Biomedical Engineering Research and Applications

6th world Congress on Biomechanics

2009-12-01T13:55:00.003+01:00

ANNOUNCEMENT
I have just recieved this e-mail:

Come join the 6th World Congress on Biomechanics 2010 in Singapore!

Since 1990, the World Congress on Biomechanics has been held once every four years. The venue revolves around North America, Europe and Asia. The 6th World Congress on Biomechanics (WCB) 2010 will be held in Singapore from 1 to 6 August 2010 at the Suntec Convention Centre. Check out the website: www.wcb2010.net

Call for Abstracts

Please submit your abstracts here:
http://www.wcb2010.net/index.php?option=com_content&view=article&id=2:abstracts-submission&catid=3:abstracts&Itemid=114

Deadline for submission of abstracts; 01 March 2010

Summer School on Biomechanics July 2010

2009-11-20T17:40:00.006+01:00

This summer school on "Modelling in Biomechanics and Mechanobiology at Different Length Scales" is organised by Prof. Holzapfel in Graz, Austria, in the period July 5-9, 2010.

This course is addressed to PhD students but may also be accessible to some undergraduate students with relevant background.

More details of the Summer School can be found at the website:
www.biomech.tugraz.at/summerschool-2010

PhD Studentship at the University of Southampton, UK

2009-10-13T17:36:00.001+02:00

There is a PhD position available on Development of a Mechanistic Wear Model for Analysing the Performance of Total Knee

Replacemen at the University of Southampton, UK. You can find more information on the position here.

If you wish to discuss any details of the project informally, please contact Dr. Georges Limbert, Bioengineering Sciences

Research Group & National Centre for Advanced Tribology (nCATS), SES, University of Southampton, Tel:

+44-(0)23-8059-2381. Email: g.limbert@soton.ac.uk

Magnetic Resonnance Force Microscopy

2009-01-14T14:54:00.004+01:00

I was reading a press release from IBM about a technique called Magnetic Resonnance Force Microscopy(MRFM). Through this technique, one could acheive magnetic resonance imaging (MRI) with a volume resolution 100 million times finer than conventional MRI which is really impressive. Moreover, the technique could be extremely usefull for 3D imaging of small viruses or proteins. The image shows the set up of the apparatus.

The magnetic resonance force microscope (MRFM) is a novel scanned probe instrument which combines the three-dimensional imaging capabilities of magnetic resonance imaging with the high sensitivity and resolution of atomic force microscopy. It will enable non-destructive, chemical-specific, high-resolution microscopic studies and imaging of subsurface properties of a broad range of materials. This technology holds clear potential for atomic-scale resolution.( reference)

Here is a recent journal article published in ' proceedings of the national academy of sciences' where you can find more detailed and scientific explanations about the technique:
Degen et al., ''nanoscale magnetic resonance imaging'', the article is in the presse( published already online),

There is a video on youtube that explains simply how the system works:
http://uk.youtube.com/watch?v=AAA4FGKCBik

2009 Bioengineering conference(SBC2009)

2008-11-11T09:24:00.002+01:00

2009 Summer Bioengineering Conference

Resort at Squaw Creek, Lake Tahoe, CA

June 17-21, 2009

This is a very interesting conference organised by ASME, I have participated in the one in 2007 and I appreciated a lot the organisation and scientific program.

New Inhaled Tuberculosis Vaccination Developed

2008-04-01T10:00:00.004+02:00

Here you can find an article written by Ms. Susan Jacob* as a guest blogger.

University of North Carolina (UNC) and Harvard scientists have recently teamed up to develop an inhaled tuberculosis vaccine. This vaccine is a godsend for developing countries, as it won't require refrigeration and medical-grade water like the typical vaccine.

Professor Tony Hickey, who teaches at the School of Pharmacy at UNC, tells The Kansas City Star, “This is arguably the first step towards future potential vaccines that elicit greater immunity to tuberculosis." Indeed, third-world countries are still being ravaged by the respiratory illness, which reportedly kills millions of people a year in developing areas.

This new inhalant was created by taking the regular tuberculosis vaccine and changing it into fine powder. Experts from both UNC and Harvard collaborated on this project in the laboratory of David Edwards. Edwards is a professor of biomedical engineering at Harvard. The development of the new vaccine was made possible by a grant from the Bill and Melinda Gates Foundation.

Though the inhalant has yet to be tested on human subjects, guinea pigs have responded well thus far. Scientists have administered the drug to the animals, then exposed them to tuberculosis. Not only did the vaccine work well, it appeared to be even more effective than the regular vaccine injections.

The new vaccine will be administered with a plastic tube, which is reportedly similar to a drinking straw. The inhalant is taken orally, which can pose problems with young children. To combat this issue, a special pacifier may be designed for babies to that the inhalant will be blown into the back of their mouths.

The next step to getting the drug on the market is to begin human clinical trials. Hopefully, the vaccination could be used in South Africa as soon as 2009.

*Susan Jacobs is a teacher, a freelance writer as well as a regular contributor for NOEDb, a site helping students obtain an online nursing degree. Susan invites your questions, comments and freelancing job inquiries at her email address susan.jacobs45@gmail.com .

