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Method 1

Protein Building Blocks

Protein building Blocks (without additional Streptavidin) . The single building blocks contain N- and C-terminal catcher-tag elements to form a permanent lock-key system. The polymer is build of two different building blocks as one single building block cannot be handled without instant polymerization. Mixing of the two building blocks start the polymerization via condensation reaction leading to a biopolymer tissue.

Pilis/Carbon Nano Tubes

Carbon Nanotubes (CNTs) are tubular architectures made of pure carbon. Every single carbon atom is sp2 hybridized and arranged in a hexagonal pattern. One can distinguish between Single Walled Carbon Nanotubes (SWCNTs) and Multi Walled Carbon Nanotubes (MWCNTs). The fabrication of the tubes can either be achieved by laser ablation of graphite or with a catalyst in a carbon rich gas phase. As pure carbon material, they are light-weight and flexible and robust. Further their thermal and electric conductivity is highly remarkable.

Artificial Muscle

Dielectric Elastomer Actuators (DEAs) are made of alternating layers of elastic and conductive material e.g. CNTs forming a stacked capacitor. The top and bottom contacts are metallic electrodes. By application of a voltage the elastomer between the cathodes and anodes is compressed in z-dimension and expands in the x,y-plane. This leads to a muscle-like contraction of the whole system.

Method 2

Protein Building Blocks

Protein building Blocks (with additional Streptavidin). The single building blocks contain N- and C-terminal catcher-tag elements with a streptavidin in the center of the protein. The catcher-tag system binds a permanent lock-key system to each other. The streptavidin unit can bind to the biotin functionalized azo dye to integrate the molecules into the polymer tissue.

Azo Dye
 

Molecular Machines (Azo dyes) can fulfill motion on a molecular length scale. The contraction of the dye is driven by light, which changes the conformation of the -N=N- bond from trans to cis. Implemented in high number in a tissue they can lead to contraction of the whole tissue. The invention of such small motors was awarded the nobel prize in chemistry in 2016.

Artificial Muscle

Muscle tissue with molecular machines can be obtained by combining biopolymeric tissue with an integrated streptavidin moiety. The streptavidin can bind a biotin functionalized azo dye leading to a further cross-linking. Via light-irradiation the azo dye molecules change their conformation and contract the tissue. Thermal or irradiation with a longer wavelength restores the position of the azo dye and the tissue relaxes to the original state.

The work, which is and can be done by robots is continuously increasing as well as the number of steps where complex shaped matter has to be handled. For this purpose, soft robotics are essential to prevent damage from the material. Current materials for soft robotics are based on silicones and related polymeric materials. Combined with electrically conductive materials in alternating layers, they form dielectric elastomer actuators (DEAs), which serve as muscle in robot arms. Silicones and elastic polymers can be counted to rather cost-efficient materials. However, considering the production of the material a high amount of electricity and chemical effort must be applied. This can be circumvented by a production from E. coli, where the organism produces a economically friendly biopolymer with the desired properties. The biosynthesis of the polymer building blocks, safes a significant amount of resources and energy.

The fabrication of the silicones to a device is carried out under elevated temperatures, where high accuracy at a micrometer scale is a crucial factor. This accuracy must also be maintained for the device made of biopolymer, which can be realized with modern 3D printers. Further, the 3D-printer is operating under ambient conditions, which safes money in the fabrication process. Due to the material properties, a special issue is the degradation of the biopolymer in dependence of time. A degradation of the material can mainly be circumvented by using the cell-free peptides, which prevents the consumption of the peptides by the cells. However, oxygen and mechanic stress are main issues, which have to be tackled. Oxygen can be excluded by instant packing of the material, whereas the mechanic durability of this material is still unknown. However, a comparison with a hydrogel polyacrylate based or a disposable DEA implies a lifetime of 100 to 2960 cycles.[1,2]

