Novel Innovations for Tissue Regeneration in Osteoarthritis

The Big Question

What if we could make our joints heal themselves?

The Problem

How often do most people think about their healthy joints? Probably not much. But when the cartilage and bone that make up our joints starts to deteriorate – usually as the result of age or injury – the effects can be impossible to ignore. People begin to suffer from stiffness, pain, and in some cases even total loss of mobility.

This degenerative disease – known as osteoarthritis – currently affects around 32 million people nationwide, with numbers predicted to rise sharply as the population ages. Osteoarthritis is already the third most common type of disability and has an estimated economic burden of more than $136 billion per year.

The Current State

In the United States today, treating osteoarthritis usually involves open joint surgery – typically replacing cartilage with invasive, lab-grown grafts and bone/joints with titanium alloy implants. These methods can be very successful, but they also come with risks such as infection, graft rejection, implant failure, and the need for revision surgery. Due to the high cost of surgery and a lack of specialty care in some locations, equitable access to osteoarthritis treatment for all can be limited.

The Challenge

Novel Innovations for Tissue Regeneration in Osteoarthritis (NITRO) aims to address current issues surrounding osteoarthritis treatment by developing new ways of helping the human body repair its own joints. In particular, the program focuses on three technical areas: injectable bone regeneratives, injectable cartilage regeneratives, and replacement joints built from human cells.

In the first two instances, the NITRO team plans to leverage recent innovations in a wide variety of disciplines – including regenerative medicine, biomedical engineering, and biomaterials – to create therapeutics that can fully regenerate damaged joints. If successful, these therapeutics will stimulate naturally occurring biological repair mechanisms within the joint itself – and in doing so help the body to heal damaged cartilage and bone without surgical intervention.

If the joint has deteriorated beyond the point of repair, NITRO’s third research area involves developing replacement joints made from a patients’ own cells. These joints won’t require any permanent fixation (plates and screws) and will signal the formation of new bone and cartilage. If successful, they will also be load-bearing and non-immunogenic – meaning that they won’t be rejected by the immune system – ultimately preventing patients from needing repeat surgery.

The Solution

In order to meet these goals, ARPA-H invites those interested in NITRO to read the full BAA. Successful applicants will work with a diverse team of performers to address the biggest challenges facing osteoarthritis patients today. In doing so, NITRO performers may help reduce health costs, increase access, and drastically improve the lives of millions of people with or at risk for osteoarthritis.

Broad Agency Announcement (BAA)


Proposal Due Date: Closed

Proposers’ Day

Proposers’ Day: June 15, 2023, 9:00 AM - 6:00 PM ET (8:00 AM - 5:00 PM CT)

Proposers’ Day Video

NITRO Osteoarthritis Model Symposium

Second NITRO OA Model Symposium: February 22, 2024, 12:00 PM - 4:00 PM EDT (Virtual)

Symposium Registration is closed.

Symposium Special Notice



Frequently Asked Questions



NITRO anticipates that teaming will be necessary to achieve the goals of the program. Prospective performers are encouraged (but not required) to form teams with varied technical expertise to submit a proposal to the NITRO BAA. To facilitate this process, we have created a teaming page where prospective performers can share their profiles and learn more about other interested parties.

Teaming Page