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Introducing magnetic order into a topological insulator via the magnetic proximity effect can break the time-reversal symmetry of the topological surface states, resulting in a variety of exotic physical phenomena that are expected to be applied in spintronic devices. However, in the topological insulator/ferromagnet heterostructures obtained so far, the interfacial hybridization is too weak and difficult to induce sufficiently strong magnetism in the topological insulator. In this work, we investigate the electrical transport properties of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures and demonstrate the presence of the magnetic proximity effect in them. The Curie temperature of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures was found to be increased by about 25 K. The coercive field was suppressed in the magnetoresistance; the Hall curves of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures exhibited different orientations and appeared non-linear behavior at high fields, and the anisotropic magnetoresistance changed from twofold rotational symmetry to quadruple symmetry. These provide direct evidence for the emergence of the magnetic proximity effect. This work will help to study the magnetic proximity effect in the topological insulators and paves the way for spintronic devices in the future.

Fluorescence imaging in the second near-infrared (NIR-II) window holds great promise for in vivo visualization of amyloid-β (Aβ) pathology, which can facilitate characterization and deep understanding of Alzheimer's disease (AD); however, it has been rarely exploited. Herein, we report the development of NIR-II fluorescent reporters with a donor-π-acceptor (D-π-A) architecture for specific detection of Aβ plaques in AD-model mice. Among all the designed probes, DMP2 exhibits the highest affinity to Aβ fibrils and can specifically activate its NIR-II fluorescence after binding to Aβ fibrils via suppressed twisted intramolecular charge transfer (TICT) effect. With suitable lipophilicity for ideal blood-brain barrier (BBB) penetrability and deep-tissue penetration of NIR-II fluorescence, DMP2 possesses specific detection of Aβ plaques in in vivo AD-model mice. Thus, this study presents a potential agent for non-invasive imaging of Aβ plaques and deep deciphering of AD progression. Ministry of Education (MOE) National Research Foundation (NRF) The authors thank the financial support from National Natural Science Foundation of China (22106115, 81901803, and 22274107), Jiangsu Specially Appointed Professorship, Natural Science Foundation of Jiangsu Province (BK20190830and BK20190811), Leading Talents of Innovation and Entrepreneurship of Gusu (ZXL2021457),and Soochow Technological Project(SYS2020082).K.P. thanks Singapore National Research Foundation(NRF)(NRF-NRFI07-2021-0005), and Singapore Ministry of Education, Academic Research Fund Tier 1 (2019-T1-002-045, RG125/19, RT05/20), Academic Research Fund Tier 2 (MOE-T2EP30220-0010; MOE-T2EP30221-0004), for the financial support.

Accurate prediction of the long-term extreme response of offshore structures is challenging for complex systems under varying marine environments. The long-term uncertainties come from the varying environmental parameters such as significant wave height and spectral peak period, while the short-term uncertainties are due to the random wave amplitudes and phases. The conventional environmental contour lines method provides a fast approximate way to estimate the extreme response by performing simulations along the environmental contours. However, the method is unconservative if the short-term uncertainties are neglected. Current methods to account for the short-term uncertainties are approximate and require an empirical parameter that is case-dependent. This paper presents a modified environmental contour line approach, based on introducing an additional multiplicative random variable to account for the short-term variability. It is efficient as additional simulations are performed only in the critical direction determined by the conventional approach. The method is first tested on a single-degree-of-freedom model representing the surge motion of a floating offshore structure. Subsequently, it is applied on the top riser stress of a catenary moored floating production system. Monte Carlo simulation is impractical here as a validation tool due to the extensive simulation time. Hence, the results are compared with subset simulation, which is known to be asymptotically unbiased.

