A Soft, Biocompatible Magnetic Field Enabled Wireless Surgical Lighting Patty for Neurosurgery
, Sungcheol Hong 1, Clinton Morgan 2, Peter Nakaji 2, Michael T. Lawton 2 and Sung Il Park 1,3,*Round 1
Reviewer 1 Report
In the submitted manuscript by W. S. Kim et al. with the title, “A Soft, Biocompatible Magnetic Field Enabled Wireless Surgical Lighting Patty for Neurosurgery,” authors developed a bio-electronics system fabrication and integration processes, which is designed for ‘wirelessly controllable lighting during neurosurgery’. Compared to conventional tools in neurosurgery such as lighting and neurosurgical patty, their proposed device can provide both functions in one device with improved light illumination function and wireless on/off operation. While the system itself in order to be used for neurosurgery as-is may have some limitations, it is clearly an interesting concept with advanced features and characteristics that can be useful for the suggested applications. In addition, authors provided a complete work with in-depth analysis of important aspects of the proposed system for the application. In the scope of this journal especially in the topic of “applied biosciences and bioengineering” with medical device and product related areas, the reviewer suggest that this work can be a strong contribution to Applied Sciences journal.
Despite good representation of the experimental results and good organization of the manuscript, the reviewer thinks that the manuscript will improve if some minor suggestions can be considered. Please see the following questions and suggestions.
Authors gave a good summary of battery or wireless power transfer strategies and analyzed limitations. It clearly justified the usage of wired connection of power supply. However, at the same time, the uniqueness of their system comes from wireless control by magnetic field. Along with the wired connection for power supply, it is then also possible to turn on/off the light using wired connection. Can authors explain still the wireless magnetic control can be beneficial with the option of wired connection? Assuming that the majority of the readers of this journal are not familiar with neurosurgery, it would be nice if authors can suggest functions of neurosurgical patty in the introduction. Authors gave some explanation, but it is not clearly noticeable when first reading the manuscript. This will clearly help the readers to understand the application and benefit of this work. The integration of existing simple, but effective electronic SMDs are great, but it could limit further functions such as full mechanical flexibility and required thinness. Can authors give some comments on the application of other advanced microelectronics technology for further development, such as flexible microelectronic devices for the same functionalities? Have authors also verified the functionality of the patty in terms of original function in neurosurgery, and whether the operation does not interfere with the functionality of the lighting operation? Or, any comment on expectation would be great. Lastly, on page 2, line 85-87, authors said that “The following table summarizes steps required for tests and fabrication of the surgical lighting patty and detail information on layout and components are found in Supplement.” However, in the supplementary files, only two video clips are available. Is there a chance that a word file missing? Please revise this section of manuscript if necessary.
Author Response
Comments: In the submitted manuscript by W. S. Kim et al. with the title, “A Soft, Biocompatible Magnetic Field Enabled Wireless Surgical Lighting Patty for Neurosurgery,” authors developed a bio-electronics system fabrication and integration processes, which is designed for ‘wirelessly controllable lighting during neurosurgery’. Compared to conventional tools in neurosurgery such as lighting and neurosurgical patty, their proposed device can provide both functions in one device with improved light illumination function and wireless on/off operation. While the system itself in order to be used for neurosurgery as-is may have some limitations, it is clearly an interesting concept with advanced features and characteristics that can be useful for the suggested applications. In addition, authors provided a complete work with in-depth analysis of important aspects of the proposed system for the application. In the scope of this journal especially in the topic of “applied biosciences and bioengineering” with medical device and product related areas, the reviewer suggest that this work can be a strong contribution to Applied Sciences journal.
Despite good representation of the experimental results and good organization of the manuscript, the reviewer thinks that the manuscript will improve if some minor suggestions can be considered. Please see the following questions and suggestions.
Point 1: Authors gave a good summary of battery or wireless power transfer strategies and analyzed limitations. It clearly justified the usage of wired connection of power supply. However, at the same time, the uniqueness of their system comes from wireless control by magnetic field. Along with the wired connection for power supply, it is then also possible to turn on/off the light using wired connection. Can authors explain still the wireless magnetic control can be beneficial with the option of wired connection?

Response 1: Point’s well taken. Wired configurations represent an alternative and they have been described in the patent that we filed. Surgical lighting patty can be activated/deactivated by an embedded reed switch(magnetic control). Main advantage of the approach is enhanced light intensity and long-term operation while retrieval stings should be long enough, at least 2 or 3 feet, for connections to a power supply due to safety issue.
