July 21, 2026 admin Uncategorized

Complete Guide to Organoid Culture Media: Growth Factors and Protocols

Introduction to Organoids and Their Revolutionary Impact

In the rapidly advancing field of biomedical research, the shift from traditional two-dimensional (2D) cell cultures to three-dimensional (3D) models has been nothing short of transformative. At the absolute forefront of this 3D revolution are organoids—microscopic, self-organizing, three-dimensional cellular structures grown in vitro that closely mimic the complex spatial architecture, diverse cellular composition, and functional characteristics of their corresponding in vivo organs. When we examine the intricate dependencies and biological requirements of these advanced systems, the role of precisely calibrated organoid culture growth factors becomes unequivocally paramount. Without these biochemical cues, the formation of these complex mini-organs would simply be impossible.

Organoids are fundamentally revolutionizing how we approach various critical facets of biological science and modern medicine. In the realm of drug discovery and high-throughput screening, traditional 2D models and standard animal testing protocols often fail to accurately predict human responses, leading to staggeringly high attrition rates in clinical trials. Organoids bridge this crucial translational gap by providing highly predictive, physiologically relevant human tissue models. This is particularly timely and relevant with the recent passage of the FDA Modernization Act 2.0 in the United States. This landmark legislation explicitly authorizes the use of certain scientifically proven alternatives to animal testing, including advanced cell-based assays and microphysiological systems like organoids, to investigate the safety and effectiveness of a drug candidate before it enters clinical trials. This legislative shift is widely expected to significantly accelerate the adoption of organoid technologies in global pharmaceutical pipelines, solidifying their place as an indispensable tool in the future of drug development.

Furthermore, organoids are the foundational cornerstone of the emerging personalized medicine paradigm. By generating patient-derived organoids (PDOs) from a minimally invasive biopsy of an individual’s healthy or diseased tissue (such as a solid tumor), clinicians and researchers can create an ex vivo avatar of the patient’s specific biology. This groundbreaking approach allows for the high-throughput, empirical screening of various therapeutic agents to identify the most effective and least toxic treatment regimen tailored specifically to that individual’s unique genetic and phenotypic makeup. This is a profound game-changer in oncology, infectious disease modeling, and rare disease management.

However, the successful generation, long-term maintenance, and controlled expansion of these highly complex 3D structures depend entirely on the nuanced biochemical cues provided in their microenvironment. This is precisely where the formulation of the culture medium, driven by specific, high-quality organoid culture growth factors, becomes the critical determinant of experimental success. The extracellular matrix (ECM, often Matrigel, Cultrex, or defined synthetic hydrogels) provides the essential physical scaffold and biomechanical support, while a carefully orchestrated cocktail of growth factors, inhibitors, and small molecules directs the stem cells to proliferate, undergo multilineage differentiation, and self-organize into organized structures.

Essential Growth Factors for Organoid Culture

The development of robust, reproducible organoid culture systems relies heavily on deeply understanding the niche signals that maintain and regulate adult stem cells in their native in vivo environment. These crucial signals are replicated in vitro using specific, highly purified recombinant proteins. Below is a comprehensive table detailing the essential organoid culture growth factors commonly utilized across various established protocols, highlighting their mechanisms of action and typical usage.