Development of real-time non-invasive imaging probes to assess infiltration and activation of cytotoxic T cells (CTLs) is critical to predict the efficacy of cancer immunotherapy, which however remains challenging. Reported here is an activatable semiconducting polymer nanoprobe (SPNP) for near-infrared fluorescence (NIRF) and photoacoustic (PA) imaging of a biomarker (granzyme B) associated with activation of CTLs. SPNP comprises a semiconducting polymer (SP) conjugated with a granzyme B cleavable and dye-labeled peptide as the side chain, both of which emit NIRF and PA signals. After systemic administration, SPNP passively targets the tumor and in situ reacts with granzyme B to release the dye-labeled peptide, leading to decreased NIRF and PA signals from the dye but unchanged signals from the polymer. Such ratiometric NIRF and PA signals of SPNP correlate well with the expression level of granzyme B and intratumoral population of CTLs. Thus, this study not only presents the first PA probes for in vivo imaging of immune activation but also provides a molecular design strategy that can be generalized for molecular imaging of other immune-related biomarkers. Ministry of Education (MOE) Nanyang Technological University K.P. thanks Nanyang Technological University (Start-Up grant:M4081627) and the Singapore Ministry of Education Academic Research Fund Tier 1 (2019-T1-002-045,RG125/19) and Academic Research Fund Tier 2 (MOE2018-T2-2-042) for the financial support. This work was also supported by the National Natural Science Foundation of China (81703031 and 81672937).

Gratzel's dye-sensitized solar cells (DSSCs) can readily convert sunlight into electricity, attracting considerable attention of global scientists. The fabrication efficiency of DSSCs was greatly limited by the slow fabrication (∼3.5-24 h) of quasi-solid (QS) electrolytes to date. In this study, novel composites of SiO2 aerogel with graphene (GR), multi-walled carbon nanotubes, or polyaniline were proposed in the fabrication of QS-state electrolytes. The morphology of these composites was characterized. The gels with SiO2 aerogels as QS electrolytes of DSSCs can be rapidly cured in ∼3 s. Using the screen-printing technology, these QS electrolytes can be readily utilized to construct the QS-DSSC to provide high efficiency and great stability. The photovoltaic parameters and interfacial charge-transfer resistances of the QS-DSSC incorporated with our synthetic composites were investigated in detail. Specifically, the SiO2 aerogel composed of GR (SiO2@GR) as a gel can greatly improve the performance of QS-DSSCs up to 8.25%. It is likely that these SiO2 aerogel composite electrolytes could provide a rapid curing process in the preparation of QS-state DSSCs, which might be useful to promote the development of DSSCs for future industrialization.

Discriminative detection of invasive and noninvasive breast cancers is crucial for their effective treatment and prognosis. However, activatable probes able to do so in vivo are rare. Herein, we report an activatable polymeric reporter (P-Dex) that specifically turns on near-infrared (NIR) fluorescent and photoacoustic (PA) signals in response to the urokinase-type plasminogen activator (uPA) overexpressed in invasive breast cancer. P-Dex has a renal-clearable dextran backbone that is linked with a NIR dye caged with an uPA-cleavable peptide substrate. Such a molecular design allows P-Dex to passively target tumors, activate NIR fluorescence and PA signals to effectively distinguish invasive MDA-MB-231 breast cancer from noninvasive MCF-7 breast cancer, and ultimately undergo renal clearance to minimize the toxicity potential. Thus, this polymeric reporter holds great promise for the early detection of malignant breast cancer.

In vivo simultaneous visualization of multiple biomarkers is critical to accurately diagnose disease and decipher fundamental processes at a certain pathological evolution, which however is rarely exploited. Herein, a multimodal activatable imaging probe (P

Imaging to evaluate tumor-associated neutrophils (TANs) is imperative for cancer immunotherapy but remains challenging. We herein report an activatable semiconducting polymer nanoprobe (SPCy) for near-infrared fluorescence (NIRF) and photoacoustic (PA) imaging of neutrophil elastase (NE), a biomarker of TANs. SPCy comprises a semiconducting polymer conjugated with a hemicyanine (hemi-Cy) dye caged by a NE-cleavable peptide as the side chain. After systemic administration, SPCy passively targets the tumor and reacts with NE to "uncage" the hemi-Cy, leading to enhanced NIRF and PA signals of the hemi-Cy but unchanged signals of the SP. Such NE-activated ratiometric NIRF and enhanced PA signals of SPCy correlate with the intratumoral population of TANs. Thus, this study not only presents the first TAN-specific PA probe, but also provides a general molecular design strategy for PA imaging of other immune-related biomarkers to facilitate screening of cancer immunotherapeutics. Ministry of Education (MOE) This work was supported by the National Key Research and Development Program of China (2021YFA1101500). K.P. thanks Singapore Ministry of Education, Academic Research Fund Tier 1 (2019-T1-002-045, RG125/19, RT05/20) Academic Research Fund Tier 2 (MOE2018-T2-2-042; MOE-T2EP30220-0010) for the financial support.

