Towards Establishing Best Practice in the Analysis of Hydrogen and Deuterium by Atom Probe Tomography.

As hydrogen is touted as a key player in the decarbonization of modern society, it is critical to enable quantitative hydrogen (H) analysis at high spatial resolution and, if possible, at the atomic scale. H has a known deleterious impact on the mechanical properties (strength, ductility, toughness) of most materials that can hinder their use as part of the infrastructure of a hydrogen-based economy. Enabling H mapping including local hydrogen concentration analyses at specific microstructural features is essential for understanding the multiple ways that H affect the properties of materials including embrittlement mechanisms and their synergies. In addition, spatial mapping and quantification of hydrogen isotopes is essential to accurately predict tritium inventory of future fusion power plants thus ensuring their safe and efficient operation. Atom probe tomography (APT) has the intrinsic capability to detect H and deuterium (D), and in principle the capacity for performing quantitative mapping of H within a material's microstructure. Yet, the accuracy and precision of H analysis by APT remain affected by complex field evaporation behavior and the influence of residual hydrogen from the ultrahigh vacuum chamber that can obscure the signal of H from within the material. The present article reports a summary of discussions at a focused workshop held at the Max-Planck Institute for Sustainable Materials in April 2024. The workshop was organized to pave the way to establishing best practices in reporting APT data for the analysis of H. We first summarize the key aspects of the intricacies of H analysis by APT and then propose a path for better reporting of the relevant data to support interpretation of APT-based H analysis in materials.

Development of a Smart Wireless Multisensor Platform for an Optogenetic Brain Implant.

Implantable cell replacement therapies promise to completely restore the function of neural structures, possibly changing how we currently perceive the onset of neurodegenerative diseases. One of the major clinical hurdles for the routine implementation of stem cell therapies is poor cell retention and survival, demanding the need to better understand these mechanisms while providing precise and scalable approaches to monitor these cell-based therapies in both pre-clinical and clinical scenarios. This poses significant multidisciplinary challenges regarding planning, defining the methodology and requirements, prototyping and different stages of testing. Aiming toward an optogenetic neural stem cell implant controlled by a smart wireless electronic frontend, we show how an iterative development methodology coupled with a modular design philosophy can mitigate some of these challenges. In this study, we present a miniaturized, wireless-controlled, modular multisensor platform with fully interfaced electronics featuring three different modules: an impedance analyzer, a potentiostat and an optical stimulator. We show the application of the platform for electrical impedance spectroscopy-based cell monitoring, optical stimulation to induce dopamine release from optogenetically modified neurons and a potentiostat for cyclic voltammetry and amperometric detection of dopamine release. The multisensor platform is designed to be used as an opto-electric headstage for future in vivo animal experiments.

Novel Conformation-Dependent Tau Antibodies Are Modulated by Adjacent Phosphorylation Sites.

Tau proteins within the adult central nervous system (CNS) are found to be abnormally aggregated into heterogeneous filaments in neurodegenerative diseases, termed tauopathies. These tau inclusions are pathological hallmarks of Alzheimer's disease (AD), Pick's disease (PiD), corticobasal degeneration (CBD), and progressive supranuclear palsy (PSP). The neuropathological hallmarks of these diseases burden several cell types within the CNS, and have also been shown to be abundantly phosphorylated. The mechanism(s) by which tau aggregates in the CNS is not fully known, but it is hypothesized that hyperphosphorylated tau may precede and further promote filament formation, leading to the production of these pathological inclusions. In the studies herein, we generated and thoroughly characterized two novel conformation-dependent tau monoclonal antibodies that bind to residues Pro218-Glu222, but are sensitive to denaturing conditions and highly modulated by adjacent downstream phosphorylation sites. These epitopes are present in the neuropathological hallmarks of several tauopathies, including AD, PiD, CBD, and PSP. These novel antibodies will further enable investigation of tau-dependent pathological inclusion formation and enhance our understanding of the phosphorylation signatures within tauopathies with the possibility of new biomarker developments.

Interferometric Constraints on Spacelike Coherent Rotational Fluctuations.

Precision measurements are reported of the cross-spectrum of rotationally induced differential position displacements in a pair of colocated 39 m long, high-power Michelson interferometers. One arm of each interferometer is bent 90° near its midpoint to obtain sensitivity to rotations about an axis normal to the plane of the instrument. The instrument achieves quantum-limited sensing of spatially correlated signals in a broad frequency band extending beyond the 3.9-MHz inverse light travel time of the apparatus. For stationary signals with bandwidth Δf>10 kHz, the sensitivity to rotation-induced strain h of classical or exotic origin surpasses CSD_{δh}

Hot punching for loading of biodegradable microcontainers with budesonide-Soluplus film.

