Electrochemical Nanoaptasensor for Continuous Monitoring of ATP Fluctuation at Subcellular Level

Electroactive polymer tag modified nanosensors for enhanced intracellular ATP detection

ATP plays a crucial role in cell energy supply, so the quantification of intracellular ATP levels is particularly important for understanding many physio-pathological processes. The intracellular quantification of this non-electroactive molecule can be realized using aptamer-modified nanoelectrodes, but is hindered by the limited quantity of modification and electroactive tags on the nanosized electrodes. Herein, we developed a simple but effective electrochemical signal amplification strategy for intracellular ATP detection, which replaces the regular ATP aptamer-linked ferrocene monomer with a polymer, thus greatly magnifying the amounts of electrochemical reporters linked to one chain of the aptamer and enhancing the signals. This ferrocene polymer-ATP aptamer was further immobilized onto Au nanowire electrodes (SiC@C@Au NWEs) to achieve accurate quantification of intracellular ATP in single cells, presenting high electrochemical signal output and high specificity. This work not only provides a powerful tool for quantifying intracellular ATP but also offers a simple and versatile strategy for electrochemical signal amplification in the detection of broader non-electroactive molecules involved in different kinds of intracellular physiological processes.

Pyridine appended pyrimidine bis hydrazone: Zn2+/ATP detection, bioimaging and functional properties of its dinuclear Zn(II) complex

A pyridine functionalized pyrimidine-based system, H2P was successfully synthesized, characterized, and evaluated for its remarkable selective characteristics towards Zn2+ and ATP ions. The chemical sensing capabilities of H2P were demonstrated through absorption, fluorescence, and NMR spectroscopic techniques. The probe exhibited outstanding sensitivity when interacting with the ions, demonstrating relatively strong association constants and impressively low detection limits. The comprehensive binding mechanism of H2P with respect to Zn2+ and ATP ions was investigated using a combination of analytical methods, including Job's plot, NMR spectroscopy, mass spectrometry, and density functional theory (DFT) experiments. The interesting sensing ability of H2P for Zn2+/ATP ions was harnessed for live cell bioimaging and other diverse on-site detection purposes, including paper strips, cotton swabs, and applications involving mung bean sprouts. Further, the fluorescent probe demonstrated its effectiveness in detecting Zn2+ and ATP within live cells, indicating its significant potential in the realm of biological imaging applications. Moreover, the molecular configuration of the zinc complex (H2P-Zn2Cl4), derived from H2P, was elucidated using X-ray crystallography. This complex exhibited intriguing multifunctional attributes, encompassing its capability for detecting picric acid and for reversible acid/base sensing responses. The enhanced conducting behavior of the complex as well as its resistance properties were investigated by performing I-V characteristics and electrochemical impedance spectroscopic (EIS) experiments respectively.

An Uncommon Phosphorylation Mode Regulates the Activity and Protein Interactions of N-Acetylglucosamine Kinase

While the function of protein phosphorylation in eukaryotic cell signaling is well established, the role of a closely related modification, protein pyrophosphorylation, is just starting to surface. A recent study has identified several targets of endogenous protein pyrophosphorylation in mammalian cell lines, including N-acetylglucosamine kinase (NAGK). Here, a detailed functional analysis of NAGK phosphorylation and pyrophosphorylation on serine 76 (S76) has been conducted. This analysis was enabled by using amber codon suppression to obtain phosphorylated pS76-NAGK, which was subsequently converted to site-specifically pyrophosphorylated NAGK (ppS76-NAGK) with a phosphorimidazolide reagent. A significant reduction in GlcNAc kinase activity was observed upon phosphorylation and near-complete inactivation upon pyrophosphorylation. The formation of ppS76-NAGK proceeded via an ATP-dependent autocatalytic process, and once formed, ppS76-NAGK displayed notable stability toward dephosphorylation in mammalian cell lysates. Proteomic examination unveiled a distinct set of protein-protein interactions for ppS76-NAGK, suggesting an alternative function, independent of its kinase activity. Overall, a significant regulatory role of pyrophosphorylation on NAGK activity was uncovered, providing a strong incentive to investigate the influence of this unusual phosphorylation mode on other kinases.

