Possibilities for Engineered Insect Tissue as a Food Source

Due to significant environmental concerns associated with industrial livestock farming, it is vital to accelerate the development of sustainable food production methods. Cellular agriculture may offer a more efficient production paradigm by using cell culture, as opposed to whole animals, to generate foods like meats, eggs, and dairy products. However, the cost-effective scale-up of cellular agriculture systems requires addressing key constraints in core research areas: (1) cell sources, (2) growth media, (3) scaffolding biomaterials, and (4) bioreactor design. Here we summarize work in the area of insect cell cultures as a promising avenue to address some of these needs. We also review current applications of insect cell culture and tissue engineering, provide an overview of insect myogenesis and discuss various properties of insect cells that indicate suitability for use in food production systems. Compared to mammalian or avian cultures, invertebrate cell cultures require fewer resources and are more resilient to changes in environmental conditions, as they can thrive in a wide range of temperature, pH and osmolarity conditions. Alterations necessary for large-scale production are relatively simple to achieve with insect cells, including immortalization, serum-free media adaptation and suspension culture. Additional benefits include ease of transfection, nutrient density, and relevance to seafood organisms. To advance insect-based tissue engineering for food purposes, it is necessary to develop methods to regulate the differentiation of insect cells into relevant cell types, characterize cell interactions with biomaterials with an eye toward 3D culture, design supportive bioreactor systems and quantify nutritional profiles of cultured biomass

Isolation and Maintenance-Free Culture of Contractile Myotubes from Manduca sexta Embryos

Skeletal muscle tissue engineering has the potential to treat tissue loss and degenerative diseases. However, these systems are also applicable for a variety of devices where actuation is needed, such as microelectromechanical systems (MEMS) and robotics. Most current efforts to generate muscle bioactuators are focused on using mammalian cells, which require exacting conditions for survival and function. In contrast, invertebrate cells are more environmentally robust, metabolically adaptable and relatively autonomous. Our hypothesis is that the use of invertebrate muscle cells will obviate many of the limitations encountered when mammalian cells are used for bioactuation. We focus on the tobacco hornworm, Manduca sexta, due to its easy availability, large size and well-characterized muscle contractile properties. Using isolated embryonic cells, we have developed culture conditions to grow and characterize contractile M. sexta muscles. The insect hormone 20-hydroxyecdysone was used to induce differentiation in the system, resulting in cells that stained positive for myosin, contract spontaneously for the duration of the culture, and do not require media changes over periods of more than a month. These cells proliferate under normal conditions, but the application of juvenile hormone induced further proliferation and inhibited differentiation. Cellular metabolism under normal and low glucose conditions was compared for C2C12 mouse and M. sexta myoblast cells. While differentiated C2C12 cells consumed glucose and produced lactate over one week as expected, M. sexta muscle did not consume significant glucose, and lactate production exceeded mammalian muscle production on a per cell basis. Contractile properties were evaluated using index of movement analysis, which demonstrated the potential of these cells to perform mechanical work. The ability of cultured M. sexta muscle to continuously function at ambient conditions without medium replenishment, combined with the interesting metabolic properties, suggests that this cell source is a promising candidate for further investigation toward bioactuator applications

New Challenges in Biorobotics: Incorporating Soft Tissue into Control Systems

The development of truly biomimetic robots requires that soft materials be incorporated into the mechanical design and also used as an integral part of the motor control system. One approach to this challenge is to identify how soft animals control their movements and then apply the found principles in robotic applications. Here I show an example of how a combination of animal kinematics, neural patterning and constitutive modelling of tissues can be used to explore motor control in the caterpillar, Manduca sexta. Although still in the early stages, these findings are being used to design and fabricate a new type of robot that does not have a rigid skeleton and is structured entirely from soft or compliant materials. It is hoped that this new robotic platform will promote the development of actuators, sensors and electronics that are compatible with soft materials

Silk coating as a novel delivery system and reversible adhesive for stiffening and shaping flexible probes

The performance of any implantable electrode depends not only on its recording or stimulation capabilities but also on its position in relation to the target site. Electrode displacement during or after implantation represents a major issue as it might result in tissue damage or incorrect recording or stimulation location, complicating the interpretation of experimental data. Although thin-film electrode arrays have overcome some of the main limitations of more traditional, stiffer probes, their intrinsic flexibility and unilateral contacts represent a new challenge: they tend to bend during insertion and are difficult to implant simultaneously while maintaining a specific relative position. Here, we present a method that addresses all these issues using a coating of silk fibroin, a versatile protein derived from silkworm cocoons. The method is demonstrated by acquiring electromyographic (EMG) recordings in Manduca sexta, a soft-bodied animal that exemplifies the issues of electrode insertion and placement in delicate and deformable tissues

Energy for Biomimetic Robots: Challenges and Solutions

Animals and autonomous robots need to carry their own fuel (unlike plants, they do not generate usable energy from their surroundings). Animals typically exceed the normal endurance and range of all our current untethered robots. As an obvious example, humans have tremendous burst speed (less than 10 seconds to run 100 meters) and endurance (running a 26-mile marathon), and they can continue to do everyday activities without refueling (eating) for several days. The typical cost of transport for humans is about 0.2. In comparison, most robots operate for less than 1 hour on their carried fuel; the cost of transport is 15 or 20 times more than that for animals. An intriguing insight is that passive dynamic walkers can approach the human cost of transport (the Cornell Ranger can walk nonstop for 65 km), but this is a single optimized task (walking) with none of the versatility of an animal that can step over objects and operate on varied terrain. What it does illustrate is that structures (and by extension, material properties) can be exploited to ‘‘get the most’’ out of a given fuel source. Surely, this is what animals do on a continuous basis. What do we need to do to give our robots similar capabilities? In particular, what are the special demands, advantages, and limitations of fuel storage and usage in soft robots? To begin exploring some of these issues and to also stimulate a larger dialog in the robot community, the following discussion has been compiled from a series of questions posed to the participants