Cell and gene therapy (CGT) manufacturing faces significantly more complex contamination control challenges than conventional pharmaceutical production. The combination of living biological materials, ultra-sensitive patients, and tightly regulated cleanroom environments creates a contamination risk profile that demands a more rigorous, layered approach to hygiene and particulate management. The sections below address the most pressing questions Quality, EHS, and Facilities Managers are asking in 2026.
Why is contamination control harder in cell and gene therapy than in traditional pharma?
Contamination control in cell and gene therapy is harder than in traditional pharma because the product itself is a living biological material that cannot be terminally sterilised. Unlike small-molecule drugs or even most biologics, CGT products such as CAR-T cells, viral vectors, and gene-edited constructs are irreversibly damaged by the sterilisation methods that would otherwise eliminate contamination risk.
This single constraint changes everything. In conventional pharmaceutical manufacturing, a terminal sterilisation step provides a final safety net. In CGT, there is no such net. Every contamination event that occurs during the manufacturing process has the potential to render a batch unusable, or worse, to harm a patient who has no other treatment option. The stakes are not just commercial; they are clinical.
The complexity is compounded by the autologous nature of many CGT therapies. When a product is derived from a specific patient’s own cells, cross-contamination between batches is not just a quality failure. It is a patient safety crisis. This demands physical segregation, rigorous gowning protocols, and environmental monitoring standards that go well beyond what most traditional cleanrooms require.
What are the main sources of contamination in cell and gene therapy facilities?
The main sources of contamination in CGT facilities are personnel, equipment surfaces, incoming materials, and the facility environment itself, particularly at entry and transition points. Personnel are consistently identified as the primary contamination vector, contributing particulates, microorganisms, and biological material through movement, skin shedding, and respiratory activity.
Understanding each source category helps facilities prioritise their contamination control investment:
- Personnel traffic: Shoes and wheeled equipment carry particulate matter, microbial load, and chemical residues from uncontrolled external environments directly into cleanroom zones. Studies in contamination science consistently identify floor-level ingress as accounting for the majority of particulate entry into controlled spaces.
- Equipment and materials transfer: Raw materials, single-use components, and equipment entering the facility from outside the controlled zone introduce contamination risk at every transfer point.
- HVAC and airborne particles: Inadequate air handling, pressure differentials, or breaches in the cleanroom envelope allow airborne contaminants to migrate between zones.
- Cross-contamination between batches: In facilities handling multiple patient-derived materials, inadequate segregation between workstations, transfer routes, and gowning areas creates the risk of inter-batch contamination.
- Surfaces and floors at transition zones: Gowning rooms, airlocks, and corridor entry points are high-traffic areas where contamination accumulates and is redistributed unless actively managed.
Addressing floor-level contamination at entry points is particularly critical in CGT facilities because the controlled environment classification often begins at the threshold of a gowning room or airlock. Any particulate or microbial load carried in on footwear or equipment wheels at that point enters the most sensitive zone in the facility.
How do GMP and regulatory requirements shape contamination control in CGT manufacturing?
GMP and regulatory requirements for CGT manufacturing mandate a risk-based, documented approach to contamination control that covers facility design, personnel procedures, environmental monitoring, and the qualification of every control measure in place. Regulatory bodies including the FDA, EMA, and MHRA have all issued guidance specific to advanced therapy medicinal products (ATMPs) that reinforces the need for heightened contamination control standards.
The EU GMP Annex 1 revision, which came into full effect in 2023 and continues to shape facility practices in 2026, introduced the Contamination Control Strategy (CCS) as a mandatory framework. The CCS requires manufacturers to identify all contamination risks, document the controls in place, and demonstrate through validation that those controls are effective. This is not a checkbox exercise. Regulators expect manufacturers to show that their contamination control programme is holistic, integrated, and continuously reviewed.
For CGT facilities specifically, this means that entry point hygiene, gowning procedures, environmental monitoring, and surface decontamination must all be part of a documented and validated system. Facilities that rely on legacy solutions such as disposable sticky mats or footbaths without documented performance data are increasingly exposed during regulatory inspections, as these solutions lack the validated efficacy data that a CCS demands.
What contamination control measures are most critical at facility entry points?
The most critical contamination control measures at facility entry points are those that prevent particulate and microbial ingress before it enters the controlled zone. This means addressing footwear, wheeled equipment, and personnel behaviour at the transition between uncontrolled and controlled spaces, because contamination that enters at the threshold is far harder to manage once it is inside.
Effective entry point control in a CGT facility typically includes a combination of the following:
- High-performance contamination control matting: Reusable polymeric mats at cleanroom entrances, gowning rooms, and airlocks capture particulates and microbial load from shoe soles and equipment wheels before they cross into the controlled zone. Unlike disposable sticky mats, which lose efficacy rapidly and generate significant waste, validated reusable mats maintain consistent performance over their operational life.
