Hydrogels - Soft Antifoulants ag

Hydrogels - Soft Antifoulants against Barnacles Hydro gel s - 针对藤壶的软质防污剂

Antifouling gel 防污凝胶

Index

1. Introduction介绍
2. Barnacles藤壶
3. Life cycle生命周期
4. Antifouling properties of hydrogels水凝胶的防污性能
5. Field application of antifouling materials防污材料的现场应用
6. References参考

Introduction

Marine biofouling is being taken into account recently with great importance. In brief, biofouling is defined as the undesirable accumulation of microorganisms, plants, algae, and/or animals on wetted structures.
最近正在考虑海洋生物污损非常重要。简而言之，生物污垢被定义为微生物，植物，藻类和/或动物在湿润结构上的不期望的积累。

Biofouling is divided into microfouling, which is the formation of biofilms and bacterial adhesion, and macrofouling, which is the attachment of larger organisms, of which the main culprits are barnacles, mussels, polychaete worms, bryozoans, and seaweed. Together, these organisms form a fouling community. Individually, small, accumulated biofoulers can form enormous masses that severely diminish the maneuverability and carrying capacity of ships, which could result in the reduction of vessel performance and consequently increase fuel requirements. Fouling leads to huge material and economic costs in the maintenance of mariculture, shipping industries, naval vessels, and seawater pipelines. Biofouling is also observed in almost all circumstances where water-based liquids are in contact with other materials. Industrially important examples include membrane systems, where membrane bioreactors and reverse osmosis spiral wound membranes are used to cool water cycles of large industrial equipment and power stations. The concept of antifouling has been developed to address the issue of biofouling. Antifouling is the process of removing or preventing the accumulation of microorganisms. In industrial processes, bio-dispersants can be used to control biofouling. In the past forty to fifty years, scientists have been working in search of an effective surface to be used as an antifoulant against barnacles. In this regard, most of the researchers worked with tributyltin moiety (TBT) and polydimethylsiloxane (PDMS) to discover effective anti-fouling agents. Although TBT was found to be an excellent antifouling agent, it is banned by the International Maritime Organization from 2008 because of its high endocrine-disruption effect.
生物污染分为微生物，即生物膜和细菌粘附的形成，以及大型生物的附着物，其中主要元凶是藤壶，贻贝，多毛虫，苔藓虫和海藻。这些生物一起形成了污垢社区。单独的，小的，积聚的生物污染物可形成巨大的质量，严重降低船舶的机动性和承载能力，这可能导致船舶性能的降低并因此增加燃料需求。污染导致维持海水养殖，航运业，海军舰艇和海水管道的巨大物质和经济成本。在水基液体与其他材料接触的几乎所有情况下也观察到生物污损。工业上重要的例子包括膜系统，其中膜生物反应器和反渗透螺旋缠绕膜用于冷却大型工业设备和发电站的水循环。已经开发出防污概念来解决生物污损问题。防污是去除或防止微生物积聚的过程。在工业过程中，生物分散剂可用于控制生物污损。在过去的四十到五十年里，科学家们一直致力于寻找一种有效的表面，用作防止藤壶的防污剂。在这方面，大多数研究人员使用三丁基锡部分（TBT）和聚二甲基硅氧烷（PDMS）来发现有效的防污剂。虽然TBT被认为是一种优良的防污剂，