In this study, the levels of airborne bacteria and fungi were tested in a female dormitory room; the effects of heating, relative humidity and number of occupants on indoor microorganisms were analyzed and the dose rate of exposure to microbes was assessed. The bacterial and fungal concentrations in the room ranged from 100 to several thousand CFU/m3, and the highest counts were observed in the morning (930 ± 1681 CFU/m3). Staphylococcus spp. and Micrococcus spp. were found in the dormitory. When the heating was on, the total bacterial and fungal counts were lower than when there was no heating. Moreover, statistically significant differences were observed for bacterial concentrations during the morning periods between the times when there was no heating and the times when there was heating. The number of occupants had an obvious positive effect on the total bacterial counts. Moreover, RH had no correlation with the airborne fungi in the dormitory, statistically. Furthermore, the highest dose rate from exposure to bacteria and fungi was observed during sleeping hours. The dose rate from exposure to airborne microorganisms in the dormitory was associated with the activity level in the room. These results helped to elucidate the threat of bioaerosols to the health of female occupants and provide guidance for protective measures.

Numerous polymeric agents have been widely applied in biology and medicine by virtue of the facile chemical modification, feasible nano-engineering approaches and fine-tuned pharmacokinetics. To endow polymeric imaging agents with ability to monitor and measure subtle molecular or cellular alterations at diseased sites, activatable polymeric probes that can elicit signal changes in response to biomolecular interactions or the analytes of interest have to be developed. Herein, this review aims to provide a systemic interpretation and summarization of the design methodology and imaging utility of recently emerged activatable polymeric probes. An introduction of activatable probes allowing for precise imaging and classification of polymeric imaging agents is reported first. Then, we give a detailed discussion of the contemporary design approaches toward activatable polymeric probes in diverse imaging modes for the detection of various stimuli and their imaging applications. Finally, current challenges and future advances are discussed and highlighted.

Src homology 3 (SH3) domains are small protein modules involved in the regulation of important cellular pathways such as proliferation and migration, which canonically prefer to recognize and inter...

Drug-induced acute kidney injury (AKI) with a high morbidity and mortality is poorly diagnosed in hospitals and deficiently evaluated in drug discovery. Here, we report the development of molecular renal probes (MRPs) with high renal clearance efficiency for in vivo optical imaging of drug-induced AKI. MRPs specifically activate their near-infrared fluorescence or chemiluminescence signals towards the prodromal biomarkers of AKI including the superoxide anion, N-acetyl-β-d-glucosaminidase and caspase-3, enabling an example of longitudinal imaging of multiple molecular events in the kidneys of living mice. Importantly, they in situ report the sequential occurrence of oxidative stress, lysosomal damage and cellular apoptosis, which precedes clinical manifestation of AKI (decreased glomerular filtration). Such an active imaging mechanism allows MRPs to non-invasively detect the onset of cisplatin-induced AKI at least 36 h earlier than the existing imaging methods. MRPs can also act as exogenous tracers for optical urinalysis that outperforms typical clinical/preclinical assays, demonstrating their clinical promise for early diagnosis of AKI. Chemiluminescent molecular renal probes have been developed and are shown to be capable of non-invasive real-time imaging of early-stage oxidative stress biomarkers of drug-induced acute kidney injury, and high renal clearance.

Background:Protein–peptide recognition plays an essential role in the orchestration and regulation of cell signaling networks, which is estimated to be responsible for up to 40% of biological interaction events in the human interactome and has recently been recognized as a new and attractive druggable target for drug development and disease intervention.Methods:We present a systematic review on the application of machine learning techniques in the quantitative modeling and prediction of protein–peptide binding affinity, particularly focusing on its implications for therapeutic peptide design. We also briefly introduce the physical quantities used to characterize protein–peptide affinity and attempt to extend the content of generalized machine learning methods.Results:Existing issues and future perspective on the statistical modeling and regression prediction of protein– peptide binding affinity are discussed.Conclusion:There is still a long way to go before establishment of general, reliable and efficient machine leaningbased protein–peptide affinity predictors.

