Improvement Of Fluorescence Intensity Research Articles

Functional, physicochemical, and rheological properties of the spray drying particles prepared from the noble scallop (Chlamys nobilis) mantle protein‐pectin hydrated mixtures

SummaryThe present study aimed to comparatively analyse the functional properties of the spray drying particles prepared from the noble scallop (Chlamys nobilis) mantle protein‐pectin hydrated mixtures. And the microstructural characteristics of the particles were assessed by Fourier transform infrared, scanning electronic microscopy, and SDS‐PAGE to detect critical changes. The results showed that the solubility of enzymatically extracted protein was significantly improved by spray drying after pectin hydration (AP‐LMP and AP‐HMP), from 76.77% (AP) to 97.87% (AP‐LMP) and 97.13% (AP‐HMP), respectively. And the spray drying water‐extracted protein (HP) after pectin hydration (HP‐LMP and HP ‐HMP) exhibited a greater emulsifying property, from 103.10 m2/g (HP) to 145.55 ± 0.92 m2/g (HP‐LMP) and 200.29 ± 1.16 m2/g (HP‐HMP). The spray drying after pectin hydration had successfully enhanced emulsifying and rheological properties when compared with AP and HP. The results of SDS‐PAGE showed more protein participated in the formation of macromolecule and FT‐IR spectra demonstrated the formation of protein‐pectin spray drying particles facilitated not only by electrostatic interactions but also by covalent binding via Maillard reaction, made a closely compatible protein structure verified by the improvement of fluorescence intensity. This work is expected to provide a theoretical basic data for the development and application of scallop mantle extracted proteins.

The Impact of Covalent Functionalization on Single-Walled Carbon Nanotube Biosensor Fluorescence and Function

Single-walled carbon nanotubes (SWCNTs) are advantageous signal transduction elements for biological imaging and sensing due to their notable fluorescence in the near-infrared (NIR) region with minimal light absorbance by water or scattering by tissue (1). Recently, exciting developments in SWCNT surface chemistry have shown the retention and improvement of fluorescence intensity in SWCNTs after covalent surface functionalization (2). These chemistries provide chemical handles for specific attachment of molecules of interest to the SWCNT surface while keeping the intrinsic SWCNT NIR fluorescence intact for bioimaging and sensing applications. However, despite their unperturbed fluorescence, it is unclear whether functionalized SWCNTs maintain their ability for molecular sensing, which necessitates a modulation in SWCNT fluorescence provided by the molecular recognition of a noncovalently surface-adsorbed polymer. We compare the photophysical properties of functionalized SWCNTs to their pristine counterparts, and show SWCNT optical properties remain available for sensing applications, however with noted attenuation of fluorescence modulation between certain surface coating and analyte pairs. Molecular recognition provided by phospholipid SWCNT surface coatings maintain their ability to detect molecular analytes such as fibrinogen and insulin. Conversely, DNA oligonucleotide surface coatings under-perform for molecular recognition of dopamine compared to sensors constructed from pristine SWCNTs. We also discuss the use of covalent handles to tune the intrinsic properties of the SWCNT surface for use as biological tools. Lastly, we explore the application of covalently functionalized SWCNTs as dual-functional nanoparticles with both targeting and sensing capabilities. Our work establishes the potential advantages and drawbacks of covalent SWCNT functionalization, despite preservation of SWCNT fluorescence, and implications for applications in molecular sensing.(1) Bonis-O’Donnell, J. T. D.; Page, R. H.; Beyene, A. G.; Tindall, E. G.; McFarlane, I. R.; Landry, M. P. Dual Near-Infrared Two-Photon Microscopy for Deep-Tissue Dopamine Nanosensor Imaging. Adv. Funct. Mater. 2017, 27 (39), 1–10.(2) Setaro, A.; Adeli, M.; Glaeske, M.; Przyrembel, D.; Bisswanger, T.; Gordeev, G.; Maschietto, F.; Faghani, A.; Paulus, B.; Weinelt, M.; et al. Preserving π-Conjugation in Covalently Functionalized Carbon Nanotubes for Optoelectronic Applications. Nat. Commun. 2017, 8, 1–7.

