Bio

Professional Education


  • Doctor of Philosophy, Ohio State University (2017)
  • Bachelor of Technology, Vellore Institute Technology (2008)
  • Master of Science, New Jersey Institute Of Technology (2011)

Research & Scholarship

Lab Affiliations


Publications

All Publications


  • Targeted production of reactive oxygen species in mitochondria to overcome cancer drug resistance NATURE COMMUNICATIONS Wang, H., Gao, Z., Liu, X., Agarwal, P., Zhao, S., Conroy, D. W., Ji, G., Yu, J., Jaroniec, C. P., Liu, Z., Lu, X., Li, X., He, X. 2018; 9: 562

    Abstract

    Multidrug resistance is a major challenge to cancer chemotherapy. The multidrug resistance phenotype is associated with the overexpression of the adenosine triphosphateá(ATP)-driven transmembrane efflux pumps in cancer cells. Here, we report a lipid membrane-coated silica-carboná(LSC) hybrid nanoparticle that targets mitochondria through pyruvate, to specifically produce reactive oxygen speciesá(ROS) in mitochondria under near-infraredá(NIR) laser irradiation. The ROS can oxidize the NADH into NAD+ to reduce the amount of ATP available for the efflux pumps. The treatment with LSC nanoparticles and NIR laser irradiation also reduces the expression and increases the intracellular distribution of the efflux pumps. Consequently, multidrug-resistant cancer cells lose their multidrug resistance capability for at least 5 days, creating a therapeutic window for chemotherapy. Our in vivo data show that the drug-laden LSC nanoparticles in combination with NIR laser treatment can effectively inhibit the growth of multidrug-resistant tumors with no evident systemic toxicity.

    View details for DOI 10.1038/s41467-018-02915-8

    View details for Web of Science ID 000424451300007

    View details for PubMedID 29422620

    View details for PubMedCentralID PMC5805731

  • A Nano-In-Micro System for Enhanced Stem Cell Therapy of Ischemic Diseases ACS CENTRAL SCIENCE Wang, H., Agarwal, P., Xiao, Y., Peng, H., Zhao, S., Liu, X., Zhou, S., Li, J., Liu, Z., He, X. 2017; 3 (8): 875?85

    Abstract

    Stem cell therapy holds great potential for treating ischemic diseases. However, contemporary methods for local stem cell delivery suffer from poor cell survival/retention after injection. We developed a unique multiscale delivery system by encapsulating therapeutic agent-laden nanoparticles in alginate hydrogel microcapsules and further coentrapping the nano-in-micro capsules with stem cells in collagen hydrogel. The multiscale system exhibits significantly higher mechanical strength and stability than pure collagen hydrogel. Moreover, unlike nanoparticles, the nano-in-micro capsules do not move with surrounding body fluid and are not taken up by the cells. This allows a sustained and localized release of extracellular epidermal growth factor (EGF), a substance that could significantly enhance the proliferation of mesenchymal stem cells while maintaining their multilineage differentiation potential via binding with its receptors on the stem cell surface. As a result, the multiscale system significantly improves the stem cell survival at 8 days after implantation to ?70% from ?4-7% for the conventional system with nanoparticle-encapsulated EGF or free EGF in collagen hydrogel. After injecting into the ischemic limbs of mice, stem cells in the multiscale system facilitate tissue regeneration to effectively restore ?100% blood perfusion in 4 weeks without evident side effects.

    View details for DOI 10.1021/acscentsci.7b00213

    View details for Web of Science ID 000408141900012

    View details for PubMedID 28852702

    View details for PubMedCentralID PMC5571461

  • Microfluidics Enabled Bottom-Up Engineering of 3D Vascularized Tumor for Drug Discovery ACS NANO Agarwal, P., Wang, H., Sun, M., Xu, J., Zhao, S., Liu, Z., Gooch, K. J., Zhao, Y., Lu, X., He, X. 2017; 11 (7): 6691?6702

