In vitro electrochemical assessment of electrodes for neurostimulation in roach biobots.

Biobotics investigates the use of live insects as biological robots whose locomotion can be controlled by neurostimulation through implanted electrodes. Inactivity in the biobots (biological robots) can sometimes be noticed following extended neurostimulation, partly owing to incompatibility of implanted electrodes with the biobotic application or gradual degradation of the tissue-electrode interface. Implanted electrodes need to sufficiently exhibit consistent, reliable, and stable performance during stimulation experiments, have low tissue-electrode impedance, facilitate good charge injection capacity, and be compact in size or shape. Towards the goal of finding such electrodes suitable for biobotic applications, we compare electrochemical performances of five different types of electrodes in vitro with a saline based electrolytic medium. These include stainless steel wire electrodes, microfabricated flexible gold electrodes coated with PEDOT:PSS conductive polymer, eutectic gallium indium (EGaIn) in a tube, and "hybrid" stainless steel electrodes coated with EGaIn. We also performed accelerated aging of the electrodes to help estimate their longitudinal performance. Based on our experimentation, microfabricated electrodes with PEDOT:PSS and stainless steel electrodes coated with EGaIn performed remarkably well. This is the first time conductive polymer and liquid metal electrodes were studied comparatively for neurostimulation applications. These in vitro comparison results will be used in the future to provide a benchmark for subsequent in vivo tests with implanted electrodes in cockroach biobots.

Early metamorphic insertion technology for insect flight behavior monitoring.

Early Metamorphosis Insertion Technology (EMIT) is a novel methodology for integrating microfabricated neuromuscular recording and actuation platforms on insects during their metamorphic development. Here, the implants are fused within the structure and function of the neuromuscular system as a result of metamorphic tissue remaking. The implants emerge with the insect where the development of tissue around the electronics during pupal development results in a bioelectrically and biomechanically enhanced tissue interface. This relatively more reliable and stable interface would be beneficial for many researchers exploring the neural basis of the insect locomotion with alleviated traumatic effects caused during adult stage insertions. In this article, we implant our electrodes into the indirect flight muscles of Manduca sexta. Located in the dorsal-thorax, these main flight powering dorsoventral and dorsolongitudinal muscles actuate the wings and supply the mechanical power for up and down strokes. Relative contraction of these two muscle groups has been under investigation to explore how the yaw maneuver is neurophysiologically coordinated. To characterize the flight dynamics, insects are often tethered with wires and their flight is recorded with digital cameras. We also developed a novel way to tether Manduca sexta on a magnetically levitating frame where the insect is connected to a commercially available wireless neural amplifier. This set up can be used to limit the degree of freedom to yawing "only" while transmitting the related electromyography signals from dorsoventral and dorsolongitudinal muscle groups.

Electromagnetic levitation platform for wireless study of insect flight neurophysiology.

An electromagnetic levitation platform for use in a light emitting diode (LED) arena based virtual reality environment was developed for wireless recording of neural and neuromuscular signals from the flight related muscle groups in Manduca sexta. The platform incorporates the use of Early Metamorphosis Insertion Technology to implant recording electrodes into the flight muscles of late stage pupal moths. Analysis of the insects' response to changes in the LED arena rotation direction indicate that this setup could be used to perform a variety of flight behavior studies during yaw maneuvers.

Cocktails of human anti-cancer antibodies show a synergistic effect in nude mouse tumor xenografts.

A panel of four natural human monoclonal IgG antibodies derived from B lymphocytes isolated from regional draining lymph nodes of cancer patients has been developed and characterized. The four human antibodies are termed, RM1, RM2, RM3, and RM4. The immunoreactivity of this panel of four human antibodies is restricted to tumor cells. Individually, these human MAbs show tumor targeting and are effective in inhibiting tumor growth in nude mouse xenograft models. When used in combination the antibodies show an additive effect in slowing down the progression of tumors in xenograft models suggesting that cocktails of antibodies may be useful in the clinic.

Requirements for human antibody cocktails for oncology.

Cancer patients receiving antibodies as monotherapy have benefited from these treatments. However, significant improvements can be made that should make the therapy more effective. Applying lessons learned from the natural oligoclonal antibody response that cancer patients mount to their own tumours suggests that cocktails of monoclonal antibodies could be formulated, which may be more effective in treating cancers. The next phase of antibody immunotherapy will include cocktails of monoclonal antibodies. Various requirements for human antibody cocktails are discussed, as well as potential limitations of this approach.

Novel ganglioside antigen identified by B cells in human medullary breast carcinomas: the proof of principle concerning the tumor-infiltrating B lymphocytes.

The potential tumor-recognizing capacity of B cells infiltrating human breast carcinoma is an important aspect of breast cancer biology. As an experimental system, we used human medullary breast carcinoma because of its heavy B lymphocytic infiltration paralleled to a relatively better prognosis. Ig-rearranged V region V(H)-J(H), Vkappa-Jkappa, and Vlambda-Jlambda genes, amplified by RT-PCR of the infiltrating B cells, were cloned, sequenced, and subjected to a comparative DNA analysis. A combinatorial single-chain variable fragment Ab minilibrary was constructed out of randomly selected V(H) and Vkappa clones and tested for binding activity. Our data analysis revealed that some of the V(H)-J(H), Vkappa-Jkappa, and Vlambda-Jlambda region sequences were being assigned to clusters with oligoclonal predominance, while other characteristics of the Ab repertoire were defined also. A tumor-restricted binder clone could be selected out of the single-chain variable fragment kappa minilibrary tested against membrane fractions of primary breast tumor cells and tumor cell lines, the V(H) of which proved to be the overexpressed V(H)3-1 cluster. The specific binding was confirmed by FACS analysis with primary breast carcinoma cells and MDA-MB 231 cell line. ELISA and thin layer chromatography dot-blot experiments showed this target Ag to be a ganglioside D3 (GD3). Our results are a proof of principle about the capacity of B cells infiltrating breast carcinomas to reveal key cancer-related Ags, such as the GD3. GD3-specific Abs may influence tumor cell progression and could be used for further development of diagnostic and/or therapeutic purposes.