这项研究得到了堪萨斯州立大学的支持。这项研究的一部分是在纳米材料科学中心进行的, 这是由科学用户设施司、美国能源部、能源科学办公室主办的橡树岭国家实验室。

1. 飞碟乙PVDMA 合成20
<ol><li>飞碟宏链转移剂的合成 (宏 CTA)<ol>
<li>使用250毫升的圆底反应ﬂask 装有聚四氟乙烯涂层的磁力搅拌棒。</li>
		<li>将14.2 克甲基丙烯酸缩水甘油 (142.18 克/摩尔) 与490.8 毫克2氰基-2-丙基月桂 trithiocarbonate (CPDT) (346.63 克/摩尔) 相结合, 和87.7 毫克的 2,2′-偶 (4-甲氧基 24-二甲基 valeronitrile) (V-70) (308.43 克/摩尔) (摩尔比 CPDT: V-70 =5:1), 和苯 (100 毫升) 的空气自由圆底烧瓶。</li>
		<li>用氩气搅拌反应混合物30分钟。随后把溶液在温度控制的油浴在30°c 和反应 18 h。 注: 宏观 CTA 的靶分子量为1万克/摩尔. 18 小时被确定为达到合理转换所需的时间。聚合物溶液的颜色为透明浅黄色。</li>
		<li>18小时后, 将圆底烧瓶浸入液体 N2, 终止反应。</li>
		<li>将聚合物/苯 (~ 100 毫升) 的淡黄色溶液倒入400毫升己烷, 沉淀聚合物。</li>
		<li>搅拌混合物5分钟沉淀将在烧杯底部结算, 并通过过滤回收。</li>
		<li>在真空下一夜之间干燥沉淀。然后稀释400毫升的四氢呋喃 (THF)。在己烷中重新沉淀。</li>
		<li>用氩在一夜之间再干这个新沉淀。 注: 宏 CTA 是一种优良的黄色粉末。反应产物的产率将为43.8%。飞碟宏观 CTA 的 Mn是7990克/摩尔与多分散性 (PDI) 1.506 (MW = 12030 克/摩尔)。</li>
	</ol>
</li>
	<li>飞碟-bPVDMA 的合成<ol>
<li>在减压下, 将 VDMA 蒸馏, 并保留中间分数 (~ 70%) 供使用。 注: 这是去除聚合抑制剂所必需的。蒸馏装置附着在 Schlenk 线上, 空气密封阀部分打开至真空线。最小的热量使用 varistat 和加热地幔, 直到 VDMA 单体开始蒸馏超过每秒1滴率。</li>
		<li>将 2-乙烯基44二甲基 azlactone (VDMA) (139.15 克/摩尔) 单体 (10.436 克) 与飞碟 macroCTA (1.669 克) 相结合, V-70 (14.5 毫克; 飞碟-macroCTA: V-70 = 3:1) 和苯 (75.0 毫升) 在单颈部250毫升圆底反应中的摩尔比, ﬂask 配有聚四氟乙烯涂层磁力搅拌棒。 注: 分子量信息, PVDMA: 139.15 克/摩尔, 飞碟-macroCTA: 12030 克/摩尔, 苯: 78.11 克/摩尔。</li>
		<li>德加高纯度氩气搅拌30分钟, 然后放入油浴在32°c 为 18 h。</li>
		<li>通过将圆底烧瓶浸入液体 N2来终止反应。</li>
		<li>将聚合物沉淀三倍, 并在室温下在真空下干燥。</li>
		<li>根据 Lokitz等程序, 采用尺寸排除色谱法 (参见材料表), 对产品的分子量和质量进行了表征。20。尺寸排除色谱仪 (S) 配备三 PLgel 5 µm 混合 C 柱 (300 x 7.5 毫米) 系列, 一个折射率探测器 (波长 = 880 nm), 光电二极管阵列探测器, 多角度光散射 (加工) 探测器 (波长 = 660 nm), 和粘度计 (见材料表)。 注: 在本手稿中进行的所有实验都采用了飞碟和 PVDMA 块长度分别为56和175的产品。嵌段共聚物的分子量为37620克/摩尔, 而 PDI 为1.16。</li>
	</ol>
</li>
</ol>2. 在硅基板上生成派瑞林模具图案
<ol><li>派瑞林涂料<ol>
<li>油脂实验硅晶片在水中的 50%, 丙酮在5分钟后, 超声波在50% 的异丙醇 (IPA) 在水中5分钟。</li>
		<li>用去离子 (DI) 水冲洗硅片, 用氮气吹干。</li>
		<li>使用派瑞林涂布机在4英寸硅片上沉积 80 nm 和1µm 厚派瑞林 N (见材料表)。 注: 使用表面轮廓来表征派瑞林薄膜的厚度 (见材料表)。<ol>
<li>对每个派瑞林涂装系统进行派瑞林二聚体的派瑞林膜厚度标定。 注: 在目前的系统中, 需要80毫克和 ~ 1000 毫克派瑞林 N 二聚体分别获得 80 nm 和1µm 膜厚度 (根据所获得的校准曲线)。</li>
			<li>在派瑞林涂布机的操作过程中使用以下设置: 压力:80 mTorr, 持续时间: 1 小时, 炉膛温度: 690 °c, 蒸发器温度: 160 摄氏度。</li>
		</ol>
</li>
	</ol>
</li>
	<li>光刻<ol>
<li>在烤箱烘烤晶片在100°c 20 分钟;然后让晶片在室温下再坐3分钟。 注意: 额外的等待时间提高了光刻胶的附着力。</li>
		<li>添加2毫升的正光刻胶 (见材料表), 并免除在派瑞林涂层晶片的中心。自旋涂层的硅片在 3000 rpm 三十年代。 注: 自旋涂层必须在罩下完成。</li>
		<li>等待1分钟, 烘烤硅片上的热板在105°c 1 分钟。</li>
		<li>在掩码对准系统中加载光掩模 (参见材料表)。曝光硅片到紫外光 (λ = 325 毫微米) 为十年代以药量 65 mJ/cm2。</li>
		<li>让晶片在室温下再坐5分钟。</li>
		<li>通过淹没在开发者 (见材料表) 解决方案, 开发硅片2分钟. 用去离子水冲洗晶片, 然后用 N2干。在引擎盖下面做这个。 注意: 在开发后, 光刻胶似乎完全从暴露于紫外线的区域中移除。使用光学显微镜 (见材料表) 来验证晶片。</li>
	</ol>
</li>
	<li>反应离子蚀刻<ol>
<li>使用一种反应离子蚀刻工具 (见材料表) 用氧等离子体蚀刻已开发的晶片。</li>
		<li>应用氧流速为50厘米3/分钟在室压力 20 mTorr。</li>
		<li>对于派瑞林薄膜厚度为1µm, 使用 50 w 的射频功率和电感耦合等离子体 (ICP) 功率 500 W 的100s 是消除暴露派瑞林从图案的区域。这对应于派瑞林蚀刻率 1.0-1.15 µm/分钟。</li>
		<li>对于派瑞林厚度为80毫微米, 使用 50 w 的射频功率和 ICP 功率为 200 w, 五十五年代, 以消除被暴露的派瑞林从图案的区域。这对应于派瑞林蚀刻率570-620 毫微米/分钟。 注: 为了有效的派瑞林去除, 确定每一个被浸蚀系统的派瑞林蚀刻速率。</li>
		<li>用光学显微镜检查蚀刻衬底。在派瑞林完全从暴露的区域中移除后, 硅表面会出现发亮。</li>
		<li>使用曲面轮廓验证蚀刻深度 (请参阅材料表)。</li>
	</ol>
</li>
</ol>3. 派瑞林升降程序
<ol><li>高分子溶液的制备<ol>
<li>将飞碟 PVDMA溶于氯仿 (1%)。氯仿应无水, 以防止 azlactone 组的水解。 注: 氯仿是首选溶剂, 因为它具有较高的溶解度的聚合物, 允许更均匀的表面沉积的单一聚合物链相比, 其他有机溶剂25。</li>
	</ol>
</li>
	<li>清洁派瑞林钢板蜡纸与血浆清洁剂<ol>
<li>打开等离子清洗器 (见材料表) 的主电源, 并把派瑞林涂层的基底在等离子清洗室。</li>
		<li>打开真空泵, 将空气放在室内, 直到压力表小于 400 mTorr。</li>
		<li>稍微打开计量阀, 让空气进入等离子清洗器, 直到压力表显示 800-1000 mTorr。</li>
		<li>选择高模式 RF, 并暴露基体3分钟。</li>
		<li>在加工结束时, 关闭射频电源和真空泵。</li>
		<li>关闭等离子清洗器, 取出基板。 注: 在等离子清洗后, 表面显示亲水性行为 (图 1B)。等离子清洗前后裸硅表面的水接触角分别 27°2°和0°。</li>
	</ol>
</li>
	<li>飞碟-PVDMA、退火和超声波在派瑞林模具上的自旋涂层<ol>