Growth Factor	Function & Biological Mechanism	Typical Concentration	Common Organoid Types	Key References
Wnt3a	Activates the canonical Wnt/β-catenin signaling pathway. Crucial for maintaining the stem cell niche, driving cellular proliferation, and preventing premature differentiation. Acts as the primary driver for stemness in many epithelial tissues.	30-100 ng/mL (or widely used as conditioned media from L-Wnt3a cells)	Intestinal, Colon, Liver, Stomach, Pancreatic, Endometrial	Sato et al. (2009), Barker et al. (2010)
R-spondin 1 (RSPO1) / R-spondin 3	Potentiates canonical Wnt signaling by binding to LGR4/5/6 receptors and neutralizing the transmembrane E3 ubiquitin ligases ZNRF3 and RNF43. This prevents the degradation of Wnt receptors, massively amplifying Wnt sensitivity. Absolutely essential for robust LGR5+ stem cell maintenance in vitro.	250-500 ng/mL (or as conditioned media)	Intestinal, Colon, Liver, Stomach, Pancreatic, Ovarian, Fallopian tube	Kim et al. (2005), Sato et al. (2011)
Noggin	A potent antagonist of Bone Morphogenetic Proteins (BMPs). By binding and neutralizing BMP ligands (like BMP4), Noggin inhibits BMP signaling which would otherwise forcefully drive terminal differentiation and lead to the rapid exhaustion of the stem cell pool.	100-200 ng/mL (or as conditioned media)	Intestinal, Colon, Prostate, Fallopian tube, Esophageal	Haramis et al. (2004), Sato et al. (2009)
EGF (Epidermal Growth Factor)	Binds the EGFR (ErbB1) to robustly activate the MAPK/ERK and PI3K/AKT downstream signaling pathways. Provides a fundamental mitogenic (proliferation) signal essential for the survival and expansion of almost all epithelial cell types in culture.	20-50 ng/mL	Almost all epithelial organoids (Intestinal, Liver, Lung, Mammary, Prostate)	Sato et al. (2009), Huch et al. (2013)
FGF-10 (Fibroblast Growth Factor 10)	Binds with high specificity to the FGFR2b receptor isoform found on epithelial cells. It is critically important for directing branching morphogenesis, stimulating epithelial cell proliferation, and ensuring survival during the development of specific branching organs.	50-100 ng/mL	Lung, Pancreatic, Stomach, Lacrimal gland, Salivary gland	Dye et al. (2015), Huch et al. (2013)
HGF (Hepatocyte Growth Factor)	Binds exclusively to the c-Met receptor tyrosine kinase. It is a powerful pleiotropic factor crucial for cell proliferation, survival, motility, and complex morphogenesis, playing a particularly central role in the regeneration and culture of hepatic and biliary systems.	25-50 ng/mL	Liver (hepatic and biliary), Pancreatic	Huch et al. (2013), Broutier et al. (2016)

The Standard Cocktail: Deep Dive into WENR Media Composition

The foundation of many adult stem cell-derived organoid cultures, particularly those of gastrointestinal origin (such as the small intestine and the colon), is a specific, highly optimized combination of growth factors affectionately known in the field as the “WENR” cocktail. This widely recognized acronym stands for the four critical protein components that collectively and faithfully recreate the dynamic stem cell niche in vitro:

Wnt3a (Wnt Family Member 3A)
EGF (Epidermal Growth Factor)
Noggin
R-spondin 1 (or alternatively, R-spondin 3)

The groundbreaking development of the WENR formulation, pioneered primarily by the Clevers Laboratory (Sato et al., 2009), marked an absolute watershed moment in 3D biology. Before this discovery, maintaining adult primary epithelial stem cells in culture for extended periods was considered nearly impossible. Let’s delve into the underlying biology to understand why these specific organoid culture growth factors are so exquisitely synergistic.

In the native mammalian intestinal crypt, Lgr5+ adult stem cells reside securely at the base, constantly dividing to steadily repopulate the rapidly turning over intestinal lining. This specialized niche microenvironment is characterized by a high, sharply defined gradient of Wnt signaling (highest at the crypt base) and a corresponding low gradient of BMP signaling. Wnt3a is introduced to the culture media to provide the essential baseline Wnt signal that directly drives stem cell self-renewal and pluripotency. However, researchers quickly discovered that Wnt3a alone is insufficient for robust, long-term culture.

This is precisely where R-spondin 1 becomes the linchpin of the system. Functioning as a highly potent Wnt agonist, R-spondin 1 binds specifically to LGR5 (and related LGR4/6) receptors expressed abundantly on the stem cells. This binding event massively amplifies the baseline Wnt signal by preventing the turnover of Wnt receptors at the cell surface, thereby sensitizing the cells to even incredibly low levels of ambient Wnt3a. This synergistic Wnt amplification is absolutely and strictly required to robustly maintain the Lgr5+ stem cell identity over multiple serial passages spanning months in culture.

Conversely, Bone Morphogenetic Proteins (BMPs), which are often present in serum supplements or secreted by the cells themselves, strongly promote the terminal differentiation of these stem cells into specialized mature cell types (like absorptive enterocytes or secretory goblet cells). While differentiation is necessary for forming a complete organoid, uncontrolled BMP signaling would rapidly deplete the valuable stem cell pool, causing the culture to crash. Therefore, Noggin is added continuously to the media to robustly antagonize and silence BMP signaling, keeping the stem cells in an undifferentiated, highly proliferative state during the expansion phase. Finally, EGF is included to provide the necessary ubiquitous mitogenic drive, ensuring the epithelial cells continue to actively divide and expand to form the characteristic macroscopic 3D organoid structures.