- Gowning protocols: Structured, sequenced gowning procedures reduce the transfer of external contamination to cleanroom garments and surfaces.
- Airlock and pressure differential management: Correctly designed airlocks with appropriate pressure cascades prevent airborne contamination from migrating between zones during personnel and material transfer.
- Equipment surface wipe-down procedures: All equipment entering the controlled zone should be decontaminated at the transfer point using validated disinfectants.
- Visitor and contractor management: Clear protocols for non-regular personnel entering the facility reduce the risk of uncontrolled contamination events.
Floor-level control at entry points deserves particular emphasis. With the majority of contaminants entering controlled environments at floor level, the matting system at the threshold of a cleanroom or gowning area is one of the highest-leverage contamination control investments a CGT facility can make.
How should contamination control strategies be validated in a CGT cleanroom?
Contamination control strategies in a CGT cleanroom should be validated by demonstrating, through documented testing and environmental monitoring data, that each control measure performs consistently at or above its claimed efficacy under real operating conditions. Validation is not a one-time event; it is an ongoing process of qualification, monitoring, and review.
A robust validation approach for CGT cleanroom contamination control typically involves:
- Initial qualification: Each control measure, including matting systems, gowning procedures, and cleaning protocols, should be qualified against defined performance criteria before routine use begins. This establishes a baseline and confirms that the measure works as intended.
- Environmental monitoring: Regular air and surface sampling at defined locations, including entry points and high-risk zones, provides ongoing evidence that contamination levels remain within acceptable limits. Trend analysis of this data is essential for identifying emerging risks before they become incidents.
- Periodic revalidation: Changes to facility layout, personnel numbers, traffic patterns, or product types should trigger a review and, where necessary, revalidation of the affected control measures.
- Documentation and traceability: Every element of the validation programme must be fully documented and traceable to the facility’s Contamination Control Strategy. This is the evidence base that regulators will scrutinise during inspections.
For matting systems specifically, validation should include evidence of particulate capture efficiency, antimicrobial performance, and compatibility with the facility’s cleaning and disinfection regime. Suppliers who can provide independent performance data and support the qualification process add significant value in a regulatory context.
What role does sustainability play in contamination control for cell and gene therapy?
Sustainability is increasingly a formal consideration in CGT contamination control, driven by both regulatory pressure and the ESG commitments of the pharmaceutical and biotech organisations operating in this space. The environmental impact of contamination control choices, particularly the reliance on single-use disposable sticky mats, is now a measurable part of a facility’s overall sustainability profile.
Disposable peel-off mats generate substantial volumes of plastic waste. A high-traffic CGT facility can consume thousands of mat layers per year, each destined for landfill. As pharmaceutical companies set science-based emissions and waste reduction targets, procurement decisions around contamination control are coming under greater scrutiny from sustainability and ESG teams alongside Quality and Facilities.
Reusable contamination control solutions offer a more sustainable alternative without compromising performance. A reusable mat system with a lifespan measured in years, rather than hours, eliminates the recurring waste cycle of disposable alternatives while maintaining validated particulate capture performance throughout its operational life. This is not simply an environmental argument; it is a total cost of ownership argument that resonates with both Procurement and Quality stakeholders.
In 2026, facilities that can demonstrate a preference for validated, reusable contamination control solutions are better positioned to meet both their regulatory obligations and their corporate sustainability commitments simultaneously.
How Dycem CleanZone supports contamination control in CGT manufacturing
Dycem CleanZone is a reusable, antimicrobial contamination control mat system engineered for the entry points and transition zones where contamination risk is highest in CGT and other critical manufacturing environments. It is designed to address the specific challenges that Quality and Facilities Managers face when disposable alternatives no longer meet performance, compliance, or sustainability requirements.
Key features relevant to CGT facility managers include:
- Validated particulate capture: Dycem mats capture up to 99.9% of shoe and wheel contaminants, providing documented performance data that supports Contamination Control Strategy requirements.
- Built-in Biomaster antimicrobial protection: Integrated antimicrobial technology reduces microbial load on the mat surface between cleaning cycles, adding an additional layer of hygiene control.
- Reusable and washable construction: CleanZone mats are designed for long-term use, eliminating the waste and recurring cost of disposable sticky mat programmes.
- ISO-certified manufacturing: Produced in compliance with EN ISO 9001 and 14001 standards, supporting supplier qualification and audit readiness.
- Customisable format: Available in sizes and configurations to suit gowning rooms, airlocks, and cleanroom entry corridors specific to CGT facility layouts.
If your facility is reviewing its contamination control programme or preparing for a regulatory inspection, Dycem’s contamination control specialists can provide a free site survey and consultation. Contact the Dycem team to discuss how CleanZone can be integrated into your CGT cleanroom strategy.