<li>在十五年代使用自旋涂布机 (见材料表) 时,立即用100µL 1% 飞碟-PVDMA 在无水氯仿上自旋涂层。 注: 在1-2 吹打内进行自旋涂层聚合物溶液, 以尽量减少快速氯仿蒸发引起的薄膜不均匀性。</li>
		<li>在真空烘箱中, 将聚合物薄膜退火110摄氏度 (见材料表) 18 小时。 注: 退火允许聚合物相离析和表面附着的 GMA 块到表面26。<ol>
<li>退火后, 通过测量基体的接触角来表征聚合物涂层。曲面显示 75°±1°的接触角 (图 1C)20。</li>
		</ol>
</li>
		<li>油脂实验20毫升丙酮或氯仿中的基质, 去除派瑞林层和任何 physisorbed 聚合物。 注: 使用以下超声波条件: 超音波功率, 284 W;工作频率, 40 赫 (见材料表)。 注: 派瑞林还可以通过在承印物的边缘涂上一条透明胶片, 然后将胶带拉走27。</li>
		<li>将基底置于真空中, 干燥, 直到表征。</li>
	</ol>
</li>
</ol><img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57562/57562fig1.jpg"> 图 1: 处理过的硅基板的接触角测量。(A)裸硅, (B)等离子清洗硅, (C)自旋涂层硅与飞碟-B-PVDMA (退火后和超声波的氯仿)。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57562/57562fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
4. 飞碟-PVDMA 界面定向装配程序
注: 本程序可在含有化学惰性背景 (4.1 节) 或生物惰性背景 (4.2 节) 的基板上执行, 具体取决于应用。
<ol><li>硅基材化学惰性背景的制备<ol>
<li>使用氧气等离子清洁剂清洁裸硅 (3.2 节)。</li>
		<li>吸管100µL 的氯 (1 小时, 1 小时, 2 小时, 2 h perfluorooctyl) 硅烷 (TPS) 到一个培养皿上, 并将硅基板置于真空干燥旁边的培养皿。</li>
		<li>将真空 (-750 乇) 用于化学气相沉积 (CVD) 1 小时。 注意: TPS 是剧毒的, CVD 过程应该在通风罩内进行。 注: 1 h 后, 基体显示疏水性行为。109°±3°的接触角通常是在 CVD 过程之后测量的。TPS 薄膜的厚度是 1.5, 0.5 纳米。 注: TPS 阻止活性表面氧化物与飞碟-PVDMA 的反应。</li>
		<li>用派瑞林 (1 µm 厚度) 涂上晶片。执行光刻和反应离子蚀刻产生派瑞林模式 (第2节) 和蚀刻离开 TPS 层在暴露的区域。</li>
	</ol>
</li>
	<li>在硅基板上制备聚乙二醇 (PEG) 背景。<ol>
<li>使用氧气等离子清洗剂3分钟清洁裸硅基板 (3.2 节)。</li>
		<li>对1小时的 TPS 进行 CVD (4.1.2 节)。</li>
		<li>将基质浸入 0.7% Pluronic F-127 的超纯水中, 在18小时内产生一个 PEG 层, 表面28,29。 注: Pluronic 在两个 PEG 链之间含有疏水性聚丙烯氧化物 (PPO) 聚合物块。在 PEG 链接触到溶液28时, PPO 块将聚合物锚定在 TPS 表面。</li>
		<li>用100毫升的超纯水冲洗和冲洗基体5分钟。</li>
		<li>用派瑞林涂布机在4寸硅片上沉积 80 nm 和1µm 厚派瑞林 N。</li>
		<li>执行光刻和反应离子蚀刻产生派瑞林模式 (第2节)。</li>
	</ol>
</li>
	<li>超声波、飞碟-硼PVDMA 聚合物的自旋涂层及基体退火<ol>
<li>油脂实验化学惰性 (TPS) 基板 (4.1 节) 或 PEG 功能基底 (4.2 节), 用于丙酮中的10分钟, 以去除派瑞林层。</li>
		<li>自旋涂层的微气泡基板与100µL 1% 飞碟 PVDMA 在无水氯仿在 1500 rpm 十五年代。</li>
		<li>在真空下将聚合物薄膜退火110摄氏度, 18 小时。</li>
		<li>油脂实验在丙酮或氯仿中的基质, 以10分钟去除表面上背景区域中的 physisorbed 聚合物。</li>
		<li>将基板存储在真空干燥中, 直到进一步使用。</li>
	</ol>
</li>
</ol>5. 定制飞碟-PVDMA 微接触印刷 (μCP)
<ol><li>制造<ol>
<li>根据标准的光刻工艺30制造硅大师。使用 CVD 工艺 (4.1.2 节) 将防粘 TPS 放到硅母版上。 注: 硅模具首次使用时应使用 TPS 处理, 并在使用5-10 次后重新应用。</li>
		<li>执行标准的软光刻方法制作邮票 (前体为固化剂质量比 10:1)31。 注: 本研究使用的邮票包括 micropillar 阵列 (直径 = 5-50 µm, 高度 = 20 µm)。</li>
		<li>剪掉一张邮票。在盐酸 (1 米), 丙酮5分钟内, 用乙醇 sonicating 10 分钟, 然后用5分钟来清洗。</li>
		<li>将在对流烤箱中的邮票干燥80摄氏度20分钟, 以去除残留的有机溶剂。</li>
	</ol>
</li>
	<li>微接触飞碟-硼PVDMA 在硅基板上的印刷<ol>
<li>使用 CVD 工艺 (4.1.2 节) 将 TPS 存入其表面。 注: TPS 层用于防止聚合物与图章表面的耦合。 注意: 在 TPS 吸附后, 接触角度测量可以用来表征邮票, 如图 2 (嵌入 A, B)所示。</li>
		<li>将飞碟-硼PVDMA 聚合物溶入无水氯仿中, 浓度为0.25-1%。</li>
		<li>将邮票浸入5毫升聚合物溶液中3分钟。</li>
		<li>等离子清洁 2×2 cm 裸硅基板3分钟清洁表面与飞碟块的耦合 (3.2 节)。</li>
		<li>从聚合物溶液中取出聚合物涂层的邮票。 注: 邮票必须用于打印, 而它们仍然是湿的, 并有一层的解决方案存在。</li>
		<li>在硅基板上直接放置墨印。</li>
		<li>使用手动钻床支架 (见材料表) (图 3) 将聚合物涂层的邮票按在硅表面上, 以促进图案的转移。在从聚合物溶液中取出包覆的邮票后, 立即将邮票应用于承印物 (1-2 秒以内)。 注: 在双面胶带的支持下, 无论是硅还是硅橡胶, 都可以将其放到最小, 以减少由于非均匀或高压冲压32而引起的双侧压印变形。</li>
		<li>在聚合物墨水和硅衬底之间应用保形接触1分钟. 使用估计压力75克/厘米2(7.35 帕) 按。</li>
		<li>轻轻地将邮票与硅表面隔开。</li>
		<li>在真空烤箱中立即将印刷的硅基板退火110摄氏度, 18 小时。</li>
		<li>油脂实验丙酮或氯仿中的印制硅基板, 以去除任何物理吸附的飞碟bPVDMA, 然后用 N2进行干燥。<ol>
<li>对超声波 (打印后的步骤) 和印制硅 (退火和步骤后) 进行表面特性分析, 以验证飞碟 PVDMA 的成功转移. 注: 表面轮廓和衰减的总反射率傅里叶变换红外光谱 (ATR-FTIR) 分析可以用来分析印刷硅基板和单片, 分别。</li>
		</ol>
</li>
		<li>将基底置于真空中, 干燥, 直到表征。</li>
	</ol>
</li>
</ol><img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57562/57562fig2.jpg"> 图 2: 用 ATR-红外光谱测量法处理过的聚硅烷 (相对强度).(嵌入 A)接触角度测量裸的。(嵌入 B)TPS 处理后的接触角测量。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57562/57562fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57562/57562fig3.jpg"> 图 3: 在硅基板上μCP 飞碟-b-PVDMA 溶液的设置.该程序包括使用(a)手动钻床, (B)一个 TPS 功能的飞碟 PVDMA 聚合物涂层, (C)等离子清洗2×2 cm 硅基板, (D)双面胶带。

