Latest ArticlesCarbon dots (CDs), as a new member of carbon nanostructures, have been widely applied in extensive fields due to their exceptional physicochemical properties. While, the emissions of most reported CDs are located in the blue to green range under the excitation of ultraviolet or blue light, which severely limits their practical applications, especially in photovoltaic and biological fields. Studies that focused on synthesizing CDs with long-wavelength (red to near-infrared) emission/excitation features (simply named L-w CDs) and exploring their potential applications have been frequently reported in recent years. In this review, we analyzed the key influence factors for the synthesis of CDs with long wavelength and multicolor (containing long wavelength) emissive properties, discussed possible fluorescence mechanism, and summarized their applications in sensing and cancer theranostics. Finally, the existing challenges and potential opportunities of L-w CDs are presented.
Evaluating the correlation between hypoxia inducible factor 1 (HIF-1) and nitric oxide (NO) generated under hypoxia is of great significance. In this work, we developed a fluorescent probe for the monitor of HIF-1 activity influenced by NO under hypoxia in hepatoma cells with dual-targeting for hepatocyte and lipid droplet (LD). The probe shows excellent selectivity to NO and high sensitivity with 6000-fold fluorescence enhancement. Live cell imaging experiments revealed the probe's capability of imaging exogenous and endogenous NO with specific in LDs of HepG2 cells. For cells under hypoxia, HIF-1 induced LD level is observed to correlate with NO level. This work provides the in-situ visualization of NO-dependent HIF-1 upregulation through LD accumulation.
Cancer is a serious threat to humans due to its high mortality. The efforts to fully understand cancer and to fight against it have never been stopped. The traditional therapies, such as surgery, radiotherapy and chemotherapy, are useful but cannot meet the increasing demands of patients. As such, novel approaches against cancer are urgently required. It has been found that the acidic tumor microenvironment plays important roles in promoting the cancer progression. In recent years, sodium bicarbonate (NaHCO3), a simple inorganic salt, has been found to be able to reverse the pH of tumor microenvironment and inhibit the invasion, metastasis, immune evasion, drug resistance and hypoxia of tumor cells. Thus, NaHCO3-based therapy is a potential approach for the treatment of cancer, and the related studies have been increasingly reported. Herein, we aim to provide a comprehensive understanding of the acidic tumor microenvironment and summarize the applications and mechanisms of NaHCO3 in cancer therapy. The combination of NaHCO3 with chemotherapy, immunotherapy or nanoparticles systems is discussed. In addition, the concerns of NaHCO3 in clinical use and the potential ways to use NaHCO3 for cancer therapy are also discussed.
The photocatalytic nitrogen reduction reaction (NRR) has mild reaction conditions and only requires sunlight energy as a driving force to replace the traditional ammonia synthesis method. We herein investigate the catalytic activity and selectivity on Penta-B2C for NRR by using density functional theory calculations. Penta-B2C is a semiconductor with an indirect bandgap (2.328 eV) and is kinetically stable based on molecular dynamic simulations. The optical absorption spectrum of Penta-B2C is achieved in the ultraviolet and visible range. Effective light absorption is more conducive to generate photo-excited electrons and improving photocatalytic performances. Rich B atoms as activation sites in Penta-B2C facilitate capturing N2. The activated N2 molecule prefers the side-on adsorption configuration on Penta-B2C, which facilitates the subsequent reduction reaction. Among considered NRR mechanisms on Penta-B2C, the best pathway prefers the enzymatic mechanism, only required a low onset potential of 0.23 V. The hydrogen evolution reaction is inhibited when the hydrogen adsorption concentration is increased or N2 molecules first occupy the adsorption sites. Our results indicate Penta-B2C is a highly reactive and selective photocatalyst for NRR. Our work provides theoretical insights into the experiments and has guiding significance to synthesize efficient NRR photocatalysts.
Developing large-scale electrocatalysts using molecular complexes for the oxygen evolution reaction (OER) is of great importance. Herein, four cobalt porphyrins and corroles are deposited on electrode substrates using a simple and fast electropolymerization method. Our results showed that Co-1-P@CC, formed by electropolymerizing Co tetrakis(p-N-pyrrolylphenyl)porphyrin (Co-1-P) on carbon cloth (CC), is the most active OER catalyst in the examined Co porphyrins and corroles in alkaline aqueous solutions by displaying an onset overpotential of 380 mV. Long-term electrolysis tests confirmed the stability of these electropolymerized films by functioning as OER electrocatalysts.
Diabetes is one of the most disturbing chronic diseases in the world. The improvement of treatment efficiency brought by self-monitoring of blood glucose can relieve symptoms and reduce complications, which is considered as the gold standard of diabetes diagnosis and nursing. Compared to the traditional finger pricking measurement with painful and discontinuous processes, continuous blood glucose monitoring (CGM) presents superior advantages in wearable and continuous assessment of blood glucose levels. However, widely used implantable CGM systems at present require implantation operation and are highly invasive, so it is hard to be accepted by users. Except for the blood, available fluids in humans, such as interstitial fluid (ISF), sweat, tears and saliva, also contain glucose associated with blood sugar and can be extracted more easily. Therefore, these more accessible fluids are expected to realize minimized traumatic blood glucose monitoring. This review introduces the latest development of wearable minimally-/non-invasive CGM device, focusing on the types of blood substitute biological fluid and suitable monitoring approaches. We also analysis the merits and drawbacks of each method, and discuss the properties such as sensitivity, stability and convenience of each meter. Beyond highlighting recent key work in this field, we discuss the future development trend of wearable minimally-/non-invasive glucose meters.
Carbene transfer reactions play an important role in the field of organic synthesis because of their ability to construct a variety of molecules. Herein, we reported on blue light-induced cyclopropenizations of N-tosylhydrazones in water, which avoids the use of expensive metal-based catalysts and toxic organic solvents. This metal-free and operationally simple methodology enable highly efficient cyclopropenizations, X-H insertion reactions, and cyclopropanation under mild reaction conditions.
Supercapacitors (SCs) with high power density and long cycling span life are demanding energy storage devices that will be an attractive power solution to modern electronic and electrical applications. Numerous theoretical and experimental works have been devoted to exploring various possibilities to increase the functionality and the specific capacitance of electrodes for SCs. Non-carbon two-dimensional (2D) materials have been considered as encouraging electrode candidates for their chemical and physical advantages such as tunable surface chemistry, high electronic conductivity, large mechanical strength, more active sites, and dual non-faradaic and faradaic electrochemical performances. Besides, these 2D materials also play particular roles in constructing highway channels for fast ion diffusion. This concise review summarizes cutting-edge progress of some representative 2D non-carbon materials for the aqueous electrolyte-based SCs, including transition metal oxides (TMOs), transition metal hydroxides (TMHs), transition metal chalcogenides (TMCs), MXenes, metal-organic frameworks (MOFs) and some emerging materials. Different synthetic methods, effective structural designs and corresponding electrochemical performances are reviewed in detail. And we finally present a detailed discussion of the current intractable challenges and technical bottlenecks, and highlight future directions and opportunities for the development of next-generation high-performance energy storage devices.
We report a series of highly stable metallophthalocyanine-based covalent organic frameworks (MPc-dx-COFs) linked by robust 1, 4-dioxin bonds constructed through nucleophilic aromatic substitution (SNAr) reaction. The chemical structures and crystallinity of the COFs largely remain unchanged even after treating with boiling water (90 ℃), concentrated acids (12 mol/L HCl) or bases (12 mol/L NaOH), oxidizing (30% H2O2) or reducing agents (1 mol/L NaBH4) for three days due to their stable M-Pc building blocks and resilient dioxin linkers. With metallated phthalocyanine active sites regularly arranged in the stable framework structures, MPc-dx-COFs can be directly used as efficient electrocatalysts for the oxygen reduction reaction (ORR) without pyrolysis treatment that has commonly been used in previous studies.
Drug resistance remains to be a serious problem with type I human immunodeficiency virus (HIV-1) non-nucleoside reverse transcriptase inhibitors (NNRTIs). A series of novel boronic acid-containing diarylpyrimidine (DAPY) derivatives were designed via bioisosterism and scaffold-hopping strategies, taking advantage of the ability of a boronic acid group to form multiple hydrogen bonds. The target compounds were synthesized and evaluated for their anti-HIV activities and cytotoxicity in MT-4 cells. Compound 10j yielded the most potent activity and turned out to be a single-digit nanomolar inhibitor towards the HIV-1 IIIB [wild-type (WT) strain], L100I and K103N strains, with 50% effective concentration (EC50) values of 7.19–9.85 nmol/L. Moreover, 10j inhibited the double-mutant strain RES056 with an EC50 value of 77.9 nmol/L, which was 3.3-more potent than that of EFV (EC50 = 260 nmol/L) and comparable to that of ETR (EC50 = 32.2 nmol/L). 10j acted like classical NNRTIs with high affinity for WT HIV-1 reverse transcriptase (RT) with 50% inhibition concentration (IC50) value of 0.1837 μmol/L. Furthermore, molecular dynamics simulation indicated that 10j was proposed as a promising molecule for fighting against HIV-1 infection through inhibiting RT activity. Overall, the results demonstrated that 10j could serve as a lead molecule for further modification to address virus-drug resistance.