Chirality of inorganic nanoparticles (NPs) is an emerging and hot topic in nanoresearch in the past several years. Many novel and interesting properties of chiral NPs have been explored and studied, ...which highlight their importance in both fundamental research and potential applications. This review summarizes recent progress in the study of origins, optical properties and bioapplications of chiral NPs, and future developments in this research area are also discussed.
We experimentally studied the air–water pressure drop characteristics with inner diameters of 20 mm under stable and transverse vibration conditions in the horizontal circular channel. We ...experimented with the status of the gas-phase conversion flow velocity Jg at 0.1–20 m/s, and the liquid-phase conversion flow velocity Jw at 0.1–3.0 m/s. In this paper, we discuss the effect of flow velocity, amplitude, and frequency on the transverse vibration pressure drops. With increasing frequency and amplitude, the vibration performance of pressure drops become more intense. Thus, with increasing frequency and amplitude, the frictional pressure drop increases. Moreover, the frictional pressure drop increases linearly with the increasing flow velocity. We compared the experimental results of air–water pressure drop with the calculated results of previous empirical correlations. Based on Chisholm-C correlation, we obtained a modified correlation for factor C in horizontal channels under transverse vibration conditions. The new correlation considers the effect of channel confinement number, amplitude, frequency, and vapor quality. The new correlation has relatively good prediction results for the experiments, and the mean absolute deviation is 8.2%.
In this paper, we present a simple strategy to fabricate a sensitive fluorescence microfluidic sensor based on quantum dots (QDs) aerogel and acetylcholinesterase enzyme (AChE) for organophosphate ...pesticides (OPs) detection The detection is based on the change of fluorescence intensity of QDs aerogel, which will be partly quenched as a consequence of the hydrolytic reaction of acetylthiocholine (ATCh) catalyzed by the AChE, and then the fluorescence of QDs aerogel is recovered due to decreasing of the enzymatic activity in the presence of OPs. The QDs-AChE aerogel based microfluidic arrays sensor provided good sensitivity for rapid detection of OPs with a detection limit of 0.38 pM, while the detection range is from 10−5 to 10−12 M. Due to the result of random orientations of AChE in the 3D porous aerogel nano-structure, the sensor presents similar calibration curves to difference pesticides, which promises the ability of the sensor to monitor total OPs of mixture. This determination sensor shows a low detection limit, wide linear range, and highly accurate determination of total OPs and carbamate content. Finally, we show the proposed sensor can be used to monitor of simple OPs and mixture in spiked fruit samples. This novel QDs-AChE aerogel sensor has an extremely high sensitivity and large detection range, it is a promising tool for accurate, rapid and cost-effective detection of various OP residues on agricultural products.
•A fluorescence microfluidic arrays sensor based on quantum dots aerogel and enzyme was fabricated.•Sensitive and rapid detection of OPs with a detection time below 20 min and detection limit of 0.4 ng mL−1•The sensor promise the ability of the sensor to monitor total OPs of mixture.•Simple OPs and mixture in spiked fruit samples were detected by our sensor.
The manipulation of the chirality and corresponding optical activity in the visible–near-infrared (NIR) light region is significant to realize applications in the fields of chemical sensing, ...enantioselective separation, chiral nanocatalysis, and optical devices. We studied the plasmon-induced circular dichroism (CD) response by one-dimensional (1D) assembly of cysteine (CYS) and gold nanorods (GNRs). Typically, GNRs can form end-to-end assembly through the electrostatic attraction of CYS molecules preferentially attached on the ends of different GNRs. CD responses are observed at both the UV and visible–NIR light region in the 1D assembly, which are assigned to the CYS molecules and the GNRs, respectively. In addition, the wavelength of the CD responses can be manipulated from 550 nm to more than 900 nm through altering the aspect ratios of GNRs in 1D assembly. Anisotropic enhancement of optical activity is discovered, suggesting that the enhancement of the longitudinal localized surface plasmon resonance (LSPR) peak of GNRs in the CD response is much more apparent than that of the transverse LSPR. The CD responses of individual CYS-attached GNRs and CYS-assembled gold nanoparticles (GNPs) substantiate that the form of assembly and the shape of building blocks are significant not only for the intensity but for the line shape of the CD signals.
Abstract
How soft corona, the protein corona’s outer layer, contributes to biological identity of nanomaterials is largely because capturing protein composition of the soft corona in situ remains ...challenging. We herein develop an in situ Fishing method that can monitor the dynamic formation of protein corona on ultra-small chiral Cu
2
S nanoparticles (NPs) allowing us to directly separate and identify the corona protein composition. Our method detects spatiotemporal processes in the evolution of hard and soft coronas on chiral NPs, revealing subtle differences in NP − protein interactions even within several minutes. This study highlights the importance of in situ and dynamic analysis of soft/hard corona, provides insights into the role of soft corona in mediating biological responses of NPs, and offers a universal strategy to characterize soft corona to guide the rational design of biomedical nanomaterials.
