycopersicum L.). Barley is not a host of BCTV, whereas ribwort plantain and tomato are susceptible to BCTV infection and develop a symptomless infection and severe curly top symptoms, respectively. Ribwort plantain plants can be used to maintain beet leafhopper colonies for multiple generations (suitable), whereas tomato plants cannot be used to maintain beet leafhopper colonies (unsuitable). Based on dual- and no-choice experiments, we demonstrated that BCTV appears to manipulate probing preference and behavior by beet leafhoppers, whereas there was no significant difference in oviposition preference. Simulation modeling predicted that BCTV infection rates would to be higher in tomato fields with barley compared with ribwort plantain as a trap crop. Simulation model results supported the hypothesis that manipulation of probing preference and behavior may increase BCTV infection in tomato fields. Results presented were based on the BCTV-beet leafhopper pathosystem, but the approach taken (combination of experimental studies with complementary simulation modeling) is widely applicable and relevant to other insect-vectored plant pathogen systems involving multiple plant species.

Entomopathogenic fungus disrupts the phloem-probing behavior of Diaphorina citri and may be an important biological control tool in citrus

Citrus is among the most important fruit crops worldwide; however, numerous pests and diseases affect the orchards, increasing production costs. The psyllid Diaphorina citri, is a vector of the phloem-limited bacteria ‘Candidatus Liberibacter spp.’, the causal agent of Huanglongbing (HLB) disease. The lack of a cure for HLB requires management of the vector, mainly by intensive use of chemical insecticides, leading to the selection of resistant populations. Our study determined the effects of the entomopathogenic fungus Cordyceps fumosorosea on the probing behavior of D. citri at different time points after the fungus was applied by spraying. The electrical penetration graph technique was used to monitor the stylet activities of D. citri after application of the microbiological product. The effects were more pronounced between 30 and 96 h after the insects were sprayed, with significant disruption of the stylet activities related to the phloem and directly associated with the transmission of HLB. Our study indicated that the microbiological product Challenger®, with the active ingredient C. fumosorosea fungus, can significantly change the probing behavior of D. citri, may be helpful in more-sustainable management of the vector, and can be used to reduce the spread of HLB.

Visualization of Macrophase Separation and Transformation in Immiscible Polymer Blends

Visualization of Macrophase Separation and Transformation in Immiscible Polymer Blends

Applicability of Selected 3D Printing Materials in Electrochemistry.

This manuscript investigates the chemical and structural stability of 3D printing materials (3DPMs) frequently used in electrochemistry. Four 3D printing materials were studied: Clear photopolymer, Elastic photopolymer, PET filament, and PLA filament. Their stability, solubility, structural changes, flexibility, hardness, and color changes were investigated after exposure to selected organic solvents and supporting electrolytes. Furthermore, the available potential windows and behavior of redox probes in selected supporting electrolytes were investigated before and after the exposure of the 3D-printed objects to the electrolytes at various working electrodes. Possible electrochemically active interferences with an origin from the 3DPMs were also monitored to provide a comprehensive outline for the use of 3DPMs in electrochemical platform manufacturing.

Structural, shear and volume relaxation in a commercial float glass during aging

Density, Raman spectroscopy and viscosity measurements are utilized to probe, respectively, the volume, structural and shear relaxation behavior of a Na-Ca-Mg silicate glass of standard commercial float composition at ∼80 °C below its calorimetric glass transition. The results, when taken together, indicate that the lowering of fictive temperature of the glass during aging results in a Q-species disproportionation of the type Q2+Q4→2Q3, and all three relaxation processes are characterized by stretched exponential kinetics with similar average timescale (〈τ〉∼ 300 h) and stretching exponent (β ∼ 0.4), implying a close mechanistic relationship. It is hypothesized that the coexistence of strongly and weakly constrained domains or structural moieties in the network of a glass or supercooled liquid can give rise to a temporal decoupling between the structural and shear relaxation processes, as has been reported in some of the recent studies in the literature.

A new mitochondrial probe combining pyrene and a triphenylphosphonium salt for cellular oxygen and free radical detection via fluorescence lifetime measurements

To improve and diversify the quantification of reactive oxygen species (ROS) in mitochondria of single cells, we connected pyrene derivatives (PB) to a triphenylphosphonium salt (TPP+) as a mitochondrial vector forming PB-TPP+ probes. Two pyrene isomers with the n-butyltriphenylphosphonium moieties attached at their 1- or 2- positions were synthesized and characterized. Using the long fluorescence lifetime of pyrene, it was possible to monitor the variation of cellular free radicals and oxygen and to follow the reversibility of both quenchers in real-time. We compared the behavior of these new probes to the previously published pyrene-probes, functionalized by a mitochondrial-penetrating peptide, allowing their transfer to the mitochondria (Mito-PB) or to the cytosolic membrane for pyrene butyric acid (PBA). The high cellular uptake of the new probes allows cells to be loaded with an initial concentration 40 times lower than that for Mito-PB probes, without inducing perturbations in cell growth. The variation in free radicals and oxygen levels was monitored within cells under different stress conditions through the fluorescence lifetime of the new TPP+-based probes giving comparable results to those obtained for MPP-based probes. However, at a loading concentration as low as 25 nM, our technique allows the detection of increased production of free radicals in the mitochondria in the presence of the TPP+ vector, a warning to the user of this well-known vector.