Biopolymer based DEA Silicone based DEA
Raw materials (price) 6 € /g ink [3,4] Av. 0,10 € /g ink[5]
Fabrication 3D printing 3D aerosol jet printing @ 80°C[6]
Solvent water Isopropanol/terpineol[6]
Weight est. 1 g/mL (density of water) 1.1-1.3 g/mL [7]
Waste Biodegradable polymer; Simple regain of conductive material Recycling of silicone possible, regain of conductive material complex to achieve
References [1] WALKER, Stephanie, et al. Using an environmentally benign and degradable elastomer in soft robotics. International Journal of Intelligent Robotics and Applications, 2017, S. 1-19. [2] https://arxiv.org/abs/1409.2611 [3] MACEWAN, Sarah R.; CHILKOTI, Ashutosh. Elastin‐like polypeptides: Biomedical applications of tunable biopolymers. Peptide Science, 2010, 94. Jg., Nr. 1, S. 60-77. [4] http://www.formedium.com/eu/products/escherichia-coli-media/media-for-optimal-cell-growth-and-yield-of-e-coli-cultures.html [5] MADSEN, Frederikke B., et al. The Current State of Silicone‐Based Dielectric Elastomer Transducers. Macromolecular rapid communications, 2016, 37. Jg., Nr. 5, S. 378-413. [6] REITELSHÖFER, Sebastian, et al. Aerosol-Jet-Printing silicone layers and electrodes for stacked dielectric elastomer actuators in one processing device. In: Electroactive Polymer Actuators and Devices (EAPAD) 2016. International Society for Optics and Photonics, 2016. S. 97981Y. [7] http://www.chemie.de/lexikon/Silikone.html

31
May

Synthesis trimethyl((4-nitrosophenyl)ethynyl)silane

Chemical equation:

Reagents:

M[g/mol] V[mL] m[mg] n[mmol]
Cul 190,45 - 0,057 0,3
Pd(PPh3)2Cl2 701,90 - 0,105 0,2
TMS 98,22 0,55 - -
TEA 101,19 0,55 - -
4-iodo-1-
nitrosobenzen
232,92 - 1,17 5,0
THF 72,11 10,0 - -

Procedure:

4-iodo-1-nitrosobenzen (1,17 g, 5,0 mmol), CuI (0,057 g, 0,3 mmol) and Pd(PPh3)2Cl2 (0,105 g, 0,2 mmol) in TMS (0,55 mL), TEA (0,55 mL) and THF (10,0 mL) were stirred at 55°C under nitrogen overnight. The reaction mixture was washed with brine, concentrated under reduced pressure and purified by silica gel column chromatography (hexanes/EtOAc, 35:1).

Yield:

Product trimethyl((4-nitrosophenyl)ethynyl)silane
M [g/mol] m[mg] n[mmol] Description of product
Fraction 2 203,32 0,090 0,44 Orange solid
Fraction 3 203,32 0,094 0,46 Yellow solid
Fraction 4 203,32 0,031 0,15 Brown solid

23
May

Synthesis 3,5-bis((4-((trimethylsilyl)ethynyl)phenyl)
diazenyl)benzoic acid

Chemical equation:

Reagents:

M [g/mol] V [mL] m [mg] n [mmol]
Cul 190,45 - 14,80 0,072
Pd(PPh3)2Cl2 701,90 - 25,59 0,036
TMS 98,22 0,2 - 1,44
TEA 101,19 0,2 - 1,44
3,5-bis((4- iodophenyl)diazenyl)-benzoic acid 328,19 - 251,51 1,2
THF 72,11 5,0 - -

Procedure:

3,5-bis((4-iodophenyl)diazenyl)-benzoic acid (251,51 mg, 1,2 mmol), CuI (14,80 mg, 0,072 mmol) and Pd(PPh3)2Cl2 (25,59 mg, 0,036 mmol) in TMS (0,2 mL), TEA (0,2 mL) and THF (5,0 mL) were stirred at 55°C under nitrogen overnight. The reaction mixture was concentrated under reduced pressure and purified by silica gel column chromatography (EtOH/DCM, 1:19).

