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In collaboration with Skroot Laboratories, SMART Sensors have been integrated into the G-Rex platform to provide developers and manufacturers of cell and gene-modified cell therapies (CGT) a non-invasive method of real-time, continuous monitoring of cell growth.
This integrated process analytic technology (PAT) can instantly report the extent of cell growth (or “report the phase of cell growth”) in a CGT drug production process and can inform manufacturers when a CGT drug product has reached the desired quantity of cells necessary to proceed with formulation, fill, and finish.
By integrating SMART technology, G-Rex is the only platform for CGT manufacturing that can avoid intervention when determining cell quantity or allow real-time monitoring of cell growth throughout the production run.
(P/N G281100-CS-SE)
*ETA Q4 2026*
Resonant sensors are passive inductor-capacitor (LC) circuits whose measured resonant frequency shifts when the electrical permittivity of their immediate environment changes. Their utility for wireless monitoring in sealed or otherwise non-vented systems (where direct access to the interior is not practical or permitted) has been documented across several application areas [1,2]. In the specific context of cell culture monitoring, they enable noncontact interrogation of cultures without sampling. Recently, an advancement on the conventional resonant sensor called the SMART (single-use, metabolite absorbing resonant transducer) sensor was introduced [3]. The SMART design incorporates a polymer layer that softens in response to secreted metabolites, amplifying the local permittivity contrast above the conventional resonator and providing >20-fold higher sensitivity to growth dynamics than direct resonant sensing. Physically, the SMART sensor comprises five layers (from fluid-facing side to vessel-facing side): a transduction membrane responsive to secondary metabolites, a polyethylene terephthalate (PET) sheet with engineered voids, a bonding interlayer, a patterned LC resonator (copper coil on polyimide), and a mounting adhesive for vessel attachment (Fig. #a)[4].
As cells grow, secreted secondary metabolites (organic signaling molecules) selectively absorb into the SMART sensor membrane, softening the membrane material such that it partially collapses into engineered voids in the sensor structure (Fig #b). Prior screening work has shown that simple terpenoids, such as prenol, produce strong responses. For T cells, there is evidence of secreted lipid mediators, including eicosanoid derivatives (e.g., prostanoids and leukotrienes), as signaling molecules [5]. We have verified that arachidonic acid (AA), an omega-6 PUFA that is a precursor to eicosanoids, causes a robust sensor response (see SMART G-Rex publication [6]). This is representative of a broad class of secreted organic compounds that these cells produce during active growth that act as a plasticizer on the sensor membrane.
U.S. Department of Health and Human Services Food and Drug Administration
Center for Drug Evaluation and Research (CDER)
Center for Veterinary Medicine (CVM)
Office of Regulatory Affairs (ORA)
Pharmaceutical CGMPs
September 2004
In accordance with previously issued Guidance for Industry from the Food & Drug Administration (FDA), this new integrated process analytic technology (PAT) will help CGT developers and manufacturers:
Moreover, the ability to qualify a multi-drug product ballroom style of production is more of an operational problem than a regulatory one. The SMART G-Rex platform may also serve a crucial function in driving LEAN operations by providing manufacturer’s a simple way to “warehouse” many drug products within the same incubator while maintaining segregration, control, and traceability.
A single incubator stack, like the ones seen above, will be able to comfortably accommodate 54 G-Rex100M-CS nestled next to a SMART continuous reader. This kind of density is unparalleled in cell & gene therapy manufacturing and will be a core driver of logarithmic reductions in drug product cost by amortizing less overhead over more drug products.
In summary, the simple nature of G-Rex has allowed it to become a sophisticated tool that is future-proofed because new innovations, such as SMART sensors, are easily incorporated into novel G-Rex designs without requiring us to fundamentally alter the G-Rex bioreactor design.
Let’s talk more about how ScaleReady can advance your cell and gene therapy research and manufacturing with ingenious efficiency.