Antibody conjugates have become a major highlight among biological agents for targeted
therapeutic studies, and immunoassay or detection applications. Bio-Synthesis offers
custom antibody bioconjugation services using monoclonal antibody or polyclonal
antibody through chemical conjugation with other biomolecules. This includes the
conjugation of antibodies and their fragments with biologically active molecules
such as nucleic acids, oligonucleotides and their analogs, peptides, proteins, or
with any molecular group that adds valuable properties—i.e. radionucleotides, drugs,
toxins, enzymes, metal chelates, fluorophores, haptens, and others.
Our unique and unrivaled expertise in research and development offers you the best
quality antibody bioconjugates in the industry. From custom antibody development
to modification and bioconjugation, all are produced in-house at Bio-Synthesis.
Each antibody-biopolymer conjugate is meticulously monitored according to our stringent
quality assurance and quality control standards.
The immunoconjugate for therapeutic purpose is undergoing an outburst of activities
for research and development. This novel approach to drug delivery could lead to
safer methods of reducing dosage, and increasing efficacy without causing harmful
side effects. Monoclonal antibodies can be utilized for drug or isotope deliveries;
however, the biological functions of monoclonal antibodies are often sensitive to
subtle variations in structure. Hence, the chemical aspects of preparing, purifying,
and characterizing these conjugates must be carefully considered.
Bio-Synthesis's custom antibody conjugation services include experimental design,
and method development for the preparation of conjugates to
be used in life science research, diagnostic and drug discovery.
Over the decades, we have accumulated a continually growing portfolio of antibody
modification and conjugation services.
If you can't find what you want, contact our National Customer Service Center at
800.220.0627, or contact us online with your detailed project descriptions.
Sample Submission Requirements:
Modification or conjugation of whole immunoglobulin fraction, secondary antibodies,
polyclonal and monoclonal antibodies should be affinity purified prior to undergoing
bioconjugation to prevent nonspecific interaction. Bio-Synthesis also assist in
providing affinity chromatography services using the corresponding immobilized antigen
or immunoglobulin binding protein (e.g. protein A may be employed.) Client must supply
Bio-Synthesis an antibody quality check documentation.
While traditional antibody conjugation takes advantage of lysine ϵ-amino , N-terminal α-amine groups or carboxylate groups due to its abundance in antibody, the conjugation procedure that utilize these groups often changes the overall pI of the antibody and leads to higher nonspecific binding. In addition, this random cross-linking within antibody often obscuring the binding sites and may produce partially active or inactive antibody conjugates that may not bind to the antigen.
Bio-Synthesis offers site-specific antibody conjugation services based on the unique conjugation strategy developed at Bio-Synthesis. Drugs, toxins, oligo DNA, RNA, or peptide, small molecules can be conjugated to an antibody at a specific site away from the antigen binding site. Site-specific cross-linking results in high retention antigen binding activity within the ensuing conjugate.
Single or few predictable sites labeling allow better manufacturing reproducibility
specific binding (efficient and safe drugs).
NHS Ester-Maleimide-Mediated Conjugates
Reductive Amination-Mediated Conjugation
Conjugation Using Antibody Fragments
It is often advantageous to use antibody fragments in the preparation of antibody bioconjugates. This is done by selective antibody fragmentation using enzymatic digestion of intact immunoglobulins into lower molecular weight molecules that still able to recognize and bind antigen. Conjugation of antibody fragment with enzyme molecules can result in ELISA reagents that possess better characteristics than corresponding conjugates prepared with intact antibody. Such antibody fragment conjugates display less interference with various Fc binding proteins and also less immunogenicity, more facile membrane penetration for immunohistochemical staining techniques, and lower nonspecific binding to surfaces or membranes, resulting in increased signal-to-noise ratios. We provides services such as:
Service Specification: Starting quantity: 5 mgs, 2 mgs of antibody for initial pilot conjugation prior production
is required for a thorough optimization, and method development of purification and analysis. Although we have been successful with as little as 200 micrograms in some cases. We provide few test run for customer to test. Once agree on the test conjugates within one week. Bio-Synthesis will proceed scale up production. After conjugation, a standard desalting, or purification, a small percent
of heterogeneous products containing single or multi-site conjugate per molecule
Material: Antibody and antibody fragments: Fab, F(ab')2, Half antibody,
Procedure: All custom synthesis of biomolecule, modification or
bioconjugation services is manufactured under strict quality control processes.
