作者感谢国家自然科学基金（批准号12125205，12072316，12132014）和中国博士后科学基金（批准号：2022M712754）的支持。

1. 理论准备
<ol><li>定义三个参数：液体吸光度 （Al）、固体吸光度 （As） 和阈值时间 （tT）17。</li>
	<li>根据公式 1，使用这三个参数17 重写传统的 Jacobs 工作曲线： <img alt="Equation 1" src="/files/ftp_upload/65277/65277eq01.jpg" style="margin: auto;">（公式1） 这里，t H是单层的固化时间，H 是单层的高度。</li>
</ol>2. 参数采集
<ol><li>使用配备温度控制元件的流变仪测量生物墨水的阈值时间。<ol><li>使用365nm光源曝光流变仪的测试平台，使光强度达到一定值。</li>
		<li>设置流变仪以获取 300 秒内的时间模量数据，并通过流变仪软件中的时间设置选项每 0.3 秒获取每个数据点。点击流变仪的“开始测试”按钮开始测试，同时点击光源的“开始”按钮。</li>
		<li>从曝光开始计数，当储能模量数据等于损耗模量数据时，相应的时间被识别为阈值时间。手动录制。</li>
	</ol></li>
	<li>按照上文工作17所示建造吸光度测试设备。使用两个上下载玻片夹紧厚度为500μm的环形印刷结构（5毫米内径，10毫米外径），使环的内圈形成一个腔室。将腔室放在光强计的测试区域，并设置光源以暴露腔室区域。 注： 图1 为光流变测试结果和数据处理结果以及吸光度测试设备的示意图。<ol><li>当测试室未充满来自吸光度测试设备的材料的入射光强度（I i）时，通过读取测试设备的光强计的显示来测量入射光强度（Ii）。</li>
		<li>用 10 μLof 生物墨水填充测试室。</li>
		<li>用生物墨水将测试室暴露在 365 nm 的紫外线下。通过读取测试设备的光强计的显示，从吸光度测试设备获得光强度（Ilh）。</li>
		<li>当值不再变化时，通过读取测试设备的光强计的显示，从吸光度测试设备获得生物墨水固化时的光强度（Ish）。这个值就是固体吸光度，我什。</li>
		<li>使用公式2和3计算液体吸光度和固体吸光度： <img alt="Equation 2" src="/files/ftp_upload/65277/65277eq02.jpg" style="margin: auto;">     等式2 <img alt="Equation 3" src="/files/ftp_upload/65277/65277eq03.jpg" style="margin: auto;">     等式3</li>
	</ol></li>
	<li>根据得到的参数得到雅各布斯工作曲线。</li>
</ol><img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/65277/65277fig01.jpg"> 图1：测试结果和设备 。 （A）光流变测试结果和数据处理结果示意图。（二）吸光度检测设备。该图经Li等人许可修改17。 <a href="https://www.jove.com/files/ftp_upload/65277/65277fig01large.jpg" target="_blank">请点击此处查看此图的大图。</a>
3. 连续 DLP 打印参数设置
<ol><li>使用DLP软件实现DLP打印，并在软件中设置打印参数如下。</li>
	<li>在软件的参数设置中将第一个单层的曝光时间设置为阈值时间（tT）。<ol><li>根据公式1计算固化10μm厚材料的曝光时间，并减去阈值时间，以获得固化单层的实际曝光时间。</li>
	</ol></li>
	<li>在软件的参数设置中将相邻层之间的时间间隔设置为 0 s。</li>
	<li>通过单击打印软件中的 “开始” 按钮启动打印机。打印过程结束后，单击打印软件中的 “停止” 按钮完成打印。</li>
</ol>

用于连续 DLP 打印的生物墨水特性的定量表征

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作者没有什么可透露的。

该协议的关键步骤在第2节中描述。有必要将光流变测试中使用的光强度与实际测试中的印刷光强度统一起来.吸光度测试设备是最重要的部分。试验箱的形状应与光强计的感光区域相同。由于材料在整个紫外光照射过程中不断变化的特性，光强度需要不断变化6。根据公式1中液体吸光度和固体吸光度的定义，简化了固化过程。将曝光开始时的数据作为液体吸光度，将光强恒定时的...