Yield:

Product M [g/mol] m[mg] n[mmol]
3,5-bis((4-((trimethylsilyl)-
ethynyl)phenyl)diazenyl)-y
benzoic acid
522,76 0,218 0,4
Yield Practically: 33%
Description of product Orange solid

16
May

Synthesis 4-Iodo- 1-Nitrosobenzen

Chemical equation:

Reagents:

M [g/mol] ρ [g/cm3] V [mL] m [g] n [mmol]
4-iodo-1-nitrosobenzene 249,01 - - 4,05 16,3
Zn 65,38 - - 2,37 36,2
NH4Cl 53,49 - - 1,41 26,4
FeCl3 × 6 H2O 270,29 - - 13,00 48,1
2-methoxyethanol 76,09 0,97 130 - -
H2O/EtOH (5:1) 18,00/46,07 1,00/0,79 144 - -

Procedure:

4-Iodo-1-nitrobenzen (4,05 g; 16,3 mmol) was dissolved in 130 mL 2-methoxyethanol. Zn dust (2,37 g; 36,2 mmol) and NH4Cl (1,41 g; 26,4 mmol) was added and the reaction mixture was stirred at room temperature. The reaction was monitored by TLC (5:1 hexanes/EtOAc). After 30 minutes the solution was cooled to 0°C. FeCl3 × 6 H2O (13,00 g; 48,1 mmol) was solved in 144 mL H2O/EtOH (5:1) and added to the reaction mixture which then was stirred 3 hours at 0°C. Following the reaction mixture was extracted with EtOAc, washed with brine and dried over MgSO4. The yielded solution was concentrated under reduced pressure and purified by silica gel column chromatography (hexanes/EtOAc, 50:1). The solvent was removed and the product 4-iodo-1-nitrosobenzen (0,76 g; 3,3 mmol; 20%) was received as a green solid.

Yield:

Product M [g/mol] m[mg] n[mmol]
4-iodo-1-nitrosobenzen 233,0 0,76 3,3
Yield Literature: 82% Practically: 20%
Description of product Green solid

06
Apr

Synthesis 4-Iodo- 1-Nitrosobenzen

Chemical equation:

Reagents:

M [g/mol] ρ [g/cm3] V [mL] m [g] n [mmol]
4-iodo-1-nitrosobenzene 249,01 - - 3,991 16,03
Zn 65,38 - - 2,388 36,52
NH4Cl 53,49 - - 1,386 25,91
FeCl3 × 6 H2O 270,29 - - 13,108 48,49
2-methoxyethanol 76,09 0,97 120 - -
H2O/EtOH (5:1) 18,00/46,07 1,00/0,79 144 - -

Procedure:

4-Iodo-1-nitrobenzen (3,991 g; 16,03 mmol) was dissolved in 120 mL 2-methoxyethanol. Zn dust (2,388 g; 36,52 mmol) and NH4Cl (1,386 g; 25,91 mmol) was added and the reaction mixture was stirred at room temperature. The reaction was monitored by TLC (5:1 hexanes/EtOAc). After 30 minutes the solution was cooled to 0°C. FeCl3 × 6 H2O (13,108 g; 48,49 mmol) was solved in 144 mL H2O/EtOH (5:1) and added to the reaction mixture which then was stirred 3 hours at 0°C. Following the reaction mixture was extracted with EtOAc, washed with brine and dried over MgSO4. The yielded solution was concentrated under reduced pressure and purified by silica gel column chromatography (hexanes/EtOAc, 50:1). The solvent was removed and the product 4-iodo-1-nitrosobenzen (0,541 g; 2,3 mmol; 14%) was received as a green solid.

