High throughput direct 3D bioprinting in multiwell plates.

Advances in three dimensional (3D) bioprinting have enabled the fabrication of sophisticated 3D tissue scaffolds for biological and medical applications, where high speed, high throughput production in well plates is a critical need. Here, we present an integrated 3D bioprinting platform based on microscale continuous optical printing, capable of high throughputin siturapid fabrication of complex 3D biomedical samples in multiwell plate formats for subsequent culture and analysis. Our high throughput 3D bioprinter (HT-3DP) was used to showcase constructs of varying spatial geometries of biomimetic significance, tunable mechanical properties, as well as reproducibility. Live hepatocellular carcinoma 3D tissue scaffolds were fabricatedin situin multiwell plates, after which a functional drug response assay against the chemotherapy drug doxorubicin was performed. Dual cell-type populations involving both live hepatocellular carcinoma as well as human umbilical vein endothelial cells were also printed to demonstrate dual-tissue fabrication capability. This work demonstrates a significant advancement in that the production rate of 3D bioprinted tissue scaffolds with controllable spatial architectures and mechanical properties can now be done on a high throughput scale, enabling rapid generation ofin vitro3D tissue models within conventional multiwell cell culture plates for high throughput preclinical drug screening and disease modeling.

Direct 3D bioprinting of cardiac micro-tissues mimicking native myocardium.

The heart possesses a complex three-dimensional (3D) laminar myofiber organization; however, because engineering physiologically relevant 3D tissues remains a technical challenge, the effects of cardiomyocyte alignment on excitation-contraction coupling, shortening and force development have not been systematically studied. Cellular shape and orientations in 3D can be controlled by engineering scaffold microstructures and encapsulating cells near these geometric cues. Here, we show that a novel method of cell encapsulation in 3D methacrylated gelatin (GelMA) scaffolds patterned via Microscale Continuous Optical Printing (µCOP) can rapidly micropattern neonatal mouse ventricular cardiomyocytes (NMVCMs) in photocrosslinkable hydrogels. Encapsulated cardiomyocytes preferentially align with the engineered microarchitecture and can display morphology and myofibril alignment phenotypic of myocardium in vivo. Utilizing the µCOP system, an asymmetric, multi-material, cantilever-based scaffold was directly printed, so that the force produced by the microtissue was transmitted onto a single deformable pillar. Aligned 3D encapsulated NMVCM scaffolds produced nearly 2 times the force compared to aligned 2D seeded samples. To further highlight the flexibility of µCOP, NMVCMs were encapsulated in several patterns to compare the effects of varying degrees of alignment on tissue displacement and synchronicity. Well aligned myofiber cultured patterns generated 4-10 times the contractile force of less anisotropically patterned constructs. Finally, normalized fluo-4 fluorescence of NMVCM-encapsulated structures showed characteristic calcium transient waveforms that increased in magnitude and rate of decline during treatment with 100 nM isoproterenol. This novel instrumented 3D cardiac microtissue serves as a physiologically relevant in vitro model system with great potential for use in cardiac disease modeling and drug screening.

Rapid 3D bioprinting of in vitro cardiac tissue models using human embryonic stem cell-derived cardiomyocytes.

There is a great need for physiologically relevant 3D human cardiac scaffolds for both short-term, the development of drug testing platforms to screen new drugs across different genetic backgrounds, and longer term, the replacement of damaged or non-functional cardiac tissue after injury or infarction. In this study, we have designed and printed a variety of scaffolds for in vitro diagnostics using light based Micro-Continuous Optical Printing (µCOP). Human embryonic stem cell-derived cardiomyocyte (hESC-CMs) were directly printed into gelatin hydrogel on glass to determine their viability and ability to align. The incorporation of Green Fluorescent Protein/Calmodulin/M13 Peptide (GCaMP3)-hESC-CMs allowed the ability to continuously monitor calcium transients over time. Normalized fluorescence of GCaMP3-hESCCMs increased by 18 ± 6% and 40 ± 5% when treated with 500 nM and 1 µM of isoproterenol, respectively. Finally, GCaMP3-hESC-CMs were printed across a customizable 3D printed cantilever-based force system. Along with force tracking by visualizing the displacement of the cantilever, calcium transients could be observed in a non-destructive manner, allowing the samples to be examined over several days. Our µCOP-printed cardiac models presented here can be used as a powerful tool for drug screening and to analyze cardiac tissue maturation.

