Higher Fluorescence Intensity Research Articles

Humic Acids Affect the Detection of Metal Ions by Cyanobacteria Carbon Quantum Dots Differently.

A “top-down” synthesis of carbon quantum dots (CQDs), novel fluorescent C materials from waste biomass, is both cost-effective and environmentally friendly. N-rich cyanobacteria are promising precursors to produce CQDs with high fluorescence (FL) intensity for the detection of metal ions. Herein, we synthesized cyanobacteria-based CQDs using a hydrothermal process and evidenced their high FL intensity and stability. The cyanobacteria-based CQDs showed powerful sensitivity for the specific detection of Fe3+ and Cr6+, which could be ascribed to (i) static FL quenching as a result of the interaction between –OH, –NH2, and –COOH groups with the metal ions, (ii) internal filtering effects between the CQDs and Fe3+ or Cr6+, and (iii) fluorescence resonance energy transfer between CQDs and Cr6+. Humic acids (HAs) coexisting led to an underestimation of Fe3+ but an overestimation of Cr6+ by the CQDs due to the different FL quenching mechanisms of the CQDs. HAs sorbed Fe3+ and wrapped the CQDs to form a barrier between them, inhibiting FL quenching of CQDs by Fe3+. As for Cr6+, HAs reduced Cr6+ and also led to FL quenching; the sorbed HAs on the CQDs acted as a carrier of electrons between Cr6+ and the CQDs, enhancing FL quenching of the CQDs. This study is the first work to evidence the interference of HAs in the detection of metal ions by CQDs derived from cyanobacteria, which would enlighten the application of CQDs in a natural aqueous environment.

NIR-Active Porphyrin-Decorated Lipid Microbubbles for Enhanced Therapeutic Activity Enabled by Photodynamic Effect and Ultrasound in 3D Tumor Models of Breast Cancer Cell Line and Zebrafish Larvae.

Porphyrin is known to enable the photodynamic effect during cancer drug delivery and molecular imaging. However, its hydrophobicity and tendency to aggregate in an aqueous medium create a significant hurdle for its use as an anticancer drug. Loading porphyrin onto biocompatible delivery vehicles can enhance its efficacy. This can be achieved by using gas-filled microbubbles that can be administered intravenously. This study aimed at developing near-infrared (NIR)-active porphyrin-loaded lipid microbubbles with anticancer activity enhanced by sonodynamic and photodynamic effects. The porphyrin-loaded microbubbles were studied for their cell toxicity, cellular uptake of porphyrin, and effect on cellular three-dimensional (3D) invasion of breast cancer cells (MDA-MB-231) in cellulo. Toxicity studies in zebrafish larvae (Danio rerio) in the presence and absence of photodynamic and sonodynamic therapy were also conducted. The results suggest that with a higher concentration of porphyrin loaded on microbubbles, the porphyrin-loaded microbubbles display a higher therapeutic effect facilitated by photodynamic and sonodynamic therapy, which results in enhanced cellular uptake and cellular toxicity. A lower concentration of loaded porphyrin microbubbles exhibits high cellular viability and good fluorescence intensity in the NIR region, which can be exploited for bioimaging applications.

Facile preparation of highly fluorescent nitrogen-doped graphene quantum dots for sensitive Fe3+ detection

Nitrogen-doped graphene quantum dots (N-GQDs) were synthesized by the hydrothermal method. The results of the transmission electron microscope and atomic force microscopy indicated that the average diameter and height of the homogeneously distributed N-GQDs were approximately 5 nm and less than 10 nm, respectively. The results of the X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy confirmed the successful incorporation of the N element into GQDs. The aqueous solution of N-GQDs dispersed in water remained stable and homogeneous at room temperature for 3 months. N-GQDs had a higher fluorescence intensity than GQDs and presented low toxicity and the survival rate of cells (3T3-Swiss albino) was more than 85% in the cytotoxicity test. To better understand the luminescence mechanism, the band gaps of GQDs and N-GQDs were calculated using the density functional theory (DFT). The effect of the pH value on the fluorescence intensity of N-GQDs before and after the addition of Fe3+ ions was investigated. N-GQDs were applied to selectively detect Fe3+ ions, and the results exhibited a wide linear correlation between the fluorescence intensity and the Fe3+ concentration of 0–100 uM with a detection limit of 0.74 uM. This study provided a simple and efficient synthesis method and proved the ultra-high Fe3+ detection selectivity and sensitivity of N-GQDs, offering the experimental and theoretical basis for N-GQDs’ applications in biosensing, bioimaging, environmental monitoring, etc.

