Preparation of Cholesteryl-Modified Aminated Pullulan Nanoparticles to Evaluate Nanoparticle of Hydrophobic Degree on Drug Release and Cytotoxicity

The formation of nanoparticles (NPs) and surface properties such as size and charge are affected by the amphiphilic property of polymer, which is vital for evaluating their function. Here, we synthesized cholesteryl-modified aminated pullulan polymers (CHPNs) with different amounts of cholesterol succinate (CHS). We characterized the three hydrophobically modified polymers (CHPN1, CHPN2, and CHPN3) (CHS: Pu‐NH2=1/5,2/5,3/5) by Fourier transform infrared spectrometry. Dynamic light scattering (DLS) was used to measure particle size and zeta potential of CHPN NPs. The particle sizes of the three NPs CHPN1, CHPN2, and CHPN3 were 178.0, 144.4, and 97.8 nm, respectively. The particle size was related to the cholesteryl substitution of polymers to a certain extent: the stronger the hydrophobicity, the smaller the particle size. In 48 h, the drug release for CHPN3 and CHPN1 NPs was 57.8% and 72.7%. Thus, the NPs showed good sustained drug release: the greater the degree of hydrophobic substitution, the better the sustained release. The cytotoxicity findings were reversed: CHPN1 NPs, with low hydrophobic substitution, showed the best inhibition of Lewis lung cancer cells.

LTCC MICROREACTORS APPLICATION IN A MICROFLUIDIC INTEGRATED SYSTEM FOR HYDROPHOBIC DRUG ENCAPSULATION IN POLYMERIC NANO/MICROPARTICLES

Nanotechnology develops methods and processes for Drug Delivery Systems (DDS) based on the fabrication of polymeric nano/microparticles with encapsulated drug that can be applied for maximize therapeutic activity and minimizes undesirable effects. However, these processes entail several conditions to operate efficiently. They present high sensibility to changes in temperature, flow rate, pressure, and chemical solution composition. An optimal configuration of these parameters is required to guarantee stable particle production. For these reasons, integration of technological devices like sensors, actuators, microfluidic devices and control systems is essential to increase particle production performance. The proposal of this work is to develop an integrated monitored and controlled system using LTCC (Low Temperature Co-Fired Ceramic) microreactors to generate polymeric nano/microparticles for encapsulation of hydrocortisone drug with PCL and Pluronic polymers. The microfluidic integrated system is developed through devices integration, system characterization and control loops configuration, using pressure sensors, syringe and microgear pumps, mixer and vortex LTCC microfluidic reactors, communication drivers, and data processing/control programs. Dynamic Light Scattering, Optical and Scanning Electron Microscopy were employed to measure particle size, polydispersity (PdI) distribution and particle morphology. Preliminary results showed nano/microparticles with encapsulated hydrocortisone drug having a mean diameter size of 528–816 nm and Polidispersity Index (PdI) < 0.5.

A Combined Reverse Fourier Set-Up for Laser Particle Size Measurement

A combined reverse Fourier set-up was presented on Fresnel diffraction theory. The set-up was used to measure particle size distribution with laser. A particle sample is set back of a lens. A first detector array is set in the focus plane of the lens. A second lens and a second detector array are set behind the first detector and the combined focus plane of the two lenses in turn. Thus the measurable size range at on sampling is enlarged. Experimental results on some latex samples by the prototype show that the relative errors are less than 6%.

The unique properties of agricultural aerosols measured at a cattle feeding operation

Housing roughly 10 million head of cattle in the United States alone, open air cattle feedlots represent a significant but poorly constrained source of atmospheric particles. Here we present a comprehensive characterization of physical and chemical properties of particles emitted from a large representative cattle feedlot in the Southwest United States. In the summer of 2008, measurements and samplings were conducted at the nominally upwind and downwind edges of the facility. A series of far-field measurements and samplings was also conducted 3.5 km north of the facility. Two instruments, a GRIMM Sequential Mobility Particle Sizer (SMPS) and a GRIMM Portable Aerosol Spectrometer (PAS), were used to measure particle size distributions over the range of 0.01 to 25 μm diameter. Raman microspectroscopy (RM) was used to determine the chemical composition of particles on a single particle basis. Volume size distributions of fugitive dust were dominated by coarse mode particles. Twenty-four hour averaged concentrations of PM10 (particulate matter with a diameter of 10 μm or less) were as high as 1200 μg m−3 during the campaign. The primary constituents of the particulate matter were carbonaceous materials, such as humic acid, water soluble organics, and less soluble fatty acids, including stearic acid and tristearin. A significant percentage of the organic particles, up to 28 %, were composed of internally mixed with salts. Basic characteristics such as size distribution and composition of agricultural aerosols were found to be different than the properties of those found in urban and semi-urban aerosols. Failing to account for such differences will lead to serious errors in estimates of aerosol effects on climate, visibility, and public health.

The Effect of Time of Powder Removal on Powder Particle Size and Shape Copper Powder Produced by Electrolysis Method

In this study, electrolyze unit, which is used for the production of metal powders, was designed and produced. The production of powder was carried out by using different parameter times of powder removal (5, 10, 20, 30 and 40 min.). The effect of time of powder removal on powder particle size and shape was examined. Laser particle measurement machine and SEM were also used to measure particle size and particle shape respectively. Experimental results indicated that an increase in time of powder removal caused an increase in powder particle size and its shape changed from acicular dentritic to globular dentritic.