作者没有什么可透露的。

本文提出了三种模式飞碟 PVDMA 的方法, 每个都有其优点和缺点。派瑞林升力法是一种通用的方法, 用于图形块共聚合体在微到纳米尺度的分辨率, 并已作为一个沉积面具在其他模式系统33,34,35。由于其表面附着力相对较弱, 在聚合物涂层后的溶剂中超声波可以很容易地从表面上去除派瑞林模具, 从而暴露出背景区域。背景区域似乎始终如一地清洁和无残留聚合物。由于派瑞林是惰性的到不同的表面36,37这种方法是有用的沉积飞碟-bPVDMA 到各种不同的背景表面化学。影响薄膜均匀性的一个因素是派瑞林钢板厚度。采用两种不同的派瑞林厚度 (1 µm 和 80 nm) (方法 A, 图 4)研究了钢板厚度对生成的飞碟-b-PVDMA 结构的影响。与1µm 相比, 80 nm 厚派瑞林的聚合物薄膜具有更高的均匀性, 但是, 在两种情况下, 在每个聚合物点周围都观察到边缘缺陷(图 5C, 5D)。这很可能是由于在自旋涂层过程中聚合物对模具的积聚, 然后在退火步骤中, 在图案边上交联成较厚的薄膜。然而, 退火对获得稳定的聚合物模式(图 5A, 5B)是至关重要的, 因此这种方法不可避免地会产生边缘缺陷。
作为一种替代方案, IDA 模式方法使用派瑞林模具生成氧化物模式, 以引导飞碟 PVDMA 聚合物自组装到无掩模沉积过程中的表面(方法 b, 图 4)。在有机溶剂中, 在自旋涂层步骤被超声波去除后, Physisorbed 聚合物在背景区域内立即出现。在执行这些步骤之后, brightfield、SEM 和 AFM 图像的表面显示出与氧化硅图案相匹配的飞碟-b PVDMA 模式(图 6A)。与以前的方法相比, 有图案的薄膜表现出高均匀性, 没有边缘缺陷, 因为在自旋涂层步骤中没有面具存在。所得到的聚合物薄膜的厚度是 90-100 nm, 与报告的厚度为飞碟-b-PVDMA 聚合物的刷子, 这个分子量20。这一优良特性通过调整飞碟-b-PVDMA 模式密度或 PVDMA 链的分子量, 使化学反应的精确操作得以实现。
尽管 IDA 方法在胶片均匀性很重要的应用中比较可取, 但该方法有两个固有的缺点。首先, 在背景区域内形成残留飞碟-b-PVDMA 聚合物, 在图 6A的 TPS 背景区域可以看到。如果背景聚合物是一个问题, 首先应检查背景的化学完整性与 ATR 红外或水接触角测量39。另外的超声波也可能有助于去除残余聚合物。第二, IDA 方法仅限于不活跃飞碟或 PVDMA 组的背景。其他含有反应性基团 (胺、硫醇等) 的背景可能会对聚合物进行耦合, 从而危及模式的完整性。
为了补充派瑞林和 IDA 模式方法, 自定义的µCP 协议生成更厚的飞碟bPVDMA 结构(方法 C, 图 4), 提供更高的表面到体积比, 这可能会提高加载在捕获应用中的化学或生物分析, 或改善细胞培养应用41,42的活性和增殖。在这种情况下, 表面化学的邮票和基体是必不可少的, 以保持有效的聚合物转移, 同时保持较高的模式完整性。飞碟-PVDMA 转移是促进通过处理邮票与 TPS 层, 以减少表面自由能的邮票44, 同时也处理硅基体与氧气血浆在打印之前立刻提供反应飞碟块23中存在的与环氧基团耦合的表面羟基基团。
µCP 协议的主要挑战来自于使用氯仿溶剂来制备聚合物墨量溶液。快速溶剂蒸发横跨邮票可能导致不均匀的聚合物墨量, 妥协模式再现性24,43。为了避免这种情况, 重要的是, 邮票被完全淹没在5毫升的墨量解决方案卷, 而不是吹打的解决方案在邮票表面上的小卷。对不同的浸没时间进行了研究, 发现3分钟对该过程是最佳的。在从解决方案中删除1-2 秒后, 必须将湿图章直接放在基板的顶部, 并使用 Dremel 工具设置将手动压力添加到图章上 (图 3)。这一过程允许在潮湿条件下进行转移, 这对于保持转移效率和一致性至关重要。如果从这个过程中的模式仍然显得不均匀, 邮票变形很可能。在这种情况下, 在软光刻步骤中, 可改变基/固化剂的比例, 以产生更硬的邮票46。
总之, 这里介绍的方法和结果描述了用飞碟-b-PVDMA 聚合物创建图案界面的多种方法。这些方法可用于产生有刷或交联结构的有图案的薄膜, 具体取决于应用。聚合物可以在化学或生物惰性的背景下进行图案。由于聚合物的沉积是沉积过程的最后一步, 所以在每个模式协议中都保留了 azlactone 功能。在模式之后, 基板可以用于后功能化与其他化学或生物组。

