Search

Rapid and accurate in situ determination of dopamine is of great significance in the study of neurological diseases. In this work, poly (3,4-ethylenedioxythiophene): poly (styrenesulfonic acid) (PEDOT: PSS)/graphene oxide (GO) fibers were fabricated by an effective method based on microfluidic wet spinning technology. The composite microfibers with stratified and dense arrangement were continuously prepared by injecting PEDOT: PSS and GO dispersion solutions into a microfluidic chip. PEDOT: PSS/GO fiber microelectrodes with high electrochemical activity and enhanced electrochemical oxidation activity of dopamine were constructed by controlling the structure composition of the microfibers with varying flow rate. The fabricated fiber microelectrode had a low detection limit (4.56 nM) and wide detection range (0.01–8.0 µM) for dopamine detection with excellent stability, repeatability, and reproducibility. In addition, the PEDOT: PSS/GO fiber microelectrode prepared was successfully used for the detection of dopamine in human serum and PC12 cells. The strategy for the fabrication of multi-component fiber microelectrodes is a new and effective approach for monitoring the intercellular neurotransmitter dopamine and has high potential as an implantable neural microelectrode. [ABSTRACT FROM AUTHOR]

Because of advances in data collection and storage, statistical analysis in modern scientific research and practice now has opportunities to utilize external information such as summary statistics from similar studies. A likelihood approach based on a parametric model assumption has been developed in the literature to utilize external summary information when the populations for the external data and main internal data are assumed to be the same. In this article, we instead consider the generalized estimation equation (GEE) approach for statistical inference, which is semiparametric or nonparametric, and show how to utilize external summary information even when internal and external data populations are not the same. Our approach is coupling the internal data and external summary information to form additional estimation equations and then applying the generalized method of moments (GMM). We show that the proposed GMM estimator is asymptotically normal and, under some conditions, is more efficient than the GEE estimator without using external summary information. Estimators of the asymptotic covariance matrix of the GMM estimators are also proposed. Simulation results are obtained to confirm our theory and quantify the improvements by utilizing external data. An example is also included for illustration. [ABSTRACT FROM AUTHOR]

Lithium is known as the "white petroleum" of the electrification era, and the global demand for lithium grows rapidly with the quick development of new energy industry. The aqueous solutions, such as salt lake brine, underground brine, and seawater, have large lithium reserves, thus this kind of lithium resource has become a research hotspot recently. Compared with other lithium extraction technologies, electro-sorption method shows good prospects for practical applications with advantages in the aspects of efficiency, recovery ratio, cost, and environment. Herein, this review covers recent progress on electro-sorption technology for lithium recovery from aqueous solutions, including the concept illustration, research progress of the applied working electrodes and counter electrodes, and the evaluation indicators of electro-sorption system. Meanwhile, some prospects for the development of this technology are also proposed. We hope this review is beneficial for the construction of high-efficient electrochemical lithium recovery system to achieve an adequate lithium supply in the future. [ABSTRACT FROM AUTHOR]

Isolation and manipulation of single cells play a crucial role in drug screening. However, previously reported single-cell drug screening lacked multiple-dose concentration gradient studies, which limits their ability to predict drug performance accurately. To solve this problem, we constructed a multiconcentration gradient generator in which a Tai Chi-spiral mixer can accelerate solution mixing in a short time and produce a linear concentration gradient. Later, a gradient generator combined with a single-cell capture array was adopted to investigate the effects of single or combined doses of 5-fluorouracil and cisplatin on human hepatoma cells and human breast carcinoma cells (at the single-cell level). The results showed that both drugs were effective in inhibiting the growth of cancer cells, and the combination was more effective for human hepatoma cells. In addition, the relationship between the biomechanical heterogeneity (e.g., deformability and size) of tumor cells and potential drug resistance at the single-cell level was investigated, indicating that small and/or deformable cells were more resistant than large and/or less deformable cells. The device provides a simple and reliable platform for studying the optimal dosage of different drug candidates at the single-cell level and effectively screening single-agent chemotherapy regimens and combination therapies. [ABSTRACT FROM AUTHOR]

