Name: Poly-D-lysine Hydrobromide
Brand: Molecular Depot
SKU: B2018791
Price: 795.00 USD
Availability: InStock

<h2>What are research polymers and PEG derivatives?</h2>
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Research polymers and PEG derivatives are large, defined molecular weight polymer materials used across biochemical research applications: polyethylene glycol (PEG) at defined molecular weights, from small PEG 400 to large PEG 20000, for protein PEGylation, crowding effects, and precipitating nucleic acids or proteins; NHS-ester-activated PEG and other reactive PEG forms for covalent conjugation to amine groups on proteins and nanoparticle surfaces; Ficoll (a sucrose polymer) for density gradient cell separation; dextran as a molecular crowding agent and gel filtration calibration standard; and polyvinyl alcohol for hydrogel preparation.
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<h2 dir="ltr">What you will find:</h2>
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Functionalized PEG Linkers: Multi-arm and linear PEG chains optimized for site-specific bioconjugation and improved payload solubility.
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Biocompatible Synthetic Polymers: High-purity polymeric carriers engineered for controlled substance delivery and tissue engineering research.
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Surface-Modification Polymers: Specialized chemical coatings designed to minimize non-specific protein binding on laboratory substrates.
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Cross-Linking Polymeric Agents: High-efficiency structural linkers prepared for the configuration of stable hydrogels and complex biomaterials.
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<h2>How to choose polymers and PEG derivatives</h2>
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Choose PEG molecular weight based on your application requirements
Lower molecular weight PEGs, such as PEG 400 to PEG 4000, are used for protein precipitation, polyethylene glycol crystallization of proteins for X-ray diffraction, and as cryoprotectants, while higher molecular weight PEGs, such as PEG 8000 to PEG 20000, are used for macromolecular crowding experiments and precipitating DNA and large proteins.
Use NHS-activated PEG for covalent protein or surface PEGylation
NHS-ester-activated PEG reagents react specifically with primary amine groups on proteins (lysine residues and N-terminus) under mild conditions to form a stable amide bond, attaching the PEG chain and creating a PEGylated protein or nanoparticle surface with improved solubility, reduced immunogenicity, and extended half-life.
Use Ficoll 400 for density gradient centrifugation and peripheral blood mononuclear cell isolation
Ficoll 400 at 5.7% in saline, when layered under diluted whole blood, allows separation of peripheral blood mononuclear cells, which migrate to the interface, from erythrocytes and granulocytes that pellet, and from platelets and plasma that remain above. This density gradient separation is the basis of the Ficoll-Hypaque PBMC isolation method.
Use dextran as a molecular crowding agent to mimic cellular conditions
Dextran at concentrations of 10&ndash;40% creates macromolecular crowding conditions in in vitro biochemical assays that better mimic the crowded intracellular environment than dilute aqueous conditions, affecting enzyme kinetics, protein aggregation, and reaction equilibria in ways that can more closely represent physiological behavior.
Confirm the PEG form is appropriate for your downstream application
A methoxy-PEG (mPEG) has one end capped and is used when a single-conjugation is desired; a NHS-PEG-NHS bifunctional form has reactive ends on both termini for crosslinking two molecules; and a NHS-PEG-maleimide heterobifunctional form reacts with amines at one end and thiols at the other, enabling sequential conjugation of two different molecules.
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<h2>Specifications context</h2>
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Ficoll, a registered trademark of Cytiva, is specifically a high-molecular-weight sucrose polymer of approximately 400,000 Da that is dense, hydrophilic, and non-toxic to cells, properties that allow the formation of stable density gradients without the cytotoxicity of some alternative gradient media. As of 2026, branched PEG architectures and brush-PEG coatings continue to be used for nanoparticle surface stealth coating in drug delivery research, alongside the well-established NHS-activated linear PEG conjugation chemistry that remains the standard approach for therapeutic protein PEGylation.
<a href="https://mbpinc.net/contact-us" title="Contact the helpful team">Contact the helpful team</a> at MBP today to request a quote for your specific research requirements.

Polymers & PEG Derivatives

Molecular Depot

Key Specifications

Poly-D-lysine Hydrobromide

Poly-D-lysine Hydrobromide by Molecular Depot is a poly-D-lysine hydrobromide, a polycationic homopolymer of D-lysine used to improve cell attachment in culture. Its positive charge binds the negatively charged surfaces of cells and of culture plastic. It is used as a culture surface coating, particularly for primary neurons, and as a polycation in layer-by-layer assembly. Each unit contains 25 mg. MBP supplies Molecular Depot polymer reagents to research labs in the United States, Canada and worldwide.