Biogenic silver nanoparticles are synthesized through silver(I) reduction, which is promoted by biomolecules available in the biological world and mostly obtained from plant extracts, fungal bioproduction, and some bacteria. The exact mechanisms accounting for such oxidoreduction processes are not fully known. However, some studies have already mentioned oxidoreductases, cofactors (nicotinamide adenine dinucelotide hydrogen (NADH), dihydroflavine-adenine dinucleotid (FADH2)), and phenolic compounds, as the main reductive species engaged in the formation of silver(0) and silver nanoparticles (silver NPs) synthesis. Biosynthesis is a one-pot process that leads to stable silver NP colloids that, regarding their size, shape, and uniformity, can be successfully controlled; and show great stability when one takes into account their surface capping by some biomolecules that as well take part in their synthesis. Although great efforts have been made to feature capping biomolecules and their interactions with silver NP surfaces, knowledge of the quantity (exact number per cm2) and type of biomolecules that cap or surround silver NPs remains limited. The literature provides detailed information on protein capping, but it still shows gaps regarding many aspects of fine biophysical protein featuring. The reason why certain proteins prefer to interact with silver NP surface and form chemical bonds, whereas others rather have intermolecular interaction with the first layer of proteins remains unknown. Assessing capping proteins’ involvement in the bioactivity of biogenic silver NPs is another relevant research field. Certain proteins enhance bioactivity of silver NPs and lower toxicity; however, the way antimicrobial processes benefit from protein capping is yet to be discovered. Finally, biogenic silver NPs can be found both in the environment and in water; moreover, their additional activity and behavior must be known or, at least, hypothesized.

Silver nanoparticles (AgNPs) have important antimicrobial activity. These nanoparticles are present in several commercial products, leading to human and environmental exposure. This review presents a critical view of the toxic effects of Ag NPs on in vitro and in vivo biological models. It is noteworthy that the toxicity of AgNPs is dependent on several parameters, such as the preparation mode of the colloidal suspension of the nanoparticles, their state of aggregation, the chemical nature of the nanoparticles, surface size, morphology, dose, cell type, nature of the living organism, among others. In general, low concentrations of AgNPs do not present significant toxicity in in vitro and in vivo assays, however with the increase of the concentration of AgNPs there is a significant increase of nanoparticle toxicity and its accumulation in diverse tissues/organs. It should be emphasized that in living organisms, exposure routes should be taken into account, such as ingestion and inhalation. At high concentrations, inhalation or ingestion of AgNPs can cause adverse effects and even lead to human death. In this context, the importance of further studies of the toxicity of AgNPs in several in vitro and in vivo models is emphasized.

The ecological processes in which metabolites with industrial or medical applications are produced are of great importance. Magnesium plays many important roles in environmental and medical applications. Phosphorus is obtained by mining. It is estimated to have a very limited half-life and expected to be depleted as a resource in 100 years. Its recovery by mining and subsequent marketing as phosphate has important environmental implications. These processes are part of an important recovery technology. Bacteria have contributed to the formation of minerals since the advent of life on Earth. Bacterial and/or fungal biomineralizations play a critical role in biogeochemical cycles. These processes have important technological and environmental applications. In many past publications dealing with bacterial and fungal recovery of phosphates as insoluble products, magnesium played an important role. This is a review of recent progress in the microbial recovery of biogenic magnesium phosphate compounds, their importance, and their roles in treatment of several human diseases.

The primary treatment for high-grade non-muscle invasive bladder cancer (NMIBC) is based on surgery by transurethral resection of bladder tumor (TURBT), followed by intravesical immunotherapy with Bacillus Calmette-Guerin (BCG) to prevent recurrence and to reduce the tumor progression. However, BCG therapy shows several undesirable effects. The current treatment on NMIBC is doxorubicin (DOX), but with high toxicity. Our nanotechnology strategy was done through scaffolds for the NMIBC treatment: graphene oxide (GO) and a nanostructured lipid carrier (NLC). A GO hybrid for administration of DOX and small interfering RNA (siRNA) was developed. This hybrids administered in vivo against NMIBC in rats gave absence of lesions. NLC was prepared by using a mixture of two lipids stabilized by a surfactant and DOX by high homogenization pressure technique. In this case showed a 20% of the animals exhibited benign lesions (papillary hyperplasia), however, in the presence of siRNA reached 40% of rats with benignant lesions. These two scaffolds are potential new drugs for DOX for bladder cancer treatment without any cardiotoxicity problems.

Sentinel node (SN) status is the most important prognostic factor for localized melanoma. Usually, patients with Breslow thickness of less than 1.0 mm are not included in SN protocols. However, the literature presents a rate ranging from 3 to 7% of nodal recurrence in thin melanoma. Ulceration, regression and high mitotic rate have been considered to be indications for an SN biopsy. The metastatic potential of the vertical growth phase is uncertain. To correlate pathological features in thin melanoma with SN metastasis, we reviewed 358 patients submitted to SN biopsy. Seventy-seven patients with lesions of 1 mm or smaller were included in the study group. Histological evaluation of the primary tumor included thickness, Clark level, mitotic rate, ulceration, regression, and growth phase. Lymphoscintigraphy was performed on all patients. Lymphatic mapping and gamma probe detection were both used for SN biopsy. Histological examination of SN consisted of hematoxylin-eosin and immunohistochemical staining. Median follow-up was 37 months. Six patients had micrometastases. Statistical analysis by the Fisher test showed that ulceration (P = 0.019), high mitotic rate (P = 0.008) and vertical growth phase (P = 0.002) were positively correlated with micrometastases. If other studies confirm these results, more melanoma patients must be submitted to SN biopsy.