Carbonized Polymer for Joule Heating Processing Towards Biosensor Development.

This paper presents the experimental findings towards developing carbonized microelectrodes using a Joule heating process within a temperature window that is compatible with CMOS. Bridge-on-pillars polymer structures have been 3D-printed using two-photon polymerization (2PP). They have been annealed in various processing conditions to increase the fraction of carbon in the precursor material and to achieve appreciable electric conductivity so that they can be used to drive current to enable Joule heating. To evaluate the outcome of the processing sequences, Raman spectroscopy has been performed to assess the degree of carbonization. Such CMOS-compatible carbon electrodes are important for monolithic, low-cost biosensor development.Clinical relevance- This establishes the potential of carbonized polymer electrode for low-cost, CMOS-compatible monolithic biosensor platform for implementation in medical diagnosis and treatment.

A Wireless Time-Scaling Chaotic Shift Keying Encryption System For Biosensing Systems.

This work presents a wireless time-scaling chaotic shift keying encryption system that can be used in wireless body area network applications. In wireless sensor nodes, the communication protocol being used provides some security measures and is implemented in software. However, no additional security measures are usually implemented. This paper demonstrates a discrete level real time encryption system using analog circuitry on a printed circuit board. The encryption system uses op amps, multipliers and resistors to implement the encryption. To implement wireless capabilities, commercial wireless microcontrollers using Bluetooth Low Energy were added, and a custom Bluetooth Low Energy profile was created to stream the analog encrypted signal.Clinical relevance- This work demonstrates an encryption system for wireless sensor devices for improved protection of private health information.

Temporal profiling of therapy resistance in human medulloblastoma identifies novel targetable drivers of recurrence.

Medulloblastoma (MB) remains a leading cause of cancer-related mortality among children. The paucity of MB samples collected at relapse has hindered the functional understanding of molecular mechanisms driving therapy failure. New models capable of accurately recapitulating tumor progression in response to conventional therapeutic interventions are urgently needed. In this study, we developed a therapy-adapted PDX MB model that has a distinct advantage of generating human MB recurrence. The comparative gene expression analysis of MB cells collected throughout therapy led to identification of genes specifically up-regulated after therapy, including one previously undescribed in the setting of brain tumors, bactericidal/permeability-increasing fold-containing family B member 4 (BPIFB4). Subsequent functional validation resulted in a markedly diminished in vitro proliferation, self-renewal, and longevity of MB cells, translating into extended survival and reduced tumor burden in vivo. Targeting endothelial nitric oxide synthase, a downstream substrate of BPIFB4, impeded growth of several patient-derived MB lines at low nanomolar concentrations.

A Combined pH-Impedance System Suitable for Portable Continuous Sensing.

In this paper, a combined pH and impedance sensing system suitable for portable measurements is presented. The sensor outputs are converted directly to frequency or pulse width. The pH sensor is based on a voltage clamp topology that uses charging and discharging capacitors, voltage window comparators, and an SR-Latch to convert the output to frequency. The impedance to frequency sensor is based on current and voltage comparators and an SR-Latch. The pH system based on ISFET transistors is experimentally verified with on chip electrodes while the impedance sensor is characterized with discrete electronic components. The portable system is implemented with two chips and an external multi-electrode array into a portable system. Resistance, capacitance, and pH are experimentally measured using buffer solutions to simulate a water quality monitoring application. The system is implemented in a portable format and all modules, excluding the commercial microprocessor, consume an average power of 56 µW with an area of 0.006 mm 2 using a 180 nm technology.

A Wearable CMOS Impedance to Frequency Sensing System for Non-Invasive Impedance Measurements.

In this paper, we demonstrate a novel non-invasive, wearable impedance sensor. The impedance sensor, using an impedance to frequency measurement, with two modes of resistance and capacitance measurement is implemented in CMOS 130 nm technology. The sensor consisting of current and voltage comparators for different mode of measurement, has a low power consumption of 30 µW per channel. The sensor is demonstrated in two applications, thoracic impedance and hand gesture recognition. Thoracic impedance is based on impedance modulation through fluid accumulation. Hand gestures are detected through tissue impedance sensing. The full thoracic impedance sensing system is smaller than a credit card, low cost, and consumes 3 mW which includes the sensor, transmitter, and power control unit. Data received by this sensor can be easily transferred for further processing and, eventually, detection of heart failure. The electrodes were implemented using conductive paint, and the system was validated using passive loads to represent human tissue models and test subjects. The hand gesture system operates on 600  µW with the maximum number of electrodes, and uses adhesive copper with electrical paint as electrodes.

