Every wound dressing that reaches a clinical setting is the product of dozens of material decisions made long before it was packaged and sterilized. Among these decisions, none carries more consequence than the selection of the wound contact layer — the fabric that sits directly against the wound bed and remains there until the next dressing change. That choice determines how effectively exudate is managed, whether the dressing sheds fibers into the wound, whether the fabric holds together when saturated, and whether bacteria colonizing the wound surface encounter a material that actively works against them.
Antibacterial spunlace nonwoven has become the substrate of choice for wound contact layers in modern advanced dressing design, and with good reason. This article addresses the full technical picture: why the fabric works, how its specifications map to clinical requirements, how antibacterial functionality is engineered into the structure, and what wound dressing converters and medical device developers need to evaluate when selecting a qualified substrate supplier.
The wound contact layer is not a passive component. It is the functional interface between a living wound bed and the external wound management system, and its material properties directly influence three clinical outcomes: infection risk, healing rate, and patient comfort at dressing changes.
Infection control begins at the fabric level. A wound contact layer that sheds loose fibers deposits potential foreign body irritants and bacterial attachment sites directly into the wound. A fabric that does not absorb exudate efficiently allows fluid to pool at the wound surface, creating the warm, moist, protein-rich environment in which bacterial biofilm formation accelerates. A fabric that adheres to granulating tissue causes trauma and re-injury at every dressing change, disrupting the healing surface and introducing a new inflammatory response.
Each of these failure modes is a material specification failure, not a clinical technique failure. For wound dressing product developers, this means that fabric selection is inseparable from clinical performance claims. The Medical Series produced by Zhejiang Aojia Nonwoven Technology Co., Ltd. — a spunlace hydroentangled nonwoven manufacturer based in Jiaxing, Zhejiang, China — is engineered specifically to address these clinical requirements at the substrate level, before antibacterial chemistry is introduced.
The wound dressing substrate market has historically used three broad categories of textile materials: woven gauze, thermally or chemically bonded nonwovens, and hydroentangled (spunlace) nonwovens. Understanding why spunlace consistently outperforms the alternatives in clinical wound care applications requires a direct comparison across the properties that matter most.
Woven gauze — the traditional wound care fabric — is produced by interlacing yarns in an orthogonal grid. The cut edges of a gauze fabric are not mechanically stabilized, which means individual fibers and yarn segments are released continuously as the gauze is handled, applied, and removed. Lint deposition from woven gauze in wound beds is a well-documented clinical issue. Gauze also lacks wet strength parity with dry strength, and its open structure provides poor resistance to fluid wicking in a controlled direction — fluid moves freely through the gauze in multiple planes rather than being drawn consistently toward a secondary absorbent layer.
Bonded nonwovens — whether thermally fused with a binder fiber or chemically bonded with an acrylic or latex adhesive system — introduce chemical substances into the fabric structure that may not be inert at the wound interface. Chemical binders in particular carry extractable and leachable substance risk that complicates ISO 10993 biocompatibility testing and can cause skin sensitization in susceptible patients. Thermal bonding limits fiber choice to thermoplastic materials, excluding highly absorbent cellulosic fibers from the base construction.
Spunlace nonwoven for wound dressings is manufactured by directing high-pressure water jets through a loosely arranged fiber web, causing fibers to mechanically interlock with one another without binder, adhesive, or thermal fusion. The result is a structure where every fiber is anchored within the three-dimensional entanglement network. Loose fiber ends are eliminated. The fabric is inherently lint-free. No chemical is introduced during manufacturing that was not already present in the raw fiber. The fabric can incorporate highly absorbent cellulosic fibers alongside structural polyester. And the entanglement structure provides wet strength that is proportionally closer to dry strength than any alternative nonwoven manufacturing route can deliver with the same fiber mix.
These are not marginal improvements. For a wound contact layer that will be saturated, removed under tension, and expected to come away cleanly from a granulating wound surface, the hydroentanglement structure is a fundamental enabler of clinical safety.
The standard fiber blend used in Aojia's wound dressing substrate — 70% viscose / 30% polyester (70% Viscose / 30% PET) — is not an arbitrary commercial compromise. Each component contributes a specific and necessary performance function, and the 70/30 ratio reflects the clinical balance between absorbency and structural integrity that wound care applications demand.
