Fluorescence-Activated Droplet Sorting (FADS) Technology

CD Biosynsis utilizes advanced Fluorescence-Activated Droplet Sorting (FADS) Technology to offer ultra-high-throughput screening and isolation of single cells, microbial strains, or enzyme variants encapsulated within picoliter-volume droplets. FADS is a cutting-edge microfluidic platform that combines the high-speed screening capabilities of traditional flow cytometry with the compartmentalization benefits of microdroplets, enabling the analysis and sorting of millions of individual events per hour. This technology is essential for directed evolution, single-cell analysis (e.g., transcriptomics), high-throughput drug screening, and the isolation of rare or high-performing biocatalysts. We provide tailored FADS assay development, ensuring accurate quantification and precise sorting based on fluorescence intensity or enzyme activity within the droplet environment.

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Ultra-High-Throughput Screening and Single-Cell Isolation

FADS works by encapsulating individual cells or molecular reactions into monodisperse microdroplets, where the reaction or activity is linked to a fluorescence signal. Each droplet acts as an isolated microreactor, preventing cross-contamination and allowing for quantitative analysis of the encapsulated entity. The droplets are then passed through a laser-interrogation point. If the measured fluorescence signal exceeds a defined threshold, the droplet is electrically charged and precisely deflected into a collection tube. This technology achieves sorting rates far exceeding conventional plate-based methods (up to 10,000 events per second), making it indispensable for screening large mutant libraries (e.g., >$10^7$ variants) in directed evolution campaigns and isolating rare cellular populations.

FADS Technology Workflow

A systematic process for ultra-high-throughput screening and isolation.

Assay & Droplet Generation

Ultra-High-Throughput Screening

Fluorescence-Activated Sorting

Recovery & Downstream Analysis

Probe Design: Develop a fluorescent reporter or substrate that correlates with the desired function (e.g., enzyme activity).

Encapsulation: Encapsulate single cells or reactions (e.g., $10^7$ library members) into picoliter water-in-oil droplets.

Incubation: Allow sufficient time for the reaction/expression to occur within the isolated droplets.

Screening: Pass millions of droplets per hour through the microfluidic chip's laser-detection point.

Threshold Setting: Define the fluorescence intensity threshold based on control populations.

Sorting: Apply an electric field to precisely deflect and collect the droplets that meet the desired fluorescence criteria (e.g., top 0.01% performers).

Breaking Emulsion: Chemically or physically break the water-in-oil emulsion to release the sorted cells/molecules.
Viability & Purity Check: Confirm the viability (for cells) and purity of the sorted population.
Downstream Analysis: Prepare the recovered target for sequencing, culturing, or further characterization.

Massive Throughput and Single-Cell Resolution

Ultra-High Throughput

Ability to screen and sort millions to billions of events in hours, accelerating directed evolution campaigns.

Picoliter Compartmentalization

Each droplet acts as an isolated microreactor, allowing single-cell and single-molecule resolution without cross-contamination.

Selection of Rare Events

Highly sensitive detection capable of isolating variants with an improvement rate as low as 1 in $10^6$ or $10^7$.

Tailored Assay Development

Expertise in developing and validating fluorescence-linked enzyme activity assays compatible with microdroplets.

Client Testimonials on FADS Technology

"The FADS screening allowed us to screen a library of $10^8$ enzyme variants in less than a week and successfully isolate the top 0.001% performers, drastically accelerating our evolution project."

Dr. Kai Zimmer, Directed Evolution Lead

"We used their FADS service for single-cell transcriptomics prep on a rare immune cell population. The purity and cell viability post-sorting were exceptionally high."

Ms. Isabella Rossi, Cell and Gene Therapy Researcher

"The team developed a custom fluorogenic assay for our non-native enzyme activity, enabling us to screen millions of synthetic biology strains efficiently using FADS."

Mr. Samuel Jones, Synthetic Biology Program Manager

FAQs about Fluorescence-Activated Droplet Sorting (FADS)

Still have questions?

What is the main advantage of FADS over traditional FACS?

FADS offers ultra-high throughput (sorting >10,000 events/second) and picoliter-scale compartmentalization, which allows the analysis of enzyme activity and molecular reactions within isolated microreactors, making it ideal for large-scale directed evolution libraries.

How do you ensure only one cell is in each droplet?

Droplet generation is controlled using microfluidics and carefully adjusted flow rates. By keeping the concentration of cells low (typically < 1 cell per 10 droplets), we ensure that the vast majority of cells are encapsulated as single entities following Poisson statistics.

Can FADS be used to screen for enzyme activity?

Yes. The core application is screening for activity. We use fluorogenic substrates that, upon cleavage by the encapsulated enzyme, produce a fluorescent product. The intensity of the fluorescence directly correlates with the enzyme's specific activity.

What is the typical sorting rate and recovery rate?

FADS can screen and sort up to 10,000 droplets per second. The purity of the sorted population is typically >95%, and the recovery rate of cells/molecules from the final collection can be optimized to be very high, depending on the downstream application.

How much does Metabolic Engineering services cost?

The cost of Metabolic Engineering services depends on the project scope, complexity of the target compound, the host organism chosen, and the required yield optimization. We provide customized quotes after a detailed discussion of your specific research objectives.

Do your engineered strains meet regulatory standards?

We adhere to high quality control standards in all strain construction and optimization processes. While we do not handle final regulatory approval, our detailed documentation and compliance with best laboratory practices ensure your engineered strains are prepared for necessary regulatory filings (e.g., GRAS, FDA).

What to look for when selecting the best gene editing service?

We provide various gene editing services such as CRISPR-sgRNA library generation, stable transformation cell line generation, gene knockout cell line generation, and gene point mutation cell line generation. Users are free to select the type of service that suits their research.

Does gene editing allow customisability?

Yes, we offer very customised gene editing solutions such as AAV vector capsid directed evolution, mRNA vector gene delivery, library creation, promoter evolution and screening, etc.

What is the process for keeping data private and confidential?

We adhere to the data privacy policy completely, and all customer data and experimental data are kept confidential.

Fluorescence-Activated Droplet Sorting (FADS) Technology

Ultra-High-Throughput Screening and Single-Cell Isolation

Customizable FADS Screening and Sorting Modules

Choose Your Sorting Mode

Select the required FADS service based on the target of your screening campaign:

Key Application Areas

FADS is ideal for applications requiring massive parallel screening and analysis:

Assay and Recovery Optimization

Essential steps for successful FADS screening and downstream analysis:

FADS Technology Workflow

Massive Throughput and Single-Cell Resolution

Client Testimonials on FADS Technology

FAQs about Fluorescence-Activated Droplet Sorting (FADS)