0:03 3D bioprinting also just known as
0:05 bioprinting is a relatively new
0:08 technology that in theory would allow
0:11 humans to fabricate nearly any tissue or
0:13 organ from
0:16 scratch the fundamental idea behind bio
0:19 printing is quite similar to that of
0:22 ordinary 3D printing in which a material
0:25 usually plastic is printed one layer at
0:28 a time instead of plastic however
0:30 bioprinters use bio
0:33 usually composed of cells suspended in a
0:36 special gel known as a hydrogel which
0:39 helps to protect nourish and hold the
0:43 cells together some bioinks use a single
0:46 type of cells While others contain
0:48 multiple types of cells or multiple
0:51 bioinks are used Side by Side each with
0:55 a different cell type there are three
0:58 categories of bioprinting that I will be
1:00 discussing in this video which
1:02 differentiate in the method by which
1:05 they turn the bio-ink into a specific
1:08 shape note that due to the fact that
1:10 this is an emerging technology the exact
1:13 name and classification of various
1:16 methods vary from source to Source the
1:19 concepts however are Universal I choose
1:22 to group the various bioprinting methods
1:24 into the following categories extrusion-based
1:26 extrusion-based
1:29 bioprinting droplet based bioprinting
1:30 and energy based
1:33 bioprinting extrusion-based bioprinting
1:36 is similar to what most people would
1:38 think of when they think of conventional
1:41 3D printers it involves forcing
1:43 continuous filaments of a material
1:46 through a nozzle in a controlled manner
1:48 to create a 3D
1:51 structure the material is bio-ink which
1:54 as I said before usually consists of
1:56 cells and a
1:58 hydrogel the filaments are forced
2:00 through a nozzle by either th pneumatic
2:02 pressure which is basically air pressure
2:05 or mechanically derived pressure which
2:08 comes from things like Pistons or screws
2:11 the bio-ink must be stabilized quickly
2:14 or else it will not retain its shape the
2:17 bio-ink can be St stabilized in a number
2:19 of ways largely depending on the
2:22 hydrogel that is being used as an
2:25 example during printing the bio-ink can
2:28 be stabilized by spraying a Mist with a
2:31 cross-linking agent dissolved in it by
2:34 the way crosslinking just means linking
2:37 one polymer chain to another and this is
2:39 done to stabilize
2:42 bio-ink in contrast droplet-based
2:45 bioprinting deposits discrete volumes or
2:48 droplets of bio-ink onto a surface
2:51 droplet-based bioprinting methods
2:54 include inkjet based bioprinting microv
2:56 valve based bioprinting and Laser
2:58 induced forward transfer
3:01 bioprinting as as with extrusion-based
3:03 bioprinting the bio- Inc must be quickly
3:06 stabilized in order for the structure to
3:09 retain its shape and the exact manner in
3:11 which this is accomplished depends on
3:14 the hydrogel being used inkjet based
3:17 bioprinting shares a lot in common with
3:20 traditional inkjet printing here's how
3:22 it works at a high level a pulse of
3:25 pressure is used to eject a droplet of
3:28 bio-ink the pulse of pressure can be
3:30 generated in one of two ways way using
3:33 thermal mechanisms or pzo electric
3:36 mechanisms in the thermal mechanism a
3:38 small surface of the bioink is heated
3:41 and vaporized to create a bubble which
3:44 occupies a larger space than the liquid
3:46 bio-ink did creating pressure forcing a
3:49 droplet of bio-ink out of the nozzle
3:51 once the bubble collapses a bit of
3:54 bioink is sucked from the reservoir
3:57 refilling the chamber and the process is
4:00 repeated in the Paso Electric mechanis M
4:03 an electric current is applied to a pazo
4:05 electric actuator causing the chamber to
4:07 deform slightly forcing a droplet of
4:11 bio-ink out of the nozzle by the way a
4:14 pazo electric actuator is a device that
4:16 responds to an electric current by
4:19 stretching and bending then when the
4:21 electric current to the pazo electric
4:23 actuator ceases the shape returns to
4:26 normal and a bit of bio- in is sucked
4:28 from the reservoir refilling the chamber
4:32 and the process is repeated next micro
4:35 valve based bioprinting involves small
4:37 valves that can be accurately opened and
4:40 closed with electromagnets to deposit
4:42 droplets of bioin which is under
4:44 pressure usually pneumatic pressure
4:47 meaning air pressure laser induced
4:50 forward transfer bioprinting uses lasers
4:53 to accurately position cells on a
4:55 substrate or the place where the tissue
4:58 will lie laser induced forward transfer
5:01 bioprinting can consists of a laser a
5:05 focus lens a ribbon and a substrate the
5:07 ribbon could contain a sheet of
5:09 transparent quartz glass with a very
5:12 thin gold coating and a coating of
5:15 bio-ink when the laser reaches the gold
5:17 it Heats it and greatly expands it
5:19 propelling a very small amount of bio-
5:22 in to the substrate which will have been
5:24 coated with hydrogel to dampen the
5:27 kinetic energy of the droplet of bioin