Viscose is a regenerated cellulose fiber produced from wood pulp. Its molecular structure contains a high density of hydroxyl groups that form hydrogen bonds with water molecules, making viscose among the most hydrophilic fibers available for nonwoven manufacturing. A standard textile-grade viscose fiber absorbs 11–13% of its weight in moisture at standard atmospheric conditions — approximately three to four times the moisture regain of polyester. In a wound dressing context, this translates to rapid uptake of wound exudate from the wound surface, drawing fluid away from the wound bed and maintaining the moist wound environment that supports epithelialization. Viscose also has a naturally soft hand, which is important for patient comfort, particularly in dressings used on sensitive periwound skin or in pediatric applications.
However, viscose loses significant tensile strength when wet. A viscose-only hydroentangled fabric exposed to wound exudate or saline can lose 40–60% of its dry tensile strength upon saturation, making it structurally unreliable for removal from a moist wound without fragmentation. The 30% polyester component resolves this. Polyester (PET) is hydrophobic — it does not absorb water and does not weaken when saturated. Within the entangled fiber matrix, polyester fibers provide the structural backbone that maintains fabric integrity under wet conditions, ensuring that a saturated wound contact layer can be removed from the wound surface as a single intact piece rather than fragmenting and leaving residue in the wound.
The 70/30 ratio maximizes absorbent function while preserving the minimum polyester content required for clinically acceptable wet tensile performance. Custom ratios — higher viscose for specialty high-absorbency products, higher polyester for reinforced substrates — are available through Aojia's custom development capability, discussed in Section 11.
Standard spunlace fabric provides the structural platform for wound care performance. Antibacterial functionality is layered onto this platform through chemical treatment, fiber modification, or fiber blend modification. Three antibacterial systems are primarily used in wound dressing substrates, each with distinct performance profiles, regulatory positioning, and clinical considerations.
Silver-based antibacterial treatment is the most clinically established system for wound care. Ionic silver (Ag⁺) disrupts bacterial cell membranes, inhibits enzyme systems essential for bacterial metabolism, and interferes with DNA replication — a multi-mode mechanism of action that reduces the probability of resistance development. Silver can be incorporated into wound contact layer fabric through nano-silver particle application to fiber surfaces, silver-salt impregnation of the fiber matrix, or silver-containing fiber (such as silver-coated polyamide) blended into the base web. The release profile — how quickly ionic silver is released in the presence of wound fluid — determines both efficacy and biocompatibility risk, and is subject to evaluation under ISO 10993-12 (sample preparation) and ISO 10993-5 (cytotoxicity) as part of the biocompatibility assessment for EU MDR compliance.
Chitosan-based antibacterial treatment uses a naturally derived biopolymer derived from crustacean shell chitin. Chitosan carries a positive surface charge at wound pH that disrupts negatively charged bacterial cell membranes, producing a broad-spectrum bacteriostatic effect. Its additional biological properties — including haemostatic activity and stimulation of macrophage activity — make it a clinically attractive option for wound care specifically, where it contributes to both infection control and wound healing promotion simultaneously. Chitosan is inherently biocompatible and biodegradable, which simplifies the biocompatibility pathway under ISO 10993. Its principal regulatory challenge is demonstrating consistent release kinetics in a complex wound environment across the intended dressing wear time.
Polyhexamethylene biguanide (PHMB) is a polymeric biocide that disrupts bacterial cell membranes through electrostatic interaction and is used extensively in wound irrigation and wound contact layer applications. It demonstrates broad-spectrum efficacy against Gram-positive and Gram-negative bacteria including MRSA, and has a well-characterized clinical safety profile with low skin sensitization risk at concentrations used in wound care. PHMB-treated fabrics are commonly used in chronic wound management protocols. Regulatory positioning in the EU requires careful distinction between PHMB as a medicinal product constituent and as a preservative or biocidal component in a medical device — the applicable regulatory pathway determines the documentation and clinical evidence requirements.
All three antibacterial systems are compatible with the spunlace hydroentangled substrate platform. The choice of system is driven by the clinical indication, the intended market's regulatory framework, and the finished device's risk classification.
Basis weight — expressed in grams per square meter (g/m²) and commonly abbreviated GSM — is the primary specification axis for wound contact layer substrate selection, because it determines both the fabric's absorbent capacity and its physical handling characteristics.