Yield:

Product M [g/mol] m[mg] n[mmol]
4-iodo-1-nitrosobenzen 233,0 0,541 2,3
Yield Literature: 82% Practically: 14%
Description of product Green solid

06
Apr

Synthesis 3,5-bis((4-iodophenyl)diazenyl)benzoic acid

Chemical equation:

Reagents:

M [g/mol] ρ [g/cm3] V [mL] m [g] n [mmol]
4-iodo-1-nitrosobenzene 233,00 - - 1,2 5,15
Acetic acid 152,20 - - 0,32 2,6
Acetic acid 60,05 1,05 30 - -

Procedure:

3,5-diaminobenzoic acid (0,32 g; 2,60 mmol) and 30 mL acetic acid was added to 4-iodo-1- nitrosobenzene (1,2 g; 5,15 mmol). The reaction mixture was stirred at room temperature overnight. The reaction mixture was concentrated under reduced pressure and purified via column chromatography (EtOH/DCM, 1:19).

Yield:

Product M [g/mol] m[mg] n[mmol]
3,5-bis((4-iodophenyl)
diazenyl)benzoic
acid
328,19 0,509 1,6
Description of product Orange/brown solid

05
Apr

Synthesis 4-Iodo- 1-Nitrosobenzen

Chemical equation:

Reagents:

M [g/mol] ρ [g/cm3] V [mL] m [g] n [mmol]
4-iodo-1-nitrosobenzene 249,01 - - 4,06 16,3
Zn 65,38 - - 2,53 35,7
NH4Cl 53,49 - - 1,43 26,7
FeCl3 × 6 H2O 270,29 - - 12,98 48,0
2-methoxyethanol 76,09 0,97 200 - -
H2O/EtOH (5:1) 18,00/46,07 1,00/0,79 144 - -

Procedure:

4-Iodo-1-nitrobenzene (4,06 g; 16,3 mmol) was dissolved in 200 mL 2-methoxyethanol. Zn dust (2,53 g; 35,7 mmol) and NH4Cl (1,43 g; 26,7 mmol) was added and the reaction mixture was stirred at room temperature. The reaction was monitored by TLC (5:1 hexanes/EtOAc). After 30 minutes the solution was cooled to 0°C. FeCl3 × 6 H2O (12,98 g; 48,0 mmol) was solved in 72 mL H2O/EtOH (5:1) and added to the reaction mixture which then was stirred 3 hours at 0°C. Following the reaction mixture was extracted with EtOAc, washed with brine and dried over MgSO4. The yielded solution was concentrated under reduced pressure and purified by silica gel column chromatography (hexanes/EtOAc, 50:1). The solvent was removed and the product 4-iodo-1-nitrosobenzene (1,2 g; 5,2 mmol; 32%) was received as a green solid.

Yield:

Product M [g/mol] m[mg] n[mmol]
4-iodo-1-nitrosobenzen 233,0 1,2 5,2
Yield Literature: 82% Practically: 32%
Description of product Green solid

16
Mar

Synthesis 3,5-bis((4-iodophenyl)diazenyl)benzoic acid

Chemical equation:

Reagents:

M [g/mol] ρ [g/cm3] V [mL] m [g] n [mmol]
4-iodo-1-nitrosobenzene 233,00 - - 0,863 3,7
Acetic acid 152,20 - - 0,299 2,0
Acetic acid 60,05 1,05 25 - -

Procedure:

3,5-diaminobenzoic (0,299 g; 2,0 mmol) acid in 25 mL acetic acid was added to 4-iodo-1- nitrosobenzene (0,863 g; 3,7 mmol). The reaction mixture was stirred at room temperature for four days. The reaction mixture was concentrated under reduced pressure and purified via column chromatography (EtOH/DCM, 1:19).
Fraction 3 was solved in 10 mL THF/water (1:1).
Fraction 4 was solved in 5 mL THF/water (1:1).