开发制造技术, 允许对化学和生物表面功能进行广泛和精确的控制, 对于各种应用, 从捕捉环境污染物到下一代的发展都是可取的。生物传感器, 植入物和组织工程设备1,2。功能高分子是通过 "嫁接" 或 "嫁接到" 技术3来调节表面性能的优良材料。这些方法允许控制的表面反应性的基础上的化学功能的单体和分子量的聚合物4,5,6。Azlactone 聚合物在这一背景下受到了强烈的研究, 因为 Azlactone 组在开环反应中有不同亲核试剂的快速耦合。这包括主要胺, 醇, 硫醇和肼组, 从而提供了一个多功能的路线进一步表面功能化7,8。Azlactone 聚合物薄膜已被应用于不同的环境和生物应用, 包括分析物捕获9,10, 细胞培养6,11, 和防污/防粘涂料12。在许多生物应用中, azlactone 聚合物薄膜在纳米到千分尺长度尺度上是可取的, 有利于空间控制分子呈现, 细胞相互作用, 或调节表面相互作用13, 14,15,16,17,18。因此, 应开发制造方法, 以提供高模式均匀性和良好的控制膜厚度, 而不损害化学功能19。
最近, Lokitz 开发了一种飞碟-b-PVDMA 嵌段共聚物, 能够操纵表面反应性。飞碟块对氧化-轴承表面, 产生高和可调谐的表面密度的 azlactone 组20。以前报告的模式, 这种聚合物的创建 biofunctional 接口使用传统的自上而下的光刻方法, 产生的非均匀聚合物薄膜的背景区域污染残留光刻胶材料, 造成高水平的非特异性化学和生物相互作用21、22、23。在这里, 试图钝化背景区域引起交叉反应与 azlactone 组, 损害聚合物反应性。考虑到这些限制, 我们最近开发了用于图案刷 (~ 90 nm) 或高度交联 (~ 1-10 微米) 的飞碟-PVDMA 薄膜的技术, 使其在化学或生物惰性的背景下完全保留化学聚合物的功能24。这些方法利用派瑞林升降、接口定向组装 (IDA) 和自定义微接触打印 (μCP) 技术。本文以书面和视频格式介绍了这些模式方法的高度详细的实验方法, 以及与每种技术相关的关键胶片特征和挑战和限制。

<table><tbody><tr><td>&lt;strong&gt;Material&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Ethanol, &amp;ge; 99.5%</td><td>Sigma-Aldrich</td><td>459844</td><td>-</td></tr><tr><td>HCL, 1.019 N in H2O</td><td>Fluka Analytical</td><td>318949</td><td>-</td></tr><tr><td>Acetone, &amp;ge; 99.5%</td><td>Sigma-Aldrich</td><td>320110</td><td>-</td></tr><tr><td>Benzene, &amp;ge; 99.9%</td><td>Sigma-Aldrich</td><td>270709</td><td>-</td></tr><tr><td>Isopropanol, ACS reagent, &amp;ge;99.5%</td><td>Sigma-Aldrich</td><td>190764</td><td></td></tr><tr><td>Hexane</td><td>Fisher Chemical</td><td>H292-4</td><td>-</td></tr><tr><td>Argon</td><td>Matheson Gas</td><td>G1901175</td><td>-</td></tr><tr><td>Tetrahydrofuran (THF), &amp;ge; 99.9%</td><td>Sigma-Aldrich</td><td>401757</td><td>-</td></tr><tr><td>Pluronic F-127</td><td>Sigma-Aldrich</td><td>P2443</td><td>-</td></tr><tr><td>Polydimethyl Siloxane (PDMS) Slygard 184</td><td>Dow Corning</td><td>4019862</td><td>-</td></tr><tr><td>Trichloro (1H,1H,2H,2H-perfluorooctyl) silane (TPS), 97%</td><td>Sigma-Aldrich</td><td>448931</td><td>It is toxic. Work with it under hood</td></tr><tr><td>Anhydrous Chloroform, &amp;ge; 99%</td><td>Sigma-Aldrich</td><td>372978</td><td>-</td></tr><tr><td>Positive Photoresist AZ1512</td><td>MicroChemicals</td><td>AZ 1512</td><td>amber-red liquid, density 1.083 g/cm3, spin coating step should be done under the hood</td></tr><tr><td>Developer AZ 300 MIF</td><td>MicroChemicals</td><td>AZ300 MIF</td><td>clear colourless liquid with slight amine odor and density of 1 g/cm3</td></tr><tr><td>1,2-Vinyl-4,4- dimethyl azlactone (VDMA)</td><td>Isochem North America, LLC</td><td>VDMA</td><td>-</td></tr><tr><td>2-cyano-2-propyl dodecyl trithiocarbonate (CPDT)</td><td>Sigma-Aldrich</td><td>723037</td><td>-</td></tr><tr><td>2,2&amp;prime;-Azobis (4methoxy-2,4-dimethyl valeronitrile) (V-70)</td><td>Wako Specialty Chemicals</td><td>CAS NO. 15545-97-8, EINECS No. 239-593-8</td><td>-</td></tr><tr><td>Parylene N</td><td>Specialty Coating Systems</td><td>15B10004</td><td>-</td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Parylene Coater</td><td>Specialty Coating Systems</td><td>SCS Labcoater (PDS 2010)</td><td>-</td></tr><tr><td>Mask alignment system</td><td>Neutronix Quintel</td><td>NXQ8000</td><td>-</td></tr><tr><td>Oxygen Plasma Etcher</td><td>Oxford Instruments</td><td>Plasma Lab System 100</td><td>-</td></tr><tr><td>Surface Profilometer</td><td>Veeco</td><td>Dektak 150</td><td>Scan type was standard hill. Scan duration and force were 120 s and 1 mg, respectively.</td></tr><tr><td>Brightfield Upright Microscope</td><td>Olympus Corporation</td><td>BX51</td><td>-</td></tr><tr><td>Oxygen Plasma&amp;nbsp; Cleaner</td><td>Harrick Plasma</td><td>PDC-001-HP</td><td>-</td></tr><tr><td>Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR)</td><td>Perkin Elmer</td><td>ATR-FTIR 100</td><td>-</td></tr><tr><td>Atomic Force Microscopy (AFM)</td><td>PicoPlus</td><td>Picoplus atomic force microscope</td><td>Veeco MLCT-E cantilevers with a 0.5 N/m spring constant. Scan speeds varied between 0.25 and 1 Hz.</td></tr><tr><td>Scanning Electron Microscopy (SEM)</td><td>Hitachi Science Systems Ltd., Tokyo, Japan</td><td>-</td><td>-</td></tr><tr><td>Rotary Tool Workstation</td><td>Dremel</td><td>Model 220-01</td><td>-</td></tr><tr><td>Spin Coater</td><td>Smart Coater</td><td>SC100</td><td>-</td></tr><tr><td>Vacuum Oven</td><td>Yamato Scientific Co.</td><td>PCD-C6(5)000)</td><td>-</td></tr><tr><td>Size Exclusion Chromatography (SEC)</td><td>Waters Alliance 2695 Separations Module</td><td>720004547EN</td><td>-</td></tr><tr><td>Refractive Index (RI) detector</td><td>Waters</td><td>Model 2414</td><td>-</td></tr><tr><td>Photodiode Array Detector</td><td>Waters</td><td>Model 2996, 716001286</td><td>-</td></tr><tr><td>Multi-angle Light Scattering (MALS) Detector</td><td>Wyatt Technology</td><td>miniDAWN TREOS II</td><td>-</td></tr><tr><td>Viscometer</td><td>Wyatt Technology</td><td>Viscostar</td><td>-</td></tr><tr><td>PLgel 5 &amp;micro;m mixed-C columns (300 x 7.5 mm)</td><td>Agilent</td><td>5 &amp;micro;m mixed-C columns</td><td>-</td></tr><tr><td>Ellipsometer</td><td>J. A. Woollam</td><td>alpha-SE</td><td>Cauchy model, PGMA and PVDMA layers had refractive indices of 1.50 and 1.52 at 632 nm</td></tr><tr><td>Ultrasonic Sonicator</td><td>Fischer Scientific</td><td>FS-110H</td><td>-</td></tr></tbody></table>

