Barcode tagging of human oocytes and embryos to prevent mix-ups in assisted reproduction technologies

IVF laboratory management through workflow-based RFID tag witnessing and real-time information entry

BACKGROUND

Dual-person inspection in IVF laboratories cannot fully avoid mix-ups or embryo transfer errors, and data transcription or entry is time-consuming and redundant, often leading to delays in completing medical records.

METHODS

This study introduced a workflow-based RFID tag witnessing and real-time information entry platform for addressing these challenges. To assess its potential in reducing mix-ups, we conducted a simulation experiment in semen preparation to analyze its error correction rate. Additionally, we evaluated its impact on work efficiency, specifically in operation and data entry. Furthermore, we compared the cycle costs between paper labels and RFID tags. Finally, we retrospectively analyzed clinical outcomes of 20,424 oocyte retrieval cycles and 15,785 frozen embryo transfer cycles, which were divided into paper label and RFID tag groups.

RESULTS

The study revealed that comparing to paper labels, RFID tag witnessing corrected 100% of tag errors, didn't affect gamete/embryo operations, and notably shorten the time of entering data, but the cycle cost of RFID tags was significantly higher. However, no significant differences were observed in fertilization, embryo quality, blastocyst rates, clinical pregnancy, and live birth rates between two groups.

CONCLUSIONS

RFID tag witnessing doesn't negatively impact gamete/embryo operation, embryo quality and pregnancy outcomes, but it potentially reduces the risk of mix-ups or errors. Despite highly increased cost, integrating RFID tag witnessing with real-time information entry can remarkably decrease the data entry time, substantially improving the work efficiency. This workflow-based management platform also enhances operational safety, ensures medical informational integrity, and boosts embryologist's confidence.

Considerations on staffing levels for a modern assisted reproductive laboratory

The duties recently performed in the embryology laboratory have deeply increased compared to those realized a couple of decades ago. Currently, procedures include conventional in vitro fertilization (IVF) and ICSI techniques, or processing of surgically retrieved sperm, embryo culture and time-lapse monitoring, blastocyst culture, as well as trophectoderm biopsy for preimplantation genetic testing and cryopreservation. These techniques require not only time, but also high knowledge level and acutely concentration by the embryologist team. The existing data indicate that an IVF laboratory need to have adequate staffing levels to perform the required daily duties, and to work in optimal conditions that are critical to assure a high quality service, as well as avoiding incidents and to provide the best outcomes. As a result, IVF clinics have invested in human resources, but there is still a large discrepancy between IVF centres on the number of embryologists employed. Currently there is no golden standard on the human resource requirements for assisted reproductive technology procedures; therefore, in this review paper we aim to provide arguments to take into account to determine the embryology staffing requirements in an embryology laboratory to assure optimal safety and efficiency of operations.

Catastrophic Human Error in Assisted Reproductive Technologies: A Systematic Review

OBJECTIVE

Assisted reproductive technologies (ARTs) are complex processes with multiple and diverse opportunities for human error. Errors in ART are thought to be rare, but can have devastating consequences for patients and their offspring. The objectives of this article are to review known cases of human error in the ART laboratory and suggest preventative strategies.

METHODS

We performed a systematic review of the literature in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines using PubMed and Google Scholar databases. Studies were eligible for inclusion if they involved known cases of unintentional human error in the ART laboratory. Only full-text articles in English were included. References of the resulted studies were considered for inclusion.

RESULTS

A total of 420 articles were screened and 37 articles were selected for inclusion. These largely included case reports and reviews in the medical and legal literature. Twenty-two adverse events due to human error in the ART laboratory were identified. Eight of these adverse events were the result of the insemination with the wrong sperm, 6 errors lead to the transfer of the wrong embryo, 3 lead to an error in preimplantation genetic testing, and 5 adverse events lead to the failure of gamete and embryo cryostorage.

CONCLUSIONS

Since the advent of ART, there have been reports of catastrophic events occurring secondary to human error in the laboratory to include incidents of unintended parentage, and have resulted in the loss of embryos and gametes through cryostorage failure. Proposed solutions include the stringent implementation and adherence to safety protocols, adequate laboratory staffing and training, and novel methods for specimen labeling and tracking. Of utmost importance is having knowledge of these errors and the ability to determine cause so that future events can be prevented.

Integrating magnetic capabilities to intracellular chips for cell trapping

Current microtechnologies have shown plenty of room inside a living cell for silicon chips. Microchips as barcodes, biochemical sensors, mechanical sensors and even electrical devices have been internalized into living cells without interfering their cell viability. However, these technologies lack from the ability to trap and preconcentrate cells in a specific region, which are prerequisites for cell separation, purification and posterior studies with enhanced sensitivity. Magnetic manipulation of microobjects, which allows a non-contacting method, has become an attractive and promising technique at small scales. Here, we show intracellular Ni-based chips with magnetic capabilities to allow cell enrichment. As a proof of concept of the potential to integrate multiple functionalities on a single device of this technique, we combine coding and magnetic manipulation capabilities in a single device. Devices were found to be internalized by HeLa cells without interfering in their viability. We demonstrated the tagging of a subpopulation of cells and their subsequent magnetic trapping with internalized barcodes subjected to a force up to 2.57 pN (for magnet-cells distance of 4.9 mm). The work opens the venue for future intracellular chips that integrate multiple functionalities with the magnetic manipulation of cells.

Application of femtosecond laser microsurgery in assisted reproductive technologies for preimplantation embryo tagging

Femtosecond laser pulses were applied for precise alphanumeric code engraving on the zona pellucida (ZP) of mouse zygotes for individual embryo marking and their identification. The optimal range of laser pulse energies required for safe ZP microsurgery has been determined. ZP was marked with codes in three different planes to simplify the process of embryo identification. No decrease in developmental rates and no morphological changes of embryos post laser-assisted engraving have been observed. ZP thickness of embryos post laser-assisted code engraving has been shown to differ significantly from that of control group embryos at the hatching stage. Due to moderate ZP thinning as compared to its initial width at 0.5 dpc (days post coitum), readability of the code degrades slightly and it still remains recognizable even at hatching stage. Our results demonstrate that application of femtosecond laser radiation could be an effective approach for noninvasive direct embryo tagging, enabling embryo identification for the whole period of preimplantation development.

Femtosecond laser is effective tool for zona pellucida engraving and tagging of preimplantation mammalian embryos

PURPOSE

Our purpose was to study whether application of femtosecond laser pulses for alphanumeric code marking in the volume of zona pellucida (ZP) could be effective and reliable approach for direct tagging of preimplantation embryos.

METHODS

Femtosecond laser pulses (wavelength of 514 nm, pulse duration of 280 fs, repetition rate of 2.5 kHz, pulse energy of 20 nJ) were applied for precise alphanumeric code engraving on the ZP of mouse embryos at the zygote stage for individual embryo marking and their accurate identification. Embryo quality assessment every 24 h post laser-assisted marking as well as immunofluorescence staining (for ICM/TE cell number ratio calculation) were performed.

RESULTS

Initial experiments have started with embryo marking in a single equatorial plane. The codes engraved could be clearly recognized until the thinning of the ZP prior to hatching. Since embryo may change its orientation during the ART cycle, multi-plane code engraving seems to be more practical for simplifying the process of code searching and embryo identification. We have marked the ZP in three planes, and no decrease in developmental rates as well as no morphological changes of embryos post laser-assisted engraving have been observed as compared to control group embryos.

CONCLUSIONS

Our results demonstrate the suitability of femtosecond laser as a novel tool for noninvasive embryo tagging, enabling embryo identification from day 0.5 post coitum to at least early blastocyst stage. Thus, the versatility and the potential use of femtosecond lasers in the field of developmental biology and assisted reproduction have been shown.

Tagging of individual embryos with electronic p-Chips

Collecting information about biochemical processes occurring inside a single cell or embryo is traditionally done either using fluorescent dyes with microscopy or via microelectrode voltage-clamp techniques. This paper demonstrates that a more direct method - transmission of information using an electronic chip implanted in an embryo - is feasible. A light-activated microtransponder with dimensions 250 μm × 250 μm × 100 μm (a "p-Chip") was implanted into a blastula-stage frog (Xenopus laevis) embryo. To implant the chip, a small slit is made in the blastocoel roof with an electrolytically-sharpened tungsten needle, and the p-Chip is inserted using fine forceps. The chip is activated when illuminated by a 60 mW focused laser beam, which causes the p-Chip to send its numeric ID to a nearby receiver. At no time during signal transmission does a wire or other type of object come in contact with or penetrate the epidermal layer covering the p-Chip. The embryo survives the procedure, extruding the chip after approximately 3 h. The method shows promise for studies including voltage potential, pH and other parameters.

Failure mode and effects analysis of witnessing protocols for ensuring traceability during PGD/PGS cycles

Preimplantation genetic diagnosis and aneuploidy testing (PGD/PGS) use is constantly growing in IVF, and embryo/biopsy traceability during the additional laboratory procedures needed is pivotal. An electronic witnessing system (EWS), which showed a significant value in decreasing mismatch occurrence and increasing detection possibilities during standard care IVF, still does not guarantee the same level of efficiency during PGD/PGS cycles. Specifically, EWS cannot follow single embryos throughout the procedure. This is however critical when an unambiguous diagnosis corresponds to each embryo. Failure Mode and Effects Analysis (FMEA) is a proactive method generally adopted to define tools ensuring safety along a procedure. Due to the implementation of a large quantitative PCR (qPCR)-based blastocyst stage PGD/PGS programme in our centre, and to evaluate the potential procedural risks, a FMEA was performed in September 2014. Forty-four failure modes were identified, among which six were given a moderate risk priority number (>15) (RPN; product of estimated occurrence, severity and detection). Specific corrective measures were then introduced and implemented, and a second evaluation performed six months later. The meticulous and careful application of such measures allowed the risks to be decreased along the whole protocol, by reducing their estimated occurrence and/or increasing detection possibilities.

Traceability of human sperm samples by direct tagging with polysilicon microbarcodes

The increasing number of patients undergoing assisted reproductive technology (ART) treatments and of cycles performed in fertility centres has led to some traceability errors. Although the incidence of mismatching errors is extremely low, any error is unacceptable, therefore different strategies have been developed to further minimize these errors, such as manual double-witnessing or electronic witnessing systems. More recently, our group developed a direct tagging method consisting of attaching microbarcodes directly to the zona pellucida of human oocytes/embryos. Here, this method is taken a step further by using these microbarcodes to tag human semen samples, demonstrating that the barcodes are not toxic and do not interfere in the selection of motile spermatozoa nor in the cryopreservation of the sperm samples. In addition, when this tagging system was applied to an animal model (rabbit), pregnancy rate and kitten viability were not affected.

Silicon-nanowire based attachment of silicon chips for mouse embryo labelling

The adhesion of small silicon chips to cells has many potential applications as direct interconnection of the cells to the external world can be accomplished. Hence, although some typical applications of silicon nanowires integrated into microsystems are focused on achieving a cell-on-a-chip strategy, we are interested in obtaining chip-on-a-cell systems. This paper reports the design, technological development and characterization of polysilicon barcodes featuring silicon nanowires as nanoscale attachment to identify and track living mouse embryos during their in vitro development. The chips are attached to the outer surface of the Zona Pellucida, the cover that surrounds oocytes and embryos, to avoid the direct contact between the chip and the embryo cell membrane. Two attachment methodologies, rolling and pushpin, which allow two entirely different levels of applied forces to attach the chips to living embryos, are evaluated. The former consists of rolling the mouse embryos over one barcode with the silicon nanowires facing upwards, while in the latter, the barcode is pushed against the embryo with a micropipette. The effect on in vitro embryo development and the retention rate related to the calculated applied forces are stated. Field emission scanning electron microscopy inspection, which allowed high-resolution imaging, also confirms the physical attachment of the nanowires with some of them piercing or wrapped by the Zona Pellucida and revealed extraordinary bent silicon nanowires.

Development of a security system for assisted reproductive technology (ART)

PURPOSE

In the field of assisted reproductive technology (ART), medical accidents can result in serious legal and social consequences. This study was conducted to develop a security system (called IVF-guardian; IG) that could prevent mismatching or mix-ups in ART.

MATERIALS AND METHODS

A software program was developed in collaboration with outside computer programmers. A quick response (QR) code was used to identify the patients, gametes and embryos in a format that was printed on a label. There was a possibility that embryo development could be affected by volatile organic components (VOC) in the printing material and adhesive material in the label paper. Further, LED light was used as the light source to recognize the QR code. Using mouse embryos, the effects of the label paper and LED light were examined. The stability of IG was assessed when applied in clinical practice after developing the system. A total of 104 cycles formed the study group, and 82 cycles (from patients who did not want to use IG because of safety concerns and lack of confidence in the security system) to which IG was not applied comprised the control group.

RESULTS

Many of the label paper samples were toxic to mouse embryo development. We selected a particular label paper (P touch label) that did not affect mouse embryo development. The LED lights were non-toxic to the development of the mouse embryos under any experimental conditions. There were no differences in the clinical pregnancy rates between the IG-applied group and the control group (40/104 = 38.5 % and 30/82 = 36.6 %, respectively).

CONCLUSIONS

The application of IG in clinical practice did not affect human embryo development or clinical outcomes. The use of IG reduces the misspelling of patient names. Using IG, there was a disadvantage in that each treatment step became more complicated, but the medical staff improved and became sufficiently confident in ART to offset this disadvantage. Patients who received treatment using the IG system also went through a somewhat tedious process, but there were no complaints. These patients gained further confidence in the practitioners over the course of treatment.