LUNA-STEM™: Accurate, Automated Counting of Stem and Nucleated Cells

By Anamta Shehzadi

Posted on July 26, 2025

As regenerative medicine and cellular therapeutics continue to reshape the future of healthcare, the demand for precise, reproducible, and regulatory-compliant cell quantification has never been greater. From stem cell characterization to tissue engineering, the quality of downstream results often hinges on the accuracy of your upstream cell analysis. The LUNA-STEM™ Automated Fluorescence Cell Counter, developed by Logos Biosystems, is uniquely positioned to meet these exacting requirements.

Designed specifically for the quantification of stem and nucleated cells, the LUNA-STEM™ delivers automated, high-fidelity analysis using dual-fluorescence detection—ideal for workflows involving heterogeneous cell populations, stromal vascular fractions (SVF), or primary tissue digests. It brings together the ease of image-based cytometry with the performance necessary for clinical and translational research.

Addressing the Complexity of Stem Cell Preparations

Unlike immortalized cell lines, stem cell populations derived from primary tissues—such as adipose tissue, bone marrow, or umbilical cord blood—are often heterogeneous and low in abundance. Manual counting with a hemocytometer not only consumes time but is notoriously imprecise, especially when non-nucleated cells, red blood cells, and debris are present.

The LUNA-STEM™ eliminates subjectivity from the equation. By using dual-fluorescence staining with Acridine Orange (AO) and Propidium Iodide (PI), the system accurately differentiates between:

Nucleated live cells (AO+)
Nucleated dead cells (AO+/PI+)
Non-nucleated cells (excluded)
Debris (excluded)

This capability is essential for applications such as stromal vascular fraction (SVF) quantification, stem cell isolation, and quality control of cellular therapeutics, where accurate nucleated cell enumeration can directly impact therapeutic outcomes or regulatory acceptance.

Dual-Fluorescence Detection: The Gold Standard

The heart of the LUNA-STEM™ is its dual-channel fluorescence imaging system, combined with a high-resolution optical engine. The system utilizes:

Acridine Orange (AO): a green fluorescent dye that intercalates into nucleic acids, staining both live and dead nucleated cells.
Propidium Iodide (PI): a red fluorescent dye that penetrates only membrane-compromised cells, enabling live/dead discrimination.

By capturing both green and red fluorescence images simultaneously, the LUNA-STEM™ ensures clear, unambiguous differentiation between viable and non-viable nucleated cells. Debris, erythrocytes, and anucleated fragments are excluded from analysis, greatly improving the accuracy of counts derived from complex primary samples.

Optimized for SVF and Adipose-Derived Cell Preparations

The LUNA-STEM™ is widely recognized as the instrument of choice for SVF analysis. Adipose tissue, when digested with collagenase, yields a complex suspension containing adipocytes, red blood cells, nucleated stromal cells, and various progenitors. Conventional trypan blue-based counters often misidentify anucleated cells or lipid droplets, inflating total cell counts and underreporting viability.

In contrast, the LUNA-STEM™ quantifies only nucleated cells—which are the biologically relevant population—using fluorescence detection. The result is a more accurate measure of SVF content, which is essential for both basic research and clinical applications such as autologous stem cell therapy.

Streamlined Workflow, Consistent Output

Using the LUNA-STEM™ is simple and reproducible:

Prepare your single-cell suspension and stain with AO/PI.
Load 10 μL into a reusable or disposable slide.
Insert the slide into the instrument.
Let the onboard software handle focusing, image acquisition, analysis, and reporting.

Results are available in under 30 seconds and include:

Total nucleated cell count
Viable nucleated cell count
Viability percentage
Average cell size and morphology
Annotated images for each channel

This quick, hands-free workflow removes the bottleneck of manual counting while increasing confidence in every data point.

Flexible, Cost-Efficient Consumables

The LUNA-STEM™ supports both disposable slides (ideal for sterility-sensitive or clinical settings) and reusable precision slides, allowing labs to tailor cost and workflow to their needs. This flexibility makes the instrument suitable for:

Academic stem cell labs
GMP-compliant cell therapy manufacturing
Preclinical R&D in regenerative medicine
Orthobiologics and tissue engineering workflows

Unlike flow cytometers, which require complex calibration, skilled personnel, and high sample volumes, the LUNA-STEM™ operates with minimal sample prep, no sheath fluid, and minimal user training.

Data Integrity for Regulated Environments

Whether you’re preparing samples for an IND submission or generating QC metrics for a clinical trial, traceability is non-negotiable. The LUNA-STEM™ provides:

Audit-ready PDF reports
CSV data exports
Fluorescence image archives
User login and session tracking

These features support integration into GMP, GLP, and 21 CFR Part 11-compliant workflows, offering peace of mind for teams operating in regulated environments. Every measurement is image-verified, timestamped, and digitally exportable.

Built-In Intelligence and Automation

The system’s software is designed to make advanced analysis accessible without a steep learning curve. It includes:

Autofocus and auto-analysis
Real-time cell gating and size filtering
Live/dead overlays
Batch processing capability

This intelligent software helps maintain consistency across users, labs, and projects, while reducing hands-on time and variability.

Use Cases Across Regenerative Medicine

The versatility of the LUNA-STEM™ extends across a wide range of translational and clinical research areas:

Application Area	Relevance of LUNA-STEM™
Adipose-Derived Stem Cells	Precise SVF and viability counts after collagenase digestion
Bone Marrow Transplants	Enumeration of viable hematopoietic stem cells
Cartilage and Tendon Repair	Cell quantification from tissue scaffolds or explants
Autologous Cell Therapies	Quality control and dose validation for therapeutic cell suspensions
Ex Vivo Cell Expansion	Monitoring of cell viability and expansion success

Testimonials from Stem Cell Researchers

A clinical-stage biotech firm developing autologous SVF therapies adopted the LUNA-STEM™ to replace manual hemocytometer workflows. After switching, they reported:

A 4x improvement in time efficiency
Elimination of inter-operator variability
Improved regulatory documentation and batch release confidence

Meanwhile, a university-based tissue engineering lab noted that the LUNA-STEM™ allowed them to quantify multiple distinct subpopulations of nucleated cells more accurately than any previous method, leading to higher reproducibility in scaffold seeding experiments.

Conclusion: Raising the Bar for Stem Cell Quantification

The LUNA-STEM™ Automated Fluorescence Cell Counter addresses one of the most persistent challenges in cellular research and regenerative medicine: accurate quantification of nucleated, viable cells from heterogeneous samples. With its powerful dual-fluorescence optics, intelligent software, and user-friendly design, the LUNA-STEM™ sets a new standard for performance and reliability.

Whether you’re working in basic research, translational studies, or clinical product development, this instrument is a cornerstone for standardized, compliant, and confident cell analysis.