ABSTRACT
Objective:To investigate the factors that could influence the particle size and size distribution of mRNA vaccines.Methods:The influences of several factors including the ionic strength and pH values of buffers, solutions, dilution folds and testing equipments on the particle size and size distribution of three batches of mRNA vaccines were analyzed by dynamic light scattering.Results:The particle size increased with increasing ionic strength, but no significant change in size distribution was observed. The particle size also increased with increasing pH values and the size distribution showed significant change when the buffer solution was weakly alkaline. Solution types could affect the particle size, but had no influence on size distribution. There was no significant change in the particle size or size distribution when the dilution was limited to 100 folds. Moreover, the particle size and size distribution detected by different equipments showed no significance difference.Conclusions:The particle size and size distribution of mRNA vaccines could be affected by solution, dilution fold and testing equipment, which should be concerned during the vaccine production and quality control.
ABSTRACT
Photothermal therapy has the characteristics of minimal invasiveness, controllability, high efficiency, and strong specificity, which can effectively make up for the toxic side effects and tumor resistance caused by traditional drug treatment. However, due to the limited tissue penetration of infrared light, it is difficult to promote and apply in clinical practice. The eye is the only transparent tissue in human, and infrared light can easily penetrate the eye tissue, so it is expected that photothermal therapy can be used to treat fundus diseases. Here in, a new nano-platform assembled by liposome and indocyanine green (ICG) was used to treat retinoblastoma. ICG was assembled in liposomes to overcome some problems of ICG itself. For example, ICG is easily quenched, self-aggregating and instability. Moreover, liposomes can prevent free ICG from being cleared through the systemic circulation. The construction of the nano-platform not only ensured the stability of ICG in vivo, but also realized imaging-guide photothermal therapy, which created a new strategy for the treatment of retinoblastoma.
ABSTRACT
This study aimed to explore the link between block copolymers' interfacial properties and nanoscale carrier formation and found out the influence of length ratio on these characters to optimize drug delivery system. A library of diblock copolymers of PEG-PCL and triblock copolymers with additional PEI (PEG-PCL-PEI) were synthesized. Subsequently, a systematic isothermal investigation was performed to explore molecular arrangements of copolymers at air/water interface. Then, structural properties and drug encapsulation in self-assembly were investigated with DLS, SLS and TEM. We found the additional hydrogen bond in the PEG-PCL-PEI contributes to film stability upon the hydrophobic interaction compared with PEG-PCL. PEG-PCL-PEI assemble into smaller micelle-like (such as PEG-PCL4006-PEI) or particle-like structure (such as PEG-PCL8636-PEI) determined by their hydrophilic and hydrophobic block ratio. The distinct structural architectures of copolymer are consistent between interface and self-assembly. Despite the disparity of constituent ratio, we discovered the arrangement of both chains guarantees balanced hydrophilic-hydrophobic ratio in self-assembly to form stable construction. Meanwhile, the structural differences were found to have significant influence on model drugs incorporation including docetaxel and siRNA. Taken together, these findings indicate the correlation between molecular arrangement and self-assembly and inspire us to tune block compositions to achieve desired nanostructure and drug loading.
ABSTRACT
Background: A simple and efficient strategy for agarase immobilization was developed with carboxyl-functionalized magnetic nanoparticles (CMNPs) as support. The CMNPs and immobilized agarase (agarase-CMNPs) were characterized by transmission electron microscopy, dynamic light scattering, vibrating sample magnetometry, scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and zeta-potential analysis. The hydrolyzed products were separated and detected by ESI-TOF-MS. Results: The agarase-CMNPs exhibited a regular spherical shape with a mean diameter of 12 nm, whereas their average size in the aqueous solution was 43.7 nm as measured by dynamic light scattering. These results indicated that agarase-CMNPs had water swelling properties. Saturation magnetizations were 44 and 29 emu/g for the carriers and agarase-CMNPs, respectively. Thus, the particles had superparamagnetic characteristics, and agarase was successfully immobilized onto the supports. Agaro-oligosaccharides were prepared with agar as substrate using agarase-CMNPs as biocatalyst. The catalytic activity of agarase-CMNPs was unchanged after six reuses. The ESI-TOF mass spectrogram showed that the major products hydrolyzed by agarase-CMNPs after six recycle uses were neoagarotetraose, neoagarohexaose, and neoagarooctaose. Meanwhile, the end-products after 90 min of enzymatic treatment by agarase-CMNPs were neoagarobiose and neoagarotetraose. Conclusions: The enhanced agarase properties upon immobilization suggested that CMNPs can be effective carriers for agarase immobilization. Agarase-CMNPs can be remarkably used in developing systems for repeated batch production of agar-derived oligosaccharides.
