Photo-Crosslinking and Patterning of PEG-Based Hydrogels (2D/3D): Principles, Method Comparisons, and Product Selection Guidelines
Photo-Crosslinking and Patterning of PEG-Based Hydrogels (2D/3D): Principles, Method Comparisons, and Product Selection Guidelines
Why Is Hydrogel “Patterning” Needed?
Biomaterial scaffolds commonly used in tissue engineering and cell biology research are often homogeneous: they have uniform composition, uniform stiffness, and uniformly distributed signaling molecules. In real tissues, however, the cellular microenvironment is highly organized:
1. Mechanical properties (e.g., stiffness, softness, viscoelasticity) vary across different regions;
2. Biochemical cues presented at different locations (adhesive ligands, growth factors, enzyme-cleavable sites, etc.) are not the same;
3. These signals also change over time (for example, during wound healing, development, or tumor invasion).
Therefore, to study how material properties influence cell behavior across spatial and temporal dimensions—including migration, differentiation, morphology, gene expression, and tissue formation—it is necessary to achieve spatially and temporally controllable “patterning” within hydrogels.
Importantly, many studies aim to perform localized modification after cells have already been encapsulated or have begun to grow within the material. This places strict requirements on the patterning process: it must be as gentle as possible—without significantly reducing cell viability, without introducing toxic residues that are difficult to remove, and without excessively disrupting the original network structure.
Why Are PEG Hydrogels Commonly Chosen as “Patterning Substrates”?
Poly(ethylene glycol) (PEG)–based hydrogels are widely used in tissue engineering, mainly for the following three reasons:
1. Favorable baseline biocompatibility
PEG has a long history of use in various biomedical and pharmaceutical systems. It is generally regarded as having good overall biocompatibility; however, this does not mean that all forms of PEG, in all application scenarios, are “absolutely safe” or “completely free of immunological risk.” Indeed, immune responses to PEG (such as the formation of anti-PEG antibodies) have been reported in certain cases involving long-term or repeated exposure, or specific formulations.
2. Tunable mechanical properties
By adjusting parameters such as PEG molecular weight, functionality, crosslinking density, and the incorporation of degradable segments, PEG hydrogels can span a broad mechanical range relevant to soft tissues. This makes them suitable for studies involving stiffness gradients, localized stiffening, or localized softening.
3. “Blank slate” characteristics
PEG networks typically exhibit low levels of nonspecific protein adsorption and weak intrinsic cell adhesion. Paradoxically, this is an advantage: PEG can serve as a substrate with minimal biological background noise, onto which adhesive peptides, degradable motifs, or growth-factor-binding sites can be introduced at defined locations as needed. This allows experimental observations to be interpreted more clearly and mechanistically.
How PEG Hydrogels Form: Fundamental Concepts of Photo-Crosslinking (and Common Misconceptions)
The most common class of PEG hydrogels is derived from PEG macromers bearing crosslinkable functional groups (such as PEG diacrylate, PEGDA, or PEG methacrylate). During preparation, a photoinitiator is typically added to an aqueous solution, and UV or visible light irradiation is used to trigger free-radical reactions, leading to network crosslinking and gel formation.
Several key points need to be clearly addressed:
1. Photoinitiators must be “aqueous-compatible / cell-friendly”
When cells are encapsulated or present during gelation, research more commonly employs photoinitiation systems that can operate in aqueous environments and are relatively mild (for example, certain UV photoinitiators usable in water, or visible-light systems such as LAP).
2. Trade-offs between curing speed and cell viability
Faster curing often implies higher light doses or more intense free-radical reactions, which can increase the risk of phototoxicity and oxidative stress. In cell-based experiments, it is usually necessary to balance gelation efficiency, patterning resolution, and cell viability.
3. Oxygen inhibition is not “the stronger, the better”
Oxygen can terminate free-radical reactions, affecting curing depth, surface gelation, and boundary definition. Pattern clarity arises from the coupling of multiple factors (light field distribution, reaction kinetics, radical lifetime and diffusion, precursor diffusion, oxygen inhibition, etc.). It is therefore inaccurate to simply state that “oxygen inhibition guarantees high fidelity.” More precisely, oxygen inhibition significantly influences pattern quality and curing behavior and must be controlled or compensated for. In general, oxygen inhibition reduces conversion and curing depth.