Regulatory elements in vectors containing the ctEF-1\u03b1 first intron and double enhancers for an efficient recombinant protein expression system

To establish a stable and scalable transient protein production system, we modified the EF-1 first intron size and verified the order of two recombinant enhancers downstream of the SV40 polyA sequence. This new vector was named pHH-Gemini (pHH-GM1) and was used to express alpha kinase 1 (ALPK1) and various other proteins, NLRP3, F-actin, Camodulin, PP2A, URAT1, Rab11a and myosin IIA. The results showed that, compared with six commercial plasmids, pHH-GM1 significantly enhanced His-HA-ALPK1 expression in a western blot analysis of transfected HEK293T cells. The expression of various other genes was also successful using the pHH-GM1 vector. In addition, we inserted turbo green florescence protein (tGFP) into the pHH-GM1 vector, and an improvement in fluorescence intensity was observed after transient transfection of HEK293T cells. For large-scale production, protein production was tested by standard supplementation with one volume of medium, and volumetric yields of 2 and 2.3 mg/L were achieved with pHH-GM1-ALPK1 in HEK293-F and CHO-S cells, respectively. We found that cell viability was more than 70% 11 days after cells were transfected with the pHH-GM1 vector. The pHH-GM1 vector with the ctEF-1α first intron and double enhancers, Simian virus 40 and Cytomegalovirus (SV40 and CMV) is an efficient CMV promoter-based gene expression system that can potentially be applied to study genes of interest and improve protein production.

Novel 4-amino-2-methyl-8-(trifluoromethyl)quinoline-based magnetic nanostructures for highly sensitive detection of zinc ions in aqueous solutions

Novel 4-amino-2-methyl-8-(trifluoromethyl)quinoline based magnetic nanosensors, Fe3O4@SiO2-PEG-4AQ and Fe3O4@SiO2-4AQ, were successfully fabricated and characterised. Enhanced fluorescent intensity was demonstrated by both nanosensors. Upon complexation with zinc ions, a further enhancement of 13.5-fold was revealed by Fe3O4@SiO2-PEG-4AQ. A red shift of 42 nm was also observed. The presence of other metal cations including Ni2+, Co2+, Ca2+, Cd2+, Hg2+, Mg2+, Mn2+ and Ag+, showed no interference towards Zn2+. A sensitive detection limit of 0.0065 μM and 0.0125 μM was indicated by Fe3O4@SiO2-PEG-4AQ and Fe3O4@SiO2-4AQ respectively. The high sensitivity and selectivity remained constant within a wide range of pH values and were reversible upon treatment with EDTA. The PEG spacer between the magnetic core and the fluorophore offered further improvement of fluorescence intensity and detection sensitivity. To the best of our knowledge, this is the first study on 4-aminoquinoline based reusable nanochemosensor for zinc ion detection.

Effects of different ultrasound power on physicochemical property and functional performance of chicken actomyosin

The aim of present study was to investigate the effect of different ultrasound power on physicochemical property and functional performance of chicken actomyosin (CAM). The treated CAM had the lowest particle size and the highest absolute zeta potential at 150 W. The conformation changes of treated CAM exhibited the reduction in α-helix as well as the improvement of fluorescence intensity. Ultrasound power at 150 W could significantly increase protein hydrophobicity and reactive SH groups compared to the others (P < 0.05). The disappearance of specific peaks and lower endothermic peaks implied that the treated CAM became thermally instable. The microstructure of CAM revealed small and homogeneous sub-bunches treated by 100–150 W. Furthermore, the solubility and emulsion property of CAM was significantly increased at 150 W (P < 0.05). These results demonstrated that ultrasound treatment at the power of 100–150 W may be an appropriate range to modify CAM for enhancing its functional properties.

Improvement of fluorescence intensity of nitrogen vacancy centers in self-formed diamond microstructures

We present umbrella-shaped diamond microstructures with metal mirrors at the bottom in order to improve the amount of collected photons from nitrogen vacancy centers. The metal mirrors at the bottom are self-aligned to the umbrella-shaped diamond microstructures which are selectively grown through holes created on a metal mask. By the finite-difference time-domain simulations, we found that the umbrella-shaped microstructures, which have an effect similar to solid immersion lens, could collect photons more efficiently than bulk or pillar-shaped microstructures. Improvement of the fluorescence intensity by factors of from 3 to 5 is shown experimentally.

The Influence of SiO2 Shell on Fluorescent Properties of LaF3:Nd3+/SiO2 Core/Shell Nanoparticles

Distinct effects of the SiO2 shell on fluorescence properties of LaF3:Nd3+/SiO2 core/shell nanoparticles were demonstrated by annealling the nanoparticles at different temperatures. Emission spectra, excitation spectra, and decay curves of the nanoparticles were measured. A significant improvement of fluorescence intensity was observed for LaF3:Nd3+/SiO2 core/shell nanoparticles annealed at 900 ∘C. The phenomenon is ascribed to the change of environment of LaF3:Nd3+ core which is imposed by SiO2 shell. And the change is confirmed by the excitation spectra. It provides a useful way to improve fluorescent intensity of the SiO2‐coated LaF3:Nd3+ nanoparticles. The lifetime for nanoparticles annealed at 900 ∘C shows a slight decrease contrast with nanoparticles annealed at 400 and 600 ∘C. This is caused by the higher phonon energy of SiO2 than that of LaF3.