The Power of Silk Technology for Energy Applications

Abstract

The energy demands that support modern industries and lifestyles are largely fulfilled by the burning of fossil fuels, [1] whose greenhouse gas by-products are a major contributing cause of global warming. [2] It has become clear that the combustion of fossil fuels at the current scale is unsustainable and more sustainable alternative energy sources must be explored to offset the contribution of fossil fuels. [3] Solar energy has an important role to play in this transition. Solar irradiation available on Earth's surface per hour far exceeds the annual global energy demand. [4] However, adaptation to solar energy has been slow due to a number of factors, such as rare or hazardous raw materials, high sensitivity to water, and short life spans. [5] Compared to the fossil fuel, which can be burned on demand, solar irradiation is subject to fluctuations caused by many factors such as weather conditions, time of the day, time of the year, and latitude. [6] Because storing solar radiation in its original form, that is, electromagnetic waves, is prohibitively difficult, its conversion prior to storage is necessary. Biological systems developed 3.5 billion years ago [7] as a process to use sunlight to drive chemical reactions through photosynthesis. Specifically, oxygenic photosynthesis, which occurs in most plants, algae, and cyanobacteria, converts carbon dioxide from the atmosphere into carbohydrates. These carbohydrates form dense and portable packets of chemical energy that can be released through cellular respiration whenever needed.The first step in following nature's example in turning light energy to chemical energy was enabled with the discovery of the photovoltaic effect by Edmond Becquerel in 1839, [8] in which the current generated by an electrochemical cell increased upon exposure to light. The first photovoltaic cells in the 19th century were based on pure metal species and exhibited low efficiencies. [9] Major efficiency improvements came in the 20th century with the incorporation of semiconductor materials into photovoltaic cells but they remained bulky and difficult to manufacture. [9] A breakthrough came in the 1980s with the advent of thin film solar cells which largely solved this problem. [9] Despite many advances, solar cells have a limited lifetime, and once their efficiencies have dropped to a no longer useful level, disposal becomes an issue due to the difficulty of recycling component materials. In addition, energy storage is often a major concern due to the limited number of hours per day photovoltaic devices are exposed to solar irradiation. Thus, Silk fibers are a remarkable material made of proteins possessing excellent mechanical properties that match or even outperform, in some aspects, high performance fibers such as Kevlar and steel. Silk proteins can be further produced recombinantly, allowing the possibility for genetic modification, enhancing silks' already impressive range of benefits. Thus far, little research has explored the possibility of incorporating silk-based materials in el...

Turning Food Protein Waste into Sustainable Technologies

“…The use of protein-based materials for renewable energy has already been reported and has relied so far on biohybrid materials as diverse as silk, 640 photoactive proteins, 641 light harvesting chlorophyll proteins, 642 pigment−proteins, 643 and other exotic energy-harvesting proteins. 644 However, the use of food proteins, and in particular food proteins from waste, for this task remains largely unexplored.…”

Bioengineering of spider silks for the production of biomedical materials

“…The versatility and multifunctionality of spider silk goes further than just mixing and matching the different properties of silk desired for a specific application, it can be placed as a key polymer in bridging the gap between sustainable materials and sustainable energy conversion for biomedical applications ( Strassburg et al, 2021 ).…”

Recent Research Progress of Ionic Liquid Dissolving Silks for Biomedicine and Tissue Engineering Applications

“…After degumming, SF can be prepared into different forms of materials, such as film [ 19 ], gel [ 20 ], microcapsule [ 21 ], 3D printed scaffold [ 22 ], fiber [ 23 , 24 ] and micro/nano particle [ 25 ] among others. These materials can be applied for drug delivery [ 21 , 26 ], wound healing [ 20 , 27 ], tissue engineering [ 28 , 29 ] and environment-related applications as well as in the energy sector [ 30 ]. However, the intrinsic properties of silk proteins depend on their source and processing methods applied [ 10 , 11 ].…”