Live 3-D printing of osteogenic scaffolds into bone defects

March 21, 2018, International & American Associations for Dental Research

At the 47th Annual Meeting of the American Association for Dental Research (AADR), held in conjunction with the 42nd Annual Meeting of the Canadian Association for Dental Research (CADR), Venu G. Varanasi (University of Texas at Arlington College of Nursing and Health Innovation and Texas A&M University College of Dentistry, Dallas), presented an oral session titled "Live 3D Printing of Osteogenic Scaffolds Into Bone Defects." The AADR/CADR Annual Meeting is in Fort Lauderdale, Fla., USA from March 21-24, 2018.

Severe traumatic injuries to the cranium have been challenging to heal due to the large missing bone volume. Typically, metal or plastic implants are used. But, these implants can take a long time to be customized for fit and often take a longer than desired time to support bone fixation. This can often lead to multiple revision surgeries if the is not properly healed. Moreover, the tissue that adjoins the implant can improperly heal. For the effective treatment of these defects and injuries, it is necessary to reduce the time and improve the accuracy of implantable bone scaffold substitutes. Further, the microarchitecture and materials chemistry of the scaffold must enhance tissue regeneration and growth to hasten the healing process.

"Our goal is to heal the defect or fracture site rapidly, as if nothing ever happened", said Dr. Varanasi. "We want to develop these methods and materials so that someday we can treat certain types of bone defects like they are dental fillings. Principally, these become out-patient procedures where the patient goes home to heal with the support of their loved ones and with reduced medical expenses owed to extended hospital stays."

The efficacy of bone scaffold substitutes is limited by the rate of bone formation, scaffold-defect mismatch and scaffold displacement during implantation. However, additive in-situ 3D printing can overcome these limitations by printing scaffolds that conform to the dimensions of the defect site.

"In our laboratory," said Dr. Varanasi "we tested several nanobiosilica-based 3D scaffolds with adequate 3D printing properties to potentially improve implantability and rapid bone healing capability. We hypothesized that these scaffolds formed the intended porosity and chemistry for bone and vascular healing. " His lab used a human periosteum cell culture model and a rat cranial defect animal model to illustrate the efficacy of this scaffold and live 3D printing method for potential clinical translation.

The biosilica-biopolymer scaffold was prepared by mixing Laponite (Lp) with methacrylated gelatin (MAG). Sucrose was used to increase viscosity and reduce gelation of the printing ink. IRGACURE 2529 was used as a crosslinking agent. During printing, crosslinking was initiated by UV light at the tip of the printer nozzle and scaffolds were in-situ 3D printed directly into calvaria bone defects using varied Laponite concentration to determine optimal bone density and chemical structure.

Scaffolds were fabricated into a mesh design with dimensions matching that of formed defects and after four weeks, cranial bone samples were extracted. Evaluation by micro-CT showed that nearly 55% of the bone defect was healed after four weeks for higher Lp- rich-MAG scaffolds versus lower Lp-containing MAG scaffolds. Empty control defects only had 11% of the defect filled with bone after four weeks. Histological staining showed that the scaffolds recruited cells into their structure to regenerate the intra-bony layers needed to initiate the healing process.

The results showed that 3D in-situ printing of bone regenerating scaffolds did improve the delivery of regenerative and reconstructive biomedical devices for the proper and rapid healing of fractures. The method allows for the absorption of blood and growth factors into the scaffold as it is being constructed within the defect. This provides an advantage in that cells from within the initial hematoma become incorporated into the scaffold structure, thus, giving the operator flexibility to use the printed as a structural support that stimulates healing," said Dr. Varanasi.

Dr. Varanasi credits the progress made on this work by the research team including mentees Taha Azimaie, Azhar Ilyas, Tugba Cebe, Neelam Ahuja, Ritesh Bhattacharjee, and Felipe Monte as well as close collaboration with Drs Philip Kramer and Likith Reddy (Texas A&M University) and Drs. Marco Brotto and Pranesh Aswath (University of Texas at Arlington). Jim Havelka has served as a senior business mentor. "This project would not have made the strides it made without their efforts. I was just fortunate to have these team members to help develop this work", Dr. Varanasi said.

Dr. Varanasi will now pursue this pioneering work further as part of the Bone-Muscle Group at the University of Texas at Arlington College of Nursing and Health Innovation, and, in collaboration with the University of Texas at Arlington College of Engineering, Texas A&M University College of Engineering, and College of Dentistry. Dr. Varanasi is now underway to identify commercialization and scientific development to help bring this emerging technology to serve patients in the clinic.

Explore further: How metal scaffolds enhance the bone healing process

Related Stories

How metal scaffolds enhance the bone healing process

January 22, 2018
A new study shows how mechanically optimized constructs known as titanium-mesh scaffolds can optimize bone regeneration. The induction of bone regeneration is of importance when treating large bone defects. As demonstrated ...

New study compares bone-inducing properties of 3-D-printed mineralized scaffolds

February 13, 2017
A new study of bone formation from stem cells seeded on 3D-printed bioactive scaffolds combined with different mineral additives showed that some of the scaffold mineral composites induced bone-forming activity better than ...

3-D-printed bioabsorbable scaffold for ACL reconstruction with bone regeneration

February 27, 2017
Researchers have designed a 3D-printed porous scaffold for use in reconstructing ruptured anterior cruciate ligaments (ACL) in the knee and engineered it to deliver a human bone-promoting protein over an extended period of ...

Nanofibres developed for healing bone fractures

January 18, 2017
In the future, it may be possible to use nanofibres to improve the attachment of bone implants, or the fibres may be used directly to scaffold bone regeneration. This would aid the healing of fractures and may enable the ...

Researchers reveal how an inflammatory response to ceramic scaffolds promotes bone regeneration

July 29, 2016
In their mission to design new biomaterials that promote tissue regeneration, Drexel University researchers have identified how inflammation, when precisely controlled, is crucial to bone repair.

Recommended for you

The starch risk to teeth

August 7, 2018
An examination of research on oral health, commissioned by the World Health Organisation, has indicated that for oral health we should stick to whole grain carbohydrates and avoid processed ones, especially if sweet.

Experts question benefits of fluoride-free toothpaste

August 7, 2018
Dental health experts worry that more people are using toothpaste that skips the most important ingredient—fluoride—and leaves them at a greater risk of cavities.

Researchers discover cellular messengers communicate with bacteria in the mouth

May 8, 2018
A new UCLA-led study provides clear evidence that cellular messengers in saliva may be able to regulate the growth of oral bacteria responsible for diseases, such as periodontitis and meningitis.

Drug-filled, 3-D printed dentures could fight off infections

April 25, 2018
Nearly two-thirds of the U.S. denture-wearing population suffer frequent fungal infections that cause inflammation, redness and swelling in the mouth.

Bacteria boost antifungal drug resistance in severe childhood tooth decay

April 25, 2018
Early childhood caries, a form of severe tooth decay affecting toddlers and preschoolers, can set children up for a lifetime of dental and health problems. The problem can be significant enough that surgery is the only effective ...

Absence of a transcription factor halts tooth development in mid-stride

April 11, 2018
Amjad Javed, Ph.D., and University of Alabama at Birmingham colleagues have found a key role in tooth development for the transcription factor Specificity protein 7, or Sp7.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.