fabricating reactive surfaces with brush-like and crosslinked films of azlactone-functionalized block co-polymers

本文介绍了利用 azlactone 基块共聚合物、聚 (甲基丙烯酸缩水甘油)-块状聚 (乙烯二甲基 azlactone) (飞碟bPVDMA) 生成新表面的制备方法。由于 azlactone 基团对胺、硫醇和羟基基团的高反应性, 飞碟-bPVDMA 表面可以通过二次分子进行修饰, 从而为各种应用创造化学或生物功能化界面。以前的飞碟-b-PVDMA 界面的报告使用了传统的自上而下的模式技术, 产生不均匀的薄膜和控制不善的背景化学。在这里, 我们描述了定制的模式技术, 使高均匀的飞碟bPVDMA 薄膜在化学惰性或具有分子的性质的背景下精确沉积。重要的是, 这些方法旨在以一种完全保留 azlactone 功能的方式, 通过每个处理步骤来存放飞碟-bPVDMA 薄膜。图案化的薄膜显示了与聚合物刷子 (90 nm) 或高度交联结构 (~ 1-10 微米) 相对应的良好控制厚度。画笔图案是使用派瑞林升力或接口定向装配方法生成的, 它对于通过调整飞碟-bPVDMA 模式密度或VDMA 块的长度。相比之下, 厚, 交联的飞碟-PVDMA 模式是通过定制的微接触印刷技术, 并提供了较高的加载或捕获二次材料由于较高的表面积, 体积比。讨论了各制造方法的详细实验步骤、关键胶片特征和故障排除指南。

接触角测量可用于评价硅与飞碟-PVDMA 的功能化。图 1描述了不同加工步骤中硅基板的接触角。等离子清洗硅基板的亲水性行为如图 1B所示。聚合物自旋涂层和退火后的接触角是 75° 1°(图 1C) , 它与 Lokitz等PVDMA 表面20所报告的值一致。
图 2显示了µCP 过程的不同步骤中的 ATR-FTIR 光谱和接触角的测量。印刷后, azlactone 羰基拉伸振动在〜1818厘米-1下降 34 9%。图 2(嵌入 A, B)还描述了在 TPS 处理后, 对其疏水性的变化。
邮票衬底冲压是µCP 的关键步骤.图 3展示了手动旋转工具的不同部分, 以实现聚合物涂层邮票和硅基板之间的均匀接触。
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57562/57562fig4.jpg"> 图 4: 已开发的用于将飞碟 PVDMA 成图案化、交联或刷膜的技术的详细信息。这个数字已经从 Masigol等。24 .(A)在硅基板上绘制聚合物刷子的派瑞林升降协议的示意图表示法, 1.硅片 (w/本机氧化物), 2.派瑞林沉积 (1 µm 或 80 nm), 3.光刻胶自旋涂层, 4.紫外线照射和发展, 5.氧气等离子蚀刻, 6.聚合物自旋涂层, 7.退火和派瑞林的升降。(B) IDA 在生物/化学 (PEG/TPS) 惰性基底上绘制聚合物刷子的程序, 1.硅片 (w/本机氧化物), 2.PEG/TPS 沉积, 3.派瑞林沉积 (1 µm 或 80 nm), 4.光刻胶自旋涂层, 5.紫外线曝光和发展, 6.氧气等离子治疗, 7.派瑞林升降, 8.聚合物自旋涂层, 9.退火和超声波。(C)使用µCP 方法, 在硅上生成交联聚合物结构, 1.用软光刻法制作的塑料印花, 其次是 tps 涂层, 2. tps 功能的聚合物油墨3.邮票/承印物接触, 4.退火和超声波。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57562/57562fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
图 4显示了生成聚合物模式24的分步过程。这些程序的目的是: (1) 飞碟-硼PVDMA 聚合物的模式均匀刷结构在化学/生物惰性基底上应用派瑞林的推力和 IDA 技术(图 4A, 4B), 或 (2) 产生较厚的微米级厚度薄膜模式(图 4C).
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/57562/57562fig5.jpg"> 图 5: 派瑞林升降程序的代表性结果.(A) Brightfield 在硅上的飞碟-b-PVDMA 聚合物模式的图像, 退火(嵌入 i)和不退火(插入 ii) (鳞片棒 = 40 µm)。(B)用或不退火法测定氯仿10分钟超声波后的聚合物厚度。(C) 1 µm 厚派瑞林模具的截面聚合物高度剖面。(D) 80 nm 厚派瑞林模具的截面聚合物高度剖面。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57562/57562fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
派瑞林技术可用于实现飞碟-硼PVDMA 块共聚合体的刷结构, 对应于90纳米薄膜厚度。图 5A (插入 i)描述被无聚合物背景包围的图案斑点。退火是通过环氧基团在24表面氧化物上的反应对聚合物相分离和强共价表面附着的关键步骤。如图 5A (插入 ii)所示, 如果不进行退火, 氯仿中的超声波将会去除许多有图案的聚合物。为了更详细地研究退火的效果, 1%. 氯仿中聚合物的浓度在等离子清洗硅基板上 (无派瑞林) 进行了旋涂。用椭偏法测量聚合物厚度 (见材料表)。虽然超声波在氯仿导致大部分的聚合物从非退火基板, 没有显着的变化, 聚合物的厚度被观察退火基体(图 5B)。与1µm 派瑞林钢板蜡纸相比, 80 毫微米派瑞林钢板蜡纸产生更高的薄膜均匀性(图 5C, 5D)。
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/57562/57562fig6.jpg"> 图 6: IDA 方法在化学和生物惰性背景下产生飞碟-PVDMA 的类似画笔模式的代表性结果。这个数字已经从 Masigol等。24 .(A) TPS 和PEG 背景下的飞碟-PVDMA 模式。(B) AFM 在 TPS 涂层基体上测量聚合物形态和代表性聚合物膜厚度。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57562/57562fig6large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
在化学或生物惰性背景下, IDA 技术可用于飞碟-硼PVDMA 聚合物的均匀膜的共模。图 6A显示了飞碟-PVDMA 模式在 PEG/TPS 背景。这种方法的结果是 90-100 nm 厚度的图案薄膜, 没有从先前的方法观察到的边缘缺陷(图 5C, 5D).图 6B中的 AFM 剖面描述了使用 IDA 方法获得的聚合物膜厚度。
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/57562/57562fig7.jpg"> 图 7: 飞碟 PVDMA 交联膜μCP 技术的代表性结果.这个数字已经从 Masigol等。24. (A)印在硅基板上的聚合物的高度剖面(1% 的聚合物)。(插入 i)飞碟-b-PVDMA 模式获得后, µCP 与退火, (插入 ii)没有退火 (鳞片杆 = 30 µm)。(b)飞碟-PVDMA 印刷后裸硅和硅基板的 ATR-FTIR 分析。(C)使用不同的聚合物墨量浓度对平均交联膜高度的影响 (误差条描述标准偏差从平均值)。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57562/57562fig7large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
µCP 是在硅表面上形成飞碟-硼PVDMA 聚合物的最终方法。与派瑞林和 IDA 技术相比, 这种方法的结果是在微米级厚度的聚合物薄膜(图 7A)。在印刷过程中, 有几个关键步骤需要确保有效地将聚合物从邮票上转移到基体上。首先, 需要使用 TPS 进行功能化, 以抑制飞碟PVDMA 与图章的耦合(图 2, 嵌入 A, b)。其次, 需要在基体上进行等离子处理, 形成氧化物表面层, 与聚合物飞碟块中存在的环氧基团(图 1B)进行反应。最后, 需要对冲压聚合物薄膜进行退火, 以促进整个薄膜的交联;图 7A (嵌入 i 和 ii)显示退火和非退火基板后, 超声波, 其中对非退火膜的严重损害观察。对图案技术的另一个要求是保留 azlactone 功能, 通过测量羰基拉伸振动的1818厘米-1 (图 7B)来验证这一点。最后, µCP 技术还通过在飞碟中改变了氯仿的浓度, 使聚合物厚度薄膜的微尺度控制(图 7C)。

