Poly(alkylene dicarboxylate)s constitute a family of biodegradable polymers with increasing interest for both commodity and speciality applications. Most of these polymers can be prepared from biobased diols and dicarboxylic acids such as 1,4-butanediol, succinic acid and carbohydrates. This review provides a current status report concerning synthesis, biodegradation and applications of a series of polymers that cover a wide range of properties, namely, materials from elastomeric to rigid characteristics that are suitable for applications such as hydrogels, soft tissue engineering, drug delivery systems and liquid crystals. Finally, the incorporation of aromatic units and α-amino acids is considered since stiffness of molecular chains and intermolecular interactions can be drastically changed. In fact, poly(ester amide)s derived from naturally occurring amino acids offer great possibilities as biodegradable materials for biomedical applications which are also extensively discussed.

The development of effective drug delivery systems (DDSs) is important for cancer and infectious disease treatment to overcome low bioavailability, rapid clearance and the toxicity of the therapeutic towards non-targeted healthy tissues. This review discusses how PEGylation, the attachment of poly(ethylene glycol) (PEG) molecules to nanoparticles (NPs), enhances drug pharmacokinetics by creating a “stealth effect”. We provide the synthesis methods for several PEG derivatives, their conjugation with NPs, proteins and characterization using modern analytical tools. This paper focuses particularly on covalent conjugation and self-assembly strategies for successful PEGylation and discusses the influence of PEG chain length, density and conformation on drug delivery efficiency. Despite the PEGylation benefits, there are several challenges associated with it, including immunogenicity and reduced therapeutic efficacy due to accelerated blood clearance. Therefore, the balance between PEGylation benefits and its immunogenic risks remains a critical area of investigation.

Development of materials with an antimicrobial activity is fundamental for different sectors, including medicine and health care, water and air treatment, and food packaging. Electrospinning is a versatile and economic technique that allows the incorporation of different natural, industrial, and clinical agents into a wide variety of polymers and blends in the form of micro/nanofibers. Furthermore, the technique is versatile since different constructs (e.g. those derived from single electrospinning, co-electrospinning, coaxial electrospinning, and miniemulsion electrospinning) can be obtained to influence the ability to load agents with different characteristics and stability and to modify the release behaviour. Furthermore, antimicrobial agents can be loaded during the electrospinning process or by a subsequent coating process. In order to the mitigate burst release effect, it is possible to encapsulate the selected drug into inorganic nanotubes and nanoparticles, as well as in organic cyclodextrine polysaccharides. In the same way, processes that involve covalent linkage of bactericide agents during surface treatment of electrospun samples may also be considered.; The present review is focused on more recent works concerning the electrospinning of antimicrobial polymers. These include chitosan and common biodegradable polymers with activity caused by the specific load of agents such as metal and metal oxide particles, quaternary ammonium compounds, hydantoin compounds, antibiotics, common organic bactericides, and bacteriophages.Peer ReviewedPostprint (published version

The capacity to load bacteriophages into electrospun nanofibers of two representative biocompatible polymers has been evaluated, paying special attention to the possibility of preserving their antibacterial activity. Specifically, the work involves the following steps: (a) Evaluation of the effect of the applied electrical field on the phage activity; (b) evaluation of the activity when a lyophilization process could be avoided by using water soluble polymers (e.g., poly(ethylene glycol); (c) evaluation of the activity when dissolution of the polymer requires an organic solvent and lyophilization is theoretically necessary. In this case, a poly(ester urea) (PEU) derived from the natural L-leucine amino acid has been considered. Adsorption of commercial bacteriophage preparations into calcium carbonate particles was demonstrated to be a promising methodology to avoid lyophilization and keep the initial bactericide activity at a maximum. Phagestaph and Fersis bacteriophage commercial preparations have been selected for this study due to their specific activity against Staphylococci (e.g., S. aureus) and Streptococci (e.g., S. pyogenes) bacteria. Adhesion and proliferation assays using epithelial cells demonstrated the biocompatibility of both unloaded and bacteriophage-loaded PEU scaffolds, although some slight differences were observed depending on the type of bacteriophage and the selected preparation methodology.

Combinatorially synthesized materials, especially cationic polymers (CPs), with gene transfection function hold great promise in nanotechnology. However, the main limitations of the existing CPs [such as polyethylenimine (PEI), poly-l-arginine, or polyamidoamine-based dendrimers] as gene transfection agents are high cytotoxicity in the physiological environment. We have developed novel CPs composed of polyamines—endogeneous tetraamine spermine (Spm) and synthetically made triamine N-(2-aminoethyl)-1,3-propanediamine (Apd) for incorporating sec-amino groups and imparting PEI-like structure to the CP backbones. Naturally occurring building blocks such as amino acid arginine (R) was also used for incorporating guanidine-groups into the CPs. The cytotoxicity of resulting CPs—polyureas (PUs) and polyamides such as polysuccinamides and R-attached polymalamides was evaluated using murine and human fibroblasts and carcinoma cell lines. The cell compatibility screening revealed that the CPs made of Apd are less cytotoxic compared to Spm-based analogues. From the novel polymer library, total of six polymers were further studied for oligonucleotide (pDNA) complexation and transfection abilities. Highly water-soluble CPs formed nano-sized polyplexes with pDNA at rather low CP/pDNA weight ratios and showed less cytotoxicity and higher transfection ability compared to widely used PEI as well as commercially available transfection agents. Furthermore, new CPs showed selective transfection activity toward certain cell lines (4T1, HeLa, NIH3T3, and CCD 27SK), which is important for their potential applications in gene therapy.

Tissue engineering approaches appear nowadays highly promising for the regeneration of injured/diseased tissues. Biomimetic scaffolds are continuously been developed to act as structural support for cell growth and proliferation as well as for the delivery of cells able to be differentiated, and also of bioactive molecules like growth factors and even signaling cues. The current research concerns materials employed to develop biological scaffolds with improved features as well as complex preparation techniques. In this work, hybrid systems based on natural polymers are discussed and the efforts focused to provide new polymers able to mimic proteins and DNA are extensively explained. Progress on the scaffold fabrication technique is mentioned, those processes based on solution and melt electrospinning or even on their combination being mainly discussed. Selection of the appropriate hybrid technology becomes vital to get optimal architecture to reasonably accomplish the final applications. Representative examples of the recent possibilities on tissue regeneration are finally given.