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Center for Advanced Regenerative Engineering

Unlocking our Body's Potential to Heal

Learn More About CARE

What is CARE

Housed within the McCormick School of Engineering and Applied Science, the Center for Advanced Regenerative Engineering (CARE) is a targeted initiative led by Prof. Guillermo Ameer that integrates and supports research, technology development, and clinical expertise to improve the outcome of tissue and organ repair and regeneration for adult and pediatric patients. CARE is a partnership that includes Northwestern University's Feinberg School of Medicine, the University of Chicago's Pritzker School of Medicine, the Shirley Ryan AbilityLab, the Ann and Robert H. Lurie Children’s Hospital of Chicago, the International Institute for Nanotechnology, and various companies interested in the implementation of regenerative medicine.

Gotta Go? New Bladder Device Lets You Know

Implant and app enables patients to monitor bladder function

By Amanda Morris, Engineering News 3/25/24

Should you run to the bathroom now? Or can you hold it until you get home? A new implant and associated smartphone app may someday remove the guess work from the equation.

Northwestern University researchers have developed a new soft, flexible, battery-free implant that attaches to the bladder wall to sense filling. Then, it wirelessly — and simultaneously — transmits data to a smartphone app, so users can monitor their bladder fullness in real time. 

The study will be published this week in the Proceedings of the National Academy of Sciences (PNAS). It marks the first example of a bioelectronic sensor that enables continuous monitoring of bladder function for a prolonged period.

While this new device is unnecessary for the average person, it could be a game-changer for people with paralysis, spina bifida, bladder cancer, or end-stage bladder disease — where bladder function is often compromised, and bladder reconstruction surgery may be required. The sensor system also can enable clinicians to monitor their patients remotely and continuously to make more informed — and faster — treatment decisions.

“If bladder nerves are damaged from surgery or from a disease such as spina bifida, then a patient often loses sensation and is unaware that their bladder is full,” said Northwestern’s Guillermo A. Ameer, who co-led the work. “To empty the bladder, they often have to use catheters, which are uncomfortable and can lead to painful infections. We want to eliminate the use of catheters and bypass current bladder function monitoring procedures, which are highly invasive, very unpleasant, and must be done in a hospital or clinical setting.”

Read the Complete Story

This story was also featured in US News and World Report, and on the National Institute of Health's website.

Acuitive Technologies Receives FDA 510(k) Clearance for CITRELOCK DUO

CITRELOCK DUO is a new sports medicine fixation device for biceps tenodesis and tendon transfer procedures incorporating technology developed at CARE

Acuitive Technologies Press Release, 9/27/23

ALLENDALE, N.J., Sept. 27, 2023 (GLOBE NEWSWIRE) -- Acuitive Technologies, Inc. (Acuitive) today announced the FDA 510(k) Clearance of CITRELOCK DUO Fixation Device for biceps tenodesis. The new fixation device provides surgeons a differentiated design via a tendon-friendly spiral thread featuring a next-generation resorbable technology, known as CITREGEN®, that has unique molecular and mechanical properties for orthopedic surgical applications.

The CITRELOCK DUO offers surgeons:

  • Biomimetic material composition to match the native bone inorganic content
  • A novel soft spiral thread design to avoid tendon laceration
  • A compressive strength similar to cortical bone and a modulus similar to trabecular bone
  • Elastomeric properties for improved pull-out strength
  • A controlled resorption rate to mitigate chronic inflammation

The full press release can be found on Acuitive Techologies' website.

Designing Surfaces to Improve Bone Grafts

New research demonstrates a concept to create more bone

By Brian Sandalow, Engineering News 6/12/23

The field of bone implants has taken incredible strides thanks to technological innovations that allow for stronger grafts that are easier to install.

Yet even with these advances, there are still risks involved in such procedures. Implants can be loosened following operations, for example, which can lead to costly surgical revisions that lengthen the recovery process for patients. 

New research from an interdisciplinary team from Northwestern Engineering’s Center for Advanced Regenerative Engineering (CARE) and Center for Physical Genomics and Engineering (CPGE) could reduce the likelihood of these painful, expensive complications.


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First transient electronic bandage speeds healing by 30%

Bandage also monitors the healing process, alerting clinicians to issues in real time

By Amanda Morris, Northwestern Now 2/22/23

Northwestern University researchers have developed a first-of-its-kind small, flexible, stretchable bandage that accelerates healing by delivering electrotherapy directly to the wound site. 

In an animal study, the new bandage healed diabetic ulcers 30% faster than in mice without the bandage. 

The bandage also actively monitors the healing process and then harmlessly dissolves — electrodes and all — into the body after it is no longer needed. The new device could provide a powerful tool for patients with diabetes, whose ulcers can lead to various complications, including amputated limbs or even death.

The research was published online today (Feb. 22) in the journal Science Advances. It marks the first bioresorbable bandage capable of delivering electrotherapy and the first example of a smart regenerative system. 

“When a person develops a wound, the goal is always to close that wound as quickly as possible,” said Northwestern’s Guillermo A. Ameer, who co-led the study. “Otherwise, an open wound is susceptible to infection. And, for people with diabetes, infections are even harder to treat and more dangerous. For these patients, there is a major unmet need for cost-effective solutions that really work for them. Our new bandage is cost-effective, easy to apply, adaptable, comfortable and efficient at closing wounds to prevent infections and further complications.” 

