Ultra-small fatty acid-stabilized magnetite nanocolloids synthesized by in situ hydrolytic precipitation

© 2015 Kheireddine El-Boubbou et al. Simple, fast, large-scale, and cost-effective preparation of uniform controlled magnetic nanoparticles remains a major hurdle on the way towards magnetically targeted applications at realistic technical conditions. Herein, we present a unique one-pot approach that relies on simple basic hydrolytic in situ coprecipitation of inexpensive metal salts (Fe<sup>2+</sup> and Fe<sup>3+</sup>) compartmentalized by stabilizing fatty acids and aided by the presence of alkylamines. The synthesis was performed at relatively low temperatures (80°C) without the use of high-boiling point solvents and elevated temperatures. This method allowed for the production of ultra-small, colloidal, and hydrophobically stabilized magnetite metal oxide nanoparticles readily dispersed in organic solvents. The results reveal that the obtained magnetite nanoparticles exhibit narrow size distributions, good monodispersities, high saturation magnetizations, and excellent colloidal stabilities. When the [fatty acid]: [Fe] ratio was varied, control over nanoparticle diameters within the range of 2-10 nm was achieved. The amount of fatty acid and alkylamine used during the reaction proved critical in governing morphology, dispersity, uniformity, and colloidal stability. Upon exchange with water-soluble polymers, the ultra-small sized particles become biologically relevant, with great promise for theranostic applications as imaging and magnetically targeted delivery vehicles

Virus-like particle nanoreactors: programmed en capsulation of the thermostable CelB glycosidase inside the P22 capsid

Self-assembling biological systems hold great potential for the synthetic construction of new active soft nanomaterials. Here we demonstrate the hierarchical bottom-up assembly of bacteriophage P22 virus-like particles (VLPs) that encapsulate the thermostable CelB glycosidase creating catalytically active nanoreactors. The in vivo assembly and encapsulation produces P22 VLPs with a high packaging density of the tetrameric CelB, but without loss of enzyme activity or the ability of the P22 VLP to undergo unique morphological transitions that modify the VLPs internal volume and shell porosity. The P22 VLPs encapsulating CelB are also shown to retain a high percentage of the enzyme activity upon being embedded and immobilized in a polymeric matri

Paramagnetické nanočástice jako platforma pro FRET-Based pikomolární detekci sarkosinu

Herein, we describe an ultrasensitive specific biosensing system for detection of sarcosine as a potential biomarker of prostate carcinoma based on Forster resonance energy transfer (FRET). The FRET biosensor employs anti-sarcosine antibodies immobilized on paramagnetic nanoparticles surface for specific antigen binding. Successful binding of sarcosine leads to assembly of a sandwich construct composed of anti-sarcosine antibodies keeping the Forster distance (Ro) of FRET pair in required proximity. The detection is based on spectral overlap between gold-functionalized green fluorescent protein and antibodies@quantum dots bioconjugate (lex 400 nm). The saturation curve of sarcosine based on FRET efficiency (F604/F510 ratio) was tested within linear dynamic range from 5 to 50 nM with detection limit down to 50 pM. Assembled biosensor was then successfully employed for sarcosine quantification in prostatic cell lines (PC3, 22Rv1, PNT1A), and urinary samples of prostate adenocarcinoma patients.V tomto dokumentu, popíšeme ultrasensitivní specifický biosnímací systém pro detekci sarkosinu jako potenciálního biomarker karcinomu prostaty na základě Forster přenosu rezonanční energie (FRET). Pražec biosensoru zaměstnává anti-protilátku sarkosinu, která je imobilizovaná na povrchu paramagnetických nanočástic pro specifickou antigenní vazbu. Úspěšná vazba sarkosinu vede k sestavení sendvičové konstrukce složené z anti-protilátky sarkosinu, udržení Forster vzdálenost (RO) a FRET páru v požadované blízkosti. Detekce je založena na spektrálním překryvu mezi zlatem s funkčním zeleným fluorescenčním proteinem, protilátkou a kvantovými tečkami Bioconjugate (400 nm). Saturace křivky sarkosinu na základě FRET účinnosti (F604 / F510 poměr) byl testován v lineárním dynamickém rozsahu od 5 do 50 nM s detekčním limitem až do 50 pM. Montované biosenzor byl pak úspěšně použity pro sarkosinu kvantifikac