    Abstract

    Development of high-fidelity three-dimensional (3D) models to recapitulate the tumor microenvironment is essential for studying tumor biology and discovering anticancer drugs. Here we report a method to engineer the 3D microenvironment of human tumors, by encapsulating cancer cells in the core of microcapsules with a hydrogel shell for miniaturized 3D culture to obtain avascular microtumors first. The microtumors are then used as the building blocks for assembling with endothelial cells and other stromal cells to create macroscale 3D vascularized tumor. Cells in the engineered 3D microenvironment can yield significantly larger tumors in vivo than 2D-cultured cancer cells. Furthermore, the 3D vascularized tumors are 4.7 and 139.5 times more resistant to doxorubicin hydrochloride (a commonly used chemotherapy drug) than avascular microtumors and 2D-cultured cancer cells, respectively. Moreover, this high drug resistance of the 3D vascularized tumors can be overcome by using nanoparticle-mediated drug delivery. The high-fidelity 3D tumor model may be valuable for studying the effect of microenvironment on tumor progression, invasion, and metastasis and for developing effective therapeutic strategy to fight against cancer.

    View details for DOI 10.1021/acsnano.7b00824

    View details for Web of Science ID 000406649700017

    View details for PubMedID 28614653

    View details for PubMedCentralID PMC5663446

  • Bioengineering of injectable encapsulated aggregates of pluripotent stem cells for therapy of myocardial infarction NATURE COMMUNICATIONS Zhao, S., Xu, Z., Wang, H., Reese, B. E., Gushchina, L. V., Jiang, M., Agarwal, P., Xu, J., Zhang, M., Shen, R., Liu, Z., Weisleder, N., He, X. 2016; 7: 13306

    Abstract

    It is difficult to achieve minimally invasive injectable cell delivery while maintaining high cell retention and animal survival for in vivo stem cell therapy of myocardial infarction. Here we show that pluripotent stem cell aggregates pre-differentiated into the early cardiac lineage and encapsulated in a biocompatible and biodegradable micromatrix, are suitable for injectable delivery. This method significantly improves the survival of the injected cells by more than six-fold compared with the conventional practice of injecting single cells, and effectively prevents teratoma formation. Moreover, this method significantly enhances cardiac function and survival of animals after myocardial infarction, as a result of a localized immunosuppression effect of the micromatrix and the in situ cardiac regeneration by the injected cells.

    View details for DOI 10.1038/ncomms13306

    View details for Web of Science ID 000386310100001

    View details for PubMedID 27786170

    View details for PubMedCentralID PMC5095349

  • Continuous On-Chip Cell Separation Based on Conductivity-Induced Dielectrophoresis with 3D Self-Assembled Ionic Liquid Electrodes ANALYTICAL CHEMISTRY Sun, M., Agarwal, P., Zhao, S., Zhao, Y., Lu, X., He, X. 2016; 88 (16): 8264?71

    Abstract

    Dielectrophoresis (DEP) has been widely explored to separate cells for various applications. However, existing DEP devices are limited by the high cost associated with the use of noble metal electrodes, the need of high-voltage electric field, and/or discontinuous separation (particularly for devices without metal electrodes). We developed a DEP device with liquid electrodes, which can be used to continuously separate different types of cells or particles based on positive DEP. The device is made of polydimethylsiloxane (PDMS), and ionic liquid is used to form the liquid electrodes, which has the advantages of low cost and easy fabrication. Moreover, the conductivity gradient is utilized to achieve the DEP-based on-chip cell separation. The device was used to separate polystyrene microbeads and PC-3 human prostate cancer cells with 94.7 and 1.2% of the cells and microbeads being deflected, respectively. This device is also capable of separating live and dead PC-3 cancer cells with 89.8 and 13.2% of the live and dead cells being deflected, respectively. Moreover, MDA-MB-231 human breast cancer cells could be separated from human adipose-derived stem cells (ADSCs) using this device with high purity (81.8 and 82.5% for the ADSCs and MDA-MB-231 cells, respectively). Our data suggest the great potential of cell separation based on conductivity-induced DEP using affordable microfluidic devices with easy operation.