Realizing Ultrasensitive and Accurate Point-of-Care Profiling for ATP with a Triple-Mode Strategy Based on the ATP-Induced Reassembly of a Copper Coordination Polymer Nanoflower

New strategies for accurate and reliable detection of adenosine triphosphate (ATP) with portable devices are significant for biochemical analysis, while most recently reported approaches cannot satisfy the detection accuracy and independent of large instruments simultaneously, which are unsuitable for fast, simple, and on-site ATP monitoring. Herein, a unique, convenient, and label-free point-of-care sensing strategy based on novel copper coordination polymer nanoflowers (CuCPNFs) was fabricated for multimode (UV-vis, photothermal, and RGB values) onsite ATP determination with high selectivity, sensitivity, and accuracy. The resulting CuCPNFs with a 3D hierarchical structure exhibit the ATP-triggered decomposition behavior because the competitive coordination between ATP and the copper ions of CuCPNFs can result in the formation of ATP-Cu, which reveals preeminent peroxidase mimics activity and can accelerate the oxidation of 3, 3', 5, 5'-tetramethylbenzidine (TMB) to form oxTMB. During this process, the detection system displayed not only color changes but also a strong NIR laser-driven photothermal effect. Thus, the photothermal and color signal variations are easily monitored by a portable thermometer and a smartphone. This multimode point-of-care platform can meet the requirements of onsite, without bulky equipment, accuracy, and reliability all at once, greatly enhancing its application in practice and paving a new way in ATP analysis.

Dual-signal fluorescence aptasensing system for adenosine triphosphate assisting by MoS2 nanosheets

Adenosine triphosphate (ATP) has an irreplaceable role in the maintenance of many physiological processes and biological functions, and can be employed as an indicator of many diseases. In this work, we constructed a simple and sensitive dual-signal fluorescence aptasensing system for ATP detection with berberine as the signal reporter, ATP-aptamer as the recognition unit and MoS2 nanosheets as the signal amplification. In the absence of ATP, berberine can bind to the single-stranded DNA (ssDNA) of ATP-aptamer and selectively assemble on the surface of MoS2 nanosheets, leading to the fluorescence quenching of bererbine based on the fluorescence resonance energy transfer, denoted by "OFF". Accordingly, the fluorescence anisotropy signal is enhanced due to restriction on rotate of the fluorescent probe and denoted as "ON". Conversely, in the presence of ATP, it specifically interacts with ATP-aptamer and switches the free-curled single-stranded of ATP-aptamer to the G-quadruplex structure of ATP-aptamer/ATP/berberine, causing the detachment from the surface of the MoS2 nanosheet. Accordingly, the fluorescence signal was reversed from "OFF" to "ON", and the fluorescence anisotropy signal was turned "ON" to "OFF". The developed aptasensing system achieved a desirable sensitivity of 40.0 nM with fluorescent mode, and of 20.8 nM with fluorescent anisotropic mode. The sensing system has demonstrated high quality detection performance in human serum sample, and obtained the satisfactory recovery results for fluorescent of 93.0-108.5%, fluorescent anisotropic of 96.4-106.7%.

Recent Advances in Electrochemical Detection of Cell Energy Metabolism

Cell energy metabolism is a complex and multifaceted process by which some of the most important nutrients, particularly glucose and other sugars, are transformed into energy. This complexity is a result of dynamic interactions between multiple components, including ions, metabolic intermediates, and products that arise from biochemical reactions, such as glycolysis and mitochondrial oxidative phosphorylation (OXPHOS), the two main metabolic pathways that provide adenosine triphosphate (ATP), the main source of chemical energy driving various physiological activities. Impaired cell energy metabolism and perturbations or dysfunctions in associated metabolites are frequently implicated in numerous diseases, such as diabetes, cancer, and neurodegenerative and cardiovascular disorders. As a result, altered metabolites hold value as potential disease biomarkers. Electrochemical biosensors are attractive devices for the early diagnosis of many diseases and disorders based on biomarkers due to their advantages of efficiency, simplicity, low cost, high sensitivity, and high selectivity in the detection of anomalies in cellular energy metabolism, including key metabolites involved in glycolysis and mitochondrial processes, such as glucose, lactate, nicotinamide adenine dinucleotide (NADH), reactive oxygen species (ROS), glutamate, and ATP, both in vivo and in vitro. This paper offers a detailed examination of electrochemical biosensors for the detection of glycolytic and mitochondrial metabolites, along with their many applications in cell chips and wearable sensors.