Bioengineering symposium announcement

2008-03-05T15:01:00.002+01:00

Bioengineering 08 ,Imperial College, London, Thursday 18 September-Friday 19 September

If you are interested to attend to this symposium or get more information, click here.

Bravo® Catheter–free pH Monitoring System

2008-02-29T16:01:00.003+01:00

Use of wireless systems in medical devices brings in most of cases more comfort and less damage to the patient. As an example one can name the Bravo pH monitoring system of Medtronics.

The catheter-free Bravo pH Monitoring System is a pH testing with a capsule that collects pH data and transmits it via radio frequency telemetry to a small external pager-sized receiver worn by the patient.

The ambulatory pH test has long been referred to as the "gold standard" for diagnosing reflux disease. This test provides information about the duration, pattern and symptom correlation of distal esophageal acid exposure from gastro-esophageal reflux(GER).

compared to conventional methods associated with using catheter pH systems, this method:

Allows patients to maintain regular diet and activities
Minimizes throat and nasal discomfort
Allows physicians to extend pH data collection to 48 hours — 24 hours beyond the recording capability of conventional catheter systems

more information: click here

A New Fluorescent collagen probe to use on fresh tissue

2008-02-19T15:42:00.007+01:00

Collagen is one the important load-bearing components in the body and the collagen structure has a distinct role in mechanical properties of the tissue. One of the challenges today is to visualize the collagen structure in live tissues or fresh tissues without fixing the tissue. It's clear that fixing methods are invasive and may alter the tissue structure. As an example, in tissue engineering experiments, visualization of changes in collagen three dimensional structure is essential for the understanding of collagen fibrils formation and remodeling.

Fluorescent CNA35 collagen probe developed in the laboratory of macromolecular and organic chemistry, Eindhoven University of Technology, The Netherlands, shows much specificity to collagen compared to other existing fluorescent techniques currently used for collagen visualization in live tissues and shows improved details compared to SHG ( second harmonic generation microscopy). However, in my opinion, the tissue should be relatively thin to let the prob perfuse all over the tissue.

The figure shows a mouse carotid artery, (Up) SHG signal of collagen (green), (down) fluorescence signal of collagen probe (green, CNA35-OG488) in a mouse carotid artery recorded at the same focal position obtained with two-photon laser scanning microscopy (15 μm deep)

reference:
High resolution imaging of collagen organisation and synthesis using a versatile collagen specific probe, Journal of Structural Biology
Volume 159, Issue 3, September 2007, Pages 392-399

FP7 Collaborations in the Manufacturing Sector,17-18 th Jan 2008

2007-12-14T13:19:00.000+01:00

International Partnering Meeting & Successful R&D Project Preparation for the Second Call for Proposals in the Nanotechnology, Materials and New Production Technologies Programme

Initiate your collaborative project or become a partner in an EU-project
The general aim of the international partnering meeting is to facilitate transnational R&D-collaboration between industry, Small and Medium Sized Enterprises (SMEs) and research organisations active in the field of manufacturing and in particular to setup Framework Programme 7 (FP7) projects.

Targeted Audience: European and Swiss representatives from manufacturing industry and related academia; etc.

Deadline to send 5 min presentations: 11 Jan 2008

more detailed information: click here!

Virtual Colonoscopy Procedure for Easier Colon Screening

2007-12-10T14:04:00.000+01:00

Numerous patients who need a screening of the colon do not go through the procedure for fear of the procedure. The colonoscopy procedure that is currently available involves inserting a flexible tube with a viewing instrument into the rectum. It requires anaesthesia and there's a remote chance that the colon wall could be perforated by the tube. However, patients now have an easier option with the discovery of a procedure called 'Virtual Colonoscopy'. This procedure, allows computerized scanning of the colon which is more comfortable for the patient. The patient is made to lie down in a computerized tomography (CT) scanner while a small probe is inserted into the rectum so that the colon can be inflated with carbon dioxide gas. The CT scanner then takes 3 dimensional images of the whole colon, which can then be examined for polyps. The patient does not need anaesthesia and the procedure takes only half an hour. However, the procedure is purely diagnostic and if doctors find a polyp, the regular colonoscopy procedure has to be done for removal and assessment of the polyp. Further, cleansing of bowel is still required that most of patients find unpleasant.

reference: Bio-Medecine

upcoming event: the 2007 annual conference of the EPFL chapter of BMES, LAUSANNE,Switzerland

2007-10-18T10:12:00.000+02:00

The meeting would be interested for those working in the field of Bioengineering in Switzerland. The conference is organised by the BMES* chapter at EPFL( Swiss federal institute of Technology,Lausanne)

Bioengineering in Academics and Industry:

Meet the two Worlds
31^st October 2007 (9h00 to 14h00)
Deadline for title submission for posters: 20th October

In order to register, simply send your poster title to bmes@epfl.ch before 20^th of October. You don’t need to send any abstracts.

Please note that two cash prizes will be given to the selected posters by our jury.

Program of the meeting is available at http://bmes.epfl.c

For more information please contact bmes@epfl.ch

*: BMES Biomedical Engineering Society

Robotic Therapy Tiles: Playing Your Way to Health

2007-10-12T11:19:00.000+02:00

Patients recovering from surgery or injuries may soon be able to physically play their way to a full recovery with intelligent robotic systems that generate specialized games to challenge the human body's abilities.

abilities Henrik Hautop Lund, a robotics and artificial-intelligence professor at the University of Southern Denmark is developing therapy tiles that guide patients through physical routines and help them heal.