Self-binding peptide (SBP) represents a novel biomolecular phenomenon spanning between folding and binding. It is a structurally independent, short peptide segment within a monomeric protein and fulfills biological function by dynamically binding to/unbinding from its target domain in the same monomer. Here, four representative SBP systems, including mouse proto-oncogene Vav, human retinoic acid receptor RARγ, fruit fly scaffold module INAD and crypto 14-3-3 protein Cp14b, are investigated systematically by using atomistic molecular dynamics (MD) simulations and post binding energetics analyses. The native bound structure, artificial unbound state and isolated peptide segment of SBP moieties in the four systems were constructed, analyzed and compared in detail. It is revealed that the SBP interaction with their targets is almost a binding phenomenon at single-molecule level, but presence of a polypeptide linker between the SBP and target can promote the binding efficiency since the linker restriction largely increases the probability of SBP–target encounters in a statistical physics point of view. In this respect, unlike classical peptide-mediated interactions where the intrinsically disordered peptides are folded into an ordered structure upon binding to their protein partners (folding-upon-binding), we herein propose SBPs as a new and reversed biological event that is naturally a folding phenomenon but exhibits a typical binding behavior (binding-upon-folding).

Afterglow imaging with long-lasting luminescence after cessation of light excitation provides opportunities for ultrasensitive molecular imaging; however, the lack of biologically compatible afterglow agents has impeded exploitation in clinical settings. This study presents a generic approach to transforming ordinary optical agents (including fluorescent polymers, dyes, and inorganic semiconductors) into afterglow luminescent nanoparticles (ALNPs). This approach integrates a cascade photoreaction into a single-particle entity, enabling ALNPs to chemically store photoenergy and spontaneously decay it in an energy-relay process. Not only can the afterglow profiles of ALNPs be finetuned to afford emission from visible to near-infrared (NIR) region, but also their intensities can be predicted by a mathematical model. The representative NIR ALNPs permit rapid detection of tumors in living mice with a signal-to-background ratio that is more than three orders of magnitude higher than that of NIR fluorescence. The biodegradability of the ALNPs further heightens their potential for ultrasensitive in vivo imaging. Afterglow luminescence is used to reduce background noise and increase sensitivity; however, biocompatible afterglow materials are limited. Here, the authors report on an approach to turn standard optical agents into afterglow nanoparticles and demonstrate the application in tumour imagining in vivo.

Multimodal imaging-guided therapy holds great potential for precise theranostics of cancer metastasis. However, imaging agents enabling the convergence of complementary modalities with therapeutic functions to achieve perfect theranostics have been less exploited. This study reports the construction of a multifunctional nanoagent (FIP-99mTc) that comprises Fe3O4 for magnetic resonance imaging, radioactive 99mTc for single-photon-emission computed tomography, and IR-1061 to serve for the second near-infrared fluorescence imaging, photoacoustic imaging, and photothermal therapy treatment of cancer metastasis. The nanoagent possessed superior multimodal imaging capability with high sensitivity and resolution attributing to the complement of all the imaging modalities. Moreover, the nanoagent showed ideal photothermal conversion ability to effectively kill tumor cells at low concentration and power laser irradiation. In the in vivo study, FIP-99mTc confirmed the fast accumulation and clear delineation of metastatic lymph nodes within 1 h after administration. Attributing to the efficient uptake and photothermal conversion, FIP-99mTc could raise the temperature of metastatic lymph nodes to 54 °C within 10 min laser irradiation, so as to facilitate tumor cell ablation. More importantly, FIP-99mTc not only played an active role in suppressing cancer growth in metastatic lymph nodes with high efficiency but also could effectively prevent further lung metastasis after resection of the primary tumor. This study proposes a simple but effective theranostic approach toward lymph node metastasis.

Grätzel's dye-sensitized solar cells (DSSCs) can readily convert sunlight into electricity, attracting considerable attention of global scientists. The fabrication efficiency of DSSCs was greatly limited by the slow fabrication (∼3.5-24 h) of quasi-solid (QS) electrolytes to date. In this study, novel composites of SiO

