Relevant properties of gold nanoparticles, such as stability and biocompatibility, together with their peculiar optical and electronic behavior, make them excellent candidates for medical and biological applications. This review describes the different approaches to the synthesis, surface modification, and characterization of gold nanoparticles (AuNPs) related to increasing their stability and available features useful for employment as drug delivery systems or in hyperthermia and photothermal therapy. The synthetic methods reported span from the well-known Turkevich synthesis, reduction with NaBH4 with or without citrate, seeding growth, ascorbic acid-based, green synthesis, and Brust–Schiffrin methods. Furthermore, the nanosized functionalization of the AuNP surface brought about the formation of self-assembled monolayers through the employment of polymer coatings as capping agents covalently bonded to the nanoparticles. The most common chemical–physical characterization techniques to determine the size, shape and surface coverage of AuNPs are described underlining the structure–activity correlation in the frame of their applications in the biomedical and biotechnology sectors.

Children with insulin-dependent diabetes mellitus (IDDM) were examined for scleroderma-like changes of digital sclerosis and joint contractures. Of the 104 patients, 19 (18%) demonstrated these features; five patients had both multiple joint involvement and skin changes; three were studied in detail. All three had restrictive pulmonary disease. Histopathology of skin in these three patients demonstrated increased accumulation of collagen in the lower dermis. In two of the patients, the extractability of collagen in 0.5 N acetic acid was decreased by about 50% as compared with normal controls, which suggests increased cross-linkage of collagen. In addition, the mean nonenzymatic glycosylation of collagen in these three patients was 13 times that of controls. The results indicate that distinct histopathologic and biochemical changes can be detected in the skin of these patients. The results further support the hypothesis that nonenzymatic glycosylation may alter the turnover of collagen, thus contributing to the development of a scleroderma-like syndrome with skin, joint, and pulmonary findings in patients with IDDM.

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