Modifications to the manuscript: N/A
Point 2: Assuming that the majority of the readers of this journal are not familiar with neurosurgery, it would be nice if authors can suggest functions of neurosurgical patty in the introduction. Authors gave some explanation, but it is not clearly noticeable when first reading the manuscript. This will clearly help the readers to understand the application and benefit of this work.
Have authors also verified the functionality of the patty in terms of original function in neurosurgery, and whether the operation does not interfere with the functionality of the lighting operation? Or, any comment on expectation would be great.
Response 2: We agree that background on neurosurgical patties should be described.
Modifications to the manuscript: We added the following sentence at the beginning of 2nd paragraph in Introduction section; “Neurosurgical patties (referred to as cottonoids or neurosurgical sponges) are widely used in neurosurgery, and they can manage biofluids and protect neural tissues from damaged ones in surgical fields [Hermesniemi et al. 2005].”
Point 3: The integration of existing simple, but effective electronic SMDs are great, but it could limit further functions such as full mechanical flexibility and required thinness. Can authors give some comments on the application of other advanced microelectronics technology for further development, such as flexible microelectronic devices for the same functionalities?
Response 3: That could be an avenue for further research. In the meanwhile, we are looking into a path to mass production and our goal is to integrate all capabilities into a single platform at the lowest cost. This justifies the use of commercial components.
Modifications to the manuscript: N/A
Point 4: Lastly, on page 2, line 85-87, authors said that “The following table summarizes steps required for tests and fabrication of the surgical lighting patty and detail information on layout and components are found in Supplement.” However, in the supplementary files, only two video clips are available. Is there a chance that a word file missing? Please revise this section of manuscript if necessary.
Response 4: We fixed it and added to the manuscript.
Modifications to the manuscript: We revised the following sentence in 2.1 section and added a supplementary figure 1; “The following table summarizes steps required for tests and fabrication of the surgical lighting patty and detail information on layout and components are found in Supplementary Figure 1 and Video 1 & 2.”
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript, "A soft, biocompatible magnetic field enabled wireless surgical lighting patty for neurosurgery" by W.S. Kim et al., demonstrates an interesting new idea of using magnetism as a toggle switch of a surgical lighting patty. The idea is simple and effective. This translational research seems to have a set target in neurosurgery from the design of the work. I rate this work as highly meaningful. The manuscript is generally well written. I list a few minor points to further improve the quality of the manuscript.
(1) In section 2.1, "Biocompatible polymers, PDMS (50-100 um), ..." is an inadequate description to be in an academic paper. Unless the authors synthesized pure PDMS themselves and used it (in this case, details of polymer synthesis must be presented in the paper), the silicone material that the authors used is likely to be one of the off-the-shelf commercial product. Most of these products contain significant amount of silica and/or clay, so 'silicone' is a more appropriate term. In addition, some silicone are known to be biocompatible (FDA approved for specific uses), whereas biocompatibility of most other silicones are not established. All these being said, the authors must state the commercial name of silicone product, and provide adequate evidence that the silicone product is 'biocompatible'.
(2) Table 1: "Required time for 10 devices" ==> Why 10?
(3) Table 1, Progress level: Does this mean the step-wise required time per total required time? if so, it must be defined.
(4) Optical properties of the patty material must be described. Haze? transparency? refractive index ... The application is 'lighting', so optical properties of the patty material must be clearly stated.
Author Response
Comments: The manuscript, "A soft, biocompatible magnetic field enabled wireless surgical lighting patty for neurosurgery" by W.S. Kim et al., demonstrates an interesting new idea of using magnetism as a toggle switch of a surgical lighting patty. The idea is simple and effective. This translational research seems to have a set target in neurosurgery from the design of the work. I rate this work as highly meaningful. The manuscript is generally well written. I list a few minor points to further improve the quality of the manuscript.
Point 1: In section 2.1, "Biocompatible polymers, PDMS (50-100 um), ..." is an inadequate description to be in an academic paper. Unless the authors synthesized pure PDMS themselves and used it (in this case, details of polymer synthesis must be presented in the paper), the silicone material that the authors used is likely to be one of the off-the-shelf commercial product. Most of these products contain significant amount of silica and/or clay, so 'silicone' is a more appropriate term. In addition, some silicone are known to be biocompatible (FDA approved for specific uses), whereas biocompatibility of most other silicones are not established. All these being said, the authors must state the commercial name of silicone product, and provide adequate evidence that the silicone product is 'biocompatible'.

Response 1: We agree that detailed information on encapsulation should be provided.
