Constructing novel red-emitting Ba2Y0.8Eu0.2NbO6:Mn4+ phosphors for multi-type luminescent thermometers and high-security anti-counterfeiting films

To date, luminescent materials have been preferably used for non-contact optical thermometers. In this manner, novel red-emitting Ba₂Y_0.8Eu_0.2NbO₆:Mn⁴⁺ (BYEN:Mn⁴⁺) phosphors were designed for multi-type non-contact luminescent thermometers based on the dual-emission states and temperature-dependent lifetime (TDL) models. In the temperature range of 303–483 K, the sensing sensitivities based on the dual-emission states of (⁵D₀→⁷F₂, ²E_g→⁴A_2g) and (⁵D₀→⁷F₁, ²E_g→⁴A_2g) were estimated. Especially, the maximum absolute sensing sensitivity (S_a) was found to be about 0.1558 K^-1 for the BYEN:0.007Mn⁴⁺ phosphor based on the ⁵D₀→⁷F₁ and ²E_g→⁴A_2g positions. This phosphor also exhibited good relative sensing sensitivity (S_r) (0.0186 K^-1) based on the ⁵D₀→⁷F₂ and ²E_g→⁴A_2g states. Besides, the relative sensing sensitivities (S_R) at ⁵D₀→⁷F₁ and ²E_g→⁴A_2g transitions were estimated to be 0.0034 and 0.0194 K^-1, respectively with the help of the TDL technique. In the light of these results, novel red-emitting Ba₂Y_0.8Eu_0.2NbO₆:Mn⁴⁺ phosphors are expected to be a potentially attractive candidate for applications in multi-type luminescent thermometers. Finally, a novel unique polydimethylsiloxane film exhibiting tricolor-luminescent emissions was introduced and further suggested for high-security anti-counterfeiting.     

基于Mn掺杂ZnS量子点的室温磷光传感应用的研究进展

与一般有机染料分子相比,半导体材料量子点具有优异的光学性能,在多个领域得到了广泛的应用.量子点具有窄而对称且可调的发射波长、宽激发强吸收、抗光漂白能力强以及水溶性好等诸多优势,引起了研究者广泛关注.为了增加量子点的斯托克斯位移从而很好地避免量子点的自猝灭现象,引入掺杂物是一种很有效的方式.掺杂量子点不仅保留了量子点原有的优点,而且还赋予量子点额外的优异性能.如Mn掺杂ZnS量子点生物相容性好,不含Cd和Hg等有害元素,而且Mn2+的加入使其具有优异的室温磷光特性.磷光检测能很好地避开生物背景荧光的干扰,使得Mn掺杂ZnS量子点能够广泛应用于磷光生物分析.本文综述了Mn掺杂ZnS量子点在室温磷光分析中的研究进展,着重介绍了几种具有启发意义的设计策略,包括其发光机理以及应用于离子、分子以及生物大分子等的检测.     

基于稀土离子介导石墨烯量子点荧光开关的凝血酶生物传感器

稀土离子(Er3+)可与荧光石墨烯量子点(GQDs)表面的含氧基团发生配位,在Er3+介导下形成高配位数的GQDs/Er3+配合物,引起GQDs聚集而使其荧光减弱.凝血酶(Tb)中的氮和氧等原子可与Er3+发生配位作用,从而与GQDs竞争结合Er3+,减弱了GQDs与Er3+的作用而使其荧光恢复.通过检测GQDs的荧光即可实现对Tb活性的高灵敏分析,构建了基于Er3+介导GQDs荧光开关的Tb传感方法,采用透射电镜、原子力显微镜、红外吸收光谱以及荧光光谱等对传感机理进行了研究.本方法对Tb的检出限低至0.049 nmol/L,其它蛋白质对Tb检测无明显干扰,实际样品中Tb加标回收率为98.0%~105.3%,相对标准偏差为0.6%~4.2%.     

Recent advances in formaldehyde-responsive fluorescent probes

Formaldehyde is one of the simplest reactive carbonyl species. In view of the harmfulness of formaldehyde in nature and humans, it is of great signifi cance to further elucidate roles and functions of formaldehyde by a noninvasive detection approach. Fluorescent probes have become a popular tool to track and detect formaldehyde in vitro and in vivo, which have attracted more and more interest recently. This review focuses on various reaction mechanisms to design the fluorescent probes for detecting formaldehyde.     

Sensing nanomaterials of wearable glucose sensors

The metabolic disorder of glucose in human body will cause diseases such as diabetes and hyperglycemia.Hence the determination of glucose content is very important in clinic diagnosing.In recent years,researchers have proposed various non-invasive wearable sensors for rapid and real-time glucose monitoring from human body fluids.Unlike those reviews which discussed performances,detection environments or substrates of the wearable glucose sensor,this review focuses on the sensing nanomaterials since they are the key elements of most wearable glucose sensors.The sensing nanomaterials such as carbon,metals,and conductive polymers are summarized in detail.And also the structural characteristics of different sensing nanomaterials and the corresponding wearable glucose sensors are highlighted.Finally,we prospect the future development requirements of sensing nanomaterials for wearable glucose sensors.This review would give some insights to the further development of wearable glucose sensors and the modern medical treatment.     

