Indoor Localization of Hand-Held OCT Probe Using Visual Odometry and Real-Time Segmentation Using Deep Learning.

OBJECTIVE: Optical coherence tomography (OCT) is an established medical imaging modality that has found widespread use due to its ability to visualize tissue structures at a high resolution. Currently, OCT hand-held imaging probes lack positional information, making it difficult or even impossible to link a specific image to the location it was originally obtained. In this study, we propose a camera-based localization method to track and record the scanner position in real-time, as well as providing a deep learning-based segmentation method. METHODS: We used camera-based visual odometry (VO) and simultaneous mapping and localization (SLAM) to compute and visualize the location of a hand-held OCT imaging probe. A deep convolutional neural network (CNN) was used for kidney tubule lumens segmentation. RESULTS: The mean absolute error (MAE) and the standard deviation (STD) for 1D translation were found to be 0.15 mm and 0.26mm respectively. For 2D translation, the MAE and STD were found to be 0.85 mm and 0.50 mm, respectively. The dice coefficient of the segmentation method was 0.7. The t-statistic of the T-test between predicted and actual average densities and predicted and actual average diameters were 7.7547e-13 and 2.2288e-15 respectively. We also experimented on a preserved kidney utilizing our localization method with automatic segmentation. Comparisons of the average density maps and average diameter maps were made between the 3D comprehensive scan and VO system scan. CONCLUSION: Our results demonstrate that VO can track the probe location at high accuracy, and provides a user-friendly visualization tool to review OCT 2D images in 3D space. It also indicates that deep learning can provide high accuracy and high speed for segmentation. SIGNIFICANCE: The proposed methods can be potentially used to predict delayed graft function (DGF) in kidney transplantation.

Dynamic Visualization and Quantification of Single Vesicle Opening and Content by Coupling Vesicle Impact Electrochemical Cytometry with Confocal Microscopy.

In this work, we introduce a novel method for visualization and quantitative measurement of the vesicle opening process by correlation of vesicle impact electrochemical cytometry (VIEC) with confocal microscopy. We have used a fluorophore conjugated to lipids to label the vesicle membrane and manipulate the membrane properties, which appears to make the membrane more susceptible to electroporation. The neurotransmitters inside the vesicles were visualized by use of a fluorescence false neurotransmitter 511 (FFN 511) through accumulation inside the vesicle via the neuronal vesicular monoamine transporter 2 (VMAT 2). Optical and electrochemical measurements of single vesicle electroporation were carried out using an in-house, disk-shaped, gold-modified ITO (Au/ITO) microelectrode device (5 nm thick, 33 µm diameter), which simultaneously acted as an electrode surface for VIEC and an optically transparent surface for confocal microscopy. As a result, the processes of adsorption, electroporation, and opening of single vesicles followed by neurotransmitter release on the Au/ITO surface have been simultaneously visualized and measured. Three opening patterns of single isolated vesicles were frequently observed. Comparing the vesicle opening patterns with their corresponding VIEC spikes, we propose that the behavior of the vesicular membrane on the electrode surface, including the adsorption time, residence time before vesicle opening, and the retention time after vesicle opening, are closely related to the vesicle content and size. Large vesicles with high content tend to adsorb to the electrode faster with higher frequency, followed by a shorter residence time before releasing their content, and their membrane remains on the electrode surface longer compared to the small vesicles with low content. With this approach, we start to unravel the vesicle opening process and to examine the fundamentals of exocytosis, supporting the proposed mechanism of partial or subquantal release in exocytosis.

A near-infrared light-controlled, ultrasensitive one-step photoelectrochemical detection of dual cell apoptosis indicators in living cancer cells.

Here, a near-infrared (NIR) light-controlled, ultrasensitive one-step photoelectrochemical (PEC) strategy was constructed to simultaneously detect cell apoptosis indicators, phosphatidylserine (Pho) and sodium-potassium adenosine triphosphatase (Sat), on living cancer cells. Using NIR light as excitation, the signal probe methylene blue (Tagkinetic) could be released, leading to a gradually decreased photocurrent signal Ikinetic; meanwhile, the photocurrent Istable of the signal probe carbon quantum dots (Tagstable) remained stable. The simultaneous detection of Pho and Sat could be achieved based on rapid one-step PEC detection under single NIR light with the assistance of a smart signal decryption strategy with Ikinetic and Istable. Importantly, this proposal provides more effective drug candidates with milder pharmaceutical effect but improved safety.