Tin bronze was cladded on bare steel and nickel-plated steel to fabricate the tin bronze/steel bimetallic materials. The interfacial microstructures and infiltrated cracks in the bimetallic materials were investigated. As the tin bronze was cladded on the bare steel, metallurgical bonding was achieved, and a transition layer with BCC-Fe structure was generated at the tin bronze/steel interface. Infiltrated cracks originated from the interface and propagated into the interior of the steel along the grain boundaries. The main infiltrated crack had branch infiltrated cracks and most of the infiltrated cracks were less than 100 μm. The composition of infiltrated crack was similar to the tin bronze layer, and the infiltrated crack was composed of α-Cu (Sn) phase and δ-Cu41Sn11 phase. The infiltrated cracks could not deform synchronously with the steel matrix, and infiltrated cracks could evolve into macro cracks under lower stress and strain during the in situ tensile experiment. Cracking occurred not only in the boundary between the tin bronze and steel but also occurred in the interior of the tin bronze. Two kinds of fracture zone existed in the fracture including the ductile fracture zone and brittle fracture zone. As the tin bronze was cladded on the nickel-plated steel, a transition layer with BCC-Fe structure was also generated between the tin bronze and steel. Nickel was enriched at the interface and grain boundaries. The infiltrated cracks were eliminated. The nickel-segregated grain boundary could not evolve into macro crack during the in situ tensile process. [ABSTRACT FROM AUTHOR]

Superamphiphobic surfaces have attracted the attention of researchers because of their broad application prospects. Currently, superamphiphobicity is primarily achieved by minimizing the solid—liquid contact area. Over the past few decades, researchers have primarily focused on using physical deposition methods to construct superamphiphobic surfaces using fine-sized nanoparticles (< 100 nm). However, porous hollow SiO2 particles (PH-SiO2), which are typically large spheres, have a highly hierarchical structure and can provide lower solid—liquid contact fractions than those provided by fine-sized particles. In this study, we used PH-SiO2 as building blocks and combined them with poly (dimethylsiloxane) to construct a mechanically robust coating on fiber by spray-coating. After chemical vapor deposition treatment, the coating exhibited excellent superamphiphobicity and could repel various liquids, covering a wide range of surface tensions (27.4–72.0 mN·m−1). [ABSTRACT FROM AUTHOR]

Glioblastoma multiforme (GBM) is an aggressive brain cancer with a poor prognosis and few treatment options. Here, building on the observation of elevated lactate (LA) in resected GBM, we develop biomimetic therapeutic nanoparticles (NPs) that deliver agents for LA metabolism-based synergistic therapy. Because our self-assembling NPs are encapsulated in membranes derived from glioma cells, they readily penetrate the blood-brain barrier and target GBM through homotypic recognition. After reaching the tumors, lactate oxidase in the NPs converts LA into pyruvic acid (PA) and hydrogen peroxide (H2O2). The PA inhibits cancer cell growth by blocking histones expression and inducing cell-cycle arrest. In parallel, the H2O2 reacts with the delivered bis[2,4,5-trichloro-6-(pentyloxycarbonyl)phenyl] oxalate to release energy, which is used by the co-delivered photosensitizer chlorin e6 for the generation of cytotoxic singlet oxygen to kill glioma cells. Such a synergism ensures strong therapeutic effects against both glioma cell-line derived and patient-derived xenograft models. Targeting cancer-associated metabolism is evolving as a promising approach for cancer therapy. Here, the authors generate cancer cell-membrane encapsulated nanoparticles to induce cell cycle arrest and cytotoxicity in lactate-high cancer cells, reducing tumourigensis in glioblastoma cell-line and patient-derived models. [ABSTRACT FROM AUTHOR]

Due to the strong requirement of keyhole TIG (K-TIG) welding for arc length stability and the advantages of voltage sensing, it is necessary to discuss the relationship between the voltage and arc length. In this paper, based on several groups of experiments, a nonlinear transition point between the relationship of voltage and arc length was found with increasing arc length. Then, to analyze the formation mechanism of the nonlinear transition, a simplified arc physical model was developed. After considering the variations in the welding parameter, the reduction in arc pressure was found to be the main factor leading to a nonlinear relationship, while the shielding gas flow rate is the most effective parameter. This work lays a foundation for better understanding the welding arc and real-time control of arc length by voltage sensing in K-TIG welding. [ABSTRACT FROM AUTHOR]