3D printed micro-scale force gauge arrays to improve human cardiac tissue maturation and enable high throughput drug testing.

Human induced pluripotent stem cell - derived cardiomyocytes (iPSC-CMs) are regarded as a promising cell source for establishing in-vitro personalized cardiac tissue models and developing therapeutics. However, analyzing cardiac force and drug response using mature human iPSC-CMs in a high-throughput format still remains a great challenge. Here we describe a rapid light-based 3D printing system for fabricating micro-scale force gauge arrays suitable for 24-well and 96-well plates that enable scalable tissue formation and measurement of cardiac force generation in human iPSC-CMs. We demonstrate consistent tissue band formation around the force gauge pillars with aligned sarcomeres. Among the different maturation treatment protocols we explored, 3D aligned cultures on force gauge arrays with in-culture pacing produced the highest expression of mature cardiac marker genes. We further demonstrated the utility of these micro-tissues to develop significantly increased contractile forces in response to treatment with isoproterenol, levosimendan, and omecamtiv mecarbil. Overall, this new 3D printing system allows for high flexibility in force gauge design and can be optimized to achieve miniaturization and promote cardiac tissue maturation with great potential for high-throughput in-vitro drug screening applications. STATEMENT OF SIGNIFICANCE: The application of iPSC-derived cardiac tissues in translatable drug screening is currently limited by the challenges in forming mature cardiac tissue and analyzing cardiac forces in a high-throughput format. We demonstrate the use of a rapid light-based 3D printing system to build a micro-scale force gauge array that enables scalable cardiac tissue formation from iPSC-CMs and measurement of contractile force development. With the capability to provide great flexibility over force gauge design as well as optimization to achieve miniaturization, our 3D printing system serves as a promising tool to build cardiac tissues for high-throughput in-vitro drug screening applications.

Ventilation perfusion single photon emission computed tomography: Referral practices and diagnosis of acute pulmonary embolism in the quaternary clinical setting.

INTRODUCTION: Ventilation perfusion single photon emission computed tomography (V/Q SPECT) and CTPA are the two leading imaging studies used to investigate acute pulmonary embolism. V/Q SPECT is often the first line investigation for pregnant patients and young females. Historically, V/Q Planar studies have high rates of indeterminate findings resulting in a preference for CTPA studies. The purpose of this research is to examine current V/Q SPECT referral practices in the quaternary clinical setting and to confirm V/Q SPECT studies have low rates of equivocal findings. METHODS: Retrospective study of a 6-month period of all completed V/Q SPECT studies (± LDCT) indicated for investigation of acute PE. V/Q SPECT studies were reported using the European Association of Nuclear Medicine guidelines. Patient demographic data and V/Q SPECT findings were recorded. CTPA and Doppler Ultrasound report findings were included if performed 48 hours prior to, or following V/Q SPECT study. Standard descriptive statistical analysis was undertaken. RESULTS: Ninety-nine percent of V/Q SPECT studies had reports positive or negative for acute PE, with 1% inconclusive. Twenty-two percent of patients had either CTPA or Doppler Ultrasound studies within a 48- hour period prior to, or following V/Q SPECT, with the majority having a negative Doppler ultrasound prior to negative V/Q SPECT. Sixty-eight percent of patients referred for V/Q SPECT were females under the age of 55, 40% of whom were pregnant. CONCLUSIONS: Ventilation perfusion single photon emission computed tomography has low rates of equivocal findings with referral practices indicating pregnant patients and young women are considered to most benefit from V/Q SPECT as a first line investigation for acute PE.

3D-Printing of Functional Biomedical Microdevices via Light- and Extrusion-Based Approaches.

3D-printing is a powerful additive manufacturing tool, one that enables fabrication of biomedical devices and systems that would otherwise be challenging to create with more traditional methods such as machining or molding. Many different classes of 3D-printing technologies exist, most notably extrusion-based and light-based 3D-printers, which are popular in consumer markets, with advantages and limitations for each modality. The focus here is primarily on showcasing the ability of these 3D-printing platforms to create different types of functional biomedical microdevices-their advantages and limitations are covered with respect to other classes of 3D-printing, as well as the past, recent, and future efforts to advance the functional microdevice domain. In particular, the fabrication of micromachines/robotics, drug-delivery devices, biosensors, and microfluidics is addressed. The current challenges associated with 3D-printing of functional microdevices are also addressed, as well as future directions to improve both the printing techniques and the performance of the printed products.