[Ru(dcbpy)2 dppz]2+ /Fullerene Cosensitized PTB7-Th for Ultrasensitive Photoelectrochemical MicroRNA Assay.

A new cosensitization photoelectrochemical (PEC) strategy was established by using a donor-acceptor-type photoactive material, poly{4,8-bis[5-(2-ethylhexyl)thiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl} (PTB7-Th), as a signal indicator, which was cosensitized with bis(4,4'dicarboxyl-2,2'-bipyridyl)(4,5,9,14-tetraazabenzo[b]triphenylene)ruthenium(II) ([Ru(dcbpy)2 dppz]2+ ) embedded in the grooves of the DNA duplex and fullerene (nano-C60 ) immobilized on the surface of DNA nanoflowers for microRNA assay. [Ru(dcbpy)2 dppz]2+ and nano-C60 could effectively enhance the photoelectric conversion efficiency (PCE) of PTB7-Th as a result of well-matched energy levels among nano-C60 , [Ru(dcbpy)2 dppz]2+ and PTB7-Th, leading to a clearly enhanced photocurrent signal. Meanwhile, a target recycling magnification technique based on duplex-specific nuclease was applied in this work to obtain higher detection sensitivity. The proposed biosensor demonstrated excellent analytical properties within a linear detection range of 2.5 fm to 2.5 nm and a limit of detection down to 0.83 fm. Impressively, this cosensitization PEC strategy offers an effective and convenient avenue to significantly improve the PCE of a photoactive material, resulting in a remarkably improved photocurrent signal for ultrasensitive and highly accurate detection of various targets.

Cosensitization Strategy with Cascade Energy Level Arrangement for Ultrasensitive Photoelectrochemical Protein Detection.

Here, a photoelectrochemical (PEC) biosensor was established by a cosensitization strategy with cascade energy level arrangement for ultrasensitive detection of prostate-specific antigen (PSA). The proposed cosensitization strategy was based on the well-matched energy level arrangement of four kinds of organic photoactive materials, in which poly{4,8-bis[5-(2-ethylhexyl)thiophen-2-yl]benzo[1,2- b:4,5- b']dithiophene-2,6-diyl- alt-3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4- b]thiophene-4,6-diyl} (PTB7-Th) was used as the photoactive material and perylenetetracarboxyl diimide (PDI), fullerene (nano-C60), and polyaniline (PANI) were employed as the sensitizers. The resulting PTB7-Th/PDI/nano-C60/PANI cascade cosensitization structure with narrow energy level gradient (<0.54 eV) could effectively improve electron transfer capability, obviously raise light energy utilization and significantly enhance photoelectric conversion efficiency, leading to dramatically enhanced photocurrent response. Using PSA as a target model, the proposed PEC biosensor exhibited high sensitivity and excellent stability with a wide detection range from 1 fg/mL to 0.1 ng/mL and a detection limit of 0.43 fg/mL. Moreover, the proposed PEC biosensor provides a cascade cosensitization strategy that could significantly improve PEC performances and open up a promising platform to establish high selectivity, stability, and ultrasensitive analytical techniques.

An ATP-fueled nucleic acid signal amplification strategy for highly sensitive microRNA detection.

Herein, an adenosine triphosphate (ATP)-fueled nucleic acid signal amplification strategy based on toehold-mediated strand displacement (TMSD) and fluorescence resonance energy transfer (FRET) was proposed for highly sensitive detection of microRNA-21. More importantly, the target microRNA-21 could be regenerated with ATP as the fuel rather than a nucleotide segment in conventional approaches, which made the proposed strategy simple and efficient due to the high affinity and strength of the aptamer-target interaction.

An ultrasensitive photoelectrochemical biosensor based on [Ru(dcbpy)2dppz]2+/Rose Bengal dyes co-sensitized fullerene for DNA detection.