The Rational Development of CD133-Targeting Immunotherapies for Glioblastoma.

CD133 marks self-renewing cancer stem cells (CSCs) in a variety of solid tumors, and CD133+ tumor-initiating cells are known markers of chemo- and radio-resistance in multiple aggressive cancers, including glioblastoma (GBM), that may drive intra-tumoral heterogeneity. Here, we report three immunotherapeutic modalities based on a human anti-CD133 antibody fragment that targets a unique epitope present in glycosylated and non-glycosylated CD133 and studied their effects on targeting CD133+ cells in patient-derived models of GBM. We generated an immunoglobulin G (IgG) (RW03-IgG), a dual-antigen T cell engager (DATE), and a CD133-specific chimeric antigen receptor T cell (CAR-T): CART133. All three showed activity against patient-derived CD133+ GBM cells, and CART133 cells demonstrated superior efficacy in patient-derived GBM xenograft models without causing adverse effects on normal CD133+ hematopoietic stem cells in humanized CD34+ mice. Thus, CART133 cells may be a therapeutically tractable strategy to target CD133+ CSCs in human GBM or other treatment-resistant primary cancers.

Wearables for the Next Pandemic.

This paper reviews the current state of the art in wearable sensors, including current challenges, that can alleviate the loads on hospitals and medical centers. During the COVID-19 Pandemic in 2020, healthcare systems were overwhelmed by people with mild to severe symptoms needing care. A careful study of pandemics and their symptoms in the past 100 years reveals common traits that should be monitored for managing the health and economic costs. Cheap, low power, and portable multi-modal-sensors that detect the common symptoms can be stockpiled and ready for the next pandemic. These sensors include temperature sensors for fever monitoring, pulse oximetry sensors for blood oxygen levels, impedance sensors for thoracic impedance, and other state sensors that can be integrated into a single system and connected to a smartphone or data center. Both research and commercial medically approved devices are reviewed with an emphasis on the electronics required to realize the sensing. The performance characteristics, such as accuracy, power, resolution, and size of each sensor modality are critically examined. A discussion of the characteristics, research challenges, and features of an ideal integrated wearable system is also presented.

CMOS based whole cell impedance sensing: Challenges and future outlook.

With the increasing need for multi-analyte point-of-care diagnosis devices, cell impedance measurement is a promising technique for integration with other sensing modalities. In this comprehensive review, the theory underlying cell impedance sensing, including the history, complementary metal-oxide-semiconductor (CMOS) based implementations, and applications are critically assessed. Whole cell impedance sensing, also known as electric cell-substrate impedance sensing (ECIS) or electrical impedance spectroscopy (EIS), is an approach for studying and diagnosing living cells in in-vitro and in-vivo environments. The technique is popular since it is label-free, non-invasive, and low cost when compared to standard biochemical assays. CMOS cell impedance measurement systems have been focused on expanding their applications to numerous aspects of biological, environmental, and food safety applications. This paper presents and evaluates circuit topologies for whole cell impedance measurement. The presented review compares several existing CMOS designs, including the classification, measurement speed, and sensitivity of varying topologies.

Bmi1 regulates human glioblastoma stem cells through activation of differential gene networks in CD133+ brain tumor initiating cells.

