Silver nanoparticles are one of the most important materials in the nanotechnology industry. Additionally, the protein corona is emerging as a key entity at the nanobiointerface; thus, a comprehensive understanding of the interactions between proteins and silver nanoparticles is imperative. Therefore, literature reporting studies involving both single molecule protein coronas (i.e., bovine and human serum albumin, tubulin, ubiquitin and hyaluronic-binding protein) and complex protein coronas (i.e., fetal bovine serum and yeast extract proteins) were selected to demonstrate the effects of protein coronas on silver nanoparticle cytotoxicity and antimicrobial activity. There is evidence that distinct and differential protein components may yield a “protein corona signature” that is related to the size and/or surface curvature of the silver nanoparticles. Therefore, the formation of silver nanoparticle protein coronas together with the biological response to these coronas (i.e., oxidative stress, inflammation and cytotoxicity) as well as other cellular biophysicochemical mechanisms (i.e., endocytosis, biotransformation and biodistribution) will be important for nanomedicine and nanotoxicology. Researchers may benefit from the information contained herein to improve biotechnological applications of silver nanoparticles and to address related safety concerns. In summary, the main aim of this mini-review is to highlight the relationship between the formation of silver nanoparticle protein coronas and toxicity.

The transport and the delivery of drugs through nanocarriers is a great challenge of pharmacology. Since the production of liposomes to reduce the toxicity of doxorubicin in patients, a plethora of nanomaterials have been produced and characterized. Although it is widely known that elementary properties of nanomaterials influence their in vivo kinetics, such interaction is often poorly investigated in many preclinical studies. The present study aims to evaluate the actual effect of size and shape on the biodistribution of a set of gold nanoparticles (GNPs) after intravenous administration in mice. To this goal, quantitative data achieved by inductively coupled plasma mass spectrometry and observational results emerging from histochemistry (autometallography and enhanced dark-field hyperspectral microscopy) were combined. Since the immune system plays a role in bionano-interaction we used healthy immune-competent mice. To keep the immune surveillance on the physiological levels we synthesized endotoxin-free GNPs to be tested in specific pathogen-free animals. Our study mainly reveals that (a) the size and the shape greatly influence the kinetics of accumulation and excretion of GNPs in filter organs; (b) spherical and star-like GNPs showed the same percentage of accumulation, but a different localization in liver; (c) only star-like GNPs are able to accumulate in lung; (d) changes in the geometry did not improve the passage of the blood brain barrier. Overall, this study can be considered as a reliable starting point to drive the synthesis and the functionalization of potential candidates for theranostic purposes in many fields of research.

Although the formation mechanism of biogenically metallic nanoparticles is broadly associated to enzyme mediation, major attention has been given to the role of proteins and peptides in oxido-reduction of metallic ions leading to these nanostructures. Among the wide range of biomolecules that can act not only as capping agents but also as non-enzymatic agents to form nanoparticles, disulphide bridge-containing peptides and amino acids particularly stand out. The literature proposes that they actively participate in the process of nanoparticles' synthesis, with thiols groups and disulphide bridge moieties as the reaction catalytic sites. Similarly, denaturated enzymes containing exposed S-S or S-H moieties are also able to reduce metallic ions to form nanoparticles. This mini-review is focused on the biogenic synthesis of metallic nanoparticles such as gold, silver, copper, platinum, palladium, lead and selenium, in which proteins, peptides, reductases and even oxido-reductases act as non-enzymatic catalysts of the reduction reaction, opening economically and ecologically favourable perspectives in the nanoparticles synthesis field.

Described here is an anticancer material based on colloidal mesoporous silica nanoparticles (MSNs) functionalized with doxorubicin (DOX), and incorporated into Pluronic F127 hydrogels for prolonged release, with a potential therapeutic application for prostate cancer treatment. The MSNs have spherical morphology, size of about 60 nm, surface area of 970 cm 2 g −1 and average pore width of 2.0 nm. A high colloidal stability for the MSNs in the physiological medium used for in vivo administration (NaCl 0.9% w/v) could be attained in the presence of PF127 (from 5 to 18 wt %), where depletion repulsion forces prevent MSN agglomeration. By conjugating DOX, MSN and PF127 (18 wt %) in NaCl 0.9%, the hybrid system has a gelation temperature of 21 °C, which allowed its in vivo administration in the liquid form and further in situ gelation, generating a drug depot system inside the animals after peritoneal injection. The systems were tested in rats with chemically induced prostate cancer and, after this treatment, histopathological analyses confirmed (i) a reduction in the frequency of aggressive tumors; (ii) that the antitumor effect was dependent on MSN concentration; and most importantly (iii) the reduction of DOX intrinsic cardiotoxicity, indicating that the MSNs play a cardioprotective effect.

We report here that the surface topography of colloidal mesoporous silica nanoparticles (MSNs) plays a key role on their bionano-interactions by driving the adsorption of biomolecules on the nanoparticle through a matching mechanism between the surface cavities characteristics and the biomolecules stereochemistry. This conclusion was drawn by analyzing the biophysicochemical properties of colloidal MSNs in the presence of single biomolecules, such as alginate or bovine serum albumin (BSA), as well as dispersed in a complex biofluid, such as human blood plasma. When dispersed in phosphate buffered saline media containing alginate or BSA, monodisperse spherical MSNs interact with linear biopolymers such as alginate and with a globular protein such as bovine serum albumin (BSA) independently of the surface charge sign (i.e. positive or negative), thus leading to a decrease in the surface energy and to the colloidal stabilization of these nanoparticles. In contrast, silica nanoparticles with irregular surface topographies are not colloidally stabilized in the presence of alginate but they are electrosterically stabilized by BSA through a sorption mechanism that implies reversible conformation changes of the protein, as evidenced by circular dichroism (CD). The match between the biomolecule size and stereochemistry with the nanoparticle surface cavities characteristics reflects on the nanoparticle surface area that is accessible for each biomolecule to interact and stabilize any non-rigid nanoparticles. On the other hand, in contact with variety of biomolecules such as those present in blood plasma (55%), MSNs are colloidally stabilized regardless of the topography and surface charge, although the identity of the protein corona responsible for this stabilization is influenced by the surface topography and surface charge. Therefore, the biofluid in which nanoparticles are introduced plays an important role on their physicochemical behavior synergistically with their inherent characteristics (e.g., surface topography).