Biological Technologies Office -- Bridging the Gap Plus (BGPlus)

Funding Agency:
Defense Advanced Research Projects Agency

The Bridging the Gap Plus (BG+) program will focus on new approaches to treating spinal cord injury by developing systems that address acute injury stabilization, regenerative therapy, and chronic functional restoration. 

Spinal cord injury is a complex condition that causes partial or complete loss of function below the location of injury. Those who are injured often face lifelong paralysis and increased longterm morbidity due to factors such as sepsis or functional complications. According to the United States (U.S.) Department of Veterans Affairs, tens of thousands of U.S. veterans live with some form of spinal cord injury. The injury profile is often unique to the individual and typically progresses through three major phases, each with different characteristics. The acute phase (typically 0-48 hours) includes hemorrhage and inflammation at the site of injury, often requiring surgery to minimize secondary injury. The sub-acute phase (typically 2-14 days) follows, during which there is an expanded zone of damage as the cells that were not impacted by the initial injury begin to die within the increasingly cytotoxic environment. The chronic phase (beyond 14 days) exhibits vasculature and neural reorganization, stabilization, and limited nerve regrowth in very specific circumstances. 

While considerable research efforts have been devoted toward restorative and therapeutic technologies, significant challenges remain. For example, devices designed for restoring various functions typically do not deliver the appropriate sensory feedback (e.g., proprioception) to the user or the nervous system, thus limiting their effectiveness and usability. With respect to regenerative medicine, efforts have focused on regenerating/repairing nerve projections using electrical stimulation, pharmacology, cell therapy, and scaffolds. These approaches have been difficult to translate into the clinic and do not leverage neuronal feedback mechanisms or biomarker information to track progress and adjust treatment paradigms. 

The Bridging the Gap Plus (BG+) program will develop new approaches to treating spinal cord injury by integrating injury stabilization, regenerative therapy, and functional restoration. To achieve this combinatorial approach, BG+ teams will build two systems of implantable and adaptive devices. The first system will reduce injury effects during the acute and subacute phases of spinal cord injury. This system will consist of active devices that will perform real-time biomarker monitoring and intervention to stabilize – and where possible, rebuild – the neural communications pathways at the site of injury, providing the clinician with previously unavailable diagnostic information for automated or clinician-directed interventions. The second system will primarily address recovery of function in the chronic phase and will involve stimulation and/or recording devices that may be deployed anywhere on the nervous system or relevant end organs to effectively “bridge the gap” of the spinal cord injury.

DARPA is soliciting innovative proposals for the BG+ program that will mitigate the early effects of injury, lead to improved awareness and interactive therapies at the penumbral zone to preserve neural function, and restore multiple functions (e.g., movement/sensation, posture/proprioception, bladder, bowel, respiratory). The final deliverables will adapt to the change in injury profile over time, inform new standards of care for the acute effects of injury, minimize secondary complications, and address the long-term dysfunctions that remain for years after injury.


o Proposal Abstract Due Date: November 25, 2019

o Full Proposal Due Date: January 22, 2020​

Agency Website

Areas of Interest

BG+ includes two Technical Areas (TAs) that will run concurrently throughout the five-year program. The overall program timeline and technical milestones for the program are listed in Section 1.6. 

Proposers must apply to both TAs listed below.

  • Technical Area 1 (TA1). Injury Stabilization and Therapeutic Stimulation
  • Technical Area 2 (TA2). Functional Recovery

Funding Type





Engineering and Physical Sciences
Environmental & Life Sciences
Medical - Basic Science
Medical - Clinical Science
Medical - Translational

External Deadline

January 22, 2020