Though preferable progresses have been achieved to improve the photoelectric performance of fullerene (C60 NPs) by sensitized structure in photoelectrochemical (PEC) field, further application inevitably suffers from the inherent scarcities of heavy metal-involved quantum dots as sensitizers containing restricted sensitization effect, complex preparation and biological toxicity. In this work, a PEC biosensor based on [Ru(dcbpy)2dppz]2+/Rose Bengal dyes co-sensitized C60 NPs was constructed for ultrasensitive DNA (a fragment sequence of p53 gene) detection. With the merits of low toxicity and accessible operation, [Ru(dcbpy)2dppz]2+/Rose Bengal dyes exhibited a further sensitization efficiency towards C60 NPs. Through modifying wide band gap C60 NPs with two narrower band gap dyes ([Ru(dcbpy)2dppz]2+ and Rose Bengal) to form a cascade-type energy band structure, the photoelectric conversion of C60 NPs was significantly improved and the visible light absorption was markedly promoted, leading to an exceptional photocurrent signal. Additionally, Nt.BstNB I enzyme-assisted target recycling amplification was employed to convert a limited quantity of target to numerous SiO2 NPs-labeled DNA sequences (the signal quencher), resulting in a sharp decrement of photocurrent since a dramatic increment of steric hindrance on the modified electrode surface, which was performed to quantitatively estimate target. The proposed PEC biosensor for DNA detection possessed a wide linear range from 0.1 fM to 1 nM with a calculated detection limit of 37 aM. This work opened up an intriguing avenue for determination of various targets such as DNAs, microRNAs and proteins, and exhibited desirable application potential in the clinic researches, cancer therapies and other related subjects.

Ultrasensitive Photoelectrochemical Biosensor Based on DNA Tetrahedron as Nanocarrier for Efficient Immobilization of CdTe QDs-Methylene Blue as Signal Probe with Near-Zero Background Noise.

Usually, photoelectrochemical (PEC) assays were devoted to the direct modification of photoactive materials on sensing interface, thereby producing high initial signal and unneglected background noise, which could further result in low sensitivity and restricted detection limit during the detection of targets. In this work, a PEC biosensor with near-zero background noise was established for ultrasensitive microRNA-141 (miRNA-141) detection based on DNA tetrahedron (TET) as nanocarrier for efficient immobilization of CdTe quantum dots (QDs)-Methylene Blue (MB) (TET-QDs-MB complex) as signal probe. First, CdTe QDs as PEC signal indicator was bound to the TET through DNA hybridizations. Then, massive MB as PEC signal enhancer was attached to DNA duplex of the TET immobilized with CdTe QDs via intercalation. Thereafter, the as-prepared TET-QDs-MB complex was considered as an efficient PEC signal probe owing to its excellent photovoltaic properties, thereby avoiding direct modification of photoactive materials on sensing interface and producing a near-zero background noise to improve the sensitivity of this PEC biosensor. Besides, the detection sensitivity could be further improved with the help of the duplex specific nuclease (DSN) enzyme-assisted target cycling amplification strategy. The proposed PEC biosensor performs a wide linear range from 50 aM to 50 pM with a low detection limit of 17 aM for miRNA-141, paving a new and promising horizon for highly accurate and ultrasensitive monitoring of multifarious analytes such as proteins, DNAs, and miRNAs in bioanalysis and disease diagnosis.

Ultrasensitive Fluorescent Assay Based on a Rolling-Circle-Amplification-Assisted Multisite-Strand-Displacement-Reaction Signal-Amplification Strategy.

Heavy metal ions are persistent environmental contaminants and pose a great threat to human health, which has prompted demand for new methods to selectively identify and detect these metal ions. Herein, a novel fluorescent assay based on a rolling-circle-amplification (RCA)-assisted multisite-strand-displacement-reaction (SDR) signal-amplification strategy was proposed for the ultrasensitive detection of heavy metal ions with lead ions (Pb2+) as a model. The proposed strategy not only achieved the target recycling but also introduced RCA induced by released DNAzyme. Most importantly, the RCA product was adapted as the initiator to provide multiple sites for SDR, which could displace signal duplexes from RCA products to effectively avoid the self-quenching of signal-probe assembly on the RCA product. Therefore, the amplification efficiency and the detection sensitivity could be improved significantly. As expected, the proposed strategy demonstrated good performance for the determination of Pb2+ with a linear range from 0.1 to 50 nM and a detection limit down to 0.03 nM. Using this strategy for intracellular-Pb2+ detection, a favorable property was obtained. Furthermore, the proposed strategy could be also expanded for the determination of microRNA, proteins, and other biomolecules, offering a novel avenue for environmental assays and clinical diagnostics.

A Highly Sensitive Photoelectrochemical Assay with Donor-Acceptor-Type Material as Photoactive Material and Polyaniline as Signal Enhancer.

