﻿parameter acquisition for dlp printing

연속 DLP 프린팅을 위한 Bioink 특성의 정량적 특성 분석

Tissue engineering1 is important in the field of organ repair. Due to the lack of organ donation, some diseases, such as liver failure and kidney failure, cannot be cured well, and many patients do not receive timely treatment2. Organoids with the required function of the organs may solve the problem caused by the lack of organ donation. The construction of organoids depends on the progress and development of bioprinting technology3.
Compared with extrusion-type bioprinting4 and inkjet-type bioprinting5, the printing speed and printing accuracy of the digital light processing (DLP) bioprinting method are higher6,7. The printing module of the extrusion-type method is line-by-line, while the printing module of the inkjet-type method is dot-by-dot, which is less efficient than the layer-by-layer printing module of DLP bioprinting. The modulated ultraviolet (UV) light exposure to a whole layer of material to cure a layer in DLP bioprinting and the feature size of the image determines the accuracy of DLP printing. This makes DLP technology very efficient8,9,10. Due to overcuring of the UV light, the precise relationship between the curing time and the printing size is important for high-accuracy DLP bioprinting. Furthermore, continuous DLP printing is a modification of DLP printing method that can greatly improve the printing efficiency11,12,13. For continuous DLP printing, precise printing conditions are the most important factors.
The relationship between the curing time and the printing size is called the Jacobs working curve, which is widely used in DLP printing14,15,16. The traditional method to obtain the relationship is to expose the material for a certain time and measure the curing thickness to obtain a data point about the exposure time and curing thickness. Repeating this operation at least five times and fitting the data points obtains the Jacobs working curve. However, this method has obvious disadvantages; it needs to consume a lot of material to achieve the curing, the results are highly dependent on the printing conditions, the bioinks used in DLP bioprinting are expensive and rare, and the formability of the bioinks is usually not good, which can lead to inaccurate measurements of curing thickness.
This article provides a new method to obtain the curing relationship according to the physical properties of the bioink. Using this theory can optimize continuous DLP printing. This method can be used to obtain the curing relationship more quickly and accurately; the continuous DLP curing can therefore be better determined.

저자 스포트라이트: 연속 디지털 광 처리 기반 인쇄를 위한 액체 감광성 바이오잉크 특성의 정량적 특성 분석  

연속 디지털 광 처리 기반 인쇄를 위한 액체 감광성 Bioink 특성의 정량적 특성 분석

My research mainly involves DLP 3D bio printing and tissue engineering. We try to optimize and improve the DLP printing process and formula theory, so that the printed tissue engineering scaffold can better meet the actual clinic application needs. The printing conditions of the existing light curable materials rely on manual experiments and are obtained by feeding the data of multiple performing experiments.Such experiments waste material and reduced printing efficiency. I constructed a theoretical working curve and determined the DLP printing pyramids only based on the physical properties of the material. Dynamics both best concept is proposed to be applied in DLP printing to realize DLP format of complex dimensional structures of extremely soft materials.This method can improve the efficiency of determining the printing conditions of photo curable materials. This technology can provide technical support for the research and development of photo curable materials and the accurate printing of these materials.

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Parameter Acquisition for DLP Printing  

DLP 인쇄를 위한 파라미터 획득

온도 조절 요소가 있는 레오미터를 사용하여 바이오잉크의 임계 시간을 측정하는 것으로 시작합니다. 365나노미터 광원을 활용하여 레오미터의 테스트 플랫폼을 노출시키고 광도를 특정 값으로 설정합니다. 레오미터 소프트웨어에서 시간 설정 옵션으로 이동하여 0.3초마다 각 데이터 포인트를 채취하여 300개 데이터 포인트에 대한 시간 모듈리 데이터를 획득하도록 레오미터를 설정합니다.레오미터 소프트웨어에서 테스트 시작 버튼을 클릭하여 테스트를 시작합니다. 동시에 광원의 시작 버튼을 클릭합니다. 임계값 시간을 계산하려면 저장 탄성률 데이터가 손실 탄성률 데이터와 같을 때 노출 시작부터 해당 시간 계산을 기록합니다.그런 다음 상부 및 하부 유리 슬라이드와 링 모양의 인쇄 구조를 사용하여 흡광도 테스트 장비를 구축합니다. 링의 내부 원이 챔버를 형성하도록 유리 슬라이드 사이에 링을 고정하십시오. 광도 측정기의 테스트 영역에 챔버를 놓고 광원을 설정하여 챔버 영역을 노출시킵니다.테스트 챔버가 흡광도 테스트 장비의 재료로 채워지지 않은 경우 광 강도 측정기의 디스플레이를 읽어 입사광 강도 II를 측정합니다. 다음으로, 테스트 챔버를 10 마이크로 리터의 바이오 잉크로 채 웁니다. 바이오 잉크가 들어있는 테스트 챔버를 365 나노 미터의 자외선에 노출시킵니다.디스플레이를 읽어 광도 IIH를 구합니다. 광도 측정기에서 값이 더 이상 변경되지 않으면 디스플레이를 읽고 바이오 잉크가 경화될 때의 광도를 얻습니다. 값은 고체 흡광도 ISH입니다.

