Side-by-side guides for the decisions bioprocess engineers actually face. Every comparison includes a decision matrix, use-case fit, vendor landscape, and cost analysis. No paid placements — recommendations are based on published specifications and deployment patterns.
Choose the right in-line, at-line, or non-invasive sensor for your scale and modality. Covers dissolved oxygen, pH, biomass (capacitance vs optical), and process-analytical spectroscopy.
The measurement-principle decision. Optical has replaced polarographic as the cGMP default — no electrolyte, no warm-up, no O₂ consumption, better CIP/SIP durability. Polarographic still wins on response time and capital cost for high-OUR microbial.
Sensors · pHThe pH sensor measurement-principle decision. Glass electrodes win on accuracy (0.044 vs 0.072 pH discrepancy in the Fratz-Berilla 2024 head-to-head) and dynamic range; optical wins where the vessel is single-use because no glass-electrode form factor can be pre-integrated into a sealed gamma-sterilised bag.
Sensors · CO2The dissolved CO2 sensor measurement-principle decision. Severinghaus electrodes (Mettler InPro 5000i) own the cGMP installed base and the wider 0–1000 mbar range; solid-state mid-IR optical (Hamilton CO2NTROL) eliminates electrolyte refills for new stainless-steel builds; HPTS-dye optical (PreSens) is the only realistic option in single-use bags.
Sensors · Glucose · PATThe glucose monitoring placement decision. Inline Raman (Resolution Spectra ProCellics, Endress+Hauser Kaiser, Tornado HyperFlux) drives a 15-minute closed-loop feedback into the bioreactor controller; at-line YSI 2900D / Nova BioProfile Flex2 / Cedex Bio HT delivers ±2% reference accuracy in 60 seconds per aliquot. CHO commercial mAb runs both — Raman for control, YSI for the daily reference check.
Sensors · DO · VendorThe form-factor decision for optical DO. VisiFerm is an insertable probe with integrated Arc transmitter for reusable stainless steel vessels; PreSens is a gamma-sterilised spot glued inside single-use bags. Same physics, different vessels.
Sensors · DO · VesselThe vessel-driven sensor decision. Single-use DO spots come pre-integrated in Sartorius, Thermo, Cytiva bags; reusable probes dominate stainless steel. Scope explicitly excludes pulse oximeters and automotive sensors.
Sensors · BiomassCapacitance (Aber FUTURA, Hamilton INCYTE) measures viable cell volume via RF impedance — the cGMP standard for mAb fed-batch feed control. Optical turbidity is cheaper but can't distinguish viable from dead cells.
Sensors · PATThe PAT analyzer decision. Raman wins on glucose, lactate, antibody in aqueous culture (the Paik 2018 parallel comparison); NIR wins on water content, glutamine, ammonium, and UF/DF monitoring.
Upstream operating mode and facility architecture decisions. Covers batch vs fed-batch vs perfusion, single-use vs stainless steel, and their economic crossover points.
The facility-architecture decision that determines your sensor choice, cleaning validation scope, and CapEx. Crossover point typically 2,000-5,000 L working volume depending on batch frequency and product lifetime.
Process ModeThe upstream operating-mode decision. Volumetric productivity data, COGS analysis, hybrid intensified approaches for mAb. Triadic comparison with real-world case study data.
EconomicsThe manufacturing-architecture cost comparison. Capital intensity, operational complexity, and regulatory risk traded off across batch and continuous biomanufacturing approaches.
Perfusion · Cell RetentionThe cell retention device decision for perfusion bioreactors. ATF (Repligen XCell ATF) holds mAb sieving at 88-95% across full runs thanks to alternating diaphragm flow; peristaltic-pump TFF decays 95% to 52% from cell-lysis fouling, but a centrifugal-pump TFF (Levitronix) closes the gap and integrates directly into continuous downstream.
Process IntensificationThe process intensification decision for CHO mAb fed-batch. Intensified fed-batch (high inoculation density 5-20 million cells/mL via N-1 perfusion seed) roughly doubles titer in the same N-stage vessel — 8-12 g/L vs 4-6 g/L, in a 10-12 day run vs 14-15 day standard. Capex of $300-800k per seed train ATF/TFF retrofit. Decision matrix for capacity-constrained mAb, greenfield ≥500 kg/yr, and clinical-to-commercial scale-up.
Promoter, vector, and host-strain decisions upstream of every recombinant protein run. Strength, leakiness, copy-number, and host-strain compatibility tradeoffs.
The Bioreactor Sensor Selection Tool takes 6 questions about scale, modality, vessel, parameters, environment, and budget — and returns ranked sensor recommendations with vendor links. Covers every comparison above, plus CO₂, temperature, and glucose.