New insights into the anti-hepatoma mechanism of Alisol G-metal ions complexes based on c-myc DNA

This study investigated the anti-hepatoma molecular mechanism of Alisol G, which is an effective component of the Chinese medicine Alisma orientalis, in the presence of metal ions Cu²⁺ and Fe³⁺ based on c-myc DNA. Here, a combination of Alisol G and metal ions (Cu²⁺, Fe³⁺) to augment anti-hepatoma efficiencies of Alisol G has been identified by methyl thiazolyl tetrazolium (MTT) assay. Network pharmacology revealed that c-myc DNA was the potential target of Alisol G with respect to its anti-hepatoma effects. By performing multi-spectroscopic analyses, we showed that the interaction of Alisol G with c-myc DNA was a process of static quenching. The binding constants and thermodynamic constants indicated that a 1:1 complex was formed between Alisol G and c-myc DNA. Moreover, metal ions strengthened the interaction between Alisol G and c-myc DNA. Molecular docking and molecular dynamics simulation further unveiled that the higher binding affinity between Alisol G-Fe³⁺ complex and c-myc DNA as compared to Alisol G-Cu²⁺ complex. This probably resulted from the polarization of metal ions and the structural flexion of Alisol G. The C22-O31-H76 and C18-O32-H77 of Alisol G were key groups in the interaction with c-myc DNA. Addition of metal ion, had greatly changed the c-myc DNA-binding domain of Alisol G while didn’t affect the kinetic stability of the interaction, thus facilitating the insertion of Alisol G into c-myc DNA A-T base pair. Importantly, the DG113 of c-myc DNA was important for its binding to metal ions. Together, our findings suggested that Alisol G in combination with metal ions may be an efficient and promising option for the treatment of liver cancer.     

Effect of purified fractions from cell culture supernate of high‐density pre‐B acute lymphoblastic leukemia cells (ALL3) on the growth of ALL3 cells at low density

The mechanisms underlying the aberrant growth and interactions between cells are not understood very well. The pre‐B acute lymphoblastic leukemia cells directly obtained from an adult patient grow very poorly or do not grow at all at low density (LD), but grow better at high starting cell density (HD). We found that the LD ALL3 cells can be stimulated to grow in the presence of diffusible, soluble factors secreted by ALL3 cells themselves growing at high starting cell density. We then developed a biochemical purification procedure that allowed us to purify the factor(s) with stimulatory activity and analyzed them by nanoliquid chromatography‐tandem mass spectrometry (nanoLC‐MS/MS). Using nanoLC‐MS/MS we have identified several proteins which were further processed using various bioinformatics tools. This resulted in eight protein candidates which might be responsible for the growth activity on non‐growing LD ALL3 cells and their involvement in the stimulatory activity are discussed.     

Modulation of Quorum Sensing in a Gram‐Positive Pathogen by Linear Molecularly Imprinted Polymers with Anti‐infective Properties

We describe the development, characterization, and biological testing of a new type of linear molecularly imprinted polymer (LMIP) designed to act as an anti‐infective by blocking the quorum sensing (QS) mechanism and so abrogating the virulence of the pathogen Streptococcus pneumoniae . The LMIP is prepared (polymerized) in presence of a template molecule, but unlike in traditional molecular imprinting approaches, no cross‐linker is used. This results in soluble low‐molecular‐weight oligomers that can act as a therapeutic agent in vitro and in vivo. The LMIP was characterized by mass spectrometry to determine its monomer composition. Fragments identified were then aligned along the peptide template by computer modeling to predict the possible monomer sequence of the LMIP. These findings provide a proof of principle that LMIPs can be used to block QS, thus setting the stage for the development of LMIPs a novel drug‐discovery platform and class of materials to target Gram‐positive pathogens.     

Facile Synthesis of Metallosalphen-Based 2D Conductive Metal-Organic Frameworks for NO2 Sensing: Metal Coordination Induced Planarization

As an emerging class of promising porous materials, the development of two-dimensional conductive metal organic frameworks (2D c-MOFs) is hampered by the few categories and tedious synthesis of the specific ligands. Herein, we developed a nonplanar hexahydroxyl-functionalized Salphen ligand (6OH-Salphen) through a facile two-step synthesis, which was further applied to construct layered 2D c-MOFs through in situ one pot synthesis based on the synergistic metal binding effect of the N₂O₂ pocket of Salphen. Interestingly, the C_2v-symmetry of ligand endows Cu-Salphen-MOF with periodically heterogeneous pore structures. Benefitting from the higher metal density and shorter in-plane metal-metal distance, Cu-Salphen-MOF showcased excellent NO₂ sensing performance with good sensitivity, selectivity and reversibility. The current work opens up a new avenue to construct 2D c-MOF directly from nonplanar ligands, which greatly simplifies the synthesis and provides new possibilities for preparing different topological 2D c-MOF based functional materials.     

A Humidity-Induced Large Electronic Conductivity Change of 107 on a Metal-Organic Framework for Highly Sensitive Water Detection

The electronic conductivity (EC) of metal–organic frameworks (MOFs) is sensitive to strongly oxidizing guest molecules. Water is a relatively mild species, however, the effect of H₂O on the EC of MOFs is rarely reported. We explored the effect of H₂O on the EC in the MOFs (NH₂)₂-MIL-125 and its derivatives with experimental and theoretical investigations. Unexpectedly, a large EC increase of 10⁷ on H₂SO₄@(NH₂)₂-MIL-125 by H₂O was observed. Brønsted acid–base pairs formed with the −NH₂ groups, and H₂SO₄ played an important role in promoting the charge transfer from H₂O to the MOF. Based on H₂SO₄@(NH₂)₂-MIL-125, a high-performance chemiresistive humidity sensor was developed with the highest sensitivity, broadest detection range, and lowest limit of detection amongst all reported sensing materials to date. This work not only demonstrated that H₂O can remarkably influence the EC of MOFs, but it also revealed that post-modification of the structure of MOFs could enhance the influence of the guest molecule on their EC to design high-performance sensing materials.