A Small-Molecule Based Organic Nanoparticle for Photothermal Therapy and Near-Infrared-IIb Imaging.

Near-infrared window IIb (NIR-IIb, 1500-1700 nm) fluorescence imaging demonstrates attractive properties including low scattering, low absorption, and deep tissue penetration, and photothermal therapy (PTT) is also a promising modality for cancer treatment. However, until now, there is no report on theranostic systems based on small organic molecules combining fluorescence imaging in the NIR-IIb and PTT, highlighting the challenge and strong need for development of such agents. Herein, we report a novel small molecule NIR-IIb dye IT-TQF with a D-A-D structure, which exhibited high fluorescence intensity in the NIR-IIb window. To further translate IT-TQF into an effective theranostic agent, IT-TQF was encapsulated into DSPE-PEG2000 to construct IT-TQF NPs. The physical and photochemical properties of the nanoprobe were investigated in vitro, and the in vivo NIR-IIb imaging and PTT performance were evaluated in normal, subcutaneous, orthotopic, and metastatic tumor mice models. IT-TQF NP-based NIR-IIb imaging demonstrated high spatial resolution and high tissue penetration depth, and small normal blood vessels (55.3 μm) were successfully imaged in the NIR-IIb window. Subcutaneous, orthotopic, and metastatic tumors were all clearly delineated. A high tumor signal-to-background ratio (SBR) of 9.42 was achieved for orthotopic osteosarcoma models, and the erosions of bone tissue caused by tumor cells were precisely visualized. Moreover, NIR-II image-guided surgery was successfully performed to completely remove the orthotopic tumor. Importantly, IT-TQF NPs displayed high PTT efficacy (photothermal conversion efficiency: 47%) for effective treatment of tumor mice. In conclusion, IT-TQF NPs are a novel and promising phototheranostic agent in the NIR-IIb window, and the nanoprobe has high potential for a broad range of biomedical applications.

Fluorescent adenine analogues with ESPT characteristic utilized for real-time detecting DNA adduct

The 8-oxo-7,8-dihydro-2′-deoxyguanine (8-oxoG) is the representative damaged nucleoside that may increase the risk of developing diseases. Accordingly, the selective detection of 8-oxoG in DNA with minimal disturbance to the native structure is important to have an in-depth understanding of the formation mechanism and becomes an attractive tool for genomic research. To identify the DNA adduct in real-time efficiently, a series of quasi-intrinsic optical probes are performed based on the natural adenine, which has preference to form a stable base pair with 8-oxoG in the syn conformation. The calculations revealed that the A-analogues in solution could bring red-shifted absorption spectra and bright photoluminescence arisen from the additional π-conjugation by means of fluorophore modification and the ring expansion. Especially, A1 possesses large Stokes shifts and the highest fluorescence intensity in emission, which is proposed as the biosensor to monitor the optical changes in the presence and absence of the considered 8-oxoG. It is found that the fluorescence is insensitive to base pairing with thymine, while the excited state intermolecular proton transfer (ESPT) induced efficient fluorescence quenching is observed upon pairing with the 8-oxoG. To evaluate the direct usefulness of the bright adenine analogues in biological environment, we further examined the influences of linking deoxyribose on the absorption and emission, which are consistent with the experimental data.

Insights into the effects of dynamic high-pressure microfluidization on the structural and rheological properties of rapeseed protein isolate

The application of dynamic high-pressure microfluidization (DHPM) provides interesting modifications in food structures. However, the effects of DHPM on the structural and rheological properties of rapeseed protein isolate (RPI) were scarcely investigated. In this study, the average hydrodynamic size of RPI treated by DHPM significantly declined from 239.2 nm to 170 nm with the pressure and time rising to 60 MPa and 2 min. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis found that DHPM did not affect the molecular mass of the RPI. The changes in the intrinsic fluorescence and circular dichroism spectra showed that tertiary and secondary structures of RPI were altered, as proved by the higher fluorescence intensity and greater conversion of random coils and β-sheets into α-helices compared with the control (unprocessed RPI). The spatial unfolding of the RPI structure and the dissociation of chemical bonds influenced its rheological behavior. All RPI suspensions (15%, w/v) processed by DHPM had lower apparent viscosity, moduli, higher gelling temperature (up to 69.7 °C) than control, and the differences in rheological performance were closely dependent on the treatment pressure and time. In conclusion, through this study of the effects of DHPM on RPI, DHPM was shown to be a potential method for modifying proteins and reducing the consistency of high-protein fluid foods.