These days, scientists are concentrating on the search for suitable materials as antifoulants, which will not only have an excellent capacity to inhibit biofouling, but will also be environmentally benign. Very few scientists have worked with hydrogels to establish them as effective and environmentally friendly materials to be used as antifouling agents. The main reason for choosing hydrogels as antifouling agents is its softness, which inhibits barnacles from settling on them because barnacles are usually found to settle on hard surfaces like wood, plastic, bamboo, glass, blue mussel shells, oyster shells, etc. Moreover, the hydrophilic nature of the hydrogels may be the key factor to render them excellent candidates against biofouling because the glycoproteinous substance in barnacle cement has the characteristic of hydrophobicity. Therefore, barnacles dislike settling on hydrogel surfaces. So far, in vitro as well as in vivo tests used to investigate the anti-fouling capacity of hydrogels against barnacles have been effective. Not only the settlement but also the growth of barnacles on hydrogels will be examined in the near future.
如今，科学家们正专注于寻找合适的材料作为防污剂，这不仅具有抑制生物污垢的优异能力，而且对环境无害。很少有科学家使用水凝胶将它们作为有效且环保的材料用作防污剂。选择水凝胶作为防污剂的主要原因是它的柔软性，可以抑制藤壶沉淀在它们上面，因为通常会发现藤壶固定在坚硬的表面上，如木头，塑料，竹子，玻璃，蓝贻贝壳，牡蛎壳等。此外，水凝胶的亲水性可能是使它们成为抗生物污损的优良候选物质的关键因素，因为藤壶水泥中的糖蛋白物质具有疏水性的特征。因此，藤壶不喜欢沉淀在水凝胶表面上。到目前为止，用于研究水凝胶对藤壶的防污能力的体外和体内试验都是有效的。不仅将在不久的将来检查沉降，还会研究水凝胶上藤壶的生长情况。

Barnacles 藤壶

A barnacle is a type of arthropod belonging to the infraclass Cirripedia in the subphylum Crustacea; hence, it is related to crabs and lobsters. Barnacles are exclusively marine and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders and have two nektonic larval stages. Barnacles are encrusters, attaching themselves permanently to a hard substrate. The most common, "acorn barnacles" (Sessilia) are sessile, with their shells growing directly onto the substrate. Members of the order Pedunculata ("goose barnacles" and others) attach themselves by means of a stalk.
藤壶是一种节肢动物，属于甲壳动物亚门中的鳞翅目Cirripedia; 因此，它与螃蟹和龙虾有关。藤壶只是海洋生物，往往生活在浅水和潮水中，通常在腐蚀性环境中。它们是无柄悬浮喂食器，有两个游泳幼虫阶段。藤壶是绷带，永久地附着在坚硬的基底上。最常见的“橡子藤壶”（Sessilia）是无柄的，它们的壳直接生长在基质上。Pedunculata（“鹅藤壶”等）的成员通过茎附着自己。

Although they have been found at water depths of up to 600 m (2,000 ft), most barnacles inhabit shallow waters, with 75% of all species living in water depths of less than 100 m (300 ft) and 25% inhabiting the intertidal zone. Within the intertidal zone, different species of barnacles live in very tightly constrained locations, allowing the exact height of an assemblage above or below sea level to be precisely determined.
虽然它们的水深高达600米（2,000英尺），但大多数藤壶栖息在浅水区，75％的物种生活在水深不到100米（300英尺），25％栖息在潮间带。 。在潮间带内，不同种类的藤壶生活在非常严格约束的位置，允许精确确定高于或低于海平面的组合的精确高度。