Modifications to the manuscript: We revised the following sentence in section 2.1; “Biocompatible polymers, PDMS (SylgardTM 184 silicone elastomer kit, Dow®, thickness: 50-100 µm), encapsulate the central lighting layer by a simple coating process and are cured at a vacuum oven at 80 °C for 1 h.”
Point 2,3: Table 1: "Required time for 10 devices" ==> Why 10?
Table 1, Progress level: Does this mean the step-wise required time per total required time? if so, it must be defined.
Response 2,3: Quantity does not contain any scientific significance. We wanted to highlight these standard procedures are compatible with conventional semiconductor fabrication procedures.
Modifications to the manuscript: We added the following sentence in Table 1; “*Progress level (%) is based on the step-wise required time per total required time.”
Table 1. Step by step procedures for fabrication and test of the surgical lighting patty.
|
Process |
Purpose |
Required time for 10 devices |
Equipment/tools |
Progress level (%)* |
|
1. Preparation of Copper/Polyimide film on the glass |
Sampling for preparation of flexible circuits |
0.5 hour |
Scissors Kapton tape |
6% |
|
2. UV photo-lithography |
Define patterns including copper traces and contact pads |
2 hours |
Cleanroom Spin-coater Mask aligner |
30% |
|
3. Components transfer |
Mount electrical components on a substrate by soldering |
2 hours |
Microscope Ultrasonic cleaner Solder Enameled wire |
54% |
|
4. Functional testing |
Verify that devices functions as designed |
1 hour |
Magnets |
66% |
|
5. PDMS encapsulation |
Device packaging-1 |
1 hour |
Vacuum ovens |
78% |
|
6. Sponge encapsulation |
Device packaging-2 |
0.5 hour |
Patty Tweezers |
84% |
|
7. PDMS encapsulation |
Device packaging-3 |
1 hour |
Vacuum ovens |
100% |
*Progress level (%) is based on the step-wire required time per total required time.
Point 4: Optical properties of the patty material must be described. Haze? transparency? refractive index ... The application is 'lighting', so optical properties of the patty material must be clearly stated.
Response 4: Points are well taken and we agree that clear description should be provided. We made modifications to the manuscript.
Modifications to the manuscript: We revised the following sentences in 2.1 section, and modified relevant paragraph; “Next, we mount components including light emitting diodes which being used for light source (emitting color: white, material: InGaN, viewing angle: 140 º, and light intensity: 640 Lux (with sponge), 1420 Lux (without sponge); detail information in Figure 4(b)) of proposed patty, transistors, a reed switch, resistors, and capacitors on the patterns by soldering. ”
2.1. Fabrication for Surgical Lighting Patty
The process begins with a copper (Cu, thickness: 18 µm) / polyimide (PI, thickness: 12 µm) bilayer film (AC181200R, DuPont™ Pyralux® AC) on a glass slide (2” x 3”). Next, we deposit photoresist (AZ 1518, AZ®; spin-coating at 3000 r.p.m. for 30 sec; baking on a hot plate at 100 °C for 4 min) on top of a bilayer film. The UV photo-lithography enables to expose the light (UV intensity for 265 mJ/cm2) to form patterns on the prepared film with a patterned mask. Solvent development (AZ Developer 1:1, AZ®; for 30 sec) and wet etching (copper etchant, Alfa Aesar™; for 3 min) procedure define patterns including copper traces and contact pads on a flexible substrate. Next, we mount components including light emitting diodes (LED) which being used for light source (emitting color: white, material: InGaN, viewing angle: 140 °, and light intensity: 640 Lux (with sponge), 1420 Lux (without sponge); detail information in Figure 4(b)) of proposed patty, transistors, a reed switch, resistors, and capacitors on the patterns by soldering. Biocompatible polymers, PDMS (SylgardTM 184 silicone elastomer kit, Dow®, thickness: 50-100 µm), encapsulate the central lighting layer by a simple coating process and are cured at a vacuum oven at 80 °C for 1 h. Top and bottom surgical sponge then sandwiches together the encapsulated layer. This results in a thin (1 mm thickness), flexible surgical lighting patty. For powering the device, thin enameled wires twisted with retrieval strings connect batteries to the light-emitting element. Collectively, our de vices can be fabricated with 8 hours of effort in standard laboratory facilities using low cost commercially available components. The following table summarizes steps required for tests and fabrication of the surgical lighting patty and detail information on layout and components are found in Supplementary Figure 1 and Video 1 & 2.
Author Response File: Author Response.pdf
