Description

Single-Chain polymer Nanoparticles (SCNPs) represent a precisely characterized and meticulously measured category of polymer nanoparticles. Advances in polymer science in recent decades have facilitated the development of various intramolecular crosslinking systems, resulting in particles within the size range of 2-15 nm. This size range aligns with that of proteins, rendering SCNPs a particularly intriguing class of nanoparticles for biomedical applications. The high precision in SCNP design and the ease of their functionalization have spurred growing interest in research. This review outlines various crosslinking systems, the synthesis of functional SCNPs and the diverse array of biomedical applications that have been explored.

Artificial nanomaterials

However, one can argue that Nanoparticles (NPs) have a significant historical presence in medicine. While nanosilver's efficacy against bacterial infections stands out as a prominent example, the application of nanosized agents to modulate immune responses has been in practice for many years. Even before the widespread recognition of the term "nanomaterials," colloidal gold was utilized in the treatment of conditions such as rheumatoid arthritis and alum served as an adjuvant in various vaccines, both containing nanomaterials. Therefore, it is inaccurate to claim that there is no prior experience regarding the effects of artificial nanomaterials on the human body. The extensive historical use of NPs spans diverse practical applications, particularly within the realm of medicine. This is particularly relevant as these agents are intentionally applied to individuals with compromised health, often administered locally and in doses that far exceed those encountered in unintentional workplace exposures. Lipid-based nanomedicines stand at the forefront of clinical success within the realm of nanomedicine, holding immense promise for treating various diseases. Among these, the classic liposome formulation reigns as the most triumphant. While alternative lipid-based formulations like SLNs, lipid-drug conjugates and lipid nanostructures have undergone extensive preclinical scrutiny, their clinical viability remains to be fully realized. In addition to synthetic drug molecules, lipidbased nanomedicines have demonstrated potential in delivering biological drugs and imaging agents. The convergence of nanotechnology, material science and pharmaceutical science promises to propel the development of clinically effective nanomedicines. Furthermore, the future may see the emergence of stimuli-responsive or targeted lipid nanomedicines, offering further advancements beyond current capabilities.

Biodegradable nanoparticles

Biodegradable Nanoparticles (NPs) offer significant advantages in controlled drug delivery, serving to ensure both biocompatibility and responsive drug release. Various methods have been explored to imbue stimuli responsiveness into such nanoparticles, including pH modulation, temperature variations and UV irradiation. A noteworthy instance of responsive biodegradable nanoparticles involves a polymer incorporating 2-(acetoacetoxy)ethyl methacrylate, which was functionalized with a monofunctional enamine to facilitate exchange with ethylene diamine. This chemical reaction was utilized for covalent crosslinking of the nanoparticles, with enamine bond cleavage observed under acidic conditions, as confirmed by 1H NMR spectroscopy. This category of nanoparticles exhibits spontaneous enamine formation and exchange with the bifunctional crosslinker, while also being susceptible to degradation via hydrolysis. Since many polymers utilized in the formation of Self-Crosslinking Nanoparticle (SCNP) structures are synthesized through radical polymerization, their molecular structure primarily comprises carbon-carbon bonds, known for their resistance to degradation. An innovative approach to introduce degradability to vinyl polymers involves radical ring opening polymerization of cyclic vinyl monomers. Through this method, SCNP structures with main chain degradability were successfully developed. These structures were derived from copolymers incorporating 2- Methylene-1,3-Dioxepane (MDO) and an NHS-ester functional monomer, crosslinked with diamines. Importantly, the degradation mechanism primarily involves ester hydrolysis of the ring-opened MDO monomer within the polymer backbone, facilitating the breakdown of the main chain. Biocompatibility stands as the prevailing term in characterizing the requisite biological standards for biomaterials employed in medical devices. It encompasses the material's capability to elicit a suitable host response within a defined application. The evaluation of biocompatibility or safety pertains to discerning such a response. This is covered include biocompatibility, materials utilized in medical devices and both in vitro and in vivo testing methodologies for biocompatibility.