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MAL-dPEG®₈-TFP ester

MAL-dPEG®₈-TFP ester

TFP_Esters_Art2MAL-dPEG®8-TFP ester, product number 10552, is a crosslinking reagent that joins a sulfhydryl to a free amine. The sulfhydryl groups react with a maleimide group via a Michael addition reaction. The amines form amide bonds with the crosslinker by nucleophilic substitution of the 2,3,5,6-tetrafluorophenyl (TFP) ester of the terminal propionic acid group. The maleimide and TFP functional groups on the crosslinking compound sit at either end of a medium-length, discrete polyethylene glycol (dPEG®) chain. The single molecular weight dPEG® spacer is 38 atoms (37.9 Å) long.
Crosslinking ReactionsOne of the most popular, most useful crosslinking reactions in bioconjugate chemistry[1],[2] is the conjugation of free amines to free thiols. These reactions require heterobifunctional reagents that bridge the two groups. Typical crosslinkers are hydrophobic. Quanta BioDesign's dPEG® crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths.With conventional hydrophobic crosslinking reagents, aggregation and precipitation of the conjugates occur frequently. These problems do not happen with our water-soluble, non-immunogenic dPEG® crosslinkers. For more information about our dPEG® products, please see our "What is dPEG®?" page. Also, please click here for answers to our most frequently asked questions.TFP Esters are Superior to NHS estersTFP esters are more stable in aqueous buffers than N-hydroxysuccinimidyl (NHS) esters. Moreover, TFP esters have higher reactivity with free amines than NHS esters.[3] NHS esters hydrolyze readily in water or aqueous buffer. As the pH increases, the hydrolysis rate of the NHS ester increases.[4] In 2017, a study by J. Wang, et al., on the performance of fluorophenyl esters concluded, "With regards to PEGylation, the TFP ester performed better than NHS ester."[5] In-house research at Quanta BioDesign confirms the superior performance of TFP esters over NHS esters.How to Use MAL-dPEG®8-TFP esterTFP esters react under the same conditions as NHS esters. However, the optimal pH range for TFP esters (7.5 – 8.0) is slightly higher than for NHS esters (7.0 – 7.5).5 Amide bond formation between the TFP-activated propionic acid group of MAL-dPEG®8-TFP ester and a free amine will be slightly slower at a suboptimal pH compared to the reaction rate within the optimum pH range. Nevertheless, the reaction rate remains relatively rapid.The reaction of the maleimide end of MAL-dPEG®8-TFP ester, product number 10552, with a sulfhydryl proceeds best at pH 6.5 – 7.5. Conduct the conjugation at the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which can cause confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.[6] For details about maleimide-thiol reaction chemistry, please click here.Uses of MAL-dPEG®8-TFP esterMAL-dPEG®8-TFP ester, product number 10552, can be used the same way and in the same applications as the equivalent NHS esters. A 2019 study used PN10552 from Quanta BioDesign to synthesize pyrrolobenzodiazepine dimer antibody-drug conjugates with dual β-glucuronide and dipeptide triggers.[7] Other possible uses for this product include the following:
  • Coating nanoparticle surfaces;
  • Tethering antibodies to atomic force microscopy (AFM) probes;
  • Increasing the water solubility and hydrodynamic volume of hydrophobic biomolecules;
  • Building supramolecular constructs; and,
  • Conjugating the TFP ester end of the molecule a liposomal surface and then using the free maleimide end of the molecule to attach a small molecule drug, peptide, or antibody for targeted delivery of a diagnostic or therapeutic package.
How will you use this product?Bulk Scale Synthesis of MAL-dPEG®8-TFP ester is AvailableIf you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.Buy Now!Hydrophobic crosslinkers create more problems than they solve. Traditional disperse polymer PEG crosslinkers add unnecessary analytical complexity to conjugates that incorporate them.So, stop using inferior products!Start using single molecular weight dPEG® crosslinkers and discover the dPEG® difference. To get started, please click the "Add to Cart" button now to order MAL-dPEG®8-TFP ester, product number 10552.Application References:[1] Hermanson, G. T. Chapter 6, Heterobifunctional Crosslinkers. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 299–340, specifically page 300. Many scientists engaged in bioconjugation work consider Greg Hermanson's book to be the definitive reference on the subject. Click here now to read a review of Greg's book and to purchase it.[2] Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 787–838, specifically page 794.[3] Hermanson, G. T. Chapter 3, The Reactions of Bioconjugation. In Bioconjugate Techniques; Academic Press: New York, NY, 2013; pp 229–258, specifically page 239.[4] Ibid, page 234.[5] Wang, J.; Zhang, R.-Y.; Wang, Y.-C.; Chen, X.-Z.; Yin, X.-G.; Du, J.-J.; Lei, Z.; Xin, L.-M.; Gao, X.-F.; Liu, Z.; et al. Polyfluorophenyl Ester-Terminated Homobifunctional Cross-Linkers for Protein Conjugation. Synlett 2017, 28 (15), 1934–1938. https://doi.org/10.1055/s-0036-1590974.[6] Hermanson, G. T. Chapter 6, op. cit., page 304.[7] Gregson, S. J.; Barrett, A. M.; Patel, N. V.; Kang, G.-D.; Schiavone, D.; Sult, E.; Barry, C. S.; Vijayakrishnan, B.; Adams, L. R.; Masterson, L. A.; et al. Synthesis and Evaluation of Pyrrolobenzodiazepine Dimer Antibody-Drug Conjugates with Dual β-Glucuronide and Dipeptide Triggers. European Journal of Medicinal Chemistry 2019, 179, 591–607. https://doi.org/10.1016/j.ejmech.2019.06.044.
 