3D bioprinting of functional tissue models for personalized drug screening and in vitro disease modeling.

3D bioprinting is emerging as a promising technology for fabricating complex tissue constructs with tailored biological components and mechanical properties. Recent advances have enabled scientists to precisely position materials and cells to build functional tissue models for in vitro drug screening and disease modeling. This review presents state-of-the-art 3D bioprinting techniques and discusses the choice of cell source and biomaterials for building functional tissue models that can be used for personalized drug screening and disease modeling. In particular, we focus on 3D-bioprinted liver models, cardiac tissues, vascularized constructs, and cancer models for their promising applications in medical research, drug discovery, toxicology, and other pre-clinical studies.

SERS-enhanced piezoplasmonic graphene composite for biological and structural strain mapping.

Thin-film optical strain sensors have the ability to map small deformations with spatial and temporal resolution and do not require electrical interrogation. This paper describes the use of graphene decorated with metallic nanoislands for sensing of tensile deformations of less than 0.04% with a resolution of less than 0.002%. The nanoisland-graphene composite films contain gaps between the nanoislands, which when functionalized with benzenethiolate behave as hot spots for surface-enhanced Raman scattering (SERS). Mechanical strain increases the sizes of the gaps; this increase attenuates the electric field, and thus attenuates the SERS signal. This compounded, SERS-enhanced "piezoplasmonic" effect can be quantified using a plasmonic gauge factor, and is among the most sensitive mechanical sensors of any type. Since the graphene-nanoisland films are both conductive and optically active, they permit simultaneous electrical stimulation of myoblast cells and optical detection of the strains produced by the cellular contractions.

Assembling the dodo in early modern natural history.

This paper explores the assimilation of the flightless dodo into early modern natural history. The dodo was first described by Dutch sailors landing on Mauritius in 1598, and became extinct in the 1680s or 1690s. Despite this brief period of encounter, the bird was a popular subject in natural-history works and a range of other genres. The dodo will be used here as a counterexample to the historical narratives of taxonomic crisis and abrupt shifts in natural history caused by exotic creatures coming to Europe. Though this bird had a bizarre form, early modern naturalists integrated the dodo and other flightless birds through several levels of conceptual categorization, including the geographical, morphological and symbolic. Naturalists such as Charles L'Ecluse produced a set of typical descriptive tropes that helped make up the European dodo. These long-lived images were used for a variety of symbolic purposes, demonstrated by the depiction of the Dutch East India enterprise in Willem Piso's 1658 publication. The case of the dodo shows that, far from there being a dramatic shift away from emblematics in the seventeenth century, the implicit symbolic roles attributed to exotic beasts by naturalists constructing them from scant information and specimens remained integral to natural history.

The Prime Minister and the platypus: A paradox goes to war.

In February 1943, in the midst of the Second World War, Prime Minister Winston Churchill demanded that a live duck-billed platypus be sent from Australia to Britain. A vigorous male was shipped off but died shortly before arrival in Britain. This request can only be understood if placed in the context of Churchill's passion for exotic pets as well as the rich history of aristocratic menageries and live diplomatic gifts. Obtaining an animal hitherto unseen alive in Europe would have been a great zoological achievement for London Zoo and secured British authority in heated historical taxonomical debates. This zoological triumph, coupled with accomplishing an extravagant enterprise in the middle of war-time austerity would have boosted public morale. Most importantly, despite its death, the platypus, served as a token for mediating the soured relations between Australia and Britain. Churchill's platypus provides a unique case of animal collecting that incorporates effects on international diplomacy and public relations along with a great private eccentricity and passion.

Care of bereaved parents after sudden infant death.

About 340 infants die suddenly and unexpectedly in the UK every year (Foundation for the Study of Infant Deaths 2005a), and one of the recommendations made in the Bristol Royal Infirmary inquiry final report (Kennedy 2001) was that infants found dead or moribund at home must be taken to emergency departments (EDs) for attempted resuscitation or further investigation. Sudden and unexpected infant death is one of the most stressful events that ED staff can experience, however, and they often lack training in this area even though they are keen to undertake such preparation (Levetown 2004, Ross-Adjie et al 2007). This article therefore discusses the guidelines on providing bereavement care to parents and best practice in EDs.