Perspective-Assessing Electrochemical, Aptamer-Based Sensors for Dynamic Monitoring of Cellular Signaling

Electrochemical, aptamer-based (E-AB) sensors provide a generalizable strategy to quantitatively detect a variety of targets including small molecules and proteins. The key signaling attributes of E-AB sensors (sensitivity, selectivity, specificity, and reagentless and dynamic sensing ability) make them well suited to monitor dynamic processes in complex environments. A key bioanalytical challenge that could benefit from the detection capabilities of E-AB sensors is that of cell signaling, which involves the release of molecular messengers into the extracellular space. Here, we provide a perspective on why E-AB sensors are suited for this measurement, sensor requirements, and pioneering examples of cellular signaling measurements.

ATP-triggered highly sensitive probes for super-resolution mitochondrial imaging and low-dose bioimaging

Adenosine triphosphate (ATP), mainly produced in mitochondria, plays an important role in various pathological processes such as inflammation and acute liver injury. Fluorescence imaging is a powerful tool for imaging tissue structure and function in vivo. To date, the lack of biocompatible ATP probes with bright fluorescence emission has hindered their application in basic research and clinical trials. Here, we report a method for preparing ATP probes using a ZIF-90 potting dye, which produces bright ATP probes by encapsulating a modified high fluorescence quantum yield dye into a ZIF-90 skeleton. The nanoprobe does not fluoresce due to the coating. ATP can cooperate with Zn²⁺ to decompose the nanoprobe structure, release the dye and restore the fluorescence. Both nanoprobes ORhBSO₂@ZIF-90 and SiRhBSO₂@ZIF-90 showed higher sensitivity than the reported ATP nanoprobes with detection limits of 7.56 μM and 6.6 μM, and with lower doses (10 μg mL^-1) of probes for cell imaging. In addition, SiRhBSO₂@ZIF-90 has also been successfully used in the liver injury model. The ZIF-90 encapsulation strategy can retain the high fluorescence quantum yield and improve the biocompatibility of the dye.

Near-Infrared Fluorescent Nanoprobes for Adenosine Triphosphate-Guided Imaging in Cancer and Fatty Liver Mice

Adenosine triphosphate (ATP), as an indispensable biomolecule, is the main energy source of cells and is used as a marker for diseases such as cancer and fatty liver. It is of great significance to design a near-infrared fluorescent nanoprobe with excellent performance and apply it to various disease models. Here, a near-infrared fluorescent nanoprobe (ZIF-90@SiR) based on a zeolitic imidazole framework is proposed. The fluorescent nanoprobes are synthesized by encapsulating the dye (SiR) into the framework of ZIF-90. Upon the addition of ATP, the structure of the ZIF-90@SiR nanoprobe is disrupted and SiR is released to generate near-infrared fluorescence at 670 nm. In the process of ATP detection, ZIF-90@SiR shows high sensitivity and good selectivity. Moreover, the ZIF-90@SiR nanoprobe has good biocompatibility due to its low toxicity to cells. It is used for fluorescence imaging of ATP in living cells and thus distinguishing normal cells and cancer cells, as well as distinguishing fatty liver cells. Due to excellent near-infrared fluorescence properties, the ZIF-90@SiR nanoprobe can not only distinguish normal mice and tumor mice but also differentiate normal mice and fatty liver mice for the first time.

Cu2+-mediated turn-on fluorescence biosensor based on DNA-templated silver nanoclusters for label-free and sensitive detection of adenosine triphosphate

A Cu²⁺-mediated turn-on fluorescence biosensor based on the DNA-templated green-emitting silver nanoclusters (DNA@g-AgNCs) was developed for label-free and sensitive detection of adenosine 5'-triphosphate (ATP). Cu²⁺ was able to quench the bright green fluorescence of DNA@g-AgNCs because of the coordination and photoinduced electron transfer between DNA@g-AgNCs and Cu²⁺. Therefore, a unique and effective fluorescence biosensor can be constructed with the formation of DNA@g-AgNCs/Cu²⁺/ATP ternary-competition system. With the introduction of ATP, the DNA@g-AgNCs/Cu²⁺ fluorescence sensing system will be disrupted and the fluorescence of DNA@g-AgNCs was recovered due to higher affinity of ATP towards Cu²⁺. On the basis of this feature, the DNA@g-AgNCs/Cu²⁺ fluorescence sensing system demonstrated quantitative determination of ATP in the range 0.05 - 3 μM and a detection limit of 16 nM. Moreover, the fluorescence sensing system was successfully applied to the quantitative determination of ATP in human urine and serum samples with recoveries ranging from 98.6 to 106.5%, showing great promise to provide  a label-free, cost-efficient, and rapid platform for ATP-related clinical disease diagnosis.

