Tag Archives: Antibody

Micromotors Deliver Oral Vaccines

Researchers are working on new generations of oral vaccines for infectious diseases. But to be effective, oral vaccines must survive digestion and reach immune cells within the intestinal wall. As a step in this direction, UC San Diego nanoengineering researchers have developed oral vaccines powered by micromotors that target the mucus layer of the intestine.

The work appears in the ACS journal Nano Letters. It’s a collaboration between the labs of nanoengineering professors Joseph Wang and Liangfang Zhang at the UC San Diego Jacobs School of Engineering.

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The lack of needles is one reason oral vaccines are attractive. Another reason: oral vaccines can generate a broad immune response by stimulating immune cells within the mucus layer of the intestine to produce a special class of antibody called immunoglobulin A (IgA). The NanoLetters paper documents the team’s efforts to use magnesium particles as tiny motors to deliver an oral vaccine against the bacterial pathogen Staphylococcus aureus. When coated over most of their surfaces with titanium dioxide, magnesium microparticles use water as fuel to generate hydrogen bubbles that power their propulsion.

To develop the oral vaccine, the researchers coated magnesium micromotors with red blood cell membranes that displayed the Staphylococcal α-toxin, along with a layer of chitosan to help them stick to the intestinal mucus. Then, they added an enteric coating that protects drugs from the acidic conditions of the stomach.

The micromotors safely passed through the stomach to the intestine, at which point the enteric coating dissolved, activating the motors. Imaging of mice that had been given the vaccine showed that the micromotors accumulated in the intestinal wall much better than non-motorized particles. The micromotors also stimulated the production of about ten times more IgA antibodies against the Staphylococcal α-toxin than the static particles.

Source: http://jacobsschool.ucsd.edu/

Antibodies Are The New Cancer Weapon

Antibody-based imaging* of a particularly aggressive form of breast cancer is undergoing clinical trials worldwide, but the path from trial to application is being hampered by a major obstacle: safety. Concerns stem from inefficient tumor targeting, which can result in accumulation in the bone marrow, liver and kidneys of the radioactive material necessary for the imaging. Recent efforts have focused on nanoscale delivery vehicles with immune components, but these vehicles are often still too large (20 nanometers or larger) for renal clearance after imaging.

Ulrich Wiesner, the Spencer T. Olin Professor of Engineering in materials science and engineering, in collaboration with Dr. Michelle Bradbury of Memorial Sloan Kettering Cancer Center (MSKCC) and Weill Cornell Medicine, has proposed a novel approach using ultrasmall silica nanoparticles – better known as “Cornell dots” (or C dots) – invented in his lab more than a dozen years ago. Their team – including researchers at pharmaceutical company MedImmune – have equipped the C dots with antibody fragments. Because the resulting conjugates are smaller than 8 nanometers, these C dots allow for renal clearance while achieving the specificity needed for efficient tumor targeting.

They report their discovery in in Nature Communications. Feng Chen, senior research scientist at MSKCC, and Kai Ma, postdoctoral researcher in the Wiesner lab, are co-lead authors. Wiesner said this research creates “a whole new runway” to employ antibody fragments for a number of diseases, cancer in particular, and for diagnostics as well as drug delivery – when combined in a single entity also known as “theranostics.”

A rendering of the Cornell prime dot (left) with an attached antibody fragment (center) binding to a HER2 cancer cell receptor (right). The dot and antibody attachment combined are less than 8 nanometers in diameter, the limit for renal clearance.

This is the first time we’ve worked with these antibody fragments,” Wiesner said, “thereby harnessing the power of antibodies in the fight against cancer.”

Cancer imaging is an umbrella term that covers the many approaches used to research and diagnose cancer. Originally used to diagnose and stage the disease, cancer imaging is now also used to assist with surgery and radiotherapy, to look for early responses to cancer therapies and to identify patients who are not responding to treatment.

Source: http://news.cornell.edu/