Modulation of neuronal activity in cortical organoids with bioelectronic delivery of ions and neurotransmitters

Precise modulation of brain activity is fundamental for the proper establishment and maturation of the cerebral cortex. To this end, cortical organoids are promising tools to study circuit formation and the underpinnings of neurodevelopmental disease. However, the ability to manipulate neuronal activity with high temporal resolution in brain organoids remains limited. To overcome this challenge, we introduce a bioelectronic approach to control cortical organoid activity with the selective delivery of ions and neurotransmitters. Using this approach, we sequentially increased and decreased neuronal activity in brain organoids with the bioelectronic delivery of potassium ions (K+) and γ-aminobutyric acid (GABA), respectively, while simultaneously monitoring network activity. This works highlights bioelectronic ion pumps as tools for high-resolution temporal control of brain organoid activity toward precise pharmacological studies that can improve our understanding of neuronal function.

Modulation of neuronal activity in cortical organoids with bioelectronic delivery of ions and neurotransmitters

Precise modulation of brain activity is fundamental for the proper establishment and maturation of the cerebral cortex. To this end, cortical organoids are promising tools to study circuit formation and the underpinnings of neurodevelopmental disease. However, the ability to manipulate neuronal activity with high temporal resolution in brain organoids remains limited. To overcome this challenge, we introduce a bioelectronic approach to control cortical organoid activity with the selective delivery of ions and neurotransmitters. Using this approach, we sequentially increased and decreased neuronal activity in brain organoids with the bioelectronic delivery of potassium ions (K+) and γ-aminobutyric acid (GABA), respectively, while simultaneously monitoring network activity. This works highlights bioelectronic ion pumps as tools for high-resolution temporal control of brain organoid activity toward precise pharmacological studies that can improve our understanding of neuronal function.

Open-loop lab-on-a-chip technology enables remote computer science training in Latinx life sciences students

Despite many interventions, science education remains highly inequitable throughout the world. Among all life sciences fields, Bioinformatics and Computational Biology suffer from the strongest underrepresentation of racial and gender minorities. Internet-enabled project-based learning (PBL) has the potential to reach underserved communities and increase the diversity of the scientific workforce. Here, we demonstrate the use of lab-on-a-chip (LoC) technologies to train Latinx life science undergraduate students in concepts of computer programming by taking advantage of open-loop cloud-integrated LoCs. We developed a context-aware curriculum to train students at over 8,000 km from the experimental site. We showed that this approach was sufficient to develop programming skills and increase the interest of students in continuing careers in Bioinformatics. Altogether, we conclude that LoC-based Internet-enabled PBL can become a powerful tool to train Latinx students and increase the diversity in STEM.

Rapid Determination of the 'Legal Highs' 4-MMC and 4-MEC by Spectroelectrochemistry: Simultaneous Cyclic Voltammetry and In Situ Surface-Enhanced Raman Spectroscopy

The synthetic cathinones mephedrone (4-MMC) and 4-methylethcathinone (4-MEC) are two designer drugs that represent the rise and fall effect of this drug category within the stimulants market and are still available in several countries around the world. As a result, the qualitative and quantitative determination of 'legal highs', and their mixtures, are of great interest. This work explores for the first time the spectroelectrochemical response of these substances by coupling cyclic voltammetry (CV) with Raman spectroscopy in a portable instrument. It was found that the stimulants exhibit a voltammetric response on a gold screen-printed electrode while the surface is simultaneously electro-activated to achieve a periodic surface-enhanced Raman spectroscopy (SERS) substrate with high reproducibility. The proposed method enables a rapid and reliable determination in which both substances can be selectively analyzed through the oxidation waves of the molecules and the characteristic bands of the electrochemical SERS (EC-SERS) spectra. The feasibility and applicability of the method were assessed in simulated seized drug samples and spiked synthetic urine. This time-resolved spectroelectrochemical technique provides a cost-effective and user-friendly tool for onsite screening of synthetic stimulants in matrices with low concentration analytes for forensic applications.

Electric-field control of single-molecule tautomerization

The combination of a graphene field-effect transistor and a gate-tunable scanning tunneling microscope enables independent control over the electric field. Using this method, we studied the electric field effect on the tautomerization reaction.

Structural and functional role of anions in electrochemical water oxidation probed by arsenate incorporation into cobalt-oxide materials

Arsenate ions are incorporated in amorphous cobalt oxide catalysts at the periphery of the lattice or substituting cobalt ions.

Hot Carrier Extraction from Multilayer Graphene

Hot carriers in semiconductor or metal nanostructures are relevant, for instance, to enhance the activity of oxide-supported metal catalysts or to achieve efficient photodetection using ultrathin semiconductor layers. Moreover, rapid collection of photoexcited hot carriers can improve the efficiency of solar cells, with a theoretical maximum of 85%. Because of the long lifetime of secondary excited electrons, graphene is an especially promising two-dimensional material to harness hot carriers for solar-to-electricity conversion. However, the photoresponse of thus far realized graphene photoelectric devices is mainly governed by thermal effects, which yield only a very small photovoltage. Here, we report a Gr-TiO_x-Ti heterostructure wherein the photovoltaic effect is predominant. By doping the graphene, the open circuit voltage reaches values up to 0.30 V, 2 orders of magnitude larger than for devices relying upon the thermoelectric effect. The photocurrent turned out to be limited by trap states in the few-nanometer-thick TiO_x layer. Our findings represent a first valuable step toward the integration of graphene into third-generation solar cells based upon hot carrier extraction.