Each tile is a miniature robotic system employing neural networks. The system looks like an elaborate, electronic version of Twister. As patients step on or press the tiles with their hands, the tiles give feedback, indicating whether ther pressure is firm enough, or if the user is moving quickly enough. Individuals can use the game alone, or up to four patients can compete against each other in a game. The tiles can be assembled in any configuration on the walls and floor to create an intelligent game space.

reference

Drugless approach that could thin blood during open-heart surgeries

2007-10-08T09:01:00.000+02:00

Brigham Young University researchers recently developed a new anticoagulation strategy for use during extracorporeal circulation (ECC) that does not involve systemic administration of heparin, which causes negative reactions in three to 10 percent of surgical patients. "Rather than give something to the patient to prevent coagulation, let's take something out," says BYU biomedical engineer Kenneth A. Solen, who led the study published in the August issue of ASAIO Journal (the journal of the American Society for Artificial Internal Organs).

Solen’s team inhibited coagulation by absorbing plasma clotting factors using protamine immobilized on a Sepharose matrix (PSM). In a porcine ex-vivo circuit, plasma was separated from blood via plasmapheresis, passed through a column containing PSM beads, and then returned. After 90 minutes, prothrombin time (PT) was prolonged more than 10 times the baseline and blood clotting Factors I (fibrinogen), II (prothrombin), VIII, and X were decreased more than 90 percent. This state was maintained for 2 ½ hours without any detectable adverse consequences. Within 60 minutes of ECC cessation, PT approached normal levels and hemostasis was restored.

For More readings: Take a look at here.

Source:

Blake Ferguson
University Communications
Brigham Young University

The Venture business plan competetion 2008 Switzerland

2007-10-05T16:28:00.000+02:00

"Venture 2008 takes you from business idea to professional business plan and all the way to the financing and founding of a company. The Venture business plan competition takes place every two years and combines a competition, learning events and contact forum in one."

Venture 2008 is an initiative of the ETH Zurich and McKinsey & Company, Switzerland. The Swiss-wide business plan competition supports young entrepreneurs in founding a company.

Experienced coaches support competition participants in the preparation of their business plans and in the search for suitable partners and the necessary capital. Participants also receive feedback from the team of highly qualified jurors. The jurors (approximately 80 people) belong to one of two groups: entrepreneurs, who evaluate the formal and business aspects of an idea, and venture capitalists, who evaluate its financial attractiveness. Jury members also act as coaches. Venture 2008 offers total prize money of CHF 150,000 for the winning business ideas and business plans.

For details of the competion click here.

Entrepreneurial opportunity identification: bring the gap between Research and its applications!

2007-09-28T17:26:00.000+02:00

Lately, I have been participating in a course given by Prof. Gruber at the college of management of technology at EPFL on entrepreneurial opportunity identification and exploitation.

Here, I would like to make a brief resume of what I found interesting during recent discussions that we had in the program. This is about the very early stage of entrepreneurship when one might search or discover, through a mere idea or a technology, feasible market applications. I hope, this would be helpful for those researchers who seek to found a start-up or simply apply their knowledge in the “real world”.

1. Discovery of market opportunities depends on the information that people already possess. In a simpler world, different people might see different applications in a single technology or idea partly because of their different background. What you may see as a researcher as a potential application of the technology, may not be the only possible opportunity. It seems that it might be beneficial to make a heterogonous team to have some other feedbacks.

2. Identification and analysis of different opportunities in the market would help, later, in the productivity of the founded companies. This suggests that maybe looking at one or two alternative markets before entering to one might increase the chance to succeed. One should find a compromise between the effort, time and money that should be spent on this identification and the added value that it could bring to the market.

References:

Scott Shane, ‘prior knowledge and the discovery of the entrepreneurial opportunities’, Organization Science, 2000, vol. 11, No. 4, pp 448-469

Class notes of the mentioned course.

Upcoming conference 2008

2007-09-21T13:41:00.000+02:00

16th congress of European society of Biomechanics,

Lucerne, Switzerland

July 6th-9th 2008

Deadline for abstract sumbission: 30th November 2007

First announcement and call for abstracts

Computed Ultrasound Risk Evaluation (C.U.R.E.)

2007-09-18T17:42:00.000+02:00

During the last annual meeting of SSBE in Neuchatel, Switzerland, there was an interesting talk about a project called CURE, an undergoing study at the Karmanos Cancer institute,Detroit(USA). The talk was given by Prof. Neb Duric.

Here is a summary of Cure project:

C.U.R.E.: Computed Ultrasound Risk Evaluation

The project is an attempt to image breast, based on the interaction of acoustic waves with human tissue.

It is known that the relative risk of developing breast cancer is dependent on breast density. However, since x-ray mammography has poor sensitivity in dense breasts, the reliance on mammography to measure density has prevented expanded adoption of breast density as a risk factor. The ultrasound tomography provides a safe and alternative measure for assessing beast cancer risk and for identifying high risk groups.

