Life Sciences

Direct Titration - Unmatched Versatility, Down to the Nanoliter and Picoliter

January 4, 2024
min read
Debbie Bowers
Direct Titration - Unmatched Versatility, Down to the Nanoliter and Picoliter

When you want exact drug doses, think BioDot for your direct titration needs. BioDot’s Discrete Droplet Dispensing™ enables dispensing of an exact dose of drug - to all varieties of labware.

Serial Dilution

Traditionally, reaching small concentrations (nanoliter or lower) of a compound is performed via serial dilution. Serial dilution works by repeatedly diluting higher concentrations of a source compound with a dilution liquid, typically an aqueous buffer. The source compound is known as a “stock” and is generally kept in a high concentration to save storage space and allow for other compositions.

If we were to dilute 50 microliters (µL) of a stock compound into 100µL of buffer, the resulting mixture would be 150 µL of diluted stock in buffer. Since the compound constitutes 1/3 of the total volume of the combined parts, the dilution is 1:3. You can then repeat the process, taking 50µL of the 150µL total volume and diluting it with another 100µL of buffer. The original stock compound has now been diluted by an additional factor of 3. Since you have diluted by three, twice, you now have a dilution factor of 9 (three times three). You can repeat this step as many times as necessary to reach a desired concentration.

In serial dilution, the dilution factor does not typically change. For technicians, that means continuing to use the same dilution factor until you achieve your desired concentration. The final concentration you end up with can be summarized in the mathematical formula of [1/xn], where x is the dilution factor, and n is the number of times the dilution is repeated.

Direct Titration

Another method for dilution is directly dispensing the exact dose of compound desired into a set amount of buffer. This is referred to as direct titration. The advantage of direct titration is greater precision and fewer chances for errors. However, the task of dispensing minute amounts of stock needs to be done using a precise instrument.

For example, if a formula calls for 10 nanoliters (nL) of stock compound in 90µL of dilution buffer, you will need a tool or pipette capable of dispensing 10 nL. Ideally, you would have a tool that could dispense 10 nL without touching the dilution buffer (non-contact).

As with serial dilution, the dilution scheme may need to vary. An instrument that can work with samples as small as 10 nL and as great as 10 µL is… pardon the pun, indispensable.  Having an instrument capable of tuning a drop to be an exact dose of drug would be ideal for direct titration.

The BioDot Advantage

To be clear, there are ultra-low volume dispensers that can dispense in the range of 10nL to 10µL, but they sometimes do this by dispensing multiple drops to reach the desired dispense volume. Say a formula calls for a dispense volume of 1µL and the dispenser in your lab was only capable of dispensing a 10nL drop with a 0.05% margin of error. To create a 1µL volume, 1,000 drops of 10nL would need to be dispensed. The cumulative margin of error at 10nL each would be 65% (1.00051000=1.65). Compare this to a single drop at 1µL with the same margin of error (0.05%). A dispenser that can adjust to the precise dispense volume in a single drop for the application of direct titration is ideal.

Additionally, a formula may call for dilutions as small as picoliters (pL), levels normally only achievable by serial dilution. You may be wondering if a non-contact instrument exists that can dispense in pLs, nLs, and µLs?  The answer is yes.  BioDot offers entry-level platforms capable of dispensing ultra-low volumes at an entry price of ~$50,000.

Our platforms do not limit the source or destination labware and do not require the use of our proprietary consumables. Our customers can use whatever labware they wish – be it slides, plates, microfluidics, trays, and more.

Because our proprietary dispensing technology is not limited to dispensing compounds in DMSO (dimethyl sulfoxide), our platforms can be used with most varieties of liquids, including biologicals such as DNA, proteins, cells, and more. Biological treatment types are a key area of research, and being able to analyze their effectiveness and dosage is important. A universal system capable of working with more than compounds in DMSO saves a laboratory money on invested capital and reduces learning times for researchers.

For those who are unfamiliar with BioDot’s proprietary technology, we are not new to precision dispensing. Our company was founded in 1994 and many of our early years were focused on dispensing technologies, specifically on dispensing nanoliters. While most scientists were focused on microliters and SBS plate standardization, we were pioneering how to push beyond micro volumes to nano volumes. We were investigating displacements without touching a surface and looking beyond dispensing into plates. Early applications for our technology were in lateral flow, biochips, and biosensors. These are applications where ultra-low volumes, dispensed quickly at very precise locations, is a necessity.

BioDot has supported discoveries in veterinary sciences, agriculture, pharmaceuticals, diagnostics, and consumer products for decades. Now, billions of Point-of-Care devices later, we hope to show life science scientists the tools available for their application in the serial dilution/direct titration area.

Think beyond the bounds of microplates, compounds in DMSO, microliters, and $250,000 solutions. Talk to us about Discrete Droplet Dispensing™ and we will introduce you to a new tool for science, that won’t break your budget and will enable new breakthroughs.

About the Author

Debbie Bowers, MBA, BS, General Manager

Debbie has 26 years in supporting global Life Science customers through automation consultation, applications development and first in class customer care. She is an industrial engineer with an MBA and an emphasis in Global Marketing, as well as holding a certification in Contract Law. Debbie has holistic familiarity with all scientific application areas with knowledge of global best practices used in laboratories around the world.

Debbie joined BioDot in 2020. From 2017 to 2020, as President and CCO, Debbie led the commercial strategy for BioSoft Integrators. BioSoft offers Laboratory Information Management Systems (LIMS) to life science, clinical and manufacturing operation laboratories & is the preferred provider of High Performance Computing (HPC) solutions for global PacBio NGS customers. Through Debbie's leadership from 2014 to 2017 as VP of Robotic Operations at Hamilton Robotics, her team of 250+ outperformed Industry Growth Targets YoY in selling automated liquid handling systems, while vaulting industry partnerships with the top 20 Life Science innovators, and launched 20+ new products to clinical and RUO customers. 2013/14, Bowers was VP of Business Development at Invetech, a Danaher company, who specialized in product development for clinical diagnostics, life science and consumer product companies like Haemonetics, Coca Cola and Bio-Rad.  From 2000 - 2012, Debbie acquired in-depth knowledge in all areas of liquid handling automation, detection, automated sample storage and retrieval systems and the consumables and modules required to automate complete workflows for life science applications in her many roles at Tecan US.  At Tecan, she was responsible for sales, marketing, applications, custom solutions, product development and worked with every facet of customer type and scientific application. Early engineering, project management and technical sales roles provided Debbie with expertise in micro and macro filtration when working for Pall Gelman Sciences and Baker Hughes Process Equipment Company.