Simultaneous label-free live imaging of cell nucleus and luminescent nanodiamonds

Tracking intracellular nuclear targeted-chemotherapy of chidamide-loaded Prussian blue nanocarriers by SERS mapping

The novel histone deacetylase drug chidamide (CHI) has been proven to regulate gene expression associated with oncogenesis via epigenetic mechanisms. However, huge side effects such as non-targeting, poor intracellular accumulation and low nuclear entry efficiency severely restrict its therapeutic efficacy. Dual-targeted nanodrug delivery systems have been proposed as the solution. Herein, we developed a CHI-loaded drug delivery nanosystem based on Prussian blue (PB) nanocarrier, which combines surface-enhanced Raman scattering (SERS) tracking function with cancer cell/nuclear-targeted chemotherapy capability. With the property of background-free SERS mapping, PB nanocarriers can serve as tracking agents to localize intracellular CHI. The incorporation of targeted molecules specifically enhances the cancer cell/nuclear internalization and chemotherapeutic effects of CHI-loaded PB nanocarriers. In vitro cytotoxicity assay clearly shows that the constructed CHI-loaded PB nanocarriers have significant inhibitory on Jurkat cell proliferation. Furthermore, SERS spectral analysis of Jurkat cells incubated with the CHI-loaded PB nanocarriers reveals obvious features of cellular apoptosis: DNA skeleton fragmentation, chromatin depolymerization, histone acetylation, and nucleosome conformation change. Importantly, this CHI-loaded PB nanocarrier will provide a new insight for lymphoblastic leukemia targeted chemotherapy.

Biomedical applications of nanodiamonds: From drug-delivery to diagnostics

Advances in nanotechnology have great potential to address many unmet clinical and biomedical needs. Nanodiamonds, as a class of carbon nanoparticles with unique properties, may be useful towards a versatile range of biomedical applications from drug delivery to diagnostics. This review describes how these properties of nanodiamonds facilitate their application in different fields of biomedicine, including delivery of chemotherapy drugs, peptides, proteins, nucleic acids and biosensors. Additionally, clinical potential of nanodiamonds, with studies in both preclinical and clinical stages, is also reviewed here, highlighting the translational potential of nanodiamonds in biomedical research.

Recent Development of Fluorescent Nanodiamonds for Optical Biosensing and Disease Diagnosis

The ability to precisely monitor the intracellular temperature directly contributes to the essential understanding of biological metabolism, intracellular signaling, thermogenesis, and respiration. The intracellular heat generation and its measurement can also assist in the prediction of the pathogenesis of chronic diseases. However, intracellular thermometry without altering the biochemical reactions and cellular membrane damage is challenging, requiring appropriately biocompatible, nontoxic, and efficient biosensors. Bright, photostable, and functionalized fluorescent nanodiamonds (FNDs) have emerged as excellent probes for intracellular thermometry and magnetometry with the spatial resolution on a nanometer scale. The temperature and magnetic field-dependent luminescence of naturally occurring defects in diamonds are key to high-sensitivity biosensing applications. Alterations in the surface chemistry of FNDs and conjugation with polymer, metallic, and magnetic nanoparticles have opened vast possibilities for drug delivery, diagnosis, nanomedicine, and magnetic hyperthermia. This study covers some recently reported research focusing on intracellular thermometry, magnetic sensing, and emerging applications of artificial intelligence (AI) in biomedical imaging. We extend the application of FNDs as biosensors toward disease diagnosis by using intracellular, stationary, and time-dependent information. Furthermore, the potential of machine learning (ML) and AI algorithms for developing biosensors can revolutionize any future outbreak.

Specific intracellular signature of SARS-CoV-2 infection using confocal Raman microscopy

SARS-CoV-2 infection remains spread worldwide and requires a better understanding of virus-host interactions. Here, we analyzed biochemical modifications due to SARS-CoV-2 infection in cells by confocal Raman microscopy. Obtained results were compared with the infection with another RNA virus, the measles virus. Our results have demonstrated a virus-specific Raman molecular signature, reflecting intracellular modification during each infection. Advanced data analysis has been used to distinguish non-infected versus infected cells for two RNA viruses. Further, classification between non-infected and SARS-CoV-2 and measles virus-infected cells yielded an accuracy of 98.9 and 97.2 respectively, with a significant increase of the essential amino-acid tryptophan in SARS-CoV-2-infected cells. These results present proof of concept for the application of Raman spectroscopy to study virus-host interaction and to identify factors that contribute to the efficient SARS-CoV-2 infection and may thus provide novel insights on viral pathogenesis, targets of therapeutic intervention and development of new COVID-19 biomarkers.

Toward Quantitative Bio-sensing with Nitrogen-Vacancy Center in Diamond

The long-dreamed-of capability of monitoring the molecular machinery in living systems has not been realized yet, mainly due to the technical limitations of current sensing technologies. However, recently emerging quantum sensors are showing great promise for molecular detection and imaging. One of such sensing qubits is the nitrogen-vacancy (NV) center, a photoluminescent impurity in a diamond lattice with unique room-temperature optical and spin properties. This atomic-sized quantum emitter has the ability to quantitatively measure nanoscale electromagnetic fields via optical means at ambient conditions. Moreover, the unlimited photostability of NV centers, combined with the excellent diamond biocompatibility and the possibility of diamond nanoparticles internalization into the living cells, makes NV-based sensors one of the most promising and versatile platforms for various life-science applications. In this review, we will summarize the latest developments of NV-based quantum sensing with a focus on biomedical applications, including measurements of magnetic biomaterials, intracellular temperature, localized physiological species, action potentials, and electronic and nuclear spins. We will also outline the main unresolved challenges and provide future perspectives of many promising aspects of NV-based bio-sensing.

Adsorption of proteins on TiO2 particles influences their aggregation and cell penetration

TiO₂ nanoparticles known as E171 are one controversial food additive due to its potential toxicity. In this work, the main hypothesis is that the proteins adsorbed on the TiO₂ nanoparticles prevent their aggregation and favor the cell penetration. To do so, the TiO₂ nanoparticles were coated with gelatin and β-lactoglobulin to reach interfacial concentrations about 0.25 mg/mg and 0.32 mg/mg, respectively. The measurement of NP size showed that the protein coating improve the colloidal stability of TiO₂ nanoparticles. The FTIR analysis suggests that the β-lactoglobulin structure is modified after adsorption. The penetration of TiO₂ penetration inside human intestinal epithelial cells was shown and quantify by using confocal Raman microscopy. The promoting role of the protein coating on the cell penetration was demonstrated for both the gelatin and β-lactoglobulin. Finally, the results allow establishing a correlation between the ability of proteins to prevent NP aggregation and the cell penetration.