A Bioinspired Light Harvesting System in Aqueous Medium: Highly Efficient Energy Transfer through the Self Assembly of β-Sheet Nanostructures of Poly-d-Lysine

Nature has beautifully assembled its light harvesting pigments within protein scaffolds, which ensures a very high energy transfer. Designing a highly efficient artificial bioinspired light harvesting system (LHS) thus requires the nanoscale spatial orientation and electronic control of the associated chromophores. Although DNA has been used as a scaffold to organize chromophores, proteins or polypeptides, however, are very rarely explored. Here, we have developed a highly efficient, artificial, bioinspired LHS using polypeptide (poly-d-lysine, PDL) nanostructures making use of their β-sheet structure in an aqueous alkaline medium. The chromophores used herein are compatible for an energy transfer process and are nonfluorescent in an aqueous medium but exhibit high fluorescence intensity when bound to the nanostructure of PDL. The close proximity of the chromophores results in an energy transfer efficiency of ∼92% besides generating white light emission at a particular molar ratio between the chromophores.

Fluorescent/magnetic nano-aggregation via electrostatic force between modified quantum dot and iron oxide nanoparticles for bimodal imaging of U87MG tumor cells.

Imaging technology based on novel nanomaterials is burgeoning as a potential tool for exploring various physiological processes. We herein report a fluorescent and magnetic nanoprobe (QMNP-RGD) for bimodal imaging of in vitro tumor cells. The preparation of this multifunctional nanomaterial is divided into three steps. First, commercial quantum dots (QDs) with high fluorescence intensity are covalently modified with an RGD peptide, which can facilitate the tumor cell uptake by αvβ3 integrin-induced active recognition. Superparamagnetic iron oxide (SPIO) nanoparticles (NPs) are then capped using a cationic polysaccharide to improve stability. Integration is finally achieved by convenient electrostatic binding. We successfully demonstrated that QMNP-RGD can be efficiently delivered into U87MG cells and used for fluorescence/magnetic resonance (MR) bimodal imaging. Other multimodal probes may be able to be designed for imaging based on this strategy of electrostatic binding.

H2O brace molecules to slip stack: Transform ACQ to AIE for latent fingerprints recognition

Aggregation-induced emission (AIE) materials have received a lot of attention in recent years, however, it remains a great challenge to develop a facile method for the conversion of aggregation-caused quenching (ACQ) molecules to AIE. In this paper, the ACQ molecule, 3,5-diacetyl-1,4-dihydro-2,6-lutidine (DDL), is successfully transformed from face-to-face stacking to slip stacking under the induction of H2O, achieving the transformation of ACQ molecule to AIE. Experimental analysis and theoretical calculations show that H2O is inserted into DDL molecules through hydrogen bonds, and its spatial configuration makes an angle between the H2O and DDL planes, thus increasing the horizontal and vertical distances between adjacent DDL molecules, so that DDL is arranged in a slip stacking pattern. Meanwhile, hydrogen bonds fix the DDL molecules in a relatively rigid structure, leading to the generation of other weak interactions, which further restrict the molecular motion and reduce the non-radiative transitions, so that the DDL possesses the AIE property, and the quantum yield increases from 0.95 % to 25.60 %. Based on the high fluorescence intensity of DDL-H2O, it has been successfully applied to the first-, second- and tertiary-level structures of latent fingerprints (LFPs) identification, which provides more possibilities for the practical application of ACQ molecules.

Toxicological Impact and in Vivo Tracing of Rhodamine Functionalised ZIF-8 Nanoparticles.

