Apropos K

Pesticides on the fruit bowl? Just touch it with your finger to find out – wearing special rubber gloves ...

Image: istock / CollinsChin

There are good reasons why people wear rubber gloves – when there will be contact with dirt or blood or when corrosive or toxic substances need to be handled. If experienced experts know what kind of a substance they are dealing with or what poison is involved, they are in a position to take suitable protective measures. However, if this information is not available, well, then even an expert is in a pretty difficult situation. 

Scientists from the American Society of Chemistry (ASC) are developing a rubber glove that does more than just protect the hand against unwelcome contacts. With their rubber glove, it is even possible to analyse what kind of a substance is involved that one is coming into contact with [1].

The chemists call their invention “Lab-on-a-glove“, a name that is based on analytical systems involving microchips (lab-on-a-chip technology). In the case of the latter, the substance that needs to be examined is applied to a specially structured printed circuit board; in the case of the lab-on-a-glove technology, one simply touches the unknown substance with one’s thumb. 

Like the lab-on-a-chip technology, the analytical glove has structures that enable it to obtain chemical substances and analyse them. The special feature is, however: the use of rubber gloves as the laboratory platform quite literally requires extremely flexible laboratory facilities. 

Laboratory facilities in this context mean the areas in which specimen liquid is obtained and analysed. For this purpose, the ACS scientists invented a stretchable ink that they applied to the thumb and index finger of the rubber glove using the 3D printing process. The purpose of the fingertip area of the thumb is to obtain the specimen of the suspicious substance. Three parallel wavy lines were in turn applied to the index finger by the 3D printing process using the special ink. The wavy lines end at the bottom of the finger in a ring that is put on the index finger and that is connected via cables to a unit that transmits the readings to a computer or smartphone via Bluetooth.

So how does one obtain information about the kind of substance that is involved on the tip of one’s thumb? We know from biochemistry that enzymes only respond specifically to certain substances. This reaction can be measured and displayed. Advantage is taken of this fact in the lab-on-a-glove technology by incorporating the enzymes that specifically react to the substance in question in each individual case in the ink that is applied to the index finger of the rubber glove. The enzymes operate here as what are known as biosensors. 

The first lab-on-a-glove model was developed to detect organophosphate compounds that are included as active substances in chemical warfare agents (sarin, VX, ...) or are used in agriculture as pesticides. One application area for these analytical rubber gloves could be consumer protection, i.e. to make sure that fruit and vegetables polluted with pesticides are not sold at retail outlets. The mere touch of a finger might be enough ... 

Guido Deussing

Reference

Open Access: Rupesh K. Mishra, Lee J. Hubble, Aida Martín, Rajan Kumar, Abbas Barfidokh, Jayoung Kim, Mustafa M. Musameh, Ilias L. Kyratzis, and Joseph Wang, Wearable Flexible and Stretchable Glove Biosensor for On-Site Detection of Organophosphorus Chemical Threats, ACS Sens., Article ASAP, DOI: 10.1021/acssensors.7b00051, Publication Date (Web): March 3, 2017