Micro-reservoir based drug delivery systems have the potential to provide targeted drug release locally in the intestine, i.e. at the inflamed areas of the intestine of patients with inflammatory bowel disease (IBD). In this study, microcontainers with a diameter of 300 µm and a height of 100 µm, asymmetrical geometry and the possibility to provide unidirectional release, are fabricated in the biodegradable polymer poly-ɛ-caprolactone (PCL) using hot punching. As a first step towards local treatment of IBD, a novel method for loading of microcontainers with the corticosteroid budesonide is developed. For this purpose, a budesonide-Soluplus drug-polymer film is prepared by spin coating and loaded into the microcontainer reservoirs using hot punching. The processing parameters are optimized to achieve a complete loading of a large number of containers in a single step. A poly(lactic-co-glycolic acid) (PLGA) 50:50 lid is subsequently applied by spray coating. Solid-state characterization indicates that the drug is in an amorphous state in the drug-polymer films and the in vitro drug release profile showed a 68% release over 10 h. The results demonstrate that hot punching can be employed both as a production and loading method for PCL microcontainers with the perspective of local treatment of IBD.

Prediction of idiopathic pulmonary fibrosis progression using early quantitative changes on CT imaging for a short term of clinical 18-24-month follow-ups.

OBJECTIVE: High-resolution computed tomography (HRCT) plays an indispensable role in the diagnosis of idiopathic pulmonary fibrosis (IPF). Due to unpredictability in progression and the short median survival of 2-5 years, it is critical to delineate the patients with rapid progression. The aim is to evaluate the predictability of IPF progression using the early quantitative changes. METHODS: Automated texture-based quantitative lung fibrosis (QLF) was calculated from the anonymized HRCT. Two datasets were collected retrospectively: (1) a pilot study of 35 subjects with three sequential scans (baseline and 6 and 12 months) to obtain a threshold, where visual assessments were stable at 6 months but worsened at 12 months; (2) 157 independent subjects to test the threshold. Landmark Cox regressions were used to compare the progression-free survival (PFS) defined by pulmonary function using the threshold from the early changes in QLF. C-indexes were reported as estimations of the concordance of prediction. RESULTS: A threshold of 4% QLF change at 6 months corresponded to the mean change that worsened on HRCT visually at 12 months from the pilot study. Using the threshold, significant differences were found in the independent dataset (hazard ratio (HZ) = 5.92, p = 0.001 by Cox model, C-index = 0.71 at the most severe lobe; and HZ = 3.22, p = 0.012, C-index = 0.68 in the whole lung). Median PFS was 11.9 months for subjects with ≥ 4% changes, whereas median PFS was greater than 18 months for subjects with < 4% changes at the most severe lobe. CONCLUSION: Early structural changes on HRCT using a quantitative score can predict progression in lung function. KEY POINTS: • Changes on HRCT using quantitative texture-based scores can play a pivotal role for providing information and an aid tool for timely management decision for patients with IPF. • Quantitative changes on HRCT of 4% or more, which matched 6-month prior changes with visual assessment of worsening, can play a pivotal role for providing prediction of clinical progression by 3-5 folds higher in the next incidence, compared with those of subjects with less than 4% changes. • Early structural changes of 4% or more in a paired HRCT scans derived by quantitative scores can predict the progression in lung function in 1-2 years in subjects with IPF, which is critical information for timely management decision for subjects with IPF where the median survival is 2 to 5 years.

Simulation and calibration of a compact millimeter-wavelength Fourier transform spectrometer.

This paper presents the simulation and calibration of a Fourier transform spectrometer (FTS) developed to measure the spectrum of radiation sources between 50 GHz and 330 GHz, such as the cosmic microwave background. The recorded signal is modified from the ideal by properties of the interferometer and the detection system. We have developed a ray-trace-based simulation with which we can model these effects. The model can be verified with measurements and used to understand the instrument's systematic effects and to design new optimized configurations. The optimization comprises parameters of the design, such as large étendu, maximal spectral resolution, compact size, operational simplicity, and light weight, that conflict and need to be balanced. The numerical simulation consists of two parts: time-stream signal analysis and a ray-trace-based simulation that includes polarization and path length calculations and can account for the effects of beam loss and change of focus as the delay-generating mirror travels on its path. The simulation can study the coherence level and frequency resolution of the FTS instrument. While not exercised in this study, the simulation also can be used to study the effect of mirror figure and polarizer non-idealities, walk-off rays in the beam due to the large étendu, as well as misalignment of optical elements. We then present the comparison between simulations of a spectrally unresolved source and measurements by the FTS.

