Highly sensitive electrochemical detection of cholesterol based on Au-Pt NPs/PAMAM-ZIF-67 nanomaterials.

A cholesterol biosensor was constructed by bimetallic (Au and Pt) and poly(amidoamine)-zeolite imidazole framework (PAMAM-ZIF-67). First, PAMAM-ZIF-67 nanomaterial was immobilized onto the electrode, and then Au and Pt were modified on the electrode by the electro-deposition method. Subsequently, cholesterol oxidase (ChOx) and cholesterol esterase (ChEt) were fixed on the electrode. The stepwise modification procedures were recorded by impedance spectroscopy and voltammetry. The current response presented a linear relation to the logarithm of cholesterol content when content ranged between 0.00015 and 10.24 mM, and the minimum detection concentration reached 3 nM. The electrode was also used for the cholesterol assay in serum, which hinted at its potentially valuable in clinical diagnostics. An electrochemical biosensor based on gold nanoparticles, platinum nanoparticles, and polyamide-zeolitic imidazolate frameworks was developed for detection of cholesterol. First, polyamide-zeolitic imidazolate frameworks nanomaterial was fixed onto the electrode modified of mercaptopropionic acid by Au-S bond. Then, gold nanoparticles and platinum nanoparticles were electrodeposited on the above electrode. Subsequently, cholesterol oxidase and cholesterol esterase were co-immobilized on the surface of the modified electrode to fabricate the cholesterol biosensor. The biosensor has also been used for the measurement of cholesterol in human serum, which implied potential applications in biotechnology and clinical diagnostics.

Dual Responsive Magnetic Drug Delivery Nanomicelles with Tumor Targeting for Enhanced Cancer Chemo/Magnetothermal Synergistic Therapy.

Introduction: Stimulus-responsive nanocarrier systems are promising in cancer treatment. They improve drug stability and facilitate controlled drug release. However, single-responsive nanocarriers still face insufficient tumor targeting and low efficacy. Methods: In this study, we synthesized folate-modified DSPE-PEOz nanomicelles with PEG chains and loaded them with magnetic iron particles and doxorubicin (DOX). Folic acid (FA) was employed as a ligand to target cancer cells actively. The nanomicelles are biocompatible and acid-sensitive drug carriers. Magnetic field-responsive nanoparticles enable moderately controlled magnetothermal therapy of tumors regardless of tumor location. The pH/magnetic field dual-responsive nanomicelles shed their PEG layer in response to tumor tissue acidity and react to magnetic fields through magnetothermal effects. Results: In vitro and in vivo experiments demonstrated that the nanomicelles could efficiently target cancer cells, release drugs in response to pH changes, and enhance drug uptake through magnetothermal effects. Discussion: The dual-responsive magnetic nanomicelles are expected to enhance the anti-cancer efficacy of chemo/magnetothermal synergistic therapy.

Biosensor based on bimetallic/graphene composite for non-enzymatic detection of hydrogen peroxide in living tumor cells.

A highly sensitive electrochemical biosensor was manufactured with triple synergistic catalysis to detect hydrogen peroxide (H2 O2 ). In this study, a highly sensitive biosensor based on Prussian blue-chitosan/graphene-hemin nanomaterial/platinum and palladium nanoparticles (PB-CS/HGNs/Pt&Pd biosensor) was fabricated for the detection of H2 O2 . The materials described above were modified on the electrode surface and applied to catalyze the breakdown of hydrogen peroxide. The current response of the biosensor presented a linear relationship with H2 O2 concentration from 6 × 10-2 to 20 µM (R2 = 0.9766) and with the logarithm of H2 O2 concentration from 20 to 9×103  µM (R2 = 0.9782), the low detection limit of 25 nM was obtained at the signal/noise (S/N) ratio of 3. Besides, the biosensor showed an outstanding anti-interference ability and acceptable reproducibility. PB-CS/HGNs/Pt&Pd electrodes are effective in measuring H2 O2 from living tumor cells, which implies that the biosensor has the potential to assess reactive oxygen species in various living tumor cells.

Graphene quantum dots mediated magnetic chitosan drug delivery nanosystems for targeting synergistic photothermal-chemotherapy of hepatocellular carcinoma.

Conventional clinical monotherapies for advanced hepatocellular carcinoma (HCC) have numerous limitations. Integrated oncology approaches can improve cancer treatment efficacy, and photothermal-chemotherapy drug delivery nanosystems (DDS) based on nanotechnology and biotechnology have piqued the interest of researchers. This study developed an aptamer-modified graphene quantum dots (GQDs)/magnetic chitosan DDS for photothermal-chemotherapy of HCC. The HCC aptamer and the EPR effect of nanoparticles, in particular, enable active and passive targeting of DDS to HCC. GQDs functioned as photosensitizers, effectively moderating photothermal therapy and inhibiting drug release during blood circulation. Magnetic chitosan demonstrated excellent drug encapsulation, acid sensitivity, and tumor imaging capabilities. Proper assembly of the units mentioned above enables precise combined therapy of HCC. This study indicates that DDS can significantly inhibit tumor growth while also extending the survival duration of tumor-bearing mice. The DDS (DOX-Fe3O4@CGA) shows strong synergistic tumor treatment potential, allowing for the exploration and development of novel HCC therapies.

A novel absorption spectrometric method, based on graphene nanomaterials, for detection of hepatocellular carcinoma-specific T lymphocyte cells.

INTRODUCTION: Detection of antigen-specific cytotoxic T lymphocytes (CTLs) is the foundation for understanding hepatocellular carcinoma immune pathology and hepatocellular carcinoma immunotherapy. However, the classical method for labeling CTLs, major histocompatibility complex (MHC)-peptide tetramer, has drawbacks and needs further improvement. MATERIALS AND METHODS: Here, as a new detection probe, a graphene-based MHC-peptide multimer was developed for sensitively and selectively identifying hepatocellular carcinoma-specific T-cells. To assess its detection efficiency, reduced graphene oxide (RGO) was functionalized with hemin and streptavidin to prepare a functionalized HRGO-streptavidin complex. Biotinylated MHC-peptide monomer was subsequently constructed onto HRGO to generate a detection probe for CTL labeling. The number of T-cells was detected through the reaction between HRGO and tetramethylbenzidine. RESULTS: Using HRGO/MHC-peptide multimers, the number of T-cells was efficiently detected in both the induction system in vitro and in peripheral blood of patients. CONCLUSION: HRGO/MHC-peptide multimers methodology has application prospects in the detection of antigen peptide-specific T cells.