MAL-dPEG®₂-NHS ester

MAL-dPEG®₂-NHS ester

TFP_Esters_Art2MAL-dPEG®2-NHS ester, product number 10266, is a crosslinking reagent that joins a sulfhydryl to a free amine. The sulfhydryl groups react with a maleimide group via a Michael addition reaction. The amines form amide bonds with the crosslinker by nucleophilic substitution of the N-hydroxysuccinimidyl (NHS) ester of a carboxylic acid group. The maleimide and NHS functional groups on the crosslinking compound sit at either end of a short, discrete-length polyethylene glycol chain (dPEG®). The single molecular weight dPEG® spacer is 16 atoms and 17.7 Å long.
One of the most popular[1], most useful[2] crosslinking reactions in bioconjugate chemistry is the reaction that joins a sulfhydryl group to a free amine. These reactions require heterobifunctional reagents that bridge the two different reactive groups. Initially, such reagents were initially hydrophobic. Now, Quanta BioDesign's dPEG® products are single molecular weight PEG compounds with discrete chain lengths. Our amphiphilic dPEG® products impart water solubility to conjugates containing them.Consequently, the problems that accompany hydrophobic crosslinking reagents, such as aggregation and precipitation of biomolecular conjugates, do not exist with dPEG® crosslinkers. For more information about our dPEG® products, please see our "What is dPEG®?" page. Also, click here for answers to our most frequently asked questions.The NHS ester hydrolyzes readily in water or aqueous buffer. Therefore, conjugation of this end of the molecule should occur before conjugation of the maleimide end of the crosslinker. At pH 7.0 – 7.5, NHS esters react optimally with free amines. However, NHS esters can react with free amines with pH as low as 6.0. As the pH increases, the hydrolysis rate of the ester increases. Thus, we strongly discourage storing MAL-dPEG®2-NHS ester, product number 10266, in water or aqueous buffer. Instead, we recommend that customers make new solutions of the product as needed, use them immediately, and discard unused solutions after use.The reaction of the maleimide end of MAL-dPEG®2-NHS ester, product number 10266, proceeds optimally at pH 6.5 – 7.5. Use the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which can cause confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.[3] For details about maleimide-thiol reaction chemistry, please click here.The use of MAL-dPEG®2-NHS ester, product number 10266, has been published in many different scientific paper and patents. The following list highlights some of the more notable uses of this product:
  • Cell targeting;
  • Crosslinking peptides to passivated nanoparticle surfaces;
  • Stem cell membrane engineering;
  • Biosensor development;
  • Cell capture using aptamers;
  • Controlled, targeted delivery of siRNA;
  • Development of extracellular antibody drug conjugates; and,
  • Development of multiplex assays.
What can you do with this product? Please click the "Add to Cart" button now to order MAL-dPEG®2-NHS ester, product number 10266.Application References:[1] Hermanson, G. T. Chapter 6, Heterobifunctional Crosslinkers. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 299–340, specifically p. 300. Many scientists engaged in bioconjugation work consider Greg Hermanson's book to be the definitive reference on the subject. Click here now to read a review of Greg's book and to purchase it.[2] Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 787–838, specifically p. 794.[3] Hermanson, G. T. Chapter 6, op. cit., page 304.
MAL-dPEG®₃₆-TFP ester

