Electroporation-Assisted Surface-Enhanced Raman Detection for Long-Term, Label-Free, and Noninvasive Molecular Profiling of Live Single Cells

Molecule characterization of live single cells is greatly important in disease diagnoses and personalized treatments. Conventional molecule detection methods, such as mass spectrography, gene sequencing, or immunofluorescence, are usually destructive or labeled and unable to monitor the dynamic change of live cellular molecules. Herein, we propose an electroporation-assisted surface-enhanced Raman scattering (EP-SERS) method using a microchip to implement label-free, noninvasive, and continuous detections of the molecules of live single cells. The microchip containing microelectrodes with nanostructured EP-SERS probes has a multifunction of cell positioning, electroporation, and SERS detection. The EP-SERS method capably detects both the intracellular and extracellular molecules of live single cells without losing cell viability so as to enable long-term monitoring of the molecular pathological process in situ. We detect the molecules of single cells for two breast cancer cell lines with different malignancies (MCF-7 and MDA-MB-231), one liver cancer cell line (Huh-7), and one normal cell line (293T) using the EP-SERS method and classify these cell types to achieve high accuracies of 91.4–98.3% using their SERS spectra. Furthermore, 24 h continuous monitoring of the heterogeneous molecular responses of different cancer cell lines under doxorubicin treatment is successfully implemented using the EP-SERS method. This work provides a long-term, label-free, and biocompatible approach to simultaneously detect intracellular and extracellular molecules of live single cells on a chip, which would facilitate research and applications of cancer diagnoses and personalized treatments

Computer-Vision-Based Dielectrophoresis Mobility Tracking for Characterization of Single-Cell Biophysical Properties

Fast and precise measurements of live single-cell biophysical properties is significant in disease diagnosis, cytopathologic analysis, etc. Existing methods still suffer from unsatisfied measurement accuracy and low efficiency. We propose a computer vision method to track cell dielectrophoretic movements on a microchip, enabling efficient and accurate measurement of biophysical parameters of live single cells, including cell radius, cytoplasm conductivity, and cell-specific membrane capacitance, and in situ extraction of cell texture features. We propose a prediction-iteration method to optimize the cell parameter measurement, achieving high accuracy (less than 0.79% error) and high efficiency (less than 30 s). We further propose a hierarchical classifier based on a support vector machine and implement cell classification using acquired cell physical parameters and texture features, achieving high classification accuracies for identifying cell lines from different tissues, tumor and normal cells, different tumor cells, different leukemia cells, and tumor cells with different malignancies. The method is label-free and biocompatible, allowing further live cell studies on a chip, e.g., cell therapy, cell differentiation, etc

Stable Ionic Rh(I,II,III) Complexes Ligated by an Imidazolium-Substituted Phosphine with π‑Acceptor Character: Synthesis, Characterization, and Application to Hydroformylation

The stable ionic Rh­(I,II,III) complexes [Rh^I(acac)­(CO)­(<b>L</b>)]­PF₆ (<b>2</b>), [Rh^II₂(OAc)₄(<b>L</b>)₂]­2PF₆ (<b>3</b>), and [Rh^IIICl₄(<b>L</b>)₂]­PF₆ (<b>4</b>) were synthesized through the complexation of Rh^I(acac)­(CO)₂, Rh^II₂(OAc)₄(H₂O)₂, and Rh^IIICl₃·3H₂O with the phosphine-functionalized ionic liquid (FIL) <b>1</b> ([<b>L</b>]­PF₆, <b>L</b> = 1-butyl-2-diphenylphosphino-3-methylimidazolium), respectively. The cation of <b>L</b> in <b>1</b> is an imidazolium-substituted phosphine with a positive charge vicinal to the P­(III) atom, which acts as an electron-deficient donor with π-acceptor character to afford the stable complexes <b>2</b>–<b>4</b> due to the presence of retrodonating π-binding between Rh–P linkage. Due to the weakened reducing ability of <b>L</b>, the redox reaction between <b>L</b> and RhCl₃·3H₂O during the complexation is avoided, leading to the formation of <b>4</b>, in which the Rh center is in the +3 valence state. Single-crystal X-ray analyses show that <b>2</b>–<b>4</b> are all composed of a Rh-centered cation and a PF₆^– counteranion. The cation of <b>2</b> possesses structural similarity to Rh^I(acac)­(CO)­(PPh₃), the cation of <b>3</b> with a <i>D</i>_4<i>h</i> geometry possesses a structural similarity to Rh^II₂(OAc)₄(PPh₃)₂, and the cation of <b>4</b> exhibits an ideal Rh^III-centered octahedral geometry, in which the Rh­(III) (d⁶) ion is six-coordinated by four chlorine atoms in the equatorial plane and two <b>L</b> ligands in the axial positions. TG/DTG analyses indicated that the thermal stabilities of <b>2</b>–<b>4</b> in air flow were improved dramatically in comparison to the corresponding analogues Rh^I(acac)­(CO)­(PPh₃), Rh^II₂(OAc)₄(PPh₃)₂, and Rh^ICl­(PPh₃)₃. <b>2</b>–<b>4</b> were found to be good to excellent catalysts for homogeneous hydroformylation of 1-octene free of any auxiliary ligand; <b>3</b> was the best candidate. The “on water” effect in rate acceleration was evidently observed over <b>2</b> and <b>4</b> due to their insensitivity to moisture and oxygen

