An in-line microfluidic blood sampling interface between patients and saline infusion systems.
ABSTRACT This work seeks to extend the utility of microfluidics to conventional blood sampling aperati. Daily medical care of hospitalized patients demands repeated needle punctures or interfacing with a catheter to collect blood samples. Large, research grade systems can autonomously sample blood from laboratory animals; however, a disposable aperatus that can be used to repeatedly sample blood from hospitalized patients does not exist. We have designed, fabricated and demonstrated a 3-layered rigid polymer microfluidic blood sampling device with integrated polymer pinch valves for placement in-line between a patient and a saline infusion system. The blood sampler we designed seeks to mitigate sample cross contamination, reduce risks of microbial contamination associated with invasive blood sampling and improve technical ease of blood sampling. Clinical laboratory tests and microfluidic devices for rapid point-of-care-testing (POCT) of patient samples require human sampling procedures for collection of a patient sample at defined time points. The microfluidic sampling device is designed ultimately to be backwards compatible with existing clinical saline infusion protocols and function as a universal front-end blood sampling unit for the variety of microfluidic lab chips and POCT devices.
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ABSTRACT: Jugular catheters were inserted in nine male rats under general isofluorane anesthesia and the catheters were connected to a commercially available computerized blood sampling device (Accusampler). Blood samples (150 microl) were collected every 4 h during the first 24 h after surgery and every 12 h during the following 72 h until 94 h after surgery, when the animals were killed. All fecal pellets were collected at blood sampling. Serum corticosterone and fecal concentrations of immunoreactive corticosterone metabolites and immunoglobulin A (IgA) were quantified by ELISAs. In blood, high corticosterone concentrations (>200 ng/ml) were recorded in the first samples obtained after surgery, but the concentrations decreased steadily during the day and became cyclical, showing a diurnal variation with high levels during evenings and low levels in the mornings. The automatic blood sampling itself did not result in recordable increases in serum corticosterone concentrations. The time delay between the presence of elevated corticosterone levels in blood and in feces was approximately 12 h. Fecal immunoreactive corticosterone metabolite levels remained elevated during the 94 h study period after surgery. The fecal concentrations of IgA showed substantial between-animal variation and decreased non-significantly after the surgery. Like serum corticosterone, fecal IgA showed a diurnal variation in amounts excreted, in this case with high values in the morning and low values in the evening. The concentrations of fecal corticosterone and IgA were negatively correlated in samples obtained before surgery but no correlation existed after surgery. This indicates that fecal immunoreactive corticosterone metabolites, but not IgA, constitute a good marker of acute stress. For immunoreactive corticosterone metabolites as well as for IgA, the concentration in feces correlated well with total excretion, making single fecal samplings usable as a measure of total secretion.Journal of Endocrinology 02/2004; 180(1):145-53. · 4.06 Impact Factor
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ABSTRACT: Quantitative microPET imaging provides the capability of performing biochemical and physiological investigations. The collection of multiple blood samples over time is necessary for quantitative analysis. The procedure is challenging because the amount of blood volume is small in rats and mice. To overcome this issue, an automatic blood sampling system was developed using a novel microfluidic chip design to take serial blood samples (<0.25 muL per sample; 18 blood samples in current design) at precise times from rats and mice. In this work, we utilize a National Instruments DAQPad 6507 digital output computer interface to control the sampling on the chip via mini-pneumatic valves. The system provides a user-friendly GUI programmed by LabVIEW to setup the sampling information, which includes mouse ID, tracer selection and sampling volume and time sequences. It can be easily reconfigured to utilize new microfluidic chip designs as well as changes in the sampling protocol. Real-time sampling status and the output of sampling information is continually displayed. Our initial implementation of this design can automatically collect ~0.185 muL blood samples within less than 2 second intervals from a small rodent.Nuclear Science Symposium Conference Record, 2006. IEEE; 12/2006
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ABSTRACT: A major problem in preclinical drug development where blood sampling from small animals is a routine practice is the time and labor involved in the serial sampling of small blood volumes from small animals such as rats for the duration of pharmacokinetic/pharmacodynamic (PK/PD) studies. The traditional method of manually drawing blood from the animal requires the animal to be anesthetized or restrained with some device, both of which cause stress to the animal. An automated blood sampler (ABS) was developed to simultaneously collect blood and brain microdialysate samples at preprogrammed time points from awake and freely moving animals. The samples are delivered to fraction collectors and stored at 4 degrees C until use. The lost blood volume during collection is replaced with sterile saline to prevent fluid loss from the animal. In addition, the system is capable of collecting urine and feces for metabolism studies and monitoring the animal activity for behavioral studies. In the present study, blood samples were collected for 24 h after dosing rats orally with a 5 mg/kg dose of olanzapine (OLAN). Brain dialysates were collected for the same duration from a microdialysis probe implanted in the striatum. The pharmacokinetic parameters, obtained after an oral dose, are in good agreement with reported values in literature. The pharmacodynamic information obtained from brain dialysates data show that OLAN elevates the concentration of dopamine (DA) in the brain and remains in the brain even after it is cleared from the plasma. The ABS described here is a very useful tool in drug development to accelerate the pace of preclinical in vivo studies and to simultaneously provide pharmacodynamic and physiological information.Journal of Pharmacological and Toxicological Methods 01/2004; 49(1):57-64. · 2.15 Impact Factor