Ovarian low-grade stromal sarcoma with thecomatous features: a critical reappraisal of the so-called "malignant thecoma"

A case of low-grade ovarian stromal sarcoma in a postmenopausal woman is described. Although pelvic recurrences of the tumor followed 5 and 7 years after the original surgery, the patient has remained well and without evidence of tumor 3 years since the last operation. Histopathologic, electronmicroscopic, and hormonal studies are described. There was evidence of estrogenic stimulation by the theca elements of the tumor in this patient. Cases previously reported in the world literature as malignant thecoma were analyzed, and most of them were considered inadequately documented; indeed most of them were probably either sarcomatoid granulosa cell tumors, stromal sarcomas, or fibrosarcomas. If a thecoma ever becomes malignant, the tumor cells dedifferentiate so that they cannot be recognized any longer as theca cells; instead, they proliferate as a stromal sarcoma or fibrosarcoma. It is proposed, therefore, that the term "malignant thecoma" not be used. On the other hand, very rare malignant ovarian stromal tumors do exist, consisting of undifferentiated stromal cells, fibroblasts, and theca cells, which can show evidence of hormonal activity.

Brenner tumor and mucinous cystadenoma of borderline malignancy in a patient with Turner's syndrome

A 64-year-old woman with a 45,X karyotype and Turner's syndrome and recent onset of right lower quadrant pain was found to have a mucinous cystadenoma with focal areas of borderline malignancy and a typical Brenner tumor in the right adnexa. Ovarian tumors in patients with a 45,X karyotype and Turner's syndrome are extremely rare. The present paper is the first report of concurrence of these 2 tumors in an affected individual. The simultaneous occurrence and intimate admixture of these tumors in a patient believed to be devoid of germ cells would seem to favor a common histogenesis from the germinal epithelium.

Observations on the surface area of the abnormal transformation zone associated with intraepithelial and early invasive squamous cell lesions of the cervix

The apparent area of the abnormal transformation zone (TZ) of the cervix was measured in a total of 104 patients by a simple method with the use of the 1 and 5 mm. diameter circle in the center of the field of the Leisegang colposcope and the field of the colposcope itself. The visible area (mean +/- S.E.M.) of the abnormal TZ for five patients with microinvasive or occult carcinoma of the cervix (180.8 mm.2 +/- 62.2) was significantly larger (p less than 0.01) than that of 64 patients with major intraepithelial lesions (62.5 sq. mm.2 +/- 7.3) and 35 patients with minor intraepithelial lesions (45.8 sq. mm.2 +/- 11.7). The visible area of the abnormal TZ measured over 40 mm.2 in each of the five patients with invasive lesions but in only 42 of 99 (42%) patients with intraepithelial lesions. The TZ extended into the endocervical canal and could not be fully visualized in four (80%) of the patients with invasive lesions, 24 (38%) of patients with major intraepithelial lesions, and 11 (31%) of patients with minor intraepithelial lesions. The implications of these findings are discussed.

Some observations on the value of endocervical curettage performed as an integral part of colposcopic examination of patients with abnormal cervical cytology

A total of 259 patients underwent endocervical curettage as an integral part of colposcopic examination of patients with abnormal cervical cytology. The transformation zone was entirely visualized in 140 patients (54.1 per cent), and, in 8.6 per cent of this group, the endocervical curettings were abnormal. On no occasion did the endocervical curettage harbor the worst lesion when compared to the histology of the ectocervical biopsy, cone biopsy, and hysterectomy specimens. In 117 patients (45.2 per cent), the transformation zone could not be visualized in its entirety, and in 57.3 per cent the endocervical curettings were abnormal. In one patient of this group invasive carcinoma was present in the endocervical curettage, and in another patient invasive carcinoma was present in both the ectocervical biopsy and the endocervical curettage. Thus, when the entire transformation zone is not visualized in its entirety or at all, endocervical curettage appears to be of value since a frank invasive carcinoma may be diagnosed and a cone biopsy avoided.

An immunofluorescent study of basement membranes in squamous cell carcinoma of the cervix, vagina, and vulva

Basement membranes of 33 samples of in situ or invasive squamous cell carcinomas of the cervix uteri, vagina, and vulva were studied by defined immunofluorescence technics. Pooled serum from patients with bullous pemphigoid, containing specific antibody to squamous epithelial basement membrane, was utilized. Essentially normal basement membranes were found in all cases of in situ carcinoma and in 18 cases of invasive carcinoma. Basement membranes appeared poorly formed in three specimens with invasion and were absent in the remaining three. These findings support the premise that penetration of the basement membrane is not a valid criterion for distinguishing in situ from invasive squamous cell carcinoma.