Nanoparticles May Soon Regenerate Damaged Joint Cartilage

At 25 years of age, Jerry is a fully grown adult athlete in his prime. He runs marathons regularly, and occasionally engages in rough sports for fun. In a recent bone-jarring accident while playing soccer, Jerry damages the cartilage in one of his hips.

After consulting his physician, Jerry limps away from his doctor's office contemplating one of several options - and none of them really address his problem.

Jerry can:

* Do nothing and hope for the best.

* Have the damaged cartilage removed from his hip and reduce his exercise to nothing beyond "pleasant walks in the countryside" - perhaps for the rest of his life.

* Have his hip replaced altogether with an artificial joint and resume his activities with the likelihood of pain.

Each option Jerry weighs has its respective risks, and none of them really address his problem.

Doing nothing and hoping for the best will likely result in Jerry's causing further damage to his joint. If the pain from the actual injury or the later arthritis that develops as a result of his injury doesn't stop him from walking, the actual loss of function in his hip will. He could lose his job as a warehouse worker, and - in a worst-case scenario - he may eventually be reduced to walking painfully with crutches, or being wheelchair-ridden.

Having the damaged cartilage removed may assist in slowing further damage to Jerry's hip. However, he may experience pain as a result of a later onset of osteoarthritis and - at the least - Jerry could never be as vigorously active again.

While replacement of his joint may overall sound like Jerry's most promising option, this option is extremely invasive, expensive, and Jerry runs the risk of his body being allergic to the man-made materials that comprise his new hip.

The Problem with Cartilage

Innumerable people such as professional and amateur athletes, the elderly, and other people whose joints have simply worn out get bad news when they seek counsel from an orthopedic surgeon about their shoulders, knees, and elbows.

"Unlike bone, cartilage does not grow back, and therefore clinical strategies to regenerate this tissue are of great interest," says Samuel I. Stupp, Director of the Institute for BioNanotechnology in Medicine, Board of Trustees Professor of Chemistry, Materials Science and Engineering, and Medicine.

"Cartilage does not regenerate in adults. Once you are fully grown you have all the cartilage you'll ever have," says first author Ramille N. Shah, a resident faculty member at the Institute for BioNanotechnology in Medicine. Shah is also an assistant professor of orthopedic surgery at the Feinberg School of Medicine, and is an assistant professor of materials science and engineering at the McCormick School of Engineering and Applied Science.

Type II collagen is the major ingredient that comprises articular cartilage, which is a smooth, white connective tissue covering the epiphyses (ends of bones), the place where individual bones come into contact with one another to form a joint.

New Option on the Horizon: Nanoparticles

As a possible up-and-coming option to the risky options listed above, people with damaged cartilage may soon enjoy a chance at beating nature's rules - by growing new cartilage.

How? Nanoparticle technology.

What is a Nanoparticle?

A nanoparticle is generally defined as a small (say, microscopic) object that behaves as a whole unit in terms of its delivery, function, and properties. Nanoparticles are genrally classified according to diameter, which is measured in nanometers (one-billionth of a meter). For reference, a sheet of paper is approximately 100,000 nanometers thick.

Fine nanoparticles' diameters generally range from 100 to 2500 nanometers, while ultrafine particles range between 1 to 100 nanometers wide.

Nanoparticles come in various shapes: some are round, while others may be oblong or ribbon-shaped. Microscopic nanoparticles can work as single units, or can work together in aggregate bunches linked together in a random or an ordered sequence. For example, an ordered sequence nanoparticles made primarily of carbon may serve as a specially designed component that augments the lubricative properties of an automotive engine oil.

While this is one example of how nanoparticles can be employed in industry, they may soon provide new hope for people in the medical realm.

Nanoparticles Purposed for New Cartilage Growth

In the case of damaged cartilage, researchers at Northwestern University are the first to have designed a biologically active nanomaterial that enhances the growth of new cartilage on the site of the damaged tissue - all without the need for expensive materials or difficult procedures. The technique needed to deliver the nanomaterial is minimally invasive. This technology activates bone marrow stem cells and results in the production of natural Type II collagen-based cartilage. For the time being, no other conventional therapy can provide this.

Upon injection into the joint cavity at the area of damage to the joint, the nanomaterial attaches itself to the affected area and automatically assembles itself into a structured solid called a matrix. This matrix mimics a growth factor on the damaged area which in turn stimulates cartilaginous stem cells to reproduce. After approximately one month, the matrix has been replaced by actual cartilage growth, and the original components of the matrix biodegrade into nutrients.

In the Works

While this technique has only been formally used with animals, it is still in the works for approval with human subjects. People with debilitating cartilage damage may soon look forward to this new technology to ease their suffering, and enjoy a more active lifestyle through the renewed use of their joints.

Resources:

http://www.understandingnano.com/nanomedicine-nanofibers-cartilage-growth.html

http://www.orthosupersite.com/view.aspx?rid=23139