Compact millimeter-wavelength Fourier-transform spectrometer.

We have constructed a Fourier-transform spectrometer (FTS) operating between 50 GHz and 330 GHz with minimum volume (355×260×64 mm) and weight (5.9 kg) while maximizing optical throughput (100 mm2 sr) and optimizing the spectral resolution (4 GHz). This FTS is designed as a polarizing Martin-Puplett interferometer with unobstructed input and output in which both input polarizations undergo interference. The instrument construction is simple with mirrors milled on the box walls and one motorized stage as the single moving element. We characterize the performance of the FTS, compare the measurements to an optical simulation, and discuss features that relate to details of the FTS design. The simulation is also used to determine the tolerance of optical alignments for the required specifications. We detail the FTS mechanical design and provide the control software as well as the analysis code online.

First Measurements of High Frequency Cross-Spectra from a Pair of Large Michelson Interferometers.

Measurements are reported of the cross-correlation of spectra of differential position signals from the Fermilab Holometer, a pair of colocated 39 m long, high power Michelson interferometers with flat broadband frequency response in the MHz range. The instrument obtains sensitivity to high frequency correlated signals far exceeding any previous measurement in a broad frequency band extending beyond the 3.8 MHz inverse light-crossing time of the apparatus. The dominant but uncorrelated shot noise is averaged down over 2×10^{8} independent spectral measurements with 381 Hz frequency resolution to obtain 2.1×10^{-20}m/sqrt[Hz] sensitivity to stationary signals. For signal bandwidths Δf>11 kHz, the sensitivity to strain h or shear power spectral density of classical or exotic origin surpasses a milestone PSD_{δh}

Nanomechanical Pyrolytic Carbon Resonators: Novel Fabrication Method and Characterization of Mechanical Properties.

Micro- and nanomechanical string resonators, which essentially are highly stressed bridges, are of particular interest for micro- and nanomechanical sensing because they exhibit resonant behavior with exceptionally high quality factors. Here, we fabricated and characterized nanomechanical pyrolytic carbon resonators (strings and cantilevers) obtained through pyrolysis of photoresist precursors. The developed fabrication process consists of only three processing steps: photolithography, dry etching and pyrolysis. Two different fabrication strategies with two different photoresists, namely SU-8 2005 (negative) and AZ 5214e (positive), were compared. The resonant behavior of the pyrolytic resonators was characterized at room temperature and in high vacuum using a laser Doppler vibrometer. The experimental data was used to estimate the Young's modulus of pyrolytic carbon and the tensile stress in the string resonators. The Young's moduli were calculated to be 74 ± 8 GPa with SU-8 and 115 ± 8 GPa with AZ 5214e as the precursor. The tensile stress in the string resonators was 33 ± 7 MPa with AZ 5214e as the precursor. The string resonators displayed maximal quality factor values of up to 3000 for 525-µm-long structures.

[Acute treatment of patients with severe traumatic brain injury]. / Akutversorgung des Patienten mit schwerem Schädel-Hirn-Trauma.

BACKGROUND: Traumatic brain injury (TBI) is a leading cause of death and permanent disability and a common and important global problem. The contribution of secondary posttraumatic brain damage to overall disability in TBI is significant, underlining the importance of prompt and comprehensive treatment for affected patients. METHODS: This article focuses on current concepts of prehospital and emergency room management of patients with severe TBI to prevent secondary brain injuries. RESULTS AND DISCUSSION: Preclinical prevention and treatment of hypoxia, hypotension and hypercarbia are essential, as they affect the long-term outcome in TBI patients. Prehospital intubation should be critically weighed and in the context of an individual decision. In general, prehospital intubation is more difficult than in the clinical setting. The combination of ketamine and benzodiazepines are commonly used to induce anesthesia before intubation in hemodynamic instable patients. The choice of a muscle relaxant for anesthesia induction is either a non-depolarizing neuromuscular blocking agent or succinylcholine. Administration of mannitol or hypertonic saline is effective to rapidly decrease intracranial pressure. Whenever possible the final destination for transport of TBI patients should be a level I center with round the clock neurosurgical expertise. Trauma-induced coagulopathy should be recognized and immediately treated using a point-of-care testing. CONCLUSION: Hypoxia, hypotension and hypercarbia should strictly be avoided to improve survival and neurological outcome in patients with severe TBI. The prehospital decision to intubate must be made on a case by case basis at the accident site. A level I trauma center should be the destination for this patient group.

