Qualitative Analysis of Dairy and Powder Milk Using Laser-Induced Breakdown Spectroscopy (LIBS).

Laser-induced breakdown spectroscopy (LIBS) technique was used to compare various types of commercial milk products. Laser-induced breakdown spectroscopy spectra were investigated for the determination of the elemental composition of soy and rice milk powder, dairy milk, and lactose-free dairy milk. The analysis was performed using radiative transitions. Atomic emissions from Ca, K, Na, and Mg lines observed in LIBS spectra of dairy milk were compared. In addition, proteins and fat level in milks can be determined using molecular emissions such as CN bands. Ca concentrations were calculated to be 2.165 ± 0.203 g/L in 1% of dairy milk fat samples and 2.809 ± 0.172 g/L in 2% of dairy milk fat samples using the standard addition method (SAM) with LIBS spectra. Univariate and multivariate statistical analysis methods showed that the contents of major mineral elements were higher in lactose-free dairy milk than those in dairy milk. The principal component analysis (PCA) method was used to discriminate four milk samples depending on their mineral elements concentration. In addition, proteins and fat level in dairy milks were determined using molecular emissions such as CN band. We applied partial least squares regression (PLSR) and simple linear regression (SLR) models to predict levels of milk fat in dairy milk samples. The PLSR model was successfully used to predict levels of milk fat in dairy milk sample with the relative accuracy (RA%) less than 6.62% using CN (0,0) band.

A pharmaceutical study of doxorubicin-loaded PEGylated nanoparticles for magnetic drug targeting.

One of the new strategies to improve cancer chemotherapy is based on new drug delivery systems, like the polyethylene glycol-coated superparamagnetic iron oxide nanoparticles (PEG-SPION, thereafter called PS). In this study, PS are loaded with doxorubicin (DOX) anticancer drug, using a pre-formed DOX-Fe(2+) complex reversible at lower pH of tumour tissues and cancer cells. The DOX loaded PS (DLPS, 3% w/w DOX/iron oxide) present a hydrodynamic size around 60nm and a zeta potential near zero at physiological pH, both parameters being favourable for increased colloidal stability in biological media and decreased elimination by the immune system. At physiological pH of 7.4, 60% of the loaded drug is gradually released from the DLPS in ∼2h. The intracellular release and distribution of DOX is followed by means of confocal spectral imaging (CSI) of the drug fluorescence. The in vitro cytotoxicity of the DLPS on MCF-7 breast cancer cells is equivalent to that of a DOX solution. The reversible association of DOX to the SPION surface and the role of polymer coating on the drug loading/release are discussed, both being critical for the design of novel stealth magnetic nanovectors for chemotherapy.

Novel method of doxorubicin-SPION reversible association for magnetic drug targeting.

A new method of reversible association of doxorubicin (DOX) to superparamagnetic iron oxide nanoparticles (SPION) is developed for magnetically targeted chemotherapy. The efficacy of this approach is evaluated in terms of drug loading, delivery kinetics and cytotoxicity in vitro. Aqueous suspensions of SPION (ferrofluids) were prepared by coprecipitation of ferric and ferrous chlorides in alkaline medium followed by surface oxidation by ferric nitrate and surface treatment with citrate ions. The ferrofluids were loaded with DOX using a pre-formed DOX-Fe(2+) complex. The resulting drug loading was as high as 14% (w/w). This value exceeds the maximal loading known from literature up today. The release of DOX from the nanoparticles is strongly pH-dependent: at pH 7.4 the amount of drug released attains a plateau of approximately 85% after 1h, whereas at pH 4.0 the release is almost immediate. At both pH, the released drug is iron-free. The in vitro cytotoxicity of the DOX-loaded SPION on the MCF-7 breast cancer cell line is similar to that of DOX in solution or even higher, at low-drug concentrations. The present study demonstrates the potential of the novel method of pH-sensitive DOX-SPION association to design novel magnetic nanovectors for chemotherapy.

The development of stable aqueous suspensions of PEGylated SPIONs for biomedical applications.

We report here the development of stable aqueous suspensions of biocompatible superparamagnetic iron oxide nanoparticles (SPIONs). These so-called ferrofluids are useful in a large spectrum of modern biomedical applications, including novel diagnostic tools and targeted therapeutics. In order to provide prolonged circulation times for the nanoparticles in vivo, the initial iron oxide nanoparticles were coated with a biocompatible polymer poly(ethylene glycol) (PEG). To permit covalent bonding of PEG to the SPION surface, the latter was functionalized with a coupling agent, 3-aminopropyltrimethoxysilane (APS). This novel method of SPION PEGylation has been reproduced in numerous independent preparations. At each preparation step, particular attention was paid to determine the physico-chemical characteristics of the samples using a number of analytical techniques such as atomic absorption, Fourier transform infrared (FT-IR) spectroscopy and Raman spectroscopy, transmission electron microscopy (TEM), photon correlation spectroscopy (PCS, used for hydrodynamic diameter and zeta potential measurements) and magnetization measurements. The results confirm that aqueous suspensions of PEGylated SPIONs are stabilized by steric hindrance over a wide pH range between pH 4 and 10. Furthermore, the fact that the nanoparticle surface is nearly neutral is in agreement with immunological stealthiness expected for the future biomedical applications in vivo.