This paper demonstrates a proof-of-concept approach for encapsulating the anticancer drug tamoxifen, Fe3O4 nanoparticles (NPs) and CdTe quantum dots (QDs) into size-controlled polycaprolactone (PCL) microcapsules utilizing microfluidic emulsification, which combined magnetic targeting, fluorescence imaging and drug controlled release properties into one drug delivery system. Cross-linking the composite PCL microcapsules with poly(vinyl alcohol) (PVA) tailored their size, morphology, optical and magnetic properties and drug release behaviors. The flow conditions of the two immiscible solutions were adjusted in order to successfully generate various sizes of polymer droplets. The result showed superparamagnetic and fluorescent properties, and was used as a controlled drug release vehicle. The composite magnetic and fluorescent PCL microcapsules are potential candidates for a smart drug delivery system.
Citrate-capped gold nanoparticles (AuNPs) serve as matrices for the determination of biomolecules in a high-salt solution through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In the case of using 2,5-dihydroxybenzoic acid (2,5-DHB) as a matrix, the signal intensities of neutral steroids were severely suppressed in a high-salt solution. A high concentration of NaCl caused the formation of the sodium adduct ions during the desorption/ionization process, resulting in a decrease of the signal intensities of the protonated ions. In comparison, by applying AuNP-assisted LDI-TOF-MS, the signal intensities of neutral steroids remained almost constant when the concentration of NaCl was increased to 500 mM. Because the use of citrate-capped AuNPs as matrices primarily offers alkali metal ion adducts, AuNP matrices have a higher tolerance to high NaCl concentrations relative to that of 2,5-DHB matrices. The relevant phenomena are also discovered in the case of analysis of neutral carbohydrate, monosialoganglioside, indolamine, and angiotensin I. The quantification of small molecules in a high-salt solution has been accomplished by AuNP-assisted LDI-TOF-MS coupled to a unique sample preparation, in which samples are deposited onto the sample plate before AuNPs. The present method has been further applied to the determination of urea, creatinine, uric acid, and glucose in a urine sample. (J Am Soc Mass Spectrom 2009, 20, 875-882)
This report describes a method for enrichment and separation of acidic and basic proteins using the centrifugal ultrafiltration followed by nanoparticle-filled capillary electrophoresis. To improve stacking and separation efficiencies of proteins, the separation buffer containing 1.6% poly(diallyldimethylammonium chloride) was added with gold nanoparticles (AuNP), poly(ethylene oxide), cetyltrimethylammonium bromide, and poly(vinyl alcohol). As a result, the use of AuNP as additives exhibited better efficiency in separation, stacking, and analysis time. Even for large-volume samples (110 nL), the separation efficiencies of acidic and basic proteins remained greater than 10(4) and 10(5) plates/m, respectively. To further enhance detection sensitivity, protein samples were enriched using the centrifugal ultrafiltration, followed by our proposed stacking method. The detection sensitivity was improved up to 314-fold compared to normal hydrodynamic injection. Additionally, the limits of detection at a signal-to-noise of 3 for most proteins were down to nanomolar range. We have validated the application of our method by means of analyses of 50 nM lysozyme in saliva samples. The proposed method was also successfully applied to the analyses of egg-white proteins, which have large differences in molecular weight and pI.
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