组织工程1 在器官修复领域很重要。由于缺乏器官捐献，一些疾病，如肝衰竭和肾衰竭，不能很好地治愈，许多患者没有得到及时的治疗2。具有器官所需功能的类器官可以解决因缺乏器官捐献而引起的问题。类器官的构建取决于生物打印技术的进步和发展3.
与挤出型生物打印4和喷墨型生物打印5相比，数字光处理（DLP）生物打印方法的打印速度和打印精度更高6，7。挤出式方法的打印模块是逐行的，而喷墨式方法的打印模块是逐点的，效率低于DLP生物打印的逐层打印模块。在DLP生物打印中，将调制紫外线（UV）照射到整个材料层以固化一层以及图像的特征尺寸决定了DLP打印的准确性。这使得DLP技术非常高效8，9，10。由于紫外光的过度固化，固化时间和打印尺寸之间的精确关系对于高精度DLP生物打印非常重要。此外，连续DLP打印是对DLP打印方法的改进，可以大大提高打印效率11，12，13。对于连续 DLP 打印，精确的打印条件是最重要的因素。
固化时间与印刷尺寸之间的关系称为雅各布工作曲线，广泛用于DLP印刷14，15，16。获得关系的传统方法是将材料暴露一定时间并测量固化厚度，以获得有关曝光时间和固化厚度的数据点。重复此操作至少五次并拟合数据点可获得 Jacobs 工作曲线。但是，这种方法有明显的缺点;它需要消耗大量的材料才能实现固化，结果高度依赖于打印条件，DLP生物打印中使用的生物墨水昂贵且稀有，并且生物墨水的成型性通常不好，这可能导致固化厚度的测量不准确。
本文根据生物墨水的物理性质提供了一种获得固化关系的新方法。使用此理论可以优化连续DLP打印。该方法可用于更快、更准确地获得固化关系;因此，可以更好地确定连续DLP固化。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Brilliant Blue</td>
			<td>Aladdin (Shanghai, China).</td>
			<td>6104-59-2&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>DLP software</td>
			<td>Creation Workshop</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Lithium phenyl-2,4,6-trimethylbenzoylphosphinate</td>
			<td></td>
			<td>N/A</td>
			<td>LAP; synthesized</td>
		</tr>
		<tr>
			<td>Light source</td>
			<td>OmniCure</td>
			<td>https://www.excelitas.com/product-category/omnicure-s-series-lamp-spot-uv-curing-systems</td>
			<td>365 nm</td>
		</tr>
		<tr>
			<td>Polyethylene (glycol) diacrylate</td>
			<td>Sigma-Aldrich</td>
			<td>455008</td>
			<td>PEGDA Mw ~700</td>
		</tr>
		<tr>
			<td>Rheometer&#160;</td>
			<td>Anton Paar, Austria</td>
			<td>MCR302</td>
			<td></td>
		</tr>
	</tbody>
</table>

quantitative characterization of liquid photosensitive bioink properties for continuous digital light processing based printing

生物墨水的精确印刷制造是组织工程的先决条件;Jacobs工作曲线是确定数字光处理（DLP）精确打印参数的工具。然而，工作曲线的获取浪费了材料，并且对材料的成型性要求很高，不适合生物材料。此外，由于多次暴露而导致的细胞活性降低和由于重复定位而导致的结构形成失败都是传统DLP生物打印中不可避免的问题。本工作介绍了一种获取工作曲线的新方法以及基于这种工作曲线的连续DLP打印技术的改进过程。这种获得工作曲线的方法基于生物材料的吸光度和光流变特性，其不依赖于生物材料的可成形性。通过分析工作曲线改进打印工艺而获得的连续DLP打印工艺，使打印效率提高了十倍以上，大大提高了细胞的活性和功能，有利于组织工程的发展。

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.

作者聚焦：基于连续数字光处理的印刷中液体光敏生物墨水特性的定量表征  

基于连续数字光处理的印刷中液体光敏生物墨水特性的定量表征

本文展示了一种获取固化参数的新方法，并介绍了一种实现连续DLP打印的新方法，展示了该方法在确定工作曲线方面的效率。
我们在DLP打印中使用了三种不同的材料来验证本文介绍的方法获得的理论工作曲线的准确性。材料是20%（v/v）聚乙二醇二丙烯酸酯（PEGDA），0.5%（w/v）苯基-2，4，6-三甲基苯甲酰次膦酸锂（LAP），具有不同浓度的紫外线吸收剂-0.1%（w / v），0.15%（w / v）?...

Watch this Scientific Journal Video about Quantitative Characterization of Liquid Photosensitive Bioink Properties for Continuous Digital Light Processing Based Printing at JoVE.com

本研究使用温度和材料组成来控制屈服应力流体的屈服应力特性。油墨的固态可以保护打印结构，液体状状态可以连续填充打印位置，实现极软生物墨水的数字光处理3D打印。

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

我的研究主要涉及DLP 3D生物打印和组织工程。我们尝试优化和改进DLP打印工艺和配方理论，使打印的组织工程支架能够更好地满足实际的临床应用需求。现有光固化材料的印刷条件依靠手工实验，通过多次实验的数据馈送获得。这样的实验浪费了材料，降低了印刷效率。我构建了一条理论工作曲线，并仅根据材料的物理性质确定了DLP打印金字塔。提出了将动力学两种最佳概念应用于DLP打印中，以实现极软材料的复杂尺寸结构的DLP格式。该方法可以提高确定光固化材料打印条件的效率。该技术可为光固化材料的研发和这些材料的精确打印提供技术支持。

quantitative-characterization-liquid-photosensitive-bioink-properties

Research

JoVE Journal

Bioengineering

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

585 次观看.  Zhejiang University. 我的研究主要涉及DLP 3D生物打印和组织工程。我们尝试优化和改进DLP打印工艺和配方理论，使打印的组织工程支架能够更好地满足实际的临床应用需求。现有光固化材料的印刷条件依靠手工实验，通过多次实验的数据馈送获得。这样的实验浪费了材料，降低了印刷效率。我构建了一条理论工作曲线，并仅根据材料的物理性质确定了DLP打印金字塔。提出了将动力学两种最?...

视频: 作者聚焦：基于连续数字光处理的印刷中液体光敏生物墨水特性的定量表征  

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.