What are Xenobots? Summary

• Living “Robots”: Xenobots are tiny, living “machines” created from frog embryonic cells (specifically, from the African clawed frog, *Xenopus laevis*).
• Not Traditional Robots: They’re not made of metal or plastic. They’re entirely biological, made of living cells. But, “robots” due to goal-seeking programming aspects and behaviours.
• Self-Assembled: They are *not* genetically modified. Their unique structures and behaviors arise from the way the cells are brought together and interact.
• Skin and Heart Cells: They’re typically made from a combination of skin cells (which provide structure) and heart muscle cells (which provide movement).
• Motile: Xenobots can move around in their environment, propelled by the beating of cilia (hair-like structures) or by the contractions of heart muscle cells.
• Emergent Behavior: They exhibit surprising “emergent” behaviors, like moving in circles or straight lines, aggregating debris, and even self-repairing after being damaged.
• No Brain, No Nervous System: Xenobots don’t have brains or nervous systems. Their behavior arises from the interactions of the cells themselves.
• Programmable (to an Extent): Scientists can influence the shape and behavior of xenobots by changing the initial arrangement of cells and the environment they’re placed in.
• Implications: Xenobots have implications for regenerative medicine, drug delivery, environmental cleanup, and our understanding of how cells communicate and organize themselves.

A New Form of Life: Biological Machines from Frog Cells

Imagine a tiny, living machine, smaller than a grain of sand, that can move around, interact with its environment, and even perform simple tasks. This is not science fiction; it’s a reality thanks to the creation of *xenobots*.

Xenobots are a novel form of life, created in the lab from the cells of the African clawed frog (*Xenopus laevis* – hence the name “xeno,” meaning “foreign” or “strange”). They represent a groundbreaking intersection of biology, robotics, and computer science.

They are different from:

• Traditional robots: which require physical control (programming movements);
• Genetically-modified cells: where specific cell instructions get re-programmed (change in gene/expression.)

Not Your Typical Robot: Flesh, Not Metal

It’s important to emphasize that xenobots are *not* robots in the traditional sense. They’re not made of metal, plastic, or electronic circuits. They’re entirely *biological*, made of living cells. There isn’t any wiring/electronics for its operation and behavior, it comes naturally with cell organization. The reason scientists have sometimes called them ‘robots’ is due to goal-seeking and collective cell organizational ability they possess. Their programmable actions and behaviour exhibit.

So, what makes them “machines”? It’s their ability to perform specific tasks, guided by their physical structure and the inherent properties of their cells. They are *designed* (in a way we’ll discuss shortly) to achieve certain outcomes, just like a machine is designed to perform a function.

Self-Assembly: Building from the Bottom Up

One of the most remarkable things about xenobots is that they are *self-assembled*. Scientists don’t painstakingly build them cell by cell. Instead, they take embryonic cells from the frog, separate them, and then bring them together in a specific way. The cells then *spontaneously* organize themselves into the xenobot structure.

This self-assembly is a testament to the inherent ability of cells to communicate, cooperate, and build complex structures. It’s like taking a pile of bricks and seeing them spontaneously arrange themselves into a wall, without any external intervention.

Skin and Heart: The Building Blocks of Xenobots

Xenobots are typically made from two types of frog embryonic cells:

• Skin Cells (Epithelial Cells): These provide the structure and “skin” of the xenobot.
• Heart Muscle Cells (Cardiomyocytes): These cells naturally contract, providing the force for movement.
• Cilia Cells Another type that also demonstrate “self powered” behaviors – and crucial for building Xenobots

By combining these two cell types in different arrangements, researchers can create xenobots with different shapes and movement capabilities.

Movement and Behavior: A Life of Their Own

Once assembled, xenobots are placed in a simple aqueous solution (like slightly salty water), and they begin to *move*. This movement can take various forms:

• Circular Motion: Some xenobots move in circles.
• Linear Motion: Others move in a more or less straight line.
• Random Movement: Some exhibit more random, undirected movement.

The movement is driven by the rhythmic contractions of the heart muscle cells or by the beating of *cilia* (tiny hair-like structures) on the surface of the skin cells. It’s like a tiny, biological motor, powering the xenobot’s locomotion.

Emergent Behavior: Surprising Capabilities

Beyond simple movement, xenobots exhibit some surprising “emergent” behaviors – behaviors that are not explicitly programmed into the individual cells but arise from their interactions:

• Debris Aggregation: Some xenobots can spontaneously push small particles in their environment together into piles.
• Self-Repair: If a xenobot is cut or damaged, it can often *repair itself*, re-assembling its structure and restoring its movement.
• New Reproduction Method:Scientists had witnessed an unprecedented reproductive strategy: Instead of sexual/asexual reproductions typically found in organic life, the free-cells build new “baby xenobots” in a vastly distinct process.