MAL-dPEG®₃₆-TFP ester

TFP_Esters_Art2MAL-dPEG®36-TFP ester, product number 10555, is a crosslinking reagent that joins a sulfhydryl to a free amine. The sulfhydryl groups react with a maleimide group via a Michael addition reaction. The amines form amide bonds with the crosslinker by nucleophilic substitution of the 2,3,5,6-tetrafluorophenyl (TFP) ester of the terminal propionic acid group. The maleimide and TFP functional groups on the crosslinking compound sit at either end of a discrete-length polyethylene glycol (dPEG®) chain. The single molecular weight dPEG® spacer is 117 atoms and 139.7 Å long.
Crosslinking ReactionsOne of the most popular, most useful crosslinking reactions in bioconjugate chemistry [1],[2] is the conjugation of free amines to free thiols. These reactions require heterobifunctional reagents that bridge the two groups. Typical crosslinkers are hydrophobic. Quanta BioDesign's dPEG® crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths.With conventional hydrophobic crosslinking reagents, aggregation and precipitation of the conjugates occur frequently. These problems do not happen with our water-soluble, non-immunogenic dPEG® crosslinkers. For more information about our dPEG® products, please see our "What is dPEG®?" page. Also, click here for answers to our most frequently asked questions.TFP Esters are Superior to NHS estersTFP esters are more stable in aqueous buffers than N-hydroxysuccinimidyl (NHS) esters. Moreover, TFP esters have higher reactivity with free amines than NHS esters.[3] NHS esters hydrolyze readily in water or aqueous buffer. As the pH increases, the hydrolysis rate of the NHS ester increases.[4] In 2017, a study by J. Wang, et al., on the performance of fluorophenyl esters concluded, "With regards to PEGylation, the TFP ester performed better than NHS ester."[5] These superior characteristics of TFP esters have been confirmed by in-house research at Quanta BioDesign.How to Use MAL-dPEG®36-TFP esterTFP esters react under the same conditions as NHS esters. However, the optimal pH range for TFP esters (7.5 – 8.0) is slightly higher than for NHS esters (7.0 – 7.5). Amide bond formation between the TFP-activated propionic acid group of MAL-dPEG®36-TFP ester and a free amine will be slightly slower at a sub-optimal pH compared to the reaction rate within the optimum pH range.The reaction of the maleimide end of MAL-dPEG®36-TFP ester, product number 10555, with a sulfhydryl proceeds best at pH 6.5 – 7.5. Conduct the conjugation at the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which can cause confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.[6] For details about maleimide-thiol reaction chemistry, please click here.Uses of MAL-dPEG®36-TFP esterMAL-dPEG®36-TFP ester, product number 10555, can be used the same way and in the same applications as the equivalent NHS esters. These uses include the following:
  • Coating nanoparticle surfaces;
  • Tethering antibodies to atomic force microscopy (AFM) probes;
  • Constructing antibody-drug conjugates (ADCs);
  • Increasing the water solubility and hydrodynamic volume of hydrophobic biomolecules;
  • Building supramolecular constructs; and,
  • Conjugating the TFP ester end of the molecule a liposomal surface and then using the free maleimide end of the molecule to attach a small molecule drug, peptide, or antibody for targeted delivery of a diagnostic or therapeutic package.
What can you do with this product?Bulk Scale Synthesis of MAL-dPEG®36-TFP ester is AvailableIf you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.Buy Now!Hydrophobic crosslinkers create more problems than they solve. Traditional disperse polymer PEG crosslinkers add unnecessary analytical complexity to conjugates that incorporate them.So, stop using inferior products!Start using single molecular weight dPEG® crosslinkers and discover the dPEG® difference. To get started, please click the "Add to Cart" button now to order MAL-dPEG®36-TFP ester, product number 10555.Application References:[1] Hermanson, G. T. Chapter 6, Heterobifunctional Crosslinkers. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 299–340, specifically page 300. Many scientists engaged in bioconjugation work consider Greg Hermanson's book to be the definitive reference on the subject. Click here now to read a review of Greg's book and to purchase it.[2] Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 787–838, specifically page 794.[3] Hermanson, G. T. Chapter 3, The Reactions of Bioconjugation. In Bioconjugate Techniques; Academic Press: New York, NY, 2013; pp 229–258, specifically page 239.[4] Ibid, page 234.[5] Wang, J.; Zhang, R.-Y.; Wang, Y.-C.; Chen, X.-Z.; Yin, X.-G.; Du, J.-J.; Lei, Z.; Xin, L.-M.; Gao, X.-F.; Liu, Z.; et al. Polyfluorophenyl Ester-Terminated Homobifunctional Cross-Linkers for Protein Conjugation. Synlett 2017, 28 (15), 1934–1938. https://doi.org/10.1055/s-0036-1590974.[6] Hermanson, G. T. Chapter 6, op. cit., page 304.
MAL-dPEG®₄-Tris(-TFP ester)₃

MAL-dPEG®₄-Tris(-TFP ester)₃

MAL-dPEG®4-Tris(TFP ester)3, product number 11416, is a unique crosslinking, monodisperse PEGylation reagent from Quanta BioDesign. This single molecular weight, discrete-length PEG (dPEG®) product permits one-to-three crosslinking of thiol and amine groups. The single maleimido group on one end of the dPEG® linker reacts with free thiols. On the opposite end of the molecule, a tris-based branching structure that terminates with propionic acid groups permits crosslinking with three different amino groups. The crosslinker length from the maleimido olefin to the terminal carbonyl carbon adjacent to the 2,3,5,6-tetrafluorophenyl (TFP) ester is 29 atoms (24.7 Å, avg.) long.
What are the uses of MAL-dPEG®4-Tris(TFP ester)3?The well-known thiol-maleimide reaction permits conjugation of the maleimide group to free thiols. Because cysteine residues are comparatively rare in proteins, the thiol-maleimide reaction gives the user more control over the site(s) of conjugation. Scientists often make use of this reaction in the construction of antibody-drug conjugates (ADCs). The thiol-maleimide reaction is specific for free thiols at pH 6.5 – 7.5. However, specificity disappears above pH 7.5, as the maleimido group reacts with free amines such as the primary amine on the side chain of lysine. To learn more about the thiol-maleimide reaction, please visit our Maleimide Reaction Chemistry page.The TFP ester reacts with free amines similarly to the more well-known N-hydroxysuccinimide (NHS) esters. Research, though, shows that TFP esters are more hydrolytically stable and reactive than NHS esters in aqueous media. Thus, TFP esters are a superior alternative to NHS esters. For more information on TFP esters, please click here.The potential applications of MAL-dPEG®4-Tris(TFP ester)3 are limitless. Some possible uses for this product include the following:
  • Construction of dendrimers and other supramolecular constructs;
  • Creation of ADCs;
  • Modification of hydrogels with surface-accessible sulfhydryl groups; and,
  • Crosslinking small biomolecules such as peptides to create a targeted delivery vehicle.
Learn more about Quanta BioDesign's dPEG® Technology!What is dPEG®?Frequently Asked Questions (about dPEG® products)Is MAL-dPEG®4-Tris(TFP ester)3 Available in Bulk Quantities?Yes, it is. If you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.Buy It Now!This unique crosslinking PEGylation reagent from Quanta BioDesign offers all the benefits of traditional PEG products without the analytical complexity caused by dispersity. Our products have no dispersity. Each dPEG® product has a single molecular weight, discrete chain length PEG.To get started, please click the "Add to Cart" button now.
MAL-dPEG®₂₄-NHS ester