Two Routes: First “Build Complex Geometry,” or “Modify an Existing Hydrogel”
PEG hydrogel patterning can broadly be divided into two categories:
1. Route A: Direct fabrication of complex geometrical networks
Examples include mold-based fabrication, microfluidic molding, photolithographic patterning, and 3D bioprinting. The goal is to endow the hydrogel itself with complex shapes or channel structures.
2. Route B: “Secondary patterning modification” of pre-formed hydrogels
In this approach, the hydrogel is formed first (often with cells already encapsulated), and light-triggered reactions are then used to locally graft specific molecules into the network or locally alter crosslinking density and/or degradability, thereby creating spatial heterogeneity.
Definitions Used in This Article
(1) 2D patterning: Patterns vary in the x–y plane but are essentially uniform along the z direction (“vertically homogeneous”).
(2) 3D patterning: Patterns can vary along the x, y, and z directions (true three-dimensional spatial distributions within the bulk).
Method | Typical Pattern Dimensionality | Principle | What It Can Do | Advantages | Limitations / Risk Points | Who It Suits / When to Use |
Photomask (transparent film / photomask plate) | 2D (surface or near-surface; simplified “through-thickness” channels can be made) | Uses a mask to restrict illuminated regions, enabling localized grafting or curing | Cell islands, stripes, channels; simple multiple grafting steps | Low cost, easy to implement, suitable for large areas | Resolution limited by mask contact, scattering, and diffusion; repeated illumination may harm cells; residual monomers require thorough washing | Entry-level use, teaching, rapid validation, applications requiring large-area regular patterns |
Confocal “virtual mask” scanning | Primarily 2D, with limited 3D layering | Controls exposure via scanning paths and laser power, enabling “drawing-like” grafting | Custom shapes, concentration gradients, multi-component patterns | No physical mask required; easy to create complex curves and gradients; fast design iteration | Slow for large areas; moderate equipment barrier; limited deep-volume control | Research and development requiring gradients or complex patterns with frequent design changes |
Two-photon (Two-photon excitation) | 3D | Reactions occur only at the focal point, enabling true 3D “writing” inside the gel | Internal 3D channels, lattices, spatially partitioned signals within hydrogels | True 3D precise localization; strong selectivity along the z-axis | Expensive equipment; complex parameter space; slow writing speed; light dose must still be carefully controlled. Many systems require suitable photosensitive groups or sensitization strategies—otherwise efficiency may be limited. | Studies of three-dimensional microenvironments, invasion/migration, and spatial compartmentalization mechanisms |
Method Selection – Quick Reference Table
Your Requirement / Constraint | Recommended Primary Method | Explanation |
Only surface patterns needed (cell islands/stripes) and speed/low cost is important | Photomask | Most cost-effective; well suited for large-area regular patterns |
Frequent pattern changes or complex curves/gradients required | Confocal scanning | “Drawing-style exposure” makes gradient control and design iteration easier |
True 3D internal structures or spatially partitioned signals within hydrogels | Two-photon | In-volume writing with the best control along the z-axis |
Cells present and highly sensitive to viability | Gentler wavelengths / low-dose systems + (mask / confocal / two-photon chosen by goal) | The key is not “which instrument,” but rather “light dose and initiation chemistry” |
Need signals that can be “added + removed,” or decoupling of mechanical and biochemical cues | Orthogonal chemistry / photocleavable strategies | Not a replacement for the above methods, but a way to enhance controllability |
Key Factors Affecting Pattern Quality and Cell Viability
Factor | What It Affects | Typical Manifestations | Optimization Directions |
