Engler and Prantl system of classification in plant taxonomy
3D bioprinting
1. Bioprinting Instructions
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3D Bioprinting
XA.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456.
A.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456
Accurate control of cell distribution
High-resolution cell deposition
High-resolution cell deposition
1) Design the priting geometry
2) Selection of appropriate cell types
and hydrogels and bioink load
3) Bioink deposition under the control of
a computer
2. Bioprinting Techniques
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3D Bioprinting
XA.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456.
A.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456
InkJet Extrusion Laser-Assisted
3. Inkjet Bioprinting ‘’Drop-on-Drop’’
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3D Bioprinting
XA.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456.
A.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456
Hydrogel with encapsulated cells form the bioink ;
Thermal or acoustic forces to eject drops;
System drop-to drop
The material needs to be in the liquid state to form
drops and after form a solid 3D organized structure
Crosslinking strategies
Regeneration of lesions in situ
Controlled volumes of liquid delivered
High resolution, precision and speed
High cell viability (80%-90%)
Droplet size and deposition rate are controlled
electronically
• Microelectromechanical system causes:
• Mechanical stress
• Non uniform droplet size
• Frequent clogging of the nozzle
• Cannot be used with:
• High viscosity materials
• High cell density
• Cells settle and clog the bioprinter head
Advantages
Disadvantages
4. Extrusion Bioprinting
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3D Bioprinting
XA.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456.
A.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456
Wide variety of materials printed
Deposition of very high cell densities
High resolution, speed and spatial control
Allows deposition of spheroids multicellular
complex : self-assembling strategy
• Exposure to large mechanical stress that can
reduce cell viability
• Pneumatic nozzles can not precisely control
the deposited mass
• Cell survival rates in the range of 40-86 %
Advantages
Disadvantages
Movement along x,y,z axes
To dispense bioink it is used air-force pump or a
mechanical screw plunger
Prints uninterrupted cylindrical lines
Can print aggregates with high cell density and
diverse viscosities
Generation of tissues and organs
5. Laser-Assisted Bioprinting
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3D Bioprinting
XA.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456.
A.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456
No contact of the dispenser with the bioink
‘’Nozzle-free’’ avoids the clogging problem
Does not cause mechanical stress to the cells
Prints diverse materials and highly viscous
High cell viability (>95%)
• Cellular exposure to laser
• High-cost method
• Does not comprises droplet size and quality
• Does not accurately target cell position
deposition
• Metallic residues are formed owing to the
vaporization of the metallic laser-absorbing
layer
Advantages
Disadvantages
Donor layer containing an energy-absorbing layer
on the top and a layer of bioink solution
suspended on the bottom.
The laser pulse creates a high-pressure bubble at
the interface of the donor layer propelling the
suspended bioink.
6. Case study: Cell Viability
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3D Bioprinting
XA.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456.
A.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456
Cell viability can be controlled by varying the
parameters like pressure and nozzle diameter
Aim Understand cell state: whether If they were
live, injured or necrotic
Different nozzle diameter : 150,250 and 400 µ
Dispensed pressures: 5, 10, 20 and 40 psi
Percentage of live cells Percentage of injured cells Percentage of dead cells
It can be seen that the effect of pressure is significantly
larger than the effect of the nozzle diameter.
7. Case study: Generation of Cell Cocultures through ATS an ADE
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3D Bioprinting
XA.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456.
A.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456
Patterning cocultures of cells are
indispensable to understand the
interaction between multiple cells
Techniques to dispense cells fail
on dispense high-viability cell;
through long-time and large areas
Aqueous two-phase system
Acoustic droplet ejection
I. Contact-free
II. Nozzle-less
Aqueous two-phase system
8. Case study: Generation of Cell Cocultures through ATS an ADE
2211
3D Bioprinting
XA.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456.
A.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456
Patterning cocultures of cells are
indispensable to understand the
interaction between multiple cells
Techniques to dispense cells fail
on dispense high-viability cell;
through long-time and large areas
Aqueous two-phase system
Acoustic droplet ejection
I. Contact-free
II. Nozzle-less
Source
plate
Fixed distance between the transducer and the source plate
First, multiple wells were punched in the PDMS slab of the source
plate to house each different cell type
9. Case study: Generation of Cell Cocultures through ATS an ADE
2211
3D Bioprinting
XA.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456.
