Strategies Employed to Design Biocompatible Metal Nanoparticles for Medical Science and Biotechnology Applications.

The applicability of nanomaterials has evolved in biomedical domains thanks to advances in biocompatibility strategies and the mitigation of cytotoxic effects, allowing diagnostics, imaging, and therapeutic approaches. The application of nanoparticles (NP), particularly metal nanoparticles (mNPs), such as gold (Au) and silver (Ag), includes inherent challenges related to the material characteristics, surface modification, and bioconjugation techniques. By tailoring the surface properties through appropriate coating with biocompatible molecules or functionalization with active biomolecules, researchers can reach a harmonious interaction with biological systems or samples (mostly fluids or tissues). Thus, this review highlights the mechanisms associated with the obtention of biocompatible mNP and presents a comprehensive overview of methods that facilitate safe and efficient production. Therefore, we consider this review to be a valuable resource for all researchers navigating this dynamic field.

Electrochemical immunosensors using electrodeposited gold nanostructures for detecting the S proteins from SARS-CoV and SARS-CoV-2.

This paper reports the development of a low-cost (< US$ 0.03 per device) immunosensor based on gold-modified screen-printed carbon electrodes (SPCEs). As a proof of concept, the immunosensor was tested for a fast and sensitive determination of S proteins from both SARS-CoV and SARS-CoV-2, by a single disposable device. Gold nanoparticles were electrochemically deposited via direct reduction of gold ions on the electrode using amperometry. Capture antibodies from spike (S) protein were covalently immobilized on carboxylic groups of self-assembled monolayers (SAM) of mercaptoacetic acid (MAA) attached to the gold nanoparticles. Label-free detection of S proteins from both SARS-CoV and SARS-CoV-2 was performed with electrochemical impedance spectroscopy (EIS). The immunosensor fabricated with 9 s gold deposition had a high performance in terms of selectivity, sensitivity, and low limit of detection (LOD) (3.16 pmol L-1), thus permitting the direct determination of the target proteins in spiked saliva samples. The complete analysis can be carried out within 35 min using a simple one-step assay protocol with small sample volumes (10 µL). With such features, the immunoplatform presented here can be deployed for mass testing in point-of-care settings.

In vitro and in vivo antileishmania activity of sesquiterpene lactone-rich dichloromethane fraction obtained from Tanacetum parthenium (L.) Schultz-Bip.

The discovery of new treatments for neglected diseases, including leishmaniasis, is a substantial challenge for scientific research. Plant extracts have shown potential in the selective treatment of tropical diseases. The present study evaluated the in vitro and in vivo antileishmania effects of a sesquiterpene lactone-rich dichloromethane fraction (DF) obtained from the aerial parts of Tanacetum parthenium (L.) Schultz-Bip. In vitro studies of the DF indicated an IC50 of 2.40±0.76 µg mL(-1) against the promastigote form and 1.76±0.25 µg mL(-1) against the axenic amastigote form of Leishmania amazonensis. In vivo intramuscular treatment with DF decreased the growth and size of footpad lesions in mice. The DF also significantly decreased the parasite population compared with animals that were treated with the reference drug. Plasma malondialdehyde levels were increased slightly by the DF, attributable to its parthenolide-rich composition that causes cellular apoptosis, compared with the control group, demonstrating treatment efficacy without toxicity or genotoxicity. Because the isolation and purification of plant compounds are costly and time-consuming and generate low yields, extract fractions, such as the DF studied herein, represent a promising alternative for the treatment of leishmaniasis.