MAL-dPEG®₂₄-NHS ester

TFP_Esters_Art2MAL-dPEG®24-NHS ester, product number 10314, is a crosslinking reagent that joins a sulfhydryl to a free amine. The sulfhydryl groups react with a maleimide group via a Michael addition reaction. The amines form amide bonds with the crosslinker by nucleophilic substitution of the N-hydroxysuccinimidyl (NHS) ester of a carboxylic acid group. The maleimide and NHS functional groups on the crosslinking compound sit at either end of a long, discrete-length polyethylene glycol chain (dPEG®). The single molecular weight dPEG® spacer is 82 atoms and 95.2 Å long.
The joining of free amines to sulfhydryl groups is one of the most popular[1], most useful[2] crosslinking reactions in bioconjugate chemistry. These reactions require heterobifunctional reagents that bridge the two groups. Traditional crosslinkers are hydrophobic molecules. Quanta BioDesign's dPEG® crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths.The conjugation of conventional hydrophobic crosslinking reagents to biomolecules almost inevitably triggers problems such as aggregation and precipitation of the conjugates. These problems do not occur with our water-soluble, non-immunogenic dPEG® crosslinkers. For more information about our dPEG® products, please see our "What is dPEG®?" page. Also, click here for answers to our most frequently asked questions.How to Use MAL-dPEG®24-NHS esterBecause NHS esters hydrolyze readily in water or aqueous buffer, the NHS ester end of the molecule must conjugate to a target molecule before conjugating the maleimide end of the molecule. At pH 7.0 – 7.5, NHS esters react optimally with free amines. However, NHS esters can react with free amines with pH as low as 6.0. As the pH increases, the hydrolysis rate of the NHS ester increases. Indeed, at pH 7 and 0°C, the NHS ester half-life is four (4) to five (5) hours in aqueous buffer, while at pH 8 and 25°C, the half-life of an NHS ester is one hour.[3] Thus, we strongly discourage storing MAL-dPEG®24-NHS ester, product number 10314, in water or aqueous buffer. Instead, we recommend that customers make new solutions of the product as needed, use them immediately, and discard unused solutions after use.The reaction of the maleimide end of MAL-dPEG®24-NHS ester, product number 10314, with a sulfhydryl proceeds best at pH 6.5 – 7.5. Conduct the conjugation at the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which can cause confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.[4] For details about maleimide-thiol reaction chemistry, please click here.Uses of MAL-dPEG®24-NHS esterThe use of MAL-dPEG®24-NHS ester, product number 10314, has been published in numerous scientific paper and patents. The following list highlights some of the more important uses of this product:
  • targeted delivery of a cancer drug via polylysine dendrimers;
  • targeted delivery of drugs to the lungs;
  • development of a blood purification device using magnetic nanoparticles;
  • development of a targeted therapeutic system using superparamagnetic nanoparticles;
  • improved transfection of tumor cells by PEGylated liposomes;
  • development of immunosensors and biosensors;
  • investigation of an aptamer using atomic force microscopy;
  • attaching antibodies to atomic force microscopy probes;
  • development of molecular pincers;
  • improvement of a peptidic ligand used for capture and purification of IgM; and,
  • surface coating of nanoparticles.
What can you do with this product?Please click the "Add to Cart" button now to order MAL-dPEG®24-NHS ester, product number 10314.Application References:[1] Hermanson, G. T. Chapter 6, Heterobifunctional Crosslinkers. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 299–340, specifically page 300. Many scientists engaged in bioconjugation work consider Greg Hermanson's book to be the definitive reference on the subject. Click here now to read a review of Greg's book and to purchase it.[2] Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 787–838, specifically page 794.[3] Hermanson, G. T. Chapter 3, The Reactions of Bioconjugation. In Bioconjugate Techniques; Academic Press: New York, NY, 2013; pp 229–258, specifically page 234.[4] Hermanson, G. T. Chapter 6, op. cit., page 304.
MAL-dPEG®₁₂-Tris(-TFP ester)₃