Research

JoVE Journal

Bioengineering

﻿Parameter Acquisition for DLP Printing

188 조회수.  Zhejiang University. 온도 조절 요소가 있는 레오미터를 사용하여 바이오잉크의 임계 시간을 측정하는 것으로 시작합니다. 365나노미터 광원을 활용하여 레오미터의 테스트 플랫폼을 노출시키고 광도를 특정 값으로 설정합니다. 레오미터 소프트웨어에서 시간 설정 옵션으로 이동하여 0.3초마다 각 데이터 포인트를 채취하여 300개 데이터 포인트에 대한 시간 모듈리 데이터를 획득하도록 레오미터...

비디오: Parameter Acquisition for DLP Printing  

Quantitative Characterization of Liquid Photosensitive Bioink Properties for Continuous Digital Light Processing Based Printing

Precise printing fabrication of bioinks is a prerequisite for tissue engineering; the Jacobs working curve is the tool to determine the precise printing parameters of digital light processing (DLP). However, the acquisition of working curves wastes materials and requires high formability of materials, which are not suitable for biomaterials. In addition, the reduction of cell activity due to multiple exposures and the failure of structural formation due to repeated positioning are both unavoidable problems in conventional DLP bioprinting. This work introduces a new method of obtaining the working curve and the improvement process of continuous DLP printing technology based on such a working curve. This method of obtaining the working curve is based on the absorbance and photorheological properties of the biomaterials, which do not depend on the formability of the biomaterials. The continuous DLP printing process, obtained from improving the printing process by analyzing the working curve, increases the printing efficiency more than tenfold and greatly improves the activity and functionality of cells, which is beneficial to the development of tissue engineering.

This study uses temperature and material composition to control the yield stress properties of yield stress fluids. The solid-like state of the ink can protect the printing structure, and the liquid-like state can continuously fill the printing position, realizing the digital light processing 3D printing of extremely soft bioinks.

Precise printing fabrication of bioinks is a prerequisite for tissue engineering; the Jacobs working curve is the tool to determine the precise printing ...

연구

생체공학

Begin by measuring the threshold time of the bio-ink using a rheometer with a temperature control element. Utilize a 365 nanometer light source to expose the testing platform of the rheometer and set the light intensity to a certain value. In the rheometer software, go to the time settings option and set the rheometer to acquire the time moduli data for 300 data points with each data point taken every 0.3 seconds.Click the start test button on the rheometer software to begin the test. Simultaneously, click the start button of the light source. To calculate the threshold time, record the corresponding time counting from the start of exposure when the storage modulus data is equal to the loss modulus data.Then build the absorbance test equipment by using upper and lower glass slides and the ring-shaped printed structure. Clamp the ring between the glass slides so that the inner circle of the ring forms the chamber. Place the chamber on the test area of the light intensity meter and set the light source to expose the chamber area.When the test chamber is not filled with material from the absorbance test equipment, measure the incident light intensity, II, by reading the display of the light intensity meter. Next, fill the test chamber with 10 microliters of bio-ink. Expose the test chamber containing bio-ink to ultraviolet light at 365 nanometers.Obtain the light intensity, IIH, by reading the display. When the value no longer changes on the light intensity meter, read the display to obtain the light intensity when the bio-ink is cured. The value is the solid absorbance, ISH.

Continuous DLP Printing Parameter Settings

To achieve digital light processing or DLP printing, start by using a DLP software. In the parameter settings, set the exposure time of the first single layer to the threshold time. Calculate the exposure time of curing 10 micrometer thick materials according to this equation and subtract the threshold time to obtain the real exposure time for curing a single layer.In the software's parameter settings, set the time interval between adjacent layers to zero seconds. Start the printer by clicking the start button in the printing software. When the printing process ends, finish printing by clicking the stop button.This protocol demonstrates that the continuous DLP printing method can accurately calculate the theoretical working curves of different materials. A high degree of coincidence was observed between theoretical predictions and real printing results for three distinct materials. Compared to the traditional DLP printing method, this method showed improvement in printing efficiency, with decreasing printing layer thickness.Furthermore, a tenfold increase in curing efficiency was observed compared to traditional DLP printing, showing that the continuous DLP printing method can simultaneously achieve high efficiency and high fidelity.