**1. Introduction**

Proteinoids, polymers made of amino acids by thermal condensation polymerization, are unique synthetic polymers studied by Fox and coworkers [1-7]. When present in certain concentrations in aqueous solutions, the proteinoids form small microscopic structures called "proteinoid microspheres" or protocells [4]. The proteinoid, made of most common amino acids, goes through a self-assembly process in specific conditions, as some of the amino acids incorporated into proteinoid chains are more hydrophobic than others, thus proteinoids cluster together like droplets of oil in water [5-7].

The amino acids, either natural or synthetic, are polymerized by step-growth polymerization in a special procedure discovered by Fox and Harada [8-12]. The procedure involves heating amino acids until they melt at first, and then the polymerization is initiated to give the proteinoid. The polymerization takes place at a relatively high temperature (e.g., 180 °C), in absence of a solvent or a catalyst, and in an inert atmosphere. The accepted explanation of this polymerization process is that glutamic acid is used as a solvent for the other monomers, as it is condensed into pyroglutamic acid. The pyroglutamic acid initiates the polymerization with the rest of the present amino acids [11-14]. A brief description of the polymerization process is shown in Figure 1.

An important advantage in using biodegradable polymers bearing one or more stereogen‐ ic centers- optically active polymers- is the high variety of features they offer, when used as carriers for drug delivery systems [15]. This study is intended to broaden the scope of

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biodegradable polymers by synthesizing new proteinoids carrying various stereogenic centers. The main goal is to provide a large choice of biodegradable proteinoids with predetermined characteristics, while using amino acids as building blocks. Hence, the new selection is based on chiral building blocks carrying positive/negative charge, hydrophilic/ hydrophobic nature or any desired combination of the above [16]. Homopolymers, random copolymers and block-copolymers of two amino acids or more can be designed and synthesized, presenting thereby new proteinoid materials with specific, desired nature. The large variety of amino acids, either natural or synthetic, makes it possible to obtain a large library of different proteinoids, by simply changing the amino acids ratios. One protei‐ noid is completely different from another, by the fact that they are made of different amino acid monomers. This fact provides each proteinoid special features, and possibly influen‐ ces the character of particles made from it [17-20].

Up until now, most, if not all, of the reported proteinoids in the literature were synthesized from at least four amino acids and possessed relatively low molecular weights [21,22]. Thus, high molecular weight proteinoids of narrow size distribution made of two to three natural amino acids, along with proteinoids containing poly(L-lactic acid) (PLLA) segments are presented in this study. Furthermore, the study presents NIR fluorescent proteinoid-based particles, which can be used for colon cancer detection. Some of the methods used have been published in a previous work [23].