Analytical HPLC and MS analyses are performed in every development cycle. Final
target conjugates must first be isolated from excess or unreacted reagent. In many
cases, simple dialysis removes unreacted reagent from the reaction solution (if
the protein/antibody is significantly larger (>3-fold) than the modifying or
coupling reagent). Additional purification such as stirred cell filtration, tangential
flow filtration (TFF), or gel filtration chromatography may also be used to either
remove excess reagent or to isolate and characterize the cross-linked product. Reagents
that are similar in size or larger than the antibody (mostly protein and other biological
molecules) may require other purification techniques such as affinity chromatography,
ion-exchange chromatography, and hydrophobic interaction chromatography.
Cross-linked target molecule may then be further characterized by biochemical or
biophysical techniques with an additional fee. Once the product has been purified,
it may be subject to many different types of studies including spectroscopic (MALDI-TOF,
ESI, LC-MS Fluorescence), electrophoresis, immunochemical biochemical, enzymatical
analysis. QC (quality control) and QA (quality assurance) procedures are also followed
independently to offer you double guarantee for the highest quality possible of
every delivered conjugates. Moreover, our dedicated technical account managers will
guide your project through every step of the process and constantly keep you informed
of the latest project progress.
Deliverable: 7-10 weeks, conjugates will deliver in buffer solution
close to physiological pH, such as phosphate buffered saline (PBS), are generally
Whereas we can chemically link the intended components of a conjugated molecule;
there exist the possibility that the binding sites/active sites of the protein can
be altered/modified, partially or completely, independent of the stoichiometry used. Sometimes
this activity loss is caused by physically blocking the antigen binding sites during
conjugation or by conformational changes in the complement-determining regions.
Some proteins/antibodies are just too labile to undergo chemical modification reactions,
regardless of the coupling methods used.
Bio-Synthesis can only guarantee the structure of our conjugates but not the suitability
to specific biological applications
If you can't find the antibody conjugation service you need, please contact us online with your detail project
Price: Price varies based on the project specifications. Our service includes materials
and labor for conjugation only! Price does not include the cost of biopolymer synthesis or purchase from a commerical vendor
and, if deemed necessary, biopolymer modification to introduce additional functional
groups, extra linkers, spacers. Please contact us for a quote.
Discount: 15 % discount pricing applies to additional conjugates ordered at the same
Visit our literature vaults for more references and citings.
For us to better understand your customized project, please complete our Bioconjugation Service Questionnaire. The more our chemists understand your project needs, the more accurate feedback we will be able to provide you. Providing us with your project details will enable us to recommend the best reagents to use for your own project. The most useful and readily available tools for bioconjugation projects are cross-linking reagents. A large number of cross-linkers, also known as bifunctional reagents, have been developed. There are several ways to classify the cross-linkers, such as the type of reactive group, hydrophobicity or hydrophilicity, and the length of the spacer between reactive groups. Other factors to consider are whether the two reactive groups are the same or different (for example, heterobifunctional or homobifunctional reagents), whether the spacer is cleavable, and whether the reagents are membrane permeable or impermeable. The most accessible and abundant reactive groups in proteins are the ϵ-amino groups of lysine. Therefore, a large number of the most common cross-linkers are amino selective reagents, such as imidoesters, sulfo-N-hydroxysuccinimide esters, and N-hydroxysuccinimide esters. Due to the high reactivity of the thiol group with N-ethylmaleimide, iodoacetate and a-halocarbonyl compounds, new cross-linkers have been developed that contain maleimide and a-carbonyl moieties. Usually, N-alkylmaleimides are more stable than their N-aryl counterparts.
In addition to the reactive groups on the cross-linkers, a wide variety of connectors and spacer arms have also been developed. The nature of the spacer arm, and also the length, play an important role in the functionality. Longer spacer arms are generally more effective when coupling large proteins or those with sterically protected reactive side-chains. Other important considerations are the hydrophobicity, hydrophilicity, and the conformational flexibility. Long aliphatic chains generally fold on themselves when in an aqueous environment, which makes the actual distance spanned by such linker arms less than expected. Instead, spacers that contain more rigid structures (for example, aromatic groups or cycloalkanes) should be used. These structures, however, tend to be very hydrophobic which could significantly decrease the solubility of the modified molecules or even modify some of their properties. In such cases, it is recommended to choose a spacer that contains an alkylether (PEO) chain. Bio-Synthesis offers several cross-linkers with PEO chains, such as thiol-binding homobifunctional reagents, heterobifunctional based, and their derivatives.
Once the project scope has collected, we will provide an appropriate quotation within 3-5 days. Orders can be placed with either a PO (Purchase Order) or credit card. We accept POs and major credit cards ( ). Your credit card will be billed under 'Bio-Synthesis, Inc.' Click here to download our credit reference form. For international orders, we must apply the full charge at the time of the order is placed. In the unlikely event that any given order cannot be filled, our guarantee will take the form of a full refund.