Ultrasound tomography does not use ionizing radiation and does not compress the breast. For those who have already been subject to mamography, it is clear that squeasing the breast to bring it to an almost 2D state, is really painful. This approach would provide a potentially more specific alternative to mammography.

For more information about the project, take a look at this reference, where one should find even a nice powerpoint file.There are more information available on results of the project as well.

Conference announcement 2007

2007-09-10T10:22:00.000+02:00

“Innovation in Drug Delivery: From Biomaterials to Devices”
30 September – 3 October 2007

http://www.apgi.org/missive/missive.htm

Symposium on Cardiovascular Diseases, Fribourg, Switzerland october 18,19 th ,2007

2007-09-04T11:41:00.000+02:00

Here, you can find the announcement and registration form for the following symposium:

Cardiovascular Diseases -

The Blood, the Vasculature, and the Perivasculature

(October 18 and 19^th, 2007, Fribourg, Switzerland)

Organizers: Zhihong Yang and Brenda R.

Registration is free but mandatory.

Current event: Annual meeting of Biomechanics Society, France

2007-08-28T17:22:00.000+02:00

XXXIIème congrès annuel de la société de Biomécanique,
Lyon,France 28-29 août 2007

XXXIIth annual meeting of French biomechanical societyLyon,France 28-29 August 2007

Medical Devices Vigilance regulations in Switzerland

2007-08-24T10:42:00.000+02:00

Swissmedic is the central Swiss supervisory authority for therapeutic products. It is a public service organization of the federal government with headquarters in Bern.

Its core competence includes

licensing medicines
granting authorizations to manufacture and distribute wholesale, and inspecting facilities
monitoring medicines and medical devices already on the market
controlling the traffic of narcotics
laboratory testing of medicine quality
drafting laws and standards

Medical devices Vigilance:

In order to monitor medical devices already on the market, manufacturers and distributors placing medical devices on the Swiss market are required to report all serious incidents and recalls that are carried out for safety reasons.

The European guidelines on vigilance to report procedure applies also in Switzerland. MEDDEV 2.12/1.
Incidents: people responsible for the product on the market, should report incidences to Swissmed. An information sheet from Swissmedic describes the legal obligations and the reporting procedure for serious incidents.
Recalls: In case of recall of a product from market, Swissmedic should be informed.

To get more information about Vigilance procedure in Switzerland, take a look at the following link:

Vigilance: reporting serious incidents with medical devices

A little survey

2007-08-22T14:55:00.001+02:00

In order to adapt better my posts to those who frequent my blog, I would appreciate if you answer the following question:

MENIETT , a device from medtronic

2007-08-17T21:18:00.000+02:00

Ménière's Disease is a complex, progressive disorder of the inner ear characterized by the feeling of dizziness or a "spinning" sensation (rotational vertigo) associated with hearing loss, fullness or pressure in the ear, and roaring or ringing in the ear (tinnitus).

The cause of Ménière's Disease is nearly always idiopathic, meaning it is unknown. Research suggests that the primary problem is in the endolymphatic sac, an organ in the inner ear, which maintains the level of fluid (endolymph) in the hearing and balance canals of the inner ear. It is possible, but unproven, that a viral infection of the sac may trigger the onset of Ménière's Disease.

It has been discovered that the endolymphatic sac contains a substance that stimulates the kidneys to get rid of water and sodium. Although the nature of this substance and how it is regulated are still unknown, it is tempting to speculate that the endolymphatic sac is involved in the body's system to regulate sodium concentration. If this were true, it would explain why a low-sodium diet helps some people with Ménière's Disease.

The Meniett device is a product of MEDTRONIC to alleviate Ménière's Disease symptoms.

The inner ear consists of the cochlea (hearing canal), endolymphatic sac, semicircular canals (balance canals), and the hearing and balance nerves.This image shows endolymphatic fluid circulating in the cochlea (1) and semicircular canals (2), as well as the endolymphatic sac (3), where the endolymph is accumulated.

In Ménière's Disease, excess endolymphatic fluid accumulates in the hearing and balance canals, causing pressure to build and the canals to swell. The swollen canals cannot function properly, which leads to problems with the hearing and balance systems of the ear.

Treatment begins after the Meniett device performs a leakage test to verify that the earpiece is properly sealed in the external ear canal . Once the leakage test is completed successfully, the device will begin sending pressure pulses that are transmitted to the middle ear through the ventilation tube.

Pressure pulses help reduce excess endolymphatic fluid and restore the balance of the inner ear's hydrodynamic system.

The ventilation tube allows the pressure pulses to reach the middle ear, where they influence the fluid system of the inner ear through two membranes, the oval window and the round window.

Although the actual mechanisms are still not fully understood, one theory is that the action of the pressure pulses on the fluid system, combined with other physiologic reactions in the ear, forces the excess endolymphatic fluid back into the endolymphatic sac.