Many cell signaling pathways are orchestrated by the weak, transient, and reversible protein-protein interactions that are mediated by the binding of a short peptide segment in one protein (parent protein) to a globular domain in another (partner protein), known as peptide-mediated interactions (PMIs). Previous studies normally had an implicit hypothesis that a PMI is functionally equivalent or analogous to the protein-peptide interaction (PTI) involved in the PMI system, while ignoring parent context contribution to the peptide binding. Here, we perform a systematic investigation on the reasonability and applicability of the hypothesis at structural, energetic and dynamic levels. It is revealed that the context impacts PMIs primarily through conformational constraint of the peptide segments, which can (i) reduce the peptide flexibility and disorder in an unbound state, (ii) help the peptide conformational selection to fit the active pocket of partner proteins, and (iii) enhance the peptide packing tightness against the partners. Long, unstructured and/or middle-located peptide segments seem to be more vulnerable to their context than short, structured and/or terminal ones. The context is found to moderately or considerably improve both the binding affinity and specificity of PMIs as compared to their PTI counterparts; with the context support a peptide segment can contribute to ∼30-60% total binding energy of the whole PMI system, whereas the contribution is reduced to ∼5-50% when the context constraint is released. In addition, we also observe that peptide selectivity is largely impaired or even reversed upon stripping of their parent context (global selectivity decreases from 34.2 to 1.7-fold), by examining the crystal structures of full-length Src family kinases in an autoinhibitory state. Instead of the direct interaction and desolvation that are primarily concerned in traditional studies, peptide flexibility and the entropy penalty should also play a crucial role in the context effect on PMIs. Overall, we suggest that the context factor should not be ignored in most cases, particularly those with peptide segments that are long, highly disordered, and/or located at the middle region of their parent proteins.

A simple in situ self-assembly strategy for a novel series of highly ordered 3D hierarchical Co3O4@MnO2 core–shell hybrid materials with peculiar morphologies, uniform size and high quality has been successfully developed. The mechanisms of the morphology control, reaction process, product generation, calcining process, as well as the morphology evolution of Co3O4, the intermediates of Co3O4@C and Co3O4@MnO2 hybrid materials, have been investigated and clarified in detail. The core–shell Co3O4@MnO2 hybrid architectures have the advantages of morphological features, synergistic effects between core and shell, alternative products of Co3O4@C@MnO2 or Co3O4@MnO2, and facilitate electrolyte reactions. The 3D hierarchical Co3O4@MnO2 core–shell hybrid materials are used, for the first time, for two typical Co-based energy applications in photoelectric conversion devices of dye-sensitized solar cells (DSSCs) and the decomposition of an important solid rocket propellant, ammonium perchlorate (AP). With the 3D hierarchical Co3O4 core and ultrathin MnO2 shell, the developed hybrid materials exhibit superior performances and remarkable catalytic properties. As the alternative counter electrode of DSSCs, the developed Co3O4@MnO2 core–shell hybrid system exhibited an impressive performance with the conversion efficiency of 7.08%, which was improved by 26.4% and 13.3% as compared with the Co3O4 and Co3O4@C counterparts, respectively. As the catalyzer of AP decomposition, the Co3O4 material obviously decreased the decomposition temperatures by about 118–143 °C and increased the exothermic heat to 933–1228 J g−1. For the Co3O4@C counterpart, the decomposition temperatures were decreased by 120–131 °C with the increased exothermic heat of 1254–1306 J g−1. The addition of Co3O4@MnO2 core–shell hybrid materials decreased the decomposition temperatures by about 107–112 °C and remarkably increased the exothermic heat to 1311–1452 J g−1. To the best of our knowledge, this is the first 3D hierarchical Co3O4@MnO2 core–shell hybrid material series developed in situ and used for the energy applications of DSSCs and AP decomposition. These results provide a simple and effective strategy for designing new types of 3D hierarchical hybrid materials towards high catalytic activity in energy applications.

Zhengzhou is one of the most heavily polluted cities in China. This study collected samples of PM

Drug-induced kidney injury (DIKI) is a significant contributor of both acute and chronic kidney injury and remains a major concern in drug development and clinical care. However, current clinical diagnostic methods often fail to accurately and timely detect nephrotoxicity. This study reports the development of activatable molecular urinary reporters (MURs) that are able to specifically detect urinary biomarkers including γ-glutamyl transferase (GGT), alanine aminopeptidase (AAP), and N-acetyl-β-d-glucosaminidase (NAG). By virtue of their discrete absorption and emission properties, the mixture of MURs can serve as a cocktail sensor for multiplex optical urinalysis in the mouse models of drug-induced acute kidney injury (AKI) and chronic kidney disease (CKD). The MURs cocktail not only detects nephrotoxicity earlier than the tested clinical diagnostic methods in drug-induced AKI and CKD mice models, but also possesses a higher diagnostic accuracy. Therefore, MURs hold great promise for detection of kidney function in both preclinical drug screening and clinical settings. Ministry of Education (MOE) Nanyang Technological University K.P. thanks the Nanyang Technological University (Start-Up grant: M4081627), Singapore Ministry of Education Academic Research Fund Tier 1 (2017-T1-002-134, RG147/17; 2019-T1-002-045, and RG125/19), and Academic Research Fund Tier 2 (MOE2018-T2-2-042) for financial support.