Simultaneous Monitoring of the Adenosine Triphosphate Levels in the Cytoplasm and Nucleus of a Single Cell with a Single Nanowire-Based Fluorescent Biosensor

Simultaneous monitoring of the ATP levels at various sites of a single cell is crucial for revealing the ATP-related processes and diseases. In this work, we rationally fabricated single nanowire-based fluorescence biosensors, by which the ATP levels of the cytoplasm and nucleus in a single cell can be simultaneously monitored with a high spatial resolution. Utilizing the as-fabricated single nanowire biosensor, we demonstrated that the ATP levels of the cytoplasm were around 20-30% lower than that of the nucleus in both L929 and HeLa cells. Observing the ATP fluctuation of the cytoplasm and nucleus of the L929 and HeLa cells stimulated by Ca²⁺, oligomycin, or under cisplatin-induced apoptosis, we found that the ATP levels at two cellular sites exhibited discriminative changes, revealing the different mechanisms of the ATP at these two cellular sites in response to the stimulations.

Electrochemical Aptamer Biosensor Based on ATP-Induced 2D DNA Structure Switching for Rapid and Ultrasensitive Detection of ATP

Herein, a two-dimensional (2D) DNA structure with multiple ATP aptamers was elegantly designed to establish an electrochemical biosensor for rapid and sensitive detection of ATP based on ATP-induced structure switching. Concretely, the prepared 2D DNA structure containing numerous ATP aptamers as ATP-specific toehold switches could not only immobilize a large number of methylene blue (MB) for generating a remarkable electrochemical signal, but also greatly increase the local concentration of ATP aptamers to obviously enhance the capture efficiency of ATP. Once the target ATP interacted with the toehold switches, the 2D DNA structure could be sharply collapsed to trigger the burst release of MB from the electrode surface, ultimately resulting in a significantly decreased electrochemical signal for ultrasensitive detection of target ATP over a short period of time. Impressively, by dexterously adjusting the length of the ATP-specific toehold switches to 15-base, optimization of the binding affinity between ATP and the toehold switches was achieved for cutting down the detection time to 30 min and achieving a low detection limit of 0.3 pM, which addressed the shortcoming of time-consuming and poor sensitivity in the previous sensors with a small quantity of ATP aptamers and deficient binding affinity to ATP. Consequently, this strategy opened a promising avenue for ultrasensitive and rapid detection of various biomolecules in biomedical application and disease diagnosis.

Fluorescent Aptasensor for Highly Specific Detection of ATP Using a Newly Screened Aptamer

Owing to the significant roles of adenosine triphosphate (ATP) in diverse biological processes, ATP level is used to research and evaluate the physiological processes of organisms. Aptamer-based biosensors have been widely reported to achieve this purpose, which are superior in their flexible biosensing mechanism, with a high sensitivity and good biocompatibility; however, the aptamers currently used for ATP detection have a poor ability to discriminate ATP from adenosine diphosphate (ADP) and adenosine monophosphate (AMP). Herein, an ATP-specific aptamer was screened and applied to construct a fluorescent aptasensor for ATP by using graphene oxide (GO) and strand displacement amplification (SDA). The fluorescence intensity of the sensor is linearly related to the concentration of ATP within 0.1 μM to 25 μM under optimal experimental conditions, and the detection limit is 33.85 nM. The biosensor exhibits a satisfactory specificity for ATP. Moreover, the experimental results indicate that the biosensor can be applied to determine the ATP in human serum. In conclusion, the screened aptamer and the biosensor have promising applications in the determination of the real energy charge level and ATP content in a complex biological system.

Portable and sensitive detection of non-glucose target by enzyme-encapsulated metal-organic-framework using personal glucose meter

Personal glucose meter (PGM) is one of the most commercially available POC (point-of-care) devices for monitoring the level of glucose reliably, yet its non-glucose quantification ability is limited since such strategy needs ingenious interface design and tedious enzyme conjugation. Herein, we constructed a portable and sensitive platform that can detect non-glucose target by combining enzyme-encapsulated zeolitic imidazole framework-90 (ZIF-90) with personal glucose meter. ZIF-90 is an ideal carrier and susceptor due to the extraordinary capability of packaging enzyme and stimuli-responsiveness. We selected adenosine-5'-triphosphate (ATP) as the target model of non-glucose analytes. Upon ATP-induced decomposition of MOF, the released enzyme (glucose oxidase or invertase) catalyzed substrate and gave rise to the change of the glucose concentration for PGM assay. This method determined ATP with a remarkably sensitivity of 233 nM and effective recovery in real serum samples. Our strategy provides a facile and practical approach for measuring the non-glucose target using PGM, and could potentially be applied in bimolecular detection in point-of-care diagnosis.