Targeting adipose tissue via systemic gene therapy.

Adipose tissue has a critical role in energy and metabolic homeostasis, but it is challenging to adapt techniques to modulate adipose function in vivo. Here we develop an in vivo, systemic method of gene transfer specifically targeting adipose tissue using adeno-associated virus (AAV) vectors. We constructed AAV vectors containing cytomegalovirus promoter-regulated reporter genes, intravenously injected adult mice with vectors using multiple AAV serotypes, and determined that AAV2/8 best targeted adipose tissue. Altering vectors to contain adiponectin promoter/enhancer elements and liver-specific microRNA-122 target sites restricted reporter gene expression to adipose tissue. As proof of efficacy, the leptin gene was incorporated into the adipose-targeted expression vector, package into AAV2/8 and administered intravenously to 9- to 10-week-old ob/ob mice. Phenotypic changes were measured over an 8-week period. Leptin mRNA and protein were expressed in adipose and leptin protein was secreted into plasma. Mice responded with reversal of weight gain, decreased hyperinsulinemia and improved glucose tolerance. AAV2/8-mediated systemic delivery of an adipose-targeted expression vector can replace a gene lacking in adipose tissue and correct a mouse model of human disease, demonstrating experimental application and therapeutic potential in disorders of adipose.

Measurement of total occlusal convergence of 3 different tooth preparations in 4 different planes by dental students.

STATEMENT OF PROBLEM: Total occlusal convergence of crown preparation is an important didactic and clinical concept in dental education. PURPOSE: The purpose of this study was to compare the discrepancy between the total occlusal convergence of dental students' typodont crown preparations and the ideal range (4 to 10 degrees) in 3 different regions of the mouth and in 4 different planes of the teeth. MATERIAL AND METHODS: The dental students of the Class of 2012 at Harvard School of Dental Medicine were asked to prepare typodont teeth for crowns on 3 different teeth, the maxillary left central incisor (ceramic), mandibular left first molar (complete metal), and mandibular left first premolar (metal ceramic), during their third year preclinical summative examination and the Comprehensive Clinical Examination in their fourth year. Eighteen students prepared 3 teeth in their third and fourth years, whereas 19 students participated only in their fourth year, for a total of 55 sets of 3 teeth. By using custom fit die bases to reproduce the position, a novel procedure of measuring each tooth was accomplished in 4 different planes: the faciolingual, mesiodistal, mesiofacial-distolingual, and mesiolingual-distofacial. The total occlusal convergence of each image was measured with a computer screen protractor. The gingival 2 mm of the axial wall was used to determine the taper of each wall. Linear mixed model analysis was used to estimate and compare the total occlusal convergences of different teeth and planes (α=.05). Bonferroni corrections were used to adjust for post hoc multiple comparisons. RESULTS: The mean total occlusal convergence varied by tooth and plane (2-way interaction; P<.001). For the first molar, dental students excessively tapered in all 4 planes; the model-predicted 99% CIs for the total occlusal convergence were as follows: faciolingual (12.7, 19.4), mesiodistal (14.0, 19.3), mesiofacial-distolingual (13,4, 19.4), and mesiolingual-distofacial (13.7, 19.1). For the central incisor, 99% CIs for the total occlusal convergence were (15.9, 24.4) for the faciolingual measurement, providing strong evidence of excessive tapering, and (4.1, 8.0) for the mesiodistal measurement, which was within the ideal total occlusal convergence range. The mesiofacial-distolingual and mesiolingual-distofacial planes in the central incisor and all 4 planes in the first premolar had mean total occlusal convergences that exceeded 10 degrees; however, excessive tapering could not be statistically established, because their CIs included values within the ideal range. CONCLUSIONS: The present study found significant evidence of excessive tapering in a study comparing the total occlusal convergence values of crown preparations with those of the ideal preparation for 3 different teeth in 4 different planes. The total occlusal convergence for the molar preparations had the highest mean values.

Biomaterial-based scaffolds for direct in situ programming of tumor-infiltrating T lymphocytes.

