Ratiometric Fluorescent Probe for Real-Time Detection of ß-Galactosidase Activity in Lysosomes and Its Application in Drug-Induced Senescence Imaging.

Senescence is an important biological process, which leads to the gradual degradation of its physiological function and increases morbidity and mortality. Herein, a novel ratiometric fluorescent probe (P1) was constructed by using benzothiazolyl acetonitrile dye as fluorophore, exhibiting significantly enhanced blue-shifted emission to indicate the activity of ß-galactosidase (ß-gal), a commonly used biomarker for the detection of senescent cells. After incubation with ß-gal, the excimer emission of P1 at 620 nm was weakened, while the emission at 533 nm was significantly enhanced, forming an obvious ratiometric probe with high sensitivity and low detection limit (2.7 mU·mL-1). More importantly, probe P1 can locate lysosomes accurately, allowing us to monitor the emergence of living cell senescence in real time. P1 was successfully used to detect ß-gal activity in PC-12 cells, Hep G2 cells, and RAW 264.7 cells. It showed strong green fluorescence signal in senescent cells and red fluorescence signal in normal cells, indicating that it can detect endogenous senescence-related ß-gal content in living cells. For in vivo drug-induced senescence imaging, after 5 weeks of injection of D-galactose or hydroxyurea, the mice showed significant fluorescence enhancement in specific channels to indicate the activity of ß-gal in vivo. At the same time, the senescence of cell-specific organs and skin tissues at the organ level were also detected, which proved that the drug-induced senescence of brain, skin, and muscle tissues was the most serious. These results supported the important application value of P1 in senescence biomedical research.

Enzyme-Instructed Host-Guest Assembly/Disassembly for Biomedical Applications.

Compared with the normal assembly/disassembly approaches, enzyme-instructed host-guest assembly/disassembly strategies due to their superior biocompatibility and specificity for specific substrates, can more effectively and precisely release molecules at lesions for reflecting in vivo biological events. Specifically, due to the over-expression of enzymes in specific tissues, the assembly/disassembly processes can directly occur on the pathological sites (or regions of interest), thus these enzyme-instructed processes are widely and effectively used for disease treatment or precise bioimaging. Based on it, we introduce the concept and major strategies of enzyme-instructed host-guest assembly/disassembly, illustrate their importance in the diagnosis and treatment of diseases, and review their advances in biomedical applications. Further, the challenges of these strategies in the clinic and future tendencies are also prospected.

Designed Polyhydroxyproline Helical Peptide with Ultrarobust Antifouling Capability for Electrochemical Sensing in Diverse Complex Biological Fluids.

Developing a generalized strategy for the nonfouling detection of biomarkers in diverse biological fluids presents a significant challenge. Herein, a polyhydroxyproline helical peptide (PHHP) was designed and adopted to fabricate electrochemical microsensors capable of detecting targets in various biological media. The PHHP possessed unique properties such as strong hydrophilicity, rigid structure, and lack of ionizable side-chain groups. Compared with common zwitterionic peptides (ZIPs), the PHHP exhibited similar antifouling capability but exceptional stability, allowing its antifouling performance to be unaffected by environmental alteration. The PHHP can prevent biofouling even in fluctuating pH conditions, high ionic strength environments, and the presence of high-valence ions and resist the protease hydrolysis. The PHHP-modified carbon fiber microelectrode was further immobilized with an aptamer to construct an antifouling microsensor for cortisol detection across diverse biofluids, and the microsensor exhibited acceptable accuracy and higher sensitivity than the ELISA method. In addition, different biological samples of mice were collected in situ using a microsensing device, and cortisol levels were analyzed in each specifically tailored region. This nonfouling sensing strategy based on PHHP allows a comprehensive assessment of biomarkers in both spatial and temporal dimensions in diverse biological environments, holding promising potential for early disease diagnosis and real-time health monitoring.

