Chunzhi Cui

Effectively enhancing the room-temperature phosphorescence (RTP) emission of pure organic phosphors is the goal that scholars continue to pursue. In this study, as a novel strategy, diacetylene monomers were introduced into a pure organic molecule, 2-(9H-carbazol-9-yl)ethanol (CZEO). Upon UV irradiation, the formed polydiacetylene (PDA) backbones caused a significant enhancement in the RTP emission. RTP emission continuously enhanced with the time UV irradiation. In addition, the synergistic enhancement with the help of halogen bonds was realized by introducing Br atoms into the CZEO unit.

In this research, by simultaneously regulating the two major factors affecting the plasmonic enhanced fluorescence (PEF), spectral overlap and the distance between the fluororophores and the noble metal nanoparticles, a significantly enhanced fluorescent signal is achieved. Core‐shell nanostructures composed of aspect ratio (AR) adjustable gold nanorods (GNRs) and various thickness of SiO₂ are prepared and the decorated fluorophores are realized optimized PEF. A typical stimuli‐responsive conjugated polymer, polydiacetylene (PDA), and a near‐infrared (NIR) dye Cy5.5 are selected as fluorophores and their fluorescent signal are enhanced 7.26 and 4.41 times, respectively. Based on the optimized optical properties, a multifunctional antibody modified Mab‐Cy5.5‐GNRs@SiO₂ is successfully demonstrated the targeting, imaging, and photothermal therapy (PTT) effects on SKOV‐3 ovarian cancer cells.

In this study, we prepared novel hybrid assemblies composed of a small Schiff base molecule, (E)-1-(4-(dimethylamino)-phenyl)iminomethyl-2-hydroxyl-naphthalene (DPIN), and single strand DNAs (ssDNAs). Owing to clustering-triggered emission (CTE), aggregated hybrid assemblies emit a strong fluorescence signal. However, after incubation with specific target DNA (tDNA) sequences, the formed double helical DNAs dispersed the hybrid assemblies and contributed to the decrease in the fluorescence signal. By contrast, the cases of 1-mer and random mismatched tDNA sequences did not show any such diminished fluorescence signal.

The significance of DNA is no longer limited to its role as a biological information carrier; as a natural polymer, it also become in the field of materials. Single-stranded DNA (ssDNA) molecules with specific sequences can form a G-quadruplex or hairpin-shaped conformation with specific heavy metal ions through coordination bonds. In this study, ssDNA molecules of the four sequences were prepared into hybrid assemblies with one of the famous display materials, the tris-(8-hydroxyquinoline)aluminum (Alq₃) semiconductor. Based on these hybrid assemblies, heavy metal ions, namely Pb²⁺, Hg²⁺, Cd²⁺ and As³⁺, were detected individually at the ppb level. Apart from this, in practical application, many samples containing heavy metal ions are digested with acid. By introducing MES buffer solution, the influence of acidity on the fluorescent signal of Alq₃ was excluded. This strategy showed promising results in the practical application of detecting heavy metal ions in shrub branches and leaves.

We experimentally demonstrate the simultaneous enhancement of Raman and photoluminescence (PL) of core-shell hybrid nanoparticles consisting of Ag (core) and polydiacetylene (PDA, shell) through the assistance of localized surface plasmon (LSP) effect for the effective biosensor. Core-shell nanoparticles (NPs) are fabricated in deionized water through a sequential process of reprecipitation and self-assembly. The Raman signal of PDA on core-shell NPs is enhanced more than 100 times. Also, highly enhanced photoluminescence is observed on Ag/PDA hybrid NPs after coupling of the complementary t-DNA with p-DNA which are immobilized on PDA shell. This indicates that the core Ag affects the Raman and PL of PDA through the LSP resonance, which can be caused by the energy and/or charge transfer caused by the LSP coupling and the strong electromagnetic field near Ag NP surface. Only electrons present on the surface interact with the PDA shell, not involving the electrically neutral part of the electrons inside the Ag NP. Furthermore, this work shows that as prepared Ag/PDA NPs functionalized by probe DNA can sense the target DNA with an attomolar concentration (100 attomole).

Two organic molecules, 10,12-pentacodiynoic acid (PCDA) and para-xylenediamine (pXDA), were complex in THF solution upon acid-base interactions and assembled into thin films with a highly ordered structure after evaporation of the solvent. The binding specificities of α-, β-, and γ-cyclodextrins (CDs) with the photopolymerized polydiacetylenic films were studied. According to the optical, morphological, and structural analyses, it was found that the films were preferentially interacted with α-CDs, as well as host-guest interaction. In addition, the polydiacetylenic films were applicable for recognizing toxic materials as aldehyde derivatives in both liquid and gas states. These fundamental results may provide more useful platforms of polydiacetylene-based materials as optoelectronic devices or chemical/biological sensors.