In this work, a highly sensitive photoelectrochemical (PEC) assay was constructed based on a donor-acceptor (D-A)-type material, poly{4,8-bis[5-(2-ethylhexyl)thiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl- alt-3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4- b]thiophene-4,6-diyl} (PTB7-Th), as the photoactive material and polyaniline (PANI) in situ deposited on the surface of PTB7-Th as the signal enhancer. Initially, PTB7-Th, which contains an electron-rich unit as donor and an electron-deficient unit as acceptor with an easy separation of electron-hole pairs and intermolecular electron transfer, provided an excellent photocurrent response. Subsequently, an input target thrombin (TB) was converted to an output single-stranded DNA by a protein converting strategy. The obtained single-stranded DNA thus triggered a rolling circle amplification (RCA) to form a tandem multihairpin DNA nanostructure, which could function as a skeleton for immobilizing manganese porphyrin (MnTMPyP). In the presence of H2O2 and aniline, a PANI layer could be in situ deposited onto the tandem multihairpin DNA nanostructure with use of MnTMPyP as catalyst, leading to a significantly enhanced photocurrent for the detection of TB. The proposed PEC assay presented a wide detection range of 100 fM to 10 nM with a limit of detection (LOD) of 34.6 fM. Furthermore, the proposed strategy provides a PEC analysis method based on PTB7-Th that can significantly improve the photoelectric conversion efficiency and opens an intriguing avenue to establish low background, ultrasensitive, and highly stable analytical techniques.

A highly sensitive VEGF165 photoelectrochemical biosensor fabricated by assembly of aptamer bridged DNA networks.

We developed a novel "signal-off" photoelectrochemical (PEC) aptasensor based on an aptamer bridged DNA network structure for the sensitive detection of vascular endothelial growth factor (VEGF165), using g-C3N4 as photoactive material. The DNA network provides an excellent platform for the immobilization of methylene blue (MB), which can facilitate the electron transport through the DNA helix structure and suppress the recombination of electron-hole pairs generated by g-C3N4. In the presence of the target VEGF165, the DNA network can be destroyed adequately by the recognition between VEGF165 and the aptamer, resulting in the release of MB. Therefore, the originally enhanced electron transfer process could be inhibited, leading to a remarkable decrease of the photocurrent. A good linear relationship between the PEC signal and the logarithm of VEGF165 concentration over the range of 100fM to 10nM with a detection limit of 30 fM can be obtained. Our concept can be easily extended to develop aptasensors for the sensitive detection of different targets by triggering the release of the payloads from their corresponding aptamer bridged DNA networks.

Using p-type PbS Quantum Dots to Quench Photocurrent of Fullerene-Au NP@MoS2 Composite Structure for Ultrasensitive Photoelectrochemical Detection of ATP.

Ultrasensitive and rapid quantification of the universal energy currency adenosine triphosphate (ATP) is an extremely critical mission in clinical applications. In this work, a "signal-off" photoelectrochemical (PEC) biosensor was designed for ultrasensitive ATP detection based on a fullerene (C60)-decorated Au nanoparticle@MoS2 (C60-Au NP@MoS2) composite material as a signal indicator and a p-type PbS quantum dot (QD) as an efficient signal quencher. Modification of wide band gap C60 with narrow band gap MoS2 to form an ideal PEC signal indicator was proposed, which could significantly improve photocurrent conversion efficiency, leading to a desirable PEC signal. In the presence of p-type PbS QDs, the PEC signal of n-type C60-Au NP@MoS2 was effectively quenched because p-type PbS QDs could compete with C60-Au NP@MoS2 to consume light energy and electron donor. Besides, the conversion of a limited amount of target ATP into an amplified output PbS QD-labeled short DNA sequence (output S1) was achieved via target-mediated aptazyme cycling amplification strategy, facilitating ultrasensitive ATP detection. The proposed signal-off PEC strategy exhibited a wide linear range from 1.00 × 10-2 pM to 100 nM with a low detection limit of 3.30 fM. Importantly, this proposed strategy provides a promising platform to detect ATP at ultralow levels and has potential applications, including diagnosis of ATP-related diseases, monitoring of diseases progression and evaluation of prognosis.

Electrochemiluminescent Pb2+-Driven Circular Etching Sensor Coupled to a DNA Micronet-Carrier.