MAL-dPEG®₁₂-Tris(-TFP ester)₃

MAL-dPEG®12-Tris(TFP ester)3, product number 11427, is a unique, monodisperse, crosslinking PEGylation reagent from Quanta BioDesign. Slightly longer than the companion product, PN11416, this single molecular weight, discrete-length PEG (dPEG®) product permits one-to-three crosslinking of thiol and amine groups. The maleimido group on one end of the molecule reacts with free thiols. On the opposite end, a tris-based branching structure that terminates with propionic acid groups permits crosslinking with three different amino groups. The crosslinker length from the maleimido olefin to the terminal carbonyl carbon adjacent to the 2,3,5,6-tetrafluorophenyl (TFP) ester is 47 atoms (67.2 – 68.2 Å) long.
What is dPEG®?Unlike conventional PEGylation reagents, monodisperse dPEG® products have a single molecular weight of PEG, and the PEG chain possesses a discrete length. There is no distribution of molecular weights and PEG chain lengths. Because dPEG® products are single molecules, the analysis and characterization of conjugates made with dPEG® products are enormously simplified compared to products made with dispersed PEG products. Quanta BioDesign sells our products under the dPEG® tradename to highlight the fact that we do not purify from a polymer mixture but synthesize them to the desired chain length starting from short, highly pure starting materials.Learn more about Quanta BioDesign's dPEG® Technology!What is dPEG®?Frequently Asked Questions (about dPEG® products)Uses of MAL-dPEG®12-Tris(TFP ester)3The well-known thiol-maleimide reaction conjugates a maleimide functional group to a free thiol such as is found on the side chain of the amino acid cysteine. Because proteins typically possess relatively few cysteine residues compared to other amino acids, the user gains control over the site(s) of conjugation. Scientists often use thiol-maleimide chemistry in the construction of antibody-drug conjugates (ADCs) because it is specific for free thiols at pH 6.5 – 7.5. However, specificity disappears above pH 7.5, as the maleimido group reacts with free amines such as the primary amine on the side chain of lysine. To learn more about the thiol-maleimide reaction, please visit our Maleimide Reaction Chemistry page.The TFP ester reacts with free amines similarly to the more well-known N-hydroxysuccinimide (NHS) esters. Research, though, shows that TFP esters are more hydrolytically stable and reactive than NHS esters in aqueous media. Thus, TFP esters are a superior alternative to NHS esters. For more information on TFP esters, please click here.The potential applications of MAL-dPEG®12-Tris(TFP ester)3 are limitless. Some possible uses for this product include the following:
  • Construction of dendrimers and other supramolecular constructs;
  • Creation of ADCs;
  • Modification of hydrogels with surface-accessible sulfhydryl groups; and,
  • Crosslinking small biomolecules such as peptides to create a targeted delivery vehicle.
Bulk Quantities of MAL-dPEG®12-Tris(TFP ester)3If you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.Buy It Now!This unique crosslinking PEGylation reagent from Quanta BioDesign offers all the benefits of traditional PEG products without the analytical complexity caused by dispersity. Our products have no dispersity. Each dPEG® product has a single molecular weight, discrete chain length PEG.To get started, please click the "Add to Cart" button now.
MAL-dPEG®₈-NHS ester

MAL-dPEG®₈-NHS ester

TFP_Esters_Art2MAL-dPEG®8-NHS ester, product number 10274, is a crosslinker that joins a sulfhydryl to a free amine through a hydrophilic bridge. The sulfhydryl groups react with a maleimide group via a Michael addition reaction. The amines form amide bonds with the crosslinker by nucleophilic substitution of the N-hydroxysuccinimidyl (NHS) ester of a carboxylic acid group. The maleimide and NHS functional groups on the crosslinking compound sit at either end of a discrete-length polyethylene glycol chain (dPEG®). The single molecular weight dPEG® spacer is 34 atoms and 39.2 Å long.
Crosslinking with dPEG® ProductsAmong the most popular[1], most useful[2] crosslinking reactions in bioconjugate chemistry are reactions that join free amines with free thiols. These reactions require heterobifunctional reagents that bridge the two groups. Traditional crosslinkers are hydrophobic molecules. Quanta BioDesign's dPEG® crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths.The conjugation of conventional hydrophobic crosslinking reagents to biomolecules almost inevitably triggers problems such as aggregation and precipitation of the conjugates. These problems do not occur with our water-soluble, non-immunogenic dPEG® crosslinkers. For more information about our dPEG® products, please see our "What is dPEG®?" page. Also, click here for answers to our most frequently asked questions.How to Use MAL-dPEG®8-NHS esterBecause NHS esters hydrolyze readily in water or aqueous buffer, the NHS ester end of the molecule must conjugate to a target molecule before conjugating the maleimide end of the molecule. At pH 7.0 – 7.5, NHS esters react optimally with free amines. However, NHS esters can react with free amines with pH as low as 6.0. As the pH increases, the hydrolysis rate of the NHS ester increases. Indeed, at pH 8 and 25°C, the half-life of an NHS ester in aqueous media is one hour, while at pH 8.6 and 4°C, the half-life falls to ten (10) minutes.[3] Thus, we strongly discourage storing MAL-dPEG®8-NHS ester, product number 10274, in water or aqueous buffer. Instead, we recommend that customers make new solutions of the product as needed, use them immediately, and discard unused solutions after use.The reaction of the maleimide end of MAL-dPEG®8-NHS ester, product number 10274, with a sulfhydryl proceeds optimally at pH 6.5 – 7.5. Use the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which can cause confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.[4] For details about maleimide-thiol reaction chemistry, please click here.Uses of MAL-dPEG®8-NHS esterThe use of MAL-dPEG®8-NHS ester, product number 10274, has been published in numerous scientific paper and patents. The following list highlights some of the more important uses of this product:
  • development of molecular pincers;
  • development of fluorescent immunosensors for pathogenic bacteria;
  • crosslinking proteins to hydrogels;
  • development of antibody-drug conjugates (ADCs)
  • development of a detection methodology for single-stranded oligonucleotides;
  • crosslinking HIV-1 envelope proteins;
  • development of imaging applications;
  • development of immunoassays; and,
  • surface coating of nanoparticles.
What can you do with this product?Please click the "Add to Cart" button now to order MAL-dPEG®8-NHS ester, product number 10274.Application References:[1] Hermanson, G. T. Chapter 6, Heterobifunctional Crosslinkers. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 299–340, specifically page 300. Many scientists engaged in bioconjugation work consider Greg Hermanson's book to be the definitive reference on the subject. Click here now to read a review of Greg's book and to purchase it.[2] Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 787–838, specifically page 794.[3] Hermanson, G. T. Chapter 3, The Reactions of Bioconjugation. In Bioconjugate Techniques; Academic Press: New York, NY, 2013; pp 229–258, specifically page 234.[4] Hermanson, G. T. Chapter 6, op. cit., page 304.
MAL-dPEG®₄-TFP ester