Once the treatment is completedthe volume of endolymphatic fluid in the inner ear has been reduced. However, the body constantly produces endolymphatic fluid, thus requiring the patient to perform the Meniett treatment on a daily basis to control the symptoms of Ménière's Disease.

for more information take a look at : reference

Studies of the outer-most layer of the vascular wall, adventita as a seperate layer

2007-08-10T16:47:00.001+02:00

A small Introduction on different vascular layers:

The walls of all blood vessels, except the very smallest, have three distinct layers, or tunics( 'covering') , that surround a central blood-containing space, the vessel lumen. The innermost tunic is the tunica intima which is in direct contact with the blood in the lumen. This tunic contains the endothelium. The middle tuinic, the tunica media is mostly contained of smooth muscle cells, elastin and collagen fibers. The outermost layer of a blood vessel wall, the tunica externa(adventitia) is composed of loosely woven collagen fibers that protect and reinforce the vessel and anchor it to surrounding structure.

Main post:

As for the biomechanical properties of the vascular tissue, there has been quite a large number of studies done. Some of these studies report inflation-extension types of experiments done on scaffold of adventitia removed from a whole vessel. Others, have just removed out the adventitia and focused on media. The question is :

Is it really possible for all type of vessels to take out adventitia out of the vessel mechanically?

To my knowledge, this seems quite a local and specie dependent property. It looks that in some arteries , such as human femoral arteries, you can easily separate the adventitia from the rest of the vessel. However, according my experiments, it is almost impossible to take it as a whole intact cylinder out from common carotid, femoral, abdominal arteries and Jagular,facial,femoral,abdominal veins of rabbits. As for common carotid of rats, I may say, it may be possible though I had never really done it.

let's consider that you have done it. Since it is a kind of bulky collagen fibers, it does not seem really impermeable to liquids. Thus, inflating of this layer, even if we can get it from the artery, seems quite a hard job.

Have you ever tried working with adventitia layer separately in inflation-extension tests? I would appreciate as you inform me on the subject.

picture taken from : reference

Single Molecule manipulations 3

2007-08-06T17:03:00.000+02:00

As part of their infection cycle, many viruses must package their newly replicated genomes inside a protein capsid to insure its proper transport and delivery to other host cells. Bacteriophage 29 packages its 6.6mm long double-stranded DNA into a 42 nm dia. X 54 nm high capsid via a portal complex that hydrolyses ATP. This process is remarkable because entropic, electrostatic, and bending energies of the DNA must be overcome to package the DNA to near-crystalline density.

In a recent work by Dr Bustamante, optical tweezers have been used to pull on single DNA molecules as they are packaged, thus demonstrating that the portal complex is a force generating motor. They have shown that this motor can work against loads of up to ~57 picoNewtons on average, making it one of the strongest molecular motors ever reported. Interestingly, the packaging rate decreases as the prohead is filled, indicating that an internal
pressure builds up due to DNA compression. It is estimated that at the end of the packaging the capsid pressure is ~6 MegaPascals, corresponding to an internal force of ~50 pN acting on the motor.

Reference

Mathematical modeling of biomechanical properties of the venous wall

2007-08-02T14:22:00.000+02:00

Despite the abundant literature on blood vessel mechanical properties, blood vessel constitutive models are far less common. Blood vessels are nonlinear, anisotropic and viscoelastic, heterogeneous in the unloaded state and compressible when studying macroscopic characteristic and they behave differently in different temperatures. Despite the long list of attributes, constitutive equations generally account for only a subset of these characteristics.

In general, blood vessels can be treated as pseudoelastic, randomly elastic, poroelastic or viscoelastic . Pseudoelasticity assumes that a material can be modeled using separate equations describing the loading and unloading behavior. Random elasticity, however, assumes that the strain response for a given load is rendered around a definite value that lies on a well defined curve, such that data from both the loading and unloading curves can be included simultaneously. Poroelastic formulations treat a material as a fluid-saturated porous medium and are well suited to model wall transport. Viscoelastic formulations include time-dependent responses in the constitutive equation and are useful for modeling creep, stress relaxation, and hysteresis. Useful reviews are available, concerning the biomechanics of soft biological tissues :

Vito, R.P. and S.A. Dixon, Blood vessel constitutive models-1995-2002. Annual Review Of Biomedical Engineering, 2003. 5: p. 413-439.

Humphrey, J.D., Continuum biomechanics of soft biological tissues. Proceedings: Mathematical, Physical and Engineering Sciences (Series A), 2003. 459(2029): p. 3-46.

Medecins & medical devices Regulations in UK

2007-07-20T15:14:00.000+02:00

Here, you can find a quite useful article in pdf format from the MHRA website about :

What is the MHRA?
How does licensing and authorisation work?
How does the MHRA monitor the safety and quality standards?
Influencing policy

Detection of collagen fibers using Second harmonic generation (SHG) imaging

2007-07-17T17:01:00.000+02:00

One remarkable ability of multiphoton microscopy is to provide images with micrometer 3 -dimensional (3D) resolution from within intact biological tissues. An emerging application is the observation of unstained live tissue, based on endogenous sources of nonlinear signals. Imaging intrinsic signals with molecular or structural specificity can be achieved by combining twophoton-excited fluorescence (2PEF) microscopy, second harmonic generation (SHG) microscopy, and spectrally selective detection. Endogenous sources of signal for tissue 2PEF imaging are the same as those excited by conventional one-photon absorption with near-UV or blue excitation: NAD(P)H, flavoproteins, elastin fibers, etc.However, two-photon excitation provides superior imaging depth compared with confocal/conventional microscopy[1].