Ultrasensitive Ratiometric Electrochemiluminescence Sensor with an Efficient Antifouling and Antibacterial Interface of PSBMA@SiO2-MXene for Oxytetracycline Trace Detection in the Marine Environment.

The sensitivity and accuracy of electrochemiluminescence (ECL) sensors for detecting small-molecule pollutants in environmental water are affected not only by nonspecific adsorption of proteins and other molecules but also by bacterial interference. Therefore, there is an urgent need to develop an ECL sensor with antifouling and antibacterial functions for water environment monitoring. Herein, a highly efficient antifouling sensing interface (PSBMA@SiO2-MXene) based on zwitterionic sulfobetaine methacrylate (SBMA) antifouling nanospheres (NPs) and two-dimensional MXene nanosheets was designed for the sensitive detection of oxytetracycline (OTC), an antibiotic small-molecule pollutant. Specifically, SBMA with good hydrophilicity and electrical neutrality was connected to SiO2 NPs, thus effectively reducing protein and bacterial adsorption and improving stability. Second, MXene with a high specific surface area was selected as the carrier to load more antifouling NPs, which greatly improves the antifouling performance. Meanwhile, the introduction of MXene also enhances the conductivity of the antifouling interface. In addition, a ratio-based sensing strategy was designed to further improve the detection accuracy and sensitivity of the sensor by utilizing Au@luminol as an internal standard factor. Based on antifouling and antibacterial interfaces, as well as internal standard and ratiometric sensing strategies, the detection range of the proposed sensor was 0.1 ng/mL to 100 µg/mL, with a detection limit of 0.023 ng/mL, achieving trace dynamic monitoring of antibiotics in complex aqueous media.

Designed Multifunctional Isopeptide for Enhanced Annexin A1 Biosensing Based on Peptide-Protein Interactions in Human Blood.

Specific peptide-protein interactions play an important role in biosensing systems based on functional peptides; however, the non-specific interactions with unrelated biomolecules and poor proteolytic stability restrict the clinical application of natural peptides. Here, we leveraged a self-designed multifunctional isopeptide (MISP) to construct an electrochemical biosensing platform for annexin A1 (ANXA1) detection in human blood. The MISP was designed to contain two parts: an antifouling cyclotide cyclo-C(EK)4 and a d-amino acid-containing carbohydrate-mimetic recognizing peptide IF-7 (D-IF7) connected by the isopeptide bond. We have discussed the properties of the cyclotide and illustrated its unique advantage over the natural linear antifouling peptides by molecular dynamics simulations, and the results were further confirmed by dissipative quartz crystal microbalance (QCM-D). In addition, through electrochemical experiments and fluorescence imaging experiments, we demonstrated that the MISP-based biosensor possessed excellent antifouling ability and proteinase hydrolysis stability. Interestingly, the assaying results of the MISP-biosensor were consistent with those of the commercial ANXA1 kits in a variety of healthy and ANXA1-upregulated clinical blood samples, and, more importantly, for the analysis of blood samples with lower ANXA1 expressions, the sensing capability of the biosensor was greatly superior to that of the kits because of the lower detection limit of the MISP-biosensor. This biosensing platform based on the designed MISP offers enormous potential for achieving accurate biomarker detection with robust operation in complex biological samples.

pH-Switched Near-Infrared Fluorescent Strategy for Ratiometric Detection of ONOO- in Lysosomes and Precise Imaging of Oxidative Stress in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is well-known as a kind of autoimmune disease, which brings unbearable pain to the patients by multiple organ complications besides arthritis. To date, RA can be hardly cured, but early diagnosis and standard treatment can relieve symptoms and pain. Therefore, an effective tool to assist the early diagnosis of RA deserves considerable attention. On account of the overexpressed ONOO- during the early stage of RA, a near-infrared (NIR) receptor, Lyso-Cy, is proposed in this work by linker chemistry to expand the conjugated rhodamine framework by cyanine groups. Contributed by the pH-sensitive spiral ring in rhodamine, receptor Lyso-Cy has been found to be workable in lysosomes specifically, which was confirmed by the pH-dependent spectra with a narrow responding region and a well-calculated pKa value of 5.81. We presented an excellent ratiometric sensing protocol for ONOO- in an acidic environment, which was also available for targeting ONOO- in lysosomes selectively. This innovative dual-targeting responsive design is expected to be promising for assisting RA diagnosis at an early stage with respect to the joint inflammatory model established in this work at the organism level.