    View details for DOI 10.1021/acs.analchem.6b02104

    View details for Web of Science ID 000381654800053

    View details for PubMedID 27409352

    View details for PubMedCentralID PMC5497574

  • Combined cancer therapy with hyaluronan-decorated fullerene-silica multifunctional nanoparticles to target cancer stem-like cells BIOMATERIALS Wang, H., Agarwal, P., Zhao, S., Yu, J., Lu, X., He, X. 2016; 97: 62?73

    Abstract

    Cancer stem-like cells (CSCs) are resistant to chemotherapy and highly tumorigenic, which contributes to tumor occurrence and post-treatment relapse. We developed a novel C60 fullerene-silica nanoparticle system surface-decorated with hyaluronan (HA) to target the variant CD44 overexpressed on breast CSCs. Furthermore, doxorubicin hydrochloride (DOX) and indocyanine green (ICG) can be encapsulated in the nanoparticles with ultrahigh encapsulation efficiency (>90%) and loading content (e.g., 48.5% at a drug-to-nanoparticle feeding ratio of 1:1, compared to the commonly used drug-to-nanoparticle feeding ratio of 1:20 with a drug loading content of less than 5%). As a result, the DOX and ICG-laden nanoparticles can be used as a single nanoplatform to achieve combined chemo, photodynamic, and photothermal therapy under near infrared laser irradiation for effective destruction of the breast CSCs both inávitro and inávivo, with no evident systemic toxicity. Moreover, we found the nanoparticles with a higher drug loading content (e.g., 48.5 versus 4.6%) also have significantly higher antitumor efficacy, given the same total drug dose. These results demonstrate the great potential of the multifunctional hybrid nanoparticle system for augmenting cancer therapy by eliminating the CSCs.

    View details for DOI 10.1016/j.biomaterials.2016.04.030

    View details for Web of Science ID 000377735800006

    View details for PubMedID 27162075

    View details for PubMedCentralID PMC4957695

  • The Effect of RGD Peptide on 2D and Miniaturized 3D Culture of HEPM Cells, MSCs, and ADSCs with Alginate Hydrogel CELLULAR AND MOLECULAR BIOENGINEERING Dumbleton, J., Agarwal, P., Huang, H., Hogrebe, N., Han, R., Gooch, K. J., He, X. 2016; 9 (2): 277?88

    Abstract

    Advancements in tissue engineering require the development of new technologies to study cell behavior in vitro. This study focuses on stem cell behavior within various miniaturized three-dimensional (3D) culture conditions of alginate biomaterials modified with the Arg-Gly-Asp (RGD) peptide known for its role in cell adhesion/attachment. Human embryonic palatal mesenchyme (HEPM) cells, bone marrow derived mesenchymal stem cells (MSCs), and human adipose derived stem cells (ADSCs) were cultured on a flat hydrogel of different concentrations of alginate-RGD, and in the miniaturized 3D core of microcapsules with either a 2% alginate or 2% alginate-RGD shell. The core was made of 0%, 0.5%, or 2% alginate-RGD. Cell spreading was observed in all systems containing the RGD peptide, and the cell morphology was quantified by measuring the cell surface area and circularity. In all types of stem cells, there was a significant increase in the cell surface area (p < 0.05) and a significant decrease in cell circularity (p < 0.01) in alginate-RGD conditions, indicating that cells spread much more readily in environments containing the peptide. This control over the cell spreading within a 3D microenvironment can help to create the ideal biomimetic condition in which to conduct further studies on cell behavior.

    View details for DOI 10.1007/s12195-016-0428-9

    View details for Web of Science ID 000377409700010

    View details for PubMedID 27990180

    View details for PubMedCentralID PMC5157694

  • A Near-Infrared Laser- Activated "Nanobomb" for Breaking the Barriers to MicroRNA Delivery ADVANCED MATERIALS Wang, H., Agarwal, P., Zhao, S., Yu, J., Lu, X., He, X. 2016; 28 (2): 347?55

    Abstract

    A near-infrared laser-activated "nanobomb" is synthesized using lipid and multiple polymers to break the extra-cellular and intracellular barriers to cytosolic delivery of microRNAs. The nanobomb can be used to effectively destroy tumors and cancer stem-like cells in vitro and in vivo with minimal side effects.