Yield:

Product M [g/mol] m[mg] n[mmol]
3,5-bis((4-iodophenyl)
diazenyl)benzoic
acid
Fraction 3 328,19 0,123 0,4
Fraction 4 328,19 0,026 0,08
Description of product Orange/brown solid

NMR

Azofarbstoff Fraktion 3 1. Synthese
NMR-Name: iGEM1

Azofarbstoff Fraktion(9)MeOH 1. Synthese
NMR-Name: iGEM2

14
Mar

Synthesis 4-Iodo- 1-Nitrosobenzen

Chemical equation:

Reagents:

M [g/mol] ρ [g/cm3] V [mL] m [g] n [mmol]
4-iodo-1-nitrosobenzene 249,01 - - 2,19 8,8
Zn 65,38 - - 1,46 22,3
NH4Cl 53,49 - - 0,71 13,3
FeCl3 × 6 H2O 270,29 - - 6,89 25,5
2-methoxyethanol 76,09 0,97 60 - -
H2O/EtOH (5:1) 18,00/46,07 1,00/0,79 72 - -

Procedure:

4-Iodo- 1-nitrobenzen (2,19 g; 8,8 mmol) was dissolved in 60 mL 2-methoxyethanol. Zn dust (1,46 g; 22,3 mmol) and NH 4 Cl (0,71 g; 13,3 mmol) was added and the reaction mixture was stirred at room temperature. The reaction was monitored by TLC (5:1 hexanes/EtOAc). After 50 minutes the solution was cooled to 0°C. FeCl 3 × 6 H 2 O (6,89 g; 25,5 mmol) was solved in 72 mL H 2 O/EtOH (5:1) and added to the reaction mixture which then was stirred 3 hours at 0°C. Following the reaction mixture was extracted with EtOAc (3 × 80 mL), washed with brine and dried over MgSO 4 . The received solution was concentrated under reduced pressure and purified by silica gel column chromatography (hexanes/EtOAc, 50:1). The solvent was removed and the product 4-iodo- 1-nitrosobenzen (0,6 g; 2,6 mmol; 30%) was received as a green solid.

Yield:

Product M [g/mol] m[mg] n[mmol]
4-iodo-1-nitrosobenzen 233,0 0,6 2,6
Yield Literature: 82% Practically: 30%
Description of product Green solid

14
Mar

Synthesis 3,5-bis((4-iodophenyl)diazenyl)benzoic acid

Chemical equation:

Reagents:

M [g/mol] ρ [g/cm3] V [mL] m [g] n [mmol]
4-iodo-1-nitrosobenzene 233,00 - - 0,60 2,6
Acetic acid 152,20 - - 0,18 1,2
Acetic acid 60,05 1,05 25 - -

Procedure:

3,5-diaminobenzoic (0,18 g; 1,2 mmol) acid in 25 mL acetic acid was added to 4-iodo- 1- nitrosobenzene (0,60 g; 2,6 mmol). The reaction mixture was stirred at room temperature for two nights. Following it was concentrated under reduced pressure.
¼ of the reaction mixture was purified via column chromatography (EtOH/DCM, 1:19).
¾ of the reaction mixture was washed with 5M NaOH and EtOAc. The aqueous phase was acidifies with AcOH to pH 2.
Observation: Green solid precipitates and the organic phase was orange. It was washed again with EtOAc and the combined extracts were concentrated under reduced pressure.

13
Mar

Synthesis 4-Iodo- 1-Nitrosobenzen

Chemical equation:

Reagents:

M [g/mol] ρ [g/cm3] V [mL] m [g] n [mmol]
4-iodo-1-nitrosobenzene 249,01 - - 2,04 8,2
Zn 65,38 - - 1,24 19,0
NH4Cl 53,49 - - 0,7 13,1
FeCl3 × 6 H2O 270,29 - - 6,58 24,3
2-methoxyethanol 76,09 0,97 60 - -
H2O/EtOH (5:1) 18,00/46,07 1,00/0,79 72 - -

Procedure:

4-Iodo- 1-nitrobenzen (2,04 g; 8,2 mmol) was dissolved in 60 mL 2-methoxyethanol. Zn dust (1,24 g; 19,0 mmol) and NH 4 Cl (0,7 g; 13,1 mmol) was added and the reaction mixture was stirred at room temperature. The reaction was monitored by TLC (5:1 hexanes/EtOAc). After 45 minutes the solution was cooled to 0°C. FeCl 3 × 6 H 2 O (6,58 g; 24,3 mmol) was solved in 72 mL H 2 O/EtOH (5:1) and added to the reaction mixture which then was stirred 3 hours at 0°C. Following the reaction mixture was extracted with EtOAc (3 × 80 mL), washed with brine and dried over MgSO 4 . The received solution was concentrated under reduced pressure and purified by silica gel column chromatography (hexanes/EtOAc, 50:1). The solvent was removed and the product 4-iodo- 1-nitrosobenzen (0,863 g; 3,7 mmol; 45%) was received as a green solid.