Metal Organic Frameworks (MOFs) are extensively used for a wide range of applications due to their exceptionally high surface area. MOF particles are conventionally in micron size, but the nanosized MOFs show good transportation/mobility due to their small size, and when combined with the high surface area of MOFs, it makes MOF nanoparticles an ideal candidate to study for environmental remediation. Therefore, it is important to study the ecotoxicological impact of these MOFs. In this study, we developed rhodamine labelled nanoparticles of zinc imidazolate metal organic framework (ZIF-8 MOFs) as a means of in vivo tracing the MOF translocation in C. elegans. Rhodamine B isothiocyanate functionalized ZIF-8 MOFs nanoparticles (RBITC@ZIF-8 MOF nanoparticles; size 44 ± 7 nm) were fed to the worms naturally within a concentration range of 0.16–16.4 μg mg−1. Fluorescence was detected in the pharyngeal and gut lumen regions of the worms after 4 h of treatment, for exposure concentrations >0.163 μg mg−1. A higher intensity of fluorescence was observed at the end of 24 h for all exposure concentrations. Worms treated with RBITC@ZIF-8 MOF concentrations of ≥1.63 μg mg−1 for 24 h showed a bright stable fluorescence signal at the tail region. The uptake of RBITC@ZIF-8 MOF for an exposure concentration of 0.163, 1.63, and 8.2 μg mg−1 was found to be 52.1, 11.4 and 28.6%, respectively. Through this study, we showed that RBITC@ZIF-8 MOFs can be exposed to C. elegans and imaged at low concentrations of ∼0.16 μg mg−1.

Determination of Nucleotide Sequences within Promoter Regions Affecting Promoter Compatibility between Zymomonas mobilis and Escherichia coli.

A promoter plays a crucial role in controlling the expression of the target gene in cells, thus being one of the key biological parts for synthetic biology practices. Although significant efforts have been made to identify and characterize promoters with different strengths in various microorganisms, the compatibility of promoters within different hosts still lacks investigation. In this study, we chose the native Pgap promoter of Zymomonas mobilis to investigate nucleotide sequences within promoter regions affecting promoter compatibility between Escherichia coli and Z. mobilis. Pgap is one of the strongest promotors in Z. mobilis that has many excellent characteristics to be developed as microbial cell factories. Using EGFP as a reporter, a Z. mobilis-derived Pgap mutant library was constructed and sorted in E. coli, with candidate promoters exhibiting high fluorescence intensity collected. A total of 53 variants were finally selected and sequenced by Sanger sequencing. The sequencing results grouped these variants into 12 different Pgap variant types, among which seven types presented higher promoter strength than native Pgap in E. coli. The next-generation sequencing technique was then employed to identify key mutations within the Pgap promoter region that affect the promoter compatibility. Finally, six important sites were identified and confirmed to help increase Pgap strength in E. coli while keeping similar strength of native Pgap in Z. mobilis. Compared to native Pgap, synthetic promoters combining these sites had enhanced strength; especially, Pgap-6M combining all six sites exhibited 20-fold greater strength than native Pgap in E. coli. This study thus not only determined six important sites affecting promoter compatibility but also confirmed a series of Pgap promoter variants with strong promoter activity in both E. coli and Z. mobilis. In addition, a strategy was established in this study to investigate and determine nucleotide sequences in promoter regions affecting promoter compatibility, which can be applied in other microorganisms to help reveal universal factors affecting promoter compatibility and design promoters with desired strengths among different microbial cell factories.

Facile off-on fluorescence biosensing of human papillomavirus using DNA probe coupled with sunflower seed shells carbon dots

We report a fluorescent “off-on” platform based on carbon dots (CDs) and DNA probe to achieve trace detection of human papillomavirus 16 (HPV 16). Initially, the CDs was synthesized by simple two-step method, using biomass sunflower seed shells as precursor, doped with L-arginine and passivated by polyethyleneimine (PEI) to obtain positively charged biomass CDs that had the merits of high fluorescence intensity, green synthesis and good stability. Then, the DNA probe was prepared by modifying single-stranded DNA (ssDNA) with 4-(4-dimethylaminobenzazo) benzoyl (Dabcyl) fluorescence quenching agent. Due to electrostatic effect and Förster resonance energy transfer (FRET) mechanism, DNA probe can cause fluorescence quenching of the prepared CDs. Since HPV 16 bound to the DNA probe followed a strict base complementation pairing rule, it turned on the fluorescence of CDs by separating the DNA probe from the CDs. The limit of detection (LOD = 0.47 nM) and the linear range (0.5–150 nM) of the probe for HPV 16 were favorable. The recovery of HPV 16 in urine and cervical swabs were 96.6%-113.3% and 95.7%-103.9%. This method can achieve highly specific detection of the DNA sequences of target virus without complicated operation and expensive equipment, which is of great significance for biochemical analysis.

Aromatic Amino Acid-Mediated Perovskite Nanocrystals: Fluorescence Tuning and Morphological Evolution.