“Although it’s an electronic device, the active components that interface with the wound bed are entirely resorbable,” said Northwestern’s John A. Rogers, who co-led the study. “As such, the materials disappear naturally after the healing process is complete, thereby avoiding any damage to the tissue that could otherwise be caused by physical extraction.”

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Digitaltrends ES, CBC Radio - Radio Active, House of Wellness, and B1G sports broadcasts featured segments or stories on this device.

Stryker Launches Citrefix Suture Anchor System, Featuring Award-winning Citregen Biomaterial

Stryker recently announced the launch of Citrefix a suture anchor system for foot and ankle surgical procedures. The new system uses a citrate-based biomaterial referred to as Citregen, a bioresorbable material designed to mimic the chemistry and structure of native bone. Citrate-based biomaterials were originally developed by Guillermo Ameer’s team at Northwestern University for tissue engineering and regenerative medicine applications. Ameer was awarded the Society for Biomaterials Technology Innovation and Development Award in 2022 for his work on these materials. Polydiolcitrates are the first biodegradable thermoset polymers used for implantable medical devices cleared by the U.S.A. Food and Drug Administration for use in surgeries.  


Citrefix is a disposable suture anchor system that features a resorbable biomimetic anchor body. Citregen enables controlled resorption without chronic inflammation. Citregen's unique chemical and mechanical properties are designed to help grafted tissue heal and healthy bone grow when used in orthopaedic surgical applications. After the launch of Citrelock in 2021, Citrefix is the second product in Stryker’s portfolio using the material, with additional products expected in 2023.

To view the full press release, please click HERE

Courtesy of the Society for Biomaterials

Biomaterial Developed in CARE Labs to be Widely Available Through a Device by Stryker Corporation

September 24, 2021

Citregen reabsorption. Photo credit: Acuitive Technologies
Citregen reabsorption. Photo credit: Acuitive Technologies


The novel biomaterial Citregen™, developed in the Center for Advanced Regenerative Engineering, is being adopted into a new orthopaedic device being distributed by Stryker.  Stryker is one of the world’s leading medical technology companies, and their Trauma & Extremities division has launched its Citrelock™ Tendon Fixation Device System.  Citregen’s unique chemical and mechanical properties make this system an innovative offering in a number of ways.  For example, it provides a controlled and homogeneous resorption process that prevents bulk degradation and chronic inflammation, and maintains structural integrity during the healing phase, while the implant is replaced by host tissue.

Read Stryker’s press release, find more information about Stryker’s product release here.

The development and commercialization of a novel biomaterial is a rare accomplishment.  Read an article in Northwestern Now by Lila Reynolds that features the development of CITREGEN™ in Dr. Ameer's labs.

Watch Stryker's video to learn more about Citrelock technology:


Medical devices that use biomaterial technology developed at CARE receive FDA clearance

March 4, 2021


Three devices using the core material technology CITREGEN, pioneered by Dr. Guillermo Ameer and his lab, have received U.S. Food and Drug Administration (FDA) approval.  These devices were designed by Acuitive Technologies.

The CITRESPLINE/CITRELOCK™ system (pictured right) is intended to firmly engage tendons and ligaments within a bone tunnel while preserving the integrity of the soft tissue during insertion of the device. These products are intended to be used during orthopedic surgeries for fixation of ligament or tendon tissue repairs of the knee, shoulder, elbow, wrist, hand, ankle, and foot.  Acuitive Technologies, Inc. intends to commercialize the CITRESPLINE and CITRELOCK System with an orthopedic distribution partner to compete in the Sports Medicine market. 

Read the full press release by Acuitive Technologies, Inc. here.

Learn more about CITREGEN™ technology.


February 15, 2021

CITREFIX™ Knotless Suture Anchor System

The CITREFIX™ Knotless Suture Anchor System (pictured right) is intended to assist the attachment of tissue to bone during orthopedic surgeries such as fixation of ligaments or tendon graft tissue repairs of the shoulder, elbow, wrist, hand, knee, ankle, and foot extremities.  Read more about the product and announcement here.


October 2020

CITRELOCK tendon fixation devices. Credit: Acuitive Technologies

The Center for Advanced Regenerative Engineering, led by its director  Guillermo Ameer, has pioneered an innovative orthopedic medical device fabricated from a novel biomaterial, and has received clearance from the U.S. Food and Drug Administration (FDA) for use in surgeries to attach soft tissue grafts to bone.

The biomaterial is the first thermoset biodegradable synthetic polymer ever approved for use in an implantable medical device.  Ameer’s biomaterial, called CITREGEN™, helps grafted tissues heal by recreating their intrinsic biochemical and structural support network.  CITREGEN™ is the core material technology in the CITRELOCK™ Interference Screw System (pictured above).  The system is intended for soft tissue attachment or fixing ligaments and tendon graft tissue in joint surgeries. 

“CITREGEN is an unprecedented and innovative bioresorbable biomaterial technology developed to support the body’s normal healing process and promote tissue regeneration,” Ameer said. “When used to fabricate devices for reconstruction of tissues, such as ligaments, blood vessels, bladder and bone, results have been impressive and beyond our expectations.”

Read the full story about the device as covered by Northwestern News.


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