In The News
Bio-Synthesis offers conjugation of dendritic nanomaterial (dendrimer or dendron)
to siRNA, DNA, RNA, peptides, drugs to form a supramolecular structures. These nano-sized,
radially symmetric molecules has well-defined, homogeneous and monodisperse structure
consisting of tree-like arms or branches. Dendrimeric constructs can function as
multivalent bioconjugation scaffolds, for enhnacement of signals in assays, to solubilize
hydrophobic molecules in aqueous environments by interal entrapment, to functionalize
surfaces and particles for conjugation, as transfection agents for cells, to create
targeted therapeutic constructs for the treatment of disease, as carriers of affinity
ligands, and as dditive for other polymer mixtures.
Relying on a state-of-the art chemial biology facilities and over 30 years of combine
experience in providing high quality dendritic biopolymer complexes, each custom
project is metriculously monitored according to Bio-Synthesis's stringent quality
assurance and quality control standard that are fully backed up by an bioanalytical
Price varies based on the proejct specifications. Our service includes materials
and labor for conjugation only! Price does not include the cost of biopolymer synthesis
and, if deemed necessary, biopolymer modification to introduce additional functional
groups, extra linkers, spacers. Please contact us for a quote.
Coupling of preactivated small molecule and biomolecule
with chemical reactive groups such as amine, thiol, carboxylate, hydroxyl, aldehyde
and ketone, active hydrogen through use of varous cross linkers.
After standard desalting, or purification,
a small percent of heterogeneous products containing single or multi-site conjugate
per molecule may exist.
After labeling , final conjugates must first be isolated
from excess or unreacted reagent by gel filtration or dialysis with a matrix having
an exclusion limit appropriate to accommodate the size of the molecules being separated.
Cross-linked target molecule may then be further characterized by gel electrophoresis.
It may be subject to additional analyses with an addtional fee. This including spectroscopic
(MALDI-TOF, ESI, LC-MS Fluorescence), electrophoresis, immunochemical biochemical,
enzymatical analysis, TLC. 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.
To obtain further information regarding custom dendrimer or dendron bioconjugation,
contact our National Customer Services Center at 800.227.0627 or
contact us online with each inquiry to assist in meeting customer specifications.
Dendrimers are discrete, highly branched, monodispersed polymers with three disctinct
structureal features: a central core surface functionalities and branching units
that link the two. Plain and mixed oligonucleotide dendrimers can be synthesized
using novel doubling and trebling phosphoramidite synthons.1,2 Dendrimers offer
the following advantages. Incorporation of label using γ-32P-ATP and polynucleotide
kinase increases in proportion to the number of 5’-ends. Fluorescent signal also
increases in proportion to the number of 5’-ends, if spacers are incorporated between
the labels and the ends of the branches. When using a dendrimeric oligonucleotide
as a PCR primer, the strand bearing the dendrimer is resistant to degradation by
T7 Gene 6 exonuclease making it easy to convert the double-stranded product of the
PCR to a multiply labelled, single-stranded probe. Enhanced stability of DNA dendrimers
makes them useful as building blocks for the ‘bottom up’ approach to nano-assembly.
These features also suggest applications in DNA chip technology when higher temperatures
are required, for example, to melt secondary structure in the target.
Can't find type of service you need? don't worry, as you can see we've provided
myriad of bioconjugation services as described in our service portfolios and much
more, just contact our National Customer Service Center at 800.220.0627
contact us online with your detail project descriptions, in most case,
we can accommodate your bioconguateion needs!