Light penetration / scattering (gel thickness, turbidity) | Pattern depth, boundary sharpness | Blurred boundaries in thick gels; weak modification in deeper regions | Reduce thickness, improve transparency, adjust wavelength/light intensity; for true 3D needs, consider two-photon approaches |
Precursor diffusion (functional molecule size / time) | Boundary sharpness, gradient formation | Diffusion before illumination leads to “broadening” or penetration | Control diffusion time and concentration; minimize diffusion when sharp edges are required |
Radical lifetime and diffusion | Resolution, localized curing | “Halo” or spreading at pattern edges | Control exposure and initiation system; avoid excessive exposure |
Oxygen inhibition | Curing depth / surface reactions | Poor surface curing or unintended gradients | Control oxygen environment and exposure conditions; do not treat oxygen inhibition as a one-way advantage |
Light dose and initiation system | Cell viability, curing efficiency | Phototoxicity, oxidative stress, reduced viability | Choose gentler wavelengths and initiators; lower dose and extend or segment exposure (system-dependent) |
Residual monomers / initiators | Cytotoxicity, reproducibility | Inadequate washing leads to poor subsequent cell states | Strengthen rinsing/exchange steps; minimize reliance on “incomplete polymerization to retain reactive groups” |
Product Selection Guide Table
Application Scenario | Recommended Priority Category | Key Selection Considerations | Typical Function / What You Obtain |
Preparing PEG-based hydrogels (basic gel formation) | Photo-crosslinkable macromers (PEGDA / PEGDMA) | First choose the end group: acrylate PEGDA reacts faster; PEGDMA typically polymerizes more slowly and is more sensitive to process parameters. In cell systems, “friendliness” depends on the final required light dose and radical burden. Then choose molecular weight: higher Mn is generally softer with larger mesh size; lower Mn is denser and stiffer. | Formation of a “blank slate” gel suitable for subsequent cell encapsulation, surface/internal functionalization, and patterning |
Thin coatings / high crosslink density / high-resolution patterns | Photo-crosslinkable macromers (low Mn PEGDA) | Low Mn (e.g., Mn ~200) yields denser networks and sharper boundaries, but may be too stiff or diffusion-limited for 3D cell environments | Harder, denser networks better suited for thin layers, structural stability, and micro-patterns |
Softer 3D cell environments (migration / invasion / diffusion) | Photo-crosslinkable macromers (high Mn PEGDA / PEGDMA) | High Mn (e.g., Mn ~10,000) is usually softer with larger mesh size; favorable for cell migration and nutrient diffusion (mechanics still tuned via concentration and formulation) | Scaffolds closer to soft tissue microenvironments, supporting cell viability, migration, and long-term culture |
2D surface patterning (cell islands / stripes / channels) | Photo-crosslinkable macromers + photoinitiator + adhesive peptides | Common route: form the gel first, then photo-graft adhesive peptides at defined locations; exposure dose must be balanced against cell viability | Site-specific adhesion on PEG’s low-adhesion background, enabling control of cell morphology, migration paths, and co-culture boundaries |
2D concentration gradients / complex curved patterns (greater flexibility) | Photoinitiator (cell-friendly prioritized) + photo-crosslinkable macromers | When fine exposure control is required, initiator stability and reproducibility are critical. I2959 can be used in hydrogels but has limited solubility in pure water/buffers and often requires small amounts of organic solvent for stock preparation or assisted dissolution. For higher water solubility and longer-wavelength irradiation, LAP and related systems may be considered. | Enables ligand concentration gradients and multi-step superimposed patterns for threshold-response, chemotaxis, and adhesion-gradient studies |