While standard WENR media is largely sufficient for establishing and maintaining basic mouse small intestinal organoids, human organoids and other diverse tissue types generally require significant further refinement. These specialized protocols typically involve adding tissue-specific factors (like FGFs, HGF, or specialized small molecule inhibitors) to meticulously mimic the unique biochemical signature of that specific organ’s niche.

Organoid Type-Specific Protocols and Formulations

While the fundamental principles of mimicking the stem cell niche remain constant across the field, the specific, required cocktail of organoid culture growth factors varies significantly depending on the tissue of origin and the desired developmental state. Below is a comprehensive table outlining the primary growth factor requirements and critical small molecule supplements for some of the most widely used organoid models today.

Organoid Type	Protocol Nuances & Media Strategy	Required Growth Factors & Key Small Molecules
Human Small Intestinal / Colon	Builds upon the standard WENR base but requires additional niche factors and kinase inhibitors for long-term human epithelial stability.	Factors: Wnt3a, R-spondin 1, Noggin, EGF, Prostaglandin E2 (PGE2), Gastrin. Small Molecules: Nicotinamide, A83-01 (ALK4/5/7 inhibitor), SB202190 (p38 MAPK inhibitor).
Liver (Hepatic & Cholangiocyte)	Typically utilizes a biphasic protocol. Expansion media requires strong proliferative signals, while differentiation into mature hepatocytes requires the distinct withdrawal of Wnt and addition of maturation cytokines.	Expansion: R-spondin 1, EGF, HGF, FGF-10, Noggin. Key Supplements: A83-01, Forskolin. Differentiation: Withdrawal of R-spondin/Wnt. Addition of DAPT (Notch inhibitor), Dexamethasone, Oncostatin M (OSM).
Lung (Alveolar / Airway)	Highly dependent on robust FGF signaling to drive essential branching morphogenesis and distal lung specification.	Factors: FGF-10, FGF-7 (KGF), EGF, Noggin, R-spondin 1. Supplements: Y-27632 (ROCK inhibitor) is often critical for initial single-cell survival post-dissociation.
Pancreatic (Ductal)	Similar conceptually to liver protocols but with distinct niche requirements tailored to the pancreatic ductal environment.	Factors: R-spondin 1, EGF, FGF-10, Noggin, Gastrin. Supplements: Nicotinamide, A83-01, Prostaglandin E2 (PGE2).
Brain (Cerebral) from iPSCs	These are not derived from adult tissue but represent directed differentiation from pluripotency. Involves a highly complex, multi-stage timeline mimicking embryonic development.	Varies drastically by stage: Initial neural induction relies heavily on dual SMAD inhibition (using Dorsomorphin/Noggin + SB431542). Later maturation stages use bFGF (FGF-2), EGF, BDNF, and GDNF to promote neuronal survival and axon guidance.

Quality Matters: The Profound Impact of Recombinant Proteins on Reproducibility

One of the most persistent and significant challenges currently facing the field of organoid research is ensuring rigid reproducibility between independent experiments and standardizing results across different global laboratories. A major, often overlooked source of this frustrating variability stems directly from the quality and consistency of the organoid culture growth factors utilized in the media formulations. Organoids, by their very nature, are exquisitely sensitive to their surrounding microenvironment. Even minor fluctuations in the specific bioactivity, concentration, or purity of supplemented proteins can profoundly and permanently alter their growth kinetics, spontaneous differentiation status, and overall viability.