    View details for DOI 10.1002/adma.201504263

    View details for Web of Science ID 000367842400018

    View details for PubMedID 26567892

  • A biomimetic hybrid nanoplatform for encapsulation and precisely controlled delivery of theranostic agents (vol 6, 10081, 2015) NATURE COMMUNICATIONS Wang, H., Agarwal, P., Zhao, S., Yu, J., Lu, X., He, X. 2016; 7: 10350

    View details for DOI 10.1038/ncomms10350

    View details for Web of Science ID 000369019000004

    View details for PubMedID 26739909

    View details for PubMedCentralID PMC4729838

  • Hyaluronic acid-decorated dual responsive nanoparticles of Pluronic F127, PLGA, and chitosan for targeted co-delivery of doxorubicin and irinotecan to eliminate cancer stem-like cells BIOMATERIALS Wang, H., Agarvval, P., Zhao, S., Xu, R. X., Yu, J., Lu, X., He, X. 2015; 72: 74?89

    Abstract

    Dual responsive nanoparticles are developed for co-delivery of multiple anticancer drugs to target the drug resistance mechanisms of cancer stem-like cells (CSCs). The nanoparticles consist of four polymers approved by the Food and Drug Administration (FDA) for medical use: Poly(d,l-lactide-co-glycolide) (PLGA), Pluronic F127 (PF127), chitosan, and hyaluronic acid (HA). By combining PLGA and PF127 together, more stable and uniform-sized nanoparticles can be obtained than using PLGA or PF127 alone. The HA is used for not only actively targeting CSCs to reduce their drug resistance due to dormancy (i.e., slow metabolism), but also replacing the commonly used poly(vinyl alcohol) as a stabilizing agent to synthesize the nanoparticles using the double-emulsion approach and to allow for acidic pH-triggered drug release and thermal responsiveness. Besides minimizing drug efflux from CSCs, the nanoparticles encapsulated with doxorubicin hydrochloride (DOX, hydrophilic) and irinotecan (CPT, hydrophobic) to inhibit the activity of topoisomerases II and I, respectively, can fight against the CSC drug resistance associated with their enhanced DNA repair and anti-apoptosis. Ultimately, the two drugs-laden nanoparticles can be used to efficiently destroy the CSCs both inávitro and inávivo with up to ?500 times of enhancement compared to the simple mixture of the two drugs.

    View details for DOI 10.1016/j.biomaterials.2015.08.048

    View details for Web of Science ID 000362926600008

    View details for PubMedID 26344365

    View details for PubMedCentralID PMC5003084

  • Alginate Hydrogel Microencapsulation Inhibits Devitrification and Enables Large-Volume Low-CPA Cell Vitrification ADVANCED FUNCTIONAL MATERIALS Huang, H., Choi, J., Rao, W., Zhao, S., Agarwal, P., Zhao, G., He, X. 2015; 25 (44): 6839?50

    Abstract

    Cryopreservation of stem cells is important to meet their ever-increasing demand by the burgeoning cell-based medicine. The conventional slow freezing for stem cell cryopreservation suffers from inevitable cell injury associated with ice formation and the vitrification (i.e., no visible ice formation) approach is emerging as a new strategy for cell cryopreservation. A major challenge to cell vitrification is intracellular ice formation (IIF, a lethal event to cells) induced by devitrification (i.e., formation of visible ice in previously vitrified solution) during warming the vitrified cells at cryogenic temperature back to super-zero temperatures. Consequently, high and toxic concentrations of penetrating cryoprotectants (i.e., high CPAs, up to ~8 M) and/or limited sample volumes (up to ~2.5 ?l) have been used to minimize IIF during vitrification. We reveal that alginate hydrogel microencapsulation can effectively inhibit devitrification during warming. Our data show that if ice formation were minimized during cooling, IIF is negligible in alginate hydrogel-microencapsulated cells during the entire cooling and warming procedure of vitrification. This enables vitrification of pluripotent and multipotent stem cells with up to ~4 times lower concentration of penetrating CPAs (up to 2 M, low CPA) in up to ~100 times larger sample volume (up to ~250 ?l, large volume).