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Life cycle 生命周期

Barnacles have two distinct larval stages. In the first stage, a fertilized egg hatches into a nauplius, a one-eyed larva having a head and a telson, without a thorax or abdomen. It undergoes six moults before transforming into the bivalved cyprid stage. Nauplii are typically initially brooded by the parent, and are released as free-swimming larvae after the first moult. The second stage (the cyprid stage) lasts from days to weeks . During this part of the life cycle, the barnacle searches for a place to settle. It explores potential surfaces with modified antennule structures. Once it has found a potentially suitable spot, it attaches headfirst with its antennules by using a secreted glycoproteinous substance. As the larva exhausts its finite energy reserves, it becomes less selective in the settlement sites. If the spot is to its liking, the larva cements down permanently with another proteinaceous compound. As the larva accomplishes this process, it undergoes metamorphosis into a juvenile barnacle before developing into a mature adult.
藤壶有两个不同的幼虫阶段。在第一阶段，受精卵孵化成一只无节幼体，一只头部和一个telson的独眼幼虫，没有胸部或腹部。它经历了六次换羽，然后转变为双壳类cyprid阶段。Nauplii通常最初由亲本阉割，并在第一次换羽后作为自由游动的幼虫释放。第二阶段（cyprid阶段）持续数天至数周。在生命周期的这一部分，藤壶寻找一个安置的地方。它探索了具有改良天线结构的潜在表面。一旦它找到了一个可能合适的斑点，它就会通过使用分泌的糖蛋白物质首先与它的触角连接。随着幼虫耗尽其有限的能量储备，它在定居点的选择性降低。如果这个地方喜欢它，幼虫用另一种蛋白质化合物永久地凝固。随着幼虫完成这一过程，它会在变成成熟的成年人之前变态为幼年藤壶。

Barnacles are biofoulants, like many other organisms. A member of the phylum Arthropoda, barnacles have been considered obnoxious creatures in the marine environment. They usually adhere on wood, plastic, bamboo, glass, blue mussel shells, oyster shells, i.e., any type of hard surfaces. Barnacles damage water-submerged materials such as ship hulls, fishing nets, and cooling water intake channels of power plants by “wall-to-wall” adhesion on these surfaces, causing serious economic and environmental problems. In the past forty to fifty years, scientists have been working in search of an effective surface to be used as an antifoulant.
与许多其他生物一样，藤壶是生物污染物。作为节肢动物门的一员，藤壶被认为是海洋环境中令人讨厌的生物。它们通常粘附在木材，塑料，竹子，玻璃，蓝贻贝壳，牡蛎壳，即任何类型的硬表面上。藤壶通过这些表面上的“墙到墙”附着力破坏水下浸没的材料，例如船体，渔网和发电厂的冷却水进水通道，造成严重的经济和环境问题。在过去的四十到五十年里，科学家们一直致力于寻找一种有效的表面用作防污剂。

Antifouling properties of hydrogels 水凝胶的防污性能

In the laboratory, a number of researchers have carried out experiments to examine the settlement of different species of marine organisms on hard surfaces, such as glass, PS, PDMS, PE . James F. Schumacher et al. (2007) [1] studied the settlement behavior of the barnacle Balanus amphitrite on PDMS with different engineered topographies. Kenji Mori et al. (2006) [2] investigated the anti-fouling activity of linear polymer/silica hybrid materials, such as PVAc/silica and PMMA/silica against blue mussels. The former composite showed a comparatively higher repellent activity towards blue mussels. However, none of the materials have been observed to be very durable in marine environments for long term usage. Previously, no studies have been carried out using hydrogels against barnacles. Hydrogels have been chosen as an antifoulant because of their softness, non-toxicity, and long-term durability.
在实验室中，许多研究人员进行了实验，以检查不同种类的海洋生物在硬表面上的沉降，如玻璃，PS，PDMS，PE。詹姆斯·舒马赫等人。（2007）[1]研究了藤壶Balanus amphitrite的沉降行为在具有不同工程拓扑图的PDMS上。Kenji Mori等。（2006）[2]研究了线性聚合物/二氧化硅杂化材料（如PVAc /二氧化硅和PMMA /二氧化硅）对蓝贻贝的防污活性。前一种复合材料对蓝贻贝具有相对较高的驱避活性。然而，在长期使用中，没有观察到任何材料在海洋环境中非常耐用。以前，没有使用水凝胶对藤壶进行研究。水凝胶因其柔软性，无毒性和长期耐久性而被选为防污剂。