When selecting recombinant proteins for critical organoid culture applications, researchers must meticulously evaluate several key quality attributes rather than simply shopping by name and price alone:

Lot-to-Lot Variability and Manufacturing Consistency: Inconsistent or poorly controlled manufacturing processes can lead to dramatic differences in protein activity between different production batches (lots). This frustrating reality necessitates time-consuming, expensive titration experiments every time a new lot is purchased just to maintain consistent organoid growth baselines. Premium, high-quality manufacturers employ stringent, heavily documented quality control (QC) measures to ensure absolute minimal lot-to-lot variation, allowing researchers to develop truly standardized, locked-down protocols.
Specific Bioactivity and Potency: It is a fundamental truth in biochemistry that not all recombinant proteins are created equal. A protein might be physically present in the vial as quantified by mass, but entirely structurally inactive due to severe misfolding during bacterial expression or damage from harsh purification processes. The specific activity, which must be determined via highly sensitive, functionally relevant cell-based assays (e.g., measuring the dose-dependent proliferation of a specific reporter cell line), must be verified to ensure the protein is functionally potent. Low bioactivity means the researcher must add significantly more protein mass to achieve the desired biological effect, radically increasing experimental costs and potentially introducing toxic off-target effects from accumulating contaminants in the media.
Endotoxin Levels and Immunogenic Contaminants: Endotoxins (specifically lipopolysaccharides, or LPS) are structural remnants of bacterial cell walls. They are extremely common contaminants when recombinant proteins are expressed in standard E. coli systems. Endotoxins are incredibly potent immune stimulators and can severely, and often silently, negatively impact the growth, viability, and delicate phenotypic stability of primary stem cells and complex organoids. High-quality growth factors intended for 3D culture must possess stringently low, verified endotoxin levels (typically strictly <0.1 EU/μg, or ideally <0.01 EU/μg for the most sensitive applications like immunology co-cultures).
Expression System and Post-Translational Modifications (PTMs): The choice of the host expression system (e.g., E. coli, yeast, insect cells, or mammalian cells) drastically affects the resulting protein’s critical post-translational modifications, most notably complex glycosylation patterns. Mammalian-expressed proteins generally possess PTMs that most closely resemble native human proteins. This authentic glycosylation often results in vastly superior protein stability in warm culture media, correct 3D folding, better solubility, and significantly higher in vivo-like receptor binding and bioactivity compared to their simpler, unmodified bacterially expressed counterparts.

The Great Debate: Conditioned Media vs. Purified Recombinant Proteins

Historically, primarily due to the exceptionally high cost and technical difficulty of purifying certain recombinant proteins (especially the lipid-modified Wnt3a and heavily glycosylated R-spondin 1), many pioneering laboratories have relied extensively on the use of “conditioned media” (CM). CM is produced by maintaining cultures of specially engineered, proprietary cell lines (such as L-cells or HEK293 variants) that stably express and secrete the desired growth factor directly into their own culture medium. This enriched medium is then harvested, filtered to remove cells, and added volumetrically to the organoid culture.

The Case for Conditioned Media (CM)

Pros: The undeniable primary advantage is cost. CM is significantly more cost-effective for laboratories engaging in large-scale, continuous, or high-throughput culturing where enormous volumes of media are consumed daily. Validated protocols for producing Wnt3a and R-spondin 1 CM are widely published and heavily utilized in academia.
Cons: The major downfall is severe, inherent variability. The actual concentration of the target active growth factor in the CM is usually entirely unknown and fluctuates wildly between different production batches, highly dependent on the transient health, confluency, and passage number of the producing cells. Furthermore, CM contains a massively complex, entirely undefined “soup” of serum proteins (if grown with FBS), random metabolic byproducts, exosomes, and hundreds of other off-target secreted factors from the host cells. This undefined complexity introduces massive confounding variables, hinders experimental reproducibility, and makes elucidating specific signaling pathways nearly impossible. Furthermore, it is incredibly challenging to scale up and standardize CM production to meet the rigorous regulatory standards required for clinical or GMP-compliant settings.

The Transition to Purified Recombinant Proteins

Pros: Purified proteins offer defined, precise, and completely controllable conditions. Researchers know exactly what molar concentration of each specific factor is being added to their media, effectively eliminating a major, frustrating source of experimental variability. They lack the vast undefined components found in CM, providing a pristine, clean, and highly controlled experimental system. Utilizing highly pure recombinant proteins is an absolute, non-negotiable prerequisite for transitioning experimental protocols to xeno-free, chemically defined, and clinically compliant standards necessary for therapeutic applications.
Cons: The primary historic drawback has been the substantial cost barrier. Furthermore, some highly complex proteins, particularly Wnt3a, are notoriously difficult to purify, concentrate, and stabilize in an active, soluble form due to their highly hydrophobic nature and essential lipid modifications, historically leading to poor commercial availability of highly active forms.