Porous Fe3O4@COF-Immobilized gold nanoparticles with excellent catalytic performance for sensitive electrochemical detection of ATP

In this work, a "signal-off" electrochemical biosensor was established for sensitive detection of adenosine triphosphate (ATP) based on Fe₃O₄@covalent organic framework-immobilized gold nanoparticles (Fe₃O₄@COF-Au NPs) porous composite material as a nanocarrier. The proposed Fe₃O₄@COF-Au NPs could effectively confine Au NPs in the uniform channels of the Fe₃O₄@COF, which successfully avoided Au NPs aggregation to a certain extent and provided a comparatively independent and stable micro-environment via its hydrophobic porous nanochannels, thereby owning excellent electro-catalytic performance for the reduction of 4-nitrophenol. Moreover, the Fe₃O₄@COF-Au NPs nanomaterials were served as functional platform for immobilizing DNA substrate (S0), which was used to bind with the conversion product (S1) of the target ATP for subsequent branched hybridization chain reaction (b-HCR) to form dendritic DNA strands to hinder electron transfer between Fe₃O₄@COF-Au NPs and 4-nitrophenol, finally achieving sensitive detection of ATP with a wide linear range of 5 pM-50 μM and a low detection limit of 1.6 pM. Such strategy provides a multifunctional immobilized platform for the sensitive detection of ATP and a versatile strategy for monitoring other biomolecules.

Molecularly assembled graphdiyne with atomic sites for ultrafast and real-time detection of nitric oxide in cell assays

Nitric oxide as a signal molecule participates in a variety of physiological and pathological processes but its real-time detection in cell assays still faces challenging because of the trace amount, short half-life and easy conversion to other substances. We report here a rational design by assembling highly π-conjugated and small capacitive gaphdiyne (GDY) with a coordination complex of hemin (HEM) into a molecularly assembled material of GDY/HEM to achieve ultrafast and real-time monitoring of nitric oxide in cell assays. GDY comprising alkynyl C atoms can hybridize with the HEM to enable strong π-π interaction and atomic dispersion of iron sites while avoiding the formation of catalytically inactive dimer for the HEM. These characteristics make the GDY/HEM an excellent sensing material towards nitric oxide, which has an ultrafast response time of 0.95 s, a low detection limit of 7 nM and long linear range up to 151.38 μΜ. The GDY/HEM realizes real-time monitoring nitric oxide released from cancer and normal cells, demonstrating its capability for cell analysis.

Detection of the effect of polydopamine (PDA)-coated polydimethylsiloxane (PDMS) substrates on the release of H2O2 from a single HeLa cell

Endogenous H₂O₂ generated by a single HeLa cell that was adhered on the PDA-coated PDMS substrates under 25 mM glucose culture conditions was detected using a home-built photoelectric dual detection platform. With PMA as the stimulus, the cell released a small amount of H₂O₂ and its mitochondrial membrane potential (MMP) decrease was smaller, compared with that on the PDMS substrates.

Photoactivated Biosensing Process for Dictated ATP Detection in Single Living Cells

The subcellular distribution of adenosine 5'-triphosphate (ATP) and the concentration of ATP in living cells dynamically fluctuate with time during different cell cycles. The dictated activation of the biosensing process in living cells enables the spatiotemporal target detection in single living cells. Herein, a kind of o-nitrobenzylphosphate ester hairpin nucleic acid was introduced as a photoresponsive DNA probe for light-activated ATP detection in single living cells. Two methods to spatiotemporally activate the probe in single living cells were discussed. One method was the usage of the micrometer-sized optical fiber (about 5 μm) to guide the UV light (λ = 365 nm) to selectively activate the photoresponsive DNA probe in single living cells. The second method involved a two-photon laser confocal scanning microscope to selectively irradiate the photoresponsive DNA probes confined in single living cells via two-photon irradiation (λ = 740 nm). ATP aptamer integrated in the activated DNA probes selectively interacted with the target ATP, resulting in dictated signal generation. Furthermore, the photoactivated biosensing process enables dictated dual-model ATP detection in single living cells with "Signal-ON" fluorescence signal and "Signal-OFF" electrochemical signal outputs. The developed photoactivated biosensor for dictated ATP detection with high spatiotemporal resolution in single living cells at a desired time and desired place suggests the possibility to monitor biomarkers during different cell cycles.