3D in-volume patterning (two-photon / deep writing) | Photoinitiation system (chosen by equipment and chemistry) + photo-crosslinkable macromers | 3D writing emphasizes localized reactions and low phototoxicity. I2959 or LAP can be used for initial validation; material-oriented initiators (e.g., 369/TPO) are more typical for non-biological systems and require caution when cells are present | Creation of internal channels, lattices, and spatially partitioned signals for 3D migration, invasion, and compartmentalization studies |
Need for “orthogonal chemistry”: gel formation without radicals, followed by secondary photo-functionalization (decoupling mechanics and biochemistry) | PEGDGE (epoxy) / carboxylated PEG + coupling reagents | Epoxy end groups enable ring-opening crosslinking; carboxyl groups can couple to amines via EDC/NHS. Suitable for “stable network + controllable functionalization” designs | Separation of network formation and functionalization, reducing interference from patterning steps and improving controllability and reproducibility |
Need for “removable signals / photodegradation” | Photocleavable groups / precursors | o-Nitrobenzyl-type groups are commonly used to create cleavable linkers or crosslink points, enabling time-controlled signal removal | Dynamic microenvironment studies involving “signal addition → removal → re-addition” |
Thiol–norbornene orthogonal click networks (cleaner networks and functionalization) | Norbornene groups + dithiol crosslinkers (examples) | Representative orthogonal chemistry route: norbornene end groups crosslinked with dithiols; DTT can serve as an example crosslinker/reductant (practical systems often use PEG-dithiols) | Click-type networks with easier mechanical–biochemical decoupling, low shrinkage, and fewer side reactions (suitable for advanced studies and method development) |
Concern: why is curing slow or patterns unclear? | Inhibitors / stabilizers (diagnostic item) | Many PEGDA/PEGDMA products contain MEHQ/BHT, which inhibit polymerization. This is not “bad,” but process compensation is required (removal of inhibitors, increased initiator or exposure, longer curing time, etc.). | Helps diagnose curing failures and improve gelation and patterning success |
Exploring visible-light photosensitization / dyes or photocatalytic schemes | Photosensitizers / dyes (optional) | More relevant to method development and visualization; applicability depends on system chemistry and cell sensitivity | Used for visible-light system exploration, staining, or sensitization strategies (not essential to the main workflow, but extendable) |
Only basic PEG needed (solutions / spacers / formulation additives), no direct crosslinking | Base polymer PEG | PEG itself does not crosslink unless end-modified; used for formulation tuning, osmotic control, hydrophilic spacers, etc. | Base material or additive, or precursor for subsequent functionalization |
Need enzymatic degradation / tissue digestion / validation of degradable models | Collagenase (different grades) | Selection depends on use: cell culture favors sterile, consistent grades; compliance/production favors GMP; strong digestion favors high-activity, broad-spectrum enzymes | Collagenase is suitable for networks containing collagen/gelatin or collagenase-sensitive peptide motifs. For MMP-sensitive designs, validation should rely on MMPs or relevant cell-secreted enzyme systems. |
PEG-Based Hydrogel Photo-Crosslinking and Patterning (2D/3D): Supporting Reagents — Aladdin Representative Product List and Selection Guide
The following table lists representative Aladdin products relevant to PEG-based hydrogel photo-crosslinking and patterning. For additional specifications and products, please refer to the full product list at the end of this document or search the Aladdin website using the CAS number or product name.
Category | CAS No. | Aladdin Cat. No. | Product Name | Specification / Purity | Product Description / Role |
Photo-crosslinkable macromer (acrylate) | 26570-48-9 | Poly(ethylene glycol) diacrylate (PEGDA) | Avg. Mn 2000, contains ≤1500 ppm MEHQ as inhibitor | PEGDA (Mn ~2000); core gelation and patterning substrate discussed in this article; contains MEHQ stabilizer—photo-curing requires optimization of exposure, initiator, or inhibitor removal | |
