Journal of Laboratory Automation

Since the beginning of this decade the use of automated or robotic-systems for analytical purposes has decreased rapidely. Starting from the analysis of agriculturing products or medical samples, these instruments are now more and more common in the pharmaceutical industry. The systems are used for R&D purposes mainly in the area of combinatorial chemistry to analyze the huge amount of synthesis products in the biomedical labs and in chemical-physical laboratories of Quality Contol Units. Extensive stability studies, which have to be perfomed for new drug applications, and the release testing of medicinal products with a very high manufacturing batch-rate per year need highly effective analytical methods. Thus, Byk Gulden has introduced two automated systems based on Zymark products (TPWII and MultiDose), for the stability tests of an enteric-coated tablet. The number of batches, pack types and storage conditions (total number of samples: appr. 40 for the 3- and 6-months timepoints), for this stability study was required automation of the most time consuming test methods for purity, assay and dissolution of the tablets, because of the tight schedule for timepoints in the first year of storage (in general: two weeks). In order to have these automated systems in place for routine testing in a very short time, the method transfer from the manual procedure as well as the optimization and validation work (MTOV), were done completely by the supplier, Zymark. The other system, which is a customer designed robotic system built also by Zymark, is used for the release testing of an x-ray contrast medium with a very high batch-rate per year (approxmimately four batches per day that have to be analyzed). This enormous testing frequency is hardly to be realized by manual methods. Experiences with an already existent robotic systems has shown that the laboratory flow-through times are 30 to 50% decreased compared to manual testing.

Development of drug candidates, which modulate cytokine responses or metabolic pathways by targeting gene expression, requires analytical systems that measure specific messenger RNAs rapidly and accurately and that can be adapted to high throughput screening operations. Chromagen's High Performance Signal Amplification (HPSA), system, a DNA probe hybridization method, has been enhanced to measure two different mRNA targets simultaneously in the same micro-plate well. Multi-target testing using HPSA takes advantage of a family of low molecular weight fluorescent dyes with large quantum yields, which exhibit distinct excitation and emission wavelengths. A two-target model system using cultured human THP-1 cells examined IL-1β mRNA induction in response to bacterial lipopolysaccharide (LPS) exposure and also monitored intrinsic β-actin mRNA as a housekeeping gene transcript. An oligonucleotide DNA probe complementary to IL-1β RNA was labeled with a reporter ligand while a β-actin DNA probe was linked directly to an enzyme. Sample mRNA was captured onto the surface of micro-plate wells and hybridized to both DNA probes. After removing non-hybridized probe, a second enzyme conjugate that specifically recognizes the IL-1β DNA probe reporter ligand was allowed to bind. The two enzyme systems were distinguished by using substrates labeled with different fluorescent tags (one for IL-1β and the other for β-actin). Resolution of the two fluorescent products was carried out with Chromagen's high-sensitivity, photon-counting fluorometer. This system was capable of detecting synthetic RNA targets for IL-1β and β-actin in the attomole range. Authentic β-actin mRNA was measured in 50,000 uninduced cells and this signal could be specifically competed away by addition of excess unlabeled β-actin probe during hybridization. A time course of IL-1β mRNA induction in THP-1 cells by LPS revealed that peak induction occurred after 2–3 hours. The β-actin mRNA level showed an initial decrease, but remained relatively constant throughout the remaining time points. Results obtained with the dual detection format paralleled those generated when each target was measured separately in its single-target gene expression assay. Chromagen's HPSA two-target system not only augments screening information, but also saves testing time and conserves reagents. The potential of this system is being explored with different gene targets of therapeutic value and other housekeeping genes.

IGEN's ORIGEN® technology, which is based on electrochemiluminescence, has been adopted by a number of research and bioanalytical laboratories who have recognized its exquisite sensitivity, high precision, wide dynamic range, and flexibility in formatting a wide variety of applications. IGEN's M-SERIES™ marks the introduction of the second generation of detection systems employing the ORIGEN technology specifically repackaged to address the needs of the high throughput laboratories involved in drug discovery. Assays are formatted without wash steps. Users realize the high performance of a heterogeneous technology with the convenience of a homogeneous format. The M-SERIES platform can address enzymatic assays (kinases, proteases, helicases, etc.), receptor-ligand or protein-protein assays, immunoassays, quantitation of nucleic acids, as well as other applications. Recent assay formats will be explored in detail.

Sol-gel chemistry provides a novel production route for ceramics and composites that have a variety of applications in medicine, biology, and biochemistry. Advantages of sol-gel-derived materials in these applications include simple, low temperature production routes that are capable of achieving temperature, chemical, and radiation-inert porous materials with a wide range of structural and microstructural properties. Furthermore, sol-gel-derived materials display remarkable compatibility with biomacromolecules and are conveniently functionalized with a variety of coupling agents. The properties of these materials and their present and potential applications in medicine and biology are reviewed.

Low output impedance composite pH sensors were constructed by direct attachment of an impedance converter to laboratory purpose combined pH glass electrodes. The signal was transmitted in analog form by unshielded electric cable. The performance of new and aged composite pH sensors was determined by the multiple-point calibration method. In case of new electrodes, the slope and the response time, as well as the reproducibility, were insignificantly influenced by the converter attached (the mean slope values calculated for the six electrode group studied were 57.80 mV/pH for unmodified electrodes and 57.97 mV/pH for modified electrodes). The electrode response was not affected by the presence of various electromagnetic noise sources or by the input impedance value of the measuring instrument. The slope and the response time of aged sensors were considerably improved using the impedance converter. The response time decreased from about 150–180 sec to about 30 sec and the average slope value increased from 54.94 mV/pH, calculated for unmodified electrodes, to 56.96 mV/pH, for modified electrodes.