These emergent behaviors are particularly fascinating because xenobots *don’t have brains or nervous systems*. Their behavior arises solely from the interactions of the cells themselves, demonstrating a kind of “basal cognition” or collective intelligence.

“Programming” Xenobots: Design by Evolution

While xenobots are self-assembled, researchers can influence their shape and behavior in a few ways:

• Initial Cell Arrangement: By changing the way the skin and heart cells are initially brought together, they can influence the final form of the xenobot.
• Environmental Conditions: Changing the properties of the surrounding solution (e.g., its salinity or viscosity) can also affect xenobot behavior.
• Computational Design: Researchers have used *evolutionary algorithms* on computers to design xenobots with specific capabilities. The algorithm “evolves” virtual xenobots, selecting for those that best perform a desired task (like moving in a straight line or collecting debris). The designs generated by the algorithm can then be used as blueprints for creating real xenobots.

Implications and Applications: A New Frontier

Xenobots are a very new technology, and their long-term potential is still being explored. But they have already generated significant excitement in several fields:

• Regenerative Medicine: Understanding how cells self-organize and communicate in xenobots could provide insights into tissue regeneration and wound healing.
• Drug Delivery: Xenobots could potentially be used to deliver drugs to specific locations in the body.
• Environmental Cleanup: They could be designed to collect microplastics or other pollutants from the environment.
• Understanding Basal Cognition: Xenobots provides key test model: demonstrating “intelligent” processes can emerge outside of typical genetics and standard expectations in biology. They showcase self-rearrangement into functional structures. These “free cells”, from traditional top-down signals of frog skin, shows never-before-witnessed structures and problem-solving abilities (such as, self replication using parts from immediate enviornment) that are simply not found inside any single-cell instruction set – it’s not just random jumble: instead it performs new abilities using available tools on hand (frog cillia, which typically exists for completely different tasks).
• Fundamental Biology: They offer a new platform for studying how cells communicate, cooperate, and organize themselves into complex structures.

Xenobots are a powerful demonstration of the plasticity and potential of living systems. They challenge our traditional definitions of life, robots, and what’s possible with biological design. They represent a truly exciting new frontier in science and technology.

什么是异种机器人 (Xenobots)？摘要

• 活的“机器人”： 异种机器人是由青蛙胚胎细胞（特别是来自非洲爪蟾 *Xenopus laevis*）产生的微型活体“机器”。
• 不是传统机器人： 它们不是由金属或塑料制成的。它们完全是生物的，由活细胞组成。但是，由于具有目标导向的编程方面和行为，因此被称为“机器人”。
• 自组装： 它们*不是*基因改造的。它们独特的结构和行为源于细胞结合和相互作用的方式。
• 皮肤和心脏细胞： 它们通常由皮肤细胞（提供结构）和心肌细胞（提供运动）的组合制成。
• 能动的： 异种机器人可以在它们的环境中移动，由纤毛（毛发状结构）的跳动或心肌细胞的收缩推动。
• 涌现行为： 它们表现出令人惊讶的“涌现”行为，如绕圈或直线移动、聚集碎片，甚至在受损后进行自我修复。
• 没有大脑，没有神经系统： 异种机器人没有大脑或神经系统。它们的行为源于细胞本身的相互作用。
• 可编程（在一定程度上）： 科学家可以通过改变细胞的初始排列和它们所处的环境来影响异种机器人的形状和行为。
• 启示： 异种机器人对再生医学、药物输送、环境清理以及我们对细胞如何沟通和组织自身的理解具有重要意义。

一种新的生命形式：来自青蛙细胞的生物机器

想象一个微小的活体机器，比一粒沙子还小，可以在周围移动，与环境互动，甚至执行简单的任务。这不是科幻小说；由于*异种机器人*的创造，这已成为现实。

异种机器人是一种新型生命形式，在实验室中由非洲爪蟾 (*Xenopus laevis* —— 因此得名“xeno”，意思是“外来的”或“奇怪的”) 的细胞产生。它们代表了生物学、机器人学和计算机科学的开创性交叉。

它们不同于：

• 传统机器人：需要物理控制（编程运动）；
• 转基因细胞：其中特定的细胞指令被重新编程（基因/表达发生变化）。

不是典型的机器人：肉体，而不是金属

重要的是要强调，异种机器人*不是*传统意义上的机器人。它们不是由金属、塑料或电子电路制成的。它们完全是*生物*的，由活细胞组成。它的运作和行为没有任何接线/电子设备，它自然而然地伴随着细胞组织。科学家们有时称它们为“机器人”的原因是由于它们具有目标导向和集体细胞组织能力。它们表现出可编程的动作和行为。