A.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456
The maximum height of travel for
an ejected droplet increased
linearly with increasing acoustic
pressure amplitude and pulse
duration of the applied ultrasound
Droplet volume increased linearly
with increasing acoustic pressure
and pulse duration, following a
similar trend to what was
observed for ejection height
Two simple pattern types, circle
arrays and lines, were created to
demonstrate the principal of spatial
patterning.
10. Case study: Skin replacement therapy
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3D Bioprinting
XA.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456.
A.B.C. Fulano, et al. (ANO), Journal com Nome Abreviado, 94(12): 123-456
It was used a free-form fabrication 3D printing to engineer a human plasma-derived bilayer skin using human
fibroblasts(hFBs) and keratinocytes (hKCs)
Bioprinter-Extrusion Method: a)Human Plasma b)CaCl2 ; c)hFBS; d)hKCs; C : heated bed; D:program system
11. The first 3 syringes were extruded into a P100 tissue plate and
incubated for 30 minutes for polymerization
hKCs were printed–> incubation during night
Printed skin equivalents were transplanted on to the backs of
mice
Also, skin equivalents were printed on transwell inserts and
hKCs were differentiated at the air-liquid surface
Case study: Skin replacement therapy
3D Bioprinting
In vivo: The substitute skin was placed on the
wounds and covered by skin previously
removed (8 weeks).
In vitro: differentiation at the air-liquid
interface for 17 days at 37 ºC.
12. Case study: Skin replacement therapy
3D Bioprinting
InvitruInvivo
Printed equivalents have
a similar structure to
normal human skin;
Also expression of keratin
K10;
Similar structure with
normal strata characteristics;
Green stain: Keratin K5
Green junction: collagen VII
Red stain: Keratin K10
Arrows: capillary
(dermal and epidermal
markers)
Immunofluoresce using skin
markers
Normal Human skin
13. Case study: Skin replacement therapy
3D Bioprinting
Surpassing known methods
that require high number of
cellular and acellular layers
to form dermis and
epidermis.
This bioprinting method
and bioinks allows the
production of human
bilayer skin, using human
plasma and hFBs and hKCs
3D bioprinting is a suitable
technology to generate
bioengineered skin for
therapeutical and
industrial applications
Conclusions
Editor's Notes
Thermal inkjet printers function by electrically heating the print head to produce pulses of pressure that force droplets from the nozzle. Several studies have demonstrated that this localized heating, which can range from 200 °C to 300 °C, does not have a substantial impact either on the stability of biological molecules, such as DNA52,53, or on the viability or post-printing function of mammalian cells. It has been demonstrated that the short duration of the heating (~2 μs) results in an overall temperature rise of only 4–10 °C in the printer head55. The advantages of thermal inkjet printers include high print speed, low cost and wide availability. However, the risk of exposing cells and materials to thermal and mechanical stress, low droplet directionality, nonuniform droplet size, frequent clogging of the nozzle and unreliable cell encapsulation pose considerable disadvantages for the use of these printers in 3D bioprinting.
Many inkjet printers contain a piezoelectric crystal that creates an acoustic wave inside the print head to break the liquid into droplets at regular intervals. Applying a voltage to a piezoelectric material induces a rapid change in shape, which in turn generates the pressure needed to eject droplets from the nozzle56. Other
However, because current printer heads are based on microelectromechanical
system (MEMS) devices, there is a relatively small
deformation generated by either thermal or piezoelectric actuation at
the nozzle opening. As a result, MEMS-based printer heads cannot
squeeze out high viscosity materials (N15 mPa/s) and do not work
well with bioinks with high cell density
Our group64 and others65 have shown that this limitation could be addressed by using materials that can be crosslinked after deposition by printing using chemical, pH or ultraviolet mechanisms. However, the requirement for crosslinking often slows the bioprinting process and involves chemical modification of naturally occurring ECM materials, which changes both their chemical and material properties. Additionally, some crosslinking mechanisms require products or conditions that are toxic to cells, which results in decreased viability and functionality66. Another limitation encountered by users of inkjet-based bioprinting technology is the difficulty in achieving biologically relevant cell densities. Often, low cell concentrations (fewer than 10 million cells/ml)42 are used to facilitate droplet formation, avoid nozzle clogging and reduce shear stress60. Higher cell concentrations
The inkjet approach facilitated the deposition of either primary cells or stem cell types with uniform density throughout the volume of the lesion, and maintained high cell viability and function after printing. These studies demonstrate the potential of inkjet-based bioprinting to regenerate functional structures
cell survival rates are in the range of 40–86%, with the rate decreasing with increasing extrusion pressure and increasing nozzle gauge76,80. The decreased viability of cells deposited by microextrusion is likely to result from the shear stresses inflicted on cells in viscous fluids. Dispensing pressure may have a more substantial effect on cell viability than the nozzle diameter90. Although cell viability can be maintained using low pressures and large nozzle sizes, the drawback may be a major loss of resolution and print speed. Maintaining high viability is essential for achieving tissue functionality.