Lead halide perovskites with high fluorescent and tunable morphology appeared at the forefront of materials chemistry because of their corresponding impressive optoelectronic properties. The current advancement of metal halide perovskites put forward the functional and bidentate ligand to expand their utilization in modified ligand chemistry. We successfully introduced nontoxic aromatic amino acid as a capping ligand to synthesize the perovskite nanocrystals (PNCs). The implementation of aromatic amino acid for the construction of CsPbX3 nanocrystals (NCs) provides the synergetic service of the carboxylic and amine groups with the phenyl residue, which prompts the formation of NCs with high fluorescence intensity. The experimental results demonstrate the emissive property of PNCs in a whole visible region with long-term stability. Additionally, the morphology of the NCs has been tuned. We performed several characterization techniques to investigate the nature of the NCs in the solid and solution phases.

Successful desensitization of high level donor-specific anti-HLA antibody in patients with hematological diseases receiving haploidentical allografts.

Donor-specific anti-human leukocyte antigen (HLA) antibody (DSA) is associated with a higher incidence of graft failure and mortality in HLA-mismatched allograft settings. However, the optimal protocol of desensitization for patients with positive DSA remains uncertain. We investigated the effectiveness of a desensitization protocol, including rituximab, high-dose intravenous immunoglobulin (IVIG), and a single session of plasma exchange (PE), for haploidentical allograft recipients with a high mean fluorescence intensity (MFI) level of DSA (≥ 5,000). Eleven patients with hematological disease who had positive DSA (median, 11,676, range 5387-20,435) were desensitized by the protocol. All of the patients achieved hematopoietic recovery. The median times for neutrophil and platelet engraftment were 13 (range, 11-26) days and 19 (range, 11-90) days, respectively. Grade II-IV acute graft-versus-host disease (GVHD) was seen in one patient and was controlled completely. Chronic cutaneous GVHD was seen in eight patients. Nine patients are alive with good performance so far. One patient suffered extramedullary relapse, and one patient died of transplantation-associated thrombotic microangiopathy. The 1-year probability of overall survival was 81.8%. These results suggest that successful desensitization could be obtained by a combination of rituximab, high-dose IVIG, and PE for haploidentical allograft recipients with high MFI levels of DSA.

Abstract 5702: Cancer-specific glycosylation regulated by epigenomic alteration in renal cell carcinoma

Abstract Background and Aims: Cancer-specific glycosylation plays an important role in the development and progression of cancer. Epigenetics may contribute to forming cancer-specific glycosylation by regulating the expression of glycogenes. Although comprehensive analysis of epigenetics is routinely performed, comprehensive glycan analysis, especially using human clinical samples, has been limited due to technical underdevelopment. Our aims are to understand the significance of glycosylation and its epigenetic regulation on renal carcinogenesis and to identify cancer-specific glycosylation as a potential diagnostic marker and a novel therapeutic target. Materials and Methods: Comprehensive glycomics and methylome analysis were performed by lectin microarray and Infinium HumanMethylation450 BeadChip on 50 non-cancerous renal cortex tissue (N) and 50 clear cell renal cell carcinoma (RCC) (T) microdissected from formalin-fixed and paraffin-embedded tissue samples. Results: Compared to N samples, T samples showed higher fluorescence intensity for lectins recognizing mannose-type glycans, and lower intensity for lectins recognizing sialyl and fucosyl groups. In RCC, the metabolism of N-glycans may remain in an immature state. By hierarchical clustering using lectin microarray data, T samples were divided into Clusters A and B with significant differences in patients’ outcome. Increased high-mannose type N-glycan and core fucosylation and decreased sialylation were observed in T samples of Cluster A. According to these results, glycosylation profiles showed heterogeneity associated with patients’ outcome among RCCs, and immature N-glycan may be specific in some RCCs. Methylome analysis suggests that specific glycosylation profiles of RCCs may be induced by DNA methylation alteration on glycogenes. Association between DNA methylation and mRNA expression was confirmed on some glycogenes using real-time reverse transcription PCR. As a result of examining whether the signal intensity pattern of each lectin reflects the prognosis of clear cell RCC, we could identify the lectins that reflect the RCCs prognosis. Conclusion: In RCC, the metabolism of N-glycans may remain in an immature state. The glycan profiles show heterogeneity among individual RCCs, and some of the specific glycan profiles may be associated with patients’ outcome. Cancer-specific glycan profiles may be regulated by epigenetic alteration of glycogenes. Citation Format: Yoshiko Kitazume, Eri Arai, Atsushi Matsuda, Kentaro Ohara, Akiko Miyagi Maeshima, Teruhiko Yoshida, Atsushi Kuno, Yae Kanai. Cancer-specific glycosylation regulated by epigenomic alteration in renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5702.