那么，是什么让它们成为“机器”呢？这是它们执行特定任务的能力，受其物理结构和细胞固有特性的引导。它们被*设计*（以我们稍后将讨论的方式）来实现某些结果，就像机器被设计来执行功能一样。

自组装：从头开始构建

关于异种机器人最 remarkable 的事情之一是它们是*自组装*的。科学家们不会煞费苦心地逐个细胞地构建它们。相反，他们从青蛙身上取出胚胎细胞，将它们分离，然后以特定的方式将它们组合在一起。然后细胞*自发地*组织成异种机器人结构。

这种自组装证明了细胞固有的沟通、合作和构建复杂结构的能力。这就像拿一堆砖头，看到它们自发地排列成一堵墙，而无需任何外部干预。

皮肤和心脏：异种机器人的构建块

异种机器人通常由两种类型的青蛙胚胎细胞制成：

• 皮肤细胞（上皮细胞）： 这些细胞提供了异种机器人的结构和“皮肤”。
• 心肌细胞（心肌细胞）： 这些细胞自然收缩，提供运动的力量。
• 纤毛细胞：另一种也表现出“自供电”行为的类型 —— 对于构建异种机器人至关重要

通过以不同的排列组合这两种细胞类型，研究人员可以创造出具有不同形状和运动能力的异种机器人。

运动和行为：自己的生命

组装完成后，异种机器人被放置在一个简单的水溶液中（如微咸水），它们开始*移动*。这种运动可以采取多种形式：

• 圆周运动： 一些异种机器人绕圈移动。
• 直线运动： 其他异种机器人或多或少地沿直线移动。
• 随机运动： 有些表现出更随机、无方向的运动。

这种运动是由心肌细胞的有节奏收缩或皮肤细胞表面的*纤毛*（微小的毛发状结构）的跳动驱动的。这就像一个微小的生物马达，为异种机器人的运动提供动力。

涌现行为：令人惊讶的能力

除了简单的运动之外，异种机器人还表现出一些令人惊讶的“涌现”行为 —— 这些行为不是明确编程到单个细胞中，而是由它们的相互作用产生的：

• 碎片聚集： 一些异种机器人可以自发地将环境中的小颗粒推到一起成堆。
• 自我修复： 如果异种机器人被切割或损坏，它通常可以*自我修复*，重新组装其结构并恢复其运动。
• 新的繁殖方法：科学家们见证了一种前所未有的繁殖策略：异种机器人不是像有机生命中通常发现的那样进行有性/无性繁殖，而是以一种截然不同的过程构建新的“婴儿异种机器人”。

这些涌现行为特别令人着迷，因为异种机器人*没有大脑或神经系统*。它们的行为完全来自细胞本身的相互作用，展示了一种“基础认知”或集体智慧。

“编程”异种机器人：通过进化进行设计

虽然异种机器人是自组装的，但研究人员可以通过几种方式影响它们的形状和行为：

• 初始细胞排列： 通过改变皮肤和心脏细胞最初结合在一起的方式，它们可以影响异种机器人的最终形态。
• 环境条件： 改变周围溶液的特性（例如，其盐度或粘度）也会影响异种机器人的行为。
• 计算设计： 研究人员在计算机上使用了*进化算法*来设计具有特定功能的异种机器人。该算法“进化”虚拟异种机器人，选择最能执行所需任务的异种机器人（如沿直线移动或收集碎片）。然后可以将算法生成的设计用作创建真实异种机器人的蓝图。

意义和应用：一个新前沿

异种机器人是一项非常新的技术，它们的长期潜力仍在探索中。但它们已经在几个领域引起了极大的兴奋：

• 再生医学： 了解异种机器人中细胞如何自组织和通讯可以为组织再生和伤口愈合提供见解。
• 药物输送： 异种机器人有可能被用来将药物输送到体内的特定位置。
• 环境清理： 它们可以被设计用来从环境中收集微塑料或其他污染物。
• 理解基础认知： 异种机器人提供了一个关键的测试模型：证明“智能”过程可以在典型的遗传学和生物学中的标准预期之外出现。它们展示了自发重排成功能性结构。 这些“游离细胞”，来自青蛙皮肤的传统自上而下的信号，显示出前所未见的结构和解决问题的能力（例如，使用手头的可用工具（青蛙纤毛，通常存在于完全不同的任务中）进行自我复制），这些能力在任何单细胞指令集中都找不到 —— 它不仅仅是随机的混乱：相反，它使用手头的可用工具执行新的能力。
• 基础生物学： 它们提供了一个新的平台来研究细胞如何沟通、合作并将自己组织成复杂的结构。

异种机器人有力地证明了生命系统的可塑性和潜力。它们挑战了我们对生命、机器人以及生物设计可能性的传统定义。它们代表了科学技术中一个真正令人兴奋的新前沿。