It is observed in this study that the chirality of cysteine stabilizers has a distinct effect on both the growth kinetics and the optical properties of CdTe nanocrystals synthesized in aqueous ...solution. The effect was studied by circular dichroism spectroscopy, temporal UV−vis spectroscopy, photoluminescence spectroscopy, and several other microscopy and spectroscopic techniques including atomic modeling. Detailed analysis of the entirety of experimental and theoretical data led to the hypothesis that the atomic origin of chiral sites in nanocrystals is topologically similar to that in organic compounds. Since atoms in CdTe nanocrystals are arranged as tetrahedrons, chirality can occur when all four atomic positions have chemical differences. This can happen in apexes of nanocrystals, which are the most susceptible to chemical modification and substitution. Quantum mechanical calculations reveal that the thermodynamically preferred configuration of CdTe nanocrystals is S type when the stabilizer is d-cysteine and R type when l-cysteine is used as a stabilizer, which correlates well with the experimental kinetics of particle growth. These findings help clarify the nature of chirality in inorganic nanomaterials, the methods of selective production of optical isomers of nanocrystals, the influence of chiral biomolecules on the nanoscale crystallization, and practical perspectives of chiral nanomaterials for optics and medicine.
Chiral surface is a critical mediator that significantly impacts interaction with biological systems on regulating cell behavior. To better understand how the properties of interfacial Chirality ...affect cell behavior and address the limitations of chiral materials for biomedical applications, in this review, we mainly focus on the recent developments of chiral bio-interfaces for the controllable and accurate guidance of chiral biomedical phenomena. In particular, we will discuss how cells or organisms sense and respond to the chiral stimulus, as well as the chirality mediating cell fate, tissue repair, and organism immune response will be reviewed. In addition, the biological applications of chirality, such as drug delivery, antibacterial, antivirus and antitumor activities, and biological signal detection, will also be reviewed. Finally, the challenges of chiral bio-interfaces for controlling biological response and the further application of interface chirality materials for biomedical will be discussed.
Choose your poison: Chiral CdTe quantum dots (QDs) coated with L‐ or D‐glutathione (GSH) stabilizers exhibit differences in cytotoxicity although they have identical composition and size. D‐GSH‐QDs ...are less cytotoxic than L‐GSH‐QDs. The ability of QDs to induce cell death is correlated with their ability to induce autophagy, which is chirality‐dependent (see picture).
The optical transducer of CdTe semiconductor quantum dots (QDs) has been integrated with acetylcholinesterase enzyme (AChE) by the layer-by-layer (LbL) assembly technique, resulting in a highly ...sensitive biosensor for detection of organophosphorus pesticides (OPs) in vegetables and fruits based on enzyme inhibition mechanism. The detection limits of the proposed biosensors are as low as 1.05×10−11 M for paraoxon and 4.47×10−12 M for parathion, which are significantly better than those of the conventional GC/MS methods or amperometric biosensors (0.5nM). These biosensors are used for quick determination of low concentrations of OPs in real vegetable and fruit samples and exhibit satisfactory reproducibility and accuracy. Moreover, the stock stability of the biosensors are very good due to the stabilizing environment for the enzyme in the nanostructures made by LbL technique. Many advantages provided by these biosensors, like fluorescent change recognized by naked eyes and mass production with low cost, will facilitate future development of rapid and high-throughput screening of OPs.
Chiroptical materials found in butterflies, beetles, stomatopod crustaceans, and other creatures are attributed to biocomposites with helical motifs and multiscale hierarchical organization. These ...structurally sophisticated materials self-assemble from primitive nanoscale building blocks, a process that is simpler and more energy efficient than many top-down methods currently used to produce similarly sized three-dimensional materials. Here, we report that molecular-scale chirality of a CdTe nanoparticle surface can be translated to nanoscale helical assemblies, leading to chiroptical activity in the visible electromagnetic range. Chiral CdTe nanoparticles coated with cysteine self-organize around Te cores to produce helical supraparticles. d -/ l -Form of the amino acid determines the dominant left/right helicity of the supraparticles. Coarse-grained molecular dynamics simulations with a helical pair-potential confirm the assembly mechanism and the origin of its enantioselectivity, providing a framework for engineering three-dimensional chiral materials by self-assembly. The helical supraparticles further self-organize into lamellar crystals with liquid crystalline order, demonstrating the possibility of hierarchical organization and with multiple structural motifs and length scales determined by molecular-scale asymmetry of nanoparticle interactions.
PDF