Adoptive cell therapy with tumor-infiltrating T cells (TILs) has generated exciting clinical trial results for the treatment of unresectable solid tumors. However, solid tumors remain difficult targets for adoptively transferred T cells, due in part to poor migration of TILs to the tumor, physical barriers to infiltration, and active suppression of TILs by the tumor. Furthermore, a highly skilled team is required to obtain tumor tissue, isolate and expand the TILs ex vivo, and reinfuse them into the patient, which drives up costs and limits patient access. Here, we describe a cell-free polymer implant designed to recruit, genetically reprogram and expand host T cells at tumor lesions in situ. Importantly, the scaffold can be fabricated on a large scale and is stable to lyophilization. Using a mouse breast cancer model, we show that the implants quickly and efficiently amass cancer-specific host lymphocytes at the tumor site in quantities sufficient to bring about long-term tumor regression. Given that surgical care is the mainstay of cancer treatment for many patients, this technology could be easily implemented in a clinical setting as an add-on to surgery for solid tumors. Furthermore, the approach could be broadened to recruit and genetically reprogram other therapeutically desirable host cells, such as macrophages, natural killer cells or dendritic cells, potentially boosting the antitumor effectiveness of the implant even more.

Liquid foam improves potency and safety of gene therapy vectors.

Interest in gene therapy medicines is intensifying as the first wave of gene-correcting drugs is now reaching patient populations. However, efficacy and safety concerns, laborious manufacturing protocols, and the high cost of the therapeutics are still significant barriers in gene therapy. Here we describe liquid foam as a vehicle for gene delivery. We demonstrate that embedding gene therapy vectors (nonviral or viral) in a methylcellulose/xanthan gum-based foam formulation substantially boosts gene transfection efficiencies in situ, compared to liquid-based gene delivery. We further establish that our gene therapy foam is nontoxic and retained at the intended target tissue, thus minimizing both systemic exposure and targeting of irrelevant cell types. The foam can be applied locally or injected to fill body cavities so the vector is uniformly dispersed over a large surface area. Our technology may provide a safe, facile and broadly applicable option in a variety of clinical settings.

Interventional Treatment of Symptomatic Vasospasm in the Setting of Traumatic Brain Injury: A Systematic Review of Reported Cases.

Traumatic subarachnoid hemorrhage (tSAH) is frequently comorbid with traumatic brain injury (TBI) and may induce secondary injury through vascular changes such as vasospasm and subsequent delayed cerebral ischemia (DCI). While aneurysmal SAH is well studied regarding vasospasm and DCI, less is known regarding tSAH and the prevalence of vasospasm and DCI, the consequences of vasospasm in this setting, when treatment is indicated, and which management strategies should be implemented. In this article, a systematic review of the literature that was conducted for cases of symptomatic vasospasm in patients with TBI is reported, association with tSAH is reported, risk factors for vasospasm and DCI are summarized, and commonalities in diagnosis and management are discussed. Clinical characteristics and treatment outcomes of 38 cases across 20 studies were identified in which patients with TBI with vasospasm underwent medical or endovascular management. Of the patients with data available for each category, the average age was 48.7 ± 20.3 years (n = 31), the Glasgow Coma Scale score at presentation was 10.6 ± 4.5 (n = 35), and 100% had tSAH (n = 29). Symptomatic vasospasm indicative of DCI was diagnosed on average at postinjury day 8.4 ± 3.0 days (n = 30). Of the patients, 56.6% (n = 30) had a new ischemic change associated with vasospasm confirming DCI. Treatment strategies are discussed, with 11 of 12 endovascularly treated and 19 of 26 medically treated patients surviving to discharge. tSAH is associated with vasospasm and DCI in moderate and severe TBI, and patients with clinical and radiographic evidence of symptomatic vasospasm and subsequent DCI may benefit from endovascular or medical management strategies.

Process optimization of ultrasonic spray coating of polymer films.

In this work we have performed a detailed study of the influence of various parameters on spray coating of polymer films. Our aim is to produce polymer films of uniform thickness (500 nm to 1 µm) and low roughness compared to the film thickness. The coatings are characterized with respect to thickness, roughness (profilometer), and morphology (optical microscopy). Polyvinylpyrrolidone (PVP) is used to do a full factorial design of experiments with selected process parameters such as temperature, distance between spray nozzle and substrate, and speed of the spray nozzle. A mathematical model is developed for statistical analysis which identifies the distance between nozzle and substrate as the most significant parameter. Depending on the drying of the sprayed droplets on the substrate, we define two broad regimes, "dry" and "wet". The optimum condition of spraying lies in a narrow window between these two regimes, where we obtain a film of desired quality. Both with increasing nozzle-substrate distance and temperature, the deposition moves from a wet state to a dry regime. Similar results are also achieved for solvents with low boiling points. Finally, we study film formation during spray coating with poly (D,L-lactide) (PDLLA). The results confirm the processing knowledge obtained with PVP and indicate that the observed trends are identical for spraying of other polymer films.