Additionally, improvements in nozzle, syringe or motor-control systems might reduce print times as well as allow deposition of multiple diverse materials simultaneously82
Additionally, improvements in nozzle, syringe or motor-control systems might reduce print times as well as allow deposition of multiple diverse materials simultaneously82.
Microextrusion bioprinters have been used to fabricate multiple tissue types, including aortic valves93, branched vascular trees94 and in vitro pharmokinetic95 as well as tumor models96
Depending on the viscoelastic properties of the building blocks, the apposed cell aggregates fuse with each other, forming a cohesive macroscopic construct. One advantage of the self-assembling spheroid strategy is potentially accelerated tissue organization and the ability to direct the formation of complex structures.
Micropatterning strategies fall broadly into two categories:
(i) those that rely on substrate features, such as biochemical
or topographic patterns to position cells,11–13 and (ii) those
that actively dispense cells.14,1
To generate a scratch-free cell migration assay, we utilize an aqueous two-phase system (ATPS) consisting of polyethy lene glycol (PEG) and dextran (DEX) as the phase-forming polymers. [18] In this method, a submicroliter droplet of the DEX phase is spotted and dried on the fl oor of standard microwells. When the PEG phase containing suspended cells is added to these wells, the dried DEX spot rehydrates to form an immiscible droplet. The PEG-DEX biphasic system interfacial tension excludes cells from adhering to the part of the substrate covered by the rehydrating drop. This generates a well-defi ned circular cell-excluded area within a cell monolayer without the need for any special equipment or procedures other than standard pipetting equipment accessible at high throughput screening facilities. After washing away the ATPS medium, the rate and degree to which cells fi ll up the available space provides a measure of cell migration in a manner similar to wound healing assays.
Pulsed ultrasound exposures were used to generate dextran
droplets that were collected on the destination plate
HIFU: high intensity focused ultrasound
Micropatterning strategies fall broadly into two categories:
(i) those that rely on substrate features, such as biochemical
or topographic patterns to position cells,11–13 and (ii) those
that actively dispense cells.14,1
To generate a scratch-free cell migration assay, we utilize an aqueous two-phase system (ATPS) consisting of polyethy lene glycol (PEG) and dextran (DEX) as the phase-forming polymers. [18] In this method, a submicroliter droplet of the DEX phase is spotted and dried on the fl oor of standard microwells. When the PEG phase containing suspended cells is added to these wells, the dried DEX spot rehydrates to form an immiscible droplet. The PEG-DEX biphasic system interfacial tension excludes cells from adhering to the part of the substrate covered by the rehydrating drop. This generates a well-defi ned circular cell-excluded area within a cell monolayer without the need for any special equipment or procedures other than standard pipetting equipment accessible at high throughput screening facilities. After washing away the ATPS medium, the rate and degree to which cells fi ll up the available space provides a measure of cell migration in a manner similar to wound healing assays.