    View details for DOI 10.1002/adfm.201503047

    View details for Web of Science ID 000366501100002

    View details for PubMedID 26640426

    View details for PubMedCentralID PMC4667367

  • A Biomimetic Core-Shell Platform for Miniaturized 3D Cell and Tissue Engineering PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION Agarwal, P., Choi, J., Huang, H., Zhao, S., Dumbleton, J., Li, J., He, X. 2015; 32 (8): 809?16

    Abstract

    This article describes a biomimetic core-shell platform with a collagen-based core and an alginate hydrogel shell for cell and tissue culture. With this system, chemical and physical properties of extracellular matrix (ECM) in the core microenvironment can be controlled to regulate proliferation and development of cells/tissues under miniaturized three-dimensional (3D) culture.

    View details for DOI 10.1002/ppsc.201500025

    View details for Web of Science ID 000359916400002

    View details for PubMedID 26457002

    View details for PubMedCentralID PMC4594878

  • Chitosan-Decorated Doxorubicin-Encapsulated Nanoparticle Targets and Eliminates Tumor Reinitiating Cancer Stem-like Cells ACS NANO Rao, W., Wang, H., Han, J., Zhao, S., Dumbleton, J., Agarwal, P., Zhang, W., Zhao, G., Yu, J., Zynger, D. L., Lu, X., He, X. 2015; 9 (6): 5725?40

    Abstract

    Tumor reinitiating cancer stem-like cells are responsible for cancer recurrence associated with conventional chemotherapy. We developed a doxorubicin-encapsulated polymeric nanoparticle surface-decorated with chitosan that can specifically target the CD44 receptors of these cells. This nanoparticle system was engineered to release the doxorubicin in acidic environments, which occurs when the nanoparticles are localized in the acidic tumor microenvironment and when they are internalized and localized in the cellular endosomes/lysosomes. This nanoparticle design strategy increases the cytotoxicity of the doxorubicin by six times in comparison to the use of free doxorubicin for eliminating CD44(+) cancer stem-like cells residing in 3D mammary tumor spheroids (i.e., mammospheres). We further show these nanoparticles reduced the size of tumors in an orthotopic xenograft tumor model with no evident systemic toxicity. The development of nanoparticle system to target cancer stem-like cells with low systemic toxicity provides a new treatment arsenal for improving the survival of cancer patients.

    View details for DOI 10.1021/nn506928p

    View details for Web of Science ID 000356988500012

    View details for PubMedID 26004286

  • Multi-layered polymeric nanoparticles for pH-responsive and sequenced release of theranostic agents CHEMICAL COMMUNICATIONS Wang, H., Zhao, S., Agarwal, P., Dumbleton, J., Yu, J., Lu, X., He, X. 2015; 51 (36): 7733?36

    Abstract

    In this study, multi-layered pH-responsive polymeric nanoparticles (NPs) are prepared by multiple (up to 4) emulsifications to encapsulate multiple hydrophilic and hydrophobic theranostic agents for controlled and sequenced release. It is found that the sequence of release of multiple chemotherapeutic agents from the NPs significantly affects their efficacy against cancer cells.

    View details for DOI 10.1039/c5cc01833a

    View details for Web of Science ID 000353218700036

    View details for PubMedID 25850616

  • Coaxial electrospray of liquid core-hydrogel shell microcapsules for encapsulation and miniaturized 3D culture of pluripotent stem cells INTEGRATIVE BIOLOGY Zhao, S., Agarwal, P., Rao, W., Huang, H., Zhang, R., Liu, Z., Yu, J., Weisleder, N., Zhang, W., He, X. 2014; 6 (9): 874?84

    Abstract

    A novel coaxial electrospray technology is developed to generate microcapsules with a hydrogel shell of alginate and an aqueous liquid core of living cells using two aqueous fluids in one step. Approximately 50 murine embryonic stem (ES) cells encapsulated in the core with high viability (92.3 ▒ 2.9%) can proliferate to form a single ES cell aggregate of 128.9 ▒ 17.4 ?m in each microcapsule within 7 days. Quantitative analyses of gene and protein expression indicate that ES cells cultured in the miniaturized 3D liquid core of the core-shell microcapsules have significantly higher pluripotency on average than the cells cultured on the 2D substrate or in the conventional 3D alginate hydrogel microbeads without a core-shell architecture. The higher pluripotency is further suggested by their significantly higher capability of differentiation into beating cardiomyocytes and higher expression of cardiomyocyte specific gene markers on average after directed differentiation under the same conditions. Considering its wide availability, easiness to set up and operate, reusability, and high production rate, the novel coaxial electrospray technology together with the microcapsule system is of importance for mass production of ES cells with high pluripotency to facilitate translation of the emerging pluripotent stem cell-based regenerative medicine into the clinic.