Aojia's wound dressing substrate is available across a 40–60 g/m² range. Within this band, the relationship between GSM and clinical performance is direct and predictable. At 40 g/m², the fabric is lightweight, highly conformable, and well-suited to wound contact layers designed to pass exudate rapidly through to a secondary absorbent pad — the fabric's own absorbent capacity is intentionally limited so that fluid is not retained at the wound surface. This makes 40 g/m² an appropriate specification for dressings targeting low-to-moderate exudate wounds where the primary function of the contact layer is non-adherence and fluid transport.
At 60 g/m², the fabric carries significantly more fiber per unit area, increasing absorbent capacity and providing more substantial physical protection to the wound surface. Heavier GSM fabrics are appropriate for wound contact layers in dressings designed to manage moderate exudate volumes independently of a secondary pad — for example, in self-contained island dressings or in wound care products targeting surgical incision sites where short-term exudate volumes are higher.
Beyond the 40–60 g/m² standard range, Aojia's custom development capability allows basis weight specification outside these limits for applications with specific absorbency or structural requirements.
Wet tensile strength is the mechanical specification that most directly governs wound dressing clinical safety at the point of use. A wound contact layer that fragments during removal from a moist wound bed creates two simultaneous clinical problems: fiber fragments remain in the wound as foreign body material, and the disruption of the wound surface during fragment removal causes trauma to healing tissue.
Wet tensile strength is measured by fully saturating a fabric specimen — typically with saline or distilled water — and then applying a tensile load to a defined test width (typically 50 mm) in both the machine direction (MD) and the cross direction (CD) until the specimen ruptures. The force at rupture, expressed in Newtons per 50 mm, is the wet tensile strength value. For medical wound contact layers, minimum values are set by internal quality specifications and by applicable harmonized standards, and both MD and CD values must meet minimum thresholds independently — because the mechanical stresses experienced during dressing removal act in multiple directions simultaneously.
The 70% viscose / 30% polyester fiber blend in Aojia's wound dressing substrate is specifically formulated to maintain clinically acceptable wet tensile performance across the 40–60 g/m² basis weight range. The polyester content, as discussed in Section 3, is the primary determinant of wet strength; the hydroentanglement process parameters — water jet pressure, jet density, and number of hydroentanglement passes — determine how effectively that polyester content is mobilized within the three-dimensional fiber matrix to provide structural continuity when the fabric is wet.
Burst strength — resistance to perpendicular hydrostatic pressure — is the secondary mechanical specification relevant to wound contact layers used under compression systems, where bandage pressure applied over the dressing can generate substantial out-of-plane forces on the contact layer fabric.
Spunlace nonwoven for medical use is produced in two surface structure configurations that differ fundamentally in their fluid management behavior and their interaction with the wound surface.
Plain surface fabric presents a smooth, uniform, closed-structure contact face. There are no deliberate apertures in the fabric plane. This structure delivers uniform contact pressure distribution across the wound surface, minimizing mechanical stress at the wound margin and the granulation tissue surface. It provides the most consistent liquid uptake across the fabric area — every zone of the fabric participates equally in exudate absorption. Plain fabric is the standard specification for primary wound contact layers on clean surgical wounds, traumatic wounds in the proliferative healing phase, and transdermal drug delivery substrates where uniform drug distribution across the contact surface is required.
Mesh fabric features a regular pattern of through-plane apertures created by the spatial geometry of the hydroentanglement water jets during manufacturing. The apertures serve two distinct clinical functions. First, they create defined fluid drainage channels: rather than absorbing exudate uniformly across the fabric plane, a mesh structure allows exudate to pass through the apertures by capillary pressure differential and drain into an underlying secondary absorbent layer. This reduces fluid retention at the wound surface, which is clinically desirable in moderate-to-high exudate wounds where maceration of periwound skin is a risk. Second, the open mesh structure promotes gas exchange through the dressing, supporting aerobic wound management and reducing the risk of anaerobic bacterial proliferation beneath an occluded wound surface.
Mesh fabric also has a functional role in non-adherence. The reduced contact area between a mesh fabric and the wound surface — compared to a plain fabric of equivalent basis weight — lowers the adhesion force between the fabric and newly forming epithelium or granulation tissue. This makes mesh-structured wound contact layers particularly useful in wounds with fragile granulation tissue or newly formed epithelium, where adherence during dressing removal is a specific clinical concern.
