Are there any restrictions on UMB faculty for becoming PI on a R-21 if the faculty is visa holders and not a US citizens or green card holder?
For the parent R21, a Non-domestic (non-U.S.) components of U.S. Organizations are eligible to apply. For purposes of this policy, a “foreign component” is defined as performance of any significant element or segment of the project outside the United States (U.S.) either by the grantee or by a researcher employed by a foreign institution, whether or not grant funds are expended.
Check each Program Announcement under the Eligibility section to determine if that specific Program Announcement has a restriction on eligibility.
More information on who is eligible for NIH Grants, please see the following website, https://grants.nih.gov/grants/who-is-eligible.htm.