Yucheng Ma

One bioprobe: a fluorescent and AIE-active macromolecule; two targets: nucleolus and mitochondria with long term tracking

Specific organelle imaging and long-term cellular tracking are of paramount importance in monitoring biological processes, pathological pathways, and therapeutic effects, etc. Herein, we report a novel macromolecule fluorescent probe (TPPA-DBO), which is synthesized from tris(4-(pyridin-4-yl)phenyl)amine (TPPA) and 1,8-dibromononane (DBO) with a gram scale by a simple method. TPPA-DBO demonstrates a highly specific nucleolus-targeting ability, which is very challenging in the bioimaging research field. We have shown that the green nucleolus-specificity probe TPPA-DBO has advantages over the commercially available nucleolus-staining probes such as DAPI, Hoechst dyes and SYTOs in terms of its AIE-performance, large Stokes shift (175 nm), excellent photostability, and promising usefulness in live cell imaging experiments. Surprisingly, after internalizing TPPA-DBO into the nucleus region for a period of time, some TPPA-DBO are reversely diffused from nucleolus into the cytoplasm, thus resulting in the staining of mitochondria with a redder emission color. This research result may provide a new concept of cellular tracker design and provide insight into biological questions, understanding disease mechanismss, and designing new therapeutic strategies.

Fluorophore-functionalized graphene oxide with application in cell imaging

In this work, we fabricated a novel triphenylamine-derivative (DNDT)-modified nanographene oxide by following a simple gram-scale method. The product showed interesting optical properties and good potential for use in bioimaging applications. This fluorescent carbon material could be readily internalized by HepG2 cells and was clearly visualized to accumulate mainly in the nucleus.

Positively Charged Hyperbranched Polymers with Tunable Fluorescence and Cell Imaging Application.

Fluorescence-tunable materials are becoming increasingly attractive because of their potential applications in optics, electronics, and biomedical technology. Herein, a multicolor molecular pixel system is realized using a simple copolymerization method. Bleeding of two complementary colors from blue and yellow fluorescence segments reproduced serious multicolor fluorescence materials. Interestingly, the emission colors of the polymers can be fine-tuned in the solid state, solution phase, and in hydrogel state. More importantly, the positive fluorescent polymers exhibited cell-membrane permeable ability and were found to accumulate on the cell nucleus, exhibiting remarkable selectivity to give bright fluorescence. The DNA/RNA selectivity experiments in vitro and in vivo verified that [tris(4-(pyridin-4-yl)phenyl)amine]-[1,8-dibromooctane] has prominent selectivity to DNA over RNA inside cells.

BSA-coated fluorescent organic–inorganic hybrid silica nanoparticles: preparation and drug delivery

It is desirable to engineer bio-compatible construction materials and cargo release vehicles with efficient cargo loading capability and controlled drug delivery ability. Herein, an inorganic–organic hybrid composite DNDT&SiO2–NH2@BSA was established using two steps. Technologically, the fluorescent DNDT was grafted on the particles surface via solid phase synthesis, which was able to report the occurrence of interactions between the silica cores and proteins of bovine serum albumin (BSA) by real-time optical change analysis. It should be noted that the construction method derived from this study can be transposed easily to other surface modification procedures. Interestingly, DNDT&SiO2–NH2@BSA could be dispersed into an aqueous phase very well, leading to a homogeneous distribution of the drug over the matrix with a more efficient manner. Furthermore, due to the temperature-dependent α-helix content changes, the encapsulators of BSA can capture the drugs at low temperature and release them with elevating temperature. In particular, a desirable controlled release is realized at 37 °C.

Multiple cation-doped linear polymers toward ATP sensing and a cell imaging application

A set of multiple cation-doped linear polymers (abbreviated as OPY-1,2-BE, OPY-1,4-BB, OPY-1,8-BO, OPY-1,4-OBB) synthesized from a dipyridine derivative (OPY) and dibrominated compounds were employed as fluorescent probes for adenosine triphosphate (ATP) sensing. Among them, OPY-1,8-BO is particularly able to recognize ATP over its related compounds adenosine diphosphate (ADP), adenosine monophosphate (AMP), and other phosphate anions, with very desirable switch off–on performances. The interesting phenomenon of aggregate-induced emission (AIE) is proposed as the main reason for the ATP sensing, which is due to the ATP being more negative than the polymers and therefore there is more opportunity for connections with the multiple cation doped polymers through electrostatic attractions. Cell imaging measurements were carried out and demonstrated that even though these probes bear the same OPY core and only slightly different linkers, they are able to image different cell environments. The controlled cell imaging verified that the OPY-1,8-BO probe has ATP-specific recognition in living cells.

A direct crossed polymerization of triphenylamines and cyclohexanones via CC bond formation: the method and its bioimaging application

The effective polymerization process is very desirable in the field of macromolecule science. In this study, we present a facile synthetic method via aldol addition and condensation (AAC) that leads to the formation of fluorescent linear and branched polymers by cross coupling triphenylamines (TPA) and cyclohexanones (CYC) via CC bond formation. The methodology has the advantage of easy operations, mild reaction conditions, and high yield. Via the analysis of NMR, FT-IR, GPC, PL, UV, SEM, and theoretical calculation, the structure, physical properties, and optical behaviors of both polymers were well-characterized. The understanding of cell transplantation, migration, division, fusion, and lysis is a very challenging task. In this study, the linear polymer (LP) exhibits excellent biocompatibility and low cytotoxicity, which can be readily internalized by living cells in a noninvasive manner. The images of MPC5 cells indicate that LP can be a promising emissive fluorescence probe for bioimaging application.