5:30 this laser is quite precise and hence
5:32 this method is also quite
5:35 precise finally in energy- based
5:38 bioprinting a focused energy source
5:41 often a laser is used to selectively
5:45 solidify or stabilize a bio- Inc this
5:47 method differs from extrusion-based
5:49 bioprinting and droplet based
5:52 bioprinting in that the bio Inc is
5:55 already in place perhaps the most
5:57 notable method of energy-based
6:01 bioprinting is stereol lithog graphy in
6:03 stereol lithography a laser is employed
6:06 to selectively harden a small amount of
6:09 bioin which contains a light sensitive
6:12 hydrogel this substance lies on a
6:14 platform that is then moved away from
6:17 the laser by a small amount if in doing
6:20 so the platform is immersed into bio-ink
6:23 then a Fresh coat of bio-ink will flow
6:25 on top of the now hardened layer of
6:28 bio-ink or if the platform has sidewalls
6:30 then a fresh layer of bio-ink can be
6:33 coded separately this process is
6:36 repeated eventually leaving you with a
6:39 solid 3D structure once the liquid
6:42 bioink is washed away each category of
6:46 bioprinting has its own pros and cons I
6:49 won't bore you with all the specifics
6:51 however as an example laser induced
6:55 forward transfer bio printing is precise
6:58 and has a high printing resolution
7:01 nevertheless it is expensive cumbersome
7:04 and timec consuming hence different
7:07 methods are used for different needs
7:10 interestingly there are approaches being
7:12 developed that combine different
7:15 bioprinting methods in order to maximize
7:18 efficiency maximizing efficiency is
7:20 crucial for bioprinting certain
7:24 structures like organs in general organs
7:26 must be printed quite quickly and yet
7:28 they have certain parts that contain
7:30 lots of details that consequently
7:32 require bioprinting with a high
7:35 resolution other parts don't need to be
7:38 printed with such precision and time can
7:41 be saved by not printing at such a high
7:44 resolution so by combining certain
7:47 methods that print slowly with a high
7:49 resolution with those that print quickly
7:52 with a lower resolution one can optimize
7:54 the bioprinting
7:57 process while these bioprinting methods
8:00 are based on 3D printing living things
8:04 develop and change over time hence
8:06 bioprinting can often be thought of as
8:09 4D bioprinting where the cells in the
8:13 printed tissue proliferate interact and
8:18 change in various ways over time in fact
8:20 certain chemicals are often added to the
8:23 bio-ink to influence the behavior and
8:27 development of cells also over time
8:30 hydrogel is meant to slow fully degrade
8:32 and be replaced by the native extracellular
8:33 extracellular
8:37 Matrix The extracellular Matrix is the
8:40 non-living material that cells secrete
8:42 which fills the spaces between cells
8:46 protects cells and holds cells together
8:49 sounds familiar that's because hydrogels
8:52 are meant to resemble the extracellular
8:54 Matrix now that you understand how the
8:57 various methods of bioprinting work I
8:59 would like to highlight some cool applic
9:03 applications perhaps most notable is the
9:05 ability to print entire fully functional
9:09 organs from scratch doing this poses
9:11 unique challenges due to the intricacy
9:14 of organs but even printing complex
9:16 organs will likely be viable in the near
9:19 future if this is the case the demand
9:23 for organs on organ transplant lists can
9:25 finally be equal to the supply of
9:29 healthy organs with bioprinting healthy
9:31 cells can be taken from a patient's
9:34 organ and be allowed to proliferate a
9:37 little bit if possible and can then be
9:40 used in the bio-ink by taking cells from
9:43 a patient rather than from some other
9:45 individual the probability of an organ
9:47 being rejected by the patient's immune
9:51 system is drastically reduced in this
9:54 way bioprinted organs can be superior to
9:57 foreign donor derived organs and if
9:59 creating custom organs from a patient
10:01 own cells is not a viable option for
10:04 some reason because of urgency in
10:06 implanting a new organ for instance
10:08 there is still the option of having
10:10 generic pre-made
10:14 organs also a special type of cells
10:17 called stem cells introduces some pretty
10:19 cool possibilities allowing for
10:22 personalized organs even if directly
10:25 acquiring the necessary cells is
10:28 impossible stem cells are basically
10:31 cells with the ability to change their
10:35 functionality based on their environment
10:38 all of the cells in a human's body with
10:41 specific functions actually originate
10:45 from certain types of stem cells so
10:47 instead of being forced to take certain
10:50 cells from a patient like healthy cells
10:53 from a failing organ which may be very
10:56 hard or even impossible to acquire cells
10:59 can be taken say from the patient skin
11:02 and in a lab they can be artificially
11:04 transformed into stem cells which can
11:07 then be induced into developing into the
