One assignee leads clearly with 108 of the 364 records in scope, well ahead of the fifth-place holder at 17. The top 5 assignees combined hold 216 records, 59.3% of the field, which means the claim space is concentrated rather than evenly spread across the 99 companies in the ranking. Anyone entering this space should check that leading portfolio first, since it covers a disproportionate share of the core hardware claims.

Filings peaked at 42 in 2023 after rising from 40 in 2017, then fell — 2021’s 20 filings dropped to 8 by 2024, a -60% change over that span. However, publication typically lags actual filing by around 18 months, so the apparent drop in 2025-2026 counts partly reflects records that have not published yet rather than a genuine collapse in activity. A fair read of momentum should wait for 2025 to fully populate.

US9732313B2, held by Biovest International and granted in 2017, covers a bioreactor for producing virus and virus-like particles and methods for regulating concentrations of molecules that inhibit viral yield within the extracapillary space of a hollow-fiber bioreactor. Its claims sit on the operational zone that much of the surrounding sensor and connector activity also targets, making it a reference point for freedom-to-operate checks in virus and vaccine production applications specifically, rather than for hollow-fiber culture generally.