The detection of glucose plays an important role in the diagnosis, treatment and control of human diseases. The enzyme-based electrochemical sensors for glucose detection have the advantages of high sensitivity, good selectivity and mild conditions. However, the enzyme activity is easily interfered by external conditions, which limits the application of enzyme-based sensors. By contrary, enzyme-free sensors can overcome these shortcomings and achieve continuous glucose monitoring. Recently, various materials have been developed and applied for electrochemical detection of glucose. This review summarized the recent progress and application prospects of enzyme-based and enzyme-free electrochemical glucose sensors.

Interleukins (ILs) are closely related to the occurrence and progress of many diseases including neuropsychiatric syndrome and Crohn's disease. Therefore, it is of great importance to determining ILs for the early diagnosis and treatment of diseases. Electrochemical biosensors are the promising candidates for the sensitive and specific detection of ultra-low level of biomarkers. This review summarized the development of nanomaterials-based electrochemical biosensors for ILs detection. It was highlighted that the utilization of nanomaterials as the electrode materials and the signal reporters or carriers for the construction of electrochemical biosensors.

Neoadjuvant chemotherapy is an alternative treatment modality for tumors. Methotrexate (MTX) has been often used as a neoadjuvant chemotherapy reagent for osteosarcoma surgery. However, the large dosage, high toxicity, strong drug resistance, and poor improvement of bone erosion restricted the utilization of methotrexate. Here, we developed a targeted drug delivery system using nanosized hydroxyapatite particles (nHA) as the cores. MTX was conjugated to polyethylene glycol (PEG) through the pH-sensitive ester linkage and acted as both the folate receptor-targeting ligand and the anti-cancer drug due to the similarity to the structure of folic acid. Meanwhile, nHA could increase the concentration of calcium ions after being uptake by cells, thus inducing mitochondrial apoptosis and improving the efficacy of medical treatment. In vitro drug release studies of MTX-PEG-nHA in phosphate buffered saline at different pH values (5, 6.4 and 7.4) indicated that the system showed a pH-dependent release feature because of the dissolution of ester bonds and nHA under acidic conditions. Furthermore, the treatment on osteosarcoma cells (143B, MG63, and HOS) by using MTX-PEG-nHA was demonstrated to exhibit higher therapeutic efficacy. Therefore, the developed platform possesses the great potential for osteosarcoma therapy.

Kinase can be used in clinical analysis as the biomarker for disease diagnosis. Herein, we proposed a simple and label-free electrochemical method for kinase detection. The method was based on the charge change of peptide substrate immobilized on the gold electrode. The change was measured by electrochemical impedance spectroscopy and the value was proportional to the concentration of kinase. The method shows satisfactory results for the analysis of kinase inhibitors, thus exhibiting great potential for diagnosis of kinase-related diseases and discovery of novel inhibitor drugs.