Spirooxindol alkaloids from Voacanga africana: Targeting biofilm of MBLs producing Escherichia coli.

Seven rarely spirooxindole alkaloids, voagafricines A-G (1-7) were isolated from the stem barks of Voacanga africana. Their structures were unambiguously elucidated by comprehensive spectroscopic data and electronic circular dichroism (ECD) analyses. 1 and 2 possess a unique indoleone system in conjugation with a 3,4'-decahydroquinoline spiral ring originating from seco-quinolhiddin core of the precursor, furthermore 1 undergo decarburization formed a novel C-3-nor monoterpenoid indole. All isolates were evaluated for their antibacterial activities against MBLs producing Escherichia coli strains. Compounds 1 and 7 were found to be potent inhibitors against E. coli 298 and 140 by targeting biofilm. Possible interaction sites of 1 and 7 with biofilm were preliminarily explored by means of molecular docking.

Ratiometric antifouling electrochemical biosensors based on designed Y-shaped peptide and MXene loaded with Au@ZIF-67 and methylene blue.

Based on the designed inverted Y-shaped peptide and MXene nanocomposite (MXene-Au@ZIF-67), a ratiometric anti-pollution electrochemical biosensor was designed and applied to the detection of biomarkers in serum. Au@ZIF-67 inserted into the interior of MXene can not only prevent the accumulation of MXene but also provide a large amounts of binding sites for capturing biomolecules. A designed multifunctional Y-shaped peptide containing anchoring, antifouling, and recognition sequences was anchored onto MXene-Au@ZIF-67 through Au-S bonds. Electrochemical signal molecules, ferrocenecarboxylic acid (Fc) and methylene blue (MB), were modified to another end of multifunctional peptide and interior of MXene-Au@ZIF-67, respectively, to produce a ratiometric electrochemical signal. We selected prostate specific antigen (PSA) as the model compound. PSA specifically recognizes and cleaves the recognition segment in the Y-shaped peptide, and the signal of Fc is reduced, while the signal of MB remains unchanged. The ratiometric strategy endows the present biosensor high accuracy and sensitivity with a detection limit of 0.85 pg/mL. In addition, the sensing surface has good antifouling ability due to the antifouling sequence of the two branching parts of the Y-shaped peptide. More importantly, by replacing the recognition segment of peptides also other targets are accessible, indicating the potential application of the universal detection strategy to the detection of various biomarkers in clinical diagnosis.

Antifouling Electrochemical Biosensor Based on the Designed Functional Peptide and the Electrodeposited Conducting Polymer for CTC Analysis in Human Blood.

Circulating tumor cells (CTCs) are considered reliable cancer biomarkers for the liquid biopsy of many types of tumors. The direct detection of CTCs in human blood with normal biosensors, however, remains challenging because of severe biofouling in blood that contains various proteins and a large number of cells. Herein, we report the construction of an antifouling electrochemical biosensor capable of assaying CTCs directly in blood, based on a designed multifunctional peptide and the electrodeposited conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT). The designed peptide possesses antifouling capability in complex biological media and specific recognition ability to capture breast cancer cells MCF-7. Meanwhile, electrodeposited PEDOT can promote electron transfer at the sensing interface, improve the signal-to-noise ratio for the detection, and thus enhance the sensitivity of the biosensor. The integration of the multifunctional peptide and conducting polymer PEDOT ensures that the developed biosensor is able to perform directly in blood samples without purification or separation. The antifouling electrochemical biosensor for the detection of MCF-7 cells exhibits a wide linear range over 4 orders, with a limit of detection (LOD) of 17 cells mL-1. More interestingly, even when performing in 25% human blood, the biosensor still retains a linear response with an LOD of 22 cells mL-1, without suffering significantly from biofouling in real blood. This work provides a promising strategy for the direct analysis of CTCs in human blood without a complicated pretreatment, and it may find practical application in the liquid biopsy of cancers.