Dysprosium(III) Metal–Organic Framework Demonstrating Ratiometric Luminescent Detection of pH, Magnetism, and Proton Conduction

A multifunctional metal-organic framework, (Hdmbpy)[Dy(H2dobdc)2(H2O)]·3H2O (Dy-MOF, H4dobdc = 2,5-dihydroxyterephthalic acid, dmbpy = 4,4'-dimethyl-2,2'-bipyridine), was synthesized and structurally characterized. The metal center DyIII is connected by four carboxyl groups to form the [Dy2(CO2)4] binuclear nodes, which are further interconnected by eight separate H2dobdc2- ligands to form a three-dimensional (3D) framework including hydrophilic triangular channels and abundant hydrogen-bonding networks. Dy-MOF has good stability in aqueous solution as well as in harsh acidic or alkaline solutions (pH range: 2.0-12.0). Furthermore, the luminescence signal of Dy-MOF undergoes a visualized color change as the acidity of the solution alters, which is the typical behavior of pH ratiometric probe. At a 100% relative humidity, Dy-MOF exhibits a high proton conductivity σ (1.70 × 10-4 S cm-1 at 303 K; 1.20 × 10-3 S cm-1 at 343 K) based on the proton hopping mechanism, which can be classified as a superionic conductor with σ exceeding 10-4 S cm-1. Additionally, the ferromagnetic interaction and magnetic relaxation behavior are simultaneously achieved in Dy-MOF. Herein, the combination of luminescence sensing, magnetism, and proton conduction in a single-phase 3D MOF may offer great potential applications in smart multitasking devices.

Fluid dynamic simulations at the interface of the blue-green sharpshooter functional foregut and grapevine xylem sap with implications for transmission of Xylella fastidiosa.

Xylella fastidiosa is a multi-continental, lethal, plant pathogenic bacterium that is transmitted by sharpshooter leafhoppers (Insecta: Hemiptera: Cicadellidae: Cicadellinae) and adult spittlebugs (Hemiptera: Aphrophoridae). The bacterium forms biofilms in plant xylem and the functional foregut of the insect. These biofilms serve as sources of inoculum for insect acquisition and subsequent inoculation to a healthy plant. In this study, 3D fluid dynamic simulations were performed for bidirectional cibarial propulsion of xylem sap through tube-like grapevine xylem and an anatomically accurate model of the functional foregut of the blue-green sharpshooter, Graphocephala atropunctata. The analysis supports a model of how fluid dynamics influence X. fastidiosa transmission. The model supports the hypothesis that X. fastidiosa inoculation is mostly driven by detachment of bacteria from the foregut due to high-velocity flow during egestion (outward fluid flow from the stylets). Acquisition occurs by fluid dynamics during both egestion and ingestion (fluid uptake through the stylets and swallowing). These simulation results are supported by previously reported X. fastidiosa colonization patterns in the functional foregut and sharpshooter stylet probing behaviors. The model indicates that xylem vessel diameter influences drag forces imposed on xylem wall-adherent bacteria; thus, vessel diameter may be an important component of the complex transmission process. Results from this study are directly applicable to development of novel grapevine resistance traits via electropenetrographic monitoring of vector acquisition and inoculation behaviors.

PH-responsive aldehyde-bearing cyclometalated iridium(III) complex for tracking intracellular pH fluctuations under external stimulation

Intracellular pH undertakes critical functions in various biological and pathological processes. It is important to monitor intracellular pH fluctuations for understanding physiological and pathological processes. Here, one aldehyde-bearing cyclometalated iridium(III) complex ([(4-pba)2Ir(dcphen)]PF6, 4-pba = 4-(2-pyridyl) benzaldehyde, dcphen = 4,7-dichloro-1,10-phenanthroline, probe 1) was synthesized and used to track intracellular pH fluctuations. Probe 1 displayed pH-dependent luminescence property in pH range of 1.81–6.81 with an evaluated pKa value of 4.30 in BR buffer-DMSO (v:v = 99:1). An intramolecular hydrogen bonds assisted pH-responsive mechanism was proposed for the pH-responsive behavior of probe 1. Probe 1 was successfully applied for imaging and tracking pH fluctuations in HeLa cells under external stimulation with fast response time, good photostability as well as low cytotoxicity and high cell permeability. This work demonstrates that aldehyde-bearing cyclometalated iridium(III) complex can be used as alternative pH-responsive probe for real-time tracking intracellular pH fluctuations, which provides a strategy for the design of pH-responsive probe in versatile applications.