Watch this Scientific Journal Video about Fabricating Reactive Surfaces with Brush-like and Crosslinked Films of Azlactone-Functionalized Block Co-Polymers at JoVE.com

Fabricating Reactive Surfaces with Brush-like and Crosslinked Films of Azlactone-Functionalized Block Co-Polymers

报道了 azlactone 块共聚合物纳米厚刷或微米厚、交联膜的表面制备方法。讨论了关键的实验步骤、代表性结果和每个方法的局限性。这些方法对于创建具有定制物理特性和可调谐表面反应性的功能接口非常有用。

Azlactone 功能块共聚物的刷状和交联膜制备反应表面

In this paper, fabrication methods that generate novel surfaces using the azlactone-based block co-polymer, poly (glycidyl methacrylate)-block-poly (vinyl ...

fabricating-reactive-surfaces-with-brush-like-crosslinked-films

Nanyang Technological University

Research

JoVE Journal

Engineering

8.2K 次观看.  Kansas State University. 报道了 azlactone 块共聚合物纳米厚刷或微米厚、交联膜的表面制备方法。讨论了关键的实验步骤、代表性结果和每个方法的局限性。这些方法对于创建具有定制物理特性和可调谐表面反应性的功能接口非常有用。

视频: Fabricating Reactive Surfaces with Brush-like and Crosslinked Films of Azlactone-Functionalized Block Co-Polymers

Using Polystyrene-block-poly(acrylic acid)-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are encapsulated in polystyrene-block-poly(acrylic acid) (PSPAA) shells and then used as monomers for their self-assembly. Spherical PSPAA micelles upon acid treatment are known to assemble into cylindrical micelles. Exploiting this tendency, the core-shell nanoparticles are induced to aggregate, coalesce, and then transform into long chains. When more than one type of nanoparticles are used, random and block &#8220;copolymers&#8221; of nanoparticles can be obtained. Detailed procedures are reported for the PSPAA encapsulation of nanoparticles, homo- and co-polymerization of the core-shell nanoparticles, separation and purification of the resulting nanoparticle chains. Transformations of single-line chains into double- and triple-line chains are also presented. The synergy between the polymer shell and the embedded nanoparticles leads to an unusual chain-growth polymerization mode, giving long nanoparticle chains that are distinct from the products of the traditional step-growth aggregation process.

Using Polystyrene-block-polyacrylic acid-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We report protocols for &#8220;polymerizing&#8221; various types of polymer-encapsulated metal nanoparticles into long chains of &#8220;homo-&#8220; and &#8220;co-polymers&#8221;.

使用聚苯乙烯<em&gt;块</em&gt; - 聚（丙烯酸）涂层的金属纳米颗粒作为单体他们均聚物和共聚物聚合

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are ...

科研

化学

High-throughput Synthesis of Carbohydrates and Functionalization of Polyanhydride Nanoparticles

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design efficacious vaccines carriers. Nanoparticle-based platforms can prolong the persistence of vaccine antigens, which could improve vaccine immunogenicity1. Several biodegradable polymers have been studied as vaccine delivery vehicles1; in particular, polyanhydride particles have demonstrated the ability to provide sustained release of stable protein antigens and to activate antigen presenting cells and modulate immune responses2-12.
The molecular design of these vaccine carriers needs to integrate the rational selection of polymer properties as well as the incorporation of appropriate targeting agents. High throughput automated fabrication of targeting ligands and functionalized particles is a powerful tool that will enhance the ability to study a wide range of properties and will lead to the design of reproducible vaccine delivery devices.
The addition of targeting ligands capable of being recognized by specific receptors on immune cells has been shown to modulate and tailor immune responses10,11,13 C-type lectin receptors (CLRs) are pattern recognition receptors (PRRs) that recognize carbohydrates present on the surface of pathogens. The stimulation of immune cells via CLRs allows for enhanced internalization of antigen and subsequent presentation for further T cell activation14,15. Therefore, carbohydrate molecules play an important role in the study of immune responses; however, the use of these biomolecules often suffers from the lack of availability of structurally well-defined and pure carbohydrates. An automation platform based on iterative solution-phase reactions can enable rapid and controlled synthesis of these synthetically challenging molecules using significantly lower building block quantities than traditional solid-phase methods16,17.
Herein we report a protocol for the automated solution-phase synthesis of oligosaccharides such as mannose-based targeting ligands with fluorous solid-phase extraction for intermediate purification. After development of automated methods to make the carbohydrate-based targeting agent, we describe methods for their attachment on the surface of polyanhydride nanoparticles employing an automated robotic set up operated by LabVIEW as previously described10. Surface functionalization with carbohydrates has shown efficacy in targeting CLRs10,11 and increasing the throughput of the fabrication method to unearth the complexities associated with a multi-parametric system will be of great value (Figure 1a).