In a recent study, we tried to image arterial collagen found in the media using SHG. However, it seems that there is a technical problem. Most of collagen found in the media layer of arterial wall is consisted of type IV collagen which is not detectable with SHG.however, the fibrillar collagen in adventitia (mostly type I and III) is detectable. (looking at the figure shown from ref. 1 ,in green is the collagen in adventitia and in red one find the elastin laminas in media of the vessel wall.) Here is my question: Has anyone of you ever tried to image the collagen in media in an unstained tissue using SHG?

[1] T. Boulesteix et al. , " Micrometer scale Ex Vivo multiphoton imaging of unstained arterial wall structure" Cytometry Part A, 69A(1), pp. 20-26.

more suggested readings:

High resolution imaging of collagen organisation and synthesis using a versatile collagen specific probe

Upcoming conferences ,September 2007

2007-07-12T15:17:00.000+02:00

Online registrations open:

BMES annual fall meeting 2007 , Los Angeles, 26-29 September

Registration Open, Deadline:Auguste 29, 2007

Swiss Society of Biomedical Engineering(SSBE) 2007 Meeting: CSEM Neuchâtel ,13-14 September 2007

Registration Open, deadline: Auguste 14, 2007

Single Molecule Manipulations in Biophysics 2

2007-07-11T11:45:00.000+02:00

Torque Measurements on single DNA Molecules

The physical properties of the DNA double helix are unlike those of any other natural or synthetic polymer. The molecule’s characteristic base stacking and braided architecture lend it unusual stiffness: It takes about 50 times more energy to bend a double-stranded DNA molecule into a circle than to perform the same operation on single-stranded DNA. Moreover, the phosphates in DNA’s backbone make it one of the most highly charged polymers known.

To perform dynamic torque measurements on single DNA molecules, molecular constructs were made.This kind of experiments have been performed in the Prof. Bustamante's laboratory at Berkeley University.

The use of three distinct chemical modifications of DNA allows for oriented tethering of the ends of the molecule and the subsequent attachment of a rotor to a third, internal position (shown on the figure). A site-specific nick in the duplex DNA is engineered adjacent to the rotor attachment point; this design allows covalent bonds in the intact strand to serve as free swivels, preventing torque from accumulating in the "lower" DNA segment. Thus, torque stored in the "upper" segment can drive the rotation of a submicron object on a low-friction molecular bearing. At low Reynolds numbers, the magnitude of the torque can be measured by multiplying the observed angular velocity by the rotational drag of the rotor.

To be continued

reference: Bustamante, C.Of torques, forces, and protein machines(2004) Protein Science, 13 (11), pp. 3061-3065.doi: 10.1110/ps.041064504

What is Biomedical Engineering?

2007-07-09T11:14:00.000+02:00

Biomedical engineering integrates physical, chemical, mathematical, and computational sciences and engineering principles to study biology, medicine, behavior, and health.

It advances fundamental concepts; creates knowledge from the molecular to the organ systems level; and develops innovative biologics, materials, processes, implants, devices and informatics approaches for the prevention, diagnosis, and treatment of disease, for patient rehabilitation, and for improving health.

NIH working definition of bioengineering – July 24, 1997

Single Molecules Manipulations in Biophysics

2007-07-06T11:11:00.000+02:00

Until very recently, chemists and biochemists have had to rely on bulk methods to investigate the properties of molecules and their reactions. These methods did not make it possible to directly investigate the nature, strength, and direction of intermolecular forces and torques.

During the last few years, however, the advent of novel methods of single-molecule manipulation have begun to offer researchers, for the first time, the opportunity to measure directly the forces holding molecular structures together, to measure the stresses and strains generated in the course of chemical and biochemical reactions, to exert external forces to alter the fate of these reactions, and to reveal the rules that govern the interconversion of mechanical and chemical energy in these reactions. This area of research can be rightly called mechanochemistry.

Biochemical processes as diverse as protein folding, DNA elasticity, the protein-induced bending of DNA, the stress-induced catalysis of enzymes, the mechanical properties of protein motors, and even the ubiquitous process of induced-fit molecular recognition of proteins for their ligands, are all examples in which stresses and strains develop in molecules as they move along a reaction coordinate.

to be continued

reference: Bustamante, C.Of torques, forces, and protein machines(2004) Protein Science, 13 (11), pp. 3061-3065.doi: 10.1110/ps.041064504

Upcoming conferences 2008

2007-06-29T10:41:00.003+02:00

ASME Summer Bioengineering conference , Marco Island, Florida
June 25-29, 2008

http://divisions.asme.org/bed/events/sbc2008.html

deadline to submit abstracts: January 31, 2008

Engineering world Health Organisation

2007-06-27T15:17:00.001+02:00

Engineering world health organisation http://www.ewh.org/ is a not-for-profit charitable organisation which trys to use the capacities of engineering schools and engineers to promote the global health specifically by identifying the needs of hospitals in developing world and by helping them to overcome some of the existing difficulties that they have.

This organisation is involved in the aid for assessment of needs of hospitals in developing world, helping in delivery and maintainance of the devices needed as well as training people in hopitals to use and repair the medical devices.

The organisation, encourages design of new medical devices and equipements suitable for these countries ( since their needs is different from developped countries) and build existing designs to ship in these countries.