Abstract 4047: Targeted liposomes against ovarian cancer

Abstract Purpose: Cisplatin (CPT) is a first-line chemotherapeutic agent for the treatment of ovarian cancer. However, CPT has severe adverse effects. The purpose of this study is to develop targeted liposomes that selectively target the xCT transporter which is upregulated in ovarian cancer and carry CPT to ovarian cancer only, thereby avoiding the adverse effects of CPT. We evaluated the stability, the cytotoxicity and the cellular uptake of targeted liposomes in ovarian cancer cell lines. Methods: CPT was encapsulated by the remote loading method in liposomes. The stability of liposomes was evaluated by measuring the drug-leakage from liposomes and the growth of liposome size stored at 4°C and room temperature over a 30-day period. For the drug-leakage study, liposomes were placed into a dialysis tubing and dialysate aliquots were removed and analyzed twice weekly for CPT content. The liposome size was evaluated using Dynamic Light Scattering (Nano Brook Omni, Brookhaven Instruments). The cellular uptake of targeted liposomes (encapsulating the fluorescent dye sulforhodamine B, SRB) was evaluated in drug-resistant (A2870cis, OVCAR3, OVCAR4, IGROV1, and NCI/ADR-RES) and drug sensitive (A2870 and OVCAR8) ovarian cancer cell lines (purchased from the NIH), were evaluated using flow cytometry (BD Accuri C6). The cytotoxicity of CPT in targeted liposomes was evaluated in the various ovarian cell lines using the MTS assay (Novus Biologicals). Results: The targeted liposomes over the 30-day period, show that 6.8% of the total loaded CPT leaked out of the liposomes. During that period the growth of the liposomes was <5% for the liposomes stored at 4°C and <1% of their initial size, stored at 25°C. The cellular uptake of ovarian cancer cell lines, A2870, A2870cis, OVCAR3, OVCAR4, OVCAR8, and NCI/ADR-Res the targeted SRB loaded liposomes showed significantly more fluorescence intensity when compared to free SRB and non-targeted liposomes (p<0.05). In the cell line IGROV1, there is a similar trend seen, where there was a higher fluorescence intensity compared to free SRB and non-targeted. The fluorescence intensity was found to be higher compared to non-targeted liposomes (p<0.0001) but not statistically significant higher compared to free SRB. For cytotoxicity, a similar trend is seen in cell lines A2870, A2870cis, IGROV1, OVCAR3, OVCAR4, OVCAR8, and NCI/ADR-res, where the cisplatin loaded targeted liposomes had the lowest IC50 compared to free drug and non-targeted liposomes. Non-targeted liposomes had the highest IC50 values compared to free drug and targeted liposomes. In cell lines A2870, A2870cis, IGROV1, OVCAR3, OVCAR4, OVCAR8, and NCI/ADR-res the IC50 values show a 2.4, 5.3, 4.1, 3.3, 1.7, 1.6, and 2.5-fold lower values compared to free cisplatin, respectively. Conclusion: Targeted liposomes encapsulating CPT show stability, enhanced in-vitro cellular uptake and anti-cancer activity in resistant and sensitive ovarian cancer cell lines. Citation Format: Antonia Marashio, Maria (Mary) P. Lambros, Adenike Oyegbesan. Targeted liposomes against ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4047.

Lanthanide (Eu3+/Tb3+)-Loaded γ-Cyclodextrin Nano-Aggregates for Smart Sensing of the Anticancer Drug Irinotecan.