Phthalocyanine-Based Nanoassembly with Switchable Fluorescence and Photoactivities for Tumor Imaging and Phototherapy.

Switchable theranostics are of great interest for accurate tumor imaging and targeted therapy. Here, we develop smart engineering to construct nanostructured phthalocyanines self-assembled by amphiphilic zinc phthalocyanines (ZnPcs) and hydrophobic copper phthalocyanines (CuPcs) (ZnPc(PEG)5:CuPc-N, where ZnPc(PEG)5 is monosubstituted ZnPcs with pentaethylene glycol as the substituent). The fluorescence and reactive oxygen species generation of ZnPc(PEG)5:CuPc-N can be triggered depending on the membrane of the tumor cells for the imaging and photoactivities. Concerning the stability in blood circulation, the surface of the nanocomplex is coated with polydopamine, which responds to the tumor acidic microenvironment. ZnPc(PEG)5 and CuPc focus on photodynamic and photothermal properties, respectively, and can be stimulated by a single laser beam, endowing ZnPc(PEG)5:CuPc-N a combined antitumor effect from evaluations both in vitro and in vivo. In our study, the mechanism of switchable theranostics, the strategy of combined photodynamic and photothermal therapy, and the smart nanoengineering technology of phthalocyanines with poor water solubility can be applied to other phthalocyanines or phthalocyanine-like phototherapy agents.

Denatured bovine serum albumin hydrogel-based electrochemical biosensors for detection of IgG.

An antifouling sensing surface was constructed by crosslinking two-dimensional nanomaterial MXene with bovine serum albumin (BSA) denatured by urea previously. The immunoglobulin G (IgG) capture peptide was then modified to the surface to construct a highly selective antifouling electrochemical biosensor. Due to the large specific surface area and good electrical conductivity of MXene, the sensitivity of the biosensor is significantly enhanced. The biosensor at a working potential of around - 0.18 V (vs. Ag/AgCl) provides a wide linear detection range (0.1 ng/mL to 10 µg/mL) for IgG with a limit of detection of 23 pg/mL (3σ/k). The result is consistent with that obtained from the commercial enzyme-linked immunosorbent kit. Compared with BSA, which is usually used as a passivator or blocker for biosensing platforms, the hydrogel formed through the peptide chain obtained from BSA with good hydrophilicity can provide a better antifouling sensing surface to resist nonspecific adsorption. The prepared biosensor can quantitatively detect the concentration of IgG in complex human serum with high sensitivity. Thus, the antifouling sensing surface constructed without expensive antifouling materials and complex process is expected to develop as a variety of electrochemical biosensors and used for the clinical testing of biomarkers. Graphical abstract An antifouling sensing surface was constructed by crosslinking two-dimensional nanomaterial MXene with bovine serum albumin (BSA) denatured by urea previously. The immunoglobulin G (IgG) capture peptide was then modified to the surface to construct a highly selective antifouling electrochemical biosensor.

Electrochemical Biosensor with Enhanced Antifouling Capability for COVID-19 Nucleic Acid Detection in Complex Biological Media.

