Dynamic placenta-on-a-chip model for fetal risk assessment of nanoparticles intended to treat pregnancy-associated diseases

Identification of micro- and nanoplastic particles in postnatal sprague-dawley rat offspring after maternal inhalation exposure throughout gestation

Micro-nanoplastic particulates (MNPs) have been identified in both indoor and outdoor environments. From these real-world exposures, MNPs have been identified in human fluids and organ tissues, including the placenta and breastmilk. Laboratory studies have identified MNPs are capable of crossing the placental barrier and depositing in fetal tissues; however, it remained unclear if MNPs persist in offspring tissues after birth. Six pregnant Sprague-Dawley rats were divided equally into two groups: control and exposed to polyamide-12 (PA-12) MNP aerosols (11.46 ± 3.78 mg/m3) over an average of 4.35 h ± 0.39 for 10 non-consecutive days between gestational day (GD) 6 - GD 19, in our custom rodent exposure chamber, allowing for whole-body inhalation. Two-weeks after delivery in-house, offspring tissues (i.e. lung, liver, kidney, heart, brain) from 1 male and 1 female pup per litter were fixed in 4 % paraformaldehyde, sectioned, stained with hematoxylin and eosin, and assessed using hyperspectral dark-field microscopy. PA-12 MNPs were identified in all offspring tissues of the exposed dams. No MNPs were visualized in control tissues. These findings have important implications for human MNPs translocation, deposition, maternal/fetal health, and the developmental origins of health and disease. Further research is warranted to quantify MNPs mass deposition, biological accumulation, and systemic toxicity.

Beyond 2D: Novel biomaterial approaches for modeling the placenta

This review considers fully three-dimensional biomaterial environments of varying complexity as these pertain to research on the placenta. The developments in placental cell sources are first considered, along with the corresponding maternal cells with which the trophoblast interact. We consider biomaterial sources, including hybrid and composite biomaterials. Properties and characterization of biomaterials are discussed in the context of material design for specific placental applications. The development of increasingly complicated three-dimensional structures includes examples of advanced fabrication methods such as microfluidic device fabrication and 3D bioprinting, as utilized in a placenta context. The review finishes with a discussion of the potential for in vitro, three-dimensional placenta research to address health disparities and sexual dimorphism, especially in light of the exciting recent changes in the regulatory environment for in vitro devices.

Non-Viral RNA Delivery During Pregnancy: Opportunities and Challenges

During pregnancy, the risk of maternal and fetal adversities increases due to physiological changes, genetic predispositions, environmental factors, and infections. Unfortunately, treatment options are severely limited because many essential interventions are unsafe, inaccessible, or lacking in sufficient scientific data to support their use. One potential solution to this challenge may lie in emerging RNA therapeutics for gene therapy, protein replacement, maternal vaccination, fetal gene editing, and other prenatal treatment applications. In this review, the current landscape of RNA platforms and non-viral RNA delivery technologies that are under active development for administration during pregnancy is explored. Advancements of pregnancy-specific RNA drugs against SARS-CoV-2, Zika, influenza, preeclampsia, and for in-utero gene editing are discussed. Finally, this study highlights bottlenecks that are impeding translation efforts of RNA therapies, including the lack of accurate cell-based and animal models of human pregnancy and concerns related to toxicity and immunogenicity during pregnancy. Overcoming these challenges will facilitate the rapid development of this new class of pregnancy-safe drugs.

The Application of Engineered Nanomaterials in Perinatal Therapeutics

Pregnancy is a vulnerable life stage for the mother and developing fetus. Because of this dual concern, approved therapeutic options for pre-existing conditions or pregnancy-induced pathologies, placental deformities, or fetal concerns are extremely limited. These cases often leave patients and clinicians having to choose between maternal health and fetal development. Recent advancements in nanomedicine and nanotherapeutic devices have made the development of perinatal therapeutics an attractive objective. However, perinatal medicine requires a multifaceted approach given the interactions between maternal, placental, and fetal physiology. Maternal-fetal interactions are centralized to the placenta, a specialized transient barrier organ, to allow for nutrient and waste exchange. Perinatal nanotherapeutics must be designed for placental avoidance or uptake. In this review, pregnancy-related conditions, experimental models, and modes of drug delivery during pregnancy are discussed.

