Thursday, February 28, 2013

Use of Hydrogel in Cartilage Repair

This article discusses the use of hydrogel in repairing cartilage damage.

Healing Knees with Light-Activated Gel

Damage to cartilage, which lacks its own blood supply, is commonly treated by drilling holes into the surrounding bone and tissue (called microfracturing) in order to stimulate bleeding which helps stem cells to recolonize the damaged area.  The problems with this technique are that the repair tissue often does not completely fill the damaged area and that scar tissue can form instead of cartilage.  Jennifer Elisseef, a biomedical engineer, and her team from Johns Hopkins University tested a different approach to cartilage repair using a light-activated form of hydrogel, a gelatinous substance that is composed of crisscrossing polymer fibers that soak up water.

In their study, Elisseef and her team performed the standard microfracturing technique, but then poured liquid hydrogel into the torn cartilage and then shined a UV light on the gel, causing it to harden (consistency similar to real cartilage).  The hydrogel, which takes the shape of any hole and hardens, provides a physical scaffold for stem cell attachment and also includes chemical and biological factors (such as chondroitin sulfate and hylaronic acid) which inhibit scar tissue formation.  The results showed that 86% of the cartilage was repaired in patients who received the hydrogel treatment.  This is substantially greater than the 64% repair in the control patients who received the standard treatment.  Although the hydrogel shows promising results, further trials will be needed before it can be concluded that the hydrogel is a better long term option than the standard microfracturing technique.

I found this article interesting because cartilage damage is something that occurs during many athletic injuries (as well as others) and can greatly increase the recovery time as well as decrease the amount of recovery that can occur.  The hydrogel technique is brilliant because it provides a scaffold which not only allows an organized surface for stem cells to base cartilage formation from, but also inhibits scar tissue growth.  I can see this technique possibly revolutionizing the way cartilage repair is done.

Estimation of human trunk movements by wearable strain sensors and improvement of sensor’s placement on intelligent biomedical clothes

This study analyses a wearable sensor to record strain caused by trunk movement designed as a shirt. The rehabilitation of the trunk is key to improve balance and allow patient self-sufficiency.The device focuses on recording the macro-movements generally used during rehabilitation instead of micro contractions of the muscles. This leads to instant feedback to the patient and also records data for a physical therapist. This follows the growing trend of user feedback and rehabilitation and patient monitoring. The current device records the information to a device put in a pocket, which could eventually be a smartphone that could upload the data straight to the clinic for a physical therapist to monitor and analyse. This could lead to significantly less patient visits to a physical therapist because they can monitor improvement constantly, as well as instant feedback to a patient to see if any daily activities are creating excess strain.


http://www.biomedical-engineering-online.com/content/11/1/95

A View on Antibiotics and Ear Infections

http://www.npr.org/blogs/health/2013/02/25/172588359/pediatricians-urged-to-treat-ear-infections-more-cautiously

This article is an interesting one that has a few reasons for pertaining to me. It is a synopsis of how to handle children with ear infections. Being written for both parents and doctors, he stresses both that parents should be less tense on throwing their children to the doctor and asking for antibiotics at the first mention of ear pain. Also, he stresses that doctors should prescribe antibiotics only for severe cases of definite ear infections.

The reason being found that nowadays, typical ear infections can resolve in a few days with pain medicine, and would prevent microbial resistance to antibiotics. I find this article interesting in that I had quite a few ear infections when young, and my mom was always very worried about me having taken so many antibiotics. Even to this day she forewarns me about keeping an eye out for the good bacteria in my colon, as she's worried that the antibiotic use when I was young has shot my GI tract. It is ironic that I currently have contracted an ear infection - but a viral one. The doctor I visited here in Germany told me that 95% of the time, ear infections are viral - I assume he's referring to adults with ear infections, so I wasn't given any antibiotics.

Also this brings me to German and European views on healthcare. In short, they are much more stingy with their antibiotics than in the US. This article refers to parents as wanting the antibiotics not just wanting to cure their kids infection, but to also give their child comfort. It also cynically states that no parent enjoys being woken up at night to a screaming child.
I wonder if the German doctor told me the truth about 95% of ear infections are viral... or maybe he was just trying to prevent a greedy American from getting hands on their antibiotics to cause a raging resistant infection. Probably not, but an interesting idea none the less. I've heard of many doctors and health professionals in Europe that do not condone the large use of antibiotics that is seen in the US. But now, with some pain medicine and rest, my ear seems to have returned to normal, crisis avoided.

Valve-Based Printing of Human Organs


A specialized 3D printing process, using human stem cells, could potentially be used to replacement organs for patients, eliminating the need for organ donation, immune system suppression, and possible transplant rejection. The new valve-based technique, developed by the biomedical microengineering group at Heriot-Watt University, Edinburgh, Scotland, a leading stem cell technology company, allowed the researchers to print embryonic cell cultures, which can replicate indefinitely and differentiate into multiple types of cells in the human body. The technique relies on an adjustable "microvalve" to build up layers of human embryonic stem cells (hESCs). Altering the nozzle diameter precisely controls the rate at which cells are dispensed. They say that the technique will allow them to create more accurate human tissue models that are essential to in vitro drug development and toxicity testing. In the long term, they foresee the technology being further developed to create viable 3D organs for medical implantation from a patient’s own cells.

Wednesday, February 27, 2013

Esophageal Sphincter Device for Gastroesophageal Reflux Disease



Gastro-oesophageal reflux disease (GERD), more commonly known as acid reflux, is a disease caused, in most cases, by relaxation of the sphincter.  Proton pump inhibitors are often used to stop secretions of hydrochloric acid by the parietal cells of the stomach. In some patients PPI's are not effective and patients will only see partial symptom relief.  This is due to the fact PPI's only target the acid secretions and not the underlying problem of the ineffective sphincter.  A magnetic device was created to improve barrier function of between the esophagus and stomach by modulating the resistance of the sphincter.




