Chenyao Nie

Multicellular Assembly and Light-Regulation of Cell–Cell Communication by Conjugated Polymer Materials

Using cell-surface modification and biotin-streptavidin interactions, immune cells and target tumor cells are made to form multicellular assemblies. A polythiophene derivative can undergo cellular uptake, allowing the sensitization of oxygen under light irradiation. The subsequent generation of reactive oxygen species (ROS) regulates cell-cell communication in time and space.

Cationic oligo(p-phenylene vinylene) materials for combating drug resistance of cancer cells by light manipulation.

An unconventional strategy that can be temporally and remotely activated with light to combat the drug resistance of cancer cells is developed. A cell-membrane-anchored photosensitizer (OPV) is used to enhance anticancer drug uptake and restore toxicity in resistant cancer cells. This method recovers the activity of the already established anticancer drugs, and provides a new strategy for the development of light manipulation to combat anticancer resistance.

Fluorescence Ratiometric Assay Strategy for Chemical Transmitter of Living Cells Using H2O2-Sensitive Conjugated Polymers

A new water-soluble conjugated poly(fluorene-co-phenylene) derivative (PFP-FB) modified with boronate-protected fluorescein (peroxyfluor-1) via PEG linker has been designed and synthesized. In the presence of H2O2, the peroxyfluor-1 group can transform into green fluorescent fluorescein by deprotecting the boronate protecting groups. In this case, upon selective excitation of PFP-FB backbone at 380 nm, efficient fluorescence resonance energy transfer (FRET) from PFP-FB backbone to fluorescein occurs, and accordingly, the fluorescence color of PFP-FB changes from blue to green. Furthermore, the emission color of PFP-FB and the FRET ratio change in a concentration-dependent manner. By taking advantage of PFP-FB, ratiometric detection of choline and acetylcholine (ACh) through cascade enzymatic reactions and further dynamic monitoring of the choline consumption process of cancer cells have been successfully realized. Thus, this new polymer probe promotes the development of enzymatic biosensors and provides a simpler and more effective way for detecting the chemical transmitter of living cells.

Conjugated Polymer Nanoparticles for Cell Membrane Imaging

The outstanding optical properties and biocompatibility of fluorescent conjugated polymer nanoparticles (CPNs) make them favorable for bioimaging application. However, few CPNs could achieve stable cell membrane labeling due to cell endocytosis. In this work, conjugated polymer nanoparticles (PFPNP-PLE) encapsulated with PFP and PLGA-PEG-N3 in the matrix and functionalized with the small-molecule drug plerixafor (PLE) on the surface were prepared by a mini-emulsion method. PFPNP-PLE exhibits excellent photophysical properties, low cytotoxicity, and specific cytomembrane location, which makes it a potential cell membrane labeling reagent with blue fluorescence emission, an important component for multilabel/multicolor bioimaging.

Multifunctional Assembly of Micrometer‐Sized Colloids for Cell Sorting

Compared to the extensively studied nanometer-sized colloids, less attention has been paid to the assembly of micrometer-sized colloids with multifunctional characteristics. To address this need, a bottom-up approach is developed for constructing self-assemblies of micrometer-sized magnetic colloids possessing multifunctionality, including magnetic, optical, and biological activities. Biotinylated oligo (p-phenylene vinylene) (OPV) derivatives are designed to mediate the self-assembly of streptavidin-modified magnetic beads. The optical element OPV derivatives provide a fluorescence imaging ability for tracing the assembly process. Target cells can be recognized and assembled by the colloidal assembly with bioactive element antibodies. The colloidal assembly reveals better cell isolation performance by its amplified magnetic response in comparison to monodisperse colloids. The self-assembly of micrometer-sized magnetic colloids through a combination of different functional ingredients to realize multifunction is conceptually simple and easy to achieve.

Synthesis of a new conjugated polymer for DNA alkylation and gene regulation.

A new polyfluorene derivative containing pendent alkylating chlorambucil (PFP-Cbl) was synthesized and characterized. Under direct incubation with DNA in vitro, PFP-Cbl could undergo an efficient DNA alkylating reaction and induce DNA cross-linking. In vitro transcription and translation experiment exhibited that the PFP-Cbl significantly down-regulated the gene expression of luciferase reporter plasmid. The down-regulation of gene expression was also verified through the transfection experiment of p-EGFP plasmid, which showed decreased green fluorescent protein (GFP) in cells. Meanwhile, the self-luminous property of PFP-Cbl could make it able to trace the internalized PFP-Cbl and plasmid complexes resulted from cross-linking in cells by fluorescent microscopy. Combining the features of alkylating function, multivalent binding sites, and fluorescent characteristics, PFP-Cbl provides a new insight in the area of gene regulation and extends the new applications of conjugated polymers (CPs).

Preparation of Reactive Oligo(p‐Phenylene Vinylene) Materials for Spatial Profiling of the Chemical Reactivity of Intracellular Compartments

An oligo(p-phenylene vinylene) derivative (OPV-pfp) functionalized with pentafluorophenol active ester is designed and synthesized. The high reactivity of OPV-pfp with biological small molecules or macromolecules containing amino groups under physiological conditions leads to spectral changes of OPV-pfp; thus, spatial reactivity discrimination for different subcellular structures inside cells is realized by triggering and imaging the fluorescence signal change of the OPV-pfp.

ROS self-scavenging polythiophene materials for cell imaging

A conjugated polymer (PTDHP) was synthesized by modifying the side chain of cationic polythiophene (PT) with a dihydropyridine (DHP) group via a click reaction. PTDHP has a unique ROS self-scavenging ability through the oxidation of the DHP into a pyridine structure upon light irradiation. Thus, PTDHP achieves cell imaging with good photo-stability and low photo-cytotoxicity.