Recently, the safety of nanofibers has been brought into question again with another report suggesting potential harmful effect to lungs upon inhalation. Unfortunately, such headline grabbing news often misled the public who is unaware of the various types of nanofibers. For starters, experiments are often performed based on limited sample characteristics. The result is a fact for that tested sample characteristics and attributing the same outcome to samples beyond that specified characteristics are just hypothesis until sufficient evidences are gathered to generalize the effect. Over-generalization may mask other potential hazards or slow down research that brings significant benefit through the use of nanofibers. Since this blog is about electrospinning, the rest of the article will focus on nanofibers produced through this process.

For starters, nanofibers can be classified as organic or inorganic, long (centimeter and beyond) or short strand (less than a hundred micron) and diameter range (tens of nanometer or less or hundreds of nanometers). Most reports on the harmful effect of nanofibers are inorganic fibers that are relatively short and with diameters in the tens of nanometers or less. Such short strand fibers may be easily inhaled and cause inflammatory reaction in the lungs. On the other hand, electrospun nanofibers are generally polymers, length easily more than few centimeters and diameter typically in the hundreds of nanometers. With such length, the likelihood of electrospun nanofibers to reach the lung is highly improbable even without any protection. Electrospun nanofibers have been widely investigated for use as a tissue replacement scaffold and animal studies so far has been encouraging. Although having the nanofibers in the lungs may be different from direct implants, the effect needs to be tested before any conclusion be drawn. However, since the danger is about inflammation, we can hypothesize that the mechanism for inflammation of the lungs should show up if implanted as well.

There may be little hazard posed by exposure of electrospun nanofibers, nevertheless there are other hazards that lab users in particular needs to be aware of. High voltage is a danger but since current is very low, common precautions such as proper grounding of the charged tip before handling the equipment would be sufficient. The other danger which is commonly taken for granted is the exposure to the organic solvents used to prepare the spinning solution. While at the industrial level, there are legislations to reduce exposure of the workers to the solvent and the release of the solvent to the environment, there is little protection for those working the lab due to ignorance or lack of proper training. Commonly used lab gloves made of natural latex or nitrile is only good against specific solvents. Surgical face mask is no barrier to organic solvent vapors. When in doubt, check the material safety data sheet (MSDS or SDS) that comes with the chemical (See Electrospinning safety). Of course, a properly designed, commercially available electrospinning setup will provide the best engineering control against the hazards posed by electrospinning (See Industry).

At the lab scale, electrospinning is generally safe if proper precaution is taken. Despite the hype about potential dangers of nanofibers, a clear and present danger for electrospun nanofibers is the solvent and to a certain extent, the high voltage used. While it is still debatable whether electrospun nanofibers really pose a safety hazard, simple precaution like donning a facemask will reduce the likelihood inhaling nanofibers which may cause minor irritations.