Riemann surfaces are deformed versions of the complex plane in mathematics. Locally they look like patches of the complex plane, but globally, the topology may deviate from a plane. Nanostructured graphitic carbon materials resembling a Riemann surface with helicoid topology are predicted to have interesting electronic and photonic properties. However, fabrication of such processable and large π-extended nanographene systems has remained a major challenge. Here, we report a bottom-up synthesis of a metal-free carbon nanosolenoid (CNS) material with a low optical bandgap of 1.97 eV. The synthesis procedure is rapid and possible on the gram scale. The helical molecular structure of CNS can be observed by direct low-dose high-resolution imaging, using integrated differential phase contrast scanning transmission electron microscopy. Magnetic susceptibility measurements show paramagnetism with a high spin density for CNS. Such a π-conjugated CNS allows for the detailed study of its physical properties and may form the base of the development of electronic and spintronic devices containing CNS species. Fabrication of large π-conjugated carbon nanosolenoid materials with helicoid topology remains a challenge. Here the authors demonstrate synthesis of a metal-free π-extended carbon nanosolenoid material with a helical structure, exhibiting unique photophysical and magnetic properties. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is a malignancy characterized by a high fatality rate. Increasing evidence indicating that long non-coding RNAs (lncRNAs) play a regulatory role in hepatocellular carcinoma (HCC). Among them, the correlation between LINC02298 and HCC remains unknown. The expression and subcellular localization of LINC02298 in HCC tissues and cell lines were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Furthermore, the correlation between the expression of LINC02298 and clinicopathological features of HCC patients was analyzed. The regulatory effects of LINC02298 in HCC were investigated using colony formation, cell count Kit-8(CCK8), Transwell, EDU, cell cycle and apoptosis analysis. In addition, the expression of EMT-related proteins were detected by western blotting. Dual-luciferase reporter, RT-qPCR and rescue assays were employed to validate the involvement of the LINC02298/miR-28-5p/CCDC6 axis in the progression of HCC. The up-regulation of LINC02298 was observed in hepatocellular carcinoma (HCC) tissues and cells, and it was found to be correlated with a negative prognosis in patients with HCC. Overexpression of LINC02298 enhanced the proliferation, migration, invasion, and induction of Epithelial-Mesenchymal Transition (EMT) while suppressing apoptosis in HCC cells. LINC02298 bind to miR-28-5p to regulate the expression of CCDC6. Inhibition of miR-28-5p saved the inhibitory effect of shLINC02298, and knockdown of CCDC6 also saved the inhibitory effect of miR-28-5p on HCC in vitro and in vivo. LINC02298 regulates the expression of CCDC6 by sponging of miR-28-5p, thereby facilitating the the malignancy and EMT of HCC.The expression of LINC02298 exhibited an elevation in HCC tissues and cell lines. LINC02298 functions as a competing endogenous RNA (ceRNA) by sequestering microRNAs (miRNAs) to modulate the expression of PDLIM5. Furthermore, it has been observed that LINC02298 plays a significant role in enhancing the proliferation, migration, and invasion capabilities of HCC cells, while simultaneously inhibiting apoptosis.Graphical Abstract: Hepatocellular carcinoma (HCC) is a malignancy characterized by a high fatality rate. Increasing evidence indicating that long non-coding RNAs (lncRNAs) play a regulatory role in hepatocellular carcinoma (HCC). Among them, the correlation between LINC02298 and HCC remains unknown. The expression and subcellular localization of LINC02298 in HCC tissues and cell lines were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Furthermore, the correlation between the expression of LINC02298 and clinicopathological features of HCC patients was analyzed. The regulatory effects of LINC02298 in HCC were investigated using colony formation, cell count Kit-8(CCK8), Transwell, EDU, cell cycle and apoptosis analysis. In addition, the expression of EMT-related proteins were detected by western blotting. Dual-luciferase reporter, RT-qPCR and rescue assays were employed to validate the involvement of the LINC02298/miR-28-5p/CCDC6 axis in the progression of HCC. The up-regulation of LINC02298 was observed in hepatocellular carcinoma (HCC) tissues and cells, and it was found to be correlated with a negative prognosis in patients with HCC. Overexpression of LINC02298 enhanced the proliferation, migration, invasion, and induction of Epithelial-Mesenchymal Transition (EMT) while suppressing apoptosis in HCC cells. LINC02298 bind to miR-28-5p to regulate the expression of CCDC6. Inhibition of miR-28-5p saved the inhibitory effect of shLINC02298, and knockdown of CCDC6 also saved the inhibitory effect of miR-28-5p on HCC in vitro and in vivo. LINC02298 regulates the expression of CCDC6 by sponging of miR-28-5p, thereby facilitating the the malignancy and EMT of HCC.The expression of LINC02298 exhibited an elevation in HCC tissues and cell lines. LINC02298 functions as a competing endogenous RNA (ceRNA) by sequestering microRNAs (miRNAs) to modulate the expression of PDLIM5. Furthermore, it has been observed that LINC02298 plays a significant role in enhancing the proliferation, migration, and invasion capabilities of HCC cells, while simultaneously inhibiting apoptosis. [ABSTRACT FROM AUTHOR]

