Strategies to Maintain Sample Integrity Using a Liquid-Filled Automated Liquid-Handling System with Fixed Pipetting Tips

An Update on Current Trend in Sample Preparation Automation in Bioanalysis: strategies, Challenges and Future Direction

Automation in sample preparation improves accuracy, productivity, and precision in bioanalysis. Moreover, it reduces resource consumption for repetitive procedures. Automated sample analysis allows uninterrupted handling of large volumes of biological samples originating from preclinical and clinical studies. Automation significantly helps in management of complex testing methods where generation of large volumes of data is required for process monitoring. Compared to traditional sample preparation processes, automated procedures reduce associated expenses and manual error, facilitate laboratory transfers, enhance data quality, and better protect the health of analysts. Automated sample preparation techniques based on robotics potentially increase the throughput of bioanalytical laboratories. Robotic liquid handler, an automated sample preparation system built on a robotic technique ensures optimal laboratory output while saving expensive solvents, manpower, and time. Nowadays, most of the traditional extraction processes are being automated using several formats of online techniques. This review covered most of the automated sample preparation techniques reported till date, which accelerated and simplified the sample preparation procedure for bioanalytical sample analysis. This article critically analyzed different developmental aspects of automated sample preparation techniques based on robotics as well as conventional sample preparation methods that are accelerated using automated technologies.

Ferrowax microvalves for fully automated serial dilution on centrifugal microfluidic platforms

We herein describe a centrifugal microfluidic system to accomplish a fully automated serial dilution. The liquid flow on the disc was regulated by utilizing ferrowax microvalves systematically integrated into the channels within specially designed metering structures. By opening the differently positioned microvalves through irradiation of IR laser to allow metering, the same amount of diluent was serially eluted to the dilution chamber from the same diluent chamber. After dilution, the diluted samples were automatically delivered to the respective final product chambers by appropriately opening or closing the microvalves in the connecting channels, followed by rotating the disc. Based on this unique design principle, six consecutive two-fold and 10-fold dilutions were successfully achieved, yielding excellent accuracy in a wide dynamic range up to six orders of magnitude. Very importantly, the overall serial dilution process, including the diluent addition, mixing, and product transfer steps, was completed very rapidly within 5 min, due to the minimized procedures enabled by the automated actuation of the ferrowax microvalves at the rationally designed positions. We expect our centrifugal microfluidic system would serve as a powerful elemental tool to realize fully automated diagnostic microsystems involving the serial dilution process.

Integration of Acoustic Liquid Handling into Quantitative Analysis of Biological Matrix Samples

Acoustic liquid handlers deliver small volumes (nL-µL) of multiple fluid types with accuracy and dynamic viscosity profiling. They are widely used in the pharmaceutical industry with applications extending from high-throughput screening in compound management to gene expression sequencing, genomic and epigenetic assays, and cell-based assays. The capability of the Echo to transfer small volumes of multiple types of fluids could benefit bioanalysis assays by minimization of sample volume and by simplifying dilution procedures by direct dilution. In this study, we evaluated the Labcyte Echo 525 liquid handler for its ability to deliver small volumes of sample preparations in biological matrix (plasma and serum) and to assess the feasibility of integration of the Echo with three types of bioanalytical assay platforms: microplate enzyme-linked immunosorbent assay, Gyrolab immunoassay, and liquid chromatography with tandem mass spectrometry. The results demonstrated acceptable consistency of dispensed plasma samples from multiple lots and species by the Echo. Equivalent assay performance demonstrated between the Echo and manual liquid procedures indicated great potential for the integration of the Echo with the bioanalytical assay, which allows the successful implementation of microsampling strategies in drug discovery and development.

Low expression of vascular endothelial growth factor and high serum level of cyclic guanine monophosphate as the risk factors of femoral head osteonecrosis in alcohol-exposed Wistar rat

PURPOSE

Severe damage to the femoral head in patients with osteonecrosis has a high impact on morbidity. Despite early diagnosis, the treatment outcome is still unsatisfactory. This study aimed to explore the expression of vascular endothelial growth factor (VEGF) and cyclic guanine monophosphate (cGMP) serum level as the risk factors of femoral head osteonecrosis in alcohol-exposed Wistar rats.

METHODS

This was an experimental study using randomized post-test only control group design, with samples using 10-14 weeks Wistar male rats. Rats were then divided into 6 groups: 3 groups without intervention, and 3 groups with intervention using 40% alcohol given perorally. Each one group from intervention and control group was euthanized by the end of the week for 3 consecutive weeks. Proximal femurs were examined under microscope for osteonecrosis, immunohistochemically for VEGF, and blood serum for cGMP levels.

RESULTS

VEGF expression in the femoral head of alcohol-exposed Wistar rats was lower than those not exposed to alcohol (p < 0.005). Blood serum cGMP levels of alcohol-exposed Wistar rats were higher than those not exposed to alcohol (p < 0.005). The number of necrotic osteocytes in the femoral head of Wistar rats exposed to alcohol was greater than those not exposed to alcohol (p < 0.005). There are significant differences between VEGF, cGMP levels, and number of necrotic osteocytes in the control group and treatment at 1st, 2nd^, and 3rd week (p < 0.005).

