[HN Gopher] CDs to flexible biosensors: Researchers discover ine...
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       CDs to flexible biosensors: Researchers discover inexpensive
       recycling method
        
       Author : giuliomagnifico
       Score  : 46 points
       Date   : 2022-07-27 11:38 UTC (11 hours ago)
        
 (HTM) web link (www.binghamton.edu)
 (TXT) w3m dump (www.binghamton.edu)
        
       | mikewarot wrote:
       | Why not just buy gold leaf? It's about the same price, and you
       | know what you're getting.
        
       | rob74 wrote:
       | AFAIK only (some) CD-Rs had a gold reflective layer, factory-
       | pressed CDs use aluminum - so no gold, no silver. It's a bit
       | strange that they started the whole project apparently without
       | having a clue whether it would have actual practical value ("We
       | used gold CDs, and we want to explore silver-based CDs, which I
       | believe are more common.").
        
         | awiesenhofer wrote:
         | There are lots and lots of gold CDs out there. Sony, Verbatim,
         | Kodak, etc all sold these "premium"/"gold"/"archival grade"
         | versions. Even if its not billions like with aluminium, its
         | definitly millions and a vast ressource to recycle. Sounds like
         | a lot of practical value to me.
        
       | ggm wrote:
       | Most people (myself included) tend to think of a sensor as having
       | some specific active measurement component. So a biologically
       | available dissolved oxygen sensor (BOD) (for instance) has a semi
       | permeable membrane, and an electrode, and measures the change in
       | conductivity in the region due to dissolved oxygen changing the
       | ability to pass volts through purified water. (ok, this was the
       | 70s. I have no idea how they work now) The point is you pump
       | volts across a gap, the membrane changes how they flow. Voila!
       | dissolved oxygen changes the resistivity, you get to read how
       | much dissolved oxygen was in the sample.
       | 
       | But, the word is also applicable to a passive device if it can
       | pick up a signal which can then represent a modulation of some
       | other thing, through RF. The tip of a logic/IC probe, or a
       | portable volt-amp meter in this instance is what they are calling
       | the "sensor" when in fact, the sensor is the increadibly finely
       | balenced coil and spring and magnet: the probe is just how the
       | data comes in. (ok this is the 1890s. I have no idea how this
       | works now)
       | 
       | It's an antenna system. The Electrode gap, in my BOD example, but
       | sans volts. You have to add the volts. Either it injects and
       | reads, or its read-only. its the tip of the probe. Its got no
       | active elements. How it "reads" depends on how you can convert
       | something under measurement into a signal which it can pick up.
       | The actual "sensor" component might be somewhere else. This is
       | the transducer which you attach to something.
       | 
       | I am guessing it can be used to make RFID antenna as well. That
       | would be cool. Does anyone remember the sparkle gaps you got for
       | the back of AMPS cellphones which lit up like a christmas tree
       | when the 'wake up' signal was pumped into the phone?
       | 
       | Actually nowadays, a dissolved oxy meter is probably best known
       | as a fingerclip LED reader, and measures things by shining a red
       | LED at your flesh to pick up on some aspect of the blood flow in
       | a finger. I don't see any selectively permeable membrane there,
       | its using another effect to measure. Passive probe? well.. you do
       | shine an LED. so theres a transducer involved..
        
       | boplicity wrote:
       | Original paper:
       | 
       | https://www.nature.com/articles/s41467-022-31338-9
        
         | adolph wrote:
         | Thanks, this is fascinating!
         | 
         |  _Verbatim archival gold CDs and the PI tape were purchased
         | through Amazon for the UCDE fabrication illustrated in Fig. 1a
         | and patterned with a Cricut Maker(r) fabric cutter._
         | 
         |  _The ECG MCU was designed with a uBIC-MZ24C20R (MEZOO, Inc,
         | South Korea) chipset, which is a high-performance, low-powered
         | one-chip 1 channel ECG (lead I) biometric sensor module with a
         | 32-bit ARM Cortex-M0 processor. ECG data from two leads (RA and
         | LA) were collected with 24-bit ADC resolution and 1 kHz
         | sampling rate and then transmitted to a smartphone application
         | in real-time via Bluetooth low-energy (BLE) communication._
        
         | montecarl wrote:
         | Figure 2 shows that the CD material is used kind of like
         | electrodes or probes and those are attached to a
         | microcontroller. This makes much more sense to me than the
         | headline and main article.
        
       | encryptluks2 wrote:
       | Is that $1.50 per device from the conversion process or extra
       | materials? I remember getting stacks of 50 CDs for like $5.
        
       | mkmk wrote:
       | The pictures are pretty but surely a bunch of metallic squiggles
       | doesn't make a sensor....... right?
        
         | ugjka wrote:
         | > The flexible circuits then would be removed and stuck onto a
         | person. With the help of a smartphone app, medical
         | professionals or patients could get readings and track progress
         | over time.
         | 
         | 1) Draw a circle
         | 
         | 2) Draw the rest of the owl
         | 
         | /s
        
         | adg001 wrote:
         | Indeed the pictures are not representative of the real setup.
         | Anyway the idea is clever. The paper provides an overview about
         | most of the missing bits, such as the mcu, power source, and
         | software.
        
         | dathanb82 wrote:
         | One of the applications is as an alternative electrode for
         | ECG's. You'd attach a line from that sensor to an ECG machine
         | (sorry, not an expert, so apologies for the imprecise
         | terminology) and get similar results to using commercial
         | electrodes.
         | 
         | I dunno if that makes it a sensor, technically, or just one
         | component in a more complex sensor apparatus.
        
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       (page generated 2022-07-27 23:02 UTC)