The etiology of severe acute gastroenteritis among adults visiting emergency departments in the United States.

BACKGROUND: Acute gastroenteritis (AGE) remains a common cause of clinic visits and hospitalizations in the United States, but the etiology is rarely determined. METHODS: We performed a prospective, multicenter emergency department-based study of adults with AGE. Subjects were interviewed on presentation and 3-4 weeks later. Serum samples, rectal swab specimens, and/or whole stool specimens were collected at presentation, and serum was collected 3-4 weeks later. Fecal specimens were tested for a comprehensive panel of viral, bacterial, and parasitic pathogens; serum was tested for calicivirus antibodies. RESULTS: Pathogens were detected in 25% of 364 subjects, including 49% who provided a whole stool specimen. The most commonly detected pathogens were norovirus (26%), rotavirus (18%), and Salmonella species (5.3%). Pathogens were detected significantly more often from whole stool samples versus a rectal swab specimen alone. Nine percent of subjects who provided whole stool samples had >1 pathogen identified. CONCLUSIONS: Viruses, especially noroviruses, play a major role as agents of severe diarrhea in adults. Further studies to confirm the unexpectedly high prevalence of rotaviruses and to explore the causes of illness among patients from whom a pathogen cannot be determined are needed. Studies of enteric pathogens should require the collection of whole stool samples.

Updated trends in percutaneous renal arteriography among radiologists and other specialties.

PURPOSE: Prior studies have demonstrated an overall decline in percutaneous renal artery angioplasty with and without stenting from 1988 to 2009. We evaluated the recent utilization trends in percutaneous renal arteriography (PTRA) among radiologists and non-radiologist providers from 2010 to 2018. METHODS: Data from the 2010-2018 nationwide Medicare Part B fee-for-service database were used to tabulate case volumes for PTRA. Annual utilization rates per 10,000 Medicare beneficiaries were calculated and aggregated based on physician specialty: radiologists, cardiologists, vascular surgeons, general surgeons, or others. RESULTS: From 2010 to 2018, the overall utilization rate of PTRA markedly declined (-72% change; from 15.5 to 4.3 cases per 10,000 Medicare beneficiaries). Proportionally, the cardiologist share of PTRA saw the greatest decline, falling from 74% market share in 2010 (11.4/15.5 cases) to only 36% market share in 2018 (1.6/4.3 cases). The market share of PTRA performed by radiologists grew from 12% market share in 2010 (1.9/15.5 cases) to 28% in 2018 (1.2/4.3 cases); despite this, the absolute number of PTRA performed by radiologists saw a smaller decline over this period (-34%; 1.9 to 1.2 cases). CONCLUSION: The total utilization rates of PTRA in the Medicare population has continued to decline from 2010 to 2018, likely due to clinical trials suggesting limited efficacy of angioplasty and stenting in the treatment of renovascular hypertension and other factors such as declining reimbursement. The overall and per-specialty rates continue to decline, reflecting an overarching trend away from procedural management of renovascular hypertension.

Modular 3D printed platform for fluidically connected human brain organoid culture.

Brain organoid technology has transformed both basic and applied biomedical research and paved the way for novel insights into developmental processes and disease states of the human brain. While the use of brain organoids has been rapidly growing in the past decade, the accompanying bioengineering and biofabrication solutions have remained scarce. As a result, most brain organoid protocols still rely on commercially available tools and culturing platforms that had previously been established for different purposes, thus entailing suboptimal culturing conditions and excessive use of plasticware. To address these issues, we developed a 3D printing pipeline for the fabrication of tailor-made culturing platforms for fluidically connected but spatially separated brain organoid array culture. This all-in-one platform allows all culturing steps-from cellular aggregation, spheroid growth, hydrogel embedding, and organoid maturation-to be performed in a single well plate without the need for organoid manipulation or transfer. Importantly, the approach relies on accessible materials and widely available 3D printing equipment. Furthermore, the developed design principles are modular and highly customizable. As such, we believe that the presented technology can be easily adapted by other research groups and fuel further development of culturing tools and platforms for brain organoids and other 3D cellular systems.