Photo-crosslinkable macromer (acrylate) | 26570-48-9 | Poly(ethylene glycol) diacrylate (PEGDA) | Avg. Mn 10000, contains MEHQ as inhibitor | PEGDA (Mn ~10000); softer tendency with larger mesh size; suitable for 3D cell environments and migration studies (mechanics must be tuned via formulation) | |
Photo-crosslinkable macromer (acrylate) | 26570-48-9 | Poly(ethylene glycol) diacrylate (PEGDA) | Avg. Mn ~200, contains MEHQ stabilizer | PEGDA (Mn ~200); high crosslink density, relatively stiff; suitable for thin layers, coatings, rapid curing, or high-resolution patterning (cell encapsulation requires careful evaluation of stiffness and diffusion) | |
Photo-crosslinkable macromer (methacrylate) | 25852-47-5 | α,ω-Dimethacrylate poly(ethylene glycol) | Avg. Mn 2000, ~1000 ppm MeHQ as stabilizer | PEGDMA (Mn ~2000); radical photo-crosslinkable for gelation and patterning grafting; MEHQ inhibitor requires process compensation or removal | |
Photo-crosslinkable macromer (methacrylate) | 25852-47-5 | Poly(ethylene glycol) dimethacrylate | Avg. Mn 10000, contains MEHQ as inhibitor | PEGDMA (Mn ~10000); photo-crosslinkable for gelation and patterning; methacrylates are generally slower/milder in reactivity, requiring optimized initiator and exposure parameters | |
Photo-crosslinkable macromer (acrylate, extended systems) | P477925 | PEG–PPG–PEG diacrylate (triblock) | Avg. Mw ~15 kDa | Triblock diacrylate; photo-crosslinkable for gelation and patterning; hydrophobic PPG segments enable extended studies of mechanics, phase behavior, and thermoresponsive hydrogels | |
Photoinitiator (cell-/aqueous-compatible, UV) | 106797-53-9 | 2-Hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone | ≥98% (HPLC) | Irgacure 2959 (I2959); commonly used for PEGDA/PEGDMA aqueous photo-gelation and patterning grafting; relatively cell-friendly | |
Photoinitiator (cell-/aqueous-compatible, UV) | 106797-53-9 | I2959 | Moligand™, 10 mM in DMSO | I2959 solution; convenient for cell-related PEG photo-crosslinking and patterning with standardized preparation | |
Photoinitiator (visible light, aqueous) | 85073-19-4 | LAP | Moligand™, 10 mM in DMSO | Representative visible-light initiator system; used for PEG photo-gelation and patterning under milder wavelengths (generally more cell-friendly) | |
Photoinitiator (visible light, aqueous) | 85073-19-4 | Lithium phenyl(2,4,6-trimethylbenzoyl)phosphinate (LAP) | ≥98% | High-purity LAP; widely used for visible-light crosslinking and patterning of PEG hydrogels, especially in the presence of cells | |
Bioactive ligand (cell-adhesive peptide) | 91037-65-9 | Arg–Gly–Asp–Ser | Moligand™, 10 mM in water | RGDS peptide solution; introduces cell-adhesive sites on PEG hydrogel surfaces or interiors (requires graftable chemistry such as acrylation or thiolation) | |
Bioactive ligand (cell-adhesive peptide) | 91037-65-9 | Arg–Gly–Asp–Ser | ≥95% (HPLC) | High-purity RGDS solid; used to introduce adhesion signals on PEG “blank slate” substrates after reactive end-group modification and grafting/patterning | |
Photoinitiator (radical, UV) | 24650-42-8 | 2,2-Dimethoxy-2-phenylacetophenone | ≥99% | Radical photoinitiator for acrylate polymerization/curing; more typical for material systems—solubility and cytotoxicity must be evaluated in cell contexts | |
Photoinitiator (radical, UV) | 119313-12-1 | 2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one | ≥98% (HPLC) | Irgacure 369; highly efficient radical initiator for curing/patterning; requires careful phototoxicity and residue assessment when cells are present | |
Photoinitiator (radical, UV) | 119313-12-1 | 2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one | ≥95% | Same as above; used for acrylate/methacrylate photo-polymerization and patterning | |
Photoinitiator (radical, UV) | 119313-12-1 | Photoresist initiator | — | Same CAS as Irgacure 369; primarily for photolithography/material curing applications | |
Photoinitiator (radical, UV/visible, materials) | 75980-60-8 | Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) | ≥97% | High-efficiency photoinitiator for material/resin curing; cell applications require cautious selection and thorough evaluation | |