Both plain and mesh structures are available in Aojia's wound dressing substrate range.
Any textile material used as a wound contact layer in a sterile medical device must demonstrate stable performance after exposure to the industrial sterilization process applied by the finished device manufacturer. The three primary sterilization routes applicable to wound dressing products are ethylene oxide (EtO) gas, gamma irradiation, and electron beam (E-beam) processing.
Ethylene oxide sterilization uses a reactive alkylating gas at controlled temperature, humidity, and concentration to achieve a sterility assurance level (SAL) of 10⁻⁶. EtO is the most widely used sterilization method for wound dressing products because it is effective across a wide range of packaging materials and device geometries, and it does not generate the high-energy radiation that can degrade certain polymer systems. The critical fabric validation requirement for EtO is aeration: EtO and its reaction byproducts (ethylene chlorohydrin and ethylene glycol) must be shown to degas to below established residual limits before the product is released. For spunlace fabrics, aeration profile testing must be performed on the fully packaged product configuration at the intended sterilization dose.
Gamma irradiation sterilization uses high-energy photons from a cobalt-60 source or a linear accelerator to damage bacterial DNA. Standard sterilization doses for wound dressings range from 15 to 25 kGy, with dose validation performed under ISO 11137. Gamma irradiation is compatible with the viscose/polyester spunlace structure — neither cellulosic nor polyester fibers exhibit significant mechanical degradation at standard wound dressing sterilization doses. However, any antibacterial chemical treatment applied to the fabric must independently demonstrate stability through the intended gamma dose range, because ionizing radiation can degrade certain organic biocide molecules.
Electron beam sterilization offers a higher dose rate than gamma, a smaller footprint, and the ability to be turned off between sterilization cycles — advantages from a manufacturing process control perspective. E-beam penetration depth is more limited than gamma, which means package geometry and product density must be validated carefully to ensure dose uniformity throughout the product. For spunlace wound dressing substrates, E-beam compatibility validation follows the same general framework as gamma: mechanical property retention testing before and after irradiation at the maximum intended sterilization dose.
Compatibility documentation for all three sterilization methods should be requested from a substrate supplier and reviewed as part of the design input process for a new wound dressing product.
Wound dressings incorporating antibacterial spunlace nonwoven are regulated as medical devices in all major markets, and the regulatory documentation requirements for the fabric substrate feed directly into the device manufacturer's technical file.
In the European Union, wound dressings are classified under EU MDR 2017/745. Most primary wound contact layers are Class I or Class IIa devices; the classification escalates to Class IIb or III when the dressing incorporates a drug substance (including silver in quantities intended to have a pharmacological effect) that is ancillary to the primary mode of action. EN 13726 provides the harmonized test methods for primary wound dressings, covering fluid handling (absorption capacity, moisture vapor transmission rate) and physical integrity under clinical conditions. EN 14079 specifically addresses absorbent dressings of nonwoven fabric. Compliance with these standards, combined with ISO 10993 biocompatibility testing and a conformity assessment through a notified body (for Class IIa and above), forms the core of the CE marking pathway.
ISO 10993 biocompatibility testing is organized across multiple parts. For a wound contact layer, the minimum required evaluations typically include ISO 10993-5 (cytotoxicity), ISO 10993-10 (sensitization), ISO 10993-23 (skin irritation), and ISO 10993-12 (sample preparation for biological evaluation). For antibacterially treated fabrics, additional evaluations covering systemic toxicity and genotoxicity may be required depending on the nature and concentration of the antibacterial agent. The binder-free structure of spunlace nonwoven simplifies the extractables and leachables profile relative to chemically bonded alternatives, but the testing scope must still be determined by a risk-based evaluation of the material's constituent chemicals.
In the United States, wound dressings are regulated by the FDA under 21 CFR Part 880. Most primary wound contact layers are Class II devices subject to 510(k) premarket notification. The 510(k) submission requires substantial equivalence demonstration against a legally marketed predicate device, including biocompatibility, performance testing, and sterility validation data.