The Summer Institute is an opportunity for engineering students to gain hands on repair and design experience while simultaneously helping disadvantaged hospitals and patients in a developing nation. Open to students of engineering, physics and chemistry, the Summer starts from one month of intensive technical training combined by courses on language and culture of disadvantage countries and then sent to help hospitals in the areas most needed. To get more information, take a look at their website: http://www.ewh.org/summer/index.php

Complex Biomedical devices 2

2007-06-27T15:04:00.000+02:00

As sue has mentioned in the comments of the previous post, at the first glance, cool.click™may seem a combination product, however it has to be categorized in one group to get through the legislations.

Normally, a device that is just used to DELIVER a drug ( as a syringe) is considered as a pharmaceutical product and should get through pharmaceutical legislations. However, sometimes this is the company who decides what is a main function of the product and how it wants to introduce its product and then gets through negotiations with legislative organisations to reach to an agreement about the nature of the product.

Does the device do something more than the drug delivery? Do mechanical parts or electronical parts have physical roles in the treatment,etc? These questions arise while deciding the category of the product. an example may be a coated stent.

In conclusion , It should be considered that the answer to these questions are not always very clear. Sometimes a product may be accepted as a medical device in Europe while as a pharmaceutical product in US and vice versa. The descision is made after discussions between companies and EMEA in Europe or FDA in the US.

Complex biomedical devices

2007-06-18T14:45:00.000+02:00

cool.click
cool.click™ is a needle-free device that delivers Saizen® through the skin The drug is delivered subcutaneously and provides the equivalent biological dose of Saizen® as do needle injections. Because it is needle-free, cool.click™ reduces pain and anxiety for patients that are undergoing daily treatment for Growth Hormone Deficiency. Looking at this product, in which group would you place it: is it a medical device or pharmaceutical product?

Modeling of Arterial Cerebral Circulation

2007-06-04T14:59:00.000+02:00

Studies of Cerebral aneurysm properties provide a better evaluation of their rupture’s danger, which may be deadly. As these properties change with time, ruptures are difficult to assess. CFD analysis is an efficient tool to provide information on the temporal variation of the mechanical forces acting on the aneurysm wall.

Intracranial arteries flow rate and pressure waveforms have to be provided as a boundary condition for CFD simulation in the vicinity of cerebral aneurysm. As the waveform changes from an artery to another, there’s a need to model main cerebral arteries to get the corresponding waveform. This model should go through a validation process to guatantee the result’s accuracy.

To improve and validate the model, reference results are needed: in vivo measurements to provide flow rate and pressure waveforms for cerebral modelled arteries. Measurements can be collected with MRI (general cerebral vasculature’s geometry), Doppler ultrasound (flow rate waveform) and Tonometry (pressure waveform) ,etc. The age range of study group is important. Young people’s artery properties is different from aged ones.

by: Virginie Chenaux

Upcoming conferences ( 3)

2007-05-30T10:57:00.000+02:00

Swiss Society of Biomedical Enginnering (SSBE) annual meeting 2007 . (CSEM Neuchatel,Switzerland) ,september 13th and 14th. Deadline for abstracts: June 12th.

more information : http://www.ssbe.ch/2007_Meeting/

Complex biomedical devices; combining Pharma & medical technology

2007-05-25T10:11:00.000+02:00

In the past, there used to be a quite distinct cut between medical devices and pharmaceutical products and intersection of devices and drugs occurred only at use. Examples of these kinds of medical devices are PCA pumps and imaging agents.

However, nowadays Drugs are added to devices to add value to medical devices and improve their function and efficiency. Moreover, sophisticated drug delivery systems integrate drugs and devices. We can mention transformal patches, coated catheters and drug eluting stents as some examples.

It is not really clearer if a combination of device-drug should be classified as a medical device or a pharmaceutical product. This becomes extremely important when it comes to regulatory affaires. Currently regulatory systems for pharmaceutical products and biomedical devices are totally different and not always really easy to handle for companies. Mostly this classification is claimed by the company and challenged by authorities. However, that may not end to a same classification in all the regions of the world. These kinds of Complex devices may be accepted in one region as a pharmaceutical product and in the other one as a biomedical device requiring two completely different procedure in the view of clinical trial and regulatory procedures. The problem may be much more important when it comes to devices combined with stem cells, tissue engineered materials and so on.

Deep Brain Stimulation

2007-05-17T22:15:00.000+02:00

Deep Brain Stimulation (DBS), is currently used to treat the symptoms of Parkinson's Disease, essential tremor, dystonia, and other complex movement disorders and affective syndromes.
This process requires using different mechanical devices as well as image processing methods and micro drive mechanisms. Medtronics is one of the companies offering a solution for this intervention process. Take a look at their device Activa:
http://www.medtronic.com/physician/activa/

Physiome Project

2007-05-14T16:19:00.000+02:00

Have you already heard of the Physiome Project? This is an idea to '' provide a computational framework for understanding human and other eukaryotic physiology. It aims to develop integrative models at all levels of biological organisation, from genes to the whole organism via gene regulatory networks, protein pathways, integrative cell function, and tissue and whole organ structure/function relations. ''

Although their website may not seem very interesting at the first look, you can find a lot of useful information in the ''Roadmap'' or through the review articles that you can find on the homepage. Take a look at it! The idea is great and they have some useful tools and databases to use as well. ENJOY!