Herein, an ultrasensitive electrochemiluminescent (ECL) strategy was designed based on the fabrication of a multi-interface DNA micronet-carrier via layer by layer hybridization of double-stranded DNAzyme-substrate to immobilize large amounts of ECL indicator, [Ru(dcbpy)2dppz]2+, in double-strand DNA on the electrode surface, generating enhanced ECL signals. When the double-stranded structures were cleaved circularly via Pb2+ in the detection sample, the ECL indicator was released, which resulted in a decreased ECL signal associated with the concentration of Pb2+, that had higher sensitivity and wider linear range. As a result, the developed ECL strategy exhibited a linear range from 50 pM to 500 µM with a detection limit of 4.73 pM, providing an alternative analytical strategy with excellent properties, including a high sensitivity and a wide linear range. Importantly, the ECL strategy could be readily expanded for various metal ions, proteins, nucleotide sequences, and cells, offering a simple and efficient technology for both environmentally safe assays and clinical diagnostics.

Universal Ratiometric Photoelectrochemical Bioassay with Target-Nucleotide Transduction-Amplification and Electron-Transfer Tunneling Distance Regulation Strategies for Ultrasensitive Determination of microRNA in Cells.

A universal ratiometric photoelectrochemical (PEC) bioassay, which could be readily expanded for ultrasensitive determination of various targets in complex biological matrixes, was established by coupling a target-nucleotide transduction-amplification with DNA nanomachine mediated electron-transfer tunneling distance regulation strategies. With the help of target-nucleotide transduction-amplification strategy, the one input target signal could be transducted to corresponding multiple output DNA signals by nucleotide specific recognition technology, simultaneously leading to an efficient signal amplification for target. Then the output DNA could initiate the formation of four-way junction DNA nanomachine through binding-induced combination, by which the electron-transfer tunneling distance between photoactive materials and sensing interface could be regulated, simultaneously resulting an enhanced photocurrent signal from SiO2@methylene blue (SiO2@MB) as wavelength-selective photoactive material in close proximity to sensing interface and a reduced photocurrent signal from another wavelength-selective photoactive material CdS quantum dots (CdS QDs) away from sensing interface for photocurrent signal ratio calculation. Using microRNA-141 (miRNA-141) as target model, the constructed biosensor demonstrated favorable accuracy and excellent sensitivity down to the femtomolar level. Impressively, the proposed assay overcame the heavy dependence of target on photoactive materials in current ratiometric PEC assay and demonstrated admirably universal applicability for determination of various targets such as metal ions, miRNAs, DNAs, and proteins by merely two different photoactive materials (SiO2@MB and CdS QDs), paving the way to application of universal ratiometric PEC assay in environmental tests, clinical diagnosis, and other related subjects.

An efficient target-intermediate recycling amplification strategy for ultrasensitive fluorescence assay of intracellular lead ions.

An ultrasensitive fluorescence assay for intracellular Pb2+ determination was proposed through target-intermediate recycling amplification based on metal-assisted DNAzyme catalysis and strand displacement reactions. Compared with only target recycling-based fluorescence assay with an M amplification ratio, the proposed assay could achieve an M × N amplification ratio to obtain an improved sensitivity by more than 10 times, in which M and N are the amplification ratios of target recycling and intermediate recycling, respectively. Remarkably, this proposed ultrasensitive fluorescence assay could be applied to the determination of various analytes with the well-designed detection probe, especially in intracellular assay, providing a promising tool for clinical diagnosis and biomedical detection.

A sensitive immunosensor via in situ enzymatically generating efficient quencher for electrochemiluminescence of iridium complexes doped SiO2 nanoparticles.

A sensitive electrochemiluminescent (ECL) sandwich immunosensor was proposed herein based on the tris (2-phenylpyridine) iridium [Ir(ppy)3] doped silica nanoparticles (SiO2@Ir) with improved ECL emission as signal probes and glucose oxidase (GOD)-based in situ enzymatic reaction to generate H2O2 for efficiently quenching the ECL emission of SiO2@Ir. Typically, the SiO2@Ir not only increased the loading amount of Ir(ppy)3 as ECL indicators with high ECL emission, but also improved their water-solubility, which efficiently enhanced the ECL emission. Furthermore, by the efficient quench effect of H2O2 from in situ glucose oxidase (GOD)-based enzymatic reaction on the ECL emission of SiO2@Ir, a signal-off ECL immunsensor could be established for sensitive assay. With N-terminal of the prohormone brain natriuretic peptide (BNPT) as a model, the proposed ECL assay performed high sensitivity and low detection limit. Importantly, the proposed sensitive ECL strategy was not only suitable for the detection of BNPT for acute myocardial infarction, but also revealed a new avenue for early diagnosis of various diseases via proteins, nucleotide sequence, microRNA and cells.