PURPOSE: Glioblastoma (GBM) is the most aggressive adult brain cancer, with a 15 month median survivorship attributed to the existence of treatment-refractory brain tumor initiating cells (BTICs). In order to better understand the mechanisms regulating the tumorigenic properties of this population, we studied the role of the polycomb group member BMI1 in our patient-derived GBM BTICs and its relationship with CD133, a well-established marker of BTICs. METHODS: Using gain and loss-of-function studies for Bmi1 in neural stem cells (NSCs) and patient-derived GBM BTICs respectively, we assessed in vitro self-renewal and in vivo tumor formation in these two cell populations. We further explored the BMI1 transcriptional regulatory network through RNA sequencing of different GBM BTIC populations that were knocked down for Bmi1. RESULTS: There is a differential role of BMI1 in CD133-positive cells, notably involving cell metabolism. In addition, we identified pivotal targets downstream of BMI1 in CD133+ cells such as integrin alpha 2 (ITGA2), that may contribute to regulating GBM stem cell properties. CONCLUSIONS: Our work sheds light on the association of three genes with CD133-BMI1 circuitry, their importance as downstream effectors of the BMI1 signalling pathway, and their potential as future targets for tackling GBM treatment-resistant cell populations.

BMI1 is a therapeutic target in recurrent medulloblastoma.

Medulloblastoma (MB) is the most frequent malignant pediatric brain tumor, representing 20% of newly diagnosed childhood central nervous system malignancies. Although advances in multimodal therapy yielded a 5-year survivorship of 80%, MB still accounts for the leading cause of childhood cancer mortality. In this work, we describe the epigenetic regulator BMI1 as a novel therapeutic target for the treatment of recurrent human Group 3 MB, a childhood brain tumor for which there is virtually no treatment option beyond palliation. Current clinical trials for recurrent MB patients based on genomic profiles of primary, treatment-naive tumors will provide limited clinical benefit since recurrent metastatic MBs are highly genetically divergent from their primary tumor. Using a small molecule inhibitor against BMI1, PTC-028, we were able to demonstrate complete ablation of self-renewal of MB stem cells in vitro. When administered to mice xenografted with patient tumors, we observed significant reduction in tumor burden in both local and metastatic compartments and subsequent increased survival, without neurotoxicity. Strikingly, serial in vivo re-transplantation assays demonstrated a marked reduction in tumor initiation ability of recurrent MB cells upon re-transplantation of PTC-028-treated cells into secondary recipient mouse brains. As Group 3 MB is often metastatic and uniformly fatal at recurrence, with no current or planned trials of targeted therapy, an efficacious targeted agent would be rapidly transitioned to clinical trials.

Therapeutic Targeting of the Premetastatic Stage in Human Lung-to-Brain Metastasis.

Brain metastases (BM) result from the spread of primary tumors to the brain and are a leading cause of cancer mortality in adults. Secondary tissue colonization remains the main bottleneck in metastatic development, yet this "premetastatic" stage of the metastatic cascade, when primary tumor cells cross the blood-brain barrier and seed the brain before initiating a secondary tumor, remains poorly characterized. Current studies rely on specimens from fully developed macrometastases to identify therapeutic options in cancer treatment, overlooking the potentially more treatable "premetastatic" phase when colonizing cancer cells could be targeted before they initiate the secondary brain tumor. Here we use our established brain metastasis initiating cell (BMIC) models and gene expression analyses to characterize premetastasis in human lung-to-BM. Premetastatic BMIC engaged invasive and epithelial developmental mechanisms while simultaneously impeding proliferation and apoptosis. We identified the dopamine agonist apomorphine to be a potential premetastasis-targeting drug. In vivo treatment with apomorphine prevented BM formation, potentially by targeting premetastasis-associated genes KIF16B, SEPW1, and TESK2 Low expression of these genes was associated with poor survival of patients with lung adenocarcinoma. These results illuminate the cellular and molecular dynamics of premetastasis, which is subclinical and currently impossible to identify or interrogate in human patients with BM. These data present several novel therapeutic targets and associated pathways to prevent BM initiation.Significance: These findings unveil molecular features of the premetastatic stage of lung-to-brain metastases and offer a potential therapeutic strategy to prevent brain metastases. Cancer Res; 78(17); 5124-34. ©2018 AACR.

Carbon nanospikes for biosensing applications.