Yield:

Product M [g/mol] m[mg] n[mmol]
4-iodo-1-nitrosobenzen 233,0 0,863 3,7
Yield Literature: 82% Practically: 45%
Description of product Green solid

The term “molecular machine” refers to a system that is able to perform mechanical movement on a nanoscopic scale by application of an external stimulus. In order to do so, such systems only consist of a small number of molecules. Depending on the nature of the used molecules, possible stimuli can be electrical energy (redox changes), electromagnetic energy (light) or chemical energy (change of pH value or addition of specific ions). Being an exceptionally novel field of science, starting in the mid 1980’s and just being rewarded with the Nobel prize of chemistry in 2016, the current applications of molecular machines are still rather few. However, a multitude of possible applications are being explored by the minute. Many mechanical devices can be mimicked, including rotors, oscillators, gears, paddle wheels, turnstiles, brakes, ratchets and gyroscopes.[1] One example of a more sophisticated system is a molecular motor[2] that can perform a 360° rotation by subsequent application of light and temperature, as can be seen in Figure 1. In another research group, four similar rotary systems have been combined on a larger molecule in order to create a four-wheeled nano-car that was able to move over a surface upon irradiation.[3]

In this project, azo dyes are used as molecular machines. Upon irradiation, the -N=N- azo group changes from a trans configuration to a cis configuration. As a consequence, the distance between the substituents R is shortened, resulting in a muscle-like contraction. The working principle of azo dyes as molecular machines can be seen in Figure 2.


[1] V. Balzani, A. Credi, M. Venturi: Molecular Devices and Machines – A Journey into the Nano World, Wiley-VCH, Weinheim, 2003. [2] N. Koumura, R. W. J. Zijlstra, R. A. van Delden, N. Harada, B. L. Feringa, Nature, 1999, 401, 152-155. [3] T. Kudernac, N. Ruangsupapichat, M. Parschau, B. Maciá, N. Katsonis, S. R. Harutyunyan, K.-H. Ernst, B. L. Feringa, Nature, 2011, 479, 208-211.

DEAs, or dielectric elastomer actuators, generally consist of thin elastic films coated with compliant electrode material on two opposing phases. That makes them flexible plate capacitors that deform due to Maxwell stress when applying a voltage across the electrodes. Since the elastic material is incompressible, applying said voltage causes the reduction of the film in thickness to result in an expansion in area. Stacking and bundling of multiple DEAs allows an actuation system to be adapted to different loading scenarios.Several materials are suitable for manufacturing DEAs. Electrodes can be made e.g. of metals, polymers, graphite or carbon nano tubes. Elastic dielectric materials in use for industrial applications are Polyacryl, Polyurethane or Polysiloxane. This project however focusses on the synthesis of a catcher-tag polymer as dielectric medium while using carbon nano tubes for the electrodes.

Manufacturing DEAs is possible in multiple ways. Thereby dipping, spin-coating and casting techniques are widely spread. For biomaterials, cartridges are more suitable for handling and dispensing the dielectric material. For the application of electrodes onto the elastomer, sputter and spraying techniques are widely used within the industry. Another option is the selective wetting process based on water-based solutions for when the polymer material is hydrophobic.

Source: F. Nendel, S. Reitelshöfer: Conception of an infrastructure for the volumetric flow rate controlled supply of process gases and for the dynamic diversion of aerosol-flows for manufacturing flexible graphene electrodes. Institute for Factory Automation and Production Systems, (06/2017)

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