Animal experiments, ethics and regulations

2007-04-04T17:20:00.000+02:00

As a Biomedical Engineer, one may be involved up to certain levels in some animal experiments .This involvement can alter based on the nature of project. some may only work with data already obtained from in vivo or in vitro tests while others may have be in direct contact with animals.

I won't go through the question of if we have the right to perform animal experiments and to which extent. Here, I will consider readers, already in some degree of contact with animals and animal experiments.

In Switzerland, the animal experiments are allowed but under strict laws and regulation : Formative courses are done and regulations are checked continuously; research project which develop and use alternative methods to animal experiments are encouraged;principle of RRR (Reduction, Replacement and Refinement) are getting more and more recognized and so on.

However, I believe that finally, it is every single scientist that should be aware of ethics in this issue. This is not a simple subjects and there are several debates on it. I would suggest to keep your sensibility on the subject and Respect some ethical issues and while respecting animals.

for further information , check out:

Towards responsible animal research
Animal experiments in EC Legislation
UK legislation
Swiss Regulations
Animal welfare act and regulations in US

Complex Biomedical Devices and Immunoresponse of the body

2007-04-02T11:24:00.000+02:00

One of the basic requirements of materials used in medical devices is their biocompatibiliy. They should not raise severe immunoresponses that can be hazardous for the patient or may alter the functionality of the device.

Biomedical devices are becoming more and more complex containing different combinations of drugs, biological and instrumental components. Recent studies shows while the effect of each combination may be known, the presence of them together, may lead to some unexpected complications.

Looking for more simple explanations?

Take a look at the following link of The Georgia Institute of Technology ,

http://www.gatech.edu/news-room/release.php?id=526

Soft tissue mechanics

2007-03-29T17:48:00.000+02:00

Soft tissues are inhomogeneous, anisotropic materials which show viscoelastic and nonlinear properties. Morover, even under physiological conditions they undergo large deformations. For instance, in arteries, the in vivo longitudinal stretch ratio may pass more than 1.6. ( in vivo length/ unloaded length=1.6)

These properties make the continuum approach suitable for the purpose of analyzing material properties of soft tissue. Therefore, knowledge of nonlinear solid mechanics by a continuum approach seems essential.

Identification of an appropriate strain energy function (SEF) is the preferred method to describe the complex nonlinear elastic properties of vascular tissues. Once the strain energy function is known, the constitutive stress-strain relationships can be directly obtained from the SEF.

Early formulations of SEFs were purely phenomenological, in the sense that parameters involved in the mathematical expression of SEF bared little physiological meaning. Lately, significant effort has been put into developing structure-based or constituent-based SEF, where the parameters of the strain energy function represent some identifiable physical or structural characteristics of the different components of the vessel wall, such as elastic constants of elastin and collagen, fiber structural characteristics of the collagen network, volume fraction of elastin, collagen and vascular smooth muscle cells, etc.

An example of a constituent -based SEF which considers some structural properties, i.e. the orientation of the collagen fibers relative to the arterial wall’s circumferential direction is the model by Holzapfel and colleagues. The Holzapfel et al. model has been subsequently modified and extended by Zulliger et al. take the waviness of collagen fibers into the account and later to include vascular tone.

The structure-based SEFs did provide a significant improvement over the previous phenomenological SEFs. Furthermore, they supplied scientists more powerful tools to relate morpholoy with mechanical properties of soft tissue. Pa

CISM : international center for mechanical sciences

2007-03-22T17:18:00.000+01:00

CISM, International Centre For Mechanical Sciences, offers different specialized courses in in interdisciplinary fields like robotics, biomechanics, environmental engineering and so on. I participated in the following summer course last year 2006 :

Biomechanical Modelling at the Molecular, Cellular and Tissue Levels

The course was really interesting and the organisation was very well-done. That was a really fantastic opportunity to encounter people working in this field and to discuss with the professors as well as the students and research people. Furthermore, Udine,the city in which the organisation is situated, is a really cute small Italian town close to Venice. If you have a chance to participate in one of the courses offered by CISM, don't hesitate to go.http://cism.it/

P.S. The picture shows the classroom.

Mechanobiology versus Biomechanics

2007-03-16T19:32:00.000+01:00

I heard once these definitions from Prof. J.Humphrey and I find them quite nice :

Mechanobiology – the study of altered cellularactivity (gene expression or function) in response to changes in mechanical stimuli.

Biomechanics – the development, extension,and application of mechanics for purposes of understanding better biology, physiology, and pathophysiology as well as the treatment of disease and injury.(must invoke the 5 basic postulates of mechanics)

what I really like about the latter, is that mechanic laws should be extended and developed in order to be used in living tissue. We can not always use the existing rules. We should look for new ones, new relationships and discover new horizons. For sure, we have to remain in the framework of principle of mechanics.

up coming conferences (2)

2007-03-16T19:23:00.000+01:00

European Symposium of Vascular Biomaterials(ESVB2007)
http://www.esvb.uha.fr/

Upcoming conferences (1)

2007-03-13T16:57:00.000+01:00

summer bioengineering conference, keystone,colorado,USA June 20-24 2007
http://divisions.asme.org/bed/events/summer07.html