Dynamic Mechanical Analysis (DMA)

Hydrogels possess a unique ability to mimic the extracellular matrix (ECM), making them indispensable in tissue engineering, wound management, and drug delivery. However, characterizing these soft, viscoelastic networks is challenging; they behave as complex hybrids of solids and fluids. Matexcel offers specialized Dynamic Mechanical Analysis (DMA) services designed to rigorously quantify these properties. By providing high-resolution data on viscoelastic behavior, we empower researchers to optimize crosslinking densities, predict in vivo performance, and accelerate the clinical translation of biomaterials.

Service Overview

Matexcel's DMA service provides a comprehensive mechanical profile by applying oscillatory deformation under controlled conditions. Unlike static testing, our approach decouples the material's response into elastic (energy storing) and viscous (energy dissipating) components. This analysis is critical for predicting performance under physiological loads, such as the cyclic compression of cartilage or shear forces during injection.

Technical Principles

Our analysis resolves the hydrogel's response to sinusoidal stress into three critical parameters:

• Storage Modulus (G' or E'): Represents the elastic energy stored per cycle. It is a direct indicator of stiffness and crosslinking density.
• Loss Modulus (G'' or E''): Represents the energy dissipated as heat, reflecting the material's viscous, liquid-like character.
• Loss Factor: The ratio G''/G'. A tanδ <1 indicates a dominant elastic structure (gel state), while tanδ >1 indicates liquid-like behavior (sol state), which is vital for assessing stability.

Technical Features

Our facility addresses the delicate nature of hydrogels with:

• High-Sensitivity Force Control: Capable of applying forces as low as 0.0001 N to characterize ultra-soft gels without damage.
• Physiological Simulation: We utilize fluid-immersion clamps to test samples submerged in PBS or saline at 37°C, preventing dehydration and ensuring biological relevance.
• Broad Frequency Range: Instrumentation spans 0.01 to 200 Hz to cover diverse biological timescales.

Technical Classifications

Matexcel employs specific testing modes to isolate distinct material behaviors:

• Strain Sweep: This mode is used to determine the Linear Viscoelastic Region (LVR). It identifies the critical strain limit where the hydrogel structure begins to break down, ensuring that subsequent tests are performed non-destructively within the material's stable range.
• Frequency Sweep: By measuring G' and G'' across varying frequencies, this test simulates the material's response to different timescales of loading. It effectively distinguishes between rapid impact stability and slow deformation compliance.
• Time Sweep: This analysis monitors moduli over a set duration to observe time-dependent behaviors. It is critical for characterizing gelation kinetics (curing) or assessing degradation profiles under constant environmental conditions.

• Temperature Ramp: This mode varies the temperature at a constant frequency to characterize thermal sensitivity. It is essential for detecting phase transitions, such as the Lower Critical Solution Temperature (LCST) in thermo-responsive hydrogels.

Application Fields

• Tissue Engineering: Matching scaffold viscoelasticity to native tissue is crucial for guiding stem cell differentiation.
• Wound Dressings: Tuning damping capacity ensures dressings conform to movement while maintaining structural integrity.
• Drug Delivery: Correlating mesh size with modulus data allows for the precise engineering of release profiles.

Our Services

Matexcel provides targeted characterization packages tailored to product development:

• Physiological Simulation Testing: Standard air testing alters hydrogel properties via dehydration. We offer submersible DMA testing where samples are immersed in physiological media at 37°C. This ensures measured moduli reflect the in vivo state, accounting for osmotic swelling and ionic interactions.
• Gelation Kinetics and Curing Analysis: For in situ forming implants, understanding the sol-gel transition is critical. Our time-sweep analysis monitors the evolution of G' and G'' in real-time. We identify the "gel point" (crossover where G' = G'') and time-to-peak stiffness, aiding in the optimization of surgical handling windows.
• Fatigue and Durability Profiling: Implants like cartilage replacements undergo millions of cycles. We perform dynamic fatigue testing, subjecting hydrogels to prolonged cyclic loading to evaluate hysteresis and long-term structural failure. This data is essential for predicting service life under repetitive stress.
• Stress Relaxation and Creep Recovery: To evaluate response to sustained loads, we perform stress relaxation (stress decay at constant strain) and creep recovery (deformation under constant load) tests. These characterize viscoelastic relaxation times, critical for predicting how scaffolds remodel and integrate with host tissues.
• Injectability and Self-Healing Characterization: For minimally invasive therapies, we assess injectability by analyzing shear-thinning behavior and self-healing via recovery tests. We quantify the reduction in viscosity under high shear (injection) and the speed at which G' recovers post-injection, ensuring the material can be delivered through a needle and immediately regain function.

Company Service Advantages

• Custom Fixture Design: We utilize specialized geometries, including parallel plates for bulk gels and tension clamps for fibers, ensuring accurate data regardless of sample shape.
• Standards Compliance: Protocols align with ASTM D5024 (compression) and ASTM F2150 (biomaterial scaffolds) to support regulatory data requirements.
• Expert Interpretation: Matexcel provides actionable insights, translating raw viscoelastic data into guidance for molecular structure optimization.

Contact us

Dynamic mechanical analysis is the definitive tool for decoding the mechanical reality of hydrogels. Matexcel bridges the gap between synthesis and application by providing rigorous, physiologically relevant data. Leverage our advanced instrumentation to engineer hydrogels that meet the demanding requirements of modern medicine.

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