CONCLUSIONS

Based on the result of this study, VEGF and cGMP may be considered as diagnostic biomarkers for alcohol-induced femoral head osteonecrosis.

A Low-Cost, Accurate, and High-Precision Fluid Dispensing System for Microscale Application

We present here the development of a low-cost, accurate, and precise fluid dispensing system. It can be used with peristaltic or any other pump to improve the flow characteristics. The dispensing system has a range of 1 to 100 µL with accuracy of ~99.5% and standard deviation at ~150 nL over the entire range. The system developed does not depend on the accuracy or precision of the driving pump; therefore, any positive displacement pump can be used to get similar accuracy and precision, which gives an opportunity to reduce the cost of the system. The dispensing system does not require periodic calibration and can also be miniaturized for microfluidic application. Although primarily designed for aqueous liquid, it can be extended for different nonconductive liquids as well with modifications. The unit is further used for near real-time measurement of lactate from microdialysate. The individual components can easily be made disposable or sterilized for use in biomedical applications.

Automated Gravimetric Calibration to Optimize the Accuracy and Precision of TECAN Freedom EVO Liquid Handler

High-throughput screening technologies are increasingly integrated into the formulation development process of biopharmaceuticals. The performance of liquid handling systems is dependent on the ability to deliver accurate and precise volumes of specific reagents to ensure process quality. We have developed an automated gravimetric calibration procedure to adjust the accuracy and evaluate the precision of the TECAN Freedom EVO liquid handling system. Volumes from 3 to 900 µL using calibrated syringes and fixed tips were evaluated with various solutions, including aluminum hydroxide and phosphate adjuvants, β-casein, sucrose, sodium chloride, and phosphate-buffered saline. The methodology to set up liquid class pipetting parameters for each solution was to split the process in three steps: (1) screening of predefined liquid class, including different pipetting parameters; (2) adjustment of accuracy parameters based on a calibration curve; and (3) confirmation of the adjustment. The run of appropriate pipetting scripts, data acquisition, and reports until the creation of a new liquid class in EVOware was fully automated. The calibration and confirmation of the robotic system was simple, efficient, and precise and could accelerate data acquisition for a wide range of biopharmaceutical applications.

Instrument Quality Control

Well-defined quality control (QC) processes are used to determine whether a certain procedure or action conforms to a widely accepted standard and/or set of guidelines, and are important components of any laboratory quality assurance program (Popa-Burke et al., J Biomol Screen 14: 1017-1030, 2009). In this chapter, we describe QC procedures useful for monitoring the accuracy and precision of laboratory instrumentation, most notably automated liquid dispensers. Two techniques, gravimetric QC and photometric QC, are highlighted in this chapter. When used together, these simple techniques provide a robust process for evaluating liquid handler accuracy and precision, and critically underpin high-quality research programs.

Current advances and strategies towards fully automated sample preparation for regulated LC–MS/MS bioanalysis

Robotic liquid handlers (RLHs) have been widely used in automated sample preparation for liquid chromatography–tandem mass spectrometry (LC–MS/MS) bioanalysis. Automated sample preparation for regulated bioanalysis offers significantly higher assay efficiency, better data quality and potential bioanalytical cost-savings. For RLHs that are used for regulated bioanalysis, there are additional requirements, including 21 CFR Part 11 compliance, software validation, system qualification, calibration verification and proper maintenance. This article reviews recent advances in automated sample preparation for regulated bioanalysis in the last 5 years. Specifically, it covers the following aspects: regulated bioanalysis requirements, recent advances in automation hardware and software development, sample extraction workflow simplification, strategies towards fully automated sample extraction, and best practices in automated sample preparation for regulated bioanalysis.

Overview of liquid handling instrumentation for high-throughput screening applications

Liquid handling in the laboratory has unique challenges specific to the types of research being performed. The devices employed for purposes of performing liquid handling can be broken down into three general categories: bulk reagent dispensers, transfer devices, and plate washers. An overview of these types of liquid handlers, as well as common features and relevance to high-throughput applications, are discussed in this article. Important topics such as sterility, ease of use, cost, and instrument design advantages and disadvantages are also covered. Curr. Protoc. Chem Biol. 1:43-54. © 2009 by John Wiley & Sons, Inc.

Dispersion serial dilution methods using the gradient diluter device

A solute aspirated into a prefilled tube of diluent undergoes a dilution effect known as dispersion. Traditionally the effects of dispersion have been considered a negative consequence of using liquid-filled fixed-tip liquid handlers. We present a novel device and technique that utilizes the effects of dispersion to the benefit of making dilutions. The device known as the Gradient Diluter extends the dilution range of practical serial dilutions to six orders of magnitude in final volumes as low as 10 μL. Presented are the device, dispersion methods, and validation tests using fluorescence detection of sulforhodamine and the high-performance liquid chromatography/ultraviolet detection of furosemide. In addition, a T-cell inhibition assay of a relevant downstream protein is used to demonstrate IC(50) curves made with the Gradient Diluter compare favorably with those generated by hand.