Nanotechnology is a fun concept to play with, especially in movies and books. Black Panther, Spider Man and Iron Man’s sleek and powerful battle suits are all made of nanotech, which not only allows their suits to self-assemble on demand, but also heal the person wearing the suit. Tony used the nanotech to suture and heal his stab wound in the abdomen after Thanos stabbed him in Endgame.
Unfortunately, the reality is not quite there yet - but that doesn’t make it any less exciting. Here are some current and future examples of nanotech in health sciences.
But first, what is Nanotechnology?
Nanotechnology is science, engineering and technology at the molecular or subatomic level. It involves developing materials or devices smaller than 100 nanometres (one nanometre is one-billionth of a metre). 
It's difficult to imagine just how small that is, but here are some examples to put it into perspective
How can it be used in health sciences?
Nanotechnology is currently being applied to a range of studies to fight cancer and to diagnose - and even treat - Alzheimer's. Because nanoparticles are so small, they can get into and target areas that previously couldn't be reached with drugs or other treatments.
Nanotech's applications in the human body could be endless.
However, many challenges still stand in its way, such as reliability (can we trust it?), cost (how can we make it affordable), large-scale production and shelf-life. 
Sunscreen: nanotechnology is already present in your sunscreens. Nanoparticles like titanium dioxide and zinc oxide exist in many modern sunscreen products, due to their high protection against UV radiation and their lightweight feeling on the skin.
Textiles/Clothing: Nanoparticles are increasingly used as coatings on clothing to make them waterproof, microbicidal (microbe-killing) or UV-blocking e.g. silica or silver.
Wound dressings: Antimicrobial nanoparticles in wound dressings contain silver nanoparticles, which continuously release a low level of silver ions to provide protection against bacteria.
Theranostic nanoparticles: enter the body and help diagnose the disease, report the location, identify the stage of the disease, and provide information about the treatment response. For example the 'SmartCap' (image below)
Drug delivery nanoparticles: deliver drugs, heat, light or other therapeutics to specific sites of a disease (such as a tumor cell). This reduces the side effects in other parts of the body.
Cell repair nano robots (nanobots): Tiny robots that can repair or replace DNA in sick cells e.g. Chromosome Replacement Therapy. They could also use lasers to remove infected cells to fight infection, cancer cells to fight cancer or dead cells to “clean up” the body.
Wearable nanotech: can sense an external stimulus like strain, pressure or temperature and relay the information to a monitoring device for monitoring health parameters. These wearable sensors can be placed on or embedded in clothes or accessories, or attached to parts of the body like the wrist, and can be monitored by the person and even by the medical staff wirelessly. 
Temporary tattoos or electronic stickers: could measure insulin levels for diabetics, monitor temperature and heart rate for patients and could even monitor the level of protection from the sunscreen on your skin. How?
Carson Bruns, a pioneer in nanotechnology tattoos, has developed a tattoo that responds to UV light. So, as long as your sunscreen is on, you cannot see the tattoo, but the moment your sunscreen wears off, the tattoo lights up.
There are many more potential applications - so stay tuned!