Studies showed the ligature placed around the lower esophageal sphincter prevented the upflow of gastric acid.  The magnetic device functions to provide extra resistance to the sphincter while continuing to allow the passing of food and accommodating for vomiting.  Needless to say as a BMEN major I found this article engaging, because it is in fact a fine product of biomedical engineering.


http://www.nejm.org/doi/full/10.1056/NEJMoa1205544

LIFE Bronchoscopy

In 1996 LIFE Bronchoscopy was approved by the FDA as a diagnostic tool for patients with lung cancer.  Recently it has been brought up to GMP standards and is being regulary used at the UCLA campus.  This tool has become very useful in detecting early stage lung cancers in the airway.  Unlike normal bronchoscopy which is performed under white light, the LIFE bronchoscopy uses fluorescence from the imaging system to detect abnormal cells.  The cancerous tissue will appear darker than the normal tissue and is easier to detect than with a normal bronchoscopy.  Blue light illuminates the tissues and excites fluorophors naturally present in the cancerous tissue.  The article I chose isn't necessarily a new design or thought regarding detection but it interested me because this is what I was doing in lab with Dr. Akabani last semester.  Although I wasn't performing bronchoschopies on patients with potential lung cancer, I was learning how to use a flow cytometer and a small fluorescence machine.  We started using the fluorescence machine on the sample brain cancer cells.  We dyed their nucleuses and other organells in the cell to analyze what they looked like on the machine.  Unfortuantely ( but still fortunately ) I came to Germany when we started to use the machine more in the lab.  I'm looking forward to maybe returning in the fall and knowing that the same technology used in th small machine we used to look at a nucleus is also being used to detect early onsets of lung cancer.

Printing 3D Implantable Ears

Bioengineers at Cornell have figured out a way to 3D print an implantable human ear.  Each year 1 to 4 of 10,000 babies are born with a condition called microtia.  In this condition the infant's outer ear (or ears) is undeveloped.  In many cases the child's inner ear is intact but hearing is lost because of the lack of the external structure.  Currently, replacement ears are made from a sampling of the patient's rib cartilage, but these ears don't look or feel natural and perform poorly.  This new replacement ear could be used to fix the hearing of both children born with microtia as well as trauma and cancer patients who may have lost the external structure of their ear.

Starting with a digitalized 3D image of an ear, Lawrence Bonassar, associate professor of biomedical engineering at Cornell University, used a 3D printer to build a 3D plastic mold of the ear.  The mold was then injected with collagen and living cartilage cells and left to culture for several days before it was ready for implantation.

Cow cartilage is currently being used, but Bonassar and his colleagues are in the process of trying to find a way to use human cartilage instead, potentially even from the same patient to decrease the likelihood of rejection.  Researchers have tested whether the materials used for the mold would become living, useful collagen by implanting a small piece of the mold into rats. After 3 months the "cells took over the collagen, making for a solid-yet-flexible chunk of cartilage that retained its precise shape and size."  This device is not ready for human implantation but could be in as little as 3 to 5 years as soon as a suitable source of collagen can be found.

Links Here and Here

Monday, February 25, 2013

NanoVelcro Device for Analyzing Tumor Cells

Link here.

UCLA has recently developed a "NanoVelcro" chip that collects cancer cells as blood passes through it. It works because it is made up of nanoscale wires or fibers that are coated with protein antibodies that match proteins on the surface of cancer cells. This is where it gets its velcro name from, because the cancer cells latch onto the fibers and are trapped, acting as a liquid biopsy. UCLA can then analyze the gathered cancer cells to provide earlier information about metastases and which specific cancer type it is.

The UCLA research team has also improved the design by replacing the silicon nanowire substrate with a new polymer nanofiber-deposited substrate. These new nanowires help the device to catch the cancer cells more effectively. They have also been able to pick out a single circulating tumor cell with the use of a minaturized laser beam knife. This will help the team create in-depth characterization of the circulating tumor cells to help doctors make better decisions about which treatment to give the patient.

Using this device on circulating melanoma cells can help doctors make sure that the spreading cancer is staying genetically similar to the original tumor they came from. The device will also lead us towards understanding the genes behind cancer cells which allow them to grow at the extreme rate that they do. The NanoVelcro will help us to better personalize drug treatment of cancer and to help understand drug resistances that the cancer has developed.

Friday, February 22, 2013

Fibronectin coating of oxygenator membranes enhances endothelial cell attachment

There has been recent testing on lining the materials used for oxygenation gas exchange membranes with different proteins in an effort to promote the attachment tan proliferation of arterial endotherlial cells. In this artical they mention that if you coat the material with fibronectin there is an increase in the number of endothelial cells that attach to it. In their experiment they tested for a period of four days and saw these results which is plenty long enough to look into using for our device design project for this semester. Also, the  only materiel that had a positive test for confluent cell attachment was polydimethylsiloxane.

Tuesday, February 12, 2013

Increased speed of measuring muscle thickness

As of recently, an ultrasonography was used to measure muscle thickness, which allowed for research into muscle properties and functions. Ultrasonography, however, is time consuming when using the manual method, which was being used up until the investigation into Gabor Filtering and Multiscale Vessel Enhancement Filtering (MVEF). These techniques use a Revoting House Transform to exponentially enhance speed while measuring the muscles. The manual method was used as a control while the two novel methods were used to measure the gastrocnemius muscle. The results showed high comparability to the manual technique. These new methods will now be able to be used for measuring muscles and their functions as a high rate and decrease time wasted as a result of measuring using the manual method.

URL: http://www.biomedical-engineering-online.com/content/12/1/6/abstract