In this article, a high throughput method is presented for the synthesis of oligosaccharides and their attachment to the surface of polyanhydride nanoparticles for further use in targeting specific receptors on antigen presenting cells.

碳水化合物和聚酸酐纳米粒子功能化的高通量合成

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design ...

生物工程

Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline elastomers (LCEs) with facile control over network structure and programming of an aligned monodomain. Tailored LCE networks were synthesized using routine mixing of commercially available starting materials and pouring monomer solutions into molds to cure. An initial polydomain LCE network is formed via a self-limiting thiol-acrylate Michael-addition reaction. Strain-to-failure and glass transition behavior were investigated as a function of crosslinking monomer, pentaerythritol tetrakis(3-mercaptopropionate) (PETMP). An example non-stoichiometric system of 15 mol% PETMP thiol groups and an excess of 15 mol% acrylate groups was used to demonstrate the robust nature of the material. The LCE formed an aligned and transparent monodomain when stretched, with a maximum failure strain over 600%. Stretched LCE samples were able to demonstrate both stress-driven thermal actuation when held under a constant bias stress or the shape-memory effect when stretched and unloaded. A permanently programmed monodomain was achieved via a second-stage photopolymerization reaction of the excess acrylate groups when the sample was in the stretched state. LCE samples were photo-cured and programmed at 100%, 200%, 300%, and 400% strain, with all samples demonstrating over 90% shape fixity when unloaded. The magnitude of total stress-free actuation increased from 35% to 115% with increased programming strain. Overall, the two-stage TAMAP methodology is presented as a powerful tool to prepare main-chain LCE systems and explore structure-property-performance relationships in these fascinating stimuli-sensitive materials.

A novel methodology is presented to synthesize and program main-chain liquid-crystalline elastomers using commercially available starting monomers. A wide range of thermomechanical properties was tailored by adjusting the amount of crosslinker, while the actuation performance was dependent on the amount of applied strain during programming.

的可编程主链液晶性弹性体用双级硫醇丙烯酸酯反应合成

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline ...

Functionalization of Single-walled Carbon Nanotubes with Thermo-reversible Block Copolymers and Characterization by Small-angle Neutron Scattering

We demonstrate a protocol for single-walled carbon nanotube functionalization using thermo-sensitive PEO-PPO-PEO triblock copolymers in an aqueous solution. In a carbon nanotube/PEO105-PPO70-PEO105 (poloxamer 407) aqueous solution, the amphiphilic poloxamer 407 adsorbs onto the carbon nanotube surfaces and self-assembles into continuous layers, driven by intermolecular interactions between constituent molecules. The addition of 5-methylsalicylic acid changes the self-assembled structure from spherical-micellar to a cylindrical morphology. The fabricated poloxamer 407/carbon nanotube hybrid particles exhibit thermo-responsive structural features so that the density and thickness of poloxamer 407 layers are also reversibly controllable by varying temperature. The detailed structural properties of the poloxamer 407/carbon nanotube particles in suspension can be characterized by small-angle neutron scattering experiments and model fit analyses. The distinct curve shapes of the scattering intensities depending on temperature control or addition of aromatic additives are well described by a modified core-shell cylinder model consisting of a carbon nanotube core cylinder, a hydrophobic shell, and a hydrated polymer layer. This method can provide a simple but efficient way for the fabrication and in-situ characterization of carbon nanotube-based nano particles with a structure-tunable encapsulation.

A method for the functionalization of carbon nanotubes with structure-tunable polymeric encapsulation layers and structural characterization using small-angle neutron scattering is presented.

单壁碳纳米管与热可逆嵌段共聚物及表征功能化小角度中子散射

We demonstrate a protocol for single-walled carbon nanotube functionalization using thermo-sensitive PEO-PPO-PEO triblock copolymers in an aqueous ...

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

使用Photoredox催化剂蠕虫状胶束的简便合成可见光介导的分散聚合

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

Methionine Functionalized Biocompatible Block Copolymers for Targeted Plasmid DNA Delivery

Reversible addition-fragmentation chain transfer (RAFT) polymerization integrates the advantages of radical polymerization and living polymerization. This work presents the preparation of methionine functionalized biocompatible block copolymers via RAFT polymerization. Firstly, N,N-bis(2-hydroxyethyl)methacrylamide-b-N-(3-aminopropyl)methacrylamide (BNHEMA-b-APMA, BA) was synthesized via RAFT polymerization using 4,4&#8217;-azobis(4-cyanovaleric acid) (ACVA) as an initiating agent and 4-cyanopentanoic acid dithiobenzoate (CTP) as the chain transfer agent. Subsequently, N,N-bis(2-hydroxyethyl)methacrylamide-b-N-(3-guanidinopropyl)methacrylamide (methionine grafted BNHEMA-b-GPMA, mBG) was prepared by modifying amine groups in APMA with methionine and guanidine groups. Three kinds of block polymers, mBG1, mBG2, and mBG3, were synthesized for comparison. A ninhydrin reaction was used to quantify the APMA content; mBG1, mBG2, and mBG3 had 21%, 37%, and 52% of APMA, respectively. Gel permeation chromatography (GPC) results showed that BA copolymers possess molecular weights of 16,200 (BA1), 20,900(BA2), and 27,200(BA3) g/mol. The plasmid DNA (pDNA) complexing ability of the obtained block copolymer gene carriers was also investigated. The charge ratios (N/P) were 8, 16, and 4 when pDNA was complexed completely with mBG1, mBG2, mBG3, respectively. When the N/P ratio of mBG/pDNA polyplexes was higher than 1, the Zeta potential of mBG was positive. At an N/P ratio between 16 and 32, the average particle size of mBG/pDNA polyplexes was between 100-200 nm. Overall, this work illustrates a simple and convenient protocol for the block copolymer carrier synthesis.

This work presents the preparation of methionine functionalized biocompatible block copolymers (mBG) via the reversible addition-fragmentation chain transfer (RAFT) method. The plasmid DNA complexing ability of the obtained mBG and their transfection efficiency were also investigated. The RAFT method is very beneficial for polymerizing monomers containing special functional groups.

用于靶向质粒DNA输送的美聚氨酸功能化生物相容性块共聚物

Reversible addition-fragmentation chain transfer (RAFT) polymerization integrates the advantages of radical polymerization and living polymerization. This ...