MAL-dPEG®₄-TFP ester

TFP_Esters_Art2MAL-dPEG®4-TFP ester, product number 10551, is a crosslinking reagent that joins free amines to free thiols (sulfhydryl groups). The sulfhydryl groups react with a maleimido group via a Michael addition reaction. The amines form amide bonds with the crosslinker by nucleophilic substitution of the 2,3,5,6-tetrafluorophenyl (TFP) ester of the terminal propionic acid group. The maleimido and TFP functional groups on the crosslinking compound sit at either end of a short, discrete chain of polyethylene glycol (hence, dPEG®). The single molecular weight dPEG® spacer is 22 atoms (24.1 Å) long.

Crosslinking Reactions

One of the most popular, most useful crosslinking reactions in bioconjugate chemistry[1],[2] is the conjugation of free amines to free thiols. These reactions require heterobifunctional reagents that bridge the two groups. Typical crosslinkers are hydrophobic. Quanta BioDesign's dPEG® crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths.With conventional hydrophobic crosslinking reagents, aggregation and precipitation of the conjugates occur frequently. These problems do not happen with our water-soluble, non-immunogenic dPEG® crosslinkers. For more information about our dPEG® products, please see our "What is dPEG®?" page. Also, click here for answers to our most frequently asked questions.

TFP Esters are Superior to NHS esters

TFP esters are more stable in aqueous buffers than N-hydroxysuccinimidyl (NHS) esters. Moreover, TFP esters have higher reactivity with free amines than NHS esters.[3] NHS esters hydrolyze readily in water or aqueous buffer. As the pH increases, the hydrolysis rate of the NHS ester increases.[4] In 2017, a study by J. Wang, et al., on the performance of fluorophenyl esters concluded, "With regards to PEGylation, the TFP ester performed better than NHS ester."[5] In-house research at Quanta BioDesign confirms the superior performance of TFP esters over NHS esters.

How to Use MAL-dPEG®4-TFP ester

TFP esters react under the same conditions as NHS esters. However, the optimal pH range for TFP esters (7.5 – 8.0) is slightly higher than for NHS esters (7.0 – 7.5).5 Amide bond formation between the TFP-activated propionic acid group of MAL-dPEG®4-TFP ester and a free amine will be slightly slower at a suboptimal pH compared to the reaction rate within the optimum pH range.The maleimide end of MAL-dPEG®4-TFP ester, product number 10551, reacts optimally with a sulfhydryl at pH 6.5 – 7.5. Conduct the conjugation at the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which may confound the data. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.[6] For details about maleimide-thiol reaction chemistry, please click here.

Uses of MAL-dPEG®4-TFP ester

MAL-dPEG®4-TFP ester, product number 10551, can be used the same way and in the same applications as the equivalent NHS esters. Possible uses for this product include the following:
  • Coating nanoparticle surfaces;
  • Tethering antibodies to atomic force microscopy (AFM) probes;
  • Constructing antibody-drug conjugates (ADCs);
  • Adding flexibility and water solubility to a peptide;
  • Increasing the water solubility and hydrodynamic volume of hydrophobic biomolecules;
  • Building supramolecular constructs; and,
  • Conjugating the TFP ester end of the molecule a liposomal surface and then using the free maleimide end of the molecule to attach a small molecule drug, peptide, or antibody for targeted delivery of a diagnostic or therapeutic package.
How do you plan to utilize this product's potential?

Bulk Scale Synthesis of MAL-dPEG®4-TFP ester is Available

If you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.Buy Now!Hydrophobic crosslinkers create more problems than they solve. Traditional disperse polymer PEG crosslinkers add unnecessary analytical complexity to conjugates that incorporate them.So, stop using inferior products!Start using single molecular weight dPEG® crosslinkers and discover the dPEG® difference. To get started, please click the "Add to Cart" button now to order MAL-dPEG®4-TFP ester, product number 10551.Application References:[1] Hermanson, G. T. Chapter 6, Heterobifunctional Crosslinkers. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 299–340, specifically page 300. Many scientists engaged in bioconjugation work consider Greg Hermanson's book to be the definitive reference on the subject. Click here now to read a review of Greg's book and to purchase it.[2] Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 787–838, specifically page 794.[3] Hermanson, G. T. Chapter 3, The Reactions of Bioconjugation. In Bioconjugate Techniques; Academic Press: New York, NY, 2013; pp 229–258, specifically page 239.[4] Ibid, page 234.[5] Wang, J.; Zhang, R.-Y.; Wang, Y.-C.; Chen, X.-Z.; Yin, X.-G.; Du, J.-J.; Lei, Z.; Xin, L.-M.; Gao, X.-F.; Liu, Z.; et al. Polyfluorophenyl Ester-Terminated Homobifunctional Cross-Linkers for Protein Conjugation. Synlett 2017, 28 (15), 1934–1938. https://doi.org/10.1055/s-0036-1590974.[6] Hermanson, G. T. Chapter 6, op. cit., page 304.
 