Peptide dendrimers are radial or wedge-like branched macromolecules consisting of
a peptidyl branching core and/or covalently attached surface functional units. The
multimeric nature of these constructs, the unambiguous composition and ease of production
make this type of dendrimer well suited to various biotechnological and biochemical
applications. Diagnostic and biochemical uses of peptide dendrimers in four active
areas of research:
Peptide dendrimers vary from low molecular weight species of 2 kDa to large protein-like
constructs 100 kDa. The size and complexity of the inliidual dendrimers are determined
by two factors, the number of layers of branching units (often referred to as the
generation number) and the surface supporting the terminal functional groups which
can be large peptides or proteins of substantial size. Typically, peptide dendrimers
have generation numbers between 2 and 32. Similarto other dendrimers, synthesis
of peptide dendrimers is tightly controlled with products of consistent size, architecture
Peptide dendrimers can be liided into three types. The first are grafted peptide
dendrimers. These are conventional dendrimers with either unnatural amino acids
or organic groups as the branching core and peptide or proteins attached as surface
functional groups. Of the three, the grafted peptide dendrimer is the largest in
terms of size because they generally contain high generation numbers of branching
cores. In contrast, peptide dendrimers of the second type are essentially branching
polyamino acids. Consequently, they tend to be the smallest by size with the core
consisting of natural amino acids and the terminal amino acids acting as surface
functional groups. The third type consisting of mostly peptides has been traditionally
known as peptide dendrimers. In this group, with MAPs as the most well known example,
the core consists of amino acids and the surface functional groups are also peptidyl
antigenic (MAP) peptide dendrimers are branched polymers with peptides attached
centrally to a dendritic lysine arms or core matrix and a surface of peptide chanins
attached to the core matrix. They are synthesized as defined dendritic structures
using two methods 1) direct standard solid-phase (Fmoc) chemistry; 2) indirect approach
in which peptide an dcore matrix are synthesized separately and conjugated by several
ligation methods. Their molecular weights increase geometrically as a function of
generation branching of monomers. Usually, two to sixteen peptidyl branches of the
same or different sequences are used to form a peptide dendrimer, resulting three
dimensional molecule which has a high molar ratio of peptide antigen to core molecule,
and therefore, does not require the use of a carrier protein to induce an antibody
response. These high molar ratio and dense packing of multiple copies of the antigenic
epitope in a MAP has been use to promote immunoresponse. In addition to the applications
in immunology, examples in the literature have applied MAPs in areas such as inhibitors,
artificial proteins, affinity purifications, and intracellular transport.
The MAP, which is chemically defined and homogeneous, was first intended as a means
for overcoming the limitations of the conventional method for producing anti-peptide
antibodies. In the conventional approach, the peptide antigen is conjugated to a
known large protein, or synthetic polymer carrier, to form a peptide-carrier conjugate.
Although this strategy has been used successfully in eliciting animal antibodies,
it has several inherent limitations. First, only a small portion of peptide antigen
is represented in the whole conjugate; second, there is chemical ambiguity in the
antigen composition and structure; third, irrelevant epitopes and antibodies may
be produced; and finally, carrier toxicity and carrier-induced epitope suppression
may occur. The MAP systems have been used successfully to produce both polyclonal
and monoclonal antibodies that specifically recognize native proteins. They have
also been used to produce sera that have a significantly higher titer of antibodies
than sera with antibodies against the same peptides conjugated to the commonly used
carrier protein keyhole limpet hemocyanin (KLH; Tam, 1988).
grafted peptide dendrimer with unnatural amino acids and organic poly(amidoamine),
or PAMAM core, is perhaps the most well known dendrimer. The core of PAMAM is a
diamine (commonly ethylenediamine), which is reacted with methyl acrylate , and
then another ethylenediamine to make the generation-0 (G-0) PAMAM. Successive reactions
create higher generations, which tend to have different properties. Lower generations
can be thought of as flexible molecules with no appreciable inner regions, while
medium sized (G-3 or G-4) do have internal space that is essentially separated from
the outer shell of the dendrimer. Very large (G-7 and greater) dendrimers can be
thought of more like solid particles with very dense surfaces due to the structure
of their outer shell. Peptide can be attached through the functional group on the
surface of PAMAM dendrimers which gives rise to many potential applications.
Bio-Synthesis offer Peptide-PAMAM dendrimer synthesis with various core types and
generations. contact our National Customer Service Center at 800.220.0627 or
contact us online with your detail project descriptions, in most case, we can accommodate
your bioconguateion needs!
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. Provide us with your project details will enable to us to recommend the best reagents to use for your 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 aremore 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 and length of the spacer arm 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.
Within 3-5 days upon receiving your project scope, we will provide you an appropriate quotation. An order can be placed with PO (Purchase Order) or major credit cards ( ). Your credit card will be billed under Bio-Synthesis, Inc.