Due to the rapid development and superb performance of electronic skin, we propose a highly sensitive and stretchable temperature and strain sensor. Silver nanoparticles coated carbon nanowires (Ag@CNT) nanomaterials with different Ag concentrations were synthesized. After the morphology and components of the nanomaterials were demonstrated, the sensors composed of Polydimethylsiloxane (PDMS) and CNTs or Ag@CNTs were prepared via a simple template method. Then, the electronic properties and piezoresistive effects of the sensors were tested. Characterization results present excellent performance of the sensors for the highest gauge factor (GF) of the linear region between 0–17.3% of the sensor with Ag@CNTs1 was 137.6, the sensor with Ag@CNTs2 under the strain in the range of 0–54.8% exhibiting a perfect linearity and the GF of the sensor with Ag@CNTs2 was 14.9.
Herein, a pH and redox dual-responsive drug delivery system (CDs–Pt(IV)–PEG) was developed based on fluorescence carbon dots (CDs). In this system, cisplatin(IV) prodrug (Pt(IV)) was selected as a model drug to reduce toxic side effects. The aldehyde-functionalized monomethoxy polyethylene glycol (mPEG-CHO) was conjugated to CDs–Pt(IV) to form pH sensitive benzoic imine bond. Owing to the slightly acidic tumor extracellular microenvironment (pH 6.8), the benzoic imine bond was then hydrolyzed, leading to charge reversal and decrease in the hydration radius of the drug-carrying, which facilitated in vivo circulation and tumor targeting. Notably, the cytotoxicity of the drug delivery system on cancer cells was comparable to that of cisplatin, while the side effects on normal cells were significantly reduced. In addition, the system realized recognition of cancer cells by the high-contrast fluorescent imaging. In conclusion, the CDs–Pt(IV)–PEG system provided a promising potential for effective delivery of anticancer drugs and cancer cells screening.
This paper presents an original design for a volume refractive index (RI) sensor for cell concentration detection based on the unique resonant optical tunneling effect (ROTE). In this design, the solution sample is introduced into the ROTE resonant cavity, whose reflection spectrum presents a large shift of its resonant dip in response to the tiny change of the solution RI. Performance calibration using the polystyrene particle solution indicates that the sensitivity is 19,000 nm/RIU and the total Q factor is 620. Experiments with hepatoma cells have obtained sensitivity values as high as 2.53 nm/(amol/ml) and a detection limit of 1.2 × 10 5 cells/ml. Compared with previously reported optical cell sensors, this original work implements the ROTE mechanism for the first time and presents superior device performance. Thus, the proposed design has a high potential for use in biomedical applications, such as drug discovery, cell research, and medical diagnoses.
Noble metal nanomaterials are particularly suitable as photothermal transduction agents (PTAs) with high photothermal conversion efficiency (PCE) due to local surface plasmon resonance (LSPR). Studies on different gold–platinum (Au–Pt) bimetal nanoparticles exhibiting the LSPR effect have provided a new idea for the synthesis of excellent PTAs. But there is no simple and scalable method for the controllable synthesis of Au–Pt nanoparticles with adjustable LSPR wavelength range. In this work, the effects of Ag+ and K2PtCl4 on the deposition of Pt on the surface of gold nanorods (AuNRs) were investigated. A fast, precise, and controlled synthesis of dumbbell-like Pt-coated AuNRs (Au@Pt NRs) under mild conditions is proposed. The synthesized Au@Pt NRs have a longitudinal LSPR wavelength of 812 nm, which is very close to a common laser wavelength of 808 nm. The Au@Pt NRs exhibit excellent photothermal properties when irradiated with a laser. The temperature increased by more than 36 °C after irradiation for 10 min, with a PCE of about 78.77%, which is much higher than that of AuNRs (57.33%). In addition, even after four on/off cycles, the Au@Pt NRs are able to maintain the photothermal properties and retain their optical properties, indicating that they have excellent photothermal stability and reusability.