A Comprehensive Survey of Recent Advancements in Molecular Communication <s> A. Information Particles <s> This investigation presents a quantitative analysis of the asymmetric transmembrane lipid packing geometry in egg phosphatidylcholine vesicles. The analysis uses hydrodynamic and nuclear magnetic resonance data obtained for homogeneous egg phosphatidylcholine vesicles and demonstrates that the average area per lipid head group and effective length of the lipid are greater on the outer monolayer than on the inner monolayer of the egg phosphatidylcholine vesicle. Results also indicate that the bilayer of the egg phosphatidylcholine vesicles has an asymmetrical interface through its center. <s> BIB001 </s> A Comprehensive Survey of Recent Advancements in Molecular Communication <s> A. Information Particles <s> Capacity for information in biological molecules is traditionally thought to reside in the primary sequence of proteins and RNA, recorded in the DNA. With the exception of some RNA molecules, proteins, if not structural, carry their information in binding sites for substrates of reactions, or in binding sites for control molecules. Some proteins bind to complex carbohydrates in a carbohydrate-specific fashion, including enzymes, lectins and antibodies. These carbohydrates, assembled by sequential glycosyl transferases, also carry biological information, the other side of which is a binding protein that recognizes a specific sugar monosaccharides, sequence, anomerity, linkage, ring size, branching and substitution. It is the latter 7 parameters, however, that give carbohydrates a very large potential for information-carrying capacity in a short sequence. An exponentially growing body of knowledge exists in this aspect of carbohydrate function. <s> BIB002 </s> A Comprehensive Survey of Recent Advancements in Molecular Communication <s> A. Information Particles <s> Recent developments in the application of micro- and nanosystems for drug administration include a diverse range of new materials and methods. New approaches include the on-demand activation of molecular interactions, novel diffusion-controlled delivery devices, nanostructured 'smart' surfaces and materials, and prospects for coupling drug delivery to sensors and implants. Micro- and nanotechnologies are enabling the design of novel methods such as radio-frequency addressing of individual molecules or the suppression of immune response to a release device. Current challenges include the need to balance the small scale of the devices with the quantities of drugs that are clinically necessary, the requirement for more stable sensor platforms, and the development of methods to evaluate these new materials and devices for safety and efficacy. <s> BIB003 </s> A Comprehensive Survey of Recent Advancements in Molecular Communication <s> A. Information Particles <s> Abstract Molecular communication uses molecules (i.e., biochemical signals) as an information medium and allows biologically and artificially created nano- or microscale entities to communicate over a short distance. It is a new communication paradigm; it is different from the traditional communication paradigm, which uses electromagnetic waves (i.e., electronic and optical signals) as an information medium. Key research challenges in molecular communication include design of system components (i.e., a sender, a molecular propagation system, a receiver, and a molecular communication interface) and mathematical modeling of each system component as well as entire systems. We review all research activities in molecular communication to date, from its origin to recent experimental studies and theoretical approaches for each system component. As a model molecular communication system, we describe an integrated system that combines a molecular communication interface (using a lipid vesicle embedded with channel-forming proteins), a molecular propagation system (using microtubule motility on kinesin molecular motors and DNA hybridization), and a sender/receiver (using giant lipid vesicles embedded with gemini-peptide lipids). We also present potential applications and the future outlook of molecular communication. <s> BIB004 </s> A Comprehensive Survey of Recent Advancements in Molecular Communication <s> A. Information Particles <s> Among the molecular milieu of the cell, the membrane bilayer stands out as a complex and elusive synthetic target. We report a microfluidic assembly line that produces uniform cellular compartments from droplet, lipid, and oil/water interface starting materials. Droplets form in a lipid-containing oil flow and travel to a junction where the confluence of oil and extracellular aqueous media establishes a flow-patterned interface that is both stable and reproducible. A triangular post mediates phase transfer bilayer assembly by deflecting droplets from oil, through the interface, and into the extracellular aqueous phase to yield a continuous stream of unilamellar phospholipid vesicles with uniform and tunable size. The size of the droplet precursor dictates vesicle size, encapsulation of small-molecule cargo is highly efficient, and the single bilayer promotes functional insertion of a bacterial transmembrane pore. <s> BIB005
Information-carrying particles propagate from the transmitter to the receiver in the channel medium. The structure and size of these information particles may affect how they propagate in the environment. For example, increasing the size of the information particle changes the diffusion coefficient and hence the diffusion process. To make the molecular communication channel more reliable, information particles need to be chemically stable and robust against environmental noise and interference from other molecules and particles. Moreover, information particles may degrade or denature over time in the environment. For example, molecular deformation and cleavage caused by enzymatic attacks or changes in pH in the environment may degrade the information particles BIB004 . Due to degradation of particles, the transmitter can release a large number of information particles, or alternatively encapsulate the information-carrying particles inside liposomes that separate the channel environment and the information particles. Liposomes are lipid bilayer structures that can encapsulate different proteins and particles  . Figure 4 shows the structure of the liposome. It contains two layers of lipid molecules, where one side of the lipid is hydrophobic (repelled from water) and the other side is hydrophilic (attracted towards water). It separates the aqueous environment inside the liposome from the outside of the liposome. In BIB001 the relationship between the number of lipid molecules and the liposome's wall thickness and radius is derived and tested experimentally. In BIB005 , a chemical assembly line for generation of lipid vesicles and encapsulation process is presented. Some examples of information particles used in nature by biological systems include hormones, pheromones, neurotransmitters, intracellular messengers, and deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) molecules. Information particles can also be synthesized for specific purposes as demonstrated in drug delivery. For example, in BIB003 nanoparticles are used to target particular tissue types. All these particle can be potentially be used as information particles for transferring information from the transmitter to the receiver. In molecular communication, information can be encoded in to the structure (type of) the information particles, in the number of information particles, or in the release timing. The encoding and modulation schemes will be discussed in more details in Section V. Another issue to consider when selecting the information particles is the chemical bandwidth. For example, small chemical molecules such as hormones or pheromones or carbohydrates can be sent at short or long ranges, are stable in most channels, and give 10 2 -10 6 unique combinations BIB002 . However, the problem of generating and detecting these different combinations can be challenging. Dial-a-Molecule is project that tackles this problem with the goal of rapidly synthesizing compounds  . The information particle at macroscales can be any volatile chemical or gas, for over the air applications, or liquids for aqueous environments. For most practical applications, these chemicals must be non-toxic and safe for humans and the environment. At macroscales, detecting individual molecules would be very difficult. Therefore, in practice concentration of chemicals and chemical mixtures would be used as carries of information.