Preparation of Poly(pentafluorophenyl acrylate) Functionalized SiO2 Beads for Protein Purification

We demonstrate a simple method to prepare poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads for antibody immobilization and subsequent immunoprecipitation (IP) application. The poly(PFPA) grafted surface is prepared via a simple two-step process. In the first step, 3-aminopropyltrimethoxysilane (APTMS) is deposited as a linker molecule onto the silica surface. In the second step, poly(PFPA) homopolymer, synthesized via the reversible addition and fragmentation chain transfer (RAFT) polymerization, is grafted to the linker molecule through the exchange reaction between the pentafluorophenyl (PFP) units on the polymer and the amine groups on APTMS. The deposition of APTMS and poly(PFPA) on the silica particles are confirmed by X-ray photoelectron spectroscopy (XPS), as well as monitored by the particle size change measured via dynamic light scattering (DLS). To improve the surface hydrophilicity of the beads, partial substitution of poly(PFPA) with amine-functionalized poly(ethylene glycol) (amino-PEG) is also performed. The PEG-substituted poly(PFPA) grafted silica beads are then immobilized with antibodies for IP application. For demonstration, an antibody against protein kinase RNA-activated (PKR) is employed, and IP efficiency is determined by Western blotting. The analysis results show that the antibody immobilized beads can indeed be used to enrich PKR while non-specific protein interactions are minimal.

Preparation of Polypentafluorophenyl acrylate Functionalized SiO2 Beads for Protein Purification

A protocol for the preparation of poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads is presented. The poly(PFPA) functionalized surface is then immobilized with antibodies and used successfully for the protein separation through immunoprecipitation.

聚五氟丙烯酸酯 (五氟丙烯酸酯) 功能化 sio2 珠的蛋白质纯化

We demonstrate a simple method to prepare poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads for antibody immobilization and subsequent ...

Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock copolymers are produced by one of three techniques: thin film rehydration, solvent switching or polymerization-induced self-assembly, and produce only flexible, polydisperse cylinders. Crystallization-driven self-assembly (CDSA) is a method which can produce cylinders with these properties, by stabilizing structures of a lower curvature due to the formation of a crystalline core. However, the living polymerization techniques by which most core-forming blocks are formed are not trivial processes and the CDSA process may yield unsatisfactory results if carried out incorrectly. Here, the synthesis of cylindrical nanoparticles from simple reagents is shown. The drying and purification of reagents prior to a ring-opening polymerization of &#949;-caprolactone catalyzed by diphenyl phosphate is described. This polymer is then chain extended by methyl methacrylate (MMA) followed by N,N-dimethyl acrylamide (DMA) using reversible addition&#8722;fragmentation chain-transfer (RAFT) polymerization, affording a triblock copolymer that can undergo CDSA in ethanol. The living CDSA process is outlined, the results of which yield cylindrical nanoparticles up to 500 nm in length and a length dispersity as low as 1.05. It is anticipated that these protocols will allow others to produce cylindrical nanostructures and elevate the field of CDSA in the future.

Crystallization-driven self-assembly (CDSA) displays the unique ability to fabricate cylindrical nanostructures of narrow length distributions. The organocatalyzed ring-opening polymerization of &#949;-caprolactone and subsequent chain extensions of methyl methacrylate and N,N-dimethyl acrylamide are demonstrated. A living CDSA protocol that produces monodisperse cylinders up to 500 nm in length is outlined.

通过结晶驱动生物降解块共聚物的自组装合成单分散圆柱状纳米粒子

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock ...

Preparation of Thermoresponsive Nanostructured Surfaces for Tissue Engineering

Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm)-immobilized surfaces for controlling cell adhesion and detachment were fabricated by the Langmuir-Schaefer method. Amphiphilic block copolymers composed of polystyrene and PIPAAm (St-IPAAms) were synthesized by reversible addition-fragmentation chain transfer (RAFT) radical polymerization. A chloroform solution of St-IPAAm molecules was gently dropped into a Langmuir-trough apparatus, and both barriers of the apparatus were moved horizontally to compress the film to regulate its density. Then, the St-IPAAm Langmuir film was horizontally transferred onto a hydrophobically modified glass substrate by a surface-fixed device. Atomic force microscopy images clearly revealed nanoscale sea-island structures on the surface. The strength, rate, and quality of cell adhesion and detachment on the prepared surface were modulated by changes in temperature across the lower critical solution temperature range of PIPAAm molecules. In addition, a two-dimensional cell structure (cell sheet) was successfully recovered on the optimized surfaces. These unique PIPAAm surfaces may be useful for controlling the strength of cell adhesion and detachment.

Nanoscaled sea-island surfaces composed of thermoresponsive block copolymers were fabricated by the Langmuir-Schaefer method for controlling spontaneous cell adhesion and detachment. Both the preparation of the surface and the adhesion and detachment of cells on the surface were visualized.

温敏纳米结构表面的组织工程准备

Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm)-immobilized surfaces for controlling cell adhesion and detachment were fabricated by the ...

The Synthesis of RGD-functionalized Hydrogels as a Tool for Therapeutic Applications

The use of polymers as biomaterials has provided significant advantages in therapeutic applications. In particular, the possibility to modify and functionalize polymer chains with compounds that are able to improve biocompatibility, mechanical properties, or cell viability allows the design of novel materials to meet new challenges in the biomedical field. With the polymer functionalization strategies, click chemistry is a powerful tool to improve cell-compatibility and drug delivery properties of polymeric devices. Similarly, the fundamental need of biomedicine to use sterile tools to avoid potential adverse-side effects, such as toxicity or contamination of the biological environment, gives rise to increasing interest in the microwave-assisted strategy.
The combination of click chemistry and the microwave-assisted method is suitable to produce biocompatible hydrogels with desired functionalities and improved performances in biomedical applications. This work aims to synthesize RGD-functionalized hydrogels. RGD (arginylglycylaspartic acid) is a tripeptide that can mimic cell adhesion proteins and bind to cell-surface receptors, creating a hospitable microenvironment for cells within the 3D polymeric network of the hydrogels. RGD functionalization occurs through Huisgen 1,3-dipolar cycloaddition. Some PAA carboxyl groups are modified with an alkyne moiety, whereas RGD is functionalized with azido acid as the terminal residue of the peptide sequence. Finally, both products are used in a copper catalyzed click reaction to permanently link the peptide to PAA. This modified polymer is used with carbomer, agarose and polyethylene glycol (PEG) to synthesize a hydrogel matrix. The 3D structure is formed due to an esterification reaction involving carboxyl groups from PAA and carbomer and hydroxyl groups from agarose and PEG through microwave-assisted polycondensation. The efficiency of the gelation mechanism ensures a high degree of RGD functionalization. In addition, the procedure to load therapeutic compounds or biological tools within this functionalized network is very simple and reproducible.

We present a protocol for the synthesis of RGD-functionalized hydrogels as devices for cell and drug delivery. The procedure involves copper catalyzed alkyne-azide cycloaddition (CuAAC) between alkyne-modified polyacrylic acid (PAA) and a RGD-azide derivative. The hydrogels are formed using microwave-assisted polycondensation and their physicochemical properties are investigated.

Azlactone 功能块共聚物的刷状和交联膜制备反应表面

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