In laboratory testing (in vitro), Murosaki et al. (2009) [3] selected a number of hydrogels to investigate their antifouling characteristics against the barnacle Balanus amphitrite. In this test, hydrogels were categorized into two groups in terms of their antifouling behavior against barnacles. One group (Group-1: PHEMA, PHEA, PNaMPS, PAMPS, PNaSS, PDMAEA-Q, PAAc/PAAm DN , agarose, and PVA gels) showed strong antifouling performance irrespective of the elasticity (E) or swelling degree (q). On the other hand, the second group (Group-2: PAAm, PDMAAmm, PDMAPAA-Q, and PAMPS/PAAm DN gels) showed relatively weaker antifouling performance that was E- or q-dependent. In the latter case, a relatively high cyprid settlement was observed with increase in the elastic modulus of the gel. The number of barnacles that settled on the gels of Group-2 decreased with an increase in the swelling degree of the gels.
在实验室测试（体外）中，Murosaki等。（2009）[3]选择了一些水凝胶来研究它们对藤壶Balanus amphitrite的防污特性。在该试验中，水凝胶根据其对藤壶的防污性能分为两组。一组（组-1：PHEMA，PHEA，PNaMPS，PAMPS，PNaSS，PDMAEA-Q，PAAc / PAAm DN，琼脂糖和PVA凝胶）显示出强的防污性能，而与弹性（E）或溶胀度（q）无关。另一方面，第二组（第2组：PAAm，PDMAAmm，PDMAPAA-Q和PAMPS / PAAm DN凝胶）显示出相对较弱的防污性能，其依赖于E-或q-依赖性。在后一种情况下，随着凝胶弹性模量的增加，观察到相对高的cyprid沉降。沉降在第2组凝胶上的藤壶数量随着凝胶溶胀度的增加而减少。

The adhesion mechanism of barnacles, named “Easy Release” on hydrogels, has already been established. In this case, the “Easy Release” of initially attached cyprids is the main determinant of the conversion from random cyprid contact and surface exploration to settlement and metamorphosis. It should be noted that the “settlement” defined in this work required sufficiently strong and persistent attachment of the surface-contracting cyprid antennule tips (with cement) to trigger metamorphosis of the organism to the acorn barnacle form. When the adhesion strength is less than the contractile force of the retracting cyprid antennules, cyprids do not “settle” but wander aimlessly and eventually die without undergoing metamorphosis.
已经建立了藤壶的粘附机制，在水凝胶上称为“易释放”。在这种情况下，最初附着的cyprids的“易释放”是从随机cyprid接触和表面探测到沉降和变态的转换的主要决定因素。应该注意的是，在这项工作中定义的“沉降”要求表面收缩的cyprid触角尖端（用水泥）足够强大和持久地附着，以触发生物体变形为橡子藤壶形式。当粘附强度小于回缩的cyprid触针的收缩力时，cyprids不会“沉降”，而是漫无目的地游荡并最终在没有变态的情况下死亡。

Field Application of Anti-fouling Materials 防污材料的现场应用

Hydrogels were also treated in marine environments [4] to observe their long term (about one year) anti-fouling behavior against barnacles on agarose, κ-carrageenan, PAAm, PAMPS, PAAc, PAMPS /PAAm DN gel, PAAc/PAAm DN gel, PAAc/PAAm/PAAc TN gel, and PVA gel. In this research, two main obstacles in carrying out the experiment in marine environments were overcome. One was the weak mechanical strength of the gel and the other was the method of fixation of gel samples in marine environments. Although three different methods of fixation of the above gels were implemented in marine environments, the stainless frame method performed with mechanically strong PVA and the PAMPS/PAAm DN gel was found to be the most successful. In this case, the species of barnacles settled on gel surfaces were Megabalanus rosa, Fistulobalanus kondakovi, and Amphibalanus amphitrite and the other sessile organisms found were sponges, algae, and sea squirts.
水凝胶也在海洋环境中进行处理[4]，以观察它们对琼脂糖，κ-角叉菜胶，PAAm，PAMPS，PAAc，PAMPS / PAAm DN凝胶，PAAc / PAAm DN凝胶中藤壶的长期（约一年）防污行为。 ，PAAc / PAAm / PAAc TN凝胶和PVA凝胶。在这项研究中，克服了在海洋环境中进行实验的两个主要障碍。一个是凝胶的弱机械强度，另一个是在海洋环境中固定凝胶样品的方法。尽管在海洋环境中实施了三种不同的上述凝胶固定方法，但发现用机械强度PVA和PAMPS / PAAm DN凝胶进行的不锈钢框架方法是最成功的。在这种情况下，固定在凝胶表面的藤壶种类是Megabalanus rosa，Fistulobalanus kondakovi和Amphibalanus amphitrite以及发现的其他无柄生物是海绵，藻类和海鞘。