An exceptional phenomenon has been observed that SO2 and NOx in flue gas can be effectively adsorbed over activated carbon with a surprising capacity at cold temperatures with the presence of oxygen. In this study, the adsorption characteristics of NO and SO2 over activated carbon at 80, 20, 0, and − 20 is experimentally investigated. Without the presence of oxygen, adsorption of NO is negligible. In the presence of oxygen, NO can be oxidized to NO2 over activated carbon which leads to the co-adsorption of NO/NO2 within the adsorption bed. Catalytic oxidation of NO over activated carbon can be significantly enhanced at cold temperatures, leading to an extraordinary increase of adsorption capacity of NO. With an initial concentration of NO = 200 ppmv and a space velocity of 5000 h−1, the average specific capacity increases from 3.8 to 169.1 mg/g when the temperature decreases from 80 to – 20 ℃. For NO–O2 co-adsorption, the specific capacity increases along the adsorption bed due to the increasing NO2 concentrations. The adsorption capacity of SO2 is also significantly enhanced at cold temperatures. With an initial concentration of SO2 = 1000 ppmv, the specific capacity increases from 12.9 to 123.1 mg/g when the temperature decreases from 80 to – 20 ℃. A novel low-temperature adsorption (LAS) process is developed to simultaneously remove SO2 and NOx from flue gas with a target of near-zero emission. A pilot-scale testing platform with a flue gas flowrate of 3600 Nm3/h is developed and tested. Emission of both SO2 and NOx is less than 1 ppmv, and the predicted energy penalty is about 3% of the net generation. [ABSTRACT FROM AUTHOR]

As a typical strand displacement–based DNA circuit, the catalytic hairpin assembly (CHA) has the potential to transduce and amplify signals for analytical applications, but little practice has been fulfilled in Luminex-based multiple microRNAs (miRNAs) detection. Here, we proposed a target-fueled CHA-based platform for sensitive and multiple miRNAs detection, by virtue of the multiplex characteristic of the Luminex xMAP platform. The cyclic use of target miRNA, which forms a substantial amount of H1-H2 duplexes, has amplified the fluorescent response to achieve sensitive sensing. Key experimental conditions including hairpin probe concentrations, reaction temperature, and concentration of SA-PE were optimized. Liver tumor–related miRNA-21, miRNA-122, and miRNA-222 could be simultaneously detected with LOD of 2 pM. Overall, the proposed method first combined CHA with the Luminex xMAP system to construct a sensitive sensing platform suitable for multiple miRNAs detection in real sample analysis, which could potentially be applied in biomedical research and clinical diagnosis. [ABSTRACT FROM AUTHOR]

Y., Zhang, Z. & Guo, W. Topological hybrid nodal-loop semimetal in a carbon allotrope constructed by interconnected Riemann surfaces. "The original version of this Article omitted an acknowledgement to the source of Fig. Author Correction: Synthesis of a magnetic -extended carbon nanosolenoid with Riemann surfaces. [Extracted from the article]

A potential novel fumarate reductase gene designated frd1A was isolated by screening a marine metagenomic library through a sequence-based strategy. Sequence analyses indicated that Frd1A and other putative fumarate reductases were closely related. The putative fumarate reductase gene was subcloned into a pETBlue-2 vector and expressed in Escherichia coli Tuner(DE3)pLacІ cells. The recombinant protein was purified to homogeneity. Functional characterization by high-performance liquid chromatography demonstrated that the recombinant Frd1A protein could catalyze the hydrogenation of fumarate to succinate acid. The Frd1A protein displayed an optimal activity at pH 7.0 and 28 °C, which could be stimulated by adding metal ions such as Zn and Mg. The Frd1A enzyme showed a comparable affinity and catalytic efficiency under optimal reaction conditions: k =0.227 mmol/L, v= 29.9 U/mg, and k/ k=5.44 × 10 per mol/s. The identification of Frd1A protein underscores the potential of marine metagenome screening for novel biomolecules. [ABSTRACT FROM AUTHOR]