Abnormal scarring is a hyper-proliferative wound healing disorder, which causes itch, pain, psychological distress, and even limiting limb mobility. Unfortunately, no satisfactory treatment exists to date. Drug screening identifies suitable drugs or drug combinations that inhibit abnormal scarring from a large selection of candidates. However, current techniques are often laborious and technically complex. Herein, we adopt a near-infrared fluorescence probe (FNP1) for fibroblast activation protein (FAP)α, a biomarker overexpressed in skin fibroblasts derived from abnormal scars, to rapidly assess (30 min) drug candidates for the treatment. FNP1 has high sensitivity, even detecting FAPα up-regulation with as little as 0.016 ng/mL TGFβ1, 125-fold lower than typical culture concentrations. The identified drug candidates (RepSox and Thiazovivin) show similar potent anti-scarring activity as the existing anti-scarring compounds and further suppress the expression of other scar biomarkers including connective tissue growth factor (CTGF), alpha-smooth muscle actin (α-SMA), and collagen type 1 (COL1A1).

Abnormal levels of biothiols such as cysteine (Cys) and homocysteine (Hcy) are associated with many pathological diseases. However, most fluorescence probes for biothiols sensing rely on visible fluorescence, which are not optimized for in vivo imaging because of the shallow tissue penetration. We herein synthesize a hydrophobic oligo(phenylenevinylene) (OPV) based semiconducting oligomer amphiphile that can emit both fluorescence and afterglow luminescence and evaluate its ability for detection of biothiols. Such an amphiphile is used to encapsulate a hydrophobic near-infrared (NIR) dye through π-π stacking and hydrophobic interaction to develop a near-infrared (NIR) fluorescence nanoprobe (OPVN0.2). Because the OPV backbone has the benzaldehyde end groups that can specifically react with biothiols, the fluorescence of OPVN0.2 is enhanced in the presence of biothiols; however, its afterglow luminescence of OPVN0.2 remained nearly the same due to the different luminescence mechanism. Such a nanoprobe permits sensitive detection of biothiols both in vitro and in vivo.

Early detection of skin diseases is imperative for their effective treatment. However, fluorescence molecular probes that allow this are rare. The first activatable near-infrared (NIR) fluorescent molecular probe is reported for sensitive imaging of keloid cells, skin cells from abnormal scar fibrous lesions. As keloid cells have high expression levels of fibroblast activation protein-alpha (FAPα), the probe (FNP1) is designed to have a caged NIR dye and a FAPα-cleavable peptide substrate linked by a self-immolative segment. FNP1 can quickly and specifically turn on its fluorescence at 710 nm by 45-fold in the presence of FAPα, allowing it to effectively recognize keloid cells from normal skin cells. Integration of FNP1 with a simple microneedle-assisted topical application enables sensitive detection of keloid cells in metabolically-active human skin tissue with a theoretical limit of detection down to 20 000 cells. MOE (Min. of Education, S’pore) Accepted version

A simple in situ self-assembly selective synthetic strategy for one-step controllable formation of various three-dimensional (3D) hierarchical Co3O4 micro/nanomaterials with peculiar morphologies, uniform size, and high quality is successfully developed. The morphological control and related impact factors are investigated and clarified in detail. The results further clarify the corresponding mechanisms on the reaction process, product generation, and calcining process as well as the formation of specific morphologies. Furthermore, the superior catalytic properties of these materials are confirmed by two typical Co-based energy applications on the decomposition of an important solid rocket propellant, ammonium perchlorate (AP), and dye-sensitized solar cells (DSSCs). The addition of Co3O4 materials to AP obviously decreases the decomposition temperatures by about 118–140 °C and increases the exothermic heat to a great extent. As the substituted counter electrodes of DSSCs, the 3D hierarchical Co3O4 materi...