    View details for DOI 10.1039/c4ib00100a

    View details for Web of Science ID 000340780600005

    View details for PubMedID 25036382

    View details for PubMedCentralID PMC4138297

  • The crucial role of mechanical heterogeneity in regulating follicle development and ovulation with engineered ovarian microtissue BIOMATERIALS Choi, J., Agarvval, P., Huang, H., Zhao, S., He, X. 2014; 35 (19): 5122?28

    Abstract

    Contemporary systems for in vitro culture of ovarian follicles do not recapitulate the mechanical heterogeneity in mammalian ovary. Here we report microfluidic generation of biomimetic ovarian microtissue for miniaturized three-dimensional (3D) culture of early secondary preantral follicles by using alginate (harder) and collagen (softer) to fabricate the ovarian cortical and medullary tissues, respectively. This biomimetic configuration greatly facilitates follicle development to antral stage. Moreover, it enables in vitro ovulation of cumulus-oocyte complex (COC) from the antral follicles in the absence of luteinizing hormone (LH) and epidermal growth factor (EGF) that are well accepted to be responsible for ovulation in contemporary literature. These data reveal the crucial role of mechanical heterogeneity in the mammalian ovary in regulating follicle development and ovulation. The biomimetic ovarian microtissue and the microfluidic technology developed in this study are valuable for improving in vitro culture of follicles to preserve fertility and for understanding the mechanism of follicle development and ovulation to facilitate the search of cures to infertility due to ovarian disorders.

    View details for DOI 10.1016/j.biomaterials.2014.03.028

    View details for Web of Science ID 000335705600009

    View details for PubMedID 24702961

    View details for PubMedCentralID PMC4016819

  • Thermally responsive nanoparticle-encapsulated curcumin and its combination with mild hyperthermia for enhanced cancer cell destruction ACTA BIOMATERIALIA Rao, W., Zhang, W., Poventud-Fuentes, I., Wang, Y., Lei, Y., Agarwal, P., Weekes, B., Li, C., Lu, X., Yu, J., He, X. 2014; 10 (2): 831?42

    Abstract

    In this study, thermally responsive polymeric nanoparticle-encapsulated curcumin (nCCM) was prepared and characterized. The nCCM is ? 22 and 300 nm in diameter at 37 and 22 ░C, respectively. The smaller size of the nCCM at 37 ░C was found to significantly facilitate its uptake in vitro by human prostate adenocarcinoma PC-3 cancer cells. However, the intracellular nCCM decreases rapidly (rather than plateaus) after reaching its peak at ? 1.5 h during a 3-day incubation of the PC-3 cells with nCCM. Moreover, a mild hyperthermia (with negligible cytotoxicity alone) at 43 ░C applied between 1 and 1.5 h during the 3-day incubation not only increases the peak uptake but also alters intracellular distribution of nCCM (facilitating its delivery into cell nuclei), which helps to retain a significantly much higher level of intracellular curcumin. These effects of mild hyperthermia could be due in part to the thermal responsiveness of the nCCM: they are more positively charged at 43 ░C and can be more easily attracted to the negatively charged nuclear membrane to enter nuclei as a result of electrostatic interaction. Ultimately, a combination of the thermally responsive nCCM and mild hyperthermia significantly enhances the anticancer capability of nCCM, resulting in a more than 7-fold decrease in its inhibitory concentration to reduce cell viability to 50% (IC50). Further mechanistic studies suggest injury pathways associated with heat shock proteins 27 and 70 should contribute to the enhanced cancer cell destruction by inducing cell apoptosis and necrosis. Overall, this study demonstrates the potential of combining mild hyperthermia and thermally responsive nanodrugs such as nCCM for augmented cancer therapy.