Orthogonal chemistry / chemical crosslinking precursor (epoxy PEG) | 72207-80-8 | Poly(ethylene glycol) diglycidyl ether | Mn 2000 | PEGDGE (Mn ~2000); used for epoxy ring-opening crosslinking and orthogonal strategies; candidate for non-radical gel formation | |
Orthogonal chemistry / chemical crosslinking precursor (epoxy PEG) | 72207-80-8 | Poly(ethylene glycol) diglycidyl ether (PEGDGE) | Mn 500 | PEGDGE (Mn ~500); denser and more reactive; used for epoxy crosslinking or as a functionalization intermediate (cell systems require strict evaluation and purification) | |
Orthogonal chemistry / chemical crosslinking precursor (epoxy PEG) | 39443-66-8 | Poly(ethylene glycol) diglycidyl ether | Epoxy value 0.70–0.80 mol/100 g; viscosity (25 °C): 5–25 mPa·s | Epoxy-terminated PEGDGE; reacts with amines/thiols for network formation; suitable for “non-radical gelation + secondary photo-functionalization” strategies | |
Orthogonal chemistry / chemical crosslinking precursor (epoxy PEG) | 4206-61-5 | Poly(ethylene glycol) diglycidyl ether | Epoxy value 0.63–0.68 eq/100 g | PEGDGE class material; used for epoxy crosslinking and orthogonal chemistry to decouple network formation from subsequent functionalization | |
Orthogonal chemistry monomer (thiol–norbornene) | 498-66-8 | Norbornene | ≥99% | Parent norbornene moiety; used to synthesize PEG-NB/PEG-Nor systems for thiol–norbornene orthogonal photo-click chemistry | |
Reducing agent / dithiol crosslinker (orthogonal chemistry) | 3483-12-3 | DL-Dithiothreitol (DTT) | Molecular biology grade, ≥99% | Common reducing agent and representative dithiol crosslinker for thiol–ene/thiol–norbornene systems | |
Reducing agent / dithiol crosslinker (orthogonal chemistry) | 3483-12-3 | DL-Dithiothreitol (DTT) | For electrophoresis, ≥99% | Same as above; different application grade | |
Carboxyl coupling / activation reagent (EDC system) | 25952-53-8 | 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride | ≥98% | Classic water-soluble carbodiimide for carboxyl–amine coupling (used with NHS) to covalently link PEG–carboxyls with peptides/proteins for functionalization or orthogonal modification | |
Carboxyl coupling / activation reagent (EDC system) | 25952-53-8 | Premium-Grade EDC | — | Higher-grade EDC for coupling and biofunctionalization applications sensitive to purity and impurities | |
Carboxyl coupling / activation reagent (EDC system) | 25952-53-8 | Aladdin™ EDC | Analytical standard | EDC analytical standard for method validation and quality control (same coupling chemistry as EDC·HCl) | |
Carboxyl coupling / activation reagent (NHS) | 6066-82-6 | N-Hydroxysuccinimide (NHS) | ≥98% | Used with EDC to form NHS esters, improving carboxyl–amine coupling efficiency; applied to PEG dicarboxyl–peptide/protein conjugation and functional network construction | |
Functional PEG precursor (carboxyl-terminated) | 39927-08-7 | Poly(ethylene glycol) dicarboxylic acid | Avg. Mn 600 | PEG dicarboxylic acid; used via EDC/NHS coupling to prepare PEG–peptide/PEG–protein conjugates and linkers for orthogonal/functionalizable strategies | |
Functional PEG precursor (carboxyl-terminated) | 39927-08-7 | Poly(ethylene glycol) bis(carboxymethyl) ether | Avg. Mn 250 | Carboxyl-terminated PEG derivative; used for coupling, linker construction, reactive site introduction, or hydrophilic spacers | |
Photocleavable group / precursor (o-nitrobenzyl) | 612-25-9 | 2-Nitrobenzyl alcohol | ≥98% (GC) | Representative o-nitrobenzyl photocleavable group; used to synthesize removable-signal or photodegradable linkers/crosslinkers | |
Enzyme (degradation / model construction) | 9001-12-1 | Collagenase from Clostridium histolyticum (non-animal origin, A) | EnzymoPure™, ≥150 units/mg dry weight | Collagenase for degradable models, cell release, and tissue digestion; used to validate degradation and migration channels in collagenase-sensitive hydrogels | |
Enzyme (degradation / model construction) | 9001-12-1 | Collagenase AF-1 from Clostridium histolyticum | EnzymoPure™, ≥3.00 U/mg | Alternative collagenase grade for tissue digestion and degradation studies | |