MAL-dPEG®₂-TFP ester

MAL-dPEG®₂-TFP ester

TFP_Esters_Art2MAL-dPEG®2-TFP ester, product number 10549, is a crosslinking reagent that joins free amines to free thiols (sulfhydryl groups). The sulfhydryl groups react with a maleimido group via a Michael addition reaction. The amines form amide bonds with the crosslinker by nucleophilic substitution of the 2,3,5,6-tetrafluorophenyl (TFP) ester of the terminal propionic acid group. The maleimido and TFP functional groups on the crosslinking compound sit at either end of a short, discrete polyethylene glycol (dPEG®) chain. The single molecular weight dPEG® spacer is 16 atoms (17.3 Å) long.

Crosslinking Reactions

One of the most popular, most useful crosslinking reactions in bioconjugate chemistry[1],[2] is the conjugation of free amines to free thiols. These reactions require heterobifunctional reagents that bridge the two groups. Typical crosslinkers are hydrophobic. Quanta BioDesign's dPEG® crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths.With conventional hydrophobic crosslinking reagents, aggregation and precipitation of the conjugates occur frequently. These problems do not happen with our water-soluble, non-immunogenic dPEG® crosslinkers. For more information about our dPEG® products, please see our "What is dPEG®?" page. Also, click here for answers to our most frequently asked questions.

TFP Esters are Superior to NHS esters

TFP esters are more stable in aqueous buffers than N-hydroxysuccinimidyl (NHS) esters. Moreover, TFP esters have higher reactivity with free amines than NHS esters.[3] NHS esters hydrolyze readily in water or aqueous buffer. As the pH increases, the hydrolysis rate of the NHS ester increases.[4] In 2017, a study by J. Wang, et al., on the performance of fluorophenyl esters concluded, "With regards to PEGylation, the TFP ester performed better than NHS ester."[5] These superior characteristics of TFP esters have been confirmed by in-house research at Quanta BioDesign.

How to Use MAL-dPEG®2-TFP ester

TFP esters react under the same conditions as NHS esters. However, the optimal pH range for TFP esters (7.5 – 8.0) is slightly higher than for NHS esters (7.0 – 7.5).5 Amide bond formation between the TFP-activated propionic acid group of MAL-dPEG®2-TFP ester and a free amine will be slightly slower at a suboptimal pH compared to the reaction rate within the optimum pH range.The maleimide end of MAL-dPEG®2-TFP ester, product number 10549, reacts optimally with a sulfhydryl at pH 6.5 – 7.5. Conduct the conjugation at the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which may confound the data. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.[6] For details about maleimide-thiol reaction chemistry, please click here.Uses of MAL-dPEG®2-TFP esterMAL-dPEG®2-TFP ester, product number 10549, can be used the same way and in the same applications as the equivalent NHS esters. Possible uses for this product include the following:
  • Coating nanoparticle surfaces;
  • Tethering antibodies to atomic force microscopy (AFM) probes;
  • Constructing antibody-drug conjugates (ADCs);
  • Adding flexibility and water solubility to a peptide;
  • Increasing the water solubility and hydrodynamic volume of hydrophobic biomolecules;
  • Building supramolecular constructs; and,
  • Conjugating the TFP ester end of the molecule a liposomal surface and then using the free maleimide end of the molecule to attach a small molecule drug, peptide, or antibody for targeted delivery of a diagnostic or therapeutic package.
How will you use this product?

Bulk Scale Synthesis of MAL-dPEG®2-TFP ester is Available

If you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.Buy Now!Hydrophobic crosslinkers create more problems than they solve. Traditional disperse polymer PEG crosslinkers add unnecessary analytical complexity to conjugates that incorporate them.So, stop using inferior products!Start using single molecular weight dPEG® crosslinkers and discover the dPEG® difference. To get started, please click the "Add to Cart" button now to order MAL-dPEG®2-TFP ester, product number 10549.Application References:[1] Hermanson, G. T. Chapter 6, Heterobifunctional Crosslinkers. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 299–340, specifically page 300. Many scientists engaged in bioconjugation work consider Greg Hermanson's book to be the definitive reference on the subject. Click here now to read a review of Greg's book and to purchase it.[2] Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 787–838, specifically page 794.[3] Hermanson, G. T. Chapter 3, The Reactions of Bioconjugation. In Bioconjugate Techniques; Academic Press: New York, NY, 2013; pp 229–258, specifically page 239.[4] Ibid, page 234.[5] Wang, J.; Zhang, R.-Y.; Wang, Y.-C.; Chen, X.-Z.; Yin, X.-G.; Du, J.-J.; Lei, Z.; Xin, L.-M.; Gao, X.-F.; Liu, Z.; et al. Polyfluorophenyl Ester-Terminated Homobifunctional Cross-Linkers for Protein Conjugation. Synlett 2017, 28 (15), 1934–1938. https://doi.org/10.1055/s-0036-1590974.[6] Hermanson, G. T. Chapter 6, op. cit., page 304.
 