A pneumatic microchannel network (PμCN) fabrication method for producing a three-dimensional microvascular system in an integrated microfluidic device is described. The spatial dynamics of the PμCN profile is systematically characterized and quantitatively analyzed. A microvessel network-embedded hydrogel scaffold is constructed using in situ pneumatic actuation of the PμCN and collagen polymerization. The endothelium-containing microvasculature, which has high cell viability and typical vascular features, was formed by seeding and cultivating human umbilical vein endothelial cells (HUVEC-C). Furthermore, a quantitative investigation of the adhesive interactions between breast cancer cells and endothelial cells was performed with vascular tissue-mimicry in the hydrogel-supported endothelial network using human breast cancer cells (MDA-MB-231) and HUVEC-C cells. The results show signal-promoted and region-preferred adhesion of cancer cells in the established microvascular network. The PμCN can be applied as an active microfluidic molding component for convenient and robust reproduction of microvasculature in vitro. PμCN application can be valuable in monitoring and investigating blood vessel-involved physiologic/pathologic processes. Moreover, this method will facilitate controllable parenchymal tissue organization and construction for tissue engineering as well as subsequent applications for clinical medicine. [ABSTRACT FROM AUTHOR]

The methodical development of cell biology has resulted in significant advancements in the study of breast tumors. However, the dynamic investigation of the self-seeding process remains largely out of reach. In the present study, we describe a microvalve and liquid membrane double-controlled integrated microfluidic device that provides for the versatile assessment of breast tumor cell invasion dynamics. The liquid membrane formation was first optimized to obtain a high level of control, and was then applied to different types of homotypic and heterotypic cell seeding with precise selective positioning for monoculture and coculture. Using this device, the interaction between breast cancer cells MDA231-LM2 and MDA-MB231 was successfully observed to investigate self-seeding dynamics, including migration, infiltration, and coexistence. The results quantitatively demonstrate the mutual signal-induced attraction between MDA-MB231 and MDA231-LM2 cells, as well as the progressive infiltration of MDA231-LM2 cells into the MDA-MB231 cell population. These results are valuable in the development of spatiotemporal-controlled microfluidic systems and to many microscale-based biological and diagnostic studies involving cell growth, cell differentiation, cell interaction, and cell signal. [ABSTRACT FROM AUTHOR]

Ethanol consumption is associated with the risk of breast cancer progression; however, the mechanism of relationship has not yet been fully explained. Research on breast cancer cell migration after ethanol stimulation may give hope for a better understanding of the disease and oncotherapy. Conventional cell migration assays such as Boyden chamber and wound-healing assays are easy to conduct for this purpose; however, these assays have inherent limitations. In this study, we quantified the effect of ethanol on MCF-7 hunam breast cancer cells using a microfluidics-based wound-healing assay. Wounds were prepared by partially digesting a confluent cell sheet using parallel laminar flows in the presence of protease trypsin. The cells at the leading edge of the wound remained intact. Cell image analysis indicates that all the cells cultured in the microdevice took on a good morphology and monolayer growth status. Cell viability assay demonstrates that cell viability decreased with the increase in ethanol concentration and treatment time. For 0, 22, 43, and 65 mmol/l of ethanol, cell viability after being cultured for 24 h was 100%, 99.6%, 99.4%, and 98.4%, respectively. Studying MCF-7 human breast cancer cell migration when treated with different ethanol concentrations revealed that the cell migration distance is directly proportional with ethanol concentration. After being cultured for 24 h at 37°C and 5% CO, the maximal cell migration distance was 231, 283, and 332 μm for 22, 43, and 65 mmol/l ethanol, respectively; all results were higher than the blank test (i.e., ethanol-free test, 218 μm). These findings will be beneficial in developing microfluidic device applications for future research on breast tumor therapy in a biomimetic microenvironment and for developing new methods for breast cancer therapy. [ABSTRACT FROM AUTHOR]