Biofouling caused by the accumulation of biomolecules on sensing surfaces is one of the major problems and challenges to realize the practical application of electrochemical biosensors, and an effective way to counter this problem is the construction of antifouling biosensors. Herein, an antifouling electrochemical biosensor was constructed based on electropolymerized polyaniline (PANI) nanowires and newly designed peptides for the detection of the COVID-19 N-gene. The inverted Y-shaped peptides were designed with excellent antifouling properties and two anchoring branches, and their antifouling performances against proteins and complex biological media were investigated using different approaches. Based on the biotin-streptavidin affinity system, biotin-labeled probes specific to the N-gene (nucleocapsid phosphoprotein) of COVID-19 were immobilized onto the peptide-coated PANI nanowires, forming a highly sensitive and antifouling electrochemical sensing interface for the detection of COVID-19 nucleic acid. The antifouling genosensor demonstrated a wide linear range (10-14 to 10-9 M) and an exceptional low detection limit (3.5 fM). The remarkable performance of the genosensor derives from the high peak current of PANI, which is chosen as the sensing signal, and the extraordinary antifouling properties of designed peptides, which guarantee accurate detection in complex systems. These crucial features represent essential elements for future rapid and decentralized clinical testing.

Anti-Fouling Magnetic Beads Combined with Signal Amplification Strategies for Ultra-Sensitive and Selective Electrochemiluminescence Detection of MicroRNAs in Complex Biological Media.

Herein, an electrochemiluminescence (ECL) microRNA biosensor based on anti-fouling magnetic beads (MBs) and two signal amplification strategies was developed. The newly designed anti-fouling dendritic peptide was wrapped on the surfaces of MBs to make them resistant to nonspecific adsorption of biomolecules in complex biological samples so as to realize accurate and selective target recognition. One of the amplification strategies was achieved through nucleic acid cycle amplification based on the DNAzyme on the surfaces of MBs. Then, the output DNA generated by the nucleic acid cycle amplification program stimulated the hybrid chain reaction (HCR) process on the modified electrode surface to generate the other amplification of the ECL response. Titanium dioxide nanoneedles (TiO2 NNs), as a co-reaction accelerator of the Ru(bpy)2(cpaphen)2+ and tripropylamine (TPrA) system, were wrapped with the electrodeposited polyaniline (PANI) on the electrode surface to enhance the ECL intensity of Ru(bpy)2(cpaphen)2+. The conducting polymer PANI can not only immobilize the TiO2 NNs but also improve the conductivity of the modified electrodes. The biosensor exhibited ultra-high sensitivity and excellent selectivity toward the detection of miRNA 21, with a detection limit of 0.13 fM. More importantly, with the anti-fouling MBs as a unique separation tool, this ECL biosensor was capable of assaying targets in complex biological media such as serum and cell lysate.

Simultaneous Targeted Analysis of GGT and Its H-Type mRNA in HepG2 Cells Based on Degradable Silicon Nanomaterials.

Most important physiological processes in live cells are usually maintained by the interaction of multiple related biomolecules; the multi-target simultaneous analysis of these related molecules can better reflect the dynamic changes of their biological regulatory processes, providing more comprehensive information for diseases diagnosis and research. Herein, we have constructed the degradable multifunctional silica nanomaterials from the prepared degradable organic silicon source and further established degradable composite nanoprobes (DCNPs). The low toxicity of DCNPs could reduce the impact on normal physiological processes in cells and achieve the needs of living cell analysis applications; by the loading of the gamma-glutamyltransferase (GGT) activity-identification probe (Cy-GGT) and surface nucleic acid-recognizing molecular beacon (hairpin) modification, the DCNP realized the simultaneous image analysis of GGT and its related H-type mutated GGT mRNA (H-mRNA) in HepG2 cells and their quantitative detection in vitro. Compared with the traditional multi-target analysis strategy, the lack of targets' physiological mechanism connection was improved, and the combined application of small molecular probes and nucleic acid analysis structures was realized under the control of the cross-influence. This strategy is expected to provide a new direction for the design of multi-target analysis in live cells and provide more accurate analytical tools for clinical research and cancer therapy.

