Bio-integrated Systems Research Articles

Building wireless sensor networks with biological cultures: components and integration challenges

The development of wireless sensor networks (WSNs) struggles with limited computing, communication, and energy resources. Bio-Integrated Systems (BISs) contain cultured cells that perform certain tasks. For instance, neurons can work as brains for robots. BISs could provide solutions to overcome WSNs resource constraints. Biological entities integrating in computing hardware gains interest especially in robotics. This interest is due to the potentials of such integration in deep learning capacity, massive parallelism, energy savings, and communication and integration with living subjects. This paper collects existing BISs research and provides research motivations for Bio-Integrated WSNs (BI-WSNs). BI-WSNs solutions for improving energy preserving, sensing, processing, and communication are proposed and supported with existing examples. Further, on-going research on integrating neural networks in WSNs is presented. Challenges related to protection of biological entities from external environment are discussed. Finally, a prospective model of BI-WSNs consisting in optogenetic communication combined with neural network processing is given.

Survey and evaluation of neural computation models for bio-integrated systems

Integrating neurobiological cultures with computer systems presents an opportunity to enhance computational energy efficiency. These Bio-Integrated Systems (BISs) require knowledge about structure and behavior of neural components and their interfacing. In the early design phases, modeling neurons offers cost, failure-free and retrial benefits compared to laboratory grown neural networks. The usefulness of these models lays in characteristics of being realistic but also computationally efficient.This survey reviews computational models of spiking neurons and their changes in connections, known as plasticity. The review studies models that are faithful to real neural cultures, and are computational efficient for real-time BISs. Also, criteria and methods for comparing models with ‘in-vitro’ experiments are reviewed to conclude on the level of realism of models in comparison with biological setups. Izhikevich’s model of spiking neurons is recommended due to its accuracy in reproducing real neural firing patterns, computational efficiency, and ease of parameter adjustment. The model of Spike-timing dependent plasticity is recommended as current basis for representing neuron changes in connections. For the analysis of network connectivity and connectivity changes in BIS, the Cox method is recommended because it evaluates connections based on activities from all recorded neurons as opposed to pair-wise approaches.

Non-wrinkled, highly stretchable piezoelectric devices by electrohydrodynamic direct-writing

Piezoelectric structures, in forms that allow mere in-surface deformations under large strains, are attractive for bio-integrated systems. Here, mechano-electrospinning (MES) is presented to direct-write straight nanofibers of polyvinylidene fluoride onto a prestrained poly(dimethylsiloxane) (PDMS) substrate, to position and polarize a piezoelectric nanofiber array in one-step. Wrinkled/non-wrinkled buckling modes are found when the substrates are released, and the morphology of the direct-written fiber proved the key to determine the buckling modes, which can be tuned precisely by MES parameters. The non-wrinkled, stretchable piezoelectric devices with a highly synchronized serpentine fiber array exhibit their in-surface deformation and stable piezoelectric performance up the failure strain of PDMS (∼110% in our study), which may be used as stretchable sensors and energy converters/providers.

Sistemas de recirculación acuapónicos

El sistema de producción acuapónico es un sistema biointegrado que juntala acuicultura de recirculación y la producción hidropónica de plantas. Losnutrientes, que son excretados directamente por los organismos acuáticoso generados por las reacciones microbianas sobre los desechos orgánicos,son absorbidos por las plantas cultivadas hidropónicamente. El uso de sistemasacuapónicos tiene varias ventajas sobre los sistemas de recirculaciónen acuicultura y los sistemas hidropónicos que usan nutrientes inorgánicos.Una de ellas es el aprovechamiento de los desechos generados por los componentesacuáticos, los cuales constituyen un problema en todos los sistemasde producción. Al presentar Colombia un gran potencial de producción depeces y plantas, resulta indispensable y necesario fomentar la realizaciónde proyectos que vinculen los dos sistemas de producción. La siguienterevisión tiene como objetivo describir, de forma general, los sistemas derecirculación acuapónicos

Viabilidade econômica da utilização do biogás produzido em granja suínícola para geração de energia elétrica

A produção de biogás por meio de biodigestão anaeróbia representa um avanço para equacionar o problema dos dejetos produzidos pela suinocultura e disponibilidade de energia no meio rural. Este trabalho teve como objetivo estimar a viabilidade econômica de um sistema biointegrado para geração de eletricidade a partir do aproveitamento de dejetos de suínos. Os dados para este estudo foram coletados em uma agroindústria, onde são realizadas diversas atividades agrícolas; entretanto, a suinocultura foi selecionada para o processo de análise de biodigestão anaeróbia, pelo fato de gerar uma grande quantidade de dejetos, com dificuldade de disposição no meio ambiente, configurando um estudo de caso. O biodigestor analisado é um modelo tubular contínuo, com calha de água em alvenaria e com uma manta plástica como gasômetro, onde são depositados diariamente os dejetos de 2.300 suínos em fase de terminação. O investimento inicial para implantação foi estimado em R$ 51.537,17, e os custos anuais do sistema foram de R$ 5.708,20 com manutenção, R$ 4.390,40 com depreciação e R$ 1.366,77 com juros. Concluiu-se que o sistema de produção de biogás é viável do ponto de vista econômico, se o consumo de energia elétrica for de 35 kWh por dia, em média, onde o valor presente líquido (VLP) é de R$ 9.494,90, e a taxa interna de retorno (TIR) é de 9,34% ao ano.