However, as the organoid field rapidly matures and aggressively moves towards translational applications—such as personalized cell therapies, standardized automated drug screening platforms, and engineered tissue grafts—the overarching shift towards utilizing highly pure, defined recombinant organoid culture growth factors is accelerating rapidly, moving away from the legacy of undefined conditioned media.

Boston Molecules Z-Active® Proteins: Elevating Organoid Culture

To directly address the critical, unmet need for highly active, rigorously consistent, and completely defined components in the demanding field of 3D biology, Boston Molecules has expertly developed the Z-Active® line of premium recombinant proteins. Engineered specifically from the ground up to overcome the common historical pitfalls of standard, generic cytokines and growth factors, Z-Active® proteins provide the unwavering, robust biochemical foundation required for truly reproducible, high-tier organoid research.

Our uncompromising commitment to scientific quality ensures that absolutely every single lot of Z-Active® organoid culture growth factors meticulously meets the most rigorous, industry-leading standards:

Authentic Mammalian Expression: Unlike many generic, cheaper proteins expressed rapidly in E. coli, our key organoid signaling factors are expressed exclusively in highly optimized, proprietary mammalian cell lines (such as human HEK293 or engineered CHO cells). This critical choice ensures authentic, human-like post-translational modifications (including complex glycosylation), which is absolutely crucial for maintaining native protein conformation, ensuring optimal receptor binding kinetics, and achieving maximum, long-lasting in vitro bioactivity.
Pristine Tagless Formulation: Many commercial proteins retain bulky purification tags (such as poly-His-tags, GST-tags, or large Fc-fusions) to ease the manufacturer’s purification process. However, these artificial, non-native appendages can severely structurally interfere with proper receptor binding, artificially alter the protein’s half-life in culture, or even unexpectedly induce unwanted, confusing immunogenic responses in sensitive co-culture models. Z-Active® proteins are meticulously engineered and enzymatically processed to be completely tag-free, providing researchers with the native, pristine, untethered molecule for authentic, interference-free physiological signaling.
Exceptional Bioactivity & Unmatched Lot-to-Lot Consistency: We employ advanced, stringently controlled, and heavily monitored manufacturing processes. Most importantly, we rigorously validate every single batch with highly sensitive, functionally relevant cell-based bioassays. This rigorous QA/QC pipeline guarantees that you receive the exact same powerful, consistent performance every single time you order, completely eliminating the frustrating need to constantly recalibrate your delicate protocols with every new vial.
Ultra-Low Endotoxin Guarantee: Our specialized, multi-step purification protocols consistently and reliably achieve industry-leading, ultra-low endotoxin levels (routinely <0.01 EU/μg). This absolute purity ensures your highly sensitive primary stem cell cultures and complex organoid models remain entirely healthy, unperturbed, and free from artifactual inflammatory responses.

Whether your laboratory is working on establishing foundational, highly robust intestinal organoids utilizing our uniquely potent R-spondin 1 and Noggin, or you are developing highly complex, multi-lineage respiratory models requiring precise, sustained FGF-10 signaling, Boston Molecules provides the critical, high-performance ingredients required for your success. Elevate the reproducibility, reliability, and biological relevance of your 3D models today.

Explore our comprehensive, curated portfolio tailored specifically for 3D biology at our Organoid Culture Solutions page, or browse our complete, extensive catalog of high-purity Growth Factors to discover the precise Z-Active® proteins perfectly suited for your specific and demanding protocols.

Expert Guide: Troubleshooting Common Organoid Culture Issues

Even when armed with the best-published protocols and the absolute highest quality reagents available, successfully cultivating and maintaining long-term organoids can be a daunting and highly challenging endeavor. Below is a detailed troubleshooting guide addressing the most frequent and frustrating issues specifically related to organoid culture growth factors and media formulation optimization.

