Your construct is not necessarily impossible. It may just need a different approach. Let our scientists assess it before you write it off.
When Standard Providers Say No
If you have ever submitted a sequence and received a cancellation weeks later, an unexplained complexity surcharge, or a polite email explaining that synthesis is not possible at this time, you are not alone.
This is a documented and common failure mode across the gene synthesis industry. Silicon-based synthesis platforms have hard sequence constraints. High-volume providers deprioritize difficult orders in favour of throughput.
The outcome for researchers: wasted weeks, stalled experiments, and projects that miss grant or publication timelines.
BioCat assesses every complex sequence manually before quoting. In most cases we can give you a feasibility assessment and quote within one business day. If your sequence falls into a category that needs extended evaluation, we will tell you that upfront rather than accepting your order and cancelling it later.
The BioCat Difference
We are a specialist distributor, not a high-volume synthesis factory. That distinction shapes how we handle every order.
Transparent pricing
Standard sequences start from EUR 110. Complex constructs are quoted individually after a free feasibility review. You will never receive a bill that does not match your quote.
Expert sequence review
Before we quote a complex construct, a scientist evaluates your sequence. We flag risks, suggest design improvements where relevant, and give you an honest timeline. If we cannot make it, we tell you immediately.
European ordering advantage
BioCat is based in Germany. Orders are placed and managed locally: straightforward EU invoicing, fast regional shipping, no import customs delays, and biosecurity compliance handled within EU regulatory frameworks.
Scientific partnership
We offer free codon optimization, sequence advice, and direct access to technical support. For labs that have been burned by black-box providers, working with BioCat feels different.
What We Handle
BioCat gene synthesis is set up to work with sequences that fall outside standard parameters:
High GC content
We synthesize sequences with GC content up to approximately 80%. Constructs exceeding this threshold are assessed case by case. We will always give you the honest position on your specific sequence, not a generic range.
Tandem repeats and low-complexity regions
Repetitive elements create assembly and verification challenges. We evaluate these manually and, where direct synthesis is not the optimal route, propose validated alternatives including gene splitting or codon-adjusted redesign.
Large constructs
We handle constructs well beyond 5 kb. Length-based complexity is factored into your quote transparently, with no post-order surcharges.
Non-standard expression contexts
Unusual codon usage profiles for yeast, mammalian, insect, or plant expression are handled with organism-specific codon optimization. This service is available free of charge on request.
What Happens When You Submit a Complex Sequence
Our process is designed to reduce the uncertainty that makes complex gene synthesis frustrating.
You submit your sequence through our online portal or by email
A PhD scientist reviews the sequence, typically within one business day
You receive a feasibility assessment: can we make it, at what price, and in what timeframe
If synthesis is not possible as submitted, we propose alternative strategies before you commit
Once you approve the quote, synthesis begins. No charges are added after this point
If synthesis cannot be completed, there is no charge. Any exceptions are communicated in your quote before you commit. We never add any additional fees without our customers' approval.
Sequence Advice Before You Order
For sequences at the edge of what is synthesizable, small adjustments can make the difference between a successful synthesis and a failed attempt. Our scientists can advise on:
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Codon adjustment strategies to reduce secondary structure formation
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Gene splitting approaches for constructs that exceed single-synthesis length limits
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Restriction site removal or addition that does not disrupt function
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Tag integration and reading-frame verification before synthesis begins
This advice is provided free of charge as part of the quoting process. Please note that this is sequence-level guidance: we review your gene construct and flag synthesis risks. Full plasmid design is outside the scope of this service.
Frequently Asked Questions
We do not apply a hard cut-off. Sequences with GC content up to approximately 80% are routinely synthesized. Above that threshold, feasibility depends on the specific sequence context. Submit your sequence and a scientist will assess it, typically within one business day.
In most cases, yes. Tandem repeats increase synthesis complexity and cost, and this will be reflected in your quote. Where direct synthesis is not the optimal approach, we will propose alternatives such as gene splitting or sequence adjustment before you commit.
We review every complex sequence before quoting rather than accepting orders and cancelling them weeks later. In some cases, synthesis is not feasible and we will tell you that upfront with an explanation and proposed alternatives. We aim to give you a clear position before you commit, not after.
Yes. We routinely synthesize sequences with GC content up to approximately 80%, and in some cases beyond that. Highly challenging sequences may incur a higher quoted price due to increased process complexity, and this will be communicated clearly before the order is confirmed.
If synthesis cannot be completed, there is no charge. Any exceptions are communicated in your quote before the order is confirmed. We never add any additional fees without our customers' approval.
Submit it. Our scientists evaluate sequences based on GC content, repeat density, predicted secondary structures, and length. You will receive a written assessment, typically within one business day. There is no charge for this review.