Liquid Handling System / Liquid Handler

Since liquid handling techniques have become an essential components of many laboratory research applications, a wide range of liquid handling system- also called liquid handling workstation, liquid handling robot or simply a liquid handler- have been introduced by laboratory equipment manufacturers in the market. They are an important biotechnology lab equipment apart from being a laboratory apparatus for chemical and biochemical laboratories. How do these liquid handlers work may be understood by knowing the basic liquid handling concepts.

Basic Liquid Handling Concepts

This section explains how laboratory liquid handling equipment work and what are the basic components of a liquid handler.

The liquid handling instruments obtain a volume of liquid from a source container. This is done with the help of pipettor which is one of the main component of a liquid handler. A pipettor of a liquid handling system performs two simple processes- Aspirating and Dispensing. The liquid is obtained by creating suction (aspirating). This liquid is then dispensed when it has been repositioned over the destination container by creating positive pressure. Aspirating can be explained as the process of bringing liquid into the tip, and dispensing means expelling that liquid from the tip. The liquid being transferred is generally called the sample fluid.

The sample fluid is generally held in the component of a liquid handler known as "Tip". Tips often resemble thin tubes or large hypodermic needles made from metal / plastic, or disposable conical pieces made from injection molded plastic. Many liquid handling systems have more than one tip which lets the device speed up the transfer of liquids by aspirating from or dispensing to multiple containers at the same time. Automated liquid handling systems mostly work with multiple tips. Majority of these automated liquid handling systems operate in the microliter to milliliter range of volumes.

Types of Liquid Handlers

Liquid handlers or precisely stated the automated liquid handling systems can be categorized on the basis of the types of pumps used in them; and on the basis of the size and number of channels provided into the instrument.

Liquid Handlers with Piston Pump

The liquid handling systems work on the principle of manipulation of pressures for liquid transfer. This is done through different methods that are based on different mechanical pump designs. The simplest of these liquid handling system pumps are the piston pumps. The piston fits snugly with an air-tight seal in a tube and when the piston is withdrawn, it creates negative pressure, which in turn creates suction, aspirating liquid into the tip. Advancing the piston creates positive pressure, which in turn forces fluid out of the tip or dispenses liquid. In automated liquid handling systems, piston pumps come in various forms. They can be air displacement systems where actual syringe pumps are directly connected to the working tip. They can also be liquid or hydraulic displacement systems where pumps are situated at a distance and connected through tubing. They can also be arrays of pistons joined to a plate that work within drilled holes in another structure.

Liquid Handlers with Vacuum or Air Pump

These types of liquid handlers use a pressure driven system where small air pumps or pressurized reservoirs create the vacuum for suction or pressure for dispense. The air pumps are generally mounted just above the tips. The advanced liquid handling systems include active valve and pressure sensing technology with advanced feedback-control algorithms that use the data collected from the pressure sensors to control the valves and pumps.

Liquid Handlers with Flow Through Pump

These types of liquid handling systems use flow through pumps. They can either be stand-alone devices or on piston based systems for bulk dispensing of reagent or diluting fluid. In this form, they are generally diaphragm, gear pumps or peristaltic pumps. A new type of liquid handling system utilizes a unique flow through gear pump that can reversibly pump highly accurate small volumes of liquid. For normal operation the fluid moved by the pump is a liquid working fluid which makes this system a type of liquid or hydraulic displacement device.

Single and Multi Channel Liquid Handlers

Automated Liquid handling systems can have a single channel or multiple channels that can go up to 1536 channels. These can be divided into three main types:

• Single channel liquid handlers;
• Multi-channel liquid handlers with small numbers of tips; and
• Multi-channel liquid handlers with large numbers of tips.

Single channel liquid handling systems though having great flexibility, can have throughput limitations because of its having only one channel. The multi-channel liquid handling systems are thus more popular and are manufactured on a large scale by different liquid handler manufacturers.

Small and Large Channel Liquid Handlers

The small liquid handling systems generally have 4, 8, 12 or 16 channels. On the other hand, the larger liquid handling workstations usually have 96, 384 or 1,536 channels. These number correspond to the matching numbers of the most common microplate formats i.e. 96, 384 and 1,536. These channels are made into a structure usually called a head with permanent spacing matching the spacing of the wells in the microplates.

Liquid Handler Manufacturers & Suppliers

We have a large database of laboratory equipment manufacturers and suppliers including liquid handling systems. Send Online Enquiry for all types of liquid handlers including automated liquid handlers and liquid handling robot for immediate quotes from genuine liquid handler suppliers.

Liquid Handling Robot

A liquid handling robot can be explained as automation of chemical or biochemical laboratories. In fact, an automated liquid handling system is called a liquid handling robot. This robot dispenses a selected quantity of reagent, samples or other liquid to a desired container. A simple liquid handling robot dispenses a volume of liquid from a motorized pipette or syringe. The more complicated ones can also manipulate the position of the dispensers and containers. With the advancements in liquid handling robotics, many of these robots come with additional laboratory devices integrated within them. These laboratory apparatus may include such devices as centrifuges, automated pipetting systems, microplate washers and microplate readers as well. These liquid handling robots can be called labor saving devices that offer precision sample preparation for high throughput screening/sequencing (HTC), liquid or powder weighing, sample preparation, and bio-assays of various kinds. Liquid handlers with robotic arms let the user to program the devices to manipulate external labware in order to extend the systems uses. Some liquid handling robot manufacturers even include additional features like programs to control start/stop functions and to choreograph sequential steps essential for chemical and biochemical assays and for injection options.

Liquid Handlers Applications

Liquid handlers were first introduced into biology laboratories in the 1980s. Now, the automated liquid handling robots are extensively used for various biological laboratory processes as well as in chemical and biochemical laboratories due to their many advantages. One of the main advantages of liquid handling systems is the ability of the laboratory to use the repeatability of automation to allow for miniaturizing assays from the milliliter range in to the microliter range. This lets laboratories save money in reagents and samples, as well as to increase throughput. Some of the applications of liquid handlers are listed as follows:

• PCR Preparation
• IC50 Plate Creation
• Compound Purification
• Metabolic Stability
• P450 Inhibition
• Solubility
• ELISA
• Cherry-picking
• Variable Input/Output
• Pipetting with tubes/vials
• Reformatting Plates
• Time-Course Studies
• Titration Studies
• Combinatorial Chemical Synthesis
• Plate Replication
• Screening Assays
• Cell-Based Assays

With their wide range of uses, automated liquid handlers now have extensive applications in laboratories involved in drug discovery, pharmaceutical development, pharmaceutical quality assurance, clinical reference and testing, forensics, biosecurity, food and agriculture development and safety, and materials science etc.

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