Microfluidic systems provide a powerful platform for biological analysis and have been applied in many disciplines. However, few efforts have been devoted to plant cell study. In this article, an optimized culture of tobacco mesophyll protoplasts and their first polyethylene glycol-induced fusion in a microfluidic device are presented. Culture medium optimization and dynamics of protoplast growth including size change, organelle motion, and cell mass formation were also investigated microscopically in real-time. On-chip protoplast culture showed that the first division percentage of tobacco mesophyll protoplasts could be improved as high as up to 85.6% in 5 days using NT1 medium, and the percentage of small cell mass formation was more than 48.0% in 10 days. Meanwhile, chemical-induced fusion of tobacco mesophyll protoplasts was realized in 3-5 min and a 28.8% fusion rate was obtained, which was similar to the conventional fusion in a macro-scale environment. These results will be helpful for the development of microfluidics-based studies on manipulation and analysis of plant cells in a miniaturized environment, including cell growth and differentiation, gene isolation, and cloning. [ABSTRACT FROM AUTHOR]

Despite progress in research and treatment, the prognosis for patients with gliomas remains relatively dismal. As such, develop a new in vitro model is fast becoming a necessary step in efforts to improve research on malignant gliomas. Microfluidics, a potentially effective tool, has been increasingly applied in neuroscience and oncology studies. However, gliomas, the most common primary brain tumours, have not yet been treated with this application. In the current study, we developed a glioma-related research method using microfluidics. After successfully culturing rat C6 glioma cells for up to 7 days in a microfluidic device, we monitored cellular responses to the anticancer drug, colchicines, after which we analysed cell viability using propidium iodide (PI) staining. We recorded temporal changes in cell morphology at various concentrations of colchicine using an inverted microscope. Results show that the number of injured/dead cancer cells and morphological changes increased relative to the drug’s concentration and treatment frequency. These findings will be helpful in developing microfluidic device applications for future research on brain tumour therapy (for malignant gliomas and other types of tumours), for conducting cytotoxicity research in a biomimetic microenvironment, for developing glioma-related anticancer drugs, and for developing glial cell-based biosensors for glioma detection. [ABSTRACT FROM AUTHOR]

Six metal(II) complexes with quercetin ML2 · nH2O [L = quercetin (3-OH group deprotonated); M = Mn, Co, Ni, Cu, Zn, and Pb; n = 2 or 3] have been prepared and characterized by elemental analysis, complexometric titration, thermal analysis, conductivity, i.r., u.v., 1H-n.m.r. and fluorescence spectral techniques as well as by cyclic voltammetry. The antioxidative and anti-tumour activities of quercetin · 2H2O and the complexes were tested by both the MTT and SRB methods. The results show that the suppression ratios of the complexes against the tested tumour cells are superior to quercetin · 2H2O. The effect of ZnL2 · 3H2O reacting with calf thymus DNA was studied by fluorescence methods. The Zn-complex binding to DNA has been determined by fluorescence titration in 0.05 M Tris-HCl, 0.5 M NaCl buffer (pHb = 7.0). The results indicate that the interaction of the complex with DNA is very evident. [ABSTRACT FROM AUTHOR]

Controlling selectivity between homochiral and heterochiral reaction pathways on surfaces remains a great challenge. Here, competing reactions of a prochiral alkyne on Ag(111): two-dimensional (2D) homochiral Glaser coupling and heterochiral cross-coupling with a Bergman cyclization step have been examined. We demonstrate control strategies in steering the reactions between the homochiral and heterochiral pathways by tuning the precursor substituents and the kinetic parameters, as confirmed by high-resolution scanning probe microscopy (SPM). Control experiments and density functional theory (DFT) calculations reveal that the template effect of organometallic chains obtained under specific kinetic conditions enhances Glaser coupling between homochiral molecules. In contrast, for the reaction of free monomers, the kinetically favorable reaction pathway is the cross-coupling between two heterochiral molecules (one of them involving cyclization). This work demonstrates the application of kinetic control to steer chiral organic coupling pathways at surfaces. Controlling selectivity between homochiral and heterochiral reaction pathways on surfaces is intriguing but challenging. Here, the authors demonstrate strategies in steering the reactions of prochiral terminal alkynes between the homochiral and heterochiral pathways by tuning the precursor substituents and the kinetic parameters. [ABSTRACT FROM AUTHOR]