Enzyme (degradation / model construction) | 9001-12-1 | Collagenase NB 4 from Clostridium histolyticum | EnzymoPure™, standard grade, ≥0.10 U/mg | NB-series collagenase for digestion, degradation, or standard applications | |
Enzyme (degradation / model construction) | 9001-12-1 | Collagenase NB 4G from Clostridium histolyticum | EnzymoPure™, certified grade, ≥0.18 U/mg (PZ activity per Wünsch, 25 °C) | Higher-grade collagenase with defined activity standards; suitable for applications requiring higher consistency | |
Enzyme (degradation / model construction) | 9001-12-1 | Collagenase NB 5 from Clostridium histolyticum | EnzymoPure™, sterile, ≥0.10 U/mg | Sterile version; suitable for cell culture–related degradation/digestion | |
Enzyme (degradation / model construction) | 9001-12-1 | Collagenase NB 6 from Clostridium histolyticum | EnzymoPure™, GMP, ≥0.100 U/mg | GMP-grade enzyme for applications requiring higher regulatory and quality standards | |
Enzyme (degradation / model construction) | 9001-12-1 | Collagenase NB 7D from Clostridium histolyticum | EnzymoPure™, sterile, ≥0.2 U/mg powder | Sterile, high-activity powder for cell-related tissue digestion/degradation assays | |
Enzyme (degradation / model construction) | 9001-12-1 | Collagenase NB 8 from Clostridium histolyticum | EnzymoPure™, broad-spectrum, ≥0.90 U/mg | Broad-spectrum, high-activity enzyme for stronger digestion or complex tissue processing | |
Polymerization inhibitor | 150-76-5 | 4-Methoxyphenol (MEHQ) | 10 mM in DMSO | Common inhibitor; many PEGDA/PEGDMA products contain MEHQ; affects photo-curing rate and conversion (useful for controls, method development, or inhibitor-removal evaluation) | |
Polymerization inhibitor | 150-76-5 | 4-Methoxyphenol (MEHQ) | AR, ≥99% | Same as above; used for inhibition, quality control, or inhibitor-related studies/process optimization | |
Antioxidant / stabilizer | 128-37-0 | 2,6-Di-tert-butyl-4-methylphenol (BHT) | Ultra-pure, ≥99.5% (GC) | Antioxidant/stabilizer; present in some (meth)acrylate monomers; affects radical polymerization kinetics and storage stability | |
Antioxidant / stabilizer | 128-37-0 | 2,6-Di-tert-butyl-4-methylphenol (BHT) | Analytical standard, ≥99.7% (GC) | BHT standard for quality control, method validation, or inhibitor-related research | |
Antioxidant / stabilizer | 128-37-0 | B431698 | Butylated hydroxytoluene | E 321 | Synonym of BHT (food additive code E321); used for antioxidant/stabilization in radical systems |
Photosensitizer / visible-light dye | 632-69-9 | Rose Bengal | ≥90% | Visible-light photosensitizer/photocatalyst component for visible-light crosslinking or photo-controlled reaction development | |
Photosensitizer / visible-light dye | 632-69-9 | Rose Bengal | Biological stain | Same compound (staining grade); used for staining or photosensitization scheme exploration | |
Photosensitizer / visible-light dye | 632-69-9 | Rose Bengal | ≥95% | Higher-purity version | |
Photosensitizer / visible-light dye | 17372-87-1 | Eosin Y (water-soluble) | AR | Eosin Y; visible-light photosensitizer/redox system component for visible-light crosslinking and patterning development | |
Photosensitizer / visible-light dye | 17372-87-1 | Eosin Y (water-soluble) | Dye content 75% | Same compound; specified by dye content | |
Base polymer (PEG, inert substrate/additive) | 25322-68-3 | P432446 | Polyethylene glycol 300 (PEG) | PharmPure™, pharmaceutical grade | Base PEG polymer; used for formulation adjustment, hydrophilic spacers, and solution systems; not crosslinkable unless modified |
Base polymer (PEG, inert substrate/additive) | 25322-68-3 | Poly(ethylene glycol) (PEG) | UltraBio™, molecular biology grade, ultra-pure, Mn 8000 | PEG 8000; high-purity base PEG for formulation, spacers, osmotic control; not directly photo-crosslinkable unless end-modified | |
Base polymer (PEG, inert substrate/additive) | 25322-68-3 | Poly(ethylene glycol) (PEG) | Avg. Mn 3350 | PEG 3350; base PEG used as solubilizer, spacer, formulation additive, or precursor for further modification |