Pulsed ultrasound exposures were used to generate dextran
droplets that were collected on the destination plate
HIFU: high intensity focused ultrasound
Micropatterning strategies fall broadly into two categories:
(i) those that rely on substrate features, such as biochemical
or topographic patterns to position cells,11–13 and (ii) those
that actively dispense cells.14,1
To generate a scratch-free cell migration assay, we utilize an aqueous two-phase system (ATPS) consisting of polyethy lene glycol (PEG) and dextran (DEX) as the phase-forming polymers. [18] In this method, a submicroliter droplet of the DEX phase is spotted and dried on the fl oor of standard microwells. When the PEG phase containing suspended cells is added to these wells, the dried DEX spot rehydrates to form an immiscible droplet. The PEG-DEX biphasic system interfacial tension excludes cells from adhering to the part of the substrate covered by the rehydrating drop. This generates a well-defi ned circular cell-excluded area within a cell monolayer without the need for any special equipment or procedures other than standard pipetting equipment accessible at high throughput screening facilities. After washing away the ATPS medium, the rate and degree to which cells fi ll up the available space provides a measure of cell migration in a manner similar to wound healing assays.
Pulsed ultrasound exposures were used to generate dextran
droplets that were collected on the destination plate
HIFU: high intensity focused ultrasound
The function of CaCl2
is to induce the coagulation of the plasma fibrinogen
into a fibrin hydrogel.
Transwell permeable supports are backed by extensive citations, protocols, and scientific support—all to help create a cell culture that more closely mimics an in vivo environment
The printing process was
designed to produce a fibroblast-containing fibrin
hydrogel covered with a monolayer of hKCs
fibrin-based dermal matrix previously
developed by our group for the production of large
skin surfaces, useful in the treatment of severe and
extensive burns, wounds with loss of substance and
skin fragility diseases
In vivo
and in vitro assays were performed to analyse the
viability of these constructs and their capacity to
generate a terminally differentiated skin.
In vivo
and in vitro assays were performed to analyse the
viability of these constructs and their capacity to
generate a terminally differentiated skin.
The correct formation of the dermoepidermal
junction of the skin was confirmed by labelling
with an antibody against human collagen VII
(figure 4(B) green staining), the protein forming the
anchoring fibrils that bind together epidermis and
dermis.
From the immunohistochemical
point of view, K14 is a well-established marker of
epidermal basal cells as shown
*Este metodo é mais fácil em vez de imprimir um grande numero cellular e acellular em camadas, o que temos é depossição simultaneal de fibroblastos, plasma humano e cacl2 e por fim uma mono layer de hKCs
staining with dermal and epidermal
markers)
The results
showed that the generated skin had correct architecture
Secondly, the structure and functionality of the
printed human skin was further analysed on skinhumanized
Mice
and several differentiation markers such
as keratin 5 (a marker of proliferative basal keratinocytes),
human vimentin (a marker of hFBs), humancollagen
type VII (a marker of dermoepidermal basal
membrane), keratin 10 (a marker of suprabasal differentiated
keratinocytes) and human-filaggrin (a marker
of keratinocyte terminal differentiation)
Sobre os capilares This finding represents additional evidence of the
functionality of our skin regenerated from human bioprinted
equivalents.
In vivo
and in vitro assays were performed to analyse the
viability of these constructs and their capacity to
generate a terminally differentiated skin.
The correct formation of the dermoepidermal
junction of the skin was confirmed by labelling
with an antibody against human collagen VII
(figure 4(B) green staining), the protein forming the
anchoring fibrils that bind together epidermis and
dermis.
From the immunohistochemical
point of view, K14 is a well-established marker of
epidermal basal cells as shown
*Este metodo é mais fácil em vez de imprimir um grande numero cellular e acellular em camadas, o que temos é depossição simultaneal de fibroblastos, plasma humano e cacl2 e por fim uma mono layer de hKCs
staining with dermal and epidermal
markers)
The results
showed that the generated skin had correct architecture
Secondly, the structure and functionality of the
printed human skin was further analysed on skinhumanized
Mice
and several differentiation markers such
as keratin 5 (a marker of proliferative basal keratinocytes),
human vimentin (a marker of hFBs), humancollagen
type VII (a marker of dermoepidermal basal
membrane), keratin 10 (a marker of suprabasal differentiated
keratinocytes) and human-filaggrin (a marker
of keratinocyte terminal differentiation)
Sobre os capilares This finding represents additional evidence of the
functionality of our skin regenerated from human bioprinted
equivalents.