MAL-dPEG®₁₂-TFP ester

MAL-dPEG®₁₂-TFP ester

TFP_Esters_Art2MAL-dPEG®12-TFP ester, product number 10553, is a crosslinking reagent that joins a sulfhydryl to a free amine. The sulfhydryl groups react with a maleimide group via a Michael addition reaction. The amines form amide bonds with the crosslinker by nucleophilic substitution of the 2,3,5,6-tetrafluorophenyl (TFP) ester of the terminal propionic acid group. The maleimide and TFP functional groups on the crosslinking compound sit at either end of a medium-length, discrete polyethylene glycol (dPEG®) chain. The single molecular weight dPEG® spacer is 49 atoms (51.1 Å) long.
Crosslinking ReactionsOne of the most popular, most useful crosslinking reactions in bioconjugate chemistry[1],[2] is the conjugation of free amines to free thiols. These reactions require heterobifunctional reagents that bridge the two groups. Typical crosslinkers are hydrophobic. Quanta BioDesign's dPEG® crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths.With conventional hydrophobic crosslinking reagents, aggregation and precipitation of the conjugates occur frequently. These problems do not happen with our water-soluble, non-immunogenic dPEG® crosslinkers. For more information about our dPEG® products, please see our "What is dPEG®?" page. Also, click here for answers to our most frequently asked questions.TFP Esters are Superior to NHS estersTFP esters are more stable in aqueous buffers than N-hydroxysuccinimidyl (NHS) esters. Moreover, TFP esters have higher reactivity with free amines than NHS esters.[3] NHS esters hydrolyze readily in water or aqueous buffer. As the pH increases, the hydrolysis rate of the NHS ester increases.[4] In 2017, a study by J. Wang, et al., on the performance of fluorophenyl esters concluded, "With regards to PEGylation, the TFP ester performed better than NHS ester."[5] These superior characteristics of TFP esters have been confirmed by in-house research at Quanta BioDesign.How to Use MAL-dPEG®12-TFP esterTFP esters react under the same conditions as NHS esters. However, the optimal pH range for TFP esters (7.5 – 8.0) is slightly higher than for NHS esters (7.0 – 7.5).5 Amide bond formation between the TFP-activated propionic acid group of MAL-dPEG®12-TFP ester and a free amine will be slightly slower at a sub-optimal pH compared to the reaction rate within the optimum pH range.The reaction of the maleimide end of MAL-dPEG®12-TFP ester, product number 10553, with a sulfhydryl proceeds best at pH 6.5 – 7.5. Conduct the conjugation at the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which can cause confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.[6] For details about maleimide-thiol reaction chemistry, please click here.Uses of MAL-dPEG®12-TFP esterMAL-dPEG®12-TFP ester, product number 10553, can be used the same way and in the same applications as the equivalent NHS esters. A 2019 study used PN10553 from Quanta BioDesign to synthesize pyrrolobenzodiazepine dimer antibody-drug conjugates with dual β-glucuronide and dipeptide triggers.[7] Other possible uses for this product include the following:
  • Coating nanoparticle surfaces;
  • Tethering antibodies to atomic force microscopy (AFM) probes;
  • Increasing the water solubility and hydrodynamic volume of hydrophobic biomolecules;
  • Building supramolecular constructs; and,
  • Conjugating the TFP ester end of the molecule a liposomal surface and then using the free maleimide end of the molecule to attach a small molecule drug, peptide, or antibody for targeted delivery of a diagnostic or therapeutic package.
How will you use this product?Bulk Scale Synthesis of MAL-dPEG®12-TFP ester is AvailableIf you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.Buy Now!Hydrophobic crosslinkers create more problems than they solve. Traditional disperse polymer PEG crosslinkers add unnecessary analytical complexity to conjugates that incorporate them.So, stop using inferior products!Start using single molecular weight dPEG® crosslinkers and discover the dPEG® difference. To get started, please click the "Add to Cart" button now to order MAL-dPEG®12-TFP ester, product number 10553.Application References:[1] Hermanson, G. T. Chapter 6, Heterobifunctional Crosslinkers. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 299–340, specifically page 300. Many scientists engaged in bioconjugation work consider Greg Hermanson's book to be the definitive reference on the subject. Click here now to read a review of Greg's book and to purchase it.[2] Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. In Bioconjugate Techniques, 3rd ed.; Academic Press: New York, NY, 2013; pp 787–838, specifically page 794.[3] Hermanson, G. T. Chapter 3, The Reactions of Bioconjugation. In Bioconjugate Techniques; Academic Press: New York, NY, 2013; pp 229–258, specifically page 239.[4] Ibid, page 234.[5] Wang, J.; Zhang, R.-Y.; Wang, Y.-C.; Chen, X.-Z.; Yin, X.-G.; Du, J.-J.; Lei, Z.; Xin, L.-M.; Gao, X.-F.; Liu, Z.; et al. Polyfluorophenyl Ester-Terminated Homobifunctional Cross-Linkers for Protein Conjugation. Synlett 2017, 28 (15), 1934–1938. https://doi.org/10.1055/s-0036-1590974.[6] Hermanson, G. T. Chapter 6, op. cit., page 304.[7] Gregson, S. J.; Barrett, A. M.; Patel, N. V.; Kang, G.-D.; Schiavone, D.; Sult, E.; Barry, C. S.; Vijayakrishnan, B.; Adams, L. R.; Masterson, L. A.; et al. Synthesis and Evaluation of Pyrrolobenzodiazepine Dimer Antibody-Drug Conjugates with Dual β-Glucuronide and Dipeptide Triggers. European Journal of Medicinal Chemistry 2019, 179, 591–607. https://doi.org/10.1016/j.ejmech.2019.06.044.
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