Observation / Common Problem	Potential Biological Causes	Recommended Expert Solutions
Organoids fail to form completely after initial seeding from single cells or crypts; cells undergo rapid apoptosis (death).	Lack of critical anti-apoptotic survival signals (e.g., ROCK inhibitor missing during dissociation stress); Insufficient core growth factor activity (especially EGF/Wnt); Poor Matrigel/ECM quality or inappropriate polymerization temperature.	Ensure Y-27632 (a potent ROCK inhibitor) is supplemented in the media at 10 μM for the first 48-72 hours post-seeding. Verify the specific bioactivity and correct molar concentration of critical factors like EGF and Wnt3a. Rigorously check ECM lot numbers, protein concentration, and ensure proper handling on ice to prevent premature gelation.
Organoids form initially but dramatically slow growth or stop entirely after a few passages; structures become dark, dense, and necrotic in the center.	Classic stem cell exhaustion. This is usually due to vastly insufficient Wnt pathway signaling over time, or excessive, uncontrolled differentiation driven by uninhibited BMPs.	Immediately increase the concentration, or the frequency of media changes, for R-spondin 1 and Wnt3a supplementation. Ensure Noggin levels are adequately high to strongly suppress BMP-driven differentiation. Strongly consider switching from highly variable conditioned media to potent, defined recombinant proteins to ensure consistent dosing and rescue the culture.
Organoids aggressively lose their characteristic, highly organized morphology (e.g., intestinal organoids lose their classic “crypt-villus” budding structure and degenerate into simple, smooth, undifferentiated spherical cysts).	Severe imbalance in the critical Wnt/differentiation axis. Vastly excessive Wnt signaling (often from over-supplementation) can cause hyper-proliferative cystic growth devoid of structure; conversely, too little Wnt causes growth arrest.	Carefully titrate Wnt3a and R-spondin 1 concentrations downward to find the optimal balance for maintaining structure. Verify the biological activity of Noggin. Ensure the base media is exceptionally fresh, as many critical components (like Glutamine and certain vitamins) degrade rapidly at 37°C over time.
High, frustrating variability in growth rates and organoid sizes between different wells in the exact same experiment.	Inconsistent, non-homogeneous embedding of cells in the ECM dome (cells settling to the bottom plastic); Rapid degradation of highly unstable growth factors (specifically Wnt3a) in the pre-warmed working media stock.	Ensure cells are thoroughly and evenly mixed in the cold ECM immediately before plating domes. Prepare fresh complete media very frequently (ideally making only what is needed for 1 week maximum) and store aliquots of purified growth factors correctly (usually at -80°C) to strictly prevent freeze-thaw degradation and loss of activity.

Key Scientific References

Sato, T., Vries, R. G., Snippert, H. J., van de Wetering, M., Barker, N., Stange, D. E., … & Clevers, H. (2009). Single Lgr5 stem cells build crypt-villus structures in vitro without a mesenchymal niche. Nature, 459(7244), 262-265. (The foundational paper establishing the WENR protocol).
Barker, N., Huch, M., Kujala, P., van de Wetering, M., Snippert, H. J., van Es, J. H., … & Clevers, H. (2010). Lgr5+ve stem cells drive self-renewal in the stomach and build long-lived gastric units in vitro. Cell stem cell, 6(1), 25-36.
Sato, T., Stange, D. E., Ferrante, M., Vries, R. G., Van Es, J. H., Van den Brink, S., … & Clevers, H. (2011). Long-term expansion of epithelial organoids from human colon, adenoma, adenocarcinoma, and Barrett’s epithelium. Gastroenterology, 141(5), 1762-1772.
Huch, M., Dorrell, C., Boj, S. F., van Es, J. H., Li, V. S., van de Wetering, M., … & Clevers, H. (2013). In vitro expansion of single Lgr5+ liver stem cells induced by Wnt-driven regeneration. Nature, 494(7436), 247-250.
Dye, B. R., Hill, D. R., Ferguson, M. A., Tsai, Y. H., Nagy, M. S., Dyal, R., … & Spence, J. R. (2015). In vitro generation of human pluripotent stem cell derived lung organoids. Elife, 4, e05098.
Broutier, L., Andersson-Rolf, A., Hindley, C. J., Boj, S. F., Clevers, H., Koo, B. K., & Huch, M. (2016). Culture and establishment of self-renewing human and mouse adult liver and pancreas 3D organoids and their genetic manipulation. Nature protocols, 11(9), 1724-1743.
Kim, K. A., Kakitani, M., Binnerts, M. E., Carlson, P. T., Cousens, L. S., Dix, J. C., … & Abo, A. (2005). Mitogenic influence of human R-spondin1 on the intestinal epithelium. Science, 309(5738), 1256-1259.

Disclaimer: All products, reagents, and protocols described herein are intended for Research Use Only (RUO) and are not to be used for diagnostic, therapeutic, or clinical procedures.