Rational utilization of the rich light‐bio‐matter interplay taking place in single‐cell analysis represents a new technological direction in the field. The light‐fueled operation is expected to ...achieve advanced photoelectrochemical (PEC) single‐cell analysis with unknown possibilities. Here, a PEC nanoreactor capable of single‐cell sampling and near zero‐background Faradaic detection of intracellular microRNA (miR) is devised by the construction of a small reaction chamber accommodating the target‐triggered hybridization chain reaction for binding the metallointercalator of Ru(bpy)2(dppz)2+ as the signal reporter. Light stimulation of the dsDNA/metallointercalator adduct will induce the generation of photocurrents, underpinning a zero‐biased and near zero‐background PEC method toward Faradaic detection of non‐electrogenic miR at the single‐cell level. Using this nanotool, lower miR concentration in the near‐nucleus region than that in the main cytosol was revealed.
A photoelectrochemical nanoreactor was devised for single‐cell sampling and near zero‐background faradic detection of intracellular microRNA. This platform provided a new perspective for exploring light‐biomatter interplay toward single‐cell studies.
With reduced background and high sensitivity, photoelectrochemistry (PEC) may be applied as an intracellular nanotool and open a new technological direction of single‐cell study. Nevertheless, the ...present palette of single‐cell tools lacks such a PEC‐oriented solution. Here a dual‐functional photocathodic single‐cell nanotool capable of direct electroosmotic intracellular drug delivery and evaluation of oxidative stress is devised by engineering a target‐specific organic molecule/NiO/Ni film at the tip of a nanopipette. Specifically, the organic molecule probe serves simultaneously as the biorecognition element and sensitizer to synergize with p‐type NiO. Upon intracellular delivery at picoliter level, the oxidative stress effect will cause structural change of the organic probe, switching its optical absorption and altering the cathodic response. This work has revealed the potential of PEC single‐cell nanotool and extended the boundary of current single‐cell electroanalysis.
An integrated photocathodic nanotool was fabricated for dual‐functional intracellular drug delivery and evaluation of cellular oxidative stress in single live cell.
Single‐cell epigenetics is envisioned to decipher manifold epigenetic phenomena and to contribute to our accurate knowledge about basic epigenetic mechanisms. Engineered nanopipette technology has ...gained momentum in single‐cell studies; however, solutions to epigenetic questions remain unachieved. This study addresses the challenge by exploring N6‐methyladenine (m6A)‐bearing deoxyribozyme (DNAzyme) confined within a nanopipette for profiling a representative m6A‐modifying enzyme, fat mass and obesity‐associated protein (FTO). Electroosmotic intracellular extraction of FTO could remove the m6A and cause DNAzyme cleavage, leading to the altered ionic current signal. Because the cleavage can release a DNA sequence, we simultaneously program it as an antisense strand against FTO‐mRNA, intracellular injection of which has been shown to induce early stage apoptosis. This nanotool thus features the dual functions of studying single‐cell epigenetics and programmable gene regulation.
An integrated iontronic nanotool was developed for the study of single‐cell epigenetics and programmable gene regulation. With the nanotool, an N6‐methyladenine (m6A)‐modified deoxyribozyme (DNAzyme) was used for profiling a representative m6 A‐modifying enzyme, fat mass and obesity‐associated protein (FTO), which also released a DNA sequence that could be programmed as an antisense strand against intracellular FTO‐mRNA.
Single‐cell protein therapeutics is expected to promote our in‐depth understanding of how a specific protein with a therapeutic dosage treats the cell without population averaging. However, it has ...not yet been tackled by current single‐cell nanotools. We address this challenge by the use of a double‐barrel nanopipette, in which one lumen was used for electroosmotic cytosolic protein delivery and the other was customized for ionic evaluation of the consequence. Upon injection of protein DJ‐1 through the delivery lumen, upregulation of the antioxidant protein could protect neural PC‐12 cells against oxidative stress from phorbol myristate acetate exposure, as deduced by targeting of the cytosolic hydrogen peroxide by the detecting lumen. The nanotool developed in this study for single‐cell protein therapeutics provides a perspective for future single‐cell therapeutics involving different therapeutic modalities, such as peptides, enzymes and nucleic acids.
Electrochemical single‐cell protein therapeutics was devised with an engineered θ‐nanopipette and exemplified by protein DJ‐1 enabled neuroprotection. Upon DJ‐1 injection through the delivery lumen, upregulation of the antioxidant protein could protect neural PC‐12 cells against oxidative stress from phorbol myristate acetate exposure, as deduced by targeting of the cytosolic H2O2 by the detecting lumen.
Though significant advances are made in the arena of single‐cell electroanalysis, quantification of intracellular amino acids of human cells remains unsolved. Exemplified by l‐histidine (l‐His), this ...issue is addressed by a practical electrochemical nanotool synergizing the highly accessible nanopipette with commercially available synthetic DNAzyme. The fabricated nanotools are screened before operation of a single‐use manner, and the l‐His‐provoked cleavage of the DNA molecules can be sensibly transduced by the ionic current rectification response, the intrinsic property of nanopipette governed by its interior surface charges. Regional distribution of cytosolic l‐His level in human cells is electrochemically quantified for the first time, and time‐dependent drug treatment effects are further revealed. This work unveils the possibility of electrochemistry for quantification of cytosolic amino acids of a spatial‐ and time‐based manner and ultimately enables a better understanding of amino acid‐involved events in living cells.