In this paper, we discuss the structure and characteristics of carbon nanospikes. We also compare carbon nanospikes with previously grown carbon nanostructures known as vertically aligned carbon nanofibers (VACNF). Plasma enhanced chemical vapor deposition (PECVD) is used to fabricate both the nanospikes and VACNF. However, carbon nanospikes do not require a catalyst for the growth process, whereas VACNF requires a catalyst in the growth process. This facilitates batch fabrication with greater reproducibility. Scanning electron microscope images and Raman spectroscopy show that carbon nanospikes fabricated on silver wires will show superior performance.

RNAi screen identifies essential regulators of human brain metastasis-initiating cells.

Brain metastases (BM) are the most common brain tumor in adults and are a leading cause of cancer mortality. Metastatic lesions contain subclones derived from their primary lesion, yet their functional characterization is limited by a paucity of preclinical models accurately recapitulating the metastatic cascade, emphasizing the need for a novel approach to BM and their treatment. We identified a unique subset of stem-like cells from primary human patient brain metastases, termed brain metastasis-initiating cells (BMICs). We now establish a BMIC patient-derived xenotransplantation (PDXT) model as an investigative tool to comprehensively interrogate human BM. Using both in vitro and in vivo RNA interference screens of these BMIC models, we identified SPOCK1 and TWIST2 as essential BMIC regulators. SPOCK1 in particular is a novel regulator of BMIC self-renewal, modulating tumor initiation and metastasis from the lung to the brain. A prospective cohort of primary lung cancer specimens showed that SPOCK1 was overexpressed only in patients who ultimately developed BM. Protein-protein interaction network mapping between SPOCK1 and TWIST2 identified novel pathway interactors with significant prognostic value in lung cancer patients. Of these genes, INHBA, a TGF-ß ligand found mutated in lung adenocarcinoma, showed reduced expression in BMICs with knockdown of SPOCK1. In conclusion, we have developed a useful preclinical model of BM, which has served to identify novel putative BMIC regulators, presenting potential therapeutic targets that block the metastatic process, and transform a uniformly fatal systemic disease into a locally controlled and eminently more treatable one.

The identification of human pituitary adenoma-initiating cells.

Classified as benign central nervous system (CNS) tumors, pituitary adenomas account for 10% of diagnosed intracranial neoplasms. Although surgery is often curative, patients with invasive macroadenomas continue to experience significant morbidity and are prone to tumor recurrence. Given the identification of human brain tumor-initiating cells (TICs) that initiate and maintain tumor growth while promoting disease progression and relapse in multiple CNS tumors, we investigated whether TICs also drive the growth of human pituitary adenomas. Using a nanoString-based 80-gene custom codeset specific for developmental pathways, we identified a differential stem cell gene expression profile within human pituitary adenomas. Prospective functional characterization of stem cell properties in patient-derived adenomas representing all hormonal subtypes yielded a subtype-dependent self-renewal profile, which was enriched within the CD15+ cell fraction. The tumor-initiating capacity of CD15high adenoma cells was assayed in comparison to CD15low adenomas using in vivo limiting dilutions, which maintained the rare frequency of TICs. Repeated analyses using sorted cell populations for CD15+ TICs compared to CD15- adenoma cells provided further evidence of xenograft tumor formation to support CD15+ cells as putative pituitary adenoma-initiating cells (PAICs). The clinical utility of our findings was established through in silico analyses and comparative gene expression profiling of primary and recurrent pituitary adenomas. CD15 was enriched in recurrent adenomas, which was validated using routine clinical immunohistochemistry in a limited number of samples. Our work reports the first prospective identification of human PAICs using CD15. Patients with CD15high adenomas may therefore benefit from more aggressive surgical interventions and chemo/radiotherapy.

Development of a Patient-Derived Xenograft Model Using Brain Tumor Stem Cell Systems to Study Cancer.

Patient-derived xenograft (PDX) models provide an excellent platform to understand cancer initiation and development in vivo. In the context of brain tumor initiating cells (BTICs), PDX models allow for characterization of tumor formation, growth, and recurrence, in a clinically relevant in vivo system. Here, we detail procedures to harvest, culture, characterize, and orthotopically inject human BTICs derived from patient samples.

A Glucose Biosensor Using CMOS Potentiostat and Vertically Aligned Carbon Nanofibers.