In the marine environment test, the degree of destruction of the surfaces PE, PAMPS/PAAm DN gel, and PVA gel, created by sessile barnacles, and the growth of these barnacles on different surfaces were investigated. The behaviors of barnacles and other sessile organisms were practically observed. The adjacent figure shows that a large number of barnacles adhered onto PE control surfaces compared with the gels. The red dashed line refers to the substratum area. Moreover, from the figure, it is evident how deformation occurred in the case of gels. However, the PE surface remained undistorted.
在海洋环境试验中，研究了由无柄藤壶产生的表面PE，PAMPS / PAAm DN凝胶和PVA凝胶的破坏程度，以及这些藤壶在不同表面上的生长。实际观察到藤壶和其他固着生物的行为。相邻图显示，与凝胶相比，大量藤壶粘附在PE控制表面上。红色虚线表示底层区域。而且，从图中可以看出，在凝胶的情况下如何发生变形。然而，PE表面保持不变形。

Moreover, deformation was also found in the case of barnacle basal plates. This deformation at the basal plates also agrees with that which occurred in the case of gel surfaces, meaning that a flat basal surface was observed on hard PE (E = 151 MPa). On the other hand, a very rough and concave basal surface was observed on the soft PVA gel surface (E = 0.09 MPa). On the PAMPS/PAAm DN gel, which was relatively rigid (E = 1.25 MPa) in comparison with the PVA gel, a slightly concave surface was observed.
此外，在藤壶基板的情况下也发现了变形。基板上的这种变形也与在凝胶表面的情况下发生的变形一致，这意味着在硬PE上观察到平坦的基底表面（E = 151MPa）。另一方面，在软PVA凝胶表面上观察到非常粗糙和凹陷的基底表面（E = 0.09MPa）。在PAMPS / PAAm DN凝胶上，与PVA凝胶相比，其相对刚性（E = 1.25MPa），观察到略微凹陷的表面。

This observation indicates a dependence of the morphology of the barnacle basal surface on the substratum on which it settled. In the case of soft surfaces, the barnacle was found to embed into the surface. This observation was also investigated by Berglin et al. [5] who used rigid PMMA and relatively soft PDMS surfaces. A concave shape of the barnacle base surface was observed in the case of PDMS surfaces.
该观察结果表明藤壶基面的形态依赖于其沉降的基质。在软表面的情况下，发现藤壶嵌入表面。Berglin等人也研究了这一观察结果。[5]谁使用刚性PMMA和相对柔软的PDMS表面。在PDMS表面的情况下观察到藤壶底面的凹形。

The growth of barnacles on PHCL PVA (physically cross-linked PVA) gels, PDMS, PAMPS/PAAm DN gels, and glass surfaces is being investigated in vitro. In this case, the observation will be carried out in three phases: observation of first, the settlement of cyprid larvae, second, the long-term growth progress of acorn barnacles, and finally, the relative size and morphology of barnacles.
在体外研究了在CLCL PVA（物理交联的PVA）凝胶，PDMS，PAMPS / PAAm DN凝胶和玻璃表面上的藤壶的生长。在这种情况下，观察将分三个阶段进行：首先观察，c c幼虫的沉降，第二，橡子藤壶的长期生长进程，最后是藤壶的相对大小和形态。

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