The solution‐to‐electrochemical single‐cell analysis of intracellular amino acids is achieved by integrating nanopipette with specific DNAzyme and exemplified by targeting l‐histidine. It allowed minimally invasive detection with high sensitivity and selectivity. Drug treatment is also probed of a spatial‐ and time‐based manner.
This work proposes the concept of single‐cell microRNA (miR) therapy and proof‐of‐concept by engineering a nanopipette for high‐precision miR‐21‐targeted therapy in a single HeLa cell with sensitive ...photoelectrochemical (PEC) feedback. Targeting the representative oncogenic miR‐21, the as‐functionalized nanopipette permits direct intracellular drug administration with precisely controllable dosages, and the corresponding therapeutic effects can be sensitively transduced by a PEC sensing interface that selectively responds to the indicator level of cytosolic caspase‐3. The experimental results reveal that injection of ca. 4.4 × 10−20 mol miR‐21 inhibitor, i.e., 26488 copies, can cause the obvious therapeutic action in the targeted cell. This work features a solution to obtain the accurate knowledge of how a certain miR‐drug with specific dosages treats the cells and thus provides an insight into futuristic high‐precision clinical miR therapy using personalized medicine, provided that the prerequisite single‐cell experiments are courses of personalized customization.
The concept of high‐precision single‐cell microRNA therapy is proposed and devised by a functional nanopipette, which allows precise miR‐21 inhibitor delivery to induce cell apoptosis and responds selectively to caspase‐3 of a sensitive photoelectrochemical feedback. It can reveal what the precise drug amount can cause the effective therapeutic action.
Photonic (bio)electronic circuits and devices have been an enduring goal in modern photonics and electronics. Organic photoelectrochemical transistor (OPECT) interfacing light with biological world ...creates a substantial opportunity to this end due to the immense light−bio−matter interplay. Through modulating the invisible ionic circuit of organic electrochemical transistor (OECT) with a bipolar electrode (BPE) accommodating different semiconductor combinations, the unique photonic electronics toward logic and sensor applications are realized. Six combinations of BPEs are produced by the representative n‐type CdS/TiO2 and p‐type BiOI/NiO semiconductors, and the corresponding photonic characteristics and operation rationale are systematically investigated and explained. Designation of opto‐logic circuits and feasibility as a sensory platform are subsequently demonstrated. This work not only represents new photonic bioelectronics but also provides a generic mechanism for the design and development of advanced opto‐logics and bio‐analytics.
The ionic circuit of organic electrochemical transistor (OECT) is rationally modulated with bipolar electrode accommodating specific photoelectrochemical processes to realize photonic OECT with unique transfer characteristics and transient behaviors. The as‐developed optoelectronics can be applied as a generic and extensible platform for designation of new opto‐logic circuits and bio‐sensory systems.
Aim
Senescence of alveolar type II (AT2) cells is an important driver of pulmonary fibrosis. This study aimed to investigate whether and how dysregulation of hydrogen sulfide (H2S) production ...affected AT2 cell senescence, and then explored the effect of H2S on the communication between AT2 and fibroblasts.
Methods
ICR mice were intratracheally administered with bleomycin (3 mg/kg). Sodium hydrosulfide (NaHS, 28 μmol/kg/d) was intraperitoneally injected for 2 weeks. The H2S‐generating enzyme cystathionine‐β‐synthase (CBS) knockout heterozygous (CBS+/−) mice were used as a low H2S production model.
Results
Analysis of microarray datasets revealed downregulation of H2S‐generating enzymes in lung tissues of patients with pulmonary fibrosis. Decreased H2S production was correlated with higher levels of cell senescence markers p53 and p21 in bleomycin‐induced lung fibrosis. CBS+/− mice exhibited increased levels of p53 and p21. The numbers of AT2 cells positive for p53 and p21 were increased in CBS+/− mice as compared to control mice. H2S donor NaHS attenuated bleomycin‐induced AT2 cell senescence both in vivo and in vitro. H2S donor suppressed bleomycin‐induced senescence‐associated secretory phenotype (SASP) of AT2 cells via inhibiting p53/p21 pathway, consequently suppressing proliferation and myofibroblast transdifferentiation of fibroblasts. Mechanically, H2S suppressed p53 expression by enhancing the mouse double‐minute 2 homologue (MDM2)‐mediated ubiquitination and degradation of p53.
Conclusion
H2S inactivated p53‐p21 pathway, consequently suppressing AT2 cell senescence as well as cell communication between senescent AT2 cells and fibroblasts. Aberrant H2S synthesis may contribute to the development of pulmonary fibrosis through promoting the activation loop involving senescent AT2 cells and activated fibroblasts.
This work reports the construction of a miniaturized Ag/AgCl nanoelectrode on a nanopipette, which is capable of dual-functions of single-cell drug infusion and chloride detection and is envisioned ...to promote the study of chloride-correlated therapeutic effects.
A hollow Ag/AgCl nanoelectrode is developed for single-cell drug infusion and chloride detection.
Single-cell analysis (SCA) could provide in-depth understanding of cell biology yet is of great challenge. Many attempts have been made to develop novel techniques for SCA. Nanopipette-based ion ...current rectification (ICR) electroanalysis represents an emerging methodology to combat in this arena. In this review, the working rationale of ICR and its key regulation factors are discussed, followed by the sensing strategies established for SCA using illustrative examples. Future perspectives in this field are also proposed.
•Ion current rectification (ICR)-nanopipette technique for single-cell analysis (SCA) is reviewed.•The fundamentals, operation rationales, and the state of the art are discussed.•Trends and prospects of this field are presented.