11:09 different cell types that are needed to
11:13 bioprint a healthy new organ as
11:15 previously mentioned stem cells allow
11:18 for increased flexibility in
11:21 bioprinting however note that actually
11:24 working with stem cells is quite
11:26 challenging and even bioprinting simple
11:30 tissues with them at this time is very
11:33 difficult bioprinting tissues is simpler
11:36 than printing entire organs and is still
11:39 extremely Valu in a number of ways for
11:43 example bioprinting can be used to
11:46 create vegan meat or leather to do this
11:49 a small number of certain cells must be
11:53 collected from say a cow then by
11:56 carefully controlling the conditions in
11:59 which the cells are held these cells can
12:02 proliferate after this the cells can be
12:05 collected and bioprinted in a strategic
12:07 Manner and in a bit of time what remains
12:11 is meat or leather besides moral
12:13 considerations with investment and
12:16 development in this field cultivating
12:19 meat and leather in this way could be
12:21 much more efficient and have a much
12:23 smaller negative effect on the
12:26 environment in terms of things like
12:30 carbon emissions land use and freshwater
12:34 use also bioprinting could radically
12:37 change the process of developing and
12:41 testing new drugs today pharmaceutical
12:44 companies test the efficacy and safety
12:48 of a potential new drug on animals if a
12:50 drug proves to have the desired effect
12:54 on animals primarily mice without harsh
12:57 side effects then the drug is tested on
13:01 humans often often there is no desired
13:03 effect on humans rendering the money
13:07 invested in developing that drug a waste
13:11 in fact 90% of drugs that showed promise
13:14 in animals have no significant effects
13:18 on humans occasionally the drugs can
13:21 even harm the humans being tested this
13:25 testing process is extremely expensive and
13:26 and
13:29 inconvenient with bioprinting human
13:33 tissue or even organs can be bioprinted
13:35 that more accurately mimic The Human
13:38 Condition and thus are more suitable for
13:41 testing drugs an organ on a chip is a
13:44 simplified miniature version of an organ
13:47 that aims to mimic a real organ so that
13:51 it can be used to test a new drug
13:53 technically organs on chips are not
13:56 inherently related to bioprinting but
13:59 bioprinted tissue can be used used to
14:02 enhance such devices with better
14:05 positioning of cells and
14:07 reproducibility in the near future it
14:10 may be possible to have a nearly
14:12 perfectly accurate system for testing
14:15 drugs by linking organs on chips
14:18 together in a microfluidic circuit which
14:21 would be known as a human on a chip what
14:25 this means is that to test an oral drug
14:27 for example the drug could first be
14:30 introduced to a partially bioprinted gut
14:32 on a chip which would absorb the
14:34 compound and send it to a partially
14:38 bioprinted liver on a chip where it is
14:40 metabolized the metabolites are then
14:43 sent to other partially bioprinted
14:45 organs on chips including the kidney on
14:49 a chip heart on a chip lung on a chip
14:53 and bone on a chip throughout this
14:56 process the organs are tested for any
14:59 intended or unintended response to the
15:02 the drugs a similar pipeline could be
15:04 used to test the safety and
15:07 effectiveness of other forms of drugs
15:10 note that in this process organs on
15:13 chips need not have the full
15:16 functionality of particular organs
15:19 instead they only mimic the parts of the
15:22 organ that are valuable in testing the
15:25 effects of a new drug also instead of
15:28 introducing a disease to healthy animals
15:30 and then testing various drugs to treat
15:33 the animals a disease could be directly
15:36 introduced to a human on a chip reducing
15:40 the amount of unnecessary suffering in
15:43 summary using bioprinting to test new
15:46 drugs could be both more efficient and
15:50 more ethical in a similar way the safety
15:53 of new Cosmetics could be tested without
15:55 using animals but using bioprinted tissue
15:56 tissue
15:59 instead although it would come with
16:01 important challenges of its own
16:04 bioprinting plants is a potential future
16:07 application of bioprinting with the
16:09 possibility of creating new plant
16:11 varieties with desired traits for
16:15 agricultural use looking ahead if or
16:18 even when bioprinting fully functional
16:21 organs is common practice the following
16:23 questions naturally arise can
16:26 bioprinting be used to create organs
16:29 with abilities superior to the organ
16:32 that we are born with for example can we
16:35 bioprint eyes with supervision or
16:37 bioprint super efficient lungs as found
16:41 in Elite athletes is such a use of
16:44 bioprinting ethical will bioprinted
16:47 organs and super organs be reserved for
16:50 the rich these are important questions
16:52 that we must ask ourselves as this
16:55 technology is further developed thanks