Ultrasensitive Assay for Telomerase Activity via Self-Enhanced Electrochemiluminescent Ruthenium Complex Doped Metal-Organic Frameworks with High Emission Efficiency.

Here, an ultrasensitive "off-on" electrochemiluminescence (ECL) biosensor was proposed for the determination of telomerase activity by using a self-enhanced ruthenium polyethylenimine (Ru-PEI) complex doped zeolitic imidazolate framework-8 (Ru-PEI@ZIF-8) with high ECL efficiency as an ECL indicator and an enzyme-assisted DNA cycle amplification strategy. The Ru-PEI@ZIF-8 nanocomposites were synthesized by self-enhanced Ru-PEI complex doping during the growth of zeolitic imidazolate framework-8 (ZIF-8), which presented high ECL efficiency and excellent stability. Furthermore, owing to the porosity of Ru-PEI@ZIF-8, the self-enhanced Ru-PEI complex in the outer layer and inner layer of self-enhanced Ru-PEI@ZIF-8 could be excited by electrons causing the utilization ratio of the self-enhanced ECL materials to be remarkably increased. To further improve the sensitivity of the proposed biosensor, the telomerase activity signal was converted into the trigger DNA signal which was further amplified by an enzyme-assisted DNA recycle-amplification strategy. The proposed ECL biosensor presented great performance for telomerase activity detection from 5 × 101 to 106 Hela cells with a detection limit of 11 cells. Moreover, this method was applied in the detection of telomerase activity from cancer cells treated with an anticancer drug, which indicated the proposed method held potential application value as an evaluation tool in anticancer drug screening.

Self-Enhanced Ultrasensitive Photoelectrochemical Biosensor Based on Nanocapsule Packaging Both Donor-Acceptor-Type Photoactive Material and Its Sensitizer.

In this work, a self-enhanced ultrasensitive photoelectrochemical (PEC) biosensor was established based on a functionalized nanocapsule packaging both donor-acceptor-type photoactive material and its sensitizer. The functionalized nanocapsule with self-enhanced PEC responses was achieved first by packaging both the donor-acceptor-type photoactive material (poly{4,8-bis[5-(2-ethylhexyl)thiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl}, PTB7-Th) and its sensitizer (nano-C60, fullerene) in poly(ethylene glycol) (PEG) to form a nanocapsule, which significantly enhanced PEC signal and stability of the PEC biosensor. Moreover, a quadratic enzymes-assisted target recycling amplification strategy was introduced to the system for ultrasensitive determination. Compared with other established PEC biosensors, our proposed self-enhanced approach showed higher effectivity, accuracy, sensitivity, and convenience without any addition of coreactant or sensitizers into the testing electrolyte for photocurrent amplification and performed excellent analytical properties for microRNA estimation down to femtomole level with microRNA-141 as a model. Additionally, the proposed PEC biosensor was employed for estimation of microRNA in different cancer cells and pharmacodynamic evaluation in cancer cells. This self-enhanced PEC strategy has laid the foundation for fabrication of simple, effective, and ultrasensitive PEC diagnostic devices, leading to the possibility for early diagnosis, timely stage estimation, and accurate prognosis judgment of disease.

An ultrasensitive "on-off-on" photoelectrochemical aptasensor based on signal amplification of a fullerene/CdTe quantum dots sensitized structure and efficient quenching by manganese porphyrin.

In this work, an ultrasensitive "on-off-on" photoelectrochemical (PEC) aptasensor was proposed based on the signal amplification of a fullerene/CdTe quantum dot (nano-C60/CdTe QDs) sensitized structure and efficient signal quenching of nano-C60/CdTe QDs by a manganese porphyrin (MnPP).

An electrochemical peptide cleavage-based biosensor for matrix metalloproteinase-2 detection with exonuclease III-assisted cycling signal amplification.

In this work, an electrochemical peptide biosensor was developed for matrix metalloproteinase-2 (MMP-2) detection by conversion of a peptide cleavage event into DNA detection with exonuclease III (Exo III)-assisted cycling signal amplification.