    View details for DOI 10.1016/j.actbio.2013.10.020

    View details for Web of Science ID 000330921700028

    View details for PubMedID 24516867

    View details for PubMedCentralID PMC4136765

  • In Vitro Culture of Early Secondary Preantral Follicles in Hanging Drop of Ovarian Cell-Conditioned Medium to Obtain MII Oocytes from Outbred Deer Mice TISSUE ENGINEERING PART A Choi, J., Agarwal, P., He, X. 2013; 19 (23-24): 2626?37

    Abstract

    The ovarian follicle (each contains a single oocyte) is the fundamental functional tissue unit of mammalian ovaries. In humans, it has been long held true that females are born with a maximum number of follicles (or oocytes) that are not only nonrenewable, but also undergoing degeneration with time with a sharply decreased oocyte quality after the age of ?35. Therefore, it is of importance to isolate and bank ovarian follicles for in vitro culture to obtain fertilizable oocytes later, to preserve the fertility of professional women who may want to delay childbearing, young and unmarried women who may lose gonadal function because of exposure to environmental/occupational hazards or aggressive medical treatments, such as radiation and chemotherapy, and even endangered species and breeds. Although they contributed significantly to the understanding of follicle science and biology, most studies reported to date on this topic were done using the man-made, unnatural inbred animal species. It was found in this study that the conventional two-dimensional microliter drop and three-dimensional hanging drop (HD) methods, reported to be effective for in vitro culture of preantral follicles from inbred mice, are not directly transferrable to outbred deer mice. Therefore, a modified HD method was developed in this study to achieve a much higher (>5 times compared to the best conventional methods) percentage of developing early secondary preantral follicles from the outbred mice to the antral stage, for which, the use of an ovarian cell-conditioned medium and multiple follicles per HD were identified to be crucial. It was further found that the method for in vitro maturation of oocytes in antral follicles obtained by in vitro culture of preantral follicles could be very different from that for oocytes in antral follicles obtained by hormone stimulation in vivo. Therefore, this study should provide important guidance for establishing effective protocols of in vitro follicle culture to preserve the fertility of wildlife and humans outbred by nature.

    View details for DOI 10.1089/ten.tea.2013.0055

    View details for Web of Science ID 000328333700010

    View details for PubMedID 23789595

    View details for PubMedCentralID PMC3856600

  • One-step microfluidic generation of pre-hatching embryo-like core-shell microcapsules for miniaturized 3D culture of pluripotent stem cells LAB ON A CHIP Agarwal, P., Zhao, S., Bielecki, P., Rao, W., Choi, J., Zhao, Y., Yu, J., Zhang, W., He, X. 2013; 13 (23): 4525?33

    Abstract

    A novel core-shell microcapsule system is developed in this study to mimic the miniaturized 3D architecture of pre-hatching embryos with an aqueous liquid-like core of embryonic cells and a hydrogel-shell of zona pellucida. This is done by microfabricating a non-planar microfluidic flow-focusing device that enables one-step generation of microcapsules with an alginate hydrogel shell and an aqueous liquid core of cells from two aqueous fluids. Mouse embryonic stem (ES) cells encapsulated in the liquid core are found to survive well (>92%). Moreover, ~20 ES cells in the core can proliferate to form a single ES cell aggregate in each microcapsule within 7 days while at least a few hundred cells are usually needed by the commonly used hanging-drop method to form an embryoid body (EB) in each hanging drop. Quantitative RT-PCR analyses show significantly higher expression of pluripotency marker genes in the 3D aggregated ES cells compared to the cells under 2D culture. The aggregated ES cells can be efficiently differentiated into beating cardiomyocytes using a small molecule (cardiogenol C) without complex combination of multiple growth factors. Taken together, the novel 3D microfluidic and pre-hatching embryo-like microcapsule systems are of importance to facilitate in vitro culture of pluripotent stem cells for their ever-increasing use in modern cell-based medicine.

    View details for DOI 10.1039/c3lc50678a

    View details for Web of Science ID 000326983300005

    View details for PubMedID 24113543

    View details for PubMedCentralID PMC3848340

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