Stable Ionic Rh(I,II,III) Complexes Ligated by an Imidazolium-Substituted Phosphine with π‑Acceptor Character: Synthesis, Characterization, and Application to Hydroformylation

The stable ionic Rh­(I,II,III) complexes [Rh^I(acac)­(CO)­(<b>L</b>)]­PF₆ (<b>2</b>), [Rh^II₂(OAc)₄(<b>L</b>)₂]­2PF₆ (<b>3</b>), and [Rh^IIICl₄(<b>L</b>)₂]­PF₆ (<b>4</b>) were synthesized through the complexation of Rh^I(acac)­(CO)₂, Rh^II₂(OAc)₄(H₂O)₂, and Rh^IIICl₃·3H₂O with the phosphine-functionalized ionic liquid (FIL) <b>1</b> ([<b>L</b>]­PF₆, <b>L</b> = 1-butyl-2-diphenylphosphino-3-methylimidazolium), respectively. The cation of <b>L</b> in <b>1</b> is an imidazolium-substituted phosphine with a positive charge vicinal to the P­(III) atom, which acts as an electron-deficient donor with π-acceptor character to afford the stable complexes <b>2</b>–<b>4</b> due to the presence of retrodonating π-binding between Rh–P linkage. Due to the weakened reducing ability of <b>L</b>, the redox reaction between <b>L</b> and RhCl₃·3H₂O during the complexation is avoided, leading to the formation of <b>4</b>, in which the Rh center is in the +3 valence state. Single-crystal X-ray analyses show that <b>2</b>–<b>4</b> are all composed of a Rh-centered cation and a PF₆^– counteranion. The cation of <b>2</b> possesses structural similarity to Rh^I(acac)­(CO)­(PPh₃), the cation of <b>3</b> with a <i>D</i>_4<i>h</i> geometry possesses a structural similarity to Rh^II₂(OAc)₄(PPh₃)₂, and the cation of <b>4</b> exhibits an ideal Rh^III-centered octahedral geometry, in which the Rh­(III) (d⁶) ion is six-coordinated by four chlorine atoms in the equatorial plane and two <b>L</b> ligands in the axial positions. TG/DTG analyses indicated that the thermal stabilities of <b>2</b>–<b>4</b> in air flow were improved dramatically in comparison to the corresponding analogues Rh^I(acac)­(CO)­(PPh₃), Rh^II₂(OAc)₄(PPh₃)₂, and Rh^ICl­(PPh₃)₃. <b>2</b>–<b>4</b> were found to be good to excellent catalysts for homogeneous hydroformylation of 1-octene free of any auxiliary ligand; <b>3</b> was the best candidate. The “on water” effect in rate acceleration was evidently observed over <b>2</b> and <b>4</b> due to their insensitivity to moisture and oxygen

Molecular Structure and Physicochemical Properties of Starches from Rice with Different Amylose Contents Resulting from Modification of OsGBSSI Activity

OsGBSSI, encoded by the <i>Waxy</i> (<i>Wx</i>) gene, is the key enzyme in the synthesis of amylose chains. Transgenic rice lines with various GBSSI activities were previously developed via site-directed mutagenesis of the <i>Wx</i> gene in the glutinous cultivar Guanglingxiangnuo (GLXN). In this study, grain morphology, molecular structure, and physicochemical properties were investigated in four transgenic lines with modified OsGBSSI activity and differences in amylose content. A milky opaque appearance was observed in low- and non-amylose rice grains due to air spaces in the starch granules. Gel permeation chromatography (GPC) and high-performance anion-exchange chromatography (HPAEC) analyses showed that although OsGBSSI can synthesize intermediate and extra-long amylopectin chains, it is mainly responsible for the longer amylose chains. Amylose content was positively correlated with trough viscosity, final viscosity, setback viscosity, pasting time, pasting temperature, and gelatinization temperature and negatively with gel consistency, breakdown viscosity, gelatinization enthalpy, and crystallinity. Overall, the findings suggest that OsGBSSI may be also involved in amylopectin biosynthesis, in turn affecting grain appearance, thermal and pasting properties, and the crystalline structure of starches in the rice endosperm