Subject(s)
Oligosaccharides/metabolism , Enzymes, Immobilized , Magnetite Nanoparticles/chemistry , Glycoside Hydrolases/metabolism , Thermogravimetry , X-Ray Diffraction , Enzyme Stability , Catalysis , Microscopy, Electron, Transmission , Magnetometry , Dynamic Light Scattering , Glycoside Hydrolases/chemistryABSTRACT
A gold nanoparticle ( GNP)-based dynamic light scattering ( DLS) assay has been developed for detecting mercury ion ( Hg2+) in aqueous solution. The GNPs are able to maintain monodisperse state in relative high ionic strength ( 0. 1 mol/L NaCl ) aqueous solution because Hg2+ aptamer 5’-TTTCTTCTTTCTTCCCCCCTTGTTTGTTGTTT-3’( Probe DNA ) can adsorb on the GNP surface by electrostatic interaction. In the presence of Hg2+, the Probe DNA molecules easily desorb from GNP surface because of T-Hg2+-T formation. The unprotected GNPs form aggregates in 100 mmol/L NaCl solution, resulting in increased significantly the average hydrodynamic diameter of GNPs. Under the conditions of pH 7. 43, 110 nmol/L aptamer, 100 mmol/L NaCl and 30 minutes incubation time of Hg2+with aptamer, the difference of average hydrodynamic diameter (△D ) of GNPs was increased linearly with logarithm of Hg2+concentration over the range from 0. 1 nmol/L to 5 μmol/L, with a detection limit of 0. 1 nmol/L. Moreover, satisfactory results were obtained when the proposed method was applied to detect Hg2+ in real samples.
ABSTRACT
A systematic investigation of interaction of multi-carbon nanoparticles, obtained from soot, with dipalmitoyl phosphatidylcholine (DPPC), a clinical pulmonary phospholipid surfactant, sold under trade name “Survanta”, was undertaken to establish a model for internalization of these nanoparticles inside alveolar cavity. In vitro experiments were carried out to establish the phospholipid assisted dispersion mechanism of carbon nanoclusters (size 150 nm, zeta potential -15 mV) in water. Results obtained from an array of experimental methods, like dynamic laser light scattering, electrophoresis, UV-absorption spectroscopy, surface tension studies and transmission electron microscopy, revealed that the carbon nanoparticles interacted with DPPC predominantly via hydrophobic interactions. Selective surface adsorption of DPPC molecules on nanoparticle surface was found to be strongly dependent on the concentration of the phospholipid. DPPC, a gemini surfactant, formed a rigid monolayer around the carbon nanocluster even at nanomolar concentration and provided excellent stability to the dispersion. Based on the experimental data it is proposed that the free-energy gain involved in the hydrophobic interactions will facilitate the internalization of these nanoparticles on the inner wall of the alveolar cavity.
ABSTRACT
The magnetic nanoparticle probe was prepared by specifically connecting the streptavidin-conjugated magnetic nanoparticles and the antibody of analyte via the strong streptavidin-biotin interaction. Based on the magnetic nanoparticle probes, the concentration of human chorionicgonadotropin (HCG) was detected and a new CL method for of hormone was further established. The performances of the magnetic nanoparticle probes were characterized by UV-Vis spectrometry, transmission electron microscopy and dynamic light scattering. The experimental conditions that affected the chemiluminescence were optimized. The optimal concentrations of luminal and H_2O_2 were 2×10~(-4) mol/L and 8×10~(-4) mol/L, respectively, and optimal pH was 13. Under the optimized experiment conditions, a linear response of chemiluminescence intensity to HCG concentration was obtained with a correlation coefficients of 0.9924. The linear range was from 0.5 to 250 μg/L and wider than the conventional ELISA method (5-200 μg/L). The relative standard deviation was 3.8%. Correlation analysis showed that there was significant correlation between the method of magnetic nanoparticle probes and ELISA in 34 clinical samples. The proposed method with characters of sensitive, effective, fast response and wide detection range provided good application prospect in analysis of other ultra-micro protein.