Quantum dot loaded immunomicelles for tumor imaging

<p>Abstract</p> <p>Background</p> <p>Optical imaging is a promising method for the detection of tumors in animals, with speed and minimal invasiveness. We have previously developed a lipid coated quantum dot system that doubles the fluorescence of PEG-grafted quantum dots at half the dose. Here, we describe a tumor-targeted near infrared imaging agent composed of cancer-specific monoclonal anti-nucleosome antibody 2C5, coupled to quantum dot (QD)-containing polymeric micelles, prepared from a polyethylene glycol/phosphatidylethanolamine (PEG-PE) conjugate. Its production is simple and involves no special equipment. Its imaging potential is great since the fluorescence intensity in the tumor is twofold that of non-targeted QD-loaded PEG-PE micelles at one hour after injection.</p> <p>Methods</p> <p>Para-nitrophenol-containing (5%) PEG-PE quantum dot micelles were produced by the thin layer method. Following hydration, 2C5 antibody was attached to the PEG-PE micelles and the QD-micelles were purified using dialysis. 4T1 breast tumors were inoculated subcutaneously in the flank of the animals. A lung pseudometastatic B16F10 melanoma model was developed using tail vein injection. The contrast agents were injected via the tail vein and mice were depilated, anesthetized and imaged on a Kodak Image Station. Images were taken at one, two, and four hours and analyzed using a methodology that produces normalized signal-to-noise data. This allowed for the comparison between different subjects and time points. For the pseudometastatic model, lungs were removed and imaged <it>ex vivo </it>at one and twenty four hours.</p> <p>Results</p> <p>The contrast agent signal intensity at the tumor was double that of the passively targeted QD-micelles with equally fast and sharply contrasted images. With the side views of the animals only tumor is visible, while in the dorsal view internal organs including liver and kidney are visible. <it>Ex vivo </it>results demonstrated that the agent detects melanoma nodes in a lung pseudometastatic model after a 24 hours wash-out period, while at one hour, only a uniform signal is detected.</p> <p>Conclusions</p> <p>The targeted agent produces ultrabright tumor images and double the fluorescence intensity, as rapidly and at the same low dose as the passively targeted agents. It represents a development that may potentially serve to enhance early detection for metastases.</p

Highly sensitive biomarker biosensor for early detection of cancer biomarkers

Abstract Biomarkers are emerging as potentially important diagnostic tools for cancer and many other diseases. However, many current detection systems for suffer from insufficient sensitivity. To address this concern, we developed a highly sensitive biosensor, featuring monoclonal antibody-coated polystyrene nanobeads assembled in the trenches of a microchip, for the detection of cancer biomarkers. These biosensors detected nucleosomes and carcinoembryonic antigen in serum at concentrations of 62.5 and 15.6 pg/mL, respectively. Very low detection limits that suggest such devices might be beneficial for the early detection of tumors and for monitoring of patients in remission.</jats:p

Size-Selective Template-Assisted Electrophoretic Assembly of Nanoparticles for Biosensing Applications

The precise, size-selective assembly of nanoparticles gives rise to many applications where the assembly of nano building blocks with different biological or chemical functionalizations is necessary. We introduce a simple, fast, reproducible-directed assembly technique that enables a complete sorting of nanoparticles with single-particle resolution. Nanoparticles are size-selectively assembled into prefabricated via arrays using a sequential template-directed electrophoretic assembly method. Polystyrene latex (PSL) nanoparticles with diameters ranging from 200 to 50 nm are selectively assembled into vias comparable to nanoparticle diameter. We investigate the effects of particle size and via size on the sorting efficiency. We show that complete sorting can be achieved when the size of the vias is close to the diameter of the nanoparticles and the size distribution of the chosen nanoparticles does not overlap. The results also show that it is necessary to keep the electric field on during the insertion and removal of the template. To elucidate the versatility and nil effects that the electrophoresis assembly technique has on the assembled nanoparticle characteristics, we have assembled cancer-specific monoclonal antibody-2C5-coated nanoparticles and have also shown that they can successfully measure low concentrations of the nucleosome (NS) antigen