Industrial wound dressing converting operations work with fabric rolls from a substrate supplier and process them through slitting, die-cutting, lamination, folding, and packaging lines to produce finished dressing units. The width specification of the substrate roll — and the precision of that width — directly impacts converter yield, material waste, and line changeover frequency.
Aojia's wound dressing substrate is available in widths from 100 mm to 3,200 mm. This range is exceptionally broad and covers the full spectrum of converter requirements. Narrow widths from 100 mm to approximately 300 mm serve converting lines that process small island dressings, adhesive bandage contact layers, and specialty wound care formats where a pre-slit narrow roll feeds directly into a high-speed converting machine without further slitting. Medium widths in the 600–1,600 mm range serve standard converting lines that produce roll-based absorbent dressings and multi-layer wound care products. Wide widths approaching 3,200 mm are appropriate for converting operations with high-throughput slitting equipment that maximizes material utilization by processing a single wide mother roll into multiple parallel slit lanes simultaneously.
Roll length, core diameter, and maximum roll outer diameter are the secondary roll specification parameters that determine compatibility with converter winding equipment and storage logistics. Custom roll specifications can be arranged through Aojia's Contact Us channel for high-volume converting partners.
The selection of a fabric substrate supplier for a medical device product is a supplier qualification decision, not merely a purchasing decision. The fabric supplier becomes a component of the device manufacturer's quality management system, and their manufacturing processes, documentation practices, and change control procedures directly affect the device manufacturer's regulatory compliance.
The first evaluation criterion is manufacturing process documentation. A qualified medical nonwoven substrate supplier maintains detailed process control records for every production batch, including fiber lot traceability, hydroentanglement parameter records, GSM verification data, tensile strength test results, and any functional finishing application records. This documentation forms the basis of the certificate of conformance that accompanies each shipment and feeds into the device manufacturer's incoming inspection and batch release records.
The second criterion is test capability. The supplier should be able to provide — or reference accredited third-party test data for — the key fabric physical parameters: basis weight (per EDANA 40.3-90 or equivalent), tensile strength dry and wet (per EDANA 20.2-89 or equivalent), elongation, and lint generation. For antibacterially treated fabrics, test data demonstrating antibacterial efficacy and stability of the treatment through the claimed shelf life should be available.
The third criterion is biocompatibility documentation. For a wound contact layer substrate, the supplier should provide material safety data, fiber constituent information, and preferably ISO 10993-compliant cytotoxicity and irritation test data that can support the device manufacturer's own biocompatibility evaluation. A supplier who cannot provide this documentation shifts the entire biocompatibility testing burden to the device manufacturer.
The fourth criterion is custom development capability. Wound dressing product development rarely uses only standard catalog specifications. The ability to modify fiber blend ratio, basis weight, surface structure, or functional finishing — and to support this development with adequate technical engagement and sample production — determines how quickly a new product can move from concept to validated design input specification.
Zhejiang Aojia Nonwoven Technology Co., Ltd. operates two dedicated spunlace production lines: one optimized for consistent commercial-scale production and one dedicated to new product R&D and specialty development. This dual-line structure provides the infrastructure to support custom development alongside commercial supply without the technical compromises that single-line suppliers face when attempting to run both functions simultaneously. The company's certifications and quality credentials are available for review on the About Us page.
Zhejiang Aojia Nonwoven Technology Co., Ltd. produces its wound dressing spunlace substrate fabric within the Medical Series product line, alongside the face mask cloth product for respiratory protection applications. Both products share the same hydroentanglement manufacturing platform and the same quality infrastructure.
The wound dressing substrate is available in:
Fiber composition: 70% viscose / 30% polyester (standard); custom blends on request Basis weight: 40–60 g/m² standard; custom GSM available Width: 100 mm to 3,200 mm Surface structure: plain and mesh Antibacterial treatment: available as functional finishing; treatment chemistry by converter or Aojia recommendation Sterilization compatibility: EtO, gamma irradiation, and E-beam validated
Wound dressing developers, converters, and medical device manufacturers with requirements outside the standard specification range, or with questions about custom development, regulatory documentation support, or sample evaluation, are encouraged to reach the Aojia technical and commercial team through the Contact Us page.
The complete Medical Series product range, along with Aojia's broader product portfolio covering Wipes Series, Cosmetology Series, Base Cloth Series, and Wiping Cloth Series, is available for review at spunlacenon-wovenfabric.com.