This paper reports a linear, low power, and compact CMOS based potentiostat for vertically aligned carbon nanofibers (VACNF) based amperometric glucose sensors. The CMOS based potentiostat consists of a single-ended potential control unit, a low noise common gate difference-differential pair transimpedance amplifier and a low power VCO. The potentiostat current measuring unit can detect electrochemical current ranging from 500 nA to 7 [Formula: see text] from the VACNF working electrodes with high degree of linearity. This current corresponds to a range of glucose, which depends on the fiber forest density. The potentiostat consumes 71.7 [Formula: see text] of power from a 1.8 V supply and occupies 0.017 [Formula: see text] of chip area realized in a 0.18 [Formula: see text] standard CMOS process.

A novel stem cell culture model of recurrent glioblastoma.

Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults with average disease relapse at 9 months and median survival rarely extending beyond 15 months. Brain tumor stem cells (BTSCs) have been implicated in not only initiating GBM but also conferring resistance to therapy. However, it is not clear whether the BTSC population that initiates tumor growth is also responsible for GBM recurrence. In this study, we have developed a novel in vitro treatment model to profile the evolution of primary treatment-naïve GBM BTSCs through chemoradiotherapy. We report that our in vitro model enriched for a CD15+/CD133- BTSC population, mirroring the phenotype of BTSCs in recurrent GBM. We also show that in vitro treatment increased stem cell gene expression as well as self-renewal capacity of primary GBMs. In addition, the chemoradiotherapy-refractory gene signature obtained from gene expression profiling identified a hyper-aggressive subtype of glioma. The delivery of in vitro chemoradiotherapy to primary GBM BTSCs models several aspects of recurrent GBM biology, and could be used as a discovery and drug-screening platform to uncover new biological drivers and therapeutic targets in GBM.

Culture and Isolation of Brain Tumor Initiating Cells.

Brain tumors are typically composed of heterogeneous cells that exhibit distinct phenotypic characteristics and proliferative potentials. Only a relatively small fraction of cells in the tumor with stem cell properties, termed brain tumor initiating cells (BTICs), possess an ability to differentiate along multiple lineages, self-renew, and initiate tumors in vivo. This unit describes protocols for the culture and isolation BTICs. We applied culture conditions and assays originally used for normal neural stem cells (NSCs) in vitro to a variety of brain tumors. Using fluorescence-activated cell sorting for the neural precursor cell surface marker CD133/CD15, BTICs can be isolated and studied prospectively. Isolation of BTICs from GBM bulk tumor will enable examination of dissimilar morphologies, self-renewal capacities, tumorigenicity, and therapeutic sensitivities. As cancer is also considered a disease of unregulated self-renewal and differentiation, an understanding of BTICs is fundamental to understanding tumor growth. Ultimately, it will lead to novel drug discovery approaches that strategically target the functionally relevant BTIC population.

STAT3 pathway regulates lung-derived brain metastasis initiating cell capacity through miR-21 activation.

Brain metastases (BM) represent the most common tumor to affect the adult central nervous system. Despite the increasing incidence of BM, likely due to consistently improving treatment of primary cancers, BM remain severely understudied. In this study, we utilized patient-derived stem cell lines from lung-to-brain metastases to examine the regulatory role of STAT3 in brain metastasis initiating cells (BMICs). Annotation of our previously described BMIC regulatory genes with protein-protein interaction network mapping identified STAT3 as a novel protein interactor. STAT3 knockdown showed a reduction in BMIC self-renewal and migration, and decreased tumor size in vivo. Screening of BMIC lines with a library of STAT3 inhibitors identified one inhibitor to significantly reduce tumor formation. Meta-analysis identified the oncomir microRNA-21 (miR-21) as a target of STAT3 activity. Inhibition of miR-21 displayed similar reductions in BMIC self-renewal and migration as STAT3 knockdown. Knockdown of STAT3 also reduced expression of known downstream targets of miR-21. Our studies have thus identified STAT3 and miR-21 as cooperative regulators of stemness, migration and tumor initiation in lung-derived BM. Therefore, STAT3 represents a potential therapeutic target in the treatment of lung-to-brain metastases.