AND-Logic Strategy for Accurate Analysis of Alzheimer's Disease via Fluorescent Probe Lighted Up by Two Specific Biomarkers.

Alzheimer's disease (AD) has become a global threat to the elderly health with a short survival time after diagnosis. Due to the asymptomatic stage during the early development, patients are usually diagnosed at the middle or late stage. Therefore, an efficient tool for AD early diagnosis deserves considerable attention, which could make a significant contribution to the treatment intervention. A fluorescent probe has been widely applied for detecting and visualizing species of interest in vitro and in vivo, and the proper reaction between the probe and analytes is responsible for the fluorescence change to provide a lighting-on or ratiometric responsive pattern with satisfactory sensing behavior. In this work, we report the first attempt to build up an AND-logic probe P2 for AD accuracy diagnosis taking butyrylcholinesterase (BChE) and reactive oxygen species (ROSs) as dual targets. Upon the co-stimulation by these two factors through enzymatic hydrolysis and redox reaction, the NIR emission could be readily turned on. This AND sensing pattern avoided the false-positive response effectively, and other diseases sharing one biomarker could hardly induce a NIR fluorescence response. The sensing assay has also been confirmed to be feasible in vitro and in vivo with good sensibility and selectivity. It is worth mentioning that the probe structure has been optimized in terms of the linkage length. This study shows that probe P2 with a connecting arm of medium length (one methylene, n = 1) has superior sensing performance, promising to provide a reference for the relative structure design.

Fluorescent detection of microRNA-21 in MCF-7 cells based on multifunctional gold nanorods and the integration of chemotherapy and phototherapy.

MicroRNA-21 is an important biomarker of tumor early prediction and metastasis, and its accurate detection is of great significance for tumor diagnosis and treatment. It will be a meaningful work to combine the detection of RNA with chemotherapy and photothermal therapy on the same composite material. Herein, we designed a multifunctional nanocomposite based on gold nanorods (AuNRs), making use of microRNA-triggered drug release and near-infrared photothermal effect, which has been developed for cancer therapy and microRNA-21detection. Firstly, the AuNRs with photothermal effect were synthesized as carriers for drug delivery. Then the surface of gold nanorods was modified by functional DNA chains to provide an efficient site for doxorubicin (DOX) loading. Finally, folic acid was introduced to achieve the targeted treatment of MCF-7 cells. The microRNA competed with the double-stranded DNA, resulting in the release of DOX and the recovery of fluorescence signal located at 595 nm with an excitation of 488 nm effectively. The nano-biosensor could not only achieve dual-function of diagnosis and treatment of cancer cells, but also accomplish the detection of microRNA in tumor cells. It showed a high selectivity for microRNA-21 determination with a limit of detection (LOD) of 2.1 nM from the linear relationship from 1.0 × 10-5 M to 5.0 × 10-7 M. This scheme provides an outstanding strategy for cell imaging, treatment, and detection, which serves as a promising candidate in the field of biomedical research.

New Monoterpenoid Indoles with Osteoclast Activities from Gelsemium elegans.

The well-known toxic medicine Gelsemium elegans is widely and historically used to treat bone fracture and skin ulcers by the folk people of China. Two new monoterpenoid indole alkaloids, gelselegandines D and E, together with the known analogue gelegamine A were isolated from G. elegans. Their structures were elucidated by means of spectroscopic techniques and quantum chemical calculations. All isolated compounds were tested for the effects on RANKL-induced osteoclast formation. Interestingly, gelselegandine E and gelegamine A, respectively, showed significant promoting and inhibitory activities on osteoclastogenesis, while gelselegandine D had no activity under the same concentration. This work suggested the different configurations for the carbons near the C-19/20 oxygen rings of the isolated compounds may be the key active groups on osteoclast formation and provided the evidence for the rationality as the traditional treatment for bone-related diseases of G. elegans.

