High-efficiency fluorescent coordination polymer nanoparticles co-doped with Ce3+/Tb3+ ions for curcumin detection.

Curcumin (Cur) possesses diverse biological and pharmacologic effects. It is widely used as a food additive and therapeutic medicine. A study to determine a sensitive detection method for Cur is necessary and meaningful. In this work, double rare earth ions co-doped fluorescent coordination polymer nanoparticles (CPNPs) were developed for the Cur detection. The CPNPs were synthesized by using adenosine monophosphate (AMP) as bridge ligands via coordination self-assembly with Ce3+ and Tb3+. The AMP-Ce/Tb CPNPs exhibited the characteristic green fluorescence of Tb3+ and had high luminescence efficiency. Under the optimal conditions, the fluorescence intensity of AMP-Ce/Tb CPNPs could be significantly quenched by Cur. The fluorescence quenching extent at λex/λem of 300 nm/544 nm showed a good linear relationship with the Cur concentration in the range of 10 to 1000 nM. The detection limit was as low as 8.0 nM (S/N = 3). This method was successfully applied to the determination of Cur in real samples with satisfactory results. The luminescence mechanism of AMP-Ce/Tb CPNPs and the fluorescence quenching mechanism of the CPNPs by Cur were both examined.

Covalent-reaction-induced interfacial assembly to transform doxorubicin into nanophotomedicine with highly enhanced anticancer efficiency.

Herein, we show that a molecular assembly offers tremendous opportunities of affording existing building units with new physicochemical properties, holding promise in wide applications. Herein, we develop a facile covalent assembly using a natural occurring linker, genipin, to efficiently transform a traditional chemo drug, doxorubicin, into a nanophotomedicine. A possible mechanism is proposed, in which doxorubicin reacts with genipin through covalent bonding to produce poorly soluble units, which further form nuclei and mediate the interfacial assembly to generate uniform nanoparticles. Such assembled nanophotomedicine shows remarkably enhanced singlet oxygen generation ability (about 1000 folds), leading to a much higher photodynamic activity. Moreover, this self-carried nanodrug exhibits adjustable size, excellent colloidal stability, high capacity and preferable endocytosis. These favorable features lead to greatly improved anticancer efficiency under light at the same dosage, compared to that of pure doxorubin. We believe this study brings a new dimension to develop advanced drug delivery systems by molecular assembly.

Gelatin-Assisted Synthesis of Vaterite Nanoparticles with Higher Surface Area and Porosity as Anticancer Drug Containers In Vitro.

The fabrication of porous vaterite nanoparticles with improved stability in aqueous solution and higher surface area is still a challenge. Here, inspired by the formation of mesoporous silica nanoparticles, we have taken gelatin as a "surfactant" to assist in the formation of vaterite nanoparticles and help create pores on their surface due to the distinct solubility and molecular morphology of gelatin in different solutions. The formation mechanism of vaterite nanoparticles and pores was investigated in detail, indicating that the existence of gelatin has a crucial effect on the formation of vaterite nanoparticles and their stability. Meanwhile, the elution of gelatin from vaterite nanoparticles via washing with hot water accounts for their higher surface area. Their application as an anticancer drug (doxorubicin) carrier after folic acid treatment was also investigated. These nanoparticles have advantages for drug release due to their pH-sensitive structure and also have enhanced cytotoxicity toward cancer cells due to the folic acid modification.

Synthesis of Peptide-Based Hybrid Nanobelts with Enhanced Color Emission by Heat Treatment or Water Induction.

We demonstrate that an inorganic lanthanide ion (Tb(3+)) or organic dye molecules were encapsulated in situ into diphenylalanine (FF) organogels by a general, simple, and efficient co-assembly process, which generated peptide-based hybrid nanobelts with a range of colored emissions. In the presence of a photosensitizer (salicylic acid), the organogel can serve as an excellent molecular-donor scaffold to investigate FRET to Tb(3+). More importantly, heat treatment or water induction instigated a morphology transition from nanofibers to nanobelts, after which the participation of guest molecules in the FF assembly was promoted and the stability and photoluminescence emission of the composite organogels were enhanced.

CuInS2 quantum dots as a near-infrared fluorescent probe for detecting thrombin in human serum.

This paper describes a novel, simple method for the highly sensitive and selective detection of thrombin using fibrinogen (Fib) and CuInS(2) quantum dots (QDs) as biosensing probes. Water-soluble near-infrared CuInS(2) QDs capped by mercaptopropionic acid (MPA) were directly synthesized by a hydrothermal method. Addition of fibrinogen to the CuInS(2) QDs solution led to the formation of a Fib-CuInS(2) QDs complex through electrostatic interactions and hydrogen bonding, and resulting in the enhancement of photoluminescence (PL) intensity and a red shift of the PL peak. Once thrombin was introduced into the Fib-CuInS(2) QDs system, it catalyzed the polymerization of the free and conjugated fibrinogen species to form insoluble fibrillar fibrin-CuInS(2) QDs agglutinates. After centrifugation, the PL intensity of the supernatants decreased upon increasing the concentration of thrombin. This Fib-CuInS(2) QDs probe provided a highly specific selectivity and a linear detection of thrombin in the range of 6.7 × 10(-11) to 3.9 × 10(-7) mol L(-1) with a detection limit (LOD) of about 8.7 × 10(-12) mol L(-1), and realized the thrombin detection in human serum samples directly. Compared with those obtained by using other nanomaterials and aptamer-based detection methods, this approach provided a lower LOD for thrombin detection. The proposed approach provides a simple and fast-responding procedure, which might hold a promising potential for application in the diagnosis of diseases associated with coagulation abnormalities and cancers.