Limits...
Tissue Engineering the Cornea: The Evolution of RAFT.

Levis HJ, Kureshi AK, Massie I, Morgan L, Vernon AJ, Daniels JT - J Funct Biomater (2015)

Bottom Line: This review will detail how we have refined the simple engineering technique of plastic compression of collagen to a process we now call Real Architecture for 3D Tissues (RAFT).The RAFT production process has been standardised, and steps have been taken to consider Good Manufacturing Practice compliance.The evolution of this process has allowed us to create biomimetic epithelial and endothelial tissue equivalents suitable for transplantation and ideal for studying cell-cell interactions in vitro.

View Article: PubMed Central - PubMed

Affiliation: Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK. h.levis@ucl.ac.uk.

ABSTRACT
Corneal blindness affects over 10 million people worldwide and current treatment strategies often involve replacement of the defective layer with healthy tissue. Due to a worldwide donor cornea shortage and the absence of suitable biological scaffolds, recent research has focused on the development of tissue engineering techniques to create alternative therapies. This review will detail how we have refined the simple engineering technique of plastic compression of collagen to a process we now call Real Architecture for 3D Tissues (RAFT). The RAFT production process has been standardised, and steps have been taken to consider Good Manufacturing Practice compliance. The evolution of this process has allowed us to create biomimetic epithelial and endothelial tissue equivalents suitable for transplantation and ideal for studying cell-cell interactions in vitro.

No MeSH data available.


Related in: MedlinePlus

Evolution of the RAFT process hardware. (A) Individual cassette for upward confined compression method; (B) Paper rolls and weights used for 12 well plate confined compression method using upward flow; (C) Commercially available RAFT kits including reagents, plates and plate heater (image reprinted with permission of TAP Biosystems); (D) 24-well plate array of HPAs.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4384100&req=5

jfb-06-00050-f003: Evolution of the RAFT process hardware. (A) Individual cassette for upward confined compression method; (B) Paper rolls and weights used for 12 well plate confined compression method using upward flow; (C) Commercially available RAFT kits including reagents, plates and plate heater (image reprinted with permission of TAP Biosystems); (D) 24-well plate array of HPAs.

Mentions: In collaboration with a SME (small and medium sized enterprise; TAP Biosystems), we developed what we now refer to as the Real Architecture For 3D Tissues (RAFT) process by extensive modification of the original PC process from a variable hand-made research method [20] to an improved, reproducible process suitable for clinical application [28]. The differences between the three iterations of the process are summarised in Table 2. The original unconfined compression (UC) process was not tightly controlled and therefore not compatible for use in a GMP clean room facility. In particular, this process had a greater potential for production of aerosols and particulates, which is not ideal for a GMP compliant approach. Additionally, the final product had inconsistent dimensions due to fluid loss in various directions. To overcome these issues, the collagen hydrogel mixture was cast, set and compressed in a confined manner using a custom-made cassette or 12-well plate format (Figure 3A,B). The modification involved a change in the direction of fluid removal to one of upward flow using a rolled filter paper absorber and other blotting elements placed on the top surface of collagen hydrogels for 15 min at room temperature (Figure 2B and Table 2). As a weight was applied, hydrogels still underwent compression but this time it was a confined compression (CC), which reduced the risk of aerosol and particulate production. Following compression, RAFT TEs were ready in a multi-well plate format or an individual cassette for immediate analysis or subsequent culture of cells. This reduced the risk of damaging RAFT TEs during handling or transfer from one vessel to another as was required for the original PC method.


Tissue Engineering the Cornea: The Evolution of RAFT.

Levis HJ, Kureshi AK, Massie I, Morgan L, Vernon AJ, Daniels JT - J Funct Biomater (2015)

Evolution of the RAFT process hardware. (A) Individual cassette for upward confined compression method; (B) Paper rolls and weights used for 12 well plate confined compression method using upward flow; (C) Commercially available RAFT kits including reagents, plates and plate heater (image reprinted with permission of TAP Biosystems); (D) 24-well plate array of HPAs.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384100&req=5

jfb-06-00050-f003: Evolution of the RAFT process hardware. (A) Individual cassette for upward confined compression method; (B) Paper rolls and weights used for 12 well plate confined compression method using upward flow; (C) Commercially available RAFT kits including reagents, plates and plate heater (image reprinted with permission of TAP Biosystems); (D) 24-well plate array of HPAs.
Mentions: In collaboration with a SME (small and medium sized enterprise; TAP Biosystems), we developed what we now refer to as the Real Architecture For 3D Tissues (RAFT) process by extensive modification of the original PC process from a variable hand-made research method [20] to an improved, reproducible process suitable for clinical application [28]. The differences between the three iterations of the process are summarised in Table 2. The original unconfined compression (UC) process was not tightly controlled and therefore not compatible for use in a GMP clean room facility. In particular, this process had a greater potential for production of aerosols and particulates, which is not ideal for a GMP compliant approach. Additionally, the final product had inconsistent dimensions due to fluid loss in various directions. To overcome these issues, the collagen hydrogel mixture was cast, set and compressed in a confined manner using a custom-made cassette or 12-well plate format (Figure 3A,B). The modification involved a change in the direction of fluid removal to one of upward flow using a rolled filter paper absorber and other blotting elements placed on the top surface of collagen hydrogels for 15 min at room temperature (Figure 2B and Table 2). As a weight was applied, hydrogels still underwent compression but this time it was a confined compression (CC), which reduced the risk of aerosol and particulate production. Following compression, RAFT TEs were ready in a multi-well plate format or an individual cassette for immediate analysis or subsequent culture of cells. This reduced the risk of damaging RAFT TEs during handling or transfer from one vessel to another as was required for the original PC method.

Bottom Line: This review will detail how we have refined the simple engineering technique of plastic compression of collagen to a process we now call Real Architecture for 3D Tissues (RAFT).The RAFT production process has been standardised, and steps have been taken to consider Good Manufacturing Practice compliance.The evolution of this process has allowed us to create biomimetic epithelial and endothelial tissue equivalents suitable for transplantation and ideal for studying cell-cell interactions in vitro.

View Article: PubMed Central - PubMed

Affiliation: Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK. h.levis@ucl.ac.uk.

ABSTRACT
Corneal blindness affects over 10 million people worldwide and current treatment strategies often involve replacement of the defective layer with healthy tissue. Due to a worldwide donor cornea shortage and the absence of suitable biological scaffolds, recent research has focused on the development of tissue engineering techniques to create alternative therapies. This review will detail how we have refined the simple engineering technique of plastic compression of collagen to a process we now call Real Architecture for 3D Tissues (RAFT). The RAFT production process has been standardised, and steps have been taken to consider Good Manufacturing Practice compliance. The evolution of this process has allowed us to create biomimetic epithelial and endothelial tissue equivalents suitable for transplantation and ideal for studying cell-cell interactions in vitro.

No MeSH data available.


Related in: MedlinePlus