Microwave-assisted synthesis of biofunctional and fluorescent silicon nanoparticles using proteins as hydrophilic ligands.
ABSTRACT Protective shell: A microwave-assisted method allows rapid production of biofunctional and fluorescent silicon nanoparticles (SiNPs), which can be used for cell labeling. Such SiNPs feature excellent aqueous dispersibility, are strongly fluorescent, storable, photostable, stable at different pH values, and biocompatible. The method opens new avenues for designing multifunctional SiNPs and related silicon nanostructures.
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ABSTRACT: Despite the fact that pathogenic infections are widely treated by antibiotics in the clinic nowadays, the increasing risk of multidrug-resistance associated with abuse of antibiotics is becoming a major concern in global public health. The increased death toll caused by pathogenic bacterial infection calls for effective antibiotic alternatives. Lysozyme-coated mesoporous silica nanoparticles (MSNs⊂Lys) are reported as antibacterial agents that exhibit efficient antibacterial activity both in vitro and in vivo with low cytotoxicity and negligible hemolytic side effect. The Lys corona provides multivalent interaction between MSNs⊂Lys and bacterial walls and consequently raises the local concentration of Lys on the surface of cell walls, which promotes hydrolysis of peptidoglycans and increases membrane-perturbation abilities. The minimal inhibition concentration (MIC) of MSNs⊂Lys is fivefold lower than that of free Lys in vitro. The antibacterial efficacy of MSNs⊂Lys is evaluated in vivo by using an intestine-infected mouse model. Experimental results indicate that the number of bacteria surviving in the colon is three orders of magnitude lower than in the untreated group. These natural antibacterial enzyme-modified nanoparticles open up a new avenue for design and synthesis of next-generation antibacterial agents as alternatives to antibiotics.Advanced healthcare materials. 03/2013; 2(10):1351-1360.
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ABSTRACT: Stem-loop oligonucleotides tagged with organic dyes are employed as capture and reporter probes in a molecular beacon-based signal-off surface- enhanced Raman scattering (SERS) strategy. DNA strands are immobilized on a gold nanoparticle-decorated silicon nanowire array (AuNPs@SiNWAr). DNA with a concentration down to ≈10 fM is detected under irradiation from a low-power laser, which is better than or comparable to that detected by signal-on SERS methods. The signal-off strategy allows identification of single-base mismatches and detection of multiplexed DNA.Small 01/2013; · 7.82 Impact Factor
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ABSTRACT: Near-infrared (NIR, 700-900 nm) fluorescent quantum dots are highly promising as NIR bioprobes for high-resolution and high-sensitivity bioimaging applications. In this article, we present a class of NIR-emitting CdTe/CdS/ZnS core-shell-shell quantum dots (QDs), which are directly prepared in aqueous phase via a facile microwave synthesis. Significantly, the prepared NIR-emitting QDs possess excellent aqueous dispersibility, strong photoluminescence, favorable biocompatibility, robust storage-, chemical-, and photo-stability, and finely tunable emission in the NIR range (700-800 nm). The QDs are readily functionalized with antibodies for use in immunofluorescent bioimaging, yielding highly spectrally and spatially resolved emission for in vitro and in vivo imaging. In comparison to the large size of 15-30 nm of the conventional NIR QDs, the extremely small size (∼4.2 nm or 7.5 nm measured by TEM or DLS, respectively) of our QDs offers great opportunities for high-efficiency and high-sensitivity targeted imaging in cells and animals.Biomaterials 09/2013; · 8.31 Impact Factor