The clinical use of anticancer drugs necessitates new technologies for their safe, sensitive, and selective detection. In this article, lanthanide (Eu3+ and Tb3+)-loaded γ-cyclodextrin nano-aggregates (ECA and TCA) are reported, which sensitively detects the anticancer drug irinotecan by fluorescence intensity changes. Fluorescent lanthanide (Eu3+ and Tb3+) complexes exhibit high fluorescence intensity, narrow and distinct emission bands, long fluorescence lifetime, and insensitivity to photobleaching. However, these lanthanide (Eu3+ and Tb3+) complexes are essentially hydrophobic, toxic, and non-biocompatible. Lanthanide (Eu3+ and Tb3+) complexes were loaded into naturally hydrophilic γ-cyclodextrin to form fluorescent nano-aggregates. The biological nontoxicity and cytocompatibility of ECA and TCA fluorescent nanoparticles were demonstrated by cytotoxicity experiments. The ECA and TCA fluorescence nanosensors can detect irinotecan selectively and sensitively through the change of fluorescence intensity, with detection limits of 6.80 μM and 2.89 μM, respectively. ECA can safely detect irinotecan in the cellular environment, while TCA can detect irinotecan intracellularly and is suitable for cell labeling.

Enantioselective fluorescent detection of lysine enantiomers by functionalized achiral metal organic frameworks

In this work, achiral metal organic frameworks (MIL-53(Al)–NH2) were synthesized and functionalized with poly (amidoamine) (PAMAM) dendrimers. By dispersing PAMAM grafted MIL-53(Al)–NH2 to water, the obtained solution exhibited high fluorescence intensity and stability. Due to the strong affinity interaction, fluorescence of the solution was quenched when Cu2+ was added. Following the addition of lysine to the system, the quenched fluorescence intensity was partially restored based on the chelation between Cu2+ and lysine. In this case, the fluorescent signal of MIL-53(Al)–NH2-PAMAM-Cu2+ system became turn-on state. Furthermore, because of different chelating abilities with L-lysine and D-lysine, the system exhibited enantioselective fluorescence enhancement. Therefore, the PAMAM grafted MIL-53(Al)–NH2 were successfully used for enantioselective fluorescence detection of lysine after being quenched by Cu2+. The method showed good linearity in both L/D-lysine detection (R2 = 0.9976–0.9984) and ee values determination (R2 = 0.9921). The detection limit of L-lysine and D-lysine were 7.52 and 12.2 μmol L−1, respectively. Reliability of the method was verified by analysis of lysine enantiomers in spiked drinking water samples. Rapid enantioselective fluorescent imaging of lysine enantiomers showed great application prospects in test paper, diagnostic kit and vivo imaging system.

Synthesis and characterization of some novel polythiophene derivatives containing pyrazoline

ABSTRACT Eight polythiophene derivatives containing pyrazoline side groups were synthesized by a chemical oxidative coupling polymerization using FeCl3. The crystal structures of four monomers were determined which confirm the almost perpendicular orientation of the thiophene and pyrazoline rings, while the other substituents are more coplanar. Analyses of IR, 1H-NMR, Raman and UV-Vis spectra demonstrated that the suggested polymerization was successful to generate the synthesized polythiophenes with the expected structures. The morphology of the synthesized polythiophenes was studied by SEM. The different substituents attached to the 1- and 3-positions of the pyrazoline side chain led to differences in optical properties, electrical conductivity, and thermal stability of the synthesized polythiophenes. By adding a pyrazoline side chain to polythiophenes, some polymers achieve good solubility, electrical conductivity of about 1.3 × 10–6 S/cm, high fluorescence intensity (above 40,000 a.u.) at 505–550 nm and thermal stability up to 590°C in the air.

Preparation and fluorescence properties of MgAl2O4: Tb3+ nanorod-like phosphors

A series of MgAl2O4: x% Tb3+ (x = 1.0–6.0) phosphors was prepared by a hydrothermal-assisted light burning method. The crystal structure, morphology and fluorescence properties of the samples were investigated. The results indicated that when the the hydrothermal and light burning temperatures were determined to be 120 °C and 1100 °C, respectively, the crystallinity for Mg4Al2(OH)14 and NH4Al(OH)2CO3 biphasic precursors is the best, conducive to generating pure phase MgAl2O4 nanorod-like phosphors. The entry of Tb3+ into the MgAl2O4 lattice can cause lattice distortion, but the main structure of the spinel does not change. The main emission peaks for the series of phosphors are located in the green light region of 546 nm. The MgAl2O4: 4.0% Tb3+ phosphor has the highest fluorescence intensity and shows the best colour quality. Its CIE coordinates (x, y), CCT and colour purity are determined to be (0.3171, 0.5290), 5845 K and 53.50%, respectively. The series of MgAl2O4: Tb3+ phosphors exhibits typical cold green light emission and have good application prospects in solid-state display devices.