A Novel Electrochemical Aptasensor for the Ultrasensitive Detection of Adenosine Triphosphate Based on DNA-Templated Copolymers

Adenosine triphosphate (ATP) is a small but significant biological molecule that plays an important role in regulating cellular metabolism processes. Accurate and sensitive analytical techniques for detecting ATP are urgently needed. Herein, a new electrochemical aptasensor was designed in light of DNA-templated copolymers that parallel to the electrode for sensitive gauging of ATP. The ATP aptamer decorated by the electronic medium ferrocene can be regarded as a ″bridge″ connecting two DNA-templated copolymers. When ATP exists, because of the extraordinary binding selectivity of DNA-templated copolymers for target ATP, the rapid electron transfer of ferrocene was beneficial to the sensitive detection of target ATP. Specifically, our parallel DNA copolymers are more stable than upright DNA copolymers and have a faster signal transmission because of the close distance to the electrode; meanwhile, the nonspecific pollution is less. Consequently, the developed novel aptasensor exhibited a wide range of linear response toward ATP that was from 0.1 to 10 000 pM and high selectivity with a detection limit down to 11.5 fM. The electrochemical aptasensor has a broad application prospect in the detection of small biological molecules.

Ex vivo and in vivo fluorescence detection and imaging of adenosine triphosphate

Background

Ex vivo and in vivo detection and imaging of adenosine triphosphate (ATP) is critically important for the diagnosis and treatment of diseases, which still remains challenges up to present.

Results

We herein demonstrate that ATP could be fluorescently detected and imaged ex vivo and in vivo. In particular, we fabricate a kind of fluorescent ATP probes, which are made of titanium carbide (TC) nanosheets modified with the ROX-tagged ATP-aptamer (TC/Apt). In the constructed TC/Apt, TC shows superior quenching efficiency against ROX (e.g., ~ 97%). While in the presence of ATP, ROX-tagged aptamer is released from TC surface, leading to the recovery of fluorescence of ROX under the 545-nm excitation. Consequently, a wide dynamic range from 1 μM to 1.5 mM ATP and a high sensitivity with a limit of detection (LOD) down to 0.2 μM ATP can be readily achieved by the prepared TC/Apt. We further demonstrate that the as-prepared TC/Apt probe is feasible for accurate discrimination of ATP in different samples including living cells, body fluids (e.g., mouse serum, mouse urine and human serum) and mouse tumor models.

Conclusions

Fluorescence detection and imaging of ATP could be readily achieved in living cells, body fluids (e.g., urine and serum), as well as mouse tumor model through a new kind of fluorescent ATP nanoprobes, offering new powerful tools for the treatment of diseases related to abnormal fluctuation of ATP concentration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00930-4.

Amine-functionalized carbon-fiber microelectrodes for enhanced ATP detection with fast-scan cyclic voltammetry

Here, we provide evidence that functionalizing the carbon-fiber surface with amines significantly improves direct electrochemical adenosine triphosphate (ATP) detection with fast-scan cyclic voltammetry (FSCV). ATP is an important extracellular signaling molecule throughout the body and can function as a neurotransmitter in the brain. Several methods have been developed over the years to monitor and quantitate ATP signaling in cells and tissues; however, many of them are limited in temporal resolution or are not capable of measuring ATP directly. FSCV at carbon-fiber microelectrodes is a widely used technique to measure neurotransmitters in real-time. Many electrode treatments have been developed to study the interaction of cationic compounds like dopamine at the carbon surface yet studies investigating how to improve anionic compounds, like ATP, at the carbon fiber surface are lacking. In this work, carbon-fibers were treated with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) which reacts with carboxylic acid groups on the carbon surface followed by reaction with ethylenediamine (EDA) to produce NH2-functionalized carbon surfaces. Overall, we a 5.2 ± 2.5-fold increase in ATP current with an approximately 9-fold increase in amine functionality, as analyzed by X-ray Photoelectron Spectroscopy, on the carbon surface was observed after modification with EDC-EDA. This provides evidence that amine-rich surfaces improve interactions with ATP on the surface. This study provides a detailed analysis of ATP interaction at carbon surfaces and ultimately a method to improve direct and rapid neurological ATP detection in the future.