Designed Three-in-One Peptides with Anchoring, Antifouling, and Recognizing Capabilities for Highly Sensitive and Low-Fouling Electrochemical Sensing in Complex Biological Media.

Nonspecific adsorption is of great concern for electrochemical biosensors performing in complex biological media, and various antifouling materials have been introduced into the sensing interfaces to improve the antifouling capability of different biosensors. However, for most of the biosensors with antifouling materials and sensing probes coexisting in the sensing interfaces, either the antifouling materials will impair the sensing performances or the sensing probes will affect the antifouling ability. Herein, a facile and efficient antifouling biosensor was developed based on a newly designed three-in-one peptide with anchoring, antifouling, and recognizing capabilities. One end of the designed peptide is a unique anchoring part that is rich in amine groups, and this part can be anchored to the poly(3,4-ethylenedioxythiophene) (PEDOT)-citrate film electrodeposited on a glassy carbon electrode. The other end of the peptide is a recognizing part that can specifically bind to the aminopeptidase N (APN) and human hepatocellular carcinoma cells (HepG2 cells). Meanwhile, the middle part of the peptide, together with the anchoring part, was designed to be antifouling. With this designed multifunctional peptide, highly sensitive and low-fouling biosensors capable of assaying target APN and HepG2 cells in complex biological media can be easily prepared, with detection limits of 0.4 ng·mL-1 and 20 cells·mL-1, respectively. This antifouling biosensor is feasible for practical target detection in real complex samples, and it is highly expected that this peptide designing strategy may be extended to the development of various antifouling biosensors.

Copolymer-Based Fluorescence Nanosensor for In Situ Imaging of Homocysteine in the Liver and Kidney of Diabetic Mice.

Homocysteine (Hcy) is one of the important biomarkers of clinical diagnosis, which is closely related to the occurrence and development of many diseases. Current analysis methods have difficulties in detecting Hcy in cells and living organisms. As a powerful technique, fluorescence methods combined the laser confocal imaging technology can achieve real-time visual tracking in cells and in vivo. Herein, we establish a conjugated copolymer-based fluorescence nanosensor (DPA-PFNP-Cu(II)) using the connected 2,7-dibromofluorene and 4,7-bis (2-bromothiophen-5-yl)-2-1-3-benzothiadiazole as the main chain. The competitive coordination between Hcy and Cu(II) allows the fluorescence of the polymer off to on. Finally, the nanosensor is applied for in situ imaging of Hcy levels in the kidney and liver of diabetic mice and is found that Hcy levels were positively correlated with the degree of diabetes. Notably, the depth of tissue penetration of the nanosensor enables Hcy detection of the liver and kidney through in vivo imaging without damage. Two-photon imaging and in vivo imaging achieve consistent results, which correct each other, improving the accuracy of the test result. The present works provide a new imaging technique for studying the occurrence and development of diabetes and screening of new drugs for treatment at the living level.

Wip1 phosphatase deficiency impairs spatial learning and memory.

Spatial learning and memory are typically assessed to evaluate hippocampus-dependent cognitive and memory functions in vivo. Protein phosphorylation and dephosphorylation by kinases and phosphatases play critical roles in spatial learning and memory. Here we report that the Wip1 phosphatase is essential for spatial learning, with knockout mice lacking Wip1 phosphatase exhibiting dysfunctional spatial cognition. Aberrant phosphorylation of the Wip1 substrates p38, ATM, and p53 were observed in the hippocampi of Wip1-/- mice, but only p38 inhibition reversed impairments in long-term potentiation in Wip1-knockout mice. p38 inhibition consistently ameliorated the spatial learning dysfunction caused by Wip1 deficiency. Our results demonstrate that deletion of Wip1 phosphatase impairs hippocampus-dependent spatial learning and memory, with aberrant downstream p38 phosphorylation involved in this process and providing a potential therapeutic target.