Latest ArticlesThe threat to public health from bacterial infections has led to an urgent need to develop simpler, faster and more reliable bacterial detection methods. In this work, we developed a universal dual-recognition based sandwich fluorescence resonance energy transfer (FRET) sensor by using specific aptamer-modified quantum dots (Aptamer-QDs) as energy donor and lectin concanavalin A (Con A) modified gold nanoparticles (Con A-AuNPs) as energy acceptor to achieve rapid and sensitive detection of Escherichia coli (E. coli) within 0.5 h. In the presence of the target E. coli, the energy donor of Aptamer-QDs and acceptor of Con A-AuNPs were close to each other, causing changes of FRET signals. Based on the constructed FRET sensor, a linear detection range of from 102 cfu/mL to 2 × 108 cfu/mL with the detection limit of 45 cfu/mL for E. coli was achieved. Furthermore, the FRET sensor was applied to detect E. coli in the milk and orange juice with the detection limit of 300 cfu/mL and 200 cfu/mL, respectively and recovery rate from 83.1% to 112.5%. The strategy holds great promise in pathogenic bacteria detection due to its rapid and sensitivity.
In clinic, the combination of intravenous pembrolizumab (PD-1 monoclonal antibody) with oral Lenvatinib (LEN) exhibited an enhanced synergistic benefit for cancer therapy. However, the clinical outcomes were always limited by the problems of inconsistent pharmacokinetic profiles of two drugs, lower drug accumulation in tumor and obvious side effects during the combination therapy. Here, in situ-forming thermosensitive hydrogels based on PLGA-PEG-PLGA triblock copolymers were prepared for local administration of anti-PD1 and LEN (P&L@Gel) to improve therapeutic efficacy and safety. After peritumoral or surgical resection site injection, the significant increased concentrations of both drugs in tumor were observed with the local sustained release of P&L@Gel. In comparison with the group of intraperitoneal anti-PD1 plus oral LEN (P-ip&L-po), significantly higher tumor inhibition efficiency on CT26 tumor models could be obtained in P&L@Gel group, even at the dose of one-eighth of the former, same tumor-inhibition effects could be achieved. The enhanced antitumor efficacy of P&L@Gel group was probably associated with the 2.2 folds of increased level of CD8+ T cells and the polarization of tumor associated macrophage from M2 to M1 along with the increased drug accumulation. Moreover, compared with the obvious side effects of P-ip&L-po group, no significant changes of PLT, ALT and UA in blood, as well as IL-1α and IL-1β in mice paws were observed between P&L@Gel group and untreated group. These results suggested that local administration of anti-PD1 and LEN with thermosensitive hydrogel could offer a potential strategy for tumors or tumor postoperative adjuvant treatment.
1,4-Enyne units are ubiquitous skeletons in biologically active molecules and natural products. Especially, they represent versatile building blocks for abundant downstream derivatizations via controllable modifications of both alkene and alkyne units independently. Recently, great efforts have been made to establish efficient protocols to achieve optically active 1,4-enynes. Considering the enormous application potential of enantioenriched 1,4-enyne units but no related review on this topic has been described, here we aim to provide a comprehensive summary on the catalytic methods established for enantioselective constructions of these intriguing skeletons. According to the reaction types, this review is divided into five parts, including asymmetric allylic substitution, asymmetric propargylic substitution, asymmetric alkynylallylic substitution, asymmetric hydroalkynylation and asymmetric 1,2-addition of alkynes to conjugated imines or ketones.
Nature chooses phosphorylation as a key modification to modulate and program the functions of proteins. Various phosphorylated peptides (PPs) have been widely identified and investigated by biologists, but the possibility that PPs could become a building unit for artificial materials is neglected. Here we report for the first time a supramolecular assembly of PPs with the assistance of dysprosium ions (Dy3+). Dy3+ bridges multiple phosphate groups in double-phosphorylated peptides (di-PPs), and braid these peptide chains into nanofibers. The assembly occurs inside nanochannels and blocks the channels, leading to prominent "ON–OFF" switching in transmembrane ionic current. The di-PPs' assembling process could be dynamically regulated by the addition or deletion of phosphate groups under the control of kinases or phosphatases. This study proves the huge potential of PPs being utilized as materials via self-assembling, which will promote the design of novel bio-inspired artificial materials and devices.
Photoresponsive supramolecular systems have merited extensive attention for their applications in materials science and life science. Here, we synthesized a water-soluble stiff-stilbene molecular photoswitch, exhibiting outstanding photoisomerization reaction between its (E)- and (Z)-configurations upon irradiation at distinct light. The photoswitch can assemble with cucurbit[7]uril (CB[7]) to form a superior fluorescent supramolecular complex (compared to the only guest) with excellent water solubility, which manifested dramatic photoluminescence enhancement caused by restriction of intramolecular rotation and remained good photochromic characteristics. Furthermore, introduction of CB[7] influence photoreaction quantum yield (Φ) of the stiff-stilbene, leading to reduction of ΦE→Z and increase of ΦZ→E of the stiff-stilbene. Importantly, the photoadjustable supramolecular assembly can act as a fluorescence switch, and the phototunable guest further selectively modulate G-quadruplex structure of Tel22 upon light irradiation or with addition of CB[7]. The study provides a new simple way for accurately regulating photochromic properties of molecular switches and developing smart materials with potential applications in controlled modulation of G-quadruplex, targeted biological imaging and so on.
Residual antibiotics in food pose a serious long-term threat to human health. Therefore, an on-site visualization method for antibiotic detection is required. However, the requirements of traditional antibiotic testing methods in terms of operator proficiency and equipment cost hinder the rapid point-of-care-testing detection of suspected samples. Herein, we reported an integrated microfluidic device combining a microfluidic chip containing cruciform valves with immunochromatographic strips for the rapid detection of multiple antibiotics in milk. The rapid qualitative and quantitative analysis of four types of antibiotics (sulfonamides, β-lactams, streptomycin, and tetracyclines) was performed using mobile phone photography and mobile phone application analysis. The detection time was maintained at 10 min. The limits of detection (LODs) for the four antibiotics were 0.15, 0.12, 0.25, and 0.29 ng/mL, respectively, and the selectivity for the different antibiotics was observed even in a highly complex matrix. This device successfully integrated separation and real-time detection onto a chip and might provide a promising perspective for the detection of multiple antibiotics in milk.
Electrochemical reduction of CO2 (CO2RR) to value-added chemicals is an attractive strategy for greenhouse gas mitigation and carbon recycle. Carbon material is one of most promising electrocatalysts but its product selectivity is limited by few modulating approaches for active sites. Herein, the predominant pyridinic N-B sites (accounting for 80% to all N species) are fabricated in hierarchically porous structure of graphene nanoribbons/amorphous carbon. The graphene nanoribbons and porous structure can accelerate electron and ion/gas transport during CO2RR, respectively. This carbon electrocatalyst exhibits excellent selectivity toward CO2 reduction to CH4 with the faradaic efficiency of 68% at -0.50 V vs. RHE. As demonstrated by density functional theory, a proper adsorbed energy of *CO and *CH2O are generated on the pyridinic N-B site resulting into high CH4 selectivity. Therefore, this study provides a novel method to modulate active sites of carbon-based electrocatalyst to obtain high CH4 selectivity.
By considering the exceptional properties of supramolecular, noble metals (NM) and magnetic nanoparticles (NPs), we successfully synthesized a novel magnetic, metals and supramolecular composite. Briefly, the Fe3O4@SiO2 core-shell spheres were first modified with gold (Au) and palladium (Pd) NPs and then with mono-6-thio-β-cyclodextrin (SH-β-CD). The synthesized Fe3O4@SiO2-Au-Pd@SH-β-CD nanocomposite shows a good magnetic response (42.3 emu/g). The nanocomposite showed good performance for the reductive degradation of rhodamine B (RhB) and 4-nitrophenol (4-NP). The calculated rate constant (k) values for the reduction of 4-NP and RhB were 0.062± 0.02 s−1 and 0.027± 0.01 s−1, respectively. The high catalytical performance was supposed to be due to the host-guest interaction of β-CD and also due to the NM synergic effect. The nanocomposite structural and chemical morphology was investigated by various spectroscopic techniques. Furthermore, the catalyst was recycled six times and it maintains morphology, chemical nature, and high magnetic behavior, as demonstrated by FTIR and TEM analysis of the recycled catalyst. These results demonstrate a very efficient, cost-effective, and recyclable catalyst in the field of catalysis technology development.
Derivatives of piperazine, which is one of the most important heterocycles, are often used as linkers to connect active substructures that show promising bioactivities, especially in the field of agrochemicals. From 2000 to 2022, many piperazine-containing compounds were found to exhibit excellent activities against fungi, bacteria, insects, plant viruses, and weeds and have also been used as plant growth regulators. Currently, the development of novel pesticides to prevent the invasion of crop pathogens and ensure the quality and yields of crops is still needed. We herein investigated and summarized the role that piperazine plays in the discovery of pesticides to provide a comprehensive summary of the broad activities of piperazine derivatives in agricultural applications and offer a potential reference for novel pesticide design using piperazine-containing compounds. Moreover, structure–activity relationships (SARs) analyses of bioactive piperazine-containing compounds are also discussed for a deeper understanding.
The design and synthesis of photoactive macrocyclic molecules continue to attract attention because such species play important roles in supramolecular chemistry as well as photoelectronic applications. Donor-acceptor (D-A) conjugated macrocycles are an emerging class of photoactive molecules due to their D-A conjugated structural characteristics and tunable optical properties. In addition, the well-defined cavities in such D-A macrocycles endow them with versatile host-guest properties. In this review, we provide a comprehensive summary of D-A conjugated macrocycle chemistry, detailing recent progress in the area of synthetic methods, optical properties, host-guest chemistry and applications of the underlying chemistry to chemical sensors, bioimaging and photoelectronic devices. Our objective is to provide not only a review of the fundamental findings, but also to outline future research directions where D-A conjugated macrocycles and their constructs may have a role to play.