Rational Design of Nanomedicine for Placental Disorders: Birthing a New Era in Women's Reproductive Health

The placenta is a transient organ that forms during pregnancy and acts as a biological barrier, mediating exchange between maternal and fetal circulation. Placental disorders, such as preeclampsia, fetal growth restriction, placenta accreta spectrum, and gestational trophoblastic disease, originate in dysfunctional placental development during pregnancy and can lead to severe complications for both the mother and fetus. Unfortunately, treatment options for these disorders are severely lacking. Challenges in designing therapeutics for use during pregnancy involve selectively delivering payloads to the placenta while protecting the fetus from potential toxic side effects. Nanomedicine holds great promise in overcoming these barriers; the versatile and modular nature of nanocarriers, including prolonged circulation times, intracellular delivery, and organ-specific targeting, can control how therapeutics interact with the placenta. In this review, nanomedicine strategies are discussed to treat and diagnose placental disorders with an emphasis on understanding the unique pathophysiology behind each of these diseases. Finally, prior study of the pathophysiologic mechanisms underlying these placental disorders has revealed novel disease targets. These targets are highlighted here to motivate the rational design of precision nanocarriers to improve therapeutic options for placental disorders.

Organ-on-a-chip: future of female reproductive pathophysiological models

The female reproductive system comprises the internal and external genitalia, which communicate through intricate endocrine pathways. Besides secreting hormones that maintain the female secondary sexual characteristics, it also produces follicles and offspring. However, the in vitro systems have been very limited in recapitulating the specific anatomy and pathophysiology of women. Organ-on-a-chip technology, based on microfluidics, can better simulate the cellular microenvironment in vivo, opening a new field for the basic and clinical research of female reproductive system diseases. This technology can not only reconstruct the organ structure but also emulate the organ function as much as possible. The precisely controlled fluidic microenvironment provided by microfluidics vividly mimics the complex endocrine hormone crosstalk among various organs of the female reproductive system, making it a powerful preclinical tool and the future of pathophysiological models of the female reproductive system. Here, we review the research on the application of organ-on-a-chip platforms in the female reproductive systems, focusing on the latest progress in developing models that reproduce the physiological functions or disease features of female reproductive organs and tissues, and highlighting the challenges and future directions in this field.

Improved anti-diabetic and anticancer activities of green synthesized CuO nanoparticles derived from Tabernaemontana divaricate leaf extract

Copper oxide nanoparticles (CuO NPs) are among the most commonly employed nanoparticle materials owing to their antibacterial qualities, although their primary mechanism of action (MOA) is still not completely understood. CuO NPs are synthesized in this study using leaf extract of Tabernaemontana divaricate (TDCO3), and they are then analyzed using XRD, FT-IR, SEM, and EDX analysis. The zone of inhibition of TDCO3 NPs against both gram-positive (G+) B. subtilis and gram-negative (G-) K. pneumoniae bacteria was 34 mm and 33 mm, respectively. Furthermore, Cu2+/Cu+ ions promote reactive oxygen species and electrostatically bind with the negatively charged teichoic acid in the bacterial cell wall. The anti-inflammatory and anti-diabetics analysis was conducted using standard BSA denaturation and α-amylase inhibition technique with cell inhibition values of 85.66 and 81.18% for TDCO3 NPs. Additionally, the TDCO3 NPs delivered prominent anticancer activity with the lowest IC50 value 18.2 μg/mL in the MTT assay technique against HeLa cancer cells.

Models for barrier understanding in health and disease in lab-on-a-chips

The maintenance of body homeostasis relies heavily on physiological barriers. Dysfunction of these barriers can lead to various pathological processes, including increased exposure to toxic materials and microorganisms. Various methods exist to investigate barrier function in vivo and in vitro. To investigate barrier function in a highly reproducible manner, ethically, and high throughput, researchers have turned to non-animal techniques and micro-scale technologies. In this comprehensive review, the authors summarize the current applications of organ-on-a-chip microfluidic devices in the study of physiological barriers. The review covers the blood-brain barrier, ocular barriers, dermal barrier, respiratory barriers, intestinal, hepatobiliary, and renal/bladder barriers under both healthy and pathological conditions. The article then briefly presents placental/vaginal, and tumour/multi-organ barriers in organ-on-a-chip devices. Finally, the review discusses Computational Fluid Dynamics in microfluidic systems that integrate biological barriers. This article provides a concise yet informative overview of the current state-of-the-art in barrier studies using microfluidic devices.

Advance in placenta drug delivery: concern for placenta-originated disease therapy

In the therapy of placenta-originated diseases during pregnancy, the main challenges are fetal exposure to drugs, which can pass through the placenta and cause safety concerns for fetal development. The design of placenta-resident drug delivery system is an advantageous method to minimize fetal exposure as well as reduce adverse maternal off-target effects. By utilizing the placenta as a biological barrier, the placenta-resident nanodrugs could be trapped in the local placenta to concentrate on the treatment of this abnormal originated tissue. Therefore, the success of such systems largely depends on the placental retention capacity. This paper expounds on the transport mechanism of nanodrugs in the placenta, analyzes the factors that affect the placental retention of nanodrugs, and summarizes the advantages and concerns of current nanoplatforms in the treatment of placenta-originated diseases. In general, this review aims to provide a theoretical basis for the construction of placenta-resident drug delivery systems, which will potentially enable safe and efficient clinical treatment for placenta-originated diseases in the future.

Nanoparticles at the maternal-fetal interface

The increasing production of intentional and unintentional nanoparticles (NPs) has led to their accumulation in the environment as air and ground pollution. The heterogeneity of these particles primarily relies on the NP physicochemical properties (i.e., chemical composition, size, shape, surface chemistry, etc.). Pregnancy represents a vulnerable life stage for both the woman and the developing fetus. The ubiquitous nature of these NPs creates a concern for developmental fetal exposures. At the maternal-fetal interface lies the placenta, a temporary endocrine organ that facilitates nutrient and waste exchange as well as communication between maternal and fetal tissues. Recent evidence in human and animal models identifies that gestational exposure to NPs results in placental translocation leading to local effects and endocrine disruption. Currently, the mechanisms underlying placental translocation and cellular uptake of NPs in the placenta are poorly understood. The purpose of this review is to assess the current understanding of the physiochemical factors influencing NP translocation, cellular uptake, and endocrine disruption at the maternal-fetal interface within the available literature.

Microfluidics for Development of Lipid Nanoparticles: Paving the Way for Nucleic Acids to the Clinic

Nucleic acid therapeutics hold an unprecedented promise toward treating many challenging diseases; however, their use is hampered by delivery issues. Microfluidics, dealing with fluids in the microscale dimensions, have provided a robust means to screening raw materials for development of nano delivery vectors, in addition to controlling their size and minimizing their polydispersity. In this mini-review, we are briefly highlighting the different types of nucleic acid therapies with emphasis on the delivery requirement for each type. We provide a thorough review of available methods for the development of nanoparticles, especially lipid nanoparticles (LNPs) that resulted in FDA approval of the first ever nucleic acid nanomedicine. We then focus on recent research attempts for how microfluidic synthesis of lipid nanoparticles and discuss the various parameters required for successful formulation of LPNs including chip design, flow regimes, and lipid composition. We then identify key areas of research in microfluidics and related fields that require attention for future success in clinical translation of nucleic acid nanomedicines.

Autophagy and Biomaterials: A Brief Overview of the Impact of Autophagy in Biomaterial Applications

Macroautophagy (hereafter autophagy), a tightly regulated physiological process that obliterates dysfunctional and damaged organelles and proteins, has a crucial role when biomaterials are applied for various purposes, including diagnosis, treatment, tissue engineering, and targeted drug delivery. The unparalleled physiochemical properties of nanomaterials make them a key component of medical strategies in different areas, such as osteogenesis, angiogenesis, neurodegenerative disease treatment, and cancer therapy. The application of implants and their modulatory effects on autophagy have been known in recent years. However, more studies are necessary to clarify the interactions and all the involved mechanisms. The advantages and disadvantages of nanomaterial-mediated autophagy need serious attention in both the biological and bioengineering fields. In this mini-review, the role of autophagy after biomaterial exploitation and the possible related mechanisms are explored.

Creating mini-pregnancy models in vitro with clinical perspectives

During the last decade, organs-on-chips or organoids microphysiological analysis platforms (MAP) have garnered attention in the practical applications of disease models, drug discovery, and developmental biology. Research on pregnant women has firm limitations due to ethical issues; thus, remodelling human pregnancy in vitro is highly beneficial for treatment modality development via disease remodelling or drug monitoring. This review highlights current efforts in bioengineering devices to reproduce human pregnancy and emphasises the significant convergence of biology, engineering, and maternal-foetal medicine. First, we review recent achievements in culturing cells from tissues involved in pregnancy; specifically, trophoblasts from the placenta. Second, we highlight developments in the reconstitution of pregnancy-related female reproductive organs across several structural and functional interpretations. Last, we examine research on the fundamental comprehension of pregnancy-associated diseases to find bioengineering solutions. Recreating human pregnancy through an engineered model is naturally complex; nevertheless, challenges are inevitable to progress precision medicine.

Shifting early embryology paradigms: Applications of stem cell-based embryo models in bioengineering

Technologies to reproduce specific aspects of early mammalian embryogenesis in vitro using stem cells have skyrocketed over the last several years. With these advances, we have gained new perspectives on how embryonic and extraembryonic cells self-organize to form the embryo. These reductionist approaches hold promise for the future implementation of precise environmental and genetic controls to understand variables affecting embryo development. Our review discusses recent progress in cellular models of early mammalian embryo development and bioengineering advancements that can be leveraged to study the embryo-maternal interface. We summarize current gaps in the field, emphasizing the importance of understanding how intercellular interactions at this interface contribute to reproductive and developmental health.

Effects of polycyclic aromatic hydrocarbons (PAHs) on pregnancy, placenta, and placental trophoblasts

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants that are carcinogenic, mutagenic, endocrine-toxic, and immunotoxic. PAHs can be found in maternal and fetal blood and in the placenta during pregnancy. They may thus affect placental and fetal development. Therefore, the exposure levels and toxic effects of PAHs in the placenta deserve further study and discussion. This review aims to summarize current knowledge on the effects of PAHs and their metabolites on pregnancy and birth outcomes and on placental trophoblast cells. A growing number of epidemiological studies detected PAH-DNA adducts as well as the 16 high-priority PAHs in the human placenta and showed that placental PAH exposure is associated with adverse fetal outcomes. Trophoblasts are important cells in the placenta and are involved in placental development and function. In vitro studies have shown that exposure to either PAH mixtures, benzo(a)pyrene (BaP) or BaP metabolite benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) affected trophoblast cell viability, differentiation, migration, and invasion through various signaling pathways. Furthermore, similar effects of BPDE on trophoblast cells could also be observed in BaP-treated mouse models and were related to miscarriage. Although the current data show that PAHs may affect placental trophoblast cells and pregnancy outcomes, further studies (population studies, in vitro studies, and animal studies) are necessary to show the specific effects of different PAHs on placental trophoblasts and pregnancy outcomes.

Gestational Viral Infections: Role of Host Immune System

Viral infections in pregnancy are major causes of maternal and fetal morbidity and mortality. Infections can develop in the neonate transplacentally, perinatally, or postnatally (from breast milk or other sources) and lead to different clinical manifestations, depending on the viral agent and the gestational age at exposure. Viewing the peculiar tolerogenic status which characterizes pregnancy, viruses could exploit this peculiar immunological status to spread or affect the maternal immune system, adopting several evasion strategies. In fact, both DNA and RNA virus might have a deep impact on both innate and acquired immune systems. For this reason, investigating the interaction with these pathogens and the host's immune system during pregnancy is crucial not only for the development of most effective therapies and diagnosis but mostly for prevention. In this review, we will analyze some of the most important DNA and RNA viruses related to gestational infections.

Experimental human placental models for studying uptake, transport and toxicity of micro- and nanoplastics

Micro- and nanoplastics (MNPs) are ubiquitous in the environment and have recently been found in human lungs, blood and placenta. However, data on the possible effects of MNPs on human health is extremely scarce. The potential toxicity of MNPs during pregnancy, a period of increased susceptibility to environmental insults, is of particular concern. The placenta provides a unique interface between maternal and fetal circulation which is essential for in utero survival and healthy pregnancy. Placental toxicokinetics and toxicity of MNPs are still largely unexplored and the limited studies performed up to now focus mainly on polystyrene particles. Practical and ethical considerations limit research options in humans, and extrapolation from animal studies is challenging due to marked differences between species. Nevertheless, diverse in vitro and ex vivo human placental models exist e.g., plasma membrane vesicles, mono-culture and co-culture of placental cells, placenta-on-a-chip, villous tissue explants, and placental perfusion that can be used to advance this research area. The objective of this concise review is to recapitulate different human placental models, summarize the current understanding of placental uptake, transport and toxicity of MNPs and define knowledge gaps. Moreover, we provide perspectives for future research urgently needed to assess the potential hazards and risks of MNP exposure to maternal and fetal health.

Translational Nanomedicines Across Human Reproductive Organs Modeling on Microfluidic Chips: State-of-the-Art and Future Prospects

Forecasting the consequence of nanoparticles (NPs) and therapeutically significant molecules before materializing for human clinical trials is a mainstay for drug delivery and screening processes. One of the noteworthy obstacles that has prevented the clinical translation of NP-based drug delivery systems and novel drugs is the lack of effective preclinical platforms. As a revolutionary technology, the organ-on-a-chip (OOC), a coalition of microfluidics and tissue engineering, has surfaced as an alternative to orthodox screening platforms. OOC technology recapitulates the structural and physiological features of human organs along with intercommunications between tissues on a chip. The current review discusses the concept of microfluidics and confers cutting-edge fabrication processes for chip designing. We also outlined the advantages of microfluidics in analyzing NPs in terms of characterization, transport, and degradation in biological systems. The review further elaborates the scope and research on translational nanomedicines in human reproductive organs (testis, placenta, uterus, and menstrual cycle) by taking the advantages offered by microfluidics and shedding light on their potential future implications. Finally, we accentuate the existing challenges for clinical translation and scale-up dynamics for microfluidics chips and emphasize its future perspectives.

Critical design parameters to develop biomimetic organ-on-a-chip models for the evaluation of the safety and efficacy of nanoparticles

INTRODUCTION

Organ-on-a-chip (OOC) models are based on microfluidics and can recapitulate the healthy and diseased microstructure of organs¹ and tissues and the dynamic microenvironment inside the human body. However, the use of OOC models to evaluate the safety and efficacy of nanoparticles (NPs) is still in the early stages.

AREAS COVERED

The different design parameters of the microfluidic chip and the mechanical forces generated by fluid flow play a pivotal role in simulating the human environment. This review discusses the role of different key parameters on the performance of OOC models. These include the flow pattern, flow rate, shear stress (magnitude, rate, and distribution), viscosity of the media, and the microchannel dimensions and shape. We also discuss how the shear stress and other mechanical forces affect the transport of NPs across biological barriers, cell uptake, and their biocompatibility.

EXPERT OPINION

We describe several good practices and design parameters to consider for future OOC research. We submit that following these recommendations will help realize the full potential of the OOC models in the preclinical evaluation of novel therapies, including NPs.

Design and Preparation of Sensing Surfaces for Capacitive Biodetection

Despite their high sensitivity and their suitability for miniaturization, biosensors are still limited for clinical applications due to the lack of reproducibility and specificity of their detection performance. The design and preparation of sensing surfaces are suspected to be a cause of these limitations. Here, we first present an updated overview of the current state of use of capacitive biosensors in a medical context. Then, we summarize the encountered strategies for the fabrication of capacitive biosensing surfaces. Finally, we describe the characteristics which govern the performance of the sensing surfaces, along with recent developments that were suggested to overcome their main current limitations.

Human Maternal-Fetal Interface Cellular Models to Assess Antiviral Drug Toxicity during Pregnancy

Pregnancy is a period of elevated risk for viral disease severity, resulting in serious health consequences for both the mother and the fetus; yet antiviral drugs lack comprehensive safety and efficacy data for use among pregnant women. In fact, pregnant women are systematically excluded from therapeutic clinical trials to prevent potential fetal harm. Current FDA-recommended reproductive toxicity assessments are studied using small animals which often do not accurately predict the human toxicological profiles of drug candidates. Here, we review the potential of human maternal-fetal interface cellular models in reproductive toxicity assessment of antiviral drugs. We specifically focus on the 2- and 3-dimensional maternal placental models of different gestational stages and those of fetal embryogenesis and organ development. Screening of drug candidates in physiologically relevant human maternal-fetal cellular models will be beneficial to prioritize selection of safe antiviral therapeutics for clinical trials in pregnant women.

3D microfluidics-assisted modeling of glucose transport in placental malaria

The human placenta is a critical organ, mediating the exchange of nutrients, oxygen, and waste products between fetus and mother. Placental malaria (PM) resulted from Plasmodium falciparum infections causes up to 200 thousand newborn deaths annually, mainly due to low birth weight, as well as 10 thousand mother deaths. In this work, a placenta-on-a-chip model is developed to mimic the nutrient exchange between the fetus and mother under the influence of PM. In this model, trophoblasts cells (facing infected or uninfected blood simulating maternal blood and termed “trophoblast side”) and human umbilical vein endothelial cells (facing uninfected blood simulating fetal blood and termed “endothelial” side) are cultured on the opposite sides of an extracellular matrix gel in a compartmental microfluidic system, forming a physiological barrier between the co-flow tubular structure to mimic a simplified maternal–fetal interface in placental villi. The influences of infected erythrocytes (IEs) sequestration through cytoadhesion to chondroitin sulfate A (CSA) expressed on the surface of trophoblast cells, a critical feature of PM, on glucose transfer efficiency across the placental barrier was studied. To create glucose gradients across the barrier, uninfected erythrocyte or IE suspension with a higher glucose concentration was introduced into the “trophoblast side” and a culture medium with lower glucose concentration was introduced into the “endothelial side”. The glucose levels in the endothelial channel in response to CSA-adherent erythrocytes infected with CS2 line of parasites in trophoblast channel under flow conditions was monitored. Uninfected erythrocytes served as a negative control. The results demonstrated that CSA-binding IEs added resistance to the simulated placental barrier for glucose perfusion and decreased the glucose transfer across this barrier. The results of this study can be used for better understanding of PM pathology and development of models useful in studying potential treatment of PM.

Placental Nanoparticle Uptake-On-a-Chip: The Impact of Trophoblast Syncytialization and Shear Stress

The placenta is a dynamic and complex organ that plays an essential role in the health and development of the fetus. Placental disorders can affect the health of both the mother and the fetus. There is currently an unmet clinical need to develop nanoparticle-based therapies to target and treat placental disorders. However, little is known about the interaction of nanoparticles (NPs) with the human placenta under biomimetic conditions. Specifically, the impact of shear stress exerted on the trophoblasts (placental epithelial cells) by the maternal blood flow, the gradual fusion of the trophoblasts along the gestation period (syncytialization), and the impact of microvilli formation on the cell uptake of NPs is not known. To this end, we designed dynamic placenta-on-a-chip models using BeWo cells to recapitulate the micro-physiological environment, and we induced different degrees of syncytialization via chemical induction with forskolin. We characterized the degree of syncytialization quantitatively by measuring beta human chorionic gonadotropin (β-hCG) secretion, as well as qualitatively by immunostaining the tight junction protein, ZO-1, and counter nuclear staining. We also characterized microvilli formation under static and dynamic conditions via F-actin staining. We used these models to measure the cell uptake of chondroitin sulfate a binding protein (CSA) conjugated and control liposomes using confocal microscopy, followed by image analysis. Interestingly, exposure of the cells to a dynamic flow of media intrinsically induced syncytialization and microvilli formation compared to static controls. Under dynamic conditions, BeWo cells produced more β-hCG in conditions that increased the cell exposure time to forskolin (p < 0.005). Our cell uptake results clearly show a combined effect of the exerted shear stress and forskolin treatment on the cell uptake of liposomes as uptake increased in forskolin exposed conditions (p < 0.05). Overall, the difference in the extent of cell uptake of liposomes among the different conditions clearly displays a need for the development of dynamic models of the placenta that consider the changes in the placental cell phenotype along the gestation period, including syncytialization, microvilli formation, and the expression of different transport and uptake receptors. Knowledge generated from this work will inform future research aiming at developing drug delivery systems targeting the placenta.

Nanotechnologies in Obstetrics and Cancer during Pregnancy: A Narrative Review

Nanotechnology, the art of engineering structures on a molecular level, offers the opportunity to implement new strategies for the diagnosis and management of pregnancy-related disorders. This review aims to summarize the current state of nanotechnology in obstetrics and cancer in pregnancy, focusing on existing and potential applications, and provides insights on safety and future directions. A systematic and comprehensive literature assessment was performed, querying the following databases: PubMed/Medline, Scopus, and Endbase. The databases were searched from their inception to 22 March 2022. Five independent reviewers screened the items and extracted those which were more pertinent within the scope of this review. Although nanotechnology has been on the bench for many years, most of the studies in obstetrics are preclinical. Ongoing research spans from the development of diagnostic tools, including optimized strategies to selectively confine contrast agents in the maternal bloodstream and approaches to improve diagnostics tests to be used in obstetrics, to the synthesis of innovative delivery nanosystems for therapeutic interventions. Using nanotechnology to achieve spatial and temporal control over the delivery of therapeutic agents (e.g., commonly used drugs, more recently defined formulations, or gene therapy-based approaches) offers significant advantages, including the possibility to target specific cells/tissues of interest (e.g., the maternal bloodstream, uterus wall, or fetal compartment). This characteristic of nanotechnology-driven therapy reduces side effects and the amount of therapeutic agent used. However, nanotoxicology appears to be a significant obstacle to adopting these technologies in clinical therapeutic praxis. Further research is needed in order to improve these techniques, as they have tremendous potential to improve the accuracy of the tests applied in clinical praxis. This review showed the increasing interest in nanotechnology applications in obstetrics disorders and pregnancy-related pathologies to improve the diagnostic algorithms, monitor pregnancy-related diseases, and implement new treatment strategies.

Current understanding in deciphering trophoblast cell differentiation during human placentation

The placenta is a unique organ that forms during gestation and supports fetus survival and communication with the mother. However, of such an arguably essential organ for a successful pregnancy, our knowledge is limited. New progress has been made for human placenta study in recent years. We herein summarize the current understanding of human placental trophoblast differentiation and the molecules that govern trophoblast cell lineage specification. More importantly, the powerful tools for placental studies are also explained, such as human trophoblast stem cells (hTSCs), 3-dimensional (3D) trophoblast organoids, engineering-based placental devices, and single-cell RNA sequencing (sc-RNAseq). These advances have brought us new insights into placental development and provided multiple investigation strategies for deciphering molecular mechanisms.

Targeted drug delivery for maternal and perinatal health: Challenges and opportunities

Pre-existing conditions at reproductive age, and complications arising during pregnancy can be detrimental to maternal and fetal health. Current therapies to combat obstetric disorders are limited due to the inherent complexity of pregnancy, and can have harmful effects on developing fetus. Emerging research shows intricate signaling between the cells from mother and fetus at maternal-fetal interface, providing unique opportunities for interventions specifically targeted to the mother, fetus, or placenta. Advancements in nanotechnology, stem-cell biology and gene therapy have resulted in target-specific treatments with promising results in pre-clinical maternal and fetal disorder models. Comprehensive understanding of the effect of physicochemical properties of delivery systems on their uptake, retention and accumulation across placenta will help in the better diagnosis and treatment of perinatal disorders. This review describes the factors leading to obstetric complications